Biofortified indica rice attains iron and zinc nutrition dietary targets in the field

USDA-ARS?s Scientific Manuscript database

Iron (Fe) and zinc (Zn) deficiencies are the most prevalent micronutrient malnutrition globally1. Fe in rice has proven efficacious in improving serum ferritin concentration and body Fe levels2. Rapid progress in biofortification demonstrates the feasibility to enhance Fe in polished rice by expre...

Iron and zinc isotope fractionation during uptake and translocation in rice (Oryza sativa) grown in oxic and anoxic soils

NASA Astrophysics Data System (ADS)

Arnold, Tim; Markovic, Tamara; Kirk, Guy J. D.; Schönbächler, Maria; Rehkämper, Mark; Zhao, Fangjie J.; Weiss, Dominik J.

2015-11-01

Stable isotope fractionation is emerging quickly as a powerful novel technique to study metal uptake and translocation in plants. Fundamental to this development is a thorough understanding of the processes that lead to isotope fractionation under differing environmental conditions. In this study, we investigated Zn and Fe isotope fractionation in rice grown to maturity in anaerobic and aerobic soils under greenhouse conditions. The overall Zn isotope fractionation between the soil and above ground plant material was negligible in aerobic soil but significant in anaerobic soil with isotopically lighter Zn in the rice plant. The observed range of fractionation is in line with previously determined fractionations of Zn in rice grown in hydroponic solutions and submerged soils and emphasizes the effect of taking up different chemical forms of Zn, most likely free and organically complexed Zn. The Zn in the grain was isotopically lighter than in the rest of the above ground plant in rice grown in aerobic and anaerobic soils alike. This suggests that in the course of the grain loading and during the translocation within the plant important biochemical and/or biophysical processes occur. The isotope fractionation observed in the grains would be consistent with an unidirectional controlled transport from shoot to grain with a fractionation factor of α ≈ 0.9994. Iron isotopes showed an isotopic lighter signature in shoot and grain compared to the bulk soil or the leachate in aerobic and anaerobic soils alike. The negative direction of isotopic fractionation is consistent with possible changes in the redox state of Fe occurring during the uptake and translocation processes. The isotope fractionation pattern between shoots and grain material are different for Zn and Fe which finally suggests that different mechanisms operate during translocation and grain-loading in rice for these two key micronutrients.

Gibberellins regulate iron deficiency-response by influencing iron transport and translocation in rice seedlings (Oryza sativa).

PubMed

Wang, Baolan; Wei, Haifang; Xue, Zhen; Zhang, Wen-Hao

2017-04-01

Gibberellins (GAs) are a class of plant hormones with diverse functions. However, there has been little information on the role of GAs in response to plant nutrient deficiency. To evaluate the roles of GAs in regulation of Fe homeostasis, the effects of GA on Fe accumulation and Fe translocation in rice seedlings were investigated using wild-type, a rice mutant ( eui1 ) displaying enhnaced endogenous GA concentrations due to a defect in GA deactivation, and transgenic rice plants overexpressing OsEUI . Exposure to Fe-deficient medium significantly reduced biomass of rice plants. Both exogenous application of GA and an endogenous increase of bioactive GA enhanced Fe-deficiency response by exaggerating foliar chlorosis and reducing growth. Iron deficiency significantly suppressed production of GA 1 and GA 4 , the biologically active GAs in rice. Exogenous application of GA significantly decreased leaf Fe concentration regardless of Fe supply. Iron concentration in shoot of eui1 mutants was lower than that of WT plants under both Fe-sufficient and Fe-deficient conditions. Paclobutrazol, an inhibitor of GA biosynthesis, alleviated Fe-deficiency responses, and overexpression of EUI significantly increased Fe concentration in shoots and roots. Furthermore, both exogenous application of GA and endogenous increase in GA resulting from EUI mutation inhibited Fe translocation within shoots by suppressing OsYSL2 expression, which is involved in Fe transport and translocation. The novel findings provide compelling evidence to support the involvement of GA in mediation of Fe homeostasis in strategy II rice plants by negatively regulating Fe transport and translocation. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Zinc allocation and re-allocation in rice.

PubMed

Stomph, Tjeerd Jan; Jiang, Wen; Van Der Putten, Peter E L; Struik, Paul C

2014-01-01

Agronomy and breeding actively search for options to enhance cereal grain Zn density. Quantifying internal (re-)allocation of Zn as affected by soil and crop management or genotype is crucial. We present experiments supporting the development of a conceptual model of whole plant Zn allocation and re-allocation in rice. Two solution culture experiments using (70)Zn applications at different times during crop development and an experiment on within-grain distribution of Zn are reported. In addition, results from two earlier published experiments are re-analyzed and re-interpreted. A budget analysis showed that plant zinc accumulation during grain filling was larger than zinc allocation to the grains. Isotope data showed that zinc taken up during grain filling was only partly transported directly to the grains and partly allocated to the leaves. Zinc taken up during grain filling and allocated to the leaves replaced zinc re-allocated from leaves to grains. Within the grains, no major transport barrier was observed between vascular tissue and endosperm. At low tissue Zn concentrations, rice plants maintained concentrations of about 20 mg Zn kg(-1) dry matter in leaf blades and reproductive tissues, but let Zn concentrations in stems, sheath, and roots drop below this level. When plant zinc concentrations increased, Zn levels in leaf blades and reproductive tissues only showed a moderate increase while Zn levels in stems, roots, and sheaths increased much more and in that order. In rice, the major barrier to enhanced zinc allocation towards grains is between stem and reproductive tissues. Enhancing root to shoot transfer will not contribute proportionally to grain zinc enhancement.

Zinc allocation and re-allocation in rice

PubMed Central

Stomph, Tjeerd Jan; Jiang, Wen; Van Der Putten, Peter E. L.; Struik, Paul C.

2014-01-01

Aims: Agronomy and breeding actively search for options to enhance cereal grain Zn density. Quantifying internal (re-)allocation of Zn as affected by soil and crop management or genotype is crucial. We present experiments supporting the development of a conceptual model of whole plant Zn allocation and re-allocation in rice. Methods: Two solution culture experiments using 70Zn applications at different times during crop development and an experiment on within-grain distribution of Zn are reported. In addition, results from two earlier published experiments are re-analyzed and re-interpreted. Results: A budget analysis showed that plant zinc accumulation during grain filling was larger than zinc allocation to the grains. Isotope data showed that zinc taken up during grain filling was only partly transported directly to the grains and partly allocated to the leaves. Zinc taken up during grain filling and allocated to the leaves replaced zinc re-allocated from leaves to grains. Within the grains, no major transport barrier was observed between vascular tissue and endosperm. At low tissue Zn concentrations, rice plants maintained concentrations of about 20 mg Zn kg−1 dry matter in leaf blades and reproductive tissues, but let Zn concentrations in stems, sheath, and roots drop below this level. When plant zinc concentrations increased, Zn levels in leaf blades and reproductive tissues only showed a moderate increase while Zn levels in stems, roots, and sheaths increased much more and in that order. Conclusions: In rice, the major barrier to enhanced zinc allocation towards grains is between stem and reproductive tissues. Enhancing root to shoot transfer will not contribute proportionally to grain zinc enhancement. PMID:24478788

Assessment of total soil and plant trace elements in rice-based production systems in NE Italy

NASA Astrophysics Data System (ADS)

Bini, Claudio; Nadimi-Goki, Mandana; Kato, Yoichi; Vianello, Gilmo; Vittori, Livia; Wahsha, Mohammad; Spiandorello, Massimo

2014-05-01

Macro- and micronutrients concentrations, and PTEs contents in soils and plants (rice) from the rice district in the Venetian territory (NE Italy) have been determined by ICP-MS spectrometry, with the following aims: - to determine the background levels of macro- and microelements in the study area; - to assess possible contamination of soils and plants; - to calculate the Translocation Factor (TF) of metals from soil to plant, and the possible hazard for human health. Four rice plots with different rotation systems were investigated from seedling time to harvesting; sampling of soils (0-30cm) and plants was carried out 4 times during growing season (three replicates). Rice plants were separated into roots, stems, leaves and grains, and then oven-dried. Chemical and physical analyses were carried out at the Soil Science Lab of the University of Bologna and Venice, respectively. The results obtained point to a land with moderate soil contamination by trace elements (namely Li, Sn, Tl, Sr, Ti, Fe). Heavy metal (Sb, As, Be, Cd, Co, Cr, Ni, Pb, Cu, V, Zn ) concentrations in soils are below the threshold indicated by the Italian legislation (DM 152/2006). Cd, Sn, and Ti contents in soils are positively correlated with soil pH, while As, Fe, Li, Ti, Tl and Zn are negatively correlated with organic matter content. With the exception of Strontium, soil metal contents are always correlated between variable couples. HMs in plants vary according to the sampling season, texture and moisture, and soil pH. Most non-essential trace elements are accumulated in rice roots and, only in cases of essential micronutrients, in leaves. Therefore, rice can be assumed as an accumulator plant of As, Pb, Cr, Ba, and Ti, whereas it is as an indicator plant for Cu, Fe, Ni, Mn and Zn. The results of multiple linear regression analysis showed that soil pH has a larger effect on Ba, Cr, Cu, Fe, Mn, Ni, Ti and Zn concentrations in grain than other soil parameters. The average translocation of metals from soil to root was found to be >1, irrespective of the essential/not essential function; conversely, only essential elements ((Cu, Fe, Mn, Zn) are translocated rather easily from roots to leaves (TF ≤1) via phloem (TF< <1), and very little translocated to grains (TF< <1). Therefore, it is suggested that rice could be useful in contaminated-sites restoration projects by the phytostabilization technique. Moreover, there is very limited hazard for human population consuming rice crops. Key Words: Macro- and micronutrients concentrations, heavy metals, trace elements, rice plant, Italy, accumulator plant, indicator plant * Corresponding author. Tel.: +39 3891356251 E-mail address: mandy.nadimi@gmail.com

Comparative study of Zn deficiency in L. sativa and B. oleracea plants: NH4(+) assimilation and nitrogen derived protective compounds.

PubMed

Navarro-León, Eloy; Barrameda-Medina, Yurena; Lentini, Marco; Esposito, Sergio; Ruiz, Juan M; Blasco, Begoña

2016-07-01

Zinc (Zn) deficiency is a major problem in agricultural crops of many world regions. N metabolism plays an essential role in plants and changes in their availability and their metabolism could seriously affect crop productivity. The main objective of the present work was to perform a comparative analysis of different strategies against Zn deficiency between two plant species of great agronomic interest such as Lactuca sativa cv. Phillipus and Brassica oleracea cv. Bronco. For this, both species were grown in hydroponic culture with different Zn doses: 10μM Zn as control and 0.01μM Zn as deficiency treatment. Zn deficiency treatment decreased foliar Zn concentration, although in greater extent in B. oleracea plants, and caused similar biomass reduction in both species. Zn deficiency negatively affected NO3(-) reduction and NH4(+) assimilation and enhanced photorespiration in both species. Pro and GB concentrations were reduced in L. sativa but they were increased in B. oleracea. Finally, the AAs profile changed in both species, highlighting a great increase in glycine (Gly) concentration in L. sativa plants. We conclude that L. sativa would be more suitable than B. oleracea for growing in soils with low availability of Zn since it is able to accumulate a higher Zn concentration in leaves with similar biomass reduction. However, B. oleracea is able to accumulate N derived protective compounds to cope with Zn deficiency stress. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Effect of different amendments on rice (Oryza sativa L.) growth, yield, nutrient uptake and grain quality in Ni-contaminated soil.

PubMed

Ramzani, Pia Muhammad Adnan; Khan, Waqas-Ud-Din; Iqbal, Muhammad; Kausar, Salma; Ali, Shafaqat; Rizwan, Muhammad; Virk, Zaheer Abbas

2016-09-01

Rice ( Oryza sativa L.) is one of the main staple food crops which is inherently low in micronutrients, especially iron (Fe), and can lead to severe Fe deficiency in populations having higher consumption of rice. Soils polluted with nickel (Ni) can cause toxicity to rice and decreased Fe uptake by rice plants. We investigated the potential role of biochar (BC) and gravel sludge (GS), alone and in combination, for in situ immobilization of Ni in an industrially Ni-contaminated soil at original and sulfur-amended altered soil pH. Our further aim was to increase Fe bioavailability to rice plants by the exogenous application of ferrous sulfate to the Ni-immobilized soil. Application of the mixture of both amendments reduced grain Ni concentration, phytate, Phytate/Fe, Phyt/Zn molar ratios, and soil DTPA-extractable Ni. In addition, the amendment mixture increased 70 % Fe and 229 % ferritin concentrations in rice grains grown in the soil at original pH. The Fe and ferritin concentrations in S-treated soil was increased up to 113 and 383 % relative to control respectively. This enhanced Fe concentration and corresponding ferritin in rice grains can be attributed to Ni/Fe antagonism where Ni has been immobilized by GS and BC mixture. This proposed technique can be used to enhance growth, yield, and Fe biofortification in rice by reducing soil pH while in parallel in situ immobilizing Ni in polluted soil.

Rice OsMYB5P improves plant phosphate acquisition by regulation of phosphate transporter

PubMed Central

Yun, Dae-Jin; Lee, Kwang Sik; Hong, So Yeon; Bae, Ki Deuk; Chung, Young Soo; Kwon, Yong Sham; Kim, Du Hyun; Jung, Ki Hong

2018-01-01

Myeloblastosis (MYB) transcription factors play central roles in plant developmental processes and in responses to nutrient deficiency. In this study, OsMYB5P, an R2R3-MYB transcription factor, was isolated and identified from rice (Oryza sativa L. ‘Dongjin’) under inorganic phosphate (Pi)-deficient conditions. OsMYB5P protein is localized to the nucleus and functions as a transcription activator in plant development. Overexpression of OsMYB5P in rice and Arabidopsis (Arabidopsis thaliana Col-0) increases tolerance to phosphate starvation, whereas OsMYB5P knock-out through RNA interference increases sensitivity to Pi depletion in rice. Furthermore, shoots and roots of transgenic rice plants overexpressing OsMYB5P were longer than those of wild plants under both normal and Pi-deficient conditions. These results indicate that OsMYB5P is associated with the regulation of shoot development and root- system architecture. Overexpression of OsMYB5P led to increased Pi accumulation in shoots and roots. Interestingly, OsMYB5P directly bound to MBS (MYB binding site) motifs on the OsPT5 promoter and induced transcription of OsPT5 in rice. In addition, overexpression of OsMYB5P in Arabidopsis triggered increased expression of AtPht1;3, an Arabidopsis Pi transporter, in shoots and roots under normal and Pi-deficient conditions. Together, these results demonstrate that overexpression of OsMYB5P increases tolerance to Pi deficiency in plants by modulating Pi transporters at the transcriptional level in monocots and dicots. PMID:29566032

Silicon addition to soybean (Glycine max L.) plants alleviate zinc deficiency.

PubMed

Pascual, Ma Blanca; Echevarria, Virginia; Gonzalo, Ma José; Hernández-Apaolaza, Lourdes

2016-11-01

It is well established the beneficial role of silicon (Si) in alleviating abiotic stress. However, it remains poorly understood the mechanisms of the Si-mediated protection against metal deficiency, especially the zinc (Zn) one. Recently, it has been proposed that Si may act by an interaction with this biometal in the root apoplast contributing to its movement through the plant, as in the case of Fe deficiency. In the present work, the effect of initial or continuous Si doses in soybean Zn deficient plants has been studied. For that purpose, plants grown in hydroponic culture were treated with different Si doses (0.0, 0.5 and 1.0 mM) under Zn limiting conditions. SPAD index in leaves, several growth parameters, mineral content in the whole plant and the formation of Zn pools in roots were determined. An initial addition of 0.5 mM of Si to the nutrient solution led to an enhancement of plants growth, Zn and Si content in leaves, and a higher storage of Zn in the root apoplast. The results suggest that this treatment enhanced Zn accumulation on roots and its movement to shoots when needed, mitigating Zn deficiency symptoms. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Heavy metal contaminations in soil-rice system: source identification in relation to a sulfur-rich coal burning power plant in Northern Guangdong Province, China.

PubMed

Wang, Xiangqin; Zeng, Xiaoduo; Chuanping, Liu; Li, Fangbai; Xu, Xianghua; Lv, Yahui

2016-08-01

Heavy metal contents (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in 99 pairs of soil-rice plant samples were evaluated from the downwind directions of a large thermal power plant in Shaoguan City, Guangdong Province, China. Results indicate that there is a substantial buildup of As, Cd, Cu, Pb, and Zn in the predominant wind direction of the power plant. The significant correlations between S and heavy metals in paddy soil suggest that the power plant represents a source of topsoil heavy metals in Shaoguan City due to sulfur-rich coal burning emissions. Elevated Cd concentrations were also found in rice plant tissues. Average Cd (0.69 mg kg(-1)) and Pb (0.39 mg kg(-1)) contents in rice grain had exceeded their maximum permissible limits (both were 0.2 mg kg(-1)) in foods of China (GB2762-2005). The enrichment of Cd and Pb in rice grain might pose a potential health risk to the local residents.

Bioavailability of Zinc in Wistar Rats Fed with Rice Fortified with Zinc Oxide

PubMed Central

Della Lucia, Ceres Mattos; Santos, Laura Luiza Menezes; Rodrigues, Kellen Cristina da Cruz; Rodrigues, Vivian Cristina da Cruz; Martino, Hércia Stampini Duarte; Pinheiro Sant’Ana, Helena Maria

2014-01-01

The study of zinc bioavailability in foods is important because this mineral intake does not meet the recommended doses for some population groups. Also, the presence of dietary factors that reduce zinc absorption contributes to its deficiency. Rice fortified with micronutrients (Ultra Rice®) is a viable alternative for fortification since this cereal is already inserted into the population habit. The aim of this study was to evaluate the bioavailability of zinc (Zn) in rice fortified with zinc oxide. During 42 days, rats were divided into four groups and fed with diets containing two different sources of Zn (test diet: UR® fortified with zinc oxide, or control diet: zinc carbonate (ZnCO3)), supplying 50% or 100%, respectively, of the recommendations of this mineral for animals. Weight gain, food intake, feed efficiency ratio, weight, thickness and length of femur; retention of zinc, calcium (Ca) and magnesium (Mg) in the femur and the concentrations of Zn in femur, plasma and erythrocytes were evaluated. Control diet showed higher weight gain, feed efficiency ratio, retention of Zn and Zn concentration in the femur (p < 0.05). However, no differences were observed (p > 0.05) for dietary intake, length and thickness of the femur, erythrocyte and plasmatic Zn between groups. Although rice fortified with zinc oxide showed a lower bioavailability compared to ZnCO3, this food can be a viable alternative to be used as a vehicle for fortification. PMID:24932657

Phytohormone profile in Lactuca sativa and Brassica oleracea plants grown under Zn deficiency.

PubMed

Navarro-León, Eloy; Albacete, Alfonso; Torre-González, Alejandro de la; Ruiz, Juan M; Blasco, Begoña

2016-10-01

Phytohormones, structurally diverse compounds, are involved in multiple processes within plants, such as controlling plant growth and stress response. Zn is an essential micronutrient for plants and its deficiency causes large economic losses in crops. Therefore, the purpose of this study was to analyse the role of phytohormones in the Zn-deficiency response of two economically important species, i.e. Lactuca sativa and Brassica oleracea. For this, these two species were grown hydroponically with different Zn-application rates: 10 μM Zn as control and 0.1 μM Zn as deficiency treatment and phytohormone concentration was determined by U-HPLC-MS. Zn deficiency resulted in a substantial loss of biomass in L. sativa plants that was correlated with a decline in growth-promoting hormones such as indole-3-acetic acid (IAA), cytokinins (CKs), and gibberellins (GAs). However these hormones increased or stabilized their concentrations in B. oleracea and could help to maintain the biomass in this species. A lower concentration of stress-signaling hormones such as ethylene precursor aminocyclopropane-1-carboxylic acid (ACC), abscisic acid (ABA), salicylic acid (SA) and jasmonic acid (JA) and also CKs might be involved in Zn uptake in L. sativa while a rise in GA4, isopentenyl adenine (iP), and ACC and a fall in JA and SA might contribute to a better Zn-utilization efficiency (ZnUtE), as observed in B. oleracea plants. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of Zn Deficiency and Bicarbonate on the Growth and Photosynthetic Characteristics of Four Plant Species

PubMed Central

Zhao, Kuan; Wu, Yanyou

2017-01-01

Calcareous soils are characterized by low nutrient contents, high bicarbonate (HCO3−) content, and high alkalinity. The effects of HCO3− addition under zinc-sufficient (+Zn) and zinc-deficient (−Zn) conditions on the growth and photosynthetic characteristics of seedlings of two Moraceae species (Broussonetia papyrifera and Morus alba) and two Brassicaceae species (Orychophragmus violaceus and Brassica napus) were investigated. These four species were hydroponically grown in nutrient solution with 0 mM Zn (−Zn) or 0.02 mM Zn (+Zn) and 0 mM or 10 mM HCO3−. The photosynthetic response to HCO3− treatment, Zn deficiency, or both varied according to plant species. Of the four species, Broussonetia papyrifera showed the best adaptability to Zn deficiency for both the 0 mM and 10 mM HCO3− treatments due to its strong growth and minimal inhibition of photosynthesis and photosystem II (PS II). Brassica napus was sensitive to Zn deficiency, HCO3− treatment, or both as evidenced by the considerable inhibition of photosynthesis and high PS II activity. The results indicated different responses of various plant species to Zn deficiency and excess HCO3−. Broussonetia papyrifera was shown to have potential as a pioneer species in karst regions. PMID:28076430

A new transgenic rice line exhibiting enhanced ferric iron reduction and phytosiderophore production confers tolerance to low iron availability in calcareous soil.

PubMed

Masuda, Hiroshi; Shimochi, Erika; Hamada, Tatsuro; Senoura, Takeshi; Kobayashi, Takanori; Aung, May Sann; Ishimaru, Yasuhiro; Ogo, Yuko; Nakanishi, Hiromi; Nishizawa, Naoko K

2017-01-01

Iron (Fe) deficiency is a critical agricultural problem, especially in calcareous soil, which is distributed worldwide. Rice plants take up Fe(II) from soil through a OsIRT1 transporter (Strategy I-related system) and also take up Fe(III) via a phytosiderophore-based system (Strategy II system). However, rice plants are susceptible to low-Fe conditions because they have low Fe(III) reduction activity and low-level phytosiderophore secretion. Previously, we produced transgenic rice plants expressing a mutationally reconstructed yeast ferric chelate reductase, refre1/372, under the control of the OsIRT1 promoter. This transgenic rice line exhibited higher Fe(III) chelate reductase activity and tolerance to Fe deficiency. In addition, we produced transgenic rice overexpressing the Fe deficiency-inducible transcription factor, OsIRO2, which regulates the expression of various genes involved in the strategy II Fe(III) uptake system, including OsNAS1, OsNAAT1, OsDMAS1, OsYSL15, and TOM1. This transgenic rice exhibited improved phytosiderophore secretion ability and tolerance to Fe deficiency. In the present research, transgenic rice plants that possess both the OsIRT1 promoter-refre1/372 and the 35S promoter-OsIRO2 (RI lines) were produced to enhance both Strategy I Fe(II) reductase ability and Strategy II phytosiderophore productivity. RI lines exhibited enhanced tolerance to Fe-deficient conditions at the early and middle-late stages of growth in calcareous soil, compared to both the non-transgenic line and lines harboring either OsIRT1 promoter-refre1/372 or 35S promoter-OsIRO2 alone. RI lines also exhibited a 9-fold higher yield than the non-transgenic line. Moreover, we successfully produced Fe-deficiency-tolerant Tachisugata rice, which is a high-biomass variety used as fodder. Collectively, our results demonstrate that combined enhancement of two Fe uptake systems in rice is highly effective in conferring tolerance to low Fe availability in calcareous soil.

Zinc absorption from low phytic acid genotypes of maize (Zea mays L.), barley (Hordeum vulgare L.) and rice (Oryza sativa L.) assessed in a suckling rat pup model

USDA-ARS?s Scientific Manuscript database

Phytic acid (PA) is an inhibitor of zinc (Zn) absorption. Because dietary PA is a major causative factor for low Zn bioavailability from most diets, a reduction in the PA content of staple diets is likely to improve Zn nutrition in populations of risk of Zn deficiency. Reducing the PA content of mai...

OsWRKY74, a WRKY transcription factor, modulates tolerance to phosphate starvation in rice.

PubMed

Dai, Xiaoyan; Wang, Yuanyuan; Zhang, Wen-Hao

2016-02-01

The WRKY transcription factor family has 109 members in the rice genome, and has been reported to be involved in the regulation of biotic and abiotic stress in plants. Here, we demonstrated that a rice OsWRKY74 belonging to group III of the WRKY transcription factor family was involved in tolerance to phosphate (Pi) starvation. OsWRKY74 was localized in the nucleus and mainly expressed in roots and leaves. Overexpression of OsWRKY74 significantly enhanced tolerance to Pi starvation, whereas transgenic lines with down-regulation of OsWRKY74 were sensitive to Pi starvation. Root and shoot biomass, and phosphorus (P) concentration in rice OsWRKY74-overexpressing plants were ~16% higher than those of wild-type (WT) plants in Pi-deficient hydroponic solution. In soil pot experiments, >24% increases in tiller number, grain weight and P concentration were observed in rice OsWRKY74-overexpressing plants compared to WT plants when grown in P-deficient medium. Furthermore, Pi starvation-induced changes in root system architecture were more profound in OsWRKY74-overexpressing plants than in WT plants. Expression patterns of a number of Pi-responsive genes were altered in the OsWRKY74-overexpressing and RNA interference lines. In addition, OsWRKY74 may also be involved in the response to deficiencies in iron (Fe) and nitrogen (N) as well as cold stress in rice. In Pi-deficient conditions, OsWRKY74-overexpressing plants exhibited greater accumulation of Fe and up-regulation of the cold-responsive genes than WT plants. These findings highlight the role of OsWRKY74 in modulation of Pi homeostasis and potential crosstalk between P starvation and Fe starvation, and cold stress in rice. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Plant growth enhancing effects by a siderophore-producing endophytic streptomycete isolated from a Thai jasmine rice plant (Oryza sativa L. cv. KDML105).

PubMed

Rungin, Siriwan; Indananda, Chantra; Suttiviriya, Pavinee; Kruasuwan, Worarat; Jaemsaeng, Ratchaniwan; Thamchaipenet, Arinthip

2012-10-01

An endophytic Streptomyces sp. GMKU 3100 isolated from roots of a Thai jasmine rice plant (Oryza sativa L. cv. KDML105) showed the highest siderophore production on CAS agar while phosphate solubilization and IAA production were not detected. A mutant of Streptomyces sp. GMKU 3100 deficient in just one of the plant growth promoting traits, siderophore production, was generated by inactivation of a desD-like gene encoding a key enzyme controlling the final step of siderophore biosynthesis. Pot culture experiments revealed that rice and mungbean plants inoculated with the wild type gave the best enhancement of plant growth and significantly increased root and shoot biomass and lengths compared with untreated controls and siderophore-deficient mutant treatments. Application of the wild type in the presence or absence of ferric citrate significantly promoted plant growth of both plants. The siderophore-deficient mutant clearly showed the effect of this important trait involved in plant-microbe interaction in enhancement of growth in rice and mungbean plants supplied with sequestered iron. Our results highlight the value of a substantial understanding of the relationship of the plant growth promoting properties of endophytic actinomycetes to the plants. Endophytic actinomycetes, therefore, can be applied as potentially safe and environmentally friendly biofertilizers in agriculture.

Induction of Nickel Accumulation in Response to Zinc Deficiency in Arabidopsis thaliana

PubMed Central

Nishida, Sho; Kato, Aki; Tsuzuki, Chisato; Yoshida, Junko; Mizuno, Takafumi

2015-01-01

Excessive accumulation of nickel (Ni) can be toxic to plants. In Arabidopsis thaliana, the Fe2+ transporter, iron (Fe)-regulated transporter1 (IRT1), mediates Fe uptake and also implicates in Ni2+ uptake at roots; however, the underlying mechanism of Ni2+ uptake and accumulation remains unelucidated. In the present study, we found that zinc (Zn) deficient conditions resulted in increased accumulation of Ni in plants, particularly in roots, in A. thaliana. In order to elucidate the underlying mechanisms of Ni uptake correlating zinc condition, we traced 63Ni isotope in response to Zn and found that (i) Zn deficiency induces short-term Ni2+ absorption and (ii) Zn2+ inhibits Ni2+ uptake, suggesting competitive uptake between Ni and Zn. Furthermore, the Zrt/Irt-like protein 3 (ZIP3)-defective mutant with an elevated Zn-deficient response exhibited higher Ni accumulation than the wild type, further supporting that the response to Zn deficiency induces Ni accumulation. Previously, expression profile study demonstrated that IRT1 expression is not inducible by Zn deficiency. In the present study, we found increased Ni accumulation in IRT1-null mutant under Zn deficiency in agar culture. These suggest that Zn deficiency induces Ni accumulation in an IRT1-independen manner. The present study revealed that Ni accumulation is inducible in response to Zn deficiency, which may be attributable to a Zn uptake transporter induced by Zn deficiency. PMID:25923075

Heavy metals in wild rice from northern Wisconsin

USGS Publications Warehouse

Bennett, J.P.; Chiriboga, E.; Coleman, J.; Waller, D.M.

2000-01-01

Wild rice grain samples from various parts of the world have been found to have elevated concentrations of heavy metals, raising concern for potential effects on human health. It was hypothesized that wild rice from north-central Wisconsin could potentially have elevated concentrations of some heavy metals because of possible exposure to these elements from the atmosphere or from water and sediments. In addition, no studies of heavy metals in wild rice from Wisconsin had been performed, and a baseline study was needed for future comparisons. Wild rice plants were collected from four areas in Bayfield, Forest, Langlade, Oneida, Sawyer and Wood Counties in September, 1997 and 1998 and divided into four plant parts for elemental analyses: roots, stems, leaves and seeds. A total of 194 samples from 51 plants were analyzed across the localities, with an average of 49 samples per part depending on the element. Samples were cleaned of soil, wet digested, and analyzed by ICP for Ag, As, Cd, Cr, Cu, Hg, Mg, Pb, Se and Zn. Roots contained the highest concentrations of Ag, As, Cd, Cr, Hg, Pb, and Se. Copper was highest in both roots and seeds, while Zn was highest just in seeds. Magnesium was highest in leaves. Seed baseline ranges for the 10 elements were established using the 95% confidence intervals of the medians. Wild rice plants from northern Wisconsin had normal levels of the nutritional elements Cu, Mg and Zn in the seeds. Silver, Cd, Hg, Cr, and Se were very low in concentration or within normal limits for food plants. Arsenic and Pb, however, were elevated and could pose a problem for human health. The pathway for As, Hg and Pb to the plants could be atmospheric.

A study on zinc distribution in calcareous soils for cowpea (Vigna Unguiculata L.) and barely ( Hordeum Vulgare L.)

NASA Astrophysics Data System (ADS)

Boroomand, Naser; Maleki, Mohammad Reza

2010-05-01

Compared to other cereals, such as wheat and barley cultivars which have low sensitivity to Zn deficiency, cowpea is sensitive to zinc (Zn) deficiency, however it extensively grows even in soils with deficient in Zn. A 8-week greenhouse experiment was conducted to study the response of cowpea and barely to Zn in calcareous soils with different DTPA- Zn. The soil samples were taken from soil surface up to 0.3 m in which their DTPA- Zn ranged from 0.5 to 3.5 mg kg-1. Shoot dry matter, concentration and uptake of Zn were found to be significantly correlated with soil DTPA- Zn in cowpea and barely. Critical deficiency level of Zn in cowpea was 1.3 mg kg-1 in soil and 28.5 mg kg-1 in shoot dry matter, however, to barely symptoms of Zn deficiency was not observed and concentration of Zn was higher than the critical level reported in literatures. Organic carbon (OC), calcium carbonate equivalent (CCE), pH and field capacity soil moisture content(FC) were significantly correlated with plant responses to Zn which were the most influenced characteristics to Zn uptake by plants.

Assessment of the Phytotoxicity of Metal Oxide Nanoparticles on Two Crop Plants, Maize (Zea mays L.) and Rice (Oryza sativa L.).

PubMed

Yang, Zhongzhou; Chen, Jing; Dou, Runzhi; Gao, Xiang; Mao, Chuanbin; Wang, Li

2015-11-30

In this study, the phytotoxicity of seven metal oxide nanoparticles(NPs)-titanium dioxide (nTiO₂), silicon dioxide (nSiO₂), cerium dioxide (nCeO₂), magnetite (nFe₃O₄), aluminum oxide (nAl₂O₃), zinc oxide (nZnO) and copper oxide (nCuO)-was assessed on two agriculturally significant crop plants (maize and rice). The results showed that seed germination was not affected by any of the seven metal oxide NPs. However, at the concentration of 2000 mg·L(-1), the root elongation was significantly inhibited by nCuO (95.73% for maize and 97.28% for rice), nZnO (50.45% for maize and 66.75% for rice). On the contrary, minor phytotoxicity of nAl₂O₃ was only observed in maize, and no obvious toxic effects were found in the other four metal oxide NPs. By further study we found that the phytotoxic effects of nZnO, nAl₂O₃ and nCuO (25 to 2000 mg·L(-)¹) were concentration dependent, and were not caused by the corresponding Cu(2+), Zn(2+) and Al(3+) ions (0.11 mg·L(-)¹, 1.27 mg·L(-)¹ and 0.74 mg·L(-)¹, respectively). Furthermore, ZnO NPs (<50 nm) showed greater toxicity than ZnO microparticles(MPs)(<5 μm) to root elongation of both maize and rice. Overall, this study provided valuable information for the application of engineered NPs in agriculture and the assessment of the potential environmental risks.

Zinc stress affects ionome and metabolome in tea plants.

PubMed

Zhang, Yinfei; Wang, Yu; Ding, Zhaotang; Wang, Hui; Song, Lubin; Jia, Sisi; Ma, Dexin

2017-02-01

The research of physiological responses to Zn stress in plants has been extensively studied. However, the ionomics and metabolomics responses of plants to Zn stress remain largely unknown. In present study, the nutrient elements were identified involved in ion homeostasis and metabolomics changes related to Zn deficiency or excess in tea plants. Nutrient element analysis demonstrated that the concentrations of Zn affected the ion-uptake in roots and the nutrient element transportation to leaves, leading to the different distribution of P, S, Al, Ca, Fe and Cu in the tea leaves or roots. Metabolomics analysis revealed that Zn deficiency or excess differentially influenced the metabolic pathways in the tea leaves. More specifically, Zn deficiency affected the metabolism of carbohydrates, and Zn excess affected flavonoids metabolism. Additionally, the results showed that both Zn deficiency and Zn excess led to reduced nicotinamide levels, which speeded up NAD + degradation and thus reduced energy metabolism. Furthermore, element-metabolite correlation analysis illustrated that Zn contents in the tea leaves were positively correlated with organic acids, nitrogenous metabolites and some carbohydrate metabolites, and negatively correlated with the metabolites involved in secondary metabolism and some other carbohydrate metabolites. Meanwhile, metabolite-metabolite correlation analysis demonstrated that organic acids, sugars, amino acids and flavonoids played dominant roles in the regulation of the tea leaf metabolism under Zn stress. Therefore, the conclusion should be drawn that the tea plants responded to Zn stress by coordinating ion-uptake and regulation of metabolism of carbohydrates, nitrogenous metabolites, and flavonoids. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

An NADPH Oxidase RBOH Functions in Rice Roots during Lysigenous Aerenchyma Formation under Oxygen-Deficient Conditions

PubMed Central

Yoshioka, Miki; Fukazawa, Aya; Nishizawa, Naoko K.

2017-01-01

Reactive oxygen species (ROS) produced by the NADPH oxidase, respiratory burst oxidase homolog (RBOH), trigger signal transduction in diverse biological processes in plants. However, the functions of RBOH homologs in rice (Oryza sativa) and other gramineous plants are poorly understood. Ethylene induces the formation of lysigenous aerenchyma, which consists of internal gas spaces created by programmed cell death of cortical cells, in roots of gramineous plants under oxygen-deficient conditions. Here, we report that, in rice, one RBOH isoform (RBOHH) has a role in ethylene-induced aerenchyma formation in roots. Induction of RBOHH expression under oxygen-deficient conditions was greater in cortical cells than in cells of other root tissues. In addition, genes encoding group I calcium-dependent protein kinases (CDPK5 and CDPK13) were strongly expressed in root cortical cells. Coexpression of RBOHH with CDPK5 or CDPK13 induced ROS production in Nicotiana benthamiana leaves. Inhibitors of RBOH activity or cytosolic calcium influx suppressed ethylene-induced aerenchyma formation. Moreover, knockout of RBOHH by CRISPR/Cas9 reduced ROS accumulation and inducible aerenchyma formation in rice roots. These results suggest that RBOHH-mediated ROS production, which is stimulated by CDPK5 and/or CDPK13, is essential for ethylene-induced aerenchyma formation in rice roots under oxygen-deficient conditions. PMID:28351990

Tocopherol-deficient rice plants display increased sensitivity to photooxidative stress.

PubMed

Chen, Defu; Chen, Haiwei; Zhang, Luhua; Shi, Xiaoli; Chen, Xiwen

2014-06-01

Tocopherols are lipophilic antioxidants that are synthesized exclusively in photosynthetic organisms. Despite extensive in vivo characterization of tocopherol functions in plants, their functions in the monocot model plant, rice, remain to be determined. In this study, transgenic rice plants constitutively silenced for homogentisate phytyltransferase (HPT) and tocopherol cyclase (TC) activity were generated. Silencing of HPT and TC resulted in up to a 98 % reduction in foliar tocopherol content relative to the control plants, which was also confirmed by transcript level analysis. When grown under normal conditions, HPT and TC transgenics showed no distinctive phenotype relative to the control plants, except a slight reduction in plant height and a slight decrease in the first leaf length. However, when exposed to high light at low temperatures, HPT and TC transgenics had a significantly higher leaf yellowing index than the control plants. The tocopherol-deficient plants decreased their total individual chlorophyll levels, their chlorophyll a/b ratio, and the maximum photochemical efficiency of photosystem II, whereas increased lipid peroxidation levels relative to the control plants. Tocopherol deficiency had no effect on ascorbate biosynthesis, but induced glutathione, antheraxanthin, and particularly zeaxanthin biosynthesis for compensation under stressful conditions. However, despite these compensation mechanisms, HPT and TC transgenics still exhibited altered phenotypes under high light at low temperatures. Therefore, it is suggested that tocopherols cannot be replaced and play an indispensable role in photoprotection in rice.

Improving the nutritional value of Golden Rice through increased pro-vitamin A content.

PubMed

Paine, Jacqueline A; Shipton, Catherine A; Chaggar, Sunandha; Howells, Rhian M; Kennedy, Mike J; Vernon, Gareth; Wright, Susan Y; Hinchliffe, Edward; Adams, Jessica L; Silverstone, Aron L; Drake, Rachel

2005-04-01

"Golden Rice" is a variety of rice engineered to produce beta-carotene (pro-vitamin A) to help combat vitamin A deficiency, and it has been predicted that its contribution to alleviating vitamin A deficiency would be substantially improved through even higher beta-carotene content. We hypothesized that the daffodil gene encoding phytoene synthase (psy), one of the two genes used to develop Golden Rice, was the limiting step in beta-carotene accumulation. Through systematic testing of other plant psys, we identified a psy from maize that substantially increased carotenoid accumulation in a model plant system. We went on to develop "Golden Rice 2" introducing this psy in combination with the Erwinia uredovora carotene desaturase (crtI) used to generate the original Golden Rice. We observed an increase in total carotenoids of up to 23-fold (maximum 37 microg/g) compared to the original Golden Rice and a preferential accumulation of beta-carotene.

A rice tonoplastic calcium exchanger, OsCCX2 mediates Ca2+/cation transport in yeast

PubMed Central

Yadav, Akhilesh K.; Shankar, Alka; Jha, Saroj K.; Kanwar, Poonam; Pandey, Amita; Pandey, Girdhar K.

2015-01-01

In plant cell, cations gradient in cellular compartments is maintained by synergistic action of various exchangers, pumps and channels. The Arabidopsis exchanger family members (AtCCX3 and AtCCX5) were previously studied and belong to CaCA (calcium cation exchangers) superfamily while none of the rice CCXs has been functionally characterized for their cation transport activities till date. Rice genome encode four CCXs and only OsCCX2 transcript showed differential expression under abiotic stresses and Ca2+ starvation conditions. The OsCCX2 localized to tonoplast and suppresses the Ca2+ sensitivity of K667 (low affinity Ca2+ uptake deficient) yeast mutant under excess CaCl2 conditions. In contrast to AtCCXs, OsCCX2 expressing K667 yeast cells show tolerance towards excess Na+, Li+, Fe2+, Zn2+ and Co2+ and suggest its ability to transport both mono as well as divalent cations in yeast. Additionally, in contrast to previously characterized AtCCXs, OsCCX2 is unable to complement yeast trk1trk2 double mutant suggesting inability to transport K+ in yeast system. These finding suggest that OsCCX2 having distinct metal transport properties than previously characterized plant CCXs. OsCCX2 can be used as potential candidate for enhancing the abiotic stress tolerance in plants as well as for phytoremediation of heavy metal polluted soil. PMID:26607171

Low melatonin production by suppression of either serotonin N-acetyltransferase or N-acetylserotonin methyltransferase in rice causes seedling growth retardation with yield penalty, abiotic stress susceptibility, and enhanced coleoptile growth under anoxic conditions.

PubMed

Byeon, Yeong; Back, Kyoungwhan

2016-04-01

Serotonin N-acetyltransferase (SNAT) and N-acetylserotonin methyltransferase (ASMT) are the last two key enzymes for melatonin biosynthesis in living organisms. In this study, we demonstrated that transgenic rice (Oryza sativa L.) plants, in which expression of either endogenous SNAT or ASMT was suppressed, had reduced melatonin synthesis, confirming that both SNAT and ASMT are functionally involved in melatonin synthesis. The melatonin-deficient SNAT rice had retarded seedling growth, which was partially restored by exogenous melatonin application, suggesting melatonin's role in seedling growth. In addition, the plants were more sensitive to various abiotic stresses, including salt and cold, compared with the wild type. Melatonin-deficient SNAT rice had increased coleoptile growth under anoxic conditions, indicating that melatonin also inversely regulates plant growth under anaerobic conditions with the concomitant high expression of alcohol dehydrogenase genes. Similarly, the melatonin-deficient ASMT rice exhibited accelerated senescence in detached flag leaves, as well as significantly reduced yield. These loss-of-function studies on the melatonin biosynthetic genes confirmed most previous pharmacological reports that melatonin not only promotes plant growth but also mitigates various abiotic stresses. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Biofortified indica rice attains iron and zinc nutrition dietary targets in the field

PubMed Central

Trijatmiko, Kurniawan R.; Dueñas, Conrado; Tsakirpaloglou, Nikolaos; Torrizo, Lina; Arines, Felichi Mae; Adeva, Cheryl; Balindong, Jeanette; Oliva, Norman; Sapasap, Maria V.; Borrero, Jaime; Rey, Jessica; Francisco, Perigio; Nelson, Andy; Nakanishi, Hiromi; Lombi, Enzo; Tako, Elad; Glahn, Raymond P.; Stangoulis, James; Chadha-Mohanty, Prabhjit; Johnson, Alexander A. T.; Tohme, Joe; Barry, Gerard; Slamet-Loedin, Inez H.

2016-01-01

More than two billion people are micronutrient deficient. Polished grains of popular rice varieties have concentration of approximately 2 μg g−1 iron (Fe) and 16 μg g−1 zinc (Zn). The HarvestPlus breeding programs for biofortified rice target 13 μg g−1 Fe and 28 μg g−1 Zn to reach approximately 30% of the estimated average requirement (EAR). Reports on engineering Fe content in rice have shown an increase up to 18 μg g−1 in glasshouse settings; in contrast, under field conditions, 4 μg g−1 was the highest reported concentration. Here, we report on selected transgenic events, field evaluated in two countries, showing 15 μg g−1 Fe and 45.7 μg g−1 Zn in polished grain. Rigorous selection was applied to 1,689 IR64 transgenic events for insert cleanliness and, trait and agronomic performances. Event NASFer-274 containing rice nicotianamine synthase (OsNAS2) and soybean ferritin (SferH-1) genes showed a single locus insertion without a yield penalty or altered grain quality. Endosperm Fe and Zn enrichment was visualized by X-ray fluorescence imaging. The Caco-2 cell assay indicated that Fe is bioavailable. No harmful heavy metals were detected in the grain. The trait remained stable in different genotype backgrounds. PMID:26806528

Root Associated Bacillus sp. Improves Growth, Yield and Zinc Translocation for Basmati Rice (Oryza sativa) Varieties

PubMed Central

Shakeel, Muhammad; Rais, Afroz; Hassan, Muhammad Nadeem; Hafeez, Fauzia Yusuf

2015-01-01

Plant associated rhizobacteria prevailing in different agro-ecosystems exhibit multiple traits which could be utilized in various aspect of sustainable agriculture. Two hundred thirty four isolates were obtained from the roots of basmati-385 and basmati super rice varieties growing in clay loam and saline soil at different locations of Punjab (Pakistan). Out of 234 isolates, 27 were able to solubilize zinc (Zn) from different Zn ores like zinc phosphate [Zn3 (PO4)2], zinc carbonate (ZnCO3) and zinc oxide (ZnO). The strain SH-10 with maximum Zn solubilization zone of 24 mm on Zn3 (PO4)2ore and strain SH-17 with maximum Zn solubilization zone of 14–15 mm on ZnO and ZnCO3ores were selected for further studies. These two strains solubilized phosphorous (P) and potassium (K) in vitro with a solubilization zone of 38–46 mm and 47–55 mm respectively. The strains also suppressed economically important rice pathogens Pyricularia oryzae and Fusarium moniliforme by 22–29% and produced various biocontrol determinants in vitro. The strains enhanced Zn translocation toward grains and increased yield of basmati-385 and super basmati rice varieties by 22–49% and 18–47% respectively. The Zn solubilizing strains were identified as Bacillus sp. and Bacillus cereus by 16S rRNA gene analysis. PMID:26635754

Rice seed toxicity tests for organic and inorganic substances

USGS Publications Warehouse

Wang, W.

1994-01-01

Plant seed toxicity tests can be used to evaluate hazardous waste sites and to assess toxicity of complex effluents and industrial chemicals. Conventional plant seed toxicity tests are performed using culture dishes containing filter paper. Some reports indicate that filter papers might interfere with the toxicity of inorganic substances. In this study, a plastic seed tray was used. Rice was used as the test species. A comparison of results in the literature and this study revealed that variation of test species, methods, exposure duration, and other factors may affect the test results. The results of this study showed that the order of decreasing toxicity of metal ions was Cu>Ag>Ni>Cd>Cr(VI)>Pb>Zn>Mn>NaF for rice. The test results were similar to those reported in the literature for lettuce Ag>Ni>Cd,Cu>Cr (VI)>Zn>Mn, millet Cu,Ni>Cd>Cr(VI)>Zn>Mn, and ryegrass Cu>Ni>Mn>>Pb>Cd>Zn> Al>Hg>Cr>Fe. The order of decreasing toxicity of organic herbicides was paraquat, 2,4-D>>glyphosate>bromacil.

Effects of zinc toxicity on sugar beet (Beta vulgaris L.) plants grown in hydroponics.

PubMed

Sagardoy, R; Morales, F; López-Millán, A-F; Abadía, A; Abadía, J

2009-05-01

The effects of high Zn concentration were investigated in sugar beet (Beta vulgaris L.) plants grown in a controlled environment in hydroponics. High concentrations of Zn sulphate in the nutrient solution (50, 100 and 300 microm) decreased root and shoot fresh and dry mass, and increased root/shoot ratios, when compared to control conditions (1.2 microm Zn). Plants grown with excess Zn had inward-rolled leaf edges and a damaged and brownish root system, with short lateral roots. High Zn decreased N, Mg, K and Mn concentrations in all plant parts, whereas P and Ca concentrations increased, but only in shoots. Leaves of plants treated with 50 and 100 microm Zn developed symptoms of Fe deficiency, including decreases in Fe, chlorophyll and carotenoid concentrations, increases in carotenoid/chlorophyll and chlorophyll a/b ratios and de-epoxidation of violaxanthin cycle pigments. Plants grown with 300 microm Zn had decreased photosystem II efficiency and further growth decreases but did not have leaf Fe deficiency symptoms. Leaf Zn concentrations of plants grown with excess Zn were high but fairly constant (230-260 microg.g(-1) dry weight), whereas total Zn uptake per plant decreased markedly with high Zn supply. These data indicate that sugar beet could be a good model to investigate Zn homeostasis mechanisms in plants, but is not an efficient species for Zn phytoremediation.

Characteristics of photosynthesis and functions of the water-water cycle in rice (Oryza sativa) leaves in response to potassium deficiency.

PubMed

Weng, Xiao-Yan; Zheng, Chen-Juan; Xu, Hong-Xia; Sun, Jian-Yi

2007-12-01

The mechanisms of photoprotection of photosynthesis and dissipation of excitation energy in rice leaves in response to potassium (K) deficiency were investigated. Net photosynthetic rate and the activity of ribulose-1,5-bisphosphate carboxylase/oxygenase decreased under K deficiency. Compared with the control, non-photochemical quenching of Chl fluorescence increased in K-deficient plant, whereas the efficiency of excitation transfer (F'(v)/F'(m)) and the photochemical quenching coefficient (q(P)) decreased. Thus, thermal dissipation of excitation energy increased as more excess electrons were accumulated in the photosynthetic chain. The electron transport rate through PSII (J(f)) was more sensitive to O2 concentration, and the fraction of electron transport rate required to sustain CO2 assimilation and photorespiration (J(g)/J(f)) was significantly decreased under K deficiency compared with the control. Furthermore, the alternative electron transport (J(a)/J(f)) was increased, indicating that a considerable amount of electrons had been transported to O2 during the water-water cycle in the K-deficient leaves. Although the fraction of electron transport to photorespiration (J(o)/J(f)) was also increased in the K-deficient leaves, it was less sensitive than that of the water-water cycle. With the generation of reactive oxygen species level, the activities of superoxide dismutase and ascorbate peroxidase, two of the key enzymes involved in scavenging of active oxygen species in the water-water cycle, also increased in K-deficient rice. Therefore, it is likely that a series of photoprotective mechanisms were initiated in rice plants in response to K deficiency and the water-water cycle might be critical for protecting photosynthetic apparatus under K deficiency in rice.

Antioxidant response and carboxylate metabolism in Brassica rapa exposed to different external Zn, Ca, and Mg supply.

PubMed

Blasco, Begoña; Graham, Neil S; Broadley, Martin R

2015-03-15

Zinc (Zn), calcium (Ca), and magnesium (Mg) malnutrition are common deficiencies in many developed and developing countries, resulting in a widespread health problem. Biofortification of food crops is an agricultural strategy that can be used to increase the levels of these elements in the edible portions of crops. Deficiency or toxicity of these cations in soils reduces plant growth, crop yield, and the quality of plant foodstuff. The aim of this study was to investigate the effect of external Zn, Ca, and Mg supply on accumulation and distribution of this elements as well as antioxidant response and organic acid composition of Brassica rapa ssp. trilocularis line R-o-18. Plants were grown at low Zn (0.05 μM Zn) and high Zn (500 μM Zn), low Ca (0.4 mM) and high Ca (40 mM), and low Mg (0.2 mM), and high Mg (20 mM) to simulate deficiency and toxicity conditions. Larger shoot biomass reductions were observed under high Zn, Ca and Mg treatments, and superoxide dismutase (SOD), ascorbate peroxidase (APX), H2O2, malondialdehyde (MDA), and total ascorbate (AA) showed a marked increase in these treatments. Therefore, Brassica plants might be more sensitive to excess of these elements in the nutrient solution. The translocation factor (TF) and distribution coefficient (DC) values of Zn, Ca, and Mg indicated higher translocation and accumulation in deficient conditions. High biosynthesis and citrate content in Brassica plants may be associated mainly with a high-nutrient solution extraction ability of these plants. These results provide background data, which will be used to characterize TILLING mutants to study the effects of mutations in genes involved in regulating Zn, Ca, and Mg distribution and accumulation in plants. Copyright © 2014 Elsevier GmbH. All rights reserved.

OsPRX2 contributes to stomatal closure and improves potassium deficiency tolerance in rice.

PubMed

Mao, Xiaohui; Zheng, Yanmei; Xiao, Kaizhuan; Wei, Yidong; Zhu, Yongsheng; Cai, Qiuhua; Chen, Liping; Xie, Huaan; Zhang, Jianfu

2018-01-01

Peroxiredoxins (Prxs) which are thiol-based peroxidases have been implicated in the toxic reduction and intracellular concentration regulation of hydrogen peroxide. In Arabidopsis thaliana At2-CysPrxB (At5g06290) has been demonstrated to be essential in maintaining the water-water cycle for proper H 2 O 2 scavenging. Although the mechanisms of 2-Cys Prxs have been extensively studied in Arabidopsis thaliana, the function of 2-Cys Prxs in rice is unclear. In this study, a rice homologue gene of At2-CysPrxB, OsPRX2 was investigated aiming to characterize the effect of 2-Cys Prxs on the K + -deficiency tolerance in rice. We found that OsPRX2 was localized in the chloroplast. Overexpressed OsPRX2 causes the stomatal closing and K + -deficiency tolerance increasing, while knockout of OsPRX2 lead to serious defects in leaves phenotype and the stomatal opening under the K + -deficiency tolerance. Detection of K + accumulation, antioxidant activity of transgenic plants under the starvation of potassium, further confirmed that OsPRX2 is a potential target for engineering plants with improved potassium deficiency tolerance. Copyright © 2017 Elsevier Inc. All rights reserved.

Iron deficiency regulated OsOPT7 is essential for iron homeostasis in rice.

PubMed

Bashir, Khurram; Ishimaru, Yasuhiro; Itai, Reiko Nakanishi; Senoura, Takeshi; Takahashi, Michiko; An, Gynheung; Oikawa, Takaya; Ueda, Minoru; Sato, Aiko; Uozumi, Nobuyuki; Nakanishi, Hiromi; Nishizawa, Naoko K

2015-05-01

The molecular mechanism of iron (Fe) uptake and transport in plants are well-characterized; however, many components of Fe homeostasis remain unclear. We cloned iron-deficiency-regulated oligopeptide transporter 7 (OsOPT7) from rice. OsOPT7 localized to the plasma membrane and did not transport Fe(III)-DMA or Fe(II)-NA and GSH in Xenopus laevis oocytes. Furthermore OsOPT7 did not complement the growth of yeast fet3fet4 mutant. OsOPT7 was specifically upregulated in response to Fe-deficiency. Promoter GUS analysis revealed that OsOPT7 expresses in root tips, root vascular tissue and shoots as well as during seed development. Microarray analysis of OsOPT7 knockout 1 (opt7-1) revealed the upregulation of Fe-deficiency-responsive genes in plants grown under Fe-sufficient conditions, despite the high Fe and ferritin concentrations in shoot tissue indicating that Fe may not be available for physiological functions. Plants overexpressing OsOPT7 do not exhibit any phenotype and do not accumulate more Fe compared to wild type plants. These results indicate that OsOPT7 may be involved in Fe transport in rice.

Foliar application with nano-silicon alleviates Cd toxicity in rice seedlings.

PubMed

Wang, Shihua; Wang, Fayuan; Gao, Shuangcheng

2015-02-01

Nanofertilizers may be more effective than regular fertilizers in improving plant nutrition, enhancing nutrition use efficiency, and protecting plants from environmental stress. A hydroponic pot experiment was conducted to study the role of foliar application with 2.5 mM nano-silicon in alleviating Cd stress in rice seedlings (Oryza sativa L. cv Youyou 128) grown in solution added with or without 20 μM CdCl2. The results showed that Cd treatment decreased the growth and the contents of Mg, Fe, Zn, chlorophyll a, and glutathione (GSH), accompanied by a significant increase in Cd accumulation. However, foliar application with nano-Si improved the growth, Mg, Fe, and Zn nutrition, and the contents of chlorophyll a of the rice seedlings under Cd stress and decreased Cd accumulation and translocation of Cd from root to shoot. Cd treatment produced oxidative stress to rice seedlings indicated by a higher lipid peroxidation level (as malondialdehyde (MDA)) and higher activities of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), and a lower GSH content. However, those nano-Si-treated plants had lower MDA but higher GSH content and different antioxidant enzyme activities, indicating a higher Cd tolerance in them. The results suggested that nano-Si application alleviated Cd toxicity in rice by decreasing Cd accumulation, Cd partitioning in shoot and MDA level and by increasing content of some mineral elements (Mg, Fe, and Zn) and antioxidant capacity.

Gene expression and activity of antioxidant enzymes in rice plants, cv. BRS AG, under saline stress.

PubMed

Rossatto, Tatiana; do Amaral, Marcelo Nogueira; Benitez, Letícia Carvalho; Vighi, Isabel Lopes; Braga, Eugenia Jacira Bolacel; de Magalhães Júnior, Ariano Martins; Maia, Mara Andrade Colares; da Silva Pinto, Luciano

2017-10-01

The rice cultivar ( Oryza sativa L.) BRS AG, developed by Embrapa Clima Temperado, is the first cultivar designed for purposes other than human consumption. It may be used in ethanol production and animal feed. Different abiotic stresses negatively affect plant growth. Soil salinity is responsible for a serious reduction in productivity. Therefore, the objective of this study was to evaluate the gene expression and the activity of antioxidant enzymes (SOD, CAT, APX and GR) and identify their functions in controlling ROS levels in rice plants, cultivar BRS AG, after a saline stress period. The plants were grown in vitro with two NaCl concentrations (0 and 136 mM), collected at 10, 15 and 20 days of cultivation. The results indicated that the activity of the enzymes evaluated promotes protection against oxidative stress. Although, there was an increase of reactive oxygen species, there was no increase in MDA levels. Regarding genes encoding isoforms of antioxidant enzymes, it was observed that OsSOD3 - CU/Zn , OsSOD2 - Cu/Zn , OsSOD - Cu/Zn , OsSOD4 - Cu/Zn , OsSODCc1 - Cu/Zn , OsSOD - Fe , OsAPX1 , OsCATB and OsGR2 were the most responsive. The increase in the transcription of all genes among evaluated isoforms, except for OsAPX6 , which remained stable, contributed to the increase or the maintenance of enzyme activity. Thus, it is possible to infer that the cv. BRS AG has defense mechanisms against salt stress.

Ethylene Participates in the Regulation of Fe Deficiency Responses in Strategy I Plants and in Rice.

PubMed

Lucena, Carlos; Romera, Francisco J; García, María J; Alcántara, Esteban; Pérez-Vicente, Rafael

2015-01-01

Iron (Fe) is very abundant in most soils but its availability for plants is low, especially in calcareous soils. Plants have been divided into Strategy I and Strategy II species to acquire Fe from soils. Strategy I species apply a reduction-based uptake system which includes all higher plants except the Poaceae. Strategy II species apply a chelation-based uptake system which includes the Poaceae. To cope with Fe deficiency both type of species activate several Fe deficiency responses, mainly in their roots. These responses need to be tightly regulated to avoid Fe toxicity and to conserve energy. Their regulation is not totally understood but some hormones and signaling substances have been implicated. Several years ago it was suggested that ethylene could participate in the regulation of Fe deficiency responses in Strategy I species. In Strategy II species, the role of hormones and signaling substances has been less studied. However, in rice, traditionally considered a Strategy II species but that possesses some characteristics of Strategy I species, it has been recently shown that ethylene can also play a role in the regulation of some of its Fe deficiency responses. Here, we will review and discuss the data supporting a role for ethylene in the regulation of Fe deficiency responses in both Strategy I species and rice. In addition, we will review the data about ethylene and Fe responses related to Strategy II species. We will also discuss the results supporting the action of ethylene through different transduction pathways and its interaction with other signals, such as certain Fe-related repressive signals occurring in the phloem sap. Finally, the possible implication of ethylene in the interactions among Fe deficiency responses and the responses to other nutrient deficiencies in the plant will be addressed.

Ethylene Participates in the Regulation of Fe Deficiency Responses in Strategy I Plants and in Rice

PubMed Central

Lucena, Carlos; Romera, Francisco J.; García, María J.; Alcántara, Esteban; Pérez-Vicente, Rafael

2015-01-01

Iron (Fe) is very abundant in most soils but its availability for plants is low, especially in calcareous soils. Plants have been divided into Strategy I and Strategy II species to acquire Fe from soils. Strategy I species apply a reduction-based uptake system which includes all higher plants except the Poaceae. Strategy II species apply a chelation-based uptake system which includes the Poaceae. To cope with Fe deficiency both type of species activate several Fe deficiency responses, mainly in their roots. These responses need to be tightly regulated to avoid Fe toxicity and to conserve energy. Their regulation is not totally understood but some hormones and signaling substances have been implicated. Several years ago it was suggested that ethylene could participate in the regulation of Fe deficiency responses in Strategy I species. In Strategy II species, the role of hormones and signaling substances has been less studied. However, in rice, traditionally considered a Strategy II species but that possesses some characteristics of Strategy I species, it has been recently shown that ethylene can also play a role in the regulation of some of its Fe deficiency responses. Here, we will review and discuss the data supporting a role for ethylene in the regulation of Fe deficiency responses in both Strategy I species and rice. In addition, we will review the data about ethylene and Fe responses related to Strategy II species. We will also discuss the results supporting the action of ethylene through different transduction pathways and its interaction with other signals, such as certain Fe-related repressive signals occurring in the phloem sap. Finally, the possible implication of ethylene in the interactions among Fe deficiency responses and the responses to other nutrient deficiencies in the plant will be addressed. PMID:26640474

TOND1 confers tolerance to nitrogen deficiency in rice

PubMed Central

Zhang, Yangjun; Tan, Lubin; Zhu, Zuofeng; Yuan, Lixing; Xie, Daoxin; Sun, Chuanqing

2015-01-01

Nitrogen (N), the most important mineral nutrient for plants, is critical to agricultural production systems. N deficiency severely affects rice growth and decreases rice yields. However, excessive use of N fertilizer has caused severe pollution to agricultural and ecological environments. The necessity of breeding of crops that require lower input of N fertilizer has been recognized. Here we identified a major quantitative trait locus on chromosome 12, Tolerance Of Nitrogen Deficiency 1 (TOND1), that confers tolerance to N deficiency in the indica cultivar Teqing. Sequence verification of 75 indica and 75 japonica cultivars from 18 countries and regions demonstrated that only 27.3% of cultivars (41 indica cultivars) contain TOND1, whereas 72.7% of cultivars, including the remaining 34 indica cultivars and all 75 japonica cultivars, do not harbor the TOND1 allele. Over-expression of TOND1 increased the tolerance to N deficiency in the TOND1-deficient rice cultivars. The identification of TOND1 provides a molecular basis for breeding rice varieties with improved grain yield despite decreased input of N fertilizers. PMID:25439309

Copper and ectopic expression of the Arabidopsis transport protein COPT1 alter iron homeostasis in rice (Oryza sativa L.).

PubMed

Andrés-Bordería, Amparo; Andrés, Fernando; Garcia-Molina, Antoni; Perea-García, Ana; Domingo, Concha; Puig, Sergi; Peñarrubia, Lola

2017-09-01

Copper deficiency and excess differentially affect iron homeostasis in rice and overexpression of the Arabidopsis high-affinity copper transporter COPT1 slightly increases endogenous iron concentration in rice grains. Higher plants have developed sophisticated mechanisms to efficiently acquire and use micronutrients such as copper and iron. However, the molecular mechanisms underlying the interaction between both metals remain poorly understood. In the present work, we study the effects produced on iron homeostasis by a wide range of copper concentrations in the growth media and by altered copper transport in Oryza sativa plants. Gene expression profiles in rice seedlings grown under copper excess show an altered expression of genes involved in iron homeostasis compared to standard control conditions. Thus, ferritin OsFER2 and ferredoxin OsFd1 mRNAs are down-regulated whereas the transcriptional iron regulator OsIRO2 and the nicotianamine synthase OsNAS2 mRNAs rise under copper excess. As expected, the expression of OsCOPT1, which encodes a high-affinity copper transport protein, as well as other copper-deficiency markers are down-regulated by copper. Furthermore, we show that Arabidopsis COPT1 overexpression (C1 OE ) in rice causes root shortening in high copper conditions and under iron deficiency. C1 OE rice plants modify the expression of the putative iron-sensing factors OsHRZ1 and OsHRZ2 and enhance the expression of OsIRO2 under copper excess, which suggests a role of copper transport in iron signaling. Importantly, the C1 OE rice plants grown on soil contain higher endogenous iron concentration than wild-type plants in both brown and white grains. Collectively, these results highlight the effects of rice copper status on iron homeostasis, which should be considered to obtain crops with optimized nutrient concentrations in edible parts.

Elemental analysis of different varieties of rice samples using XRF technique

NASA Astrophysics Data System (ADS)

Kaur, Jaspreet; Kumar, Anil

2016-05-01

Rice is most consumed staple food in the world providing over 21% of the calorie intake of world's population having high yielding capacity. Elements detected in rice are Al, As, Br, Cd, Cl, Co, Cs, Cu, Fe, Hg, K, Mg, Mn, Mo, Rb, Se and Zn by using Instrumental Neutron Activation with k0 standardization (R. Jayasekera etal,2004). Some of these trace elements are C, H, O, N, S, Ca, P, K, Na, Cl, Mn, Ti, Mg, Cu, Fe, Ni, Si and Zn are essential for growth of human physique The deficiency or excess of these elements in food is known to cause a variety of malnutrition or health disorders in the world. Every year, various varieties of rice are launched by Punjab Agriculture University, Ludhiana. The main purpose of which is to increases the yield to attain the maximum profit. But this leads to changing the elemental concentration in them, which may affect the human health according to variation in the nutrition values. The main objective is to study the presence of elemental concentration in various varieties of rice using EDXRF technique.

Heavy metals in rice and garden vegetables and their potential health risks to inhabitants in the vicinity of an industrial zone in Jiangsu, China.

PubMed

Cao, Hongbin; Chen, Jianjiang; Zhang, Jun; Zhang, Hui; Qiao, Li; Men, Yi

2010-01-01

Contamination of soil and agricultural products by heavy metals resulting from rapid industrial development has caused major concern. In this study, we investigated heavy metal (Cu, Zn, Pb, Cr, Hg and Cd) concentrations in rice and garden vegetables, as well as in cultivated soils, in a rural-industrial developed region in southern Jiangsu, China, and estimated the potential health risks of metals to the inhabitants via consumption of locally produced rice and garden vegetables. A questionnaire-based survey on dietary consumption rates of foodstuffs showed that rice and vegetables accounted for 64% of total foodstuffs consumed, and over 60% of rice and vegetables were grown in the local region. Average concentrations of Cr, Cu, Zn, Cd, Hg and Pb were 0.75, 2.64, 12.00, 0.014, 0.006 and 0.054 mg/kg dw (dry weight) in rice and were 0.67, 1.18, 4.34, 0.011, 0.002 and 0.058 mg/kg fw (fresh weight) in garden vegetables, respectively. These values were all below the maximum allowable concentration in food in China except for Cr in vegetables. Leafy vegetables had higher metal concentrations than solanaceae vegetables. Average daily intake of Cr, Cu, Zn, Cd, Hg and Pb through the consumption of rice and garden vegetables were 5.66, 16.90, 74.21, 0.10, 0.04 and 0.43 microg/(kg x day), respectively. Although Hazard Quotient values of individual metals were all lower than 1, when all six metal intakes via self-planted rice and garden vegetables were combined, the Hazard Index value was close to 1. Potential health risks from exposure to heavy metals in self-planted rice and garden vegetables need more attention.

Overexpression of a glyoxalase gene, OsGly I, improves abiotic stress tolerance and grain yield in rice (Oryza sativa L.).

PubMed

Zeng, Zhengming; Xiong, Fangjie; Yu, Xiaohong; Gong, Xiaoping; Luo, Juntao; Jiang, Yudong; Kuang, Haochi; Gao, Bijun; Niu, Xiangli; Liu, Yongsheng

2016-12-01

Glyoxalase I (Gly I) is a component of the glyoxalase system which is involved in the detoxification of methylglyoxal, a byproduct of glycolysis. In the present study, a gene of rice (Oryza sativa L., cv. Nipponbare) encoding Gly I was cloned and characterized. The quantitative real-time PCR analysis indicated that rice Gly I (OsGly I) was ubiquitously expressed in root, stem, leaf, leaf sheath and spikelet with varying abundance. OsGly I was markedly upregulated in response to NaCl, ZnCl 2 and mannitol in rice seedlings. For further functional investigation, OsGly I was overexpressed in rice using Agrobacterium-mediated transformation. Transgenic rice lines exhibited increased glyoxalase enzyme activity, decreased methylglyoxal level and improved tolerance to NaCl, ZnCl 2 and mannitol compared to wild-type plants. Enhancement of stress tolerance in transgenic lines was associated with reduction of malondialdehyde content which was derived from cellular lipid peroxidation. In addition, the OsGly I-overexpression transgenic plants performed higher seed setting rate and yield. Collectively, these results indicate the potential of bioengineering the Gly I gene in crops. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Heavy Metals Induce Iron Deficiency Responses at Different Hierarchic and Regulatory Levels.

PubMed

Lešková, Alexandra; Giehl, Ricardo F H; Hartmann, Anja; Fargašová, Agáta; von Wirén, Nicolaus

2017-07-01

In plants, the excess of several heavy metals mimics iron (Fe) deficiency-induced chlorosis, indicating a disturbance in Fe homeostasis. To examine the level at which heavy metals interfere with Fe deficiency responses, we carried out an in-depth characterization of Fe-related physiological, regulatory, and morphological responses in Arabidopsis ( Arabidopsis thaliana ) exposed to heavy metals. Enhanced zinc (Zn) uptake closely mimicked Fe deficiency by leading to low chlorophyll but high ferric-chelate reductase activity and coumarin release. These responses were not caused by Zn-inhibited Fe uptake via IRON-REGULATED TRANSPORTER (IRT1). Instead, Zn simulated the transcriptional response of typical Fe-regulated genes, indicating that Zn affects Fe homeostasis at the level of Fe sensing. Excess supplies of cobalt and nickel altered root traits in a different way from Fe deficiency, inducing only transient Fe deficiency responses, which were characterized by a lack of induction of the ethylene pathway. Cadmium showed a rather inconsistent influence on Fe deficiency responses at multiple levels. By contrast, manganese evoked weak Fe deficiency responses in wild-type plants but strongly exacerbated chlorosis in irt1 plants, indicating that manganese antagonized Fe mainly at the level of transport. These results show that the investigated heavy metals modulate Fe deficiency responses at different hierarchic and regulatory levels and that the interaction of metals with physiological and morphological Fe deficiency responses is uncoupled. Thus, this study not only emphasizes the importance of assessing heavy metal toxicities at multiple levels but also provides a new perspective on how Fe deficiency contributes to the toxic action of individual heavy metals. © 2017 American Society of Plant Biologists. All Rights Reserved.

Ascorbic acid deficiency leads to increased grain chalkiness in transgenic rice for suppressed of L-GalLDH.

PubMed

Yu, Le; Liu, Yonghai; Lu, Lina; Zhang, Qilei; Chen, Yezheng; Zhou, Liping; Chen, Hua; Peng, Changlian

2017-04-01

The grain chalkiness of rice (Oryza sativa L.), which determines the rice quality and price, is a major concern in rice breeding. Reactive oxygen species (ROS) plays a critical role in regulating rice endosperm chalkiness. Ascorbic acid (Asc) is a major plant antioxidant, which strictly regulates the levels of ROS. l-galactono-1, 4-lactone dehydrogenase (L-GalLDH, EC 1.3.2.3) is an enzyme that catalyzes the last step of Asc biosynthesis in higher plants. Here we show that the L-GalLDH-suppressed transgenic rice, GI-1 and GI-2, which have constitutively low (between 30% and 50%) leaf and grain Asc content compared with the wild-type (WT), exhibit significantly increased grain chalkiness. Further examination showed that the deficiency of Asc resulted in a higher lipid peroxidation and H 2 O 2 content, accompanied by a lower hydroxyl radical scavenging rate, total antioxidant capacity and photosynthetic ability. In addition, changes of the enzyme activities and gene transcript abundances related to starch synthesis were also observed in GI-1 and GI-2 grains. The results we presented here suggest a close correlation between Asc deficiency and grain chalkiness in the L-GalLDH-suppressed transgenics. Asc deficiency leads to the accumulation of H 2 O 2 , affecting antioxidant capacity and photosynthetic function, changing enzyme activities and gene transcript abundances related to starch synthesis, finally leading to the increased grain chalkiness. Copyright © 2017 Elsevier GmbH. All rights reserved.

Heavy Metals Induce Iron Deficiency Responses at Different Hierarchic and Regulatory Levels1[OPEN

PubMed Central

2017-01-01

In plants, the excess of several heavy metals mimics iron (Fe) deficiency-induced chlorosis, indicating a disturbance in Fe homeostasis. To examine the level at which heavy metals interfere with Fe deficiency responses, we carried out an in-depth characterization of Fe-related physiological, regulatory, and morphological responses in Arabidopsis (Arabidopsis thaliana) exposed to heavy metals. Enhanced zinc (Zn) uptake closely mimicked Fe deficiency by leading to low chlorophyll but high ferric-chelate reductase activity and coumarin release. These responses were not caused by Zn-inhibited Fe uptake via IRON-REGULATED TRANSPORTER (IRT1). Instead, Zn simulated the transcriptional response of typical Fe-regulated genes, indicating that Zn affects Fe homeostasis at the level of Fe sensing. Excess supplies of cobalt and nickel altered root traits in a different way from Fe deficiency, inducing only transient Fe deficiency responses, which were characterized by a lack of induction of the ethylene pathway. Cadmium showed a rather inconsistent influence on Fe deficiency responses at multiple levels. By contrast, manganese evoked weak Fe deficiency responses in wild-type plants but strongly exacerbated chlorosis in irt1 plants, indicating that manganese antagonized Fe mainly at the level of transport. These results show that the investigated heavy metals modulate Fe deficiency responses at different hierarchic and regulatory levels and that the interaction of metals with physiological and morphological Fe deficiency responses is uncoupled. Thus, this study not only emphasizes the importance of assessing heavy metal toxicities at multiple levels but also provides a new perspective on how Fe deficiency contributes to the toxic action of individual heavy metals. PMID:28500270

Elemental analysis of different varieties of rice samples using XRF technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaur, Jaspreet, E-mail: gillpreet05051812@gmail.com; Kumar, Anil, E-mail: gilljaspreet06@gmail.com

Rice is most consumed staple food in the world providing over 21% of the calorie intake of world’s population having high yielding capacity. Elements detected in rice are Al, As, Br, Cd, Cl, Co, Cs, Cu, Fe, Hg, K, Mg, Mn, Mo, Rb, Se and Zn by using Instrumental Neutron Activation with k0 standardization (R. Jayasekera etal,2004). Some of these trace elements are C, H, O, N, S, Ca, P, K, Na, Cl, Mn, Ti, Mg, Cu, Fe, Ni, Si and Zn are essential for growth of human physique The deficiency or excess of these elements in food is knownmore » to cause a variety of malnutrition or health disorders in the world. Every year, various varieties of rice are launched by Punjab Agriculture University, Ludhiana. The main purpose of which is to increases the yield to attain the maximum profit. But this leads to changing the elemental concentration in them, which may affect the human health according to variation in the nutrition values. The main objective is to study the presence of elemental concentration in various varieties of rice using EDXRF technique.« less

Vitamin B1 Functions as an Activator of Plant Disease Resistance1

PubMed Central

Ahn, Il-Pyung; Kim, Soonok; Lee, Yong-Hwan

2005-01-01

Vitamin B1 (thiamine) is an essential nutrient for humans. Vitamin B1 deficiency causes beriberi, which disturbs the central nervous and circulatory systems. In countries in which rice (Oryza sativa) is a major food, thiamine deficiency is prevalent because polishing of rice removes most of the thiamine in the grain. We demonstrate here that thiamine, in addition to its nutritional value, induces systemic acquired resistance (SAR) in plants. Thiamine-treated rice, Arabidopsis (Arabidopsis thaliana), and vegetable crop plants showed resistance to fungal, bacterial, and viral infections. Thiamine treatment induces the transient expression of pathogenesis-related (PR) genes in rice and other plants. In addition, thiamine treatment potentiates stronger and more rapid PR gene expression and the up-regulation of protein kinase C activity. The effects of thiamine on disease resistance and defense-related gene expression mobilize systemically throughout the plant and last for more than 15 d after treatment. Treatment of Arabidopsis ecotype Columbia-0 plants with thiamine resulted in the activation of PR-1 but not PDF1.2. Furthermore, thiamine prevented bacterial infection in Arabidopsis mutants insensitive to jasmonic acid or ethylene but not in mutants impaired in the SAR transduction pathway. These results clearly demonstrate that thiamine induces SAR in plants through the salicylic acid and Ca2+-related signaling pathways. The findings provide a novel paradigm for developing alternative strategies for the control of plant diseases. PMID:15980201

Phytochelatin Synthesis Promotes Leaf Zn Accumulation of Arabidopsis thaliana Plants Grown in Soil with Adequate Zn Supply and is Essential for Survival on Zn-Contaminated Soil.

PubMed

Kühnlenz, Tanja; Hofmann, Christian; Uraguchi, Shimpei; Schmidt, Holger; Schempp, Stefanie; Weber, Michael; Lahner, Brett; Salt, David E; Clemens, Stephan

2016-11-01

Phytochelatin (PC) synthesis is essential for the detoxification of non-essential metals such as cadmium (Cd). In vitro experiments with Arabidopsis thaliana seedlings had indicated a contribution to zinc (Zn) tolerance as well. We addressed the physiological role of PC synthesis in Zn homeostasis of plants under more natural conditions. Growth responses, PC accumulation and leaf ionomes of wild-type and AtPCS1 mutant plants cultivated in different soils representing adequate Zn supply, Zn deficiency and Zn excess were analyzed. Growth on Zn-contaminated soil triggers PC synthesis and is strongly impaired in PC-deficient mutants. In fact, the contribution of AtPCS1 to tolerating Zn excess is comparable with that of the major Zn tolerance factor MTP1. For plants supplied with a normal level of Zn, a significant reduction in leaf Zn accumulation of AtPCS1 mutants was detected. In contrast, AtPCS1 mutants grown under Zn-limited conditions showed wild-type levels of Zn accumulation, suggesting the operation of distinct Zn translocation pathways. Contrasting phenotypes of the tested AtPCS1 mutant alleles upon growth in Zn- or Cd-contaminated soil indicated differential activation of PC synthesis by these metals. Experiments with truncated versions identified a part of the AtPCS1 protein required for the activation by Zn but not by Cd. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Getting a sense for signals: regulation of the plant iron deficiency response

PubMed Central

Hindt, Maria N.; Guerinot, Mary Lou

2014-01-01

Understanding the Fe deficiency response in plants is necessary for improving both plant health and the human diet, which relies on Fe from plant sources. In this review we focus on the regulation of the two major strategies for iron acquisition in plants, exemplified by the model plants Arabidopsis and rice. Critical to our knowledge of Fe homeostasis in plants is determining how Fe is sensed and how this signal is transmitted and integrated into a response. We will explore the evidence for an Fe sensor in plants and summarize the recent findings on hormones and signaling molecules which contribute to the Fe deficiency response. PMID:22483849

Jasmonate signaling is activated in the very early stages of iron deficiency responses in rice roots.

PubMed

Kobayashi, Takanori; Itai, Reiko Nakanishi; Senoura, Takeshi; Oikawa, Takaya; Ishimaru, Yasuhiro; Ueda, Minoru; Nakanishi, Hiromi; Nishizawa, Naoko K

2016-07-01

Under low iron availability, plants induce the expression of various genes involved in iron uptake and translocation at the transcriptional level. This iron deficiency response is affected by various plant hormones, but the roles of jasmonates in this response are not well-known. We investigated the involvement of jasmonates in rice iron deficiency responses. High rates of jasmonate-inducible genes were induced during the very early stages of iron deficiency treatment in rice roots. Many jasmonate-inducible genes were also negatively regulated by the ubiquitin ligases OsHRZ1 and OsHRZ2 and positively regulated by the transcription factor IDEF1. Ten out of 35 genes involved in jasmonate biosynthesis and signaling were rapidly induced at 3 h of iron deficiency treatment, and this induction preceded that of known iron deficiency-inducible genes involved in iron uptake and translocation. Twelve genes involved in jasmonate biosynthesis and signaling were also upregulated in HRZ-knockdown roots. Endogenous concentrations of jasmonic acid and jasmonoyl isoleucine tended to be rapidly increased in roots in response to iron deficiency treatment, whereas these concentrations were higher in HRZ-knockdown roots under iron-sufficient conditions. Analysis of the jasmonate-deficient cpm2 mutant revealed that jasmonates repress the expression of many iron deficiency-inducible genes involved in iron uptake and translocation under iron sufficiency, but this repression is partly canceled under an early stage of iron deficiency. These results indicate that jasmonate signaling is activated during the very early stages of iron deficiency, which is partly regulated by IDEF1 and OsHRZs.

Facilitated citrate-dependent iron translocation increases rice endosperm iron and zinc concentrations.

PubMed

Wu, Ting-Ying; Gruissem, Wilhelm; Bhullar, Navreet K

2018-05-01

Iron deficiency affects one third of the world population. Most iron biofortification strategies have focused on genes involved in iron uptake and storage but facilitating internal long-distance iron translocation has been understudied for increasing grain iron concentrations. Citrate is a primary iron chelator, and the transporter FERRIC REDUCTASE DEFECTIVE 3 (FRD3) loads citrate into the xylem. We have expressed AtFRD3 in combination with AtNAS1 (NICOTIANAMINE SYNTHASE 1) and PvFER (FERRITIN) or with PvFER alone to facilitate long-distance iron transport together with efficient iron uptake and storage in the rice endosperm. The citrate and iron concentrations in the xylem sap of transgenic plants increased two-fold compared to control plants. Iron and zinc levels increased significantly in polished and unpolished rice grains to more than 70% of the recommended estimated average requirement (EAR) for iron and 140% of the recommended EAR for zinc in polished rice grains. Furthermore, the transformed lines showed normal phenotypic growth, were tolerant to iron deficiency and aluminum toxicity, and had grain cadmium levels similar to control plants. Together, our results demonstrate that deploying FRD for iron biofortification has no obvious anti-nutritive effects and should be considered as an effective strategy for reducing human iron deficiency anemia. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

[Effect of different organic fertilizers on bioavailability of soil Cd and Zn].

PubMed

Xie, Yun-he; Ji, Xiong-hui; Wu, Jia-mei; Huang, Juan; Guan, Di; Zhu, Jian

2015-03-01

The active effect of soil Cd and Zn and their interaction was studied in typical paddy field in south China by monitoring the contents of Cd and Zn in soil and rice in rice fields applied with pig manure, chicken manure or rice straw for 4 years continuously. The results showed that applying pig manure, chicken manure or rice straw had no significant impact on the soil total Cd content, soil available Cd content and soil Cd activity, but tended to increase the soil total Cd content and increased the soil total Zn content, soil available Zn content and Zn activity significantly. Applications of pig manure, chicken manure and rice straw all reduced the Cd content of brown rice, in order of pig manure > chicken manure > rice straw. The Cd contents of brown rice, stem and leaf in the treatment applied with pig manure were lower than in the control by 37.5%, 44.0% and 36.4%, respectively; the Cd contents of brown rice, stem and leaf in the treatment applied with chicken manure were lower than in the control by 22.5%, 33.8%, and 22.7%, respectively; the Cd content of brown rice in the treatment applied with rice straw was lower than in the control by 7.5% but its contents in stem and leaf increased by 8.2% and 22.7% , respectively. The reduction in the brown rice Cd content was mainly due to the reduction of Cd enrichment from soil to brown rice after application of pig or chicken manure, but mainly due to the reduction of Cd transportation from stem to brown rice after straw application. Applications of pig manure, chicken manure and rice straw increased Zn contents in rice stem by 53.4%, 53.4% and 13.9%, respectively, but all had no significant effect on brown rice and leaf' s Zn contents. Zn and Cd had the significant antagonistic effects in the soil and rice stem. The increase of Zn content in soil and rice stem inhibited the adsorption and accumulation of Cd in the brown rice, stem and leaf significantly, and with the increase of the proportion of Zn/Cd, the competitive absorption between Cd and Zn by rice was the main control factor affecting the Cd absorption by rice than their competitive adsorption by soil.

Solubilisation of Phosphate and Micronutrients by Trichoderma harzianum and Its Relationship with the Promotion of Tomato Plant Growth

PubMed Central

Pang, Guan; Shen, Qi-Rong; Li, Rong; Chen, Wei

2015-01-01

Trichoderma harzianum strain SQR-T037 is a biocontrol agent that has been shown to enhance the uptake of nutrients (macro- and microelements) by plants in fields. The objective of this study was to investigate the contribution of SQR-T037 to P and microelement (Fe, Mn, Cu and Zn) nutrition in tomato plants grown in soil and in hydroponic conditions. Inoculation with SQR-T037 significantly improved the biomass and nutrient uptake of tomato seedlings grown in a nutrient-limiting soil. So we investigated the capability of SQR-T037 to solubilise sparingly soluble minerals in vitro via four known mechanisms: acidification by organic acids, chelation by siderophores, redox by ferric reductase and hydrolysis by phytase. SQR-T037 was able to solubilise phytate, Fe2O3, CuO, and metallic Zn but not Ca3(PO4)2 or MnO2. Organic acids, including lactic acid, citric acid, tartaric acid and succinic acid, were detected by HPLC and LC/MS in two Trichoderma cultures. Additionally, we inoculated tomato seedlings with SQR-T037 using a hydroponic system with specific nutrient deficiencies (i.e., nutrient solutions deficient in P, Fe, Cu or Zn and supplemented with their corresponding solid minerals) to better study the effects of Trichoderma inoculation on plant growth and nutrition. Inoculated seedlings grown in Cu-deficient hydroponic conditions exhibited increases in dry plant biomass (92%) and Cu uptake (42%) relative to control plants. However, we did not observe a significant effect on seedling biomass in plants grown in the Fe- and Zn-deficient hydroponic conditions; by contrast, the biomass decreased by 82% in the P-deficient hydroponic condition. Thus, we demonstrated that Trichoderma SQR-T037 competed for P (phytate) and Zn with tomato seedlings by suppressing root development, releasing phytase and/or chelating minerals. The results of this study suggest that the induction of increased or suppressed plant growth occurs through the direct effect of T. harzianum on root development, in combination with indirect mechanisms, such as mineral solubilisation (including solubilisation via acidification, redox, chelation and hydrolysis). PMID:26110536

Solubilisation of Phosphate and Micronutrients by Trichoderma harzianum and Its Relationship with the Promotion of Tomato Plant Growth.

PubMed

Li, Rui-Xia; Cai, Feng; Pang, Guan; Shen, Qi-Rong; Li, Rong; Chen, Wei

2015-01-01

Trichoderma harzianum strain SQR-T037 is a biocontrol agent that has been shown to enhance the uptake of nutrients (macro- and microelements) by plants in fields. The objective of this study was to investigate the contribution of SQR-T037 to P and microelement (Fe, Mn, Cu and Zn) nutrition in tomato plants grown in soil and in hydroponic conditions. Inoculation with SQR-T037 significantly improved the biomass and nutrient uptake of tomato seedlings grown in a nutrient-limiting soil. So we investigated the capability of SQR-T037 to solubilise sparingly soluble minerals in vitro via four known mechanisms: acidification by organic acids, chelation by siderophores, redox by ferric reductase and hydrolysis by phytase. SQR-T037 was able to solubilise phytate, Fe2O3, CuO, and metallic Zn but not Ca3(PO4)2 or MnO2. Organic acids, including lactic acid, citric acid, tartaric acid and succinic acid, were detected by HPLC and LC/MS in two Trichoderma cultures. Additionally, we inoculated tomato seedlings with SQR-T037 using a hydroponic system with specific nutrient deficiencies (i.e., nutrient solutions deficient in P, Fe, Cu or Zn and supplemented with their corresponding solid minerals) to better study the effects of Trichoderma inoculation on plant growth and nutrition. Inoculated seedlings grown in Cu-deficient hydroponic conditions exhibited increases in dry plant biomass (92%) and Cu uptake (42%) relative to control plants. However, we did not observe a significant effect on seedling biomass in plants grown in the Fe- and Zn-deficient hydroponic conditions; by contrast, the biomass decreased by 82% in the P-deficient hydroponic condition. Thus, we demonstrated that Trichoderma SQR-T037 competed for P (phytate) and Zn with tomato seedlings by suppressing root development, releasing phytase and/or chelating minerals. The results of this study suggest that the induction of increased or suppressed plant growth occurs through the direct effect of T. harzianum on root development, in combination with indirect mechanisms, such as mineral solubilisation (including solubilisation via acidification, redox, chelation and hydrolysis).

Risk Assessment of Heavy Metals Contamination in Paddy Soil, Plants, and Grains (Oryza sativa L.) at the East Coast of India

PubMed Central

Satpathy, Deepmala; Reddy, M. Vikram; Dhal, Soumya Prakash

2014-01-01

Heavy metals known to be accumulated in plants adversely affect human health. This study aims to assess the effects of agrochemicals especially chemical fertilizers applied in paddy fields, which release potential toxic heavy metals into soil. Those heavy metals get accumulated in different parts of paddy plant (Oryza sativa L.) including the grains. Concentrations of nonessential toxic heavy metals (Cd, Cr, and Pb) and the micronutrients (Cu, Mn, and Zn) were measured in the paddy field soil and plant parts. Mn and Cd are found to be accumulated more in shoot than in root. The metal transfer factors from soil to rice plant were significant for Pb, Cd, Cu, Cr, Mn, and Zn. The ranking order of bioaccumulation factor (BAF) for heavy metals was Zn > Mn > Cd > Cu > Cr > Pb indicating that the accumulation of micronutrients was more than that of nonessential toxic heavy metals. The concentrations of heavy metals were found to be higher in paddy field soils than that of the nearby control soil but below permissible limits. The higher Health Index (HI) values of rice consuming adults (1.561) and children (1.360) suggest their adverse health effects in the near future. PMID:24995308

UV Radiation–Sensitive Norin 1 Rice Contains Defective Cyclobutane Pyrimidine Dimer Photolyase

PubMed Central

Hidema, Jun; Kumagai, Tadashi; Sutherland, Betsy M.

2000-01-01

Norin 1, a progenitor of many economically important Japanese rice strains, is highly sensitive to the damaging effects of UVB radiation (wavelengths 290 to 320 nm). Norin 1 seedlings are deficient in photorepair of cyclobutane pyrimidine dimers. However, the molecular origin of this deficiency was not known and, because rice photolyase genes have not been cloned and sequenced, could not be determined by examining photolyase structural genes or upstream regulatory elements for mutations. We therefore used a photoflash approach, which showed that the deficiency in photorepair in vivo resulted from a functionally altered photolyase. These results were confirmed by studies with extracts, which showed that the Norin 1 photolyase–dimer complex was highly thermolabile relative to the wild-type Sasanishiki photolyase. This deficiency results from a structure/function alteration of photolyase rather than of nonspecific repair, photolytic, or regulatory elements. Thus, the molecular origin of this plant DNA repair deficiency, resulting from a spontaneously occurring mutation to UV radiation sensitivity, is defective photolyase. PMID:11006332

γ-Aminobutyric acid addition alleviates ammonium toxicity by limiting ammonium accumulation in rice (Oryza sativa) seedlings.

PubMed

Ma, Xiaoling; Zhu, Changhua; Yang, Na; Gan, Lijun; Xia, Kai

2016-12-01

Excessive use of nitrogen (N) fertilizer has increased ammonium (NH 4 + ) accumulation in many paddy soils to levels that reduce rice vegetative biomass and yield. Based on studies of NH 4 + toxicity in rice (Oryza sativa, Nanjing 44) seedlings cultured in agar medium, we found that NH 4 + concentrations above 0.75 mM inhibited the growth of rice and caused NH 4 + accumulation in both shoots and roots. Use of excessive NH 4 + also induced rhizosphere acidification and inhibited the absorption of K, Ca, Mg, Fe and Zn in rice seedlings. Under excessive NH 4 + conditions, exogenous γ-aminobutyric acid (GABA) treatment limited NH 4 + accumulation in rice seedlings, reduced NH 4 + toxicity symptoms and promoted plant growth. GABA addition also reduced rhizosphere acidification and alleviated the inhibition of Ca, Mg, Fe and Zn absorption caused by excessive NH 4 + . Furthermore, we found that the activity of glutamine synthetase/NADH-glutamate synthase (GS; EC 6.3.1.2/NADH-GOGAT; EC1.4.1.14) in root increased gradually as the NH 4 + concentration increased. However, when the concentration of NH 4 + is more than 3 mM, GABA treatment inhibited NH 4 + -induced increases in GS/NADH-GOGAT activity. The inhibition of ammonium assimilation may restore the elongation of seminal rice roots repressed by high NH 4 + . These results suggest that mitigation of ammonium accumulation and assimilation is essential for GABA-dependent alleviation of ammonium toxicity in rice seedlings. © 2016 Scandinavian Plant Physiology Society.

Is there a strategy I iron uptake mechanism in maize?

PubMed

Li, Suzhen; Zhou, Xiaojin; Chen, Jingtang; Chen, Rumei

2018-04-03

Iron is a metal micronutrient that is essential for plant growth and development. Graminaceous and nongraminaceous plants have evolved different mechanisms to mediate Fe uptake. Generally, strategy I is used by nongraminaceous plants like Arabidopsis, while graminaceous plants, such as rice, barley, and maize, are considered to use strategy II Fe uptake. Upon the functional characterization of OsIRT1 and OsIRT2 in rice, it was suggested that rice, as an exceptional graminaceous plant, utilizes both strategy I and strategy II Fe uptake systems. Similarly, ZmIRT1 and ZmZIP3 were identified as functional zinc and iron transporters in the maize genome, along with the determination of several genes encoding Zn and Fe transporters, raising the possibility that strategy I Fe uptake also occurs in maize. This mini-review integrates previous reports and recent evidence to obtain a better understanding of the mechanisms of Fe uptake in maize.

Rice early flowering1, a CKI, phosphorylates DELLA protein SLR1 to negatively regulate gibberellin signalling.

PubMed

Dai, Cheng; Xue, Hong-Wei

2010-06-02

The plant hormone gibberellin (GA) is crucial for multiple aspects of plant growth and development. To study the relevant regulatory mechanisms, we isolated a rice mutant earlier flowering1, el1, which is deficient in a casein kinase I that has critical roles in both plants and animals. el1 had an enhanced GA response, consistent with the suppression of EL1 expression by exogenous GA(3). Biochemical characterization showed that EL1 specifically phosphorylates the rice DELLA protein SLR1, proving a direct evidence for SLR1 phosphorylation. Overexpression of SLR1 in wild-type plants caused a severe dwarf phenotype, which was significantly suppressed by EL1 deficiency, indicating the negative effect of SLR1 on GA signalling requires the EL1 function. Further studies showed that the phosphorylation of SLR1 is important for maintaining its activity and stability, and mutation of the candidate phosphorylation site of SLR1 results in the altered GA signalling. This study shows EL1 a novel and key regulator of the GA response and provided important clues on casein kinase I activities in GA signalling and plant development.

Expression of the ZNT1 Zinc Transporter from the Metal Hyperaccumulator Noccaea caerulescens Confers Enhanced Zinc and Cadmium Tolerance and Accumulation to Arabidopsis thaliana

PubMed Central

Schat, Henk; Aarts, Mark G. M.

2016-01-01

Prompt regulation of transition metal transporters is crucial for plant zinc homeostasis. NcZNT1 is one of such transporters, found in the metal hyperaccumulator Brassicaceae species Noccaea caerulescens. It is orthologous to AtZIP4 from Arabidopsis thaliana, an important actor in Zn homeostasis. We examined if the NcZNT1 function contributes to the metal hyperaccumulation of N. caerulescens. NcZNT1 was found to be a plasma-membrane located metal transporter. Constitutive overexpression of NcZNT1 in A. thaliana conferred enhanced tolerance to exposure to excess Zn and Cd supply, as well as increased accumulation of Zn and Cd and induction of the Fe deficiency response, when compared to non-transformed wild-type plants. Promoters of both genes were induced by Zn deficiency in roots and shoots of A. thaliana. In A. thaliana, the AtZIP4 and NcZNT1 promoters were mainly active in cortex, endodermis and pericycle cells under Zn deficient conditions. In N. caerulescens, the promoters were active in the same tissues, though the activity of the NcZNT1 promoter was higher and not limited to Zn deficient conditions. Common cis elements were identified in both promoters by 5’ deletion analysis. These correspond to the previously determined Zinc Deficiency Responsive Elements found in A. thaliana to interact with two redundantly acting transcription factors, bZIP19 and bZIP23, controlling the Zn deficiency response. In conclusion, these results suggest that NcZNT1 is an important factor in contributing to Zn and Cd hyperaccumulation in N. caerulescens. Differences in cis- and trans-regulators are likely to account for the differences in expression between A. thaliana and N. caerulescens. The high, constitutive NcZNT1 expression in the stele of N. caerulescens roots implicates its involvement in long distance root-to-shoot metal transport by maintaining a Zn/Cd influx into cells responsible for xylem loading. PMID:26930473

Iron plaque decreases cadmium accumulation in Oryza sativa L. and serves as a source of iron.

PubMed

Sebastian, A; Prasad, M N V

2016-11-01

Cadmium (Cd) contamination occurs in paddy soils; hence it is necessary to reduce Cd content of rice. Application and mode of action of ferrous sulphate in minimizing Cd in rice was monitored in the present study. Pot culture with Indian rice variety Swarna (MTU 7029) was maintained in Cd-spiked soil containing ferrous sulphates, which is expected to reduce Cd accumulation in rice. Responses in rhizosphere pH, root surface, metal accumulation in plant and molecular physiological processes were monitored. Iron plaque was induced on root surfaces after FeSO4 application and the amount of Fe in plaque reduced with increases in Cd in the soil. Rhizosphere pH decreased during plaque formation and became more acidic due to secretion of organic acids from the roots under Cd treatment. Moreover, iron chelate reductase activity increased with Cd treatment, but in the absence of Cd, activity of this enzyme increased in plaque-induced plants. Cd treatment caused expression of OsYSL18, whereas OsYSL15 was expressed only in roots without iron plaque. Fe content of plants increased during plaque formation, which protected plants from Cd-induced Fe deficiency and metal toxicity. This was corroborated with increased biomass, chlorophyll content and quantum efficiency of photo-synthesis among plaque-induced plants. We conclude that ferrous sulphate-induced iron plaque prevents Cd accumulation and Fe deficiency in rice. Iron released from plaque via organic acid mediated dissolution during Cd stress. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

Gibberellin regulates pollen viability and pollen tube growth in rice.

PubMed

Chhun, Tory; Aya, Koichiro; Asano, Kenji; Yamamoto, Eiji; Morinaka, Yoichi; Watanabe, Masao; Kitano, Hidemi; Ashikari, Motoyuki; Matsuoka, Makoto; Ueguchi-Tanaka, Miyako

2007-12-01

Gibberellins (GAs) play many biological roles in higher plants. We collected and performed genetic analysis on rice (Oryza sativa) GA-related mutants, including GA-deficient and GA-insensitive mutants. Genetic analysis of the mutants revealed that rice GA-deficient mutations are not transmitted as Mendelian traits to the next generation following self-pollination of F1 heterozygous plants, although GA-insensitive mutations are transmitted normally. To understand these differences in transmission, we examined the effect of GA on microsporogenesis and pollen tube elongation in rice using new GA-deficient and GA-insensitive mutants that produce semifertile flowers. Phenotypic analysis revealed that the GA-deficient mutant reduced pollen elongation1 is defective in pollen tube elongation, resulting in a low fertilization frequency, whereas the GA-insensitive semidominant mutant Slr1-d3 is mainly defective in viable pollen production. Quantitative RT-PCR revealed that GA biosynthesis genes tested whose mutations are transmitted to the next generation at a lower frequency are preferentially expressed after meiosis during pollen development, but expression is absent or very low before the meiosis stage, whereas GA signal-related genes are actively expressed before meiosis. Based on these observations, we predict that the transmission of GA-signaling genes occurs in a sporophytic manner, since the protein products and/or mRNA transcripts of these genes may be introduced into pollen-carrying mutant alleles, whereas GA synthesis genes are transmitted in a gametophytic manner, since these genes are preferentially expressed after meiosis.

Ultraviolet B-Sensitive Rice Cultivar Deficient in Cyclobutyl Pyrimidine Dimer Repair.

PubMed Central

Hidema, J.; Kumagai, T.; Sutherland, J. C.; Sutherland, B. M.

1997-01-01

Repair of cyclobutyl pyrimidine dimers (CPDs) in DNA is essential in most organisms to prevent biological damage by ultraviolet (UV) light. In higher plants tested thus far, UV-sensitive strains had higher initial damage levels or deficient repair of nondimer DNA lesions but normal CPD repair. This suggested that CPDs might not be important for biological lesions. The photosynthetic apparatus has also been proposed as a critical target. We have analyzed CPD induction and repair in the UV-sensitive rice (Oryza sativa L.) cultivar Norin 1 and its close relative UV-resistant Sasanishiki using alkaline agarose gel electrophoresis. Norin 1 is deficient in cyclobutyl pyrimidine dimer photoreactivation and excision; thus, UV sensitivity correlates with deficient dimer repair. PMID:12223592

Intercellular production of tamavidin 1, a biotin-binding protein from Tamogitake mushroom, confers resistance to the blast fungus Magnaporthe oryzae in transgenic rice.

PubMed

Takakura, Yoshimitsu; Oka, Naomi; Suzuki, Junko; Tsukamoto, Hiroshi; Ishida, Yuji

2012-05-01

The blast fungus Magnaporthe oryzae, one of the most devastating rice pathogens in the world, shows biotin-dependent growth. We have developed a strategy for creating disease resistance to M. oryzae whereby intercellular production of tamavidin 1, a biotin-binding protein from Pleurotus cornucopiae occurs in transgenic rice plants. The gene that encodes tamavidin 1, fused to the sequence for a secretion signal peptide derived from rice chitinase gene, was connected to the Cauliflower mosaic virus 35S promoter, and the resultant construct was introduced into rice. The tamavidin 1 was accumulated at levels of 0.1-0.2% of total soluble leaf proteins in the transgenic rice and it was localized in the intercellular space of rice leaves. The tamavidin 1 purified from the transgenic rice was active, it bound to biotin and inhibited in vitro growth of M. oryzae by causing biotin deficiency. The transgenic rice plants showed a significant resistance to M. oryzae. This study shows the possibility of a new strategy to engineer disease resistance in higher plants by taking advantage of a pathogen's auxotrophy.

Ethylene-dependent aerenchyma formation in adventitious roots is regulated differently in rice and maize.

PubMed

Yamauchi, Takaki; Tanaka, Akihiro; Mori, Hitoshi; Takamure, Itsuro; Kato, Kiyoaki; Nakazono, Mikio

2016-10-01

In roots of gramineous plants, lysigenous aerenchyma is created by the death and lysis of cortical cells. Rice (Oryza sativa) constitutively forms aerenchyma under aerobic conditions, and its formation is further induced under oxygen-deficient conditions. However, maize (Zea mays) develops aerenchyma only under oxygen-deficient conditions. Ethylene is involved in lysigenous aerenchyma formation. Here, we investigated how ethylene-dependent aerenchyma formation is differently regulated between rice and maize. For this purpose, in rice, we used the reduced culm number1 (rcn1) mutant, in which ethylene biosynthesis is suppressed. Ethylene is converted from 1-aminocyclopropane-1-carboxylic acid (ACC) by the action of ACC oxidase (ACO). We found that OsACO5 was highly expressed in the wild type, but not in rcn1, under aerobic conditions, suggesting that OsACO5 contributes to aerenchyma formation in aerated rice roots. By contrast, the ACO genes in maize roots were weakly expressed under aerobic conditions, and thus ACC treatment did not effectively induce ethylene production or aerenchyma formation, unlike in rice. Aerenchyma formation in rice roots after the initiation of oxygen-deficient conditions was faster and greater than that in maize. These results suggest that the difference in aerenchyma formation in rice and maize is due to their different mechanisms for regulating ethylene biosynthesis. © 2016 John Wiley & Sons Ltd.

The rice mitochondrial iron transporter is essential for plant growth

PubMed Central

Bashir, Khurram; Ishimaru, Yasuhiro; Shimo, Hugo; Nagasaka, Seiji; Fujimoto, Masaru; Takanashi, Hideki; Tsutsumi, Nobuhiro; An, Gynheung; Nakanishi, Hiromi; Nishizawa, Naoko K.

2011-01-01

In plants, iron (Fe) is essential for mitochondrial electron transport, heme, and Fe-Sulphur (Fe-S) cluster synthesis; however, plant mitochondrial Fe transporters have not been identified. Here we show, identify and characterize the rice mitochondrial Fe transporter (MIT). Based on a transfer DNA library screen, we identified a rice line showing symptoms of Fe deficiency while accumulating high shoot levels of Fe. Homozygous knockout of MIT in this line resulted in a lethal phenotype. MIT localized to the mitochondria and complemented the growth of Δmrs3Δmrs4 yeast defective in mitochondrial Fe transport. The growth of MIT-knockdown (mit-2) plants was also significantly impaired despite abundant Fe accumulation. Further, the decrease in the activity of the mitochondrial and cytosolic Fe-S enzyme, aconitase, indicated that Fe-S cluster synthesis is affected in mit-2 plants. These results indicate that MIT is a mitochondrial Fe transporter essential for rice growth and development. PMID:21610725

Role of blue green algae biofertilizer in ameliorating the nitrogen demand and fly-ash stress to the growth and yield of rice (Oryza sativa L.) plants.

PubMed

Tripathi, R D; Dwivedi, S; Shukla, M K; Mishra, S; Srivastava, S; Singh, R; Rai, U N; Gupta, D K

2008-02-01

Rice is a major food crop throughout the world; however, accumulation of toxic metals and metalloids in grains in contaminated environments is a matter of growing concern. Field experiments were conducted to analyze the growth performance, elemental composition (Fe, Si, Zn, Mn, Cu, Ni, Cd and As) and yield of the rice plants (Oryza sativa L. cv. Saryu-52) grown under different doses of fly-ash (FA; applied @ 10 and 100 tha(-1) denoted as FA(10) and FA(100), respectively) mixed with garden soil (GS) in combination with nitrogen fertilizer (NF; applied @ 90 and 120 kg ha(-1) denoted as NF(90) and NF(120), respectively) and blue green algae biofertilizer (BGA; applied @ 12.5 kg ha(-1) denoted as BGA(12.5)). Significant enhancement of growth was observed in the plants growing on amended soils as compared to GS and best response was obtained in amendment of FA(10)+NF(90)+BGA(12.5). Accumulation of Si, Fe, Zn and Mn was higher than Cu, Cd, Ni and As. Arsenic accumulation was detected only in FA(100) and its amendments. Inoculation of BGA(12.5) caused slight reduction in Cd, Ni and As content of plants as compared to NF(120) amendment. The high levels of stress inducible non-protein thiols (NP-SH) and cysteine in FA(100) were decreased by application of NF and BGA indicating stress amelioration. Study suggests integrated use of FA, BGA and NF for improved growth, yield and mineral composition of the rice plants besides reducing the high demand of nitrogen fertilizers.

Dark septate endophyte decreases stress on rice plants.

PubMed

Santos, Silvana Gomes Dos; Silva, Paula Renata Alves da; Garcia, Andres Calderin; Zilli, Jerri Édson; Berbara, Ricardo Luis Louro

Abiotic stress is one of the major limiting factors for plant development and productivity, which makes it important to identify microorganisms capable of increasing plant tolerance to stress. Dark septate endophytes can be symbionts of plants. In the present study, we evaluated the ability of dark septate endophytes isolates to reduce the effects of water stress in the rice varieties Nipponbare and Piauí. The experiments were performed under gnotobiotic conditions, and the water stress was induced with PEG. Four dark septate endophytes were isolated from the roots of wild rice (Oryza glumaepatula) collected from the Brazilian Amazon. Plant height as well as shoot and root fresh and dry matter were measured. Leaf protein concentrations and antioxidant enzyme activity were also estimated. The dark septate endophytes were grown in vitro in Petri dishes containing culture medium; they exhibited different levels of tolerance to salinity and water stress. The two rice varieties tested responded differently to inoculation with dark septate endophytes. Endophytes promoted rice plant growth both in the presence and in the absence of a water deficit. Decreased oxidative stress in plants in response to inoculation was observed in nearly all inoculated treatments, as indicated by the decrease in antioxidant enzyme activity. Dark septate endophytes fungi were shown to increase the tolerance of rice plants to stress caused by water deficiency. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

The iron-chelate transporter OsYSL9 plays a role in iron distribution in developing rice grains.

PubMed

Senoura, Takeshi; Sakashita, Emi; Kobayashi, Takanori; Takahashi, Michiko; Aung, May Sann; Masuda, Hiroshi; Nakanishi, Hiromi; Nishizawa, Naoko K

2017-11-01

Rice OsYSL9 is a novel transporter for Fe(II)-nicotianamine and Fe(III)-deoxymugineic acid that is responsible for internal iron transport, especially from endosperm to embryo in developing seeds. Metal chelators are essential for safe and efficient metal translocation in plants. Graminaceous plants utilize specific ferric iron chelators, mugineic acid family phytosiderophores, to take up sparingly soluble iron from the soil. Yellow Stripe 1-Like (YSL) family transporters are responsible for transport of metal-phytosiderophores and structurally similar metal-nicotianamine complexes. Among the rice YSL family members (OsYSL) whose functions have not yet been clarified, OsYSL9 belongs to an uncharacterized subgroup containing highly conserved homologs in graminaceous species. In the present report, we showed that OsYSL9 localizes mainly to the plasma membrane and transports both iron(II)-nicotianamine and iron(III)-deoxymugineic acid into the cell. Expression of OsYSL9 was induced in the roots but repressed in the nonjuvenile leaves in response to iron deficiency. In iron-deficient roots, OsYSL9 was induced in the vascular cylinder but not in epidermal cells. Although OsYSL9-knockdown plants did not show a growth defect under iron-sufficient conditions, these plants were more sensitive to iron deficiency in the nonjuvenile stage compared with non-transgenic plants. At the grain-filling stage, OsYSL9 expression was strongly and transiently induced in the scutellum of the embryo and in endosperm cells surrounding the embryo. The iron concentration was decreased in embryos of OsYSL9-knockdown plants but was increased in residual parts of brown seeds. These results suggested that OsYSL9 is involved in iron translocation within plant parts and particularly iron translocation from endosperm to embryo in developing seeds.

Copper and zinc uptake by rice and accumulation in soil amended with municipal solid waste compost

NASA Astrophysics Data System (ADS)

Bhattacharyya, P.; Chakraborty, A.; Chakrabarti, K.; Tripathy, S.; Powell, M. A.

2006-04-01

Effect of addition of municipal solid waste compost (MSWC) on two metals viz. copper (Cu) and zinc (Zn) contents of submerged rice paddies were studied. Experiments were conducted during the three consecutive wet seasons from 1997 to 1999 on rice grown under submergence, at the Experimental Farm of Calcutta University, India. A sequential extraction method was used to determine the metal (Cu and Zn) fractions in MSWC and cow dung manure (CDM). Both metals were significantly bound to the organic matter and Fe and Mn oxides in MSWC and CDM. Metal content in rice straw was higher than in rice grain. Metal bound with Fe and Mn oxides in MSWC and CDM best correlated with straw and grain metal followed by exchangeable and water soluble fractions. Carbonate, organic matter bound and residual fractions in MSWC and CDM did not significantly correlate with rice straw and grain metal. The MSWC would be a valuable resource for agriculture if it can be used safely, but long-term field experiments with MSWC are needed to assess by regular monitoring of the metal loads and accumulation in soil and plants.

Anaerobic conditions improve germination of a gibberellic acid deficient rice

NASA Technical Reports Server (NTRS)

Frantz, Jonathan M.; Bugbee, Bruce

2002-01-01

Dwarf plants are useful in research because multiple plants can be grown in a small area. Rice (Oryza sativa L.) is especially important since its relatively simple genome has recently been sequenced. We are characterizing a gibberellic acid (GA) mutant of rice (japonica cv 'Shiokari,' line N-71) that is extremely dwarf (20 cm tall). Unfortunately, this GA mutation is associated with poor germination (70%) under aerobic conditions. Neither exogenous GA nor a dormancy-breaking heat treatment improved germination. However, 95% germination was achieved by germinating the seeds anaerobically, either in a pure N2 environment or submerged in unstirred tap water. The anaerobic conditions appear to break a mild post-harvest dormancy in this rice cultivar. Copyright 2002 Crop Science Society of America.

Anaerobic conditions improve germination of a gibberellic acid deficient rice.

PubMed

Frantz, Jonathan M; Bugbee, Bruce

2002-01-01

Dwarf plants are useful in research because multiple plants can be grown in a small area. Rice (Oryza sativa L.) is especially important since its relatively simple genome has recently been sequenced. We are characterizing a gibberellic acid (GA) mutant of rice (japonica cv 'Shiokari,' line N-71) that is extremely dwarf (20 cm tall). Unfortunately, this GA mutation is associated with poor germination (70%) under aerobic conditions. Neither exogenous GA nor a dormancy-breaking heat treatment improved germination. However, 95% germination was achieved by germinating the seeds anaerobically, either in a pure N2 environment or submerged in unstirred tap water. The anaerobic conditions appear to break a mild post-harvest dormancy in this rice cultivar. Copyright 2002 Crop Science Society of America.

A salivary sheath protein essential for the interaction of the brown planthopper with rice plants.

PubMed

Huang, Hai-Jian; Liu, Cheng-Wen; Cai, Ye-Fang; Zhang, Min-Zhu; Bao, Yan-Yuan; Zhang, Chuan-Xi

2015-11-01

Salivary secretions, including gel saliva and watery saliva, play crucial roles in the interaction between the insect and plant during feeding. In this study, we identified a salivary gland-specific gene encoding a salivary sheath protein (NlShp) in Nilaparvata lugens. NlShp has two alternative splicing variants; both are expressed at high levels during the nymph and adult stages. Immunohistochemical staining showed that the NlShp were synthesized in the principal gland cells of the salivary gland. LC-MS/MS and western blot analysis confirmed that NlShp was one of the components of the salivary sheath. Simultaneously knocking down the two NlShp variants by RNA interference inhibited both salivary flange and salivary sheath formation and resulted in a lethal phenotype within four days for the brown planthopper (BPH) feeding on rice plants, indicating that the salivary sheath and salivary flanges were essential for plant-associated feeding. Despite the salivary sheath deficiency, no obvious phenotype was observed in the NlShp-knockdown BPHs fed on artificial diet. The electrical penetration graph (EPG) results showed that salivary sheath-deficient BPHs exhibited a prolonged nonpenetration period, scarce sap period, and increased stylet movement on rice plants and eventually starved to death. Our results provided evidence that the interaction between the salivary sheath and host plant might be a critical step in successful BPH feeding. According to present research, we propose a salivary sheath required feeding model for piercing-sucking insects and provide a potential target for rice planthopper management. Copyright © 2015 Elsevier Ltd. All rights reserved.

A rapid and efficient method to study the function of crop plant transporters in Arabidopsis

USDA-ARS?s Scientific Manuscript database

Iron (Fe) is an essential micronutrient for humans. Fe deficiency disease is wide-spread and has lead to extensive studies on the mechanisms of Fe uptake and storage, especially in staple food crops such as rice. However, studies of functionally related genes in rice and other crops are often time a...

New approach to increasing rice lodging resistance and biomass yield through the use of high gibberellin producing varieties.

PubMed

Okuno, Ayako; Hirano, Ko; Asano, Kenji; Takase, Wakana; Masuda, Reiko; Morinaka, Yoichi; Ueguchi-Tanaka, Miyako; Kitano, Hidemi; Matsuoka, Makoto

2014-01-01

Traditional breeding for high-yielding rice has been dependent on the widespread use of fertilizers and the cultivation of gibberellin (GA)-deficient semi-dwarf varieties. The use of semi-dwarf plants facilitates high grain yield since these varieties possess high levels of lodging resistance, and thus could support the high grain weight. Although this approach has been successful in increasing grain yield, it is desirable to further improve grain production and also to breed for high biomass. In this study, we re-examined the effect of GA on rice lodging resistance and biomass yield using several GA-deficient mutants (e.g. having defects in the biosynthesis or perception of GA), and high-GA producing line or mutant. GA-deficient mutants displayed improved bending-type lodging resistance due to their short stature; however they showed reduced breaking-type lodging resistance and reduced total biomass. In plants producing high amounts of GA, the bending-type lodging resistance was inferior to the original cultivars. The breaking-type lodging resistance was improved due to increased lignin accumulation and/or larger culm diameters. Further, these lines had an increase in total biomass weight. These results show that the use of rice cultivars producing high levels of GA would be a novel approach to create higher lodging resistance and biomass.

Inducible antisense suppression of glycolate oxidase reveals its strong regulation over photosynthesis in rice.

PubMed

Xu, Huawei; Zhang, Jianjun; Zeng, Jiwu; Jiang, Linrong; Liu, Ee; Peng, Changlian; He, Zhenghui; Peng, Xinxiang

2009-01-01

Photorespiration is one of the most intensively studied topics in plant biology. While a number of mutants deficient in photorespiratory enzymes have been identified and characterized for their physiological functions, efforts on glycolate oxidase (GLO; EC 1.1.3.15) have not been so successful. This is a report about the generation of transgenic rice (Oryza sativa L.) plants carrying a GLO antisense gene driven by an estradiol-inducible promoter, which allowed for controllable suppressions of GLO and its detailed functional analyses. The GLO-suppressed plants showed typical photorespiration-deficient phenotypes. More intriguingly, it was found that a positive and linear correlation existed between GLO activities and the net photosynthetic rates (P(N)), and photoinhibition subsequently occurred once P(N) reduction surpassed 60%, indicating GLO can exert a strong regulation over photosynthesis. Various expression analyses identified that Rubisco activase was transcriptionally suppressed in the GLO-suppressed plants, consistent with the decreased Rubisco activation states. While the substrate glycolate accumulated substantially, few changes were observed for the product glyoxylate, and for some other downstream metabolites or genes as well in the transgenic plants. Further analyses revealed that isocitrate lyase and malate synthase, two key enzymes in the glyoxylate cycle, were highly up-regulated under GLO deficiency. Taken together, the results suggest that GLO is a typical photorespiratory enzyme and that it can exert a strong regulation over photosynthesis, possibly through a feed-back inhibition on Rubisco activase, and that the glyoxylate cycle may be partially activated to compensate for the photorespiratory glyoxylate when GLO is suppressed in rice.

Growth performance and biochemical responses of three rice (Oryza sativa L.) cultivars grown in fly-ash amended soil.

PubMed

Dwivedi, S; Tripathi, R D; Srivastava, S; Mishra, S; Shukla, M K; Tiwari, K K; Singh, R; Rai, U N

2007-02-01

The disposal of fly-ash (FA) from coal-fired power stations causes significant economic and environmental problems. Use of such contaminated sites for crop production and use of contaminated water for irrigation not only decreases crop productivity but also poses health hazards to humans due to accumulation of toxic metals in edible grains. In the present investigation, three rice cultivars viz., Saryu-52, Sabha-5204, and Pant-4 were grown in garden soil (GS, control) and various amendments (10%, 25%, 50%, 75% and 100%) of FA for a period of 90 days and effect on growth and productivity of plant was evaluated vis-a-vis metal accumulation in the plants. The toxicity of FA at higher concentration (50%) was reflected by the reduction in photosynthetic pigments, protein and growth parameters viz., plant height, root biomass, number of tillers, grain and straw weight. However, at lower concentrations (10-25%), FA enhanced growth of the plants as evident by the increase of studied growth parameters. The cysteine and non-protein thiol (NP-SH) content showed increase in their levels up to 100% FA as compared to control, however, maximum content was found at 25% FA in Saryu-52 and Pant-4 and at 50% FA in Sabha-5204. Accumulation of Fe, Si, Cu, Zn, Mn, Ni, Cd and As was investigated in roots, leaves and seeds of the plants. Fe accumulation was maximum in all the parts of plant followed by Si and both showed more translocation to leaves while Mn, Zn, Cu, Ni and Cd showed lower accumulation and most of the metal was confined to roots in all the three cultivars. As was accumulated only in leaves and was not found to be in detectable levels in roots and seeds. The metal accumulation order in three rice cultivars was Fe > Si > Mn > Zn > Ni > Cu > Cd > As in all the plant parts. The results showed that rice varieties Saryu-52 and Sabha-5204 were more tolerant and could show improved growth and yield in lower FA application doses as compared to Pant-4. Thus, Sabha-5204 and Saryu-52 are found suitable for cultivation in FA amended agricultural soils for better crop yields.

Sites of action of elevated CO2 on leaf development in rice: discrimination between the effects of elevated CO2 and nitrogen deficiency.

PubMed

Tsutsumi, Koichi; Konno, Masae; Miyazawa, Shin-Ichi; Miyao, Mitsue

2014-02-01

Elevated CO2 concentrations (eCO2) trigger various plant responses. Despite intensive studies of these responses, the underlying mechanisms remain obscure. In this work, we investigated when and how leaf physiology and anatomy are affected by eCO2 in rice plants. We analyzed the most recently fully expanded leaves that developed successively after transfer of the plant to eCO2. To discriminate between the effects of eCO2 and those of nitrogen deficiency, we used three different levels of N application. We found that a decline in the leaf soluble protein content (on a leaf area basis) at eCO2 was only observed under N deficiency. The length and width of the leaf blade were reduced by both eCO2 and N deficiency, whereas the blade thickness was increased by eCO2 but was not affected by N deficiency. The change in length by eCO2 became detectable in the secondly fully expanded leaf, and those in width and thickness in the thirdly fully expanded leaf, which were at the leaf developmental stages P4 and P3, respectively, at the onset of the eCO2 treatment. The decreased blade length at eCO2 was associated with a decrease in the epidermal cell number on the adaxial side and a reduction in cell length on the abaxial side. The decreased width resulted from decreased numbers of small vascular bundles and epidermal cell files. The increased thickness was ascribed mainly to enhanced development of bundle sheath extensions at the ridges of vascular bundles. These observations enable us to identify the sites of action of eCO2 on rice leaf development.

Iron Bioavailability from Ferric Pyrophosphate in Extruded Rice Cofortified with Zinc Sulfate Is Greater than When Cofortified with Zinc Oxide in a Human Stable Isotope Study.

PubMed

Hackl, Laura; Zimmermann, Michael B; Zeder, Christophe; Parker, Megan; Johns, Paul W; Hurrell, Richard F; Moretti, Diego

2017-03-01

Background: Extruded rice grains are often cofortified with iron and zinc. However, it is uncertain if the addition of zinc to iron-fortified rice affects iron absorption and whether this is zinc-compound specific. Objective: We investigated whether zinc, added as zinc oxide (ZnO) or zinc sulfate (ZnSO 4 ), affects human iron absorption from extruded rice fortified with ferric pyrophosphate (FePP). Methods: In 19 iron-depleted Swiss women (plasma ferritin ≤16.5 μ/L) aged between 20 and 39 y with a normal body mass index (in kg/m 2 ; 18.7-24.8), we compared iron absorption from 4 meals containing fortified extruded rice with 4 mg Fe and 3 mg Zn. Three of the meals contained extruded rice labeled with FePP ( 57 FePP): 1 ) 1 meal without added zinc ( 57 FePP-Zn), 2 ) 1 cofortified with ZnO ( 57 FePP+ZnO), and 3 ) 1 cofortified with ZnSO 4 ( 57 FePP+ZnSO 4 ). The fourth meal contained extruded rice without iron or zinc, extrinsically labeled with ferrous sulfate ( 58 FeSO 4 ) added as a solution after cooking. All 4 meals contained citric acid. Iron bioavailability was measured by isotopic iron ratios in red blood cells. We also measured relative in vitro iron solubility from 57 FePP-Zn, 57 FePP+ZnO, and 57 FePP+ZnSO 4 expressed as a fraction of FeSO 4 solubility. Results: Geometric mean fractional iron absorption (95% CI) from 57 FePP+ZnSO 4 was 4.5% (3.4%, 5.8%) and differed from 57 FePP+ZnO (2.7%; 1.8%, 4.1%) ( P < 0.03); both did not differ from 57 FePP-Zn: 4.0% (2.8%, 5.6%). Relative iron bioavailabilities compared with 58 FeSO 4 were 62%, 57%, and 38% from 57 FePP+ZnSO 4 , 57 FePP-Zn, and 57 FePP+ZnO, respectively. In vitro solubility from 57 FePP+ZnSO 4 differed from that of 57 FePP-Zn (14.3%; P < 0.02) but not from that of 57 FePP+ZnO (10.2% compared with 13.1%; P = 0.08). Conclusions: In iron-depleted women, iron absorption from FePP-fortified extruded rice cofortified with ZnSO 4 was 1.6-fold (95% CI: 1.4-, 1.9-fold) that of rice cofortified with ZnO. These findings suggest that ZnSO 4 may be the preferable zinc cofortificant for optimal iron bioavailability of iron-fortified extruded rice. This trial was registered at clinicaltrials.gov as NCT02255942. © 2017 American Society for Nutrition.

The knockdown of OsVIT2 and MIT affects iron localization in rice seed.

PubMed

Bashir, Khurram; Takahashi, Ryuichi; Akhtar, Shamim; Ishimaru, Yasuhiro; Nakanishi, Hiromi; Nishizawa, Naoko K

2013-11-20

The mechanism of iron (Fe) uptake in plants has been extensively characterized, but little is known about how Fe transport to different subcellular compartments affects Fe localization in rice seed. Here, we discuss the characterization of a rice vacuolar Fe transporter 2 (OsVIT2) T-DNA insertion line (osvit2) and report that the knockdown of OsVIT2 and mitochondrial Fe transporter (MIT) expression affects seed Fe localization. osvit2 plants accumulated less Fe in their shoots when grown under normal or excess Fe conditions, while the accumulation of Fe was comparable to that in wild-type (WT) plants under Fe-deficient conditions. The accumulation of zinc, copper, and manganese also changed significantly in the shoots of osvit2 plants. The growth of osvit2 plants was also slow compared to that of WT plants. The concentration of Fe increased in osvit2 polished seeds. Previously, we reported that the expression of OsVIT2 was higher in MIT knockdown (mit-2) plants, and in this study, the accumulation of Fe in mit-2 seeds decreased significantly. These results suggest that vacuolar Fe trafficking is important for plant Fe homeostasis and distribution, especially in plants grown in the presence of excess Fe. Moreover, changes in the expression of OsVIT2 and MIT affect the concentration and localization of metals in brown rice as well as in polished rice seeds.

The role of ZIP transporters and group F bZIP transcription factors in the Zn-deficiency response of wheat (Triticum aestivum).

PubMed

Evens, Nicholas P; Buchner, Peter; Williams, Lorraine E; Hawkesford, Malcolm J

2017-10-01

Understanding the molecular basis of zinc (Zn) uptake and transport in staple cereal crops is critical for improving both Zn content and tolerance to low-Zn soils. This study demonstrates the importance of group F bZIP transcription factors and ZIP transporters in responses to Zn deficiency in wheat (Triticum aestivum). Seven group F TabZIP genes and 14 ZIPs with homeologs were identified in hexaploid wheat. Promoter analysis revealed the presence of Zn-deficiency-response elements (ZDREs) in a number of the ZIPs. Functional complementation of the zrt1/zrt2 yeast mutant by TaZIP3, -6, -7, -9 and -13 supported an ability to transport Zn. Group F TabZIPs contain the group-defining cysteine-histidine-rich motifs, which are the predicted binding site of Zn 2+ in the Zn-deficiency response. Conservation of these motifs varied between the TabZIPs suggesting that individual TabZIPs may have specific roles in the wheat Zn-homeostatic network. Increased expression in response to low Zn levels was observed for several of the wheat ZIPs and bZIPs; this varied temporally and spatially suggesting specific functions in the response mechanism. The ability of the group F TabZIPs to bind to specific ZDREs in the promoters of TaZIPs indicates a conserved mechanism in monocots and dicots in responding to Zn deficiency. In support of this, TabZIPF1-7DL and TabZIPF4-7AL afforded a strong level of rescue to the Arabidopsis hypersensitive bzip19 bzip23 double mutant under Zn deficiency. These results provide a greater understanding of Zn-homeostatic mechanisms in wheat, demonstrating an expanded repertoire of group F bZIP transcription factors, adding to the complexity of Zn homeostasis. © 2017 The Authors The Plant Journal published by John Wiley & Sons Ltd and Society for Experimental Biology.

Plants for human health: Stable isotope approaches to assess the vitamin A value of biofortified Golden Rice and high beta-carotene maize

USDA-ARS?s Scientific Manuscript database

Vitamin A deficiency is a major public health problem, especially in populations of the developing world where staple foods, such as rice, wheat, and maize, make up a significant portion of daily caloric intake. Seeds of these crops contain little to no provitamin A carotenoids (e.g., beta-carotene...

Sewage sludge biochar influence upon rice (Oryza sativa L) yield, metal bioaccumulation and greenhouse gas emissions from acidic paddy soil.

PubMed

Khan, Sardar; Chao, Cai; Waqas, Muhammad; Arp, Hans Peter H; Zhu, Yong-Guan

2013-08-06

Biochar addition to soil has been proposed to improve plant growth by increasing soil fertility, minimizing bioaccumulation of toxic metal(liod)s and mitigating climate change. Sewage sludge (SS) is an attractive, though potentially problematic, feedstock of biochar. It is attractive because of its large abundance; however, it contains elevated concentrations of metal(loid)s and other contaminants. The pyrolysis of SS to biochar (SSBC) may be a way to reduce the availability of these contaminants to the soil and plants. Using rice plant pot experiments, we investigated the influence of SSBC upon biomass yield, bioaccumulation of nutrients, and metal(loid)s, and green housegas (GHG) emissions. SSBC amendments increased soil pH, total nitrogen, soil organic carbon and available nutrients and decreased bioavailable As, Cr, Co, Ni, and Pb (but not Cd, Cu, and Zn). Regarding rice plant properties, SSBC amendments significantly (P ≤ 0.01) increased shoot biomass (71.3-92.2%), grain yield (148.8-175.1%), and the bioaccumulation of phosphorus and sodium, though decreased the bioaccumulation of nitrogen (except in grain) and potassium. Amendments of SSBC significantly (P ≤ 0.05) reduced the bioaccumulation of As, Cr, Co, Cu, Ni, and Pb, but increased that of Cd and Zn, though not above limits set by Chinese regulations. Finally regarding GHG emissions, SSBC significantly (P < 0.01) reduced N2O emissions and stimulated the uptake/oxidation of CH4 enough to make both the cultivated and uncultivated paddy soil a CH4 sink. SSBC can be beneficial in rice paddy soil but the actual associated benefits will depend on site-specific conditions and source of SS; long-term effects remain a further unknown.

Phosphate stresses affect ionome and metabolome in tea plants.

PubMed

Ding, Zhaotang; Jia, Sisi; Wang, Yu; Xiao, Jun; Zhang, Yinfei

2017-11-01

In order to study the response of tea plants to P stress, we conducted the ionomic and metabolomic analysis by ICP-OES, GC-MS and LC-MS. The results demonstrated that P was antagonistic with S, and was cooperative with Cu, Zn, Mn and Fe under P-deficiency. However, P was antagonistic with Mn, Fe and S, and was cooperative with Cu and Zn under P-excess. Moreover, P-deficiency or excess reduced the syntheses of flavonoids and phosphorylated metabolites. P-deficiency decreased the amount of glutamate and increased the content of glutamine, while P-excess decreased the content of glutamine. Besides, P-deficiency increased three organic acids and decreased three organic acids. P-excess increased the contents of malic acid, oxalic acid, ribonic acid and etc. involved in primary metabolism, but decreased the contents of p-coumaric acid, indoleacrylic acid, related to secondary metabolism. Furthermore, the contents of Mn and Zn were found to be positively related to the amounts of myricetin and quercetin, and the content of Mn to be positively related to the amount of arabinose. The results implied that the P stresses severely disturbed the metabolism of minerals and metabolites in tea plants, which influenced the yield and quality of tea. Copyright © 2017. Published by Elsevier Masson SAS.

Engineering the lodging resistance mechanism of post-Green Revolution rice to meet future demands.

PubMed

Hirano, Ko; Ordonio, Reynante Lacsamana; Matsuoka, Makoto

2017-01-01

Traditional breeding for high-yielding rice has been dependent on the widespread cultivation of gibberellin (GA)-deficient semi-dwarf varieties. Dwarfism lowers the "center of gravity" of the plant body, which increases resistance against lodging and enables plants to support high grain yield. Although this approach was successful in latter half of the 20th century in rice and wheat breeding, this may no longer be enough to sustain rice with even higher yields. This is because relying solely on the semi-dwarf trait is subject to certain limitations, making it necessary to use other important traits to reinforce it. In this review, we present an alternative approach to increase lodging resistance by improving the quality of the culm by identifying genes related to culm quality and introducing these genes into high-yielding rice cultivars through molecular breeding technique.

Native plant communities in an abandoned Pb-Zn mining area of northern Spain: implications for phytoremediation and germplasm preservation.

PubMed

Barrutia, O; Artetxe, U; Hernández, A; Olano, J M; García-Plazaola, J I; Garbisu, C; Becerril, J M

2011-03-01

Plants growing on metalliferous soils from abandoned mines are unique because of their ability to cope with high metal levels in soil. In this study, we characterized plants and soils from an abandoned Pb-Zn mine in the Basque Country (northern Spain). Soil in this area proved to be deficient in major macronutrients and to contain toxic levels of Cd, Pb, and Zn. Spontaneously growing native plants (belonging to 31 species, 28 genera, and 15 families) were botanically identified. Plant shoots and rhizosphere soil were sampled at several sites in the mine, and analyzed for Pb, Zn and Cd concentration. Zinc showed the highest concentrations in shoots, followed by Pb and Cd. Highest Zn concentrations in shoots were found in the Zn-Cd hyperaccumulator Thlaspi caerulescens (mean = 18,254 mg Zn kg(-1) DW). Different metal tolerance and accumulation patterns were observed among the studied plant species, thus offering a wide germplasm assortment for the suitable selection of phytoremediation technologies. This study highlights the importance of preserving metalliferous environments as they shelter a unique and highly valuable metallicolous biodiversity.

OsNIP3;1, a rice boric acid channel, regulates boron distribution and is essential for growth under boron-deficient conditions.

PubMed

Hanaoka, Hideki; Uraguchi, Shimpei; Takano, Junpei; Tanaka, Mayuki; Fujiwara, Toru

2014-06-01

Boron is an essential micronutrient for higher plants. Boron deficiency is an important agricultural issue because it results in loss of yield quality and/or quantity in cereals and other crops. To understand boron transport mechanisms in cereals, we characterized OsNIP3;1, a member of the major intrinsic protein family in rice (Oryza sativa L.), because OsNIP3;1 is the most similar rice gene to the Arabidopsis thaliana boric acid channel genes AtNIP5;1 and AtNIP6;1. Yeast cells expressing OsNIP3;1 imported more boric acid than control cells. GFP-tagged OsNIP3;1 expressed in tobacco BY2 cells was localized to the plasma membrane. The accumulation of OsNIP3;1 transcript increased fivefold in roots within 6 h of the onset of boron starvation, but not in shoots. Promoter-GUS analysis suggested that OsNIP3;1 is expressed mainly in exodermal cells and steles in roots, as well as in cells around the vascular bundles in leaf sheaths and pericycle cells around the xylem in leaf blades. The growth of OsNIP3;1 RNAi plants was impaired under boron limitation. These results indicate that OsNIP3;1 functions as a boric acid channel, and is required for acclimation to boron limitation. Boron distribution among shoot tissues was altered in OsNIP3;1 knockdown plants, especially under boron-deficient conditions. This result demonstrates that OsNIP3;1 regulates boron distribution among shoot tissues, and that the correct boron distribution is crucial for plant growth. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

OsIRO2 is responsible for iron utilization in rice and improves growth and yield in calcareous soil.

PubMed

Ogo, Yuko; Itai, Reiko N; Kobayashi, Takanori; Aung, May Sann; Nakanishi, Hiromi; Nishizawa, Naoko K

2011-04-01

Iron (Fe) deficiency, a worldwide agricultural problem on calcareous soil with low Fe availability, is also a major human nutritional deficit. Plants induce Fe acquisition systems under conditions of low Fe availability. Previously, we reported that an Fe-deficiency-inducible basic helix-loop-helix (bHLH) transcription factor, OsIRO2, is responsible for regulation of the genes involved in Fe homeostasis in rice. Using promoter-GUS transformants, we showed that OsIRO2 is expressed throughout a plant's lifetime in a spatially and temporally similar manner to the genes OsNAS1, OsNAS2 and TOM1, which is involved in Fe absorption and translocation. During germination, OsIRO2 expression was detected in embryos. OsIRO2 expression in vegetative tissues was restricted almost exclusively to vascular bundles of roots and leaves, and to the root exodermis under Fe-sufficient conditions, and expanded to all tissues of roots and leaves in response to Fe deficiency. OsIRO2 expression was also detected in flowers and developing seeds. Plants overexpressing OsIRO2 grew better, and OsIRO2-repressed plants showed poor growth compared to non-transformant rice after germination. OsIRO2 overexpression also resulted in improved tolerance to low Fe availability in calcareous soil. In addition to increased Fe content in shoots, the overexpression plants accumulated higher amounts of Fe in seeds than non-transformants when grown on calcareous soil. These results suggest that OsIRO2 is synchronously expressed with genes involved in Fe homeostasis, and performs a crucial function in regulation not only of Fe uptake from soil but also Fe transport during germination and Fe translocation to grain during seed maturation.

Dissection of brassinosteroid-regulated proteins in rice embryos during germination by quantitative proteomics

PubMed Central

Li, Qian-Feng; Xiong, Min; Xu, Peng; Huang, Li-Chun; Zhang, Chang-Quan; Liu, Qiao-Quan

2016-01-01

Brassinosteroids (BRs), essential plant-specific steroidal hormones, function in a wide spectrum of plant growth and development events, including seed germination. Rice is not only a monocotyledonous model plant but also one of the most important staple food crops of human beings. Rice seed germination is a decisive event for the next-generation of plant growth and successful seed germination is critical for rice yield. However, little is known about the molecular mechanisms on how BR modulates seed germination in rice. In the present study, we used isobaric tags for relative and absolute quantification (iTRAQ) based proteomic approach to study BR-regulated proteome during the early stage of seed germination. The results showed that more than 800 BR-responsive proteins were identified, including 88 reliable target proteins responsive to stimuli of both BR-deficiency and BR-insensitivity. Moreover, 90% of the 88 target proteins shared a similar expression change pattern. Gene ontology and string analysis indicated that ribosomal structural proteins, as well as proteins involved in protein biosynthesis and carbohydrate metabolisms were highly clustered. These findings not only enrich BR-regulated protein database in rice seeds, but also allow us to gain novel insights into the molecular mechanism of BR regulated seed germination. PMID:27703189

Identification of a rice metal tolerance protein OsMTP11 as a manganese transporter

PubMed Central

Zhang, Mei; Liu, Baoxiu

2017-01-01

Metal tolerance proteins (MTPs) are a gene family of cation efflux transporters that occur widely in plants and might serve an essential role in metal homeostasis and tolerance. Our research describes the identification, characterization, and localization of OsMTP11, a member of the MTP family from rice. OsMTP11 was expressed constitutively and universally in different tissues in rice plant. Heterologous expression in yeast showed that OsMTP11 complemented the hypersensitivity of mutant strains to Mn, and also complemented yeast mutants to other metals, including Co and Ni. Real time RT-PCR analysis demonstrated OsMTP11 expression was substantially enhanced following 4 h under Cd, Zn, Ni, and Mn treatments, suggesting possible roles of OsMTP11 involvement in heavy metal stress responses. Promoter analysis by transgenic assays with GUS as a reporter gene and mRNA in situ hybridization experiments showed that OsMTP11 was expressed specifically in conducting tissues in rice. DNA methylation assays of genomic DNA in rice treated with Cd, Zn, Ni, and Mn revealed that decreased DNA methylation levels were present in the OsMTP11 promoter region, which was consistent with OsMTP11 induced-expression patterns resulting from heavy metal stress. This result suggested that DNA methylation is one of major factors regulating expression of OsMTP11 through epigenetic mechanisms. OsMTP11 fused to green fluorescent protein (GFP) localized to the entire onion epidermal cell cytoplasm, while vacuolar membrane exhibited increased GFP signals, consistent with an OsMTP11 function in cation sequestration. Our results indicated that OsMTP11 might play vital roles in Mn and other heavy metal transportation in rice. PMID:28394944

Magnaporthe oryzae Glycine-Rich Secretion Protein, Rbf1 Critically Participates in Pathogenicity through the Focal Formation of the Biotrophic Interfacial Complex

PubMed Central

Ishii-Minami, Naoko; Kawahara, Yoshihiro; Yoshida, Yuri; Okada, Kazunori; Ando, Sugihiro; Matsumura, Hideo; Terauchi, Ryohei; Minami, Eiichi; Nishizawa, Yoko

2016-01-01

Magnaporthe oryzae, the fungus causing rice blast disease, should contend with host innate immunity to develop invasive hyphae (IH) within living host cells. However, molecular strategies to establish the biotrophic interactions are largely unknown. Here, we report the biological function of a M. oryzae-specific gene, R equired-for-Focal- B IC- F ormation 1 (RBF1). RBF1 expression was induced in appressoria and IH only when the fungus was inoculated to living plant tissues. Long-term successive imaging of live cell fluorescence revealed that the expression of RBF1 was upregulated each time the fungus crossed a host cell wall. Like other symplastic effector proteins of the rice blast fungus, Rbf1 accumulated in the biotrophic interfacial complex (BIC) and was translocated into the rice cytoplasm. RBF1-knockout mutants (Δrbf1) were severely deficient in their virulence to rice leaves, but were capable of proliferating in abscisic acid-treated or salicylic acid-deficient rice plants. In rice leaves, Δrbf1 inoculation caused necrosis and induced defense-related gene expression, which led to a higher level of diterpenoid phytoalexin accumulation than the wild-type fungus did. Δrbf1 showed unusual differentiation of IH and dispersal of the normally BIC-focused effectors around the short primary hypha and the first bulbous cell. In the Δrbf1-invaded cells, symplastic effectors were still translocated into rice cells but with a lower efficiency. These data indicate that RBF1 is a virulence gene essential for the focal BIC formation, which is critical for the rice blast fungus to suppress host immune responses. PMID:27711180

Calcium biofortification of crops

USDA-ARS?s Scientific Manuscript database

More than half of the world's population is deficient in calcium (Ca), iron (Fe), iodine (I), magnesium (Mg), selenium (Se), or zinc (Zn). The consumption of plants, directly or via livestock, containing inadequate concentrations of particular minerals causes these deficiencies. Agronomic and geneti...

Efficient acquisition of iron confers greater tolerance to saline-alkaline stress in rice (Oryza sativa L.).

PubMed

Li, Qian; Yang, An; Zhang, Wen-Hao

2016-12-01

To elucidate the mechanisms underlying tolerance to saline-alkaline stress in two rice genotypes, Dongdao-4 and Jigeng-88, we exposed them to medium supplemented with 10 mM Na 2 CO 3 and 40 mM NaCl (pH 8.5). Dongdao-4 plants displayed higher biomass, chlorophyll content, and photosynthetic rates, and a larger root system than Jigeng-88 under saline-alkaline conditions. Dongdao-4 had a higher shoot Na + /K + ratio than Jigeng-88 under both control and saline-alkaline conditions. Dongdao-4 exhibited stronger rhizospheric acidification than Jigeng-88 under saline-alkaline conditions, resulting from greater up-regulation of H + -ATPases at the transcriptional level. Moreover, Fe concentrations in shoots and roots of Dongdao-4 were higher than those in Jigeng-88, and a higher rate of phytosiderophore exudation was detected in Dongdao-4 versus Jigeng-88 under saline-alkaline conditions. The Fe-deficiency-responsive genes OsIRO2, OsIRT1, OsNAS1, OsNAS2, OsYSL2, and OsYSL15 were more strongly up-regulated in Dongdao-4 than Jigeng-88 plants in saline-alkaline medium, implying greater tolerance of Dongdao-4 plants to Fe deficiency. To test this hypothesis, we compared the effects of Fe deficiency on the two genotypes, and found that Dongdao-4 was more tolerant to Fe deficiency. Exposure to Fe-deficient medium led to greater rhizospheric acidification and phytosiderophore exudation in Dongdao-4 than Jigeng-88 plants. Expression levels of OsIRO2, OsIRT1, OsNAS1, OsNAS2, OsYSL2, and OsYSL15 were higher in Dongdao-4 than Jigeng-88 plants under Fe-deficient conditions. These results demonstrate that a highly efficient Fe acquisition system together with a large root system may underpin the greater tolerance of Dongdao-4 plants to saline-alkaline stress. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Efficient acquisition of iron confers greater tolerance to saline-alkaline stress in rice (Oryza sativa L.)

PubMed Central

Li, Qian; Yang, An; Zhang, Wen-Hao

2016-01-01

To elucidate the mechanisms underlying tolerance to saline-alkaline stress in two rice genotypes, Dongdao-4 and Jigeng-88, we exposed them to medium supplemented with 10 mM Na2CO3 and 40 mM NaCl (pH 8.5). Dongdao-4 plants displayed higher biomass, chlorophyll content, and photosynthetic rates, and a larger root system than Jigeng-88 under saline-alkaline conditions. Dongdao-4 had a higher shoot Na+/K+ ratio than Jigeng-88 under both control and saline-alkaline conditions. Dongdao-4 exhibited stronger rhizospheric acidification than Jigeng-88 under saline-alkaline conditions, resulting from greater up-regulation of H+-ATPases at the transcriptional level. Moreover, Fe concentrations in shoots and roots of Dongdao-4 were higher than those in Jigeng-88, and a higher rate of phytosiderophore exudation was detected in Dongdao-4 versus Jigeng-88 under saline-alkaline conditions. The Fe-deficiency-responsive genes OsIRO2, OsIRT1, OsNAS1, OsNAS2, OsYSL2, and OsYSL15 were more strongly up-regulated in Dongdao-4 than Jigeng-88 plants in saline-alkaline medium, implying greater tolerance of Dongdao-4 plants to Fe deficiency. To test this hypothesis, we compared the effects of Fe deficiency on the two genotypes, and found that Dongdao-4 was more tolerant to Fe deficiency. Exposure to Fe-deficient medium led to greater rhizospheric acidification and phytosiderophore exudation in Dongdao-4 than Jigeng-88 plants. Expression levels of OsIRO2, OsIRT1, OsNAS1, OsNAS2, OsYSL2, and OsYSL15 were higher in Dongdao-4 than Jigeng-88 plants under Fe-deficient conditions. These results demonstrate that a highly efficient Fe acquisition system together with a large root system may underpin the greater tolerance of Dongdao-4 plants to saline-alkaline stress. PMID:27811002

Rosette iron deficiency transcript and microRNA profiling reveals links between copper and iron homeostasis in Arabidopsis thaliana

PubMed Central

Waters, Brian M.; Stein, Ricardo J.

2012-01-01

Iron (Fe) is an essential plant micronutrient, and its deficiency limits plant growth and development on alkaline soils. Under Fe deficiency, plant responses include up-regulation of genes involved in Fe uptake from the soil. However, little is known about shoot responses to Fe deficiency. Using microarrays to probe gene expression in Kas-1 and Tsu-1 ecotypes of Arabidopsis thaliana, and comparison with existing Col-0 data, revealed conserved rosette gene expression responses to Fe deficiency. Fe-regulated genes included known metal homeostasis-related genes, and a number of genes of unknown function. Several genes responded to Fe deficiency in both roots and rosettes. Fe deficiency led to up-regulation of Cu,Zn superoxide dismutase (SOD) genes CSD1 and CSD2, and down-regulation of FeSOD genes FSD1 and FSD2. Eight microRNAs were found to respond to Fe deficiency. Three of these (miR397a, miR398a, and miR398b/c) are known to regulate transcripts of Cu-containing proteins, and were down-regulated by Fe deficiency, suggesting that they could be involved in plant adaptation to Fe limitation. Indeed, Fe deficiency led to accumulation of Cu in rosettes, prior to any detectable decrease in Fe concentration. ccs1 mutants that lack functional Cu,ZnSOD proteins were prone to greater oxidative stress under Fe deficiency, indicating that increased Cu concentration under Fe limitation has an important role in oxidative stress prevention. The present results show that Cu accumulation, microRNA regulation, and associated differential expression of Fe and CuSOD genes are coordinated responses to Fe limitation. PMID:22962679

Efficiency of a zinc lignosulfonate as Zn source for wheat (Triticum aestivum L.) and corn (Zea mays L.) under hydroponic culture conditions.

PubMed

Martín-Ortiz, Diego; Hernández-Apaolaza, Lourdes; Gárate, Agustin

2009-01-14

The objective of this study was to evaluate the efficiency of a zinc lignosulfonate (ZnLS) as Zn source for wheat and corn plants under hydroponic conditions. The Zn-complexing capacity of three commercial lignosulfonates (byproducts of the paper and pulp industry) was tested, and a LS-NH4, from spruce wood, was selected. Its efficacy as Zn fertilizer for wheat and corn plants was assessed at different pH values (7.0 and 8.0) in comparison with a chelate (ZnEDTA) and an inorganic salt (ZnSO4). For wheat at pH 7.0, it was concluded that the efficacy of the Zn fertilizers followed the sequence Zn-EDTA > Zn-LS approximately ZnSO4 > zero-Zn; and for wheat and corn at pH 8.0, similar results were obtained: Zn-LS > ZnSO4 approximately 0 Zn. These data give evidence that ZnLS could be used as Zn source to the roots of wheat and corn and seems to be more efficient than ZnSO4 to correct Zn deficiency in both plants.

The respective effects of soil heavy metal fractions by sequential extraction procedure and soil properties on the accumulation of heavy metals in rice grains and brassicas.

PubMed

Xiao, Ling; Guan, Dongsheng; Peart, M R; Chen, Yujuan; Li, Qiqi

2017-01-01

This study was carried out to examine heavy metal accumulation in rice grains and brassicas and to identify the different controls, such as soil properties and soil heavy metal fractions obtained by the Community Bureau of Reference (BCR) sequential extraction, in their accumulation. In Guangdong Province, South China, rice grain and brassica samples, along with their rhizospheric soil, were collected from fields on the basis of distance downstream from electroplating factories, whose wastewater was used for irrigation. The results showed that long-term irrigation using the electroplating effluent has not only enriched the rhizospheric soil with Cd, Cr, Cu, and Zn but has also increased their mobility and bioavailability. The average concentrations of Cd and Cr in rice grains and brassicas from closest to the electroplating factories were significantly higher than those from the control areas. Results from hybrid redundancy analysis (hRDA) and redundancy analysis (RDA) showed that the BCR fractions of soil heavy metals could explain 29.0 and 46.5 % of total eigenvalue for heavy metal concentrations in rice grains and brassicas, respectively, while soil properties could only explain 11.1 and 33.4 %, respectively. This indicated that heavy metal fractions exerted more control upon their concentrations in rice grains and brassicas than soil properties. In terms of metal interaction, an increase of residual Zn in paddy soil or a decrease of acid soluble Cd in the brassica soil could enhance the accumulation of Cd, Cu, Cr, and Pb in both rice grains and brassicas, respectively, while the reducible or oxidizable Cd in soil could enhance the plants' accumulation of Cr and Pb. The RDA showed an inhibition effect of sand content and CFO on the accumulation of heavy metals in rice grains and brassicas. Moreover, multiple stepwise linear regression could offer prediction for Cd, Cu, Cr, and Zn concentrations in the two crops by soil heavy metal fractions and soil properties.

Lodging Resistance of Japonica Rice (Oryza Sativa L.): Morphological and Anatomical Traits due to top-Dressing Nitrogen Application Rates.

PubMed

Zhang, Wujun; Wu, Longmei; Wu, Xiaoran; Ding, Yanfeng; Li, Ganghua; Li, Jingyong; Weng, Fei; Liu, Zhenghui; Tang, She; Ding, Chengqiang; Wang, Shaohua

2016-12-01

Lodging in rice production often limits grain yield and quality by breaking or bending stems. Excessive nitrogen (N) fertilizer rates are the cause of poor lodging resistance in rice, but little is known about the effect of top-dressing N application rates on the mechanical strength of japonica rice plants, especially how the anatomical structure in culms is affected by N. In this study, field experiments on two japonica rice varieties with three top-dressing N application rates, 0 kg N ha(-1) (LN), 135 kg N ha(-1) (MN), and 270 kg N ha(-1) (HN) as urea, were conducted. Wuyunjing23, a lodging-resistant japonica rice cultivar and W3668, a lodging-susceptible japonica rice cultivar were used. The lodging index, breaking strength, morphological and anatomical traits in culms were measured in this study. The visual lodging rate in japonica rice differed remarkably between genotypes and top-dressing N treatments. The higher lodging index of rice plants was primarily attributed to the weak breaking strength of the lower internodes. The longer elongated basal internodes were responsible for higher plant height and a higher lodging index. Correlation analysis showed that breaking strength was significantly and positively correlated with the thickness of the mechanical tissue but was significantly and negatively correlated with the inner diameter of the major axis (b2). With increasing top-dressing N rates, the sclerenchyma cells of the mechanical tissues and the vascular bundles of the Wuyunjing23 cultivar varied little. The plant height, inner diameter of the minor axis (a2) and b2 increased significantly, but the area of the large vascular bundle (ALVB) and the area of the small vascular bundle (ASVB) decreased significantly and resulted in lower stem strength and a higher lodging index under higher top-dressing N conditions. The culm diameter of the W3668 cultivar increased slightly with no significant difference, and the sclerenchyma cells in the mechanical tissues and vascular bundles showed deficient lignifications under high top-dressing N conditions. Moreover, the ALVB and the ASVB decreased significantly, while the area of air chambers (AAC) increased rapidly. An improvement in the lodging resistance of japonica rice plants could be achieved by reducing the length of the lower internodes, decreasing the inner culm diameter and developing a thicker mechanical tissue. Top-dressing N application increased the plant height and inner culm diameter and decreased the ALVB and the ASVB of the Wuyunjing23 cultivar and caused deficient lignified sclerenchyma cells, lowered the ALVB and the ASVB, and increased the AAC of the W3668 cultivar resulting in weaker stem strength and a higher lodging index.

The De-Etiolated 1 Homolog of Arabidopsis Modulates the ABA Signaling Pathway and ABA Biosynthesis in Rice

PubMed Central

Zang, Guangchao; Zou, Hanyan; Zhang, Yuchan; Xiang, Zheng; Huang, Junli; Luo, Li; Wang, Chunping; Lei, Kairong; Li, Xianyong; Song, Deming; Din, Ahmad Ud; Wang, Guixue

2016-01-01

DEETIOLATED1 (DET1) plays a critical role in developmental and environmental responses in many plants. To date, the functions of OsDET1 in rice (Oryza sativa) have been largely unknown. OsDET1 is an ortholog of Arabidopsis (Arabidopsis thaliana) DET1. Here, we found that OsDET1 is essential for maintaining normal rice development. The repression of OsDET1 had detrimental effects on plant development, and leaded to contradictory phenotypes related to abscisic acid (ABA) in OsDET1 interference (RNAi) plants. We found that OsDET1 is involved in modulating ABA signaling in rice. OsDET1 RNAi plants exhibited an ABA hypersensitivity phenotype. Using yeast two-hybrid (Y2H) and bimolecular fluorescence complementation assays, we determined that OsDET1 interacts physically with DAMAGED-SPECIFIC DNA-BINDING PROTEIN1 (OsDDB1) and CONSTITUTIVE PHOTOMORPHOGENIC10 (COP10); DET1- and DDB1-ASSOCIATED1 binds to the ABA receptors OsPYL5 and OsDDB1. We found that the degradation of OsPYL5 was delayed in OsDET1 RNAi plants. These findings suggest that OsDET1 deficiency disturbs the COP10-DET1-DDB1 complex, which is responsible for ABA receptor (OsPYL) degradation, eventually leading to ABA sensitivity in rice. Additionally, OsDET1 also modulated ABA biosynthesis, as ABA biosynthesis was inhibited in OsDET1 RNAi plants and promoted in OsDET1-overexpressing transgenic plants. In conclusion, our data suggest that OsDET1 plays an important role in maintaining normal development in rice and mediates the cross talk between ABA biosynthesis and ABA signaling pathways in rice. PMID:27208292

Rice: Characterizing the Environmental Response of a Gibberellic Acid-Deficient Rice for Use as a Model Crop

NASA Technical Reports Server (NTRS)

Frantz, Jonathan M.; Pinnock, Derek; Klassen, Steve; Bugbee, Bruce

2004-01-01

Rice (Oryza sativa L.) is a useful model crop plant. Rice was the first crop plant to have its complete genome sequenced. Unfortunately, even semi-dwarf rice cultivars are 60 to 90 an tail, and large plant populations cannot be grown in the confined volumes of greenhouses and growth chambers. We recently identified an extremely short (20 em tall) rice line, which is an ideal model for larger rice cultivars. We called this line "Super Dwarf rice." Here we report the response of Super Dwarf to temperature, photoperiod, photosynthetic photon flux (PPF), and factors that can affect time to head emergence. Vegetative biomass increased 6% per degree Celsius, with increasing temperature from 27 to 31 C. Seed yield decreased by 2% per degree Celsius rise in temperature, and as a result, harvest index decreased from 60 to 54%. The time to heading increased by 2 d for every hour above a 12-h photoperiod. Yield increased with increasing PPF up to the highest level tested at 1800 micro-mol/sq m/s (12-h photoperiod; 77.8 mol/sq m/d). Yield efficiency (grams per mole of photons) increased to 900 micro-mol/sq m/s and then slightly decreased at 1800 micro-mol/sq m/s . Heading was delayed by addition of gibberellic acid 3 (GA,) to the root zone but was hastened under mild N stress. Overall, short stature, high yield, high harvest index, and no extraordinary environmental requirements make Super Dwarf rice an excellent model plant for yield studies in controlled environments.

Overexpression of folate biosynthesis genes in rice (Oryza sativa L.) and evaluation of their impact on seed folate content.

PubMed

Dong, Wei; Cheng, Zhi-jun; Lei, Cai-lin; Wang, Xiao-le; Wang, Jiu-lin; Wang, Jie; Wu, Fu-qing; Zhang, Xin; Guo, Xiu-ping; Zhai, Hu-qu; Wan, Jian-min

2014-12-01

Folate (vitamin B9) deficiency is a global health problem especially in developing countries where the major staple foods such as rice contain extremely low folates. Biofortification of rice could be an alternative complement way to fight folate deficiency. In this study, we evaluated the availability of the genes in each step of folate biosynthesis pathway for rice folate enhancement in the japonica variety kitaake genetic background. The first enzymes GTP cyclohydrolase I (GTPCHI) and aminodeoxychorismate synthase (ADCS) in the pterin and para-aminobenzoate branches resulted in significant increase in seed folate content, respectively (P < 0.01). Overexpression of two closely related enzymes dihydrofolate synthase (DHFS) and folypolyglutamate synthase (FPGS), which perform the first and further additions of glutamates, produced slightly increase in seed folate content separately. The GTPCHI transgene was combined with each of the other transgenes except ADCS to investigate the effects of gene stacking on seed folate accumulation. Seed folate contents in the gene-stacked plants were higher than the individual low-folate transgenic parents, but lower than the high-folate GTPCHI transgenic lines, pointing to an inadequate supply of para-aminobenzoic acid (PABA) precursor initiated by ADCS in constraining folate overproduction in gene-stacked plants.

Rehabilitating acid soils for increasing crop productivity through low-cost liming material.

PubMed

Bhat, Javid Ahmad; Kundu, Manik Chandra; Hazra, Gora Chand; Santra, Gour Hari; Mandal, Biswapati

2010-09-15

Productivity of red and lateritic soils is low because of their acidity and deficiencies in few essential nutrients viz., nitrogen, phosphorus, calcium, zinc, boron, molybdenum etc. We compared the effectiveness of basic slag, a low-cost liming material, with that of calcite as an ameliorant for these soils using mustard followed by rice as test crops. Experiments were conducted with three levels of each of basic slag and calcite along with a control on farmers' fields at 14 different locations. Influence of farmyard manure (FYM) and poultry manure (PM) on the effectiveness of the slag was also tested. On an average, basic slag performed better than calcite in increasing yields of both mustard and rice and left over higher amounts of available Ca, Si and Zn in residual soils. The slag also improved N, P, K and Ca nutrition of mustard and Si and Zn nutrition of rice with a favorable benefit:cost (B:C) ratio over the calcite (4.82 vs. 1.44). Effectiveness of the basic slag improved when it was applied in combination with FYM or PM (B:C, 5.83 and 6.27). Basic slag can, therefore, be advocated for use in the acidic red and lateritic soils for economically improving their productivity. Copyright 2010 Elsevier B.V. All rights reserved.

In situ stabilization of heavy metals in multiple-metal contaminated paddy soil using different steel slag-based silicon fertilizer.

PubMed

Ning, Dongfeng; Liang, Yongchao; Song, Alin; Duan, Aiwang; Liu, Zhandong

2016-12-01

Steel slag has been widely used as amendment and silicon fertilizer to alleviate the mobility and bioavailability of heavy metals in soil. The objective of this study was to evaluate the influence of particle size, composition, and application rate of slag on metal immobilization in acidic soil, metals uptake by rice and rice growth. The results indicated that application of slag increased soil pH, plant-available silicon concentrations in soil, and decreased the bioavailability of metals compared with control treatment, whereas pulverous slag (S1) was more effective than granular slag (S2 and S3). The acid-extractable fraction of Cd in the spiked soil was significantly decreased with application of S1 at rates of 1 and 3 %, acid-extractable fractions of Cu and Zn were decreased when treated at 3 %. Use of S1 at both rates resulted in significantly lower Cd, Cu, and Zn concentrations in rice tissues than in controls by 82.6-92.9, 88.4-95.6, and 67.4-81.4 %, respectively. However, use of pulverous slag at 1 % significantly promotes rice growth, restricted rice growth when treated at 3 %. Thus, the results explained that reduced particle size and suitable application rate of slag could be beneficial to rice growth and metals stabilization.

The Os-AKT1 Channel Is Critical for K+ Uptake in Rice Roots and Is Modulated by the Rice CBL1-CIPK23 Complex[W][OPEN

PubMed Central

Li, Juan; Long, Yu; Qi, Guo-Ning; Li, Juan; Xu, Zi-Jian; Wu, Wei-Hua; Wang, Yi

2014-01-01

Potassium (K+) is one of the essential nutrient elements for plant growth and development. Plants absorb K+ ions from the environment via root cell K+ channels and/or transporters. In this study, the Shaker K+ channel Os-AKT1 was characterized for its function in K+ uptake in rice (Oryza sativa) roots, and its regulation by Os-CBL1 (Calcineurin B-Like protein1) and Os-CIPK23 (CBL-Interacting Protein Kinase23) was investigated. As an inward K+ channel, Os-AKT1 could carry out K+ uptake and rescue the low-K+-sensitive phenotype of Arabidopsis thaliana akt1 mutant plants. Rice Os-akt1 mutant plants showed decreased K+ uptake and displayed an obvious low-K+-sensitive phenotype. Disruption of Os-AKT1 significantly reduced the K+ content, which resulted in inhibition of plant growth and development. Similar to the AKT1 regulation in Arabidopsis, Os-CBL1 and Os-CIPK23 were identified as the upstream regulators of Os-AKT1 in rice. The Os-CBL1-Os-CIPK23 complex could enhance Os-AKT1-mediated K+ uptake. A phenotype test confirmed that Os-CIPK23 RNAi lines exhibited similar K+-deficient symptoms as the Os-akt1 mutant under low K+ conditions. These findings demonstrate that Os-AKT1-mediated K+ uptake in rice roots is modulated by the Os-CBL1-Os-CIPK23 complex. PMID:25096783

Elevated nicotianamine levels in Arabidopsis halleri roots play a key role in zinc hyperaccumulation.

PubMed

Deinlein, Ulrich; Weber, Michael; Schmidt, Holger; Rensch, Stefan; Trampczynska, Aleksandra; Hansen, Thomas H; Husted, Søren; Schjoerring, Jan K; Talke, Ina N; Krämer, Ute; Clemens, Stephan

2012-02-01

Zn deficiency is among the leading health risk factors in developing countries. Breeding of Zn-enriched crops is expected to be facilitated by molecular dissection of plant Zn hyperaccumulation (i.e., the ability of certain plants to accumulate Zn to levels >100-fold higher than normal plants). The model hyperaccumulators Arabidopsis halleri and Noccaea caerulescens share elevated nicotianamine synthase (NAS) expression relative to nonaccumulators among a core of alterations in metal homeostasis. Suppression of Ah-NAS2 by RNA interference (RNAi) resulted in strongly reduced root nicotianamine (NA) accumulation and a concomitant decrease in root-to-shoot translocation of Zn. Speciation analysis by size-exclusion chromatography coupled to inductively coupled plasma mass spectrometry showed that the dominating Zn ligands in roots were NA and thiols. In NAS2-RNAi plants, a marked increase in Zn-thiol species was observed. Wild-type A. halleri plants cultivated on their native soil showed elemental profiles very similar to those found in field samples. Leaf Zn concentrations in NAS2-RNAi lines, however, did not reach the Zn hyperaccumulation threshold. Leaf Cd accumulation was also significantly reduced. These results demonstrate a role for NAS2 in Zn hyperaccumulation also under near-natural conditions. We propose that NA forms complexes with Zn(II) in root cells and facilitates symplastic passage of Zn(II) toward the xylem.

Elevated Nicotianamine Levels in Arabidopsis halleri Roots Play a Key Role in Zinc Hyperaccumulation[W

PubMed Central

Deinlein, Ulrich; Weber, Michael; Schmidt, Holger; Rensch, Stefan; Trampczynska, Aleksandra; Hansen, Thomas H.; Husted, Søren; Schjoerring, Jan K.; Talke, Ina N.; Krämer, Ute; Clemens, Stephan

2012-01-01

Zn deficiency is among the leading health risk factors in developing countries. Breeding of Zn-enriched crops is expected to be facilitated by molecular dissection of plant Zn hyperaccumulation (i.e., the ability of certain plants to accumulate Zn to levels >100-fold higher than normal plants). The model hyperaccumulators Arabidopsis halleri and Noccaea caerulescens share elevated nicotianamine synthase (NAS) expression relative to nonaccumulators among a core of alterations in metal homeostasis. Suppression of Ah-NAS2 by RNA interference (RNAi) resulted in strongly reduced root nicotianamine (NA) accumulation and a concomitant decrease in root-to-shoot translocation of Zn. Speciation analysis by size-exclusion chromatography coupled to inductively coupled plasma mass spectrometry showed that the dominating Zn ligands in roots were NA and thiols. In NAS2-RNAi plants, a marked increase in Zn-thiol species was observed. Wild-type A. halleri plants cultivated on their native soil showed elemental profiles very similar to those found in field samples. Leaf Zn concentrations in NAS2-RNAi lines, however, did not reach the Zn hyperaccumulation threshold. Leaf Cd accumulation was also significantly reduced. These results demonstrate a role for NAS2 in Zn hyperaccumulation also under near-natural conditions. We propose that NA forms complexes with Zn(II) in root cells and facilitates symplastic passage of Zn(II) toward the xylem. PMID:22374395

Serobactins-mediated iron acquisition systems optimize competitive fitness of Herbaspirillum seropedicae inside rice plants.

PubMed

Rosconi, Federico; Trovero, María F; de Souza, Emanuel M; Fabiano, Elena

2016-09-01

Herbaspirillum seropedicae Z67 is a diazotrophic endophyte able to colonize the interior of many economically relevant crops such as rice, wheat, corn and sorghum. Under iron-deficient conditions, this organism secretes serobactins, a suite of lipopetide siderophores. The role of siderophores in the interaction between endophytes and their plant hosts are not well understood. In this work, we aimed to determine the importance of serobactins-mediated iron acquisition systems in the interaction of H. seropedicae with rice plants. First we provide evidence, by using a combination of genome analysis, proteomic and genetic studies, that the Hsero_2345 gene encodes a TonB-dependent receptor involved in iron-serobactin complex internalization when iron bioavailability is low. Our results show that survival of the Hsero_2345 mutant inside rice plants was not significantly different from that of the wild-type strain. However, when plants were co-inoculated at equal ratios with the wild-type strain and with a double mutant defective in serobactins synthesis and internalization, recovery of mutant was significantly impaired after 8 days post-inoculation. These results demonstrate that serobactins-mediated iron acquisition contributes to competitive fitness of H. seropedicae inside host plants. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

Potential risks of copper, zinc, and cadmium pollution due to pig manure application in a soil-rice system under intensive farming: a case study of Nanhu, China.

PubMed

Shi, Jiachun; Yu, Xiulin; Zhang, Mingkui; Lu, Shenggao; Wu, Weihong; Wu, Jianjun; Xu, Jianming

2011-01-01

Heavy metal (copper [Cu], zinc [Zn], and cadmium [Cd]) pollution of soils from pig manures in soil-rice ( L.) systems under intensive farming was investigated, taking Nanhu, China, as the case study area. Two hundred pig manures and 154 rice straws, brown rice samples, and corresponding surface soil (0-15 cm) samples were collected in paddy fields from 150 farms in 16 major villages within the study area. The mean Cu and Zn concentrations in pig manures consistently exceeded the related standard. About 44 and 60% of soil samples exceed the Chinese Soil Cu and Cd Environmental Quality Standards, respectively. The concentration of Cu, Zn, and Cd in brown rice did not exceed the Chinese Food Hygiene Standard. There was a significant positive correlation between total Cu and Zn contents in soil and application rate of pig manures. Strong correlation was observed between the extractable Cu, Zn, and Cd in soil and the Cu, Zn, and Cd contents in the brown rice. The spatial distribution maps of Cu and Zn concentrations in brown rice, straw, and extractable soil Cu and Zn concentration also showed similar geographical trends. Further analyses on heavy metals loading flux and accumulation rates from pig manure applied suggested that Cu and Cd contents in soil currently have already exceeded the maximum permissible limit, and Zn, if still at current manure application rates, will reach the ceiling concentration limits in 9 yr. This study assists in understanding the risk of heavy metals accumulating from pig manure applications to agricultural soils. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Open-pit coal-mining effects on rice paddy soil composition and metal bioavailability to Oryza sativa L. plants in Cam Pha, northeastern Vietnam.

PubMed

Martinez, Raul E; Marquez, J Eduardo; Hòa, Hoàng Thị Bích; Gieré, Reto

2013-11-01

This study quantified Cd, Pb, and Cu content, and the soil-plant transfer factors of these elements in rice paddies within Cam Pha, Quang Ninh province, northeastern Vietnam. The rice paddies are located at a distance of 2 km from the large Coc Sau open-pit coal mine. Electron microprobe analysis combined with backscattered electron imaging and energy-dispersive spectroscopy revealed a relatively high proportion of carbon particles rimmed by an iron sulfide mineral (probably pyrite) in the quartz-clay matrix of rice paddy soils at 20-30 cm depth. Bulk chemical analysis of these soils revealed the presence of Cd, Cu, and Pb at concentrations of 0.146±0.004, 23.3±0.1, and 23.5±0.1 mg/kg which exceeded calculated background concentrations of 0.006±0.004, 1.9±0.5, and 2.4±1.5 mg/kg respectively at one of the sites. Metals and metalloids in Cam Pha rice paddy soils, including As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, and Zn, were found in concentrations ranging from 0.2±0.1 to 140±3 mg/kg, which were in close agreement with toxic metal contents in mine tailings and Coc Sau coal samples, suggesting mining operations as a major cause of paddy soil contamination. Native and model Oryza sativa L. rice plants were grown in the laboratory in a growth medium to which up to 1.5 mg/kg of paddy soil from Cam Pha was added to investigate the effects on plant growth. A decrease in growth by up to 60% with respect to a control sample was found for model plants, whereas a decrease of only 10% was observed for native (Nep cai hoa vang variety) rice plants. This result suggests an adaptation of native Cam Pha rice plants to toxic metals in the agricultural lands. The Cd, Cu, and Pb contents of the native rice plants from Cam Pha paddies exceeded permitted levels in foods. Cadmium and Pb were highest in the rice plant roots with concentrations of 0.84±0.02 and 7.7±0.3 mg/kg, suggesting an intake of these metals into the rice plant as shown, for example, by Cd and Pb concentrations of 0.09±0.01 and 0.10±0.04 mg/kg respectively in the rice grain endosperm. The adaptation of native rice plants, combined with bioaccumulation ratios of 1±0.6 to 1.4±0.7 calculated for Cd transfer to the rice grain endosperm, and maximum Cd transfer factors of 4.3±2.1 to the plant roots, strongly suggest a continuous input of some toxic metals from coal-mining operations to agricultural lands in the region of Cam Pha. In addition, our results imply a sustained absorption of metals by native rice plant varieties, which may lead to metal accumulation (e.g., Cd) in human organs and in turn to severe disease.

Lack of Zn inhibition of Cd accumulation by rice (Oryza sativa L.) supports non-Zn transporter uptake of Cd

USDA-ARS?s Scientific Manuscript database

Rice (Oryza sativa L.) grown on Cd contaminated soils has been linked to health problems in subsistence rice farmers in Japan and China. For other crops, normal geogenic Zn inhibits the increased uptake of Cd on contaminated soils. A study was conducted using a multi-chelator buffered nutrient sol...

Prioritizing plant defence over growth through WRKY regulation facilitates infestation by non-target herbivores.

PubMed

Li, Ran; Zhang, Jin; Li, Jiancai; Zhou, Guoxin; Wang, Qi; Bian, Wenbo; Erb, Matthias; Lou, Yonggen

2015-06-17

Plants generally respond to herbivore attack by increasing resistance and decreasing growth. This prioritization is achieved through the regulation of phytohormonal signaling networks. However, it remains unknown how this prioritization affects resistance against non-target herbivores. In this study, we identify WRKY70 as a specific herbivore-induced, mitogen-activated protein kinase-regulated rice transcription factor that physically interacts with W-box motives and prioritizes defence over growth by positively regulating jasmonic acid (JA) and negatively regulating gibberellin (GA) biosynthesis upon attack by the chewing herbivore Chilo suppressalis. WRKY70-dependent JA biosynthesis is required for proteinase inhibitor activation and resistance against C. suppressalis. In contrast, WRKY70 induction increases plant susceptibility against the rice brown planthopper Nilaparvata lugens. Experiments with GA-deficient rice lines identify WRKY70-dependent GA signaling as the causal factor in N. lugens susceptibility. Our study shows that prioritizing defence over growth leads to a significant resistance trade-off with important implications for the evolution and agricultural exploitation of plant immunity.

Characterization of a putative grapevine Zn transporter, VvZIP3, suggests its involvement in early reproductive development in Vitis vinifera L

PubMed Central

2012-01-01

Background Zinc (Zn) deficiency is one of the most widespread mineral nutritional problems that affect normal development in plants. Because Zn cannot passively diffuse across cell membranes, it must be transported into intracellular compartments for all biological processes where Zn is required. Several members of the Zinc-regulated transporters, Iron-regulated transporter-like Protein (ZIP) gene family have been characterized in plants, and have shown to be involved in metal uptake and transport. This study describes the first putative Zn transporter in grapevine. Unravelling its function may explain an important symptom of Zn deficiency in grapevines, which is the production of clusters with fewer and usually smaller berries than normal. Results We identified and characterized a putative Zn transporter from berries of Vitis vinifera L., named VvZIP3. Compared to other members of the ZIP family identified in the Vitis vinifera L. genome, VvZIP3 is mainly expressed in reproductive tissue - specifically in developing flowers - which correlates with the high Zn accumulation in these organs. Contrary to this, the low expression of VvZIP3 in parthenocarpic berries shows a relationship with the lower Zn accumulation in this tissue than in normal seeded berries where its expression is induced by Zn. The predicted protein sequence indicates strong similarity with several members of the ZIP family from Arabidopsis thaliana and other species. Moreover, VvZIP3 complemented the growth defect of a yeast Zn-uptake mutant, ZHY3, and is localized in the plasma membrane of plant cells, suggesting that VvZIP3 has the function of a Zn uptake transporter. Conclusions Our results suggest that VvZIP3 encodes a putative plasma membrane Zn transporter protein member of the ZIP gene family that might play a role in Zn uptake and distribution during the early reproductive development in Vitis vinifera L., indicating that the availability of this micronutrient may be relevant for reproductive development. PMID:22824090

Characterization of a putative grapevine Zn transporter, VvZIP3, suggests its involvement in early reproductive development in Vitis vinifera L.

PubMed

Gainza-Cortés, Felipe; Pérez-Dïaz, Ricardo; Pérez-Castro, Ramón; Tapia, Jaime; Casaretto, José A; González, Sebastián; Peña-Cortés, Hugo; Ruiz-Lara, Simón; González, Enrique

2012-07-23

Zinc (Zn) deficiency is one of the most widespread mineral nutritional problems that affect normal development in plants. Because Zn cannot passively diffuse across cell membranes, it must be transported into intracellular compartments for all biological processes where Zn is required. Several members of the Zinc-regulated transporters, Iron-regulated transporter-like Protein (ZIP) gene family have been characterized in plants, and have shown to be involved in metal uptake and transport. This study describes the first putative Zn transporter in grapevine. Unravelling its function may explain an important symptom of Zn deficiency in grapevines, which is the production of clusters with fewer and usually smaller berries than normal. We identified and characterized a putative Zn transporter from berries of Vitis vinifera L., named VvZIP3. Compared to other members of the ZIP family identified in the Vitis vinifera L. genome, VvZIP3 is mainly expressed in reproductive tissue - specifically in developing flowers - which correlates with the high Zn accumulation in these organs. Contrary to this, the low expression of VvZIP3 in parthenocarpic berries shows a relationship with the lower Zn accumulation in this tissue than in normal seeded berries where its expression is induced by Zn. The predicted protein sequence indicates strong similarity with several members of the ZIP family from Arabidopsis thaliana and other species. Moreover, VvZIP3 complemented the growth defect of a yeast Zn-uptake mutant, ZHY3, and is localized in the plasma membrane of plant cells, suggesting that VvZIP3 has the function of a Zn uptake transporter. Our results suggest that VvZIP3 encodes a putative plasma membrane Zn transporter protein member of the ZIP gene family that might play a role in Zn uptake and distribution during the early reproductive development in Vitis vinifera L., indicating that the availability of this micronutrient may be relevant for reproductive development.

Mechanisms of Fe biofortification and mitigation of Cd accumulation in rice (Oryza sativa L.) grown hydroponically with Fe chelate fertilization.

PubMed

Chen, Zhe; Tang, Ye-Tao; Zhou, Can; Xie, Shu-Ting; Xiao, Shi; Baker, Alan J M; Qiu, Rong-Liang

2017-05-01

Cadmium contaminated rice from China has become a global food safety issue. Some research has suggested that chelate addition to substrates can affect metal speciation and plant metal content. We investigated the mitigation of Cd accumulation in hydroponically-grown rice supplied with EDTANa 2 Fe(II) or EDDHAFe(III). A japonica rice variety (Nipponbare) was grown in modified Kimura B solution containing three concentrations (0, 10, 100 μΜ) of the iron chelates EDTANa 2 Fe(II) or EDDHAFe(III) and 1 μΜ Cd. Metal speciation in solution was simulated by Geochem-EZ; growth and photosynthetic efficiency of rice were evaluated, and accumulation of Cd and Fe in plant parts was determined. Net Cd fluxes in the meristematic zone, growth zone, and maturation zone of roots were monitored by a non-invasive micro-test technology. Expression of Fe- and Cd-related genes in Fe-sufficient or Fe-deficient roots and leaves were studied by QRT-PCR. Compared to Fe deficiency, a sufficient or excess supply of Fe chelates significantly enhanced rice growth by elevating photosynthetic efficiency. Both Fe chelates increased the Fe content and decreased the Cd content of rice organs, except for the Cd content of roots treated with excess EDDHAFe(III). Compared to EDDHAFe(III), EDTANa 2 Fe(II) exhibited better mitigation of Cd accumulation in rice by generating the EDTANa 2 Cd complex in solution, decreasing net Cd influx and increasing net Cd efflux in root micro-zones. Application of EDTANa 2 Fe(II) and EDDHAFe(III) also reduced Cd accumulation in rice by inhibiting expression of genes involved in transport of Fe and Cd in the xylem and phloem. The 'win-win' situation of Fe biofortification and Cd mitigation in rice was achieved by application of Fe chelates. Root-to-stem xylem transport of Cd and redistribution of Cd in leaves by phloem transport can be regulated in rice through the use of Fe chelates that influence Fe availability and Fe-related gene expression. Fe fertilization decreased Cd influx and increased Cd efflux in rice roots. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sorption kinetics of Zn (II) ion by thermally treated rice husk

NASA Astrophysics Data System (ADS)

Ong, K. K.; Tarmizi, A. F. A.; Wan Yunus W. M., Z.; Safidin, K. M.; Fitrianto, A.; Hussin, A. G. A.; Azmi, F. M.

2015-05-01

Agricultural wastes such as orange peels, tea leave waste, rice husk and corn cobs have been widely studied as sorbents for heavy metal ion removal from various wastewaters. In order to understand their sorption mechanism, the adsorption kinetics is studied. This report describes the kinetics study of a thermally treated rice husk to adsorb Zn (II) ion from an aqueous solution. The adsorbent was obtained by heating the rice husk in a furnace at 500°C for two hours. Increase the contact period improved percentage of the removal of Zn (II) ion until an equilibrium was reached. The data obtained showed that the adsorption of Zn (II) ion by thermally treated rice husk obeyed pseudo-second order kinetics model, which is in agreement with chemisorption as the rate limiting mechanism.

Nutrient status and plant growth effects of forest soils in the Basin of Mexico

Treesearch

Mark E. Fenn; V.M. Perea-Estrada; L.I. de Bauer; M. Pérez-Suárez; D.R. Parker; V.M. Cetina-Alcalá

2006-01-01

The nutrient status of forest soils in the Mexico City Air Basin was evaluated by observing plant growth responses to fertilization with N, P or both nutrients combined. P deficiency was the most frequent condition for soil from two high pollution sites and N deficiency was greatest at a low N deposition site. Concentrations of Pb and Ni, and to a lesser extent Zn and...

Selenite modulates the level of phenolics and nutrient element to alleviate the toxicity of arsenite in rice (Oryza sativa L.).

PubMed

Chauhan, Reshu; Awasthi, Surabhi; Tripathi, Preeti; Mishra, Seema; Dwivedi, Sanjay; Niranjan, Abhishek; Mallick, Shekhar; Tripathi, Pratibha; Pande, Veena; Tripathi, Rudra Deo

2017-04-01

Arsenic (As) contamination of paddy rice is a serious threat all over the world particularly in South East Asia. Selenium (Se) plays important role in protection of plants against various abiotic stresses including heavy metals. Moreover, arsenite (AsIII) and selenite (SeIV) can be biologically antagonistic due to similar electronic configuration and sharing the common transporter for their uptake in plant. In the present study, the response of oxidative stress, phenolic compounds and nutrient elements was analyzed to investigate Se mediated As tolerance in rice seedlings during AsIII and SeIV exposure in hydroponics. Selenite (25µM) significantly decreased As accumulation in plant than As (25µM) alone treated plants. Level of oxidative stress related parameters viz., reactive oxygen species (ROS), lipid peroxidation, electrical conductivity, nitric oxide and pro-oxidant enzyme (NADPH oxidase), were in the order of As>As+Se>control>Se. Selenium ameliorated As phytotoxicity by increased level of phenolic compounds particularly gallic acid, protocatechuic acid, ferulic acid and rutin and thiol metabolism related enzymes viz., serine acetyl transferase (SAT) and cysteine synthase (CS). Selenium supplementation enhanced the uptake of nutrient elements viz., Fe, Mn, Co, Cu, Zn, Mo, and improved plant growth. The results concluded that Se addition in As contaminated environment might be an important strategy to reduce As uptake and associated phytotoxicity in rice plant by modulation of phenolic compounds and increased uptake of nutrient elements. Copyright © 2016 Elsevier Inc. All rights reserved.

RISK ASSESSMENT FOR CADMIUM IN PHOSPHATE FERTILIZERS

EPA Science Inventory

Cadmium induced renal tubular dysfunction occurred where subsistence rice farmers produced their lifetime dietary rice on Zn-mine waste contaminated soils in Japan and other Asian countries. Research has shown that polished rice Cd is greatly increased while grain Zn is not incre...

Induced Jasmonate Signaling Leads to Contrasting Effects on Root Damage and Herbivore Performance1

PubMed Central

Lu, Jing; Robert, Christelle Aurélie Maud; Riemann, Michael; Cosme, Marco; Mène-Saffrané, Laurent; Massana, Josep; Stout, Michael Joseph; Lou, Yonggen; Gershenzon, Jonathan; Erb, Matthias

2015-01-01

Induced defenses play a key role in plant resistance against leaf feeders. However, very little is known about the signals that are involved in defending plants against root feeders and how they are influenced by abiotic factors. We investigated these aspects for the interaction between rice (Oryza sativa) and two root-feeding insects: the generalist cucumber beetle (Diabrotica balteata) and the more specialized rice water weevil (Lissorhoptrus oryzophilus). Rice plants responded to root attack by increasing the production of jasmonic acid (JA) and abscisic acid, whereas in contrast to in herbivore-attacked leaves, salicylic acid and ethylene levels remained unchanged. The JA response was decoupled from flooding and remained constant over different soil moisture levels. Exogenous application of methyl JA to the roots markedly decreased the performance of both root herbivores, whereas abscisic acid and the ethylene precursor 1-aminocyclopropane-1-carboxylic acid did not have any effect. JA-deficient antisense 13-lipoxygenase (asLOX) and mutant allene oxide cyclase hebiba plants lost more root biomass under attack from both root herbivores. Surprisingly, herbivore weight gain was decreased markedly in asLOX but not hebiba mutant plants, despite the higher root biomass removal. This effect was correlated with a herbivore-induced reduction of sucrose pools in asLOX roots. Taken together, our experiments show that jasmonates are induced signals that protect rice roots from herbivores under varying abiotic conditions and that boosting jasmonate responses can strongly enhance rice resistance against root pests. Furthermore, we show that a rice 13-lipoxygenase regulates root primary metabolites and specifically improves root herbivore growth. PMID:25627217

Nanoscale zinc silicate from phytoliths

NASA Astrophysics Data System (ADS)

Qadri, S. B.; Gorzkowski, E. P.; Rath, B. B.; Feng, C. R.; Amarasinghe, R.; Freitas, J. A.; Culbertson, J. C.; Wollmershauser, J. A.

2017-10-01

We report a faster, less expensive method of producing zinc silicate nanoparticles. Such particles are used in high volume to make phosphors and anti-corrosion coatings. The approach makes use of phytoliths (plant rocks), which are microscopic, amorphous, and largely silicate particles embedded in plants, that lend themselves to being easily broken down into nanoparticles. Nanoparticles of Zn2SiO4 were produced in a two stage process. In the refinement stage, plant residue, mixed with an appropriate amount of ZnO, was heated in an argon atmosphere to a temperature exceeding 1400 °C for four to six hours and then heated in air at 650 °C to remove excess carbon. TEM shows 50-100 nm nanoparticles. Raman scattering indicates that only the -Zn2SiO4 crystalline phase was present. X-ray analysis indicated pure rhombohedral R 3 bar phase results from using rice/wheat husks. Both samples luminesced predominantly at 523 nm when illuminated with X-rays or UV laser light.

How does contamination of rice soils with Cd and Zn cause high incidence of human Cd disease in subsistence rice farmers?

USDA-ARS?s Scientific Manuscript database

Rice (Oryza sativa L.) grown on Zn mine waste contaminated soils has caused unequivocal Cd effects on kidney and occasional bone disease (itai-itai) in subsistence rice farmers, but high intake of Cd from other foods has not caused similar effects. Research has clarified two important topics about ...

Induced jasmonate signaling leads to contrasting effects on root damage and herbivore performance.

PubMed

Lu, Jing; Robert, Christelle Aurélie Maud; Riemann, Michael; Cosme, Marco; Mène-Saffrané, Laurent; Massana, Josep; Stout, Michael Joseph; Lou, Yonggen; Gershenzon, Jonathan; Erb, Matthias

2015-03-01

Induced defenses play a key role in plant resistance against leaf feeders. However, very little is known about the signals that are involved in defending plants against root feeders and how they are influenced by abiotic factors. We investigated these aspects for the interaction between rice (Oryza sativa) and two root-feeding insects: the generalist cucumber beetle (Diabrotica balteata) and the more specialized rice water weevil (Lissorhoptrus oryzophilus). Rice plants responded to root attack by increasing the production of jasmonic acid (JA) and abscisic acid, whereas in contrast to in herbivore-attacked leaves, salicylic acid and ethylene levels remained unchanged. The JA response was decoupled from flooding and remained constant over different soil moisture levels. Exogenous application of methyl JA to the roots markedly decreased the performance of both root herbivores, whereas abscisic acid and the ethylene precursor 1-aminocyclopropane-1-carboxylic acid did not have any effect. JA-deficient antisense 13-lipoxygenase (asLOX) and mutant allene oxide cyclase hebiba plants lost more root biomass under attack from both root herbivores. Surprisingly, herbivore weight gain was decreased markedly in asLOX but not hebiba mutant plants, despite the higher root biomass removal. This effect was correlated with a herbivore-induced reduction of sucrose pools in asLOX roots. Taken together, our experiments show that jasmonates are induced signals that protect rice roots from herbivores under varying abiotic conditions and that boosting jasmonate responses can strongly enhance rice resistance against root pests. Furthermore, we show that a rice 13-lipoxygenase regulates root primary metabolites and specifically improves root herbivore growth. © 2015 American Society of Plant Biologists. All Rights Reserved.

Trace elements in native and improved paddy rice from different climatic regions of Sri Lanka: implications for public health.

PubMed

Diyabalanage, Saranga; Navarathna, Thamara; Abeysundara, Hemalika T K; Rajapakse, Sanath; Chandrajith, Rohana

2016-01-01

Samples of 226 new improved and 21 indigenous rice ( Oryza sativa L.) varieties were collected from the rice fields in three climatic zones of Sri Lanka and concentrations of 18 trace elements (Li, B, Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Mo, Cd, Ba, Pb and Bi) were measured giving particular emphasis on Se, Cd and As using ICP-MS. The two way multivariate analysis of variance (MANOVA) method was employed to identify the differences in composition among rice from different climatic zones. The mean values obtained for both white and red rice were Se (36; 25 µg/kg), As (42; 45 µg/kg) and Cd (70; 123 µg/kg) on dry weight basis. However mean content of Se, As and Cd of native rice varieties were 69, 74 and 33 µg/kg, respectively. Statistical interpretations showed that in the majority of cases, there was a significant difference in Cd content among climatic zones whereas Se and Pb show differences between white and red rice varieties. Arsenic did not indicate any significant difference either between rice types or among climatic regions. Notably Se and As contents in indigenous rice were higher than that of improved rice types. To assess the safety of dietary of intake, daily intake of Se, Cd and As by rice were calculated. Non-gender specific Estimated Daily Intake (EDI) of Se, Cd and As consuming improved rice are 9.31, 24.1 and 12.2 µg day -1 , respectively. Since over 50 % of daily meals of people contain rice or rice based products, Se intake is expected to be deficient among the Sri Lankan population.

Effects of ZnSO4 and Zn-EDTA broadcast or banded to soil on Zn bioavailability in wheat (Triticum aestivum L.) and Zn fractions in soil.

PubMed

Zhao, Aiqing; Yang, Shu; Wang, Bini; Tian, Xiaohong; Zhang, Youlin

2018-08-01

Human Zn deficiency is prevalent in developing countries, and staple grains are commonly bio-fortified to increase their Zn contents. We measured Zn content, distribution, and bioavailability in calcareous soil and in wheat plants (Triticum aestivum L.) in Shaanxi Province, China, when either an organic Zn-ethylenediaminetetraacetate (Zn-EDTA) or an inorganic zinc sulfate heptahydrate (ZnSO 4 ·7H 2 O) Zn source was banded below the seedbed or broadcasted into soil. Compared with ZnSO 4 ·7H 2 O, Zn-EDTA fertilization produced higher Zn concentration and uptake in wheat plants. However, Zn bioavailability in grain remained low, with [phytate]/[Zn] ratio >15 and the resulting estimated dietary total absorbed zinc (TAZ) < 3 mg Zn/d. ZnSO 4 banded into soil had little short-term effect on grain Zn concentration but had a high residual effect and promoted the maintenance of a high concentration of the Zn fraction bound to loose organic matter (LOM-Zn) in rhizosphere soil. Both ZnSO 4 and Zn-EDTA were more efficient if uniformly mixed through the soil than if banded to soil. Both ZnSO 4 and Zn-EDTA had limited effects on Zn bioavailability in wheat plants due to the high rate of Zn fixation in this calcareous soil. Copyright © 2018 Elsevier Ltd. All rights reserved.

Mucin-like protein, a saliva component involved in brown planthopper virulence and host adaptation.

PubMed

Huang, Hai-Jian; Liu, Cheng-Wen; Xu, Hai-Jun; Bao, Yan-Yuan; Zhang, Chuan-Xi

2017-04-01

The rice brown planthopper (BPH), Nilaparvata lugens, can rapidly adapt to new resistant rice varieties within several generations, rendering its management burdensome. However, the molecular mechanism underlying its adaptability remains unclear. In this study, we investigated the potential role of mucin-like protein (NlMul) in N. lugens virulence and adaptation to host resistance. NlMul is an important glycoprotein that constitutes both gelling and watery saliva, and specifically expressed in the salivary glands at all developmental stages except the egg period. Knocking down the expression of NlMul resulted in the secretion of short and single-branched salivary sheaths. NlMul might help BPH deal with plant resistance, and altered gene expression was observed when BPHs were transferred from a susceptible rice variety to a resistant one. The NlMul-deficient BPHs showed disordered developmental duration and a portion of these insects reared on resistant rice exhibited lethal effects. Our results uncover a saliva-mediated interaction between insect and host plant, and provide useful information in rice breeding and planthopper management. Copyright © 2017 Elsevier Ltd. All rights reserved.

X-ray CT imaging and image-based modelling study of gas exchange in the rice rhizosphere

NASA Astrophysics Data System (ADS)

Affholder, Marie-Cecile; Keyes, Samuel David; Roose, Tiina; Heppell, James; Kirk, Guy

2016-04-01

We used X-ray computer tomography and image-based modelling to investigate CO2 uptake by rice roots growing in submerged soil, and its consequences for the chemistry and biology of the rhizosphere. From previous work, three processes are known to greatly modify the rhizophere of rice and other wetland plants: (1) oxygenation of the submerged, anoxic soil by O2 transported through the root gas channels (aerenchyma); (2) oxidation of ferrous iron and resulting accumulation of ferric oxide; and (3) pH changes due to protons formed in iron oxidation and released from the roots to balance excess intake of cations over anions. A further process, so far not much investigated, is the possibility of CO2 uptake by the roots. Large amounts of CO2 accumulate in submerged soils because CO2 formed in soil respiration escapes only slowly by diffusion through the water-saturated soil pores. There is therefore a large CO2 gradient between the soil and the aerenchyma inside the root, and CO2 may be taken up by the roots and vented to the atmosphere. The extent of this and its consequences for rhizosphere chemistry and biology are poorly understood. We grew rice plants in a submerged, strongly-reduced, Philippine rice soil contained in 10-cm diameter, 20-cm deep Perspex pots. Four-week old rice seedlings, grown in nutrient culture, were transplanted into the pots at either 1 or 4 plants per pot, planted closely together. After 3 and 4 weeks, the pots were analysed with an X-ray CT scanner (Custom Nikon/Xtek Hutch; 80 mm by 56 mm field of view and 40 μm voxel size). Gas bubbles were extracted from the data by 3D median filtering and roots using a region-growth method. The images showed prominent and abundant gas bubbles in the soil bulk, but no or very few bubbles in the soil close to roots. There was a clear relation between the absence of gas bubbles and the presence of roots, as well as an increasing concentration of bubbles with depth through the soil. Analysis of the bubbles showed they were approximately 50% CO2 by volume and 50% CH4. The corresponding concentrations of dissolved CO2 + HCO3- (NB CO2 is 20-times more soluble than CH4) in the soil bulk were of the order of 100 mM. We developed a mathematical model of CO2 generation and transport in submerged soil with uptake by and transport through rice roots, and used it to analyse the images. This showed that the observed depletion of CO2 around the roots was consistent with realistic values of parameters for the root gas permeability and rates of CO2 production and diffusion in submerged soil. Depletion of CO2 around the roots will have consequences for the chemistry of the rice rhizosphere and the extent of the root-induced pH changes and other changes listed above. In continuing work we are investigating the implications for the solubility and root uptake of soil Zn, deficiency of which is a widespread constraint to rice growth.

SGD1, a key enzyme in tocopherol biosynthesis, is essential for plant development and cold tolerance in rice.

PubMed

Wang, Di; Wang, Yunlong; Long, Wuhua; Niu, Mei; Zhao, Zhigang; Teng, Xuan; Zhu, Xiaopin; Zhu, Jianping; Hao, Yuanyuan; Wang, Yongfei; Liu, Yi; Jiang, Ling; Wang, Yihua; Wan, Jianmin

2017-07-01

Tocopherols, a group of Vitamin E compounds, are essential components of the human diet. In contrast to well documented roles in animals, the functions of tocopherols in plants are less understood. In this study, we characterized two allelic rice dwarf mutant lines designated sgd1-1 and sgd1-2 (small grain and dwarf1). Histological observations showed that the dwarf phenotypes were mainly due to cell elongation defects. A map-based cloning strategy and subsequent complementation test showed that SGD1 encodes homogentisate phytyltransferase (HPT), a key enzyme in tocopherol biosynthesis. Mutation of SGD1 resulted in tocopherol deficiency in both sgd1mutants. No oxidant damage was detected in the sgd1 mutants. Further analysis showed that sgd1-2 was hypersensitive to cold stress. Our results indicate that SGD1 is essential for plant development and cold tolerance in rice. Copyright © 2017 Elsevier B.V. All rights reserved.

Relationship of ROS accumulation and superoxide dismutase isozymes in developing anther with floret fertility of rice under heat stress.

PubMed

Zhao, Qian; Zhou, Lujian; Liu, Jianchao; Du, Xiaoxia; Asad, Muhammad-Asad-Ullah; Huang, Fudeng; Pan, Gang; Cheng, Fangmin

2018-01-01

High temperature (HT) at meiosis stage is one of most important environment constraint affecting spikelet fertility and rice yield. In this paper, the effects of HT exposure at meiosis stage on the ROS (reactive oxygen species) accumulation, various superoxide dismutase (SOD, EC1.15.1.11) isozymes in developing anther, and its relationship with HT-induced decline in pollen viability and floret fertility were investigated by using four rice cultivars differing in heat tolerance under well-controlled climatic condition. Results showed that HT exposure significantly increased ROS level and malondialdehyde (MDA) content in rice anther, and this occurrence was strongly responsible for the HT-induced decline in pollen viability and harmful effect of HT adversity on floret fertility. However, the increased extent of ROS concentration in rice anther under HT exposure was greatly variable, depending on both the intensity and duration of HT exposure and different rice cultivars used. The SOD and CAT activities of HT-sensitive cultivars decreased more profoundly than those of HT-tolerant cultivars under the same HT regimes. Among various types of SOD enzymes, Cu/Zn-SODa expressed highly in rice anther and responded sensitively to HT exposure, while Cu/Zn-SODb expressed weakly in rice anther and preferentially in rice leaves. HT exposure suppressed the expression of Cu/Zn-SODa in developing anther, which was closely associated with the down-regulated transcripts of cCu/Zn-SOD1 gene. Hence, Cu/Zn-SODa may play a central role in the regulation of total SOD activity and ROS detoxification in rice anther as affected by HT exposure at meiosis stage. Copyright © 2017. Published by Elsevier Masson SAS.

Prioritizing plant defence over growth through WRKY regulation facilitates infestation by non-target herbivores

PubMed Central

Li, Ran; Zhang, Jin; Li, Jiancai; Zhou, Guoxin; Wang, Qi; Bian, Wenbo; Erb, Matthias; Lou, Yonggen

2015-01-01

Plants generally respond to herbivore attack by increasing resistance and decreasing growth. This prioritization is achieved through the regulation of phytohormonal signaling networks. However, it remains unknown how this prioritization affects resistance against non-target herbivores. In this study, we identify WRKY70 as a specific herbivore-induced, mitogen-activated protein kinase-regulated rice transcription factor that physically interacts with W-box motifs and prioritizes defence over growth by positively regulating jasmonic acid (JA) and negatively regulating gibberellin (GA) biosynthesis upon attack by the chewing herbivore Chilo suppressalis. WRKY70-dependent JA biosynthesis is required for proteinase inhibitor activation and resistance against C. suppressalis. In contrast, WRKY70 induction increases plant susceptibility against the rice brown planthopper Nilaparvata lugens. Experiments with GA-deficient rice lines identify WRKY70-dependent GA signaling as the causal factor in N. lugens susceptibility. Our study shows that prioritizing defence over growth leads to a significant resistance trade-off with important implications for the evolution and agricultural exploitation of plant immunity. DOI: http://dx.doi.org/10.7554/eLife.04805.001 PMID:26083713

Identification of gibberellin acid-responsive proteins in rice leaf sheath using proteomics.

PubMed

Gu, Jia-Yu; Wang, Ye; Zhang, Xu; Zhang, Shi-Hua; Gao, Yin; An, Cheng-Cai

2010-06-01

The phytohormone gibberellin acid (GA) controls many aspects of plant development. In this study, we identified proteins that are differentially expressed between the rice (Oryza sativa L.) GA-deficient cultivar, Aijiaonante, and its parental line, Nante. Proteins were extracted from rice leaf sheath and examined by 2DGE. Among more than 1200 protein spots reproducibly detected on each gel, 29 were found to be highly up-regulated by GAs in Nante, and 6 were down-regulated by GAs in Aijiaonante. These 35 proteins were identified by MALDI-TOF MS and were classified into three groups based on their putative function in metabolism, stress/defense processes and signal transduction. These data suggest that metabolic pathways are the main target of regulation by GAs during rice development. Our results provide new information about the involvement of GAs in rice development.

Low uptake affinity cultivars with biochar to tackle Cd-tainted rice--A field study over four rice seasons in Hunan, China.

PubMed

Chen, De; Guo, Hu; Li, Ruiyue; Li, Lianqing; Pan, Genxing; Chang, Andrew; Joseph, Stephen

2016-01-15

Biochar is becoming an environmentally friendly material for remediation of heavy metal contaminated soils and improving food safety. A field trial over four rice seasons was conducted to investigate the use of biochar and low Cd accumulating cultivars on Cd uptake in a heavy metal contaminated soil. Wheat straw derived biochar was applied at 0, 20 and 40 t ha(-1). Two rice cultivars with differing Cd accumulation abilities were selected in each season. The results showed that both biochar and low Cd affinity cultivars significantly reduced rice grain Cd accumulation. Biochar had no significant effect the first season but thereafter consistently reduced rice grain Cd by a maximum of 61, 86 and 57% over the next three seasons. Zn accumulation in the rice grains was not decreased by biochar application, although available soil Zn was sharply reduced (35-91%). Indica conventional rice cultivars had much lower Cd, but higher Zn and lower Cd/Zn ratios in the grain than indica hybrid cultivars. Biochar was more effective for mitigating grain Cd accumulation in low Cd affinity cultivars than in high affinity cultivars. Soil pH was sustainably increased (up to nearly 1 unit) while available Cd significantly decreased by a maximum of 85% after biochar addition. The translocation of Cd from rice roots to shoots was reduced from 20 to 80% by biochar. Low uptake affinity cultivars combined with biochar reduced late rice grain Cd concentration and Cd/Zn ratios by 69-80% and 72-80%, respectively. It indicated that the management of combining biochar and low Cd affinity cultivars should be an efficient way to remediate Cd contaminated rice paddies and reduce health risk associated with consuming rice from these soils. Copyright © 2015 Elsevier B.V. All rights reserved.

Genetic evaluation of recombinant inbred lines of rice (Oryza sativa L.) for grain zinc concentrations, yield related traits and identification of associated SSR markers.

PubMed

Bekele, Berhanu D; Naveen, G K; Rakhi, S; Shashidhar, H E

2013-12-01

The objectives of the present study were to evaluate genetic variability parameters, correlations that exist for grain Zn concentration and yield related traits and identification of SSR markers linked to these traits in rice. One hundred seventy six Recombinant Inbred Lines (RILs) of Azucena X Moromutant were grown at University of Agricultural Sciences, Bangalore in augmented experimental design during wet seasons of 2010 and 2011. The study revealed significant genetic variability for all the traits. Grain yield per plant and grain zinc concentration showed higher phenotypic and genotypic co-efficient of variation. Significant positive correlation was observed for grain yield per plant with number of productive tillers per plant (r = 0.5) and number of tillers per plant (r = 0.4). Grain zinc concentration showed negative correlation with grain yield per plant (r = - 0.27). The path-coefficient analysis indicated the positive direct effect of number of productive tillers per plant on grain yield per plant (0.514). Grain zinc concentration showed negative direct effect on grain yield per plant (-0.186). Single-marker analysis using 26 SSR markers on RILs mapping population showed that RM212, RM263, RM6832, RM152, RM21, RM234 and RM3331 had association with grain zinc concentration and other yield related traits. But validation of these markers on fifty two rice genotypes showed that only three markers RM263, RM152 and RM21 had association with grain zinc concentration. Therefore, the genetic information generated and molecular markers identified from this study could be used for zinc biofortification programmes in rice.

Characterization of plant growth-promoting traits of free-living diazotrophic bacteria and their inoculation effects on growth and nitrogen uptake of crop plants.

PubMed

Islam, Md Rashedul; Madhaiyan, M; Deka Boruah, Hari P; Yim, Woojong; Lee, Gillseung; Saravanan, V S; Fu, Qingling; Hu, Hongqing; Sa, Tongmin

2009-10-01

The search for diverse plant growth-promoting (PGP) diazotrophic bacteria is gaining momentum as efforts are made to exploit them as biofertilizers for various economically important crops. In the present study, 17 diazotrophic strains belonging to eight different genera isolated from rice paddy fields were screened for multiple PGP traits and evaluated for their inoculation effects on canola and rice plants. All of the strains tested positive for 1- aminocyclopropane-1-carboxylate (ACC) deaminase activity and production of indole 3-acetic acid (IAA) and ammonia (NH3). Additionally, four of the strains were able to solubilize phosphorus (P), five tested positive for zinc (Zn) solubilization and sulfur (S) oxidation, and eight strains produced siderophores. Based on the presence of multiple PGP traits, 10 strains were selected for inoculation studies. Treatment with Herbaspirillum sp. RFNB26 resulted in maximum root length (54.3%), seedling vigor, and dry biomass in canola, whereas Paenibacillus sp. RFNB4 exhibited the lowest activity under gnotobiotic conditions. However, under pot culture conditions, Paenibacillus sp. RFNB4 significantly increased plant height and dry biomass production by 42.3% and 29.5%, respectively. Canola plants and rhizosphere soils inoculated with Bacillus sp. RFNB6 exhibited significantly higher nitrogenase activity. In greenhouse experiments, Serratia sp. RFNB18 increased rice plant height by 35.1%, Xanthomonas sp. RFNB24 enhanced biomass production by 84.6%, and rice rhizosphere soils inoculated with Herbaspirillum sp. RFNB26 exhibited the highest nitrogenase activity. Our findings indicate that most of the selected strains possess multiple PGP properties that significantly improve the growth parameters of the two plants when tested under controlled conditions.

Knocking down mitochondrial iron transporter (MIT) reprograms primary and secondary metabolism in rice plants

PubMed Central

Vigani, Gianpiero; Bashir, Khurram; Ishimaru, Yasuhiro; Lehmann, Martin; Casiraghi, Fabio Marco; Nakanishi, Hiromi; Seki, Motoaki; Geigenberger, Peter; Zocchi, Graziano; Nishizawa, Naoko K.

2016-01-01

Iron (Fe) is an essential micronutrient for plant growth and development, and its reduced bioavailability strongly impairs mitochondrial functionality. In this work, the metabolic adjustment in the rice (Oryza sativa) mitochondrial Fe transporter knockdown mutant (mit-2) was analysed. Biochemical characterization of purified mitochondria from rice roots showed alteration in the respiratory chain of mit-2 compared with wild-type (WT) plants. In particular, proteins belonging to the type II alternative NAD(P)H dehydrogenases accumulated strongly in mit-2 plants, indicating that alternative pathways were activated to keep the respiratory chain working. Additionally, large-scale changes in the transcriptome and metabolome were observed in mit-2 rice plants. In particular, a strong alteration (up-/down-regulation) in the expression of genes encoding enzymes of both primary and secondary metabolism was found in mutant plants. This was reflected by changes in the metabolic profiles in both roots and shoots of mit-2 plants. Significant alterations in the levels of amino acids belonging to the aspartic acid-related pathways (aspartic acid, lysine, and threonine in roots, and aspartic acid and ornithine in shoots) were found that are strictly connected to the Krebs cycle. Furthermore, some metabolites (e.g. pyruvic acid, fumaric acid, ornithine, and oligosaccharides of the raffinose family) accumulated only in the shoot of mit-2 plants, indicating possible hypoxic responses. These findings suggest that the induction of local Fe deficiency in the mitochondrial compartment of mit-2 plants differentially affects the transcript as well as the metabolic profiles in root and shoot tissues. PMID:26685186

A Rice cis-Natural Antisense RNA Acts as a Translational Enhancer for Its Cognate mRNA and Contributes to Phosphate Homeostasis and Plant Fitness[C][W

PubMed Central

Jabnoune, Mehdi; Secco, David; Lecampion, Cécile; Robaglia, Christophe; Shu, Qingyao; Poirier, Yves

2013-01-01

cis-natural antisense transcripts (cis-NATs) are widespread in plants and are often associated with downregulation of their associated sense genes. We found that a cis-NAT positively regulates the level of a protein critical for phosphate homeostasis in rice (Oryza sativa). PHOSPHATE1;2 (PHO1;2), a gene involved in phosphate loading into the xylem in rice, and its associated cis-NATPHO1;2 are both controlled by promoters active in the vascular cylinder of roots and leaves. While the PHO1;2 promoter is unresponsive to the plant phosphate status, the cis-NATPHO1;2 promoter is strongly upregulated under phosphate deficiency. Expression of both cis-NATPHO1;2 and the PHO1;2 protein increased in phosphate-deficient plants, while the PHO1;2 mRNA level remained stable. Downregulation of cis-NATPHO1;2 expression by RNA interference resulted in a decrease in PHO1;2 protein, impaired the transfer of phosphate from root to shoot, and decreased seed yield. Constitutive overexpression of NATPHO1;2 in trans led to a strong increase of PHO1;2, even under phosphate-sufficient conditions. Under all conditions, no changes occurred in the level of expression, sequence, or nuclear export of PHO1;2 mRNA. However, expression of cis-NATPHO1;2 was associated with a shift of both PHO1;2 and cis-NATPHO1;2 toward the polysomes. These findings reveal an unexpected role for cis-NATPHO1;2 in promoting PHO1;2 translation and affecting phosphate homeostasis and plant fitness. PMID:24096344

[Effects of intercropping Sedum plumbizincicola in wheat growth season under wheat-rice rotation on the crops growth and their heavy metals uptake from different soil types].

PubMed

Zhao, Bing; Shen, Li-bo; Cheng, Miao-miao; Wang, Song-feng; Wu, Long-hua; Zhou, Shou-biao; Luo, Yong-ming

2011-10-01

A pot experiment with heavy metals- contaminated black soil from Heilongjiang Province, alluvial soil from Henan Province, and paddy soil from Zhejiang Province was conducted to study the effects of intercropping Sedum plumbizincicola in wheat growth season under wheat (Triticum aestivum) - rice (Oryza sativa) rotation on the growth of the crops and their heavy metals uptake, aimed to explore the feasibility of simultaneous grain production and heavy metals-contaminated soil phytoremediation in main food crop production areas of this country. Comparing with monoculture T. aestivum, intercropping S. plumbizincicola increased the soil NaNO3 -extractable Zn and Cd significantly, with the increment of extractable Zn in test paddy soil, alluvial soil, and black soil being 55%, 32% and 110%, and that of extractable Cd in test paddy soil and black soil being 38% and 110%, respectively. The heavy metals concentration in T. aestivum shoots under intercropping S. plumbizincicola was 0.1-0.9 times higher than that under monoculture T. aestivum, but the intercropping had little effects on the rice growth and its heavy metals uptake. Though the Cd concentration in rice grain after S. plumbizincicola planting was still higher than 0.2 mg kg(-1) (the limit of Cd in food standard), it presented a decreasing trend, as compared with that after monoculture T. aestivum. Therefore, intercropping S. plumbizincicola in wheat growth season under wheat-rice rota- tion could benefit the phytoremediation of heavy metals-contaminated soil, and decrease the food-chain risk of rotated rice.

OsABCB14 functions in auxin transport and iron homeostasis in rice (Oryza sativa L.).

PubMed

Xu, Yanxia; Zhang, Saina; Guo, Haipeng; Wang, Suikang; Xu, Ligen; Li, Chuanyou; Qian, Qian; Chen, Fan; Geisler, Markus; Qi, Yanhua; Jiang, De An

2014-07-01

Members of the ATP Binding Cassette B/Multidrug-Resistance/P-glyco-protein (ABCB/MDR/PGP) subfamily were shown to function primarily in Oryza sativa (rice) auxin transport; however, none of the rice ABCB transporters have been functionally characterized. Here, we describe that a knock-down of OsABCB14 confers decreased auxin concentrations and polar auxin transport rates, conferring insensitivity to 2,4-dichlorophenoxyacetic acid (2,4-D) and indole-3-acetic acid (IAA). OsABCB14 displays enhanced specific auxin influx activity in yeast and protoplasts prepared from rice knock-down alleles. OsABCB14 is localized at the plasma membrane, pointing to an important directionality under physiological conditions. osabcb14 mutants were surprisingly found to be insensitive to iron deficiency treatment (-Fe). Their Fe concentration is higher and upregulation of Fe deficiency-responsive genes is lower in osabcb14 mutants than in wild-type rice (Nipponbare, NIP). Taken together, our results strongly support the role of OsABCB14 as an auxin influx transporter involved in Fe homeostasis. The functional characterization of OsABCB14 provides insights in monocot auxin transport and its relationship to Fe nutrition. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

Different Phosphorus Supplies Altered the Accumulations and Quantitative Distributions of Phytic Acid, Zinc, and Iron in Rice (Oryza sativa L.) Grains.

PubMed

Su, Da; Zhou, Lujian; Zhao, Qian; Pan, Gang; Cheng, Fangmin

2018-02-21

Development of rice cultivars with low phytic acid (lpa) is considered as a primary strategy for biofortification of zinc (Zn) and iron (Fe). Here, two rice genotypes (XS110 and its lpa mutant) were used to investigate the effect of P supplies on accumulations and distributions of PA, Zn, and Fe in rice grains by using hydroponics and detached panicle culture system. Results showed that higher P level increased grain PA concentration on dry matter basis (g/kg), but it markedly decreased PA accumulation on per grain basis (mg/grain). Meanwhile, more P supply reduced the amounts and bioavailabilities of Zn and Fe both in milled grains and in brown grains. Comparatively, lpa mutant was more susceptive to exogenous P supply than its wild type. Hence, the appropriate P fertilizer application should be highlighted in order to increase grain microelement (Zn and Fe) contents and improve nutritional quality in rice grains.

Cadmium Accumulation Risk in Vegetables and Rice in Southern China: Insights from Solid-Solution Partitioning and Plant Uptake Factor.

PubMed

Yang, Yang; Wang, Meie; Chen, Weiping; Li, Yanling; Peng, Chi

2017-07-12

Solid-solution partitioning coefficient (K d ) and plant uptake factor (PUF) largely determine the solubility and mobility of soil Cd to food crops. A four-year regional investigation was conducted in contaminated vegetable and paddy fields of southern China to quantify the variability in K d and PUF. The distributions of K d and PUF characterizing transfers of Cd from soil to vegetable and rice are probabilistic in nature. Dynamics in soil pH and soil Zn greatly affected the variations of K d . In addition to soil pH, soil organic matter had a major influence on PUF variations in vegetables. Heavy leaching of soil Mn caused a higher Cd accumulation in rice grain. Dietary ingestion of 85.5% of the locally produced vegetable and rice would have adverse health risks, with rice consumption contributing 97.2% of the risk. A probabilistic risk analysis based on derived transfer function reveals the amorphous Mn oxide content exerts a major influence on Cd accumulation in rice in pH conditions below 5.5. Risk estimation and field experiments show that to limit the Cd concentration in rice grains, soil management strategies should include improving the pH and soil Mn concentration to around 6.0 and 345 mg kg -1 , respectively. Our work illustrates that re-establishing a balance in trace elements in soils' labile pool provides an effective risk-based approach for safer crop practices.

JcDREB2, a Physic Nut AP2/ERF Gene, Alters Plant Growth and Salinity Stress Responses in Transgenic Rice.

PubMed

Tang, Yuehui; Liu, Kun; Zhang, Ju; Li, Xiaoli; Xu, Kedong; Zhang, Yi; Qi, Jing; Yu, Deshui; Wang, Jian; Li, Chengwei

2017-01-01

Transcription factors of the AP2/ERF family play important roles in plant growth, development, and responses to biotic and abiotic stresses. In this study, a physic nut AP2/ERF gene, JcDREB2 , was functionally characterized. Real-time PCR analysis revealed that JcDREB2 was expressed mainly in the leaf and could be induced by abscisic acid but suppressed by gibberellin (GA) and salt. Transient expression of a JcDREB2-YFP fusion protein in Arabidopsis protoplasts cells suggested that JcDREB2 is localized in the nucleus. Rice plants overexpressing JcDREB2 exhibited dwarf and GA-deficient phenotypes with shorter shoots and roots than those of wild-type plants. The dwarfism phenotype could be rescued by the application of exogenous GA 3 . The expression levels of GA biosynthetic genes including OsGA20ox1 , OsGA20ox2 , OsGA20ox4 , OsGA3ox2, OsCPS1 , OsKO2 , and OsKAO were significantly reduced in plants overexpressing JcDREB2 . Overexpression of JcDREB2 in rice increased sensitivity to salt stress. Increases in the expression levels of several salt-tolerance-related genes in response to salt stress were impaired in JcDREB2 -overexpressing plants. These results demonstrated not only that JcDREB2 influences GA metabolism, but also that it can participate in the regulation of the salt stress response in rice.

Electrical properties of Al-, Cu-, Zn- rice husk charcoal junctions

NASA Astrophysics Data System (ADS)

Dahonog, L. A.; Tapia, A. K. G.

2017-04-01

Rice husk in the Philippines is considered as an agricultural waste. In order to utilize the material, one common technique is to carbonize these rice husks to produce charcoal briquettes. These materials are porous in nature exhibiting electrical properties from carbon structures. In this study, rice husk charcoals (RHC) were deposited on different metal substrates (Al, Cu, Zn) via a simple solution casting method. The deposited RHC on metal substrates was observed using Scanning Electron Microscopy (SEM). The films were characterized using two-point probe technique and the I-V curves were plotted. Al-RHC films appear to deviate from an ohmic behaviour while Zn-RHC and Cu-RHC showed diode-like behaviours.

Improving panicle exsertion of rice cytoplasmic male sterile line by combination of artificial microRNA and artificial target mimic.

PubMed

Chen, Hao; Jiang, Shan; Zheng, Jie; Lin, Yongjun

2013-04-01

The adoption of hybrid rice caused the second leap in rice yield after the 'green revolution' and contributes substantially to food security of China and the world. However, almost all cytoplasmic male sterile lines (A lines) as females of hybrid rice have a natural deficiency of 'panicle enclosure', which blocks pollination between the A line and the fertility restorer line as the male (R line) of hybrid rice and decreases seed yield. In hybrid rice seed production, exogenous '920' (the active ingredient is gibberellin A3 ) must be applied to eliminate or alleviate panicle enclosure of the A line; however, this not only increases production cost and pollutes the environment, it also decreases seed quality. In this study, we designed a transgenic approach to improve plant height and panicle exsertion of the A line to facilitate hybrid rice production and maintain the semi-dwarf plant type of the hybrid. This approach comprising two components-artificial microRNA (amiRNA) and artificial target mimicry-can manipulate the differential expression of the endogenous Eui1 gene that is associated with rice internode elongation in the A line and the hybrid. amiRNA is a recently developed gene silencing method with high specificity, while target mimicry is a natural mechanism inhibiting the miRNA function that was also recently characterized. This approach provides a paradigm to tune the expression of endogenous genes to achieve the desired phenotype by combining amiRNA and artificial target mimicry technologies. © 2012 The Authors Plant Biotechnology Journal © 2012 Society for Experimental Biology, Association of Applied Biologists and Blackwell Publishing Ltd.

Biofortification of essential nutritional compounds and trace elements in rice and cassava.

PubMed

Sautter, C; Poletti, S; Zhang, P; Gruissem, W

2006-05-01

Plant biotechnology can make important contributions to food security and nutritional improvement. For example, the development of 'Golden Rice' by Professor Ingo Potrykus was a milestone in the application of gene technology to deliver both increased nutritional qualities and health improvement to wide sections of the human population. Mineral nutrient and protein deficiency as well as food security remain the most important challenges for developing countries. Current projects are addressing these issues in two major staple crops, cassava (Manihot esculenta Crantz) and rice. The tropical root crop cassava is a major source of food for approximately 600 million of the population worldwide. In sub-Saharan Africa >200 million of the population rely on cassava as their major source of dietary energy. The nutritional quality of the cassava root is not sufficient to meet all dietary needs. Rice is the staple food for half the world population, providing approximately 20% of the per capita energy and 13% of the protein for human consumption worldwide. In many developing countries the dietary contributions of rice are substantially greater (29.3% dietary energy and 29.1% dietary protein). The current six most popular 'mega' rice varieties (in terms of popularity and acreage), including Chinese hybrid rice, have an incomplete amino acid profile and contain limited amounts of essential micronutrients. Rice lines with improved Fe contents have been developed using genes that have functions in Fe absorption, translocation and accumulation in the plant, as well as improved Fe bioavailability in the human intestine. Current developments in biotechnology-assisted plant improvement are reviewed and the potential of the technology in addressing human nutrition and health are discussed.

The knockdown of chloroplastic ascorbate peroxidases reveals its regulatory role in the photosynthesis and protection under photo-oxidative stress in rice.

PubMed

Caverzan, Andréia; Bonifacio, Aurenivia; Carvalho, Fabricio E L; Andrade, Claudia M B; Passaia, Gisele; Schünemann, Mariana; Maraschin, Felipe Dos Santos; Martins, Marcio O; Teixeira, Felipe K; Rauber, Rafael; Margis, Rogério; Silveira, Joaquim Albenisio Gomes; Margis-Pinheiro, Márcia

2014-01-01

The inactivation of the chloroplast ascorbate peroxidases (chlAPXs) has been thought to limit the efficiency of the water-water cycle and photo-oxidative protection under stress conditions. In this study, we have generated double knockdown rice (Oryza sativa L.) plants in both OsAPX7 (sAPX) and OsAPX8 (tAPX) genes, which encode chloroplastic APXs (chlAPXs). By employing an integrated approach involving gene expression, proteomics, biochemical and physiological analyses of photosynthesis, we have assessed the role of chlAPXs in the regulation of the protection of the photosystem II (PSII) activity and CO2 assimilation in rice plants exposed to high light (HL) and methyl violagen (MV). The chlAPX knockdown plants were affected more severely than the non-transformed (NT) plants in the activity and structure of PSII and CO2 assimilation in the presence of MV. Although MV induced significant increases in pigment content in the knockdown plants, the increases were apparently not sufficient for protection. Treatment with HL also caused generalized damage in PSII in both types of plants. The knockdown and NT plants exhibited differences in photosynthetic parameters related to efficiency of utilization of light and CO2. The knockdown plants overexpressed other antioxidant enzymes in response to the stresses and increased the GPX activity in the chloroplast-enriched fraction. Our data suggest that a partial deficiency of chlAPX expression modulate the PSII activity and integrity, reflecting the overall photosynthesis when rice plants are subjected to acute oxidative stress. However, under normal growth conditions, the knockdown plants exhibit normal phenotype, biochemical and physiological performance. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Gibberellins producing Bacillus methylotrophicus KE2 supports plant growth and enhances nutritional metabolites and food values of lettuce.

PubMed

Radhakrishnan, Ramalingam; Lee, In-Jung

2016-12-01

The nutritional quality of green leafy vegetables can be enhanced by application of plant beneficial micro-organisms. The present study was aimed to increase the food values of lettuce leaves by bacterial treatment. We isolated bacterial strain KE2 from Kimchi food and identified as Bacillus methylotrophicus by phylogenetic analysis. The beneficial effect of B. methylotrophicus KE2 on plants was confirmed by increasing the percentage of seed germination of Lactuca sativa L., Cucumis melo L., Glycine max L. and Brassica juncea L. It might be the secretion of array of gibberellins (GA 1 , GA 3 , GA 7 , GA 8 , GA 9 , GA 12 , GA 19 , GA 20 , GA 24 , GA 34 and GA 53 ) and indole-acetic acid from B. methylotrophicus KE2. The mechanism of plant growth promotion via their secreted metabolites was confirmed by a significant increase of GA deficient mutant rice plant growth. Moreover, the bacterial association was favor to enhance shoot length, shoot fresh weight and leaf width of lettuce. The higher concentration of protein, amino acids (Asp, Thr, Ser, Glu, Gly, Ala, Leu, Tyr and His), gama-aminobutric acid and fructose was found in bacterial culture (KE2) applied plants. The macro and micro minerals such as K, Mg, Na, P, Fe, Zn and N were also detected as significantly higher quantities in bacteria treated plants than untreated control plants. In addition, the carotenoids and chlorophyll a were also increased in lettuce at bacterial inoculation. The results of this study suggest that B. methylotrophicus KE2 application to soil helps to increase the plant growth and food values of lettuce. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

A market basket survey of As, Zn and Se in rice imports in Qatar: health implications.

PubMed

Rowell, Candace; Kuiper, Nora; Al-Saad, Khalid; Nriagu, Jerome; Shomar, Basem

2014-08-01

Qatar is dependent on importation of rice, its staple dish, and is therefore susceptible to compromises of food quality in the global market. This market basket study assesses potential health risks of As exposure from rice consumption in Qatar and examines its contribution to the recommended nutritional intakes (RNI) for Zn and Se. Fifty-six rice types and 12 products sold in Qatar were analyzed by ICP/MS. Mean concentrations and ranges were 96.2±54.1μg/kg (9.76-258μg/kg) for As; 12.5±5.35mg/kg (2.79-29.9mg/kg) for Zn and 103±113μg/kg (<5.94-422μg/kg) for Se. Calculated risk quotient shows rice consumption in Qatar is not a significant route of As exposure but can contribute up to 100% and 50% of the RNI for Se and Zn, respectively. Results indicate that children in Qatar may be at elevated risk of arsenic exposure from rice-based infant cereals but more data is needed to obtain a definitive assessment. Copyright © 2014 Elsevier Ltd. All rights reserved.

LPCAT1 controls phosphate homeostasis in a zinc-dependent manner

PubMed Central

Kisko, Mushtak; Bouain, Nadia; Safi, Alaeddine; Medici, Anna; Akkers, Robert C; Secco, David; Fouret, Gilles; Krouk, Gabriel; Aarts, Mark GM; Busch, Wolfgang

2018-01-01

All living organisms require a variety of essential elements for their basic biological functions. While the homeostasis of nutrients is highly intertwined, the molecular and genetic mechanisms of these dependencies remain poorly understood. Here, we report a discovery of a molecular pathway that controls phosphate (Pi) accumulation in plants under Zn deficiency. Using genome-wide association studies, we first identified allelic variation of the Lyso-PhosphatidylCholine (PC) AcylTransferase 1 (LPCAT1) gene as the key determinant of shoot Pi accumulation under Zn deficiency. We then show that regulatory variation at the LPCAT1 locus contributes significantly to this natural variation and we further demonstrate that the regulation of LPCAT1 expression involves bZIP23 TF, for which we identified a new binding site sequence. Finally, we show that in Zn deficient conditions loss of function of LPCAT1 increases the phospholipid Lyso-PhosphatidylCholine/PhosphatidylCholine ratio, the expression of the Pi transporter PHT1;1, and that this leads to shoot Pi accumulation. PMID:29453864

Effects of alkaline and bioorganic amendments on cadmium, lead, zinc, and nutrient accumulation in brown rice and grain yield in acidic paddy fields contaminated with a mixture of heavy metals.

PubMed

He, Huaidong; Tam, Nora F Y; Yao, Aijun; Qiu, Rongliang; Li, Wai Chin; Ye, Zhihong

2016-12-01

Paddy soils and rice (Oryza sativa L.) contaminated by mixed heavy metals have given rise to great concern. Field experiments were conducted over two cultivation seasons to study the effects of steel slag (SS), fly ash (FA), limestone (LS), bioorganic fertilizer (BF), and the combination of SS and BF (SSBF) on rice grain yield, Cd, Pb, and Zn and nutrient accumulation in brown rice, bioavailability of Cd, Pb, and Zn in soil as well as soil properties (pH and catalase), at two acidic paddy fields contaminated with mixed heavy metals (Cd, Pb, and Zn). Compared to the controls, SS, LS, and SSBF at both low and high additions significantly elevated soil pH over both cultivation seasons. The high treatments of SS and SSBF markedly increased grain yields, the accumulation of P and Ca in brown rice and soil catalase activities in the first cultivation season. The most striking result was from SS application (4.0 t ha -1 ) that consistently and significantly reduced the soil bioavailability of Cd, Pb, and Zn by 38.5-91.2 % and the concentrations of Cd and Pb in brown rice by 20.9-50.9 % in the two soils over both cultivation seasons. LS addition (4.0 t ha -1 ) also markedly reduced the bioavailable Cd, Pb, and Zn in soil and the Cd concentrations in brown rice. BF remobilized soil Cd and Pb leading to more accumulation of these metals in brown rice. The results showed that steel slag was most effective in the remediation of acidic paddy soils contaminated with mixed heavy metals.

Nutritionally enhanced rice to combat malnutrition disorders of the poor.

PubMed

Potrykus, Ingo

2003-06-01

Major deficiency disorders, including vitamin A deficiency, are especially common in countries in which rice is the staple food. In response to the devastating effects of vitamin A deficiency, which may include blindness and, even death, "Golden Rice" has been developed to deliver this nutrient to those populations who need it most. The case of Golden Rice is used to demonstrate the challenges of radical GMO opposition, consumer acceptance, and regulation of biotechnology-derived foods.

Examining Two Sets of Introgression Lines in Rice (Oryza sativa L.) Reveals Favorable Alleles that Improve Grain Zn and Fe Concentrations

PubMed Central

Hu, Xia; Cheng, Li-Rui; Xu, Jian-Long; Shi, Yu-Min; Li, Zhi-Kang

2015-01-01

In the modern world, the grain mineral concentration (GMC) in rice (Oryza sativa L.) not only includes important micronutrient elements such as iron (Fe) and zinc (Zn), but it also includes toxic heavy metal elements, especially cadmium (Cd) and lead (Pb). To date, the genetic mechanisms underlying the regulation of GMC, especially the genetic background and G × E effects of GMC, remain largely unknown. In this study, we adopted two sets of backcross introgression lines (BILs) derived from IR75862 (a Zn-dense rice variety) as the donor parent and two elite indica varieties, Ce258 and Zhongguangxiang1, as recurrent parents to detect QTL affecting GMC traits including Fe, Zn, Cd and Pb concentrations in two environments. We detected a total of 22 loci responsible for GMC traits, which are distributed on all 12 rice chromosomes except 5, 9 and 10. Six genetic overlap (GO) regions affecting multiple elements were found, in which most donor alleles had synergistic effects on GMC. Some toxic heavy metal-independent loci (such as qFe1, qFe2 and qZn12) and some regions that have opposite genetic effects on micronutrient (Fe and Zn) and heavy metal element (Pb) concentrations (such as GO-IV) may be useful for marker-assisted biofortification breeding in rice. We discuss three important points affecting biofortification breeding efforts in rice, including correlations between different GMC traits, the genetic background effect and the G × E effect. PMID:26161553

Knocking down mitochondrial iron transporter (MIT) reprograms primary and secondary metabolism in rice plants.

PubMed

Vigani, Gianpiero; Bashir, Khurram; Ishimaru, Yasuhiro; Lehmann, Martin; Casiraghi, Fabio Marco; Nakanishi, Hiromi; Seki, Motoaki; Geigenberger, Peter; Zocchi, Graziano; Nishizawa, Naoko K

2016-03-01

Iron (Fe) is an essential micronutrient for plant growth and development, and its reduced bioavailability strongly impairs mitochondrial functionality. In this work, the metabolic adjustment in the rice (Oryza sativa) mitochondrial Fe transporter knockdown mutant (mit-2) was analysed. Biochemical characterization of purified mitochondria from rice roots showed alteration in the respiratory chain of mit-2 compared with wild-type (WT) plants. In particular, proteins belonging to the type II alternative NAD(P)H dehydrogenases accumulated strongly in mit-2 plants, indicating that alternative pathways were activated to keep the respiratory chain working. Additionally, large-scale changes in the transcriptome and metabolome were observed in mit-2 rice plants. In particular, a strong alteration (up-/down-regulation) in the expression of genes encoding enzymes of both primary and secondary metabolism was found in mutant plants. This was reflected by changes in the metabolic profiles in both roots and shoots of mit-2 plants. Significant alterations in the levels of amino acids belonging to the aspartic acid-related pathways (aspartic acid, lysine, and threonine in roots, and aspartic acid and ornithine in shoots) were found that are strictly connected to the Krebs cycle. Furthermore, some metabolites (e.g. pyruvic acid, fumaric acid, ornithine, and oligosaccharides of the raffinose family) accumulated only in the shoot of mit-2 plants, indicating possible hypoxic responses. These findings suggest that the induction of local Fe deficiency in the mitochondrial compartment of mit-2 plants differentially affects the transcript as well as the metabolic profiles in root and shoot tissues. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Green manure addition to soil increases grain zinc concentration in bread wheat.

PubMed

Aghili, Forough; Gamper, Hannes A; Eikenberg, Jost; Khoshgoftarmanesh, Amir H; Afyuni, Majid; Schulin, Rainer; Jansa, Jan; Frossard, Emmanuel

2014-01-01

Zinc (Zn) deficiency is a major problem for many people living on wheat-based diets. Here, we explored whether addition of green manure of red clover and sunflower to a calcareous soil or inoculating a non-indigenous arbuscular mycorrhizal fungal (AMF) strain may increase grain Zn concentration in bread wheat. For this purpose we performed a multifactorial pot experiment, in which the effects of two green manures (red clover, sunflower), ZnSO4 application, soil γ-irradiation (elimination of naturally occurring AMF), and AMF inoculation were tested. Both green manures were labeled with 65Zn radiotracer to record the Zn recoveries in the aboveground plant biomass. Application of ZnSO4 fertilizer increased grain Zn concentration from 20 to 39 mg Zn kg-1 and sole addition of green manure of sunflower to soil raised grain Zn concentration to 31 mg Zn kg-1. Adding the two together to soil increased grain Zn concentration even further to 54 mg Zn kg-1. Mixing green manure of sunflower to soil mobilized additional 48 µg Zn (kg soil)-1 for transfer to the aboveground plant biomass, compared to the total of 132 µg Zn (kg soil)-1 taken up from plain soil when neither green manure nor ZnSO4 were applied. Green manure amendments to soil also raised the DTPA-extractable Zn in soil. Inoculating a non-indigenous AMF did not increase plant Zn uptake. The study thus showed that organic matter amendments to soil can contribute to a better utilization of naturally stocked soil micronutrients, and thereby reduce any need for major external inputs.

Phosphorus reduces the zinc concentration in cereals pot-grown on calcareous Vertisols from southern Spain.

PubMed

Sánchez-Rodríguez, Antonio Rafael; Del Campillo, María Carmen; Torrent, José

2017-08-01

Zinc deficiency, a major problem in crops grown on soils low in available Zn, is even more important in phosphorus-rich soils. This work aimed to elucidate the effects of soil P and Zn levels, and of fertilizer application, on yield and Zn concentration in cereal grains. Wheat and barley were successively pot-grown on 20 calcareous Vertisols low in available Zn and ranging widely in available P. Grain yield in the plants grown on the native soils was positively correlated with Olsen P but not with diethylenetriaminepentaacetic acid (DTPA)-extractable Zn except for wheat on P-rich soils. Grain Zn concentration was negatively correlated with Olsen P. Grain Zn uptake differed little among soils. Application of P to the soils increased grain yield insignificantly and P concentration significantly; however, it reduced grain Zn concentration (particularly at low Olsen P values). Applying Zn alone only increased grain Zn concentration, whereas applying P and Zn in combination increased yield and grain Zn concentration at low and high Olsen P values, respectively. Applying P alone to plants grown on calcareous Vertisols low in available P and Zn may in practice reduce grain Zn concentrations while not increasing grain yield significantly. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Elemental and isotopic behaviour of Zn in Deccan basalt weathering profiles: Chemical weathering from bedrock to laterite and links to Zn deficiency in tropical soils.

PubMed

Suhr, Nils; Schoenberg, Ronny; Chew, David; Rosca, Carolina; Widdowson, Mike; Kamber, Balz S

2018-04-01

Zinc (Zn) is a micronutrient for organisms and essential for plant growth, therefore knowledge of its elemental cycling in the surface environment is important regarding wider aspects of human nutrition and health. To explore the nature of Zn cycling, we compared its weathering behaviour in a sub-recent regolith versus an ancient laterite profile of the Deccan Traps, India - an area of known soil Zn deficiency. We demonstrate that progressive breakdown of primary minerals and the associated formation of phyllosilicates and iron oxides leads to a depletion in Zn, ultimately resulting in a loss of 80% in lateritic residues. This residue is mainly composed of resistant iron oxides and hydroxides ultimately delivering insufficient amounts of bio-available Zn. Moreover, (sub)-tropical weathering in regions experiencing extended tectonic quiescence (e.g., cratons) further enhance the development of old and deep soil profiles that become deficient in Zn. This situation is clearly revealed by the spatial correlation of the global distribution of laterites, cratons (Africa, India, South America and Australia) and known regions of Zn deficient soils that result in health problems for humans whose diet is derived from such land. We also investigate whether this elemental depletion of Zn is accompanied by isotope fractionation. In the saprolitic horizons of both weathering profiles, compositions of δ 66 Zn JMC-Lyon lie within the "crustal average" of +0.27±0.07‰ δ 66 Zn JMC-Lyon . By contrast, soil horizons enriched in secondary oxides show lighter isotope compositions. The isotopic signature of Zn (Δ 66 Zn sample-protolith up to ~ -0.65‰) during the formation of the ferruginous-lateritic weathering profile likely resulted from a combination of biotically- and kinetically-controlled sorption reactions on Fe-oxyhydroxides. Our findings suggest that oxide rich soil types/horizons in (sub)-tropical regions likely exert a control on riverine Zn isotope compositions such that these become heavier than the crustal average. This isotopic behaviour invites a broader study of global soils to test whether light isotope composition alone could serve as an indicator for reduced bioavailability of Zn. Copyright © 2017 Elsevier B.V. All rights reserved.

Zn uptake behavior of rice genotypes and its implication on grain Zn biofortification

PubMed Central

Johnson-Beebout, Sarah E.; Goloran, Johnvie Bayang; Rubianes, Francis H. C.; Jacob, Jack D. C.; Castillo, Oliver B.

2016-01-01

Understanding Zn uptake dynamics is critical to rice grain Zn biofortification. Here we examined soil Zn availability and Zn uptake pathways as affected by genotype (high-grain Zn varieties IR69428 and IR68144), Zn fertilization and water management in two pot experiments. Results showed significant interactions (P < 0.05) between genotypes and Zn fertilization on DTPA (diethylenetriaminepentaacetic acid)-extractable soil Zn from early tillering to flowering. DTPA-extractable Zn in soils grown with IR69428 was positively correlated with stem (r = 0.78, P < 0.01), flagleaf (r = 0.60, P < 0.01) and grain (r = 0.67, P < 0.01) Zn concentrations, suggesting improved soil Zn availability and continued soil Zn uptake by IR69428 even at maturity. Conversely for IR68144, DTPA-extractable Zn was positively correlated only with leaf Zn uptake (r = 0.60, P < 0.01) at active tillering, indicating dependence on remobilization for grain Zn loading. Furthermore, the highest grain Zn concentration (P < 0.05) was produced by a combination of IR69428 and Zn fertilization applied at panicle initiation (38.5 μg g−1) compared with other treatments (P < 0.05). The results highlight that Zn uptake behavior of a rice genotype determines the fate of Zn from the soil to the grain. This has implications on overcoming Zn translocation barriers between vegetative parts and grains, and achieving grain Zn biofortification targets (30.0 μg g−1). PMID:27910900

Zinc deficiency in field-grown pecan trees: changes in leaf nutrient concentrations and structure.

PubMed

Ojeda-Barrios, Dámaris; Abadía, Javier; Lombardini, Leonardo; Abadía, Anunciación; Vázquez, Saúl

2012-06-01

Zinc (Zn) deficiency is a typical nutritional disorder in pecan trees [Carya illinoinensis (Wangenh.) C. Koch] grown under field conditions in calcareous soils in North America, including northern Mexico and south-western United States. The aim of this study was to assess the morphological and nutritional changes in pecan leaves affected by Zn deficiency as well as the Zn distribution within leaves. Zinc deficiency led to decreases in leaf chlorophyll concentrations, leaf area and trunk cross-sectional area. Zinc deficiency increased significantly the leaf concentrations of K and Ca, and decreased the leaf concentrations of Zn, Fe, Mn and Cu. All nutrient values found in Zn-deficient leaves were within the sufficiency ranges, with the only exception of Zn, which was approximately 44, 11 and 9 µg g(-1) dry weight in Zn-sufficient, moderately and markedly Zn-deficient leaves, respectively. Zinc deficiency led to decreases in leaf thickness, mainly due to a reduction in the thickness of the palisade parenchyma, as well as to increases in stomatal density and size. The localisation of Zn was determined using the fluorophore Zinpyr-1 and ratio-imaging technique. Zinc was mainly localised in the palisade mesophyll area in Zn-sufficient leaves, whereas no signal could be obtained in Zn-deficient leaves. The effects of Zn deficiency on the leaf characteristics of pecan trees include not only decreases in leaf chlorophyll and Zn concentrations, but also a reduction in the thickness of the palisade parenchyma, an increase in stomatal density and pore size and the practical disappearance of Zn leaf pools. These characteristics must be taken into account to design strategies to correct Zn deficiency in pecan tree in the field. Copyright © 2012 Society of Chemical Industry.

SHOEBOX Modulates Root Meristem Size in Rice through Dose-Dependent Effects of Gibberellins on Cell Elongation and Proliferation

PubMed Central

Li, Jintao; Zhao, Yu; Chu, Huangwei; Wang, Likai; Fu, Yanru; Liu, Ping; Upadhyaya, Narayana; Chen, Chunli; Mou, Tongmin; Feng, Yuqi; Kumar, Prakash; Xu, Jian

2015-01-01

Little is known about how the size of meristem cells is regulated and whether it participates in the control of meristem size in plants. Here, we report our findings on shoebox (shb), a mild gibberellin (GA) deficient rice mutant that has a short root meristem size. Quantitative analysis of cortical cell length and number indicates that shb has shorter, rather than fewer, cells in the root meristem until around the fifth day after sowing, from which the number of cortical cells is also reduced. These defects can be either corrected by exogenous application of bioactive GA or induced in wild-type roots by a dose-dependent inhibitory effect of paclobutrazol on GA biosynthesis, suggesting that GA deficiency is the primary cause of shb mutant phenotypes. SHB encodes an AP2/ERF transcription factor that directly activates transcription of the GA biosynthesis gene KS1. Thus, root meristem size in rice is modulated by SHB-mediated GA biosynthesis that regulates the elongation and proliferation of meristem cells in a developmental stage-specific manner. PMID:26275148

SHOEBOX Modulates Root Meristem Size in Rice through Dose-Dependent Effects of Gibberellins on Cell Elongation and Proliferation.

PubMed

Li, Jintao; Zhao, Yu; Chu, Huangwei; Wang, Likai; Fu, Yanru; Liu, Ping; Upadhyaya, Narayana; Chen, Chunli; Mou, Tongmin; Feng, Yuqi; Kumar, Prakash; Xu, Jian

2015-08-01

Little is known about how the size of meristem cells is regulated and whether it participates in the control of meristem size in plants. Here, we report our findings on shoebox (shb), a mild gibberellin (GA) deficient rice mutant that has a short root meristem size. Quantitative analysis of cortical cell length and number indicates that shb has shorter, rather than fewer, cells in the root meristem until around the fifth day after sowing, from which the number of cortical cells is also reduced. These defects can be either corrected by exogenous application of bioactive GA or induced in wild-type roots by a dose-dependent inhibitory effect of paclobutrazol on GA biosynthesis, suggesting that GA deficiency is the primary cause of shb mutant phenotypes. SHB encodes an AP2/ERF transcription factor that directly activates transcription of the GA biosynthesis gene KS1. Thus, root meristem size in rice is modulated by SHB-mediated GA biosynthesis that regulates the elongation and proliferation of meristem cells in a developmental stage-specific manner.

Assessment of phytoavailability of heavy metals in tropical soils by modified Neubauer method (organic extractor).

NASA Astrophysics Data System (ADS)

Mellis, E. V.; Rodella, A. A.; Levy, C. C. B.

2012-04-01

Nowadays authors discuss the use of metal content phytoavailable in replacement of the total content to establish regulatory limits for metals in soils. However, there is still no patterning in the method to be used to estimate the phytoavailability of metals present in soils and is usually used extraction solutions such as: DTPA, Mehlich 3 and HCl. Although the use of these solutions is an alternative, these extractors have large efficacy variation according to the metal concentration in soil, soil type, the presence of other chemical species, plant species and the metal in question. An alternative would be to use biological methods, with the use of plants to assess the availability of metals that could be used in routine laboratories. The aim of this study was to determine the phytoavailability of Cd, Cu, Ni and Zn by the method of Neubauer, correlating levels of soluble metals determined by DTPA in soil treated with sewage sludge, and its absorption by rice plants. In this experiment it was used the modification proposed by Catani and Bergamin (1960) of the original procedure established by Neubauer and Schneider (1923). Studies were conducted on samples of a Rhodic soil (clayey), obtained in experiments in which sewage sludge was applied in corn, located in the Experimental Field of Embrapa Environment, Jaguariúna (SP), latitude 22o41 'south, longitude W. 47th Gr and altitude of 570 m. The sewage sludge were generated in the Stations of Sewage Treatment of Barueri (State of São Paulo, Brazil), which treats domestic and industrial sludge (Sludge Barueri - SB) and Stations of Sewage Treatment of Franca (State of São Paulo, Brazil), which deals mainly with domestic sludge (Sludge Franca - SF). The applications of sewage sludge were made from 1999 for five consecutive years and on average, it was applied the following amounts of sludge per year: 0, 5, 10, 20 and 40 t ha-1. It was evaluated the dry matter production, nutrient concentrations in the plant and the quantities of Cu, Ni and Zn extracted by plants. As a possible term of comparison with the contents of heavy metals in leaf tissue of rice, it might be considered to phytotoxic levels in mg kg-1: 30 to 20 for Cu, 50 to 100 for Ni and 500 to 1500 for Zn. The concentration of Cu extracted by rice plants had significant influence only for the amount of sludge factor regardless of its source. The elements Ni and Zn showed significant response to both doses of sludge used in the field, and for the type of sludge used, with the greatest accumulation of these metals in the samples treated with domestic and industrial sewage (Sludge Barueri - SB). Based on these results it can be concluded that the modified Neubauer method can be an efficient method for the determination of phytoavailable metals in soils, requiring further studies to confirm such efficiency.

Higher concentrations of nanoscale zero-valent iron (nZVI) in soil induced rice chlorosis due to inhibited active iron transportation.

PubMed

Wang, Jie; Fang, Zhanqiang; Cheng, Wen; Yan, Xiaomin; Tsang, Pokeung Eric; Zhao, Dongye

2016-03-01

In this study, the effects of concentrations 0, 100, 250, 500, 750 and 1000 mg kg(-1) of nanoscale zero-valent iron (nZVI) on germination, seedlings growth, physiology and toxicity mechanisms were investigated. The results showed that nZVI had no effect on germination, but inhibited the rice seedlings growth in higher concentrations (>500 mg kg(-1) nZVI). The highest suppression rate of the length of roots and shoots reached 46.9% and 57.5%, respectively. The 1000mg kg(-1) nZVI caused the highest suppression rates for chlorophyll and carotenoids, at 91.6% and 85.2%, respectively. In addition, the activity of antioxidant enzymes was altered by the translocation of nanoparticles and changes in active iron content. Visible symptoms of iron deficiency were observed at higher concentrations, at which the active iron content decreased 61.02% in the shoots, but the active iron content not decreased in roots. Interestingly, the total and available amounts of iron in the soil were not less than those in the control. Therefore, the plants iron deficiency was not caused by (i) deficiency of available iron in the soil and (ii) restraint of the absorption that plant takes in the available iron, while induced by (ⅲ) the transport of active iron from the root to the shoot was blocked. The cortex tissues were seriously damaged by nZVI which was transported from soil to the root, these were proved by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). This current study shows that the mechanism of iron deficiency in rice seedling was due to transport of active iron from the root to the shoot blocked, which was caused by the uptake of nZVI. Copyright © 2016 Elsevier Ltd. All rights reserved.

Azospirillum brasilense and Azospirillum lipoferum Hydrolyze Conjugates of GA20 and Metabolize the Resultant Aglycones to GA1 in Seedlings of Rice Dwarf Mutants1

PubMed Central

Cassán, Fabricio; Bottini, Rubén; Schneider, Gernot; Piccoli, Patricia

2001-01-01

Azospirillum species are plant growth-promotive bacteria whose beneficial effects have been postulated to be partially due to production of phytohormones, including gibberellins (GAs). In this work, Azospirillum brasilense strain Cd and Azospirillum lipoferum strain USA 5b promoted sheath elongation growth of two single gene GA-deficient dwarf rice (Oryza sativa) mutants, dy and dx, when the inoculated seedlings were supplied with [17,17-2H2]GA20-glucosyl ester or [17,17- 2H2]GA20-glucosyl ether. Results of capillary gas chromatography-mass spectrometry analysis show that this growth was due primarily to release of the aglycone [17,17-2H2]GA20 and its subsequent 3β-hydroxylation to [17,17-2H2]GA1 by the microorganism for the dy mutant, and by both the rice plant and microorganism for the dx mutant. PMID:11299384

Exogenously applied zinc and copper mitigate salinity effect in maize (Zea mays L.) by improving key physiological and biochemical attributes.

PubMed

Iqbal, Muhammad Naveed; Rasheed, Rizwan; Ashraf, Muhammad Yasin; Ashraf, Muhammad Arslan; Hussain, Iqbal

2018-06-07

Zinc or copper deficiency and salinity are known soil problems and often occur simultaneously in agriculture soils. Plants undergo various changes in physiological and biochemical processes to respond to high salt in the growing medium. There is lack of information on the relation of exogenous application of Zn and Cu with important salinity tolerance mechanisms in plants. Therefore, the present study was conducted to determine the effect of foliar Zn and Cu on two maize cultivars (salt-tolerant cv. Yousafwala Hybrid and salt-sensitive cv. Hybrid 1898). Salinity caused a significant reduction in water and turgor potentials, stomatal conductance, and transpiration and photosynthetic rate, while increase in glycine betaine, proline, total soluble sugars, and total free amino acids was evident in plants under saline regimes. Furthermore, there was significant decline in P, N, Ca, K, Mn, Fe, Zn, and Cu and increase in Na and Cl contents in plants fed with NaCl salinity. Nitrate reductase activity was lower in salt-stressed plants. However, foliar application of Zn and Cu circumvented salinity effect on water relations, photosynthesis, and nutrition and this was attributed to the better antioxidant system and enhanced accumulation of glycine betaine, proline, total free amino acids, and sugars. The results of the present study suggested that Zn application was superior to Cu for mediating plant defense responses under salinity.

Overexpression of Thiamin Biosynthesis Genes in Rice Increases Leaf and Unpolished Grain Thiamin Content But Not Resistance to Xanthomonas oryzae pv. oryzae

PubMed Central

Dong, Wei; Thomas, Nicholas; Ronald, Pamela C.; Goyer, Aymeric

2016-01-01

Thiamin diphosphate (ThDP), also known as vitamin B1, serves as an enzymatic cofactor in glucose metabolism, the Krebs cycle, and branched-chain amino acid biosynthesis in all living organisms. Unlike plants and microorganisms, humans are not able to synthesize ThDP de novo and must obtain it from their diet. Staple crops such as rice are poor sources of thiamin. Hence, populations that mainly consume rice commonly suffer thiamin deficiency. In addition to thiamin’s nutritional function, studies in rice have shown that some thiamin biosynthesis genes are involved in resistance to Xanthomonas oryzae, which causes a serious disease in rice fields. This study shows that overexpression of two thiamin biosynthesis genes, 4-methyl-5-β-hydroxyethylthiazole phosphate synthase and 4-amino-2-methyl-5-hydroxymethylpyrimidine phosphate synthase, involved in the first steps of the thiazole and pyrimidine synthesis branches, respectively, increased thiamin content up to fivefold in unpolished seeds that retain the bran. However, thiamin levels in polished seeds with removed bran were similar to those found in polished control seeds. Plants with higher accumulation of thiamin did not show enhanced resistance to X. oryzae. These results indicate that stacking of two traits can enhance thiamin accumulation in rice unpolished grain. We discuss potential roadblocks that prevent thiamin accumulation in the endosperm. PMID:27242822

Deficiency of Starch Synthase IIIa and IVb Alters Starch Granule Morphology from Polyhedral to Spherical in Rice Endosperm1

PubMed Central

Toyosawa, Yoshiko; Kawagoe, Yasushi; Matsushima, Ryo; Ogawa, Masahiro; Fukuda, Masako; Kumamaru, Toshihiro; Okazaki, Yozo; Kusano, Miyako; Saito, Kazuki; Toyooka, Kiminori; Sato, Mayuko; Ai, Yongfeng; Fujita, Naoko

2016-01-01

Starch granule morphology differs markedly among plant species. However, the mechanisms controlling starch granule morphology have not been elucidated. Rice (Oryza sativa) endosperm produces characteristic compound-type granules containing dozens of polyhedral starch granules within an amyloplast. Some other cereal species produce simple-type granules, in which only one starch granule is present per amyloplast. A double mutant rice deficient in the starch synthase (SS) genes SSIIIa and SSIVb (ss3a ss4b) produced spherical starch granules, whereas the parental single mutants produced polyhedral starch granules similar to the wild type. The ss3a ss4b amyloplasts contained compound-type starch granules during early developmental stages, and spherical granules were separated from each other during subsequent amyloplast development and seed dehydration. Analysis of glucan chain length distribution identified overlapping roles for SSIIIa and SSIVb in amylopectin chain synthesis, with a degree of polymerization of 42 or greater. Confocal fluorescence microscopy and immunoelectron microscopy of wild-type developing rice seeds revealed that the majority of SSIVb was localized between starch granules. Therefore, we propose that SSIIIa and SSIVb have crucial roles in determining starch granule morphology and in maintaining the amyloplast envelope structure. We present a model of spherical starch granule production. PMID:26747287

Increasing CO2 differentially affects essential and non-essential amino acid concentration of rice grains grown in cadmium-contaminated soils.

PubMed

Wu, Huibin; Song, Zhengguo; Wang, Xiao; Liu, Zhongqi; Tang, Shirong

2016-09-01

Environmental pollution by both ambient CO2 and heavy metals has been steadily increasing, but we do not know how fluctuating CO2 concentrations influence plant nutrients under high Cd pollution, especially in crops. Here, we studied the effects of elevated CO2 and Cd accumulation on proteins and amino acids in rice under Cd stress. In this pot experiment, we analyzed the amino-acid profile of 20 rice cultivars that accumulate Cd differently; the plants were grown in Cd-containing soils under ambient conditions and elevated CO2 levels. We found that although Cd concentrations appeared to be higher in most cultivars under elevated CO2 than under ambient CO2, the effect was significant only in seven cultivars. Combined exposure to Cd and elevated CO2 strongly decreased rice protein and amino acid profiles, including essential and non-essential amino acids. Under elevated CO2, the ratios of specific amino acids were either higher or lower than the optimal ratios provided by FAO/WHO, suggesting that CO2 may flatten the overall amino-acid profile, leading to an excess in some amino acids and deficiencies in others when the rice is consumed. Thus, Cd-tainted rice limits the concentration of essential amino acids in rice-based diets, and the combination with elevated CO2 further exacerbates the problem. Copyright © 2016 Elsevier Ltd. All rights reserved.

TALEN-Based Mutagenesis of Lipoxygenase LOX3 Enhances the Storage Tolerance of Rice (Oryza sativa) Seeds.

PubMed

Ma, Lei; Zhu, Fugui; Li, Zhenwei; Zhang, Jianfu; Li, Xin; Dong, Jiangli; Wang, Tao

2015-01-01

The deterioration of rice grain reduces the quality of rice, resulting in serious economic losses for farmers. Lipoxygenases (LOXs) catalyze the dioxygenation of polyunsaturated fatty acids with at least one cis,cis-1,4-pentadiene to form hydroperoxide, which is a major factor influencing seed longevity and viability. Recently, genome editing, an essential tool employed in reverse genetics, has been used experimentally to investigate basic plant biology or to modify crop plants for the improvement of important agricultural traits. In this study, we performed targeted mutagenesis in rice using transcription activator-like effector nucleases (TALENs) to improve seed storability. A modified ligation-independent cloning method (LIC) was employed to allow for the quick and efficient directional insertion of TALEN monomer modules into destination vectors used in plants. We demonstrated the feasibility and flexibility of the technology by developing a set of modular vectors for genome editing. After construction and validation, the TALEN pairs were used to create stable transgenic rice lines via Agrobacterium-mediated transformation. One heterozygous mutant (4%) was recovered from 25 transgenic NPTII-resistant lines, and the mutation was transmitted to the next generation. Further molecular and protein level experiments verified LOX3 deficiency and demonstrated the improvement of seed storability. Our work provides a flexible genome editing tool for improving important agronomic traits, as well as direct evidence that Lox3 has only a limited impact on seed longevity.

TALEN-Based Mutagenesis of Lipoxygenase LOX3 Enhances the Storage Tolerance of Rice (Oryza sativa) Seeds

PubMed Central

Li, Zhenwei; Zhang, Jianfu; Li, Xin; Dong, Jiangli; Wang, Tao

2015-01-01

The deterioration of rice grain reduces the quality of rice, resulting in serious economic losses for farmers. Lipoxygenases (LOXs) catalyze the dioxygenation of polyunsaturated fatty acids with at least one cis,cis-1,4-pentadiene to form hydroperoxide, which is a major factor influencing seed longevity and viability. Recently, genome editing, an essential tool employed in reverse genetics, has been used experimentally to investigate basic plant biology or to modify crop plants for the improvement of important agricultural traits. In this study, we performed targeted mutagenesis in rice using transcription activator-like effector nucleases (TALENs) to improve seed storability. A modified ligation-independent cloning method (LIC) was employed to allow for the quick and efficient directional insertion of TALEN monomer modules into destination vectors used in plants. We demonstrated the feasibility and flexibility of the technology by developing a set of modular vectors for genome editing. After construction and validation, the TALEN pairs were used to create stable transgenic rice lines via Agrobacterium-mediated transformation. One heterozygous mutant (4%) was recovered from 25 transgenic NPTII-resistant lines, and the mutation was transmitted to the next generation. Further molecular and protein level experiments verified LOX3 deficiency and demonstrated the improvement of seed storability. Our work provides a flexible genome editing tool for improving important agronomic traits, as well as direct evidence that Lox3 has only a limited impact on seed longevity. PMID:26641666

OsGA2ox5, a Gibberellin Metabolism Enzyme, Is Involved in Plant Growth, the Root Gravity Response and Salt Stress

PubMed Central

Shan, Chi; Mei, Zhiling; Duan, Jianli; Chen, Haiying; Feng, Huafeng; Cai, Weiming

2014-01-01

Gibberellin (GA) 2-oxidases play an important role in the GA catabolic pathway through 2β-hydroxylation. There are two classes of GA2oxs, i.e., a larger class of C19-GA2oxs and a smaller class of C20-GA2oxs. In this study, the gene encoding a GA 2-oxidase of rice, Oryza sativa GA 2-oxidase 5 (OsGA2ox5), was cloned and characterized. BLASTP analysis showed that OsGA2ox5 belongs to the C20-GA2oxs subfamily, a subfamily of GA2oxs acting on C20-GAs (GA12, GA53). Subcellular localization of OsGA2ox5-YFP in transiently transformed onion epidermal cells revealed the presence of this protein in both of the nucleus and cytoplasm. Real-time PCR analysis, along with GUS staining, revealed that OsGA2ox5 is expressed in the roots, culms, leaves, sheaths and panicles of rice. Rice plants overexpressing OsGA2ox5 exhibited dominant dwarf and GA-deficient phenotypes, with shorter stems and later development of reproductive organs than the wild type. The dwarfism phenotype was partially rescued by the application of exogenous GA3 at a concentration of 10 µM. Ectopic expression of OsGA2ox5 cDNA in Arabidopsis resulted in a similar phenotype. Real-time PCR assays revealed that both GA synthesis-related genes and GA signaling genes were expressed at higher levels in transgenic rice plants than in wild-type rice; OsGA3ox1, which encodes a key enzyme in the last step of the bioactive GAs synthesis pathway, was highly expressed in transgenic rice. The roots of OsGA2ox5-ox plants exhibited increased starch granule accumulation and gravity responses, revealing a role for GA in root starch granule development and gravity responses. Furthermore, rice and Arabidopsis plants overexpressing OsGA2ox5 were more resistant to high-salinity stress than wild-type plants. These results suggest that OsGA2ox5 plays important roles in GAs homeostasis, development, gravity responses and stress tolerance in rice. PMID:24475234

OsGA2ox5, a gibberellin metabolism enzyme, is involved in plant growth, the root gravity response and salt stress.

PubMed

Shan, Chi; Mei, Zhiling; Duan, Jianli; Chen, Haiying; Feng, Huafeng; Cai, Weiming

2014-01-01

Gibberellin (GA) 2-oxidases play an important role in the GA catabolic pathway through 2β-hydroxylation. There are two classes of GA2oxs, i.e., a larger class of C₁₉-GA2oxs and a smaller class of C₂₀-GA2oxs. In this study, the gene encoding a GA 2-oxidase of rice, Oryza sativa GA 2-oxidase 5 (OsGA2ox5), was cloned and characterized. BLASTP analysis showed that OsGA2ox5 belongs to the C₂₀-GA2oxs subfamily, a subfamily of GA2oxs acting on C₂₀-GAs (GA₁₂, GA₅₃). Subcellular localization of OsGA2ox5-YFP in transiently transformed onion epidermal cells revealed the presence of this protein in both of the nucleus and cytoplasm. Real-time PCR analysis, along with GUS staining, revealed that OsGA2ox5 is expressed in the roots, culms, leaves, sheaths and panicles of rice. Rice plants overexpressing OsGA2ox5 exhibited dominant dwarf and GA-deficient phenotypes, with shorter stems and later development of reproductive organs than the wild type. The dwarfism phenotype was partially rescued by the application of exogenous GA3 at a concentration of 10 µM. Ectopic expression of OsGA2ox5 cDNA in Arabidopsis resulted in a similar phenotype. Real-time PCR assays revealed that both GA synthesis-related genes and GA signaling genes were expressed at higher levels in transgenic rice plants than in wild-type rice; OsGA3ox1, which encodes a key enzyme in the last step of the bioactive GAs synthesis pathway, was highly expressed in transgenic rice. The roots of OsGA2ox5-ox plants exhibited increased starch granule accumulation and gravity responses, revealing a role for GA in root starch granule development and gravity responses. Furthermore, rice and Arabidopsis plants overexpressing OsGA2ox5 were more resistant to high-salinity stress than wild-type plants. These results suggest that OsGA2ox5 plays important roles in GAs homeostasis, development, gravity responses and stress tolerance in rice.

Green Manure Addition to Soil Increases Grain Zinc Concentration in Bread Wheat

PubMed Central

Aghili, Forough; Gamper, Hannes A.; Eikenberg, Jost; Khoshgoftarmanesh, Amir H.; Afyuni, Majid; Schulin, Rainer; Jansa, Jan; Frossard, Emmanuel

2014-01-01

Zinc (Zn) deficiency is a major problem for many people living on wheat-based diets. Here, we explored whether addition of green manure of red clover and sunflower to a calcareous soil or inoculating a non-indigenous arbuscular mycorrhizal fungal (AMF) strain may increase grain Zn concentration in bread wheat. For this purpose we performed a multifactorial pot experiment, in which the effects of two green manures (red clover, sunflower), ZnSO4 application, soil γ-irradiation (elimination of naturally occurring AMF), and AMF inoculation were tested. Both green manures were labeled with 65Zn radiotracer to record the Zn recoveries in the aboveground plant biomass. Application of ZnSO4 fertilizer increased grain Zn concentration from 20 to 39 mg Zn kg−1 and sole addition of green manure of sunflower to soil raised grain Zn concentration to 31 mg Zn kg−1. Adding the two together to soil increased grain Zn concentration even further to 54 mg Zn kg−1. Mixing green manure of sunflower to soil mobilized additional 48 µg Zn (kg soil)−1 for transfer to the aboveground plant biomass, compared to the total of 132 µg Zn (kg soil)−1 taken up from plain soil when neither green manure nor ZnSO4 were applied. Green manure amendments to soil also raised the DTPA-extractable Zn in soil. Inoculating a non-indigenous AMF did not increase plant Zn uptake. The study thus showed that organic matter amendments to soil can contribute to a better utilization of naturally stocked soil micronutrients, and thereby reduce any need for major external inputs. PMID:24999738

Iron-binding haemerythrin RING ubiquitin ligases regulate plant iron responses and accumulation

PubMed Central

Kobayashi, Takanori; Nagasaka, Seiji; Senoura, Takeshi; Itai, Reiko Nakanishi; Nakanishi, Hiromi; Nishizawa, Naoko K.

2013-01-01

Iron is essential for most living organisms. Plants transcriptionally induce genes involved in iron acquisition under conditions of low iron availability, but the nature of the deficiency signal and its sensors are unknown. Here we report the identification of new iron regulators in rice, designated Oryza sativa Haemerythrin motif-containing Really Interesting New Gene (RING)- and Zinc-finger protein 1 (OsHRZ1) and OsHRZ2. OsHRZ1, OsHRZ2 and their Arabidopsis homologue BRUTUS bind iron and zinc, and possess ubiquitination activity. OsHRZ1 and OsHRZ2 are susceptible to degradation in roots irrespective of iron conditions. OsHRZ-knockdown plants exhibit substantial tolerance to iron deficiency, and accumulate more iron in their shoots and grains irrespective of soil iron conditions. The expression of iron deficiency-inducible genes involved in iron utilization is enhanced in OsHRZ-knockdown plants, mostly under iron-sufficient conditions. These results suggest that OsHRZ1 and OsHRZ2 are iron-binding sensors that negatively regulate iron acquisition under conditions of iron sufficiency. PMID:24253678

A Historical Review of Progress in the Assessment of Dietary Zinc Intake as an Indicator of Population Zinc Status123

PubMed Central

Gibson, Rosalind S.

2012-01-01

Dietary components influencing zinc (Zn) bioavailability were implicated in the first cases of human Zn deficiency in the Middle East in the 1960s. It was not until the 1980s that isotope tracer studies in humans quantified the effects of the type and/or quantity of Zn, protein, iron, and phytate (myo-inositol hexaphosphate) on Zn absorption in humans and confirmed the dose-dependent inhibitory effect of phytate on Zn absorption. This led to further analysis of the Zn and phytate content of foods. The use of phytate-to-Zn molar ratios as likely estimates of absorbable dietary Zn followed together with an assessment of their relationship with Zn biomarkers in low-income countries (LIC). In the 1990s, increasing knowledge of factors governing Zn-absorption diets led to refinements of Zn requirements and algorithms to estimate dietary Zn bioavailability. Their use highlighted that inadequate Zn intake from plant-based diets were a major etiological factor in morbidity and stunting in LIC, prompting the need to identify indicators of the population’s Zn status. Major advances in analyses of dietary data pioneered by Beaton in 1980s led to the endorsement in 2007 of a dietary Zn indicator based on the prevalence of the population with usual Zn intake below the estimated average requirement for Zn. Risk of Zn deficiency is a public health concern when the prevalence of inadequate Zn intake is >25%. Recent findings that Zn bioavailability from high-phytate, whole-day diets is lower than previous estimates suggest that revision of Zn estimated average requirement for LIC may be warranted. PMID:23153731

Spatial variability assessment of soil nutrients in an intense agricultural area, a case study of Rugao County in Yangtze River Delta Region, China

NASA Astrophysics Data System (ADS)

Zhao, Yongcun; Xu, Xianghua; Darilek, Jeremy Landon; Huang, Biao; Sun, Weixia; Shi, Xuezheng

2009-05-01

Topsoil samples (0-20 cm) ( n = 237) were collected from Rugao County, China. Geostatistical variogram analysis, sequential Gaussian simulation (SGS), and principal component (PC) analysis were applied to assess spatial variability of soil nutrients, identify the possible areas of nutrient deficiency, and explore spatial scale of variability of soil nutrients in the county. High variability of soil nutrient such as soil organic matter (SOM), total nitrogen (TN), available P, K, Fe, Mn, Cu, Zn, and B concentrations were observed. Soil nutrient properties displayed significant differences in their spatial structures, with available Cu having strong spatial dependence, SOM and available P having weak spatial dependence, and other nutrient properties having moderate spatial dependence. The soil nutrient deficiency, defined here as measured nutrient concentrations which do not meet the advisory threshold values specific to the county for dominant crops, namely rice, wheat, and rape seeds, was observed in available K and Zn, and the deficient areas covered 38 and 11%, respectively. The first three PCs of the nine soil nutrient properties explained 62.40% of the total variance. TN and SOM with higher loadings on PC1 are closely related to soil texture derived from different parent materials. The PC2 combined intermediate response variables such as available Zn and P that are likely to be controlled by land use and soil pH. Available B has the highest loading on PC3 and its variability of concentrations may be primarily ascribed to localized anthropogenic influence. The amelioration of soil physical properties (i.e. soil texture) and soil pH may improve the availability of soil nutrients and the sustainability of the agricultural system of Rugao County.

Towards practical cadmium phytoextraction with Noccaea caerulescens.

PubMed

Simmons, R W; Chaney, R L; Angle, J S; Kruatrachue, M; Klinphoklap, S; Reeves, R D; Bellamy, P

2015-01-01

A series of field trials were conducted to investigate the potential of Noccaea caerulescens F.K. Mey [syn. Thlaspi caerulescens J &C Presl. (see Koch and Al-Shehbaz 2004)] populations (genotypes) derived from southern France to phytoextract localized Cd/Zn contamination in Thailand. Soil treatments included pH variation and fertilization level and application of fungicide. N. caerulescens populations were transplanted to the field plots three months after germination and harvested in May, prior to the onset of seasonal rains. During this period growth was rapid with shoot biomass ranging from 0.93-2.2 g plant(-1) (280-650 kg ha(-1)) DW. Shoot Cd and Zn concentrations for the four populations evaluated ranged from 460-600 and 2600-2900 mg kg(-1) DW respectively. Cadmium and Zn Translocation Factors (shoot/root) for the populations tested ranged from 0.91-1.0 and 1.7-2.1 and Bioaccumulation Factors ranged from 12-15 and 1.2-1.3. We conclude that optimizing the use of fungicidal sprays, acidic soil pH, planting density and increasing the effective cropping period will increase rates of Cd and Zn removal enough to facilitate practical Cd phytoextraction from rice paddy soils in Thailand.

GOLD HULL AND INTERNODE2 encodes a primarily multifunctional cinnamyl-alcohol dehydrogenase in rice.

PubMed

Zhang, Kewei; Qian, Qian; Huang, Zejun; Wang, Yiqin; Li, Ming; Hong, Lilan; Zeng, Dali; Gu, Minghong; Chu, Chengcai; Cheng, Zhukuan

2006-03-01

Lignin content and composition are two important agronomic traits for the utilization of agricultural residues. Rice (Oryza sativa) gold hull and internode phenotype is a classical morphological marker trait that has long been applied to breeding and genetics study. In this study, we have cloned the GOLD HULL AND INTERNODE2 (GH2) gene in rice using a map-based cloning approach. The result shows that the gh2 mutant is a lignin-deficient mutant, and GH2 encodes a cinnamyl-alcohol dehydrogenase (CAD). Consistent with this finding, extracts from roots, internodes, hulls, and panicles of the gh2 plants exhibited drastically reduced CAD activity and undetectable sinapyl alcohol dehydrogenase activity. When expressed in Escherichia coli, purified recombinant GH2 was found to exhibit strong catalytic ability toward coniferaldehyde and sinapaldehyde, while the mutant protein gh2 completely lost the corresponding CAD and sinapyl alcohol dehydrogenase activities. Further phenotypic analysis of the gh2 mutant plants revealed that the p-hydroxyphenyl, guaiacyl, and sinapyl monomers were reduced in almost the same ratio compared to the wild type. Our results suggest GH2 acts as a primarily multifunctional CAD to synthesize coniferyl and sinapyl alcohol precursors in rice lignin biosynthesis.

Recycling coffee grounds and tea leaf wastes to improve the yield and mineral content of grains of paddy rice.

PubMed

Morikawa, Claudio K; Saigusa, M

2011-08-30

Coffee grounds and tea leaf wastes exhibit strong affinity for metals such as Fe and Zn. The objective of this experiment was to evaluate the effect of top-dressing application of Fe- and Zn-enriched coffee grounds and tea leaf wastes at the panicle initiation stage on the mineral content of rice grains and the yield of paddy rice. The Fe and Zn contents of brown rice grains increased significantly on application of both coffee and tea waste materials. The concentration of Mn was increased by top-dressing application of coffee waste material only. For Cu, no significant (P < 0.05) differences were found between the control and ferrous sulfate/zinc sulfate treatment. The application of coffee and tea waste materials led to a significant (P < 0.05) increase in the number of grains per panicle, which was reflected in increases in the total number of grains per hill and in grain yield. The top-dressing application of these materials is an excellent method to recycle coffee grounds and tea wastes from coffee shops. Use of these novel materials would not only reduce the waste going to landfill but would also benefit the mineral nutrition of rice consumers at low cost by increasing Fe and Zn levels of rice grains as well as grain yield. Copyright © 2011 Society of Chemical Industry.

Ancient rice cultivar extensively replaces phospholipids with non-phosphorus glycolipid under phosphorus deficiency.

PubMed

Tawaraya, Keitaro; Honda, Soichiro; Cheng, Weiguo; Chuba, Masaru; Okazaki, Yozo; Saito, Kazuki; Oikawa, Akira; Maruyama, Hayato; Wasaki, Jun; Wagatsuma, Tadao

2018-02-07

Recycling of phosphorus (P) from P-containing metabolites is an adaptive strategy of plants to overcome soil P deficiency. This study was aimed at demonstrating differences in lipid remodelling between low-P-tolerant and -sensitive rice cultivars using lipidome profiling. The rice cultivars Akamai (low-P-tolerant) and Koshihikari (low-P-sensitive) were grown in a culture solution with [2 mg l -1 (+P)] or without (-P) phosphate for 21 and 28 days after transplantation. Upper and lower leaves were collected. Lipids were extracted from the leaves and their composition was analysed by liquid chromatography/mass spectrometry (LC-MS). Phospholipids, namely phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG) and phosphatidylinositol (PI), lysophosphatidylcholine (lysoPC), diacylglycerol (DAG), triacylglycerol (TAG) and glycolipids, namely sulfoquinovosyl diacylglycerol (SQDG), digalactosyldiacylglycerol (DGDG), monogalactosyldiacylglycerol (MGDG) and 1,2-diacyl-3-O-alpha-glucuronosyl glycerol (GlcADG), were detected. GlcADG level was higher in both cultivars grown in -P than in +P and the increase was larger in Akamai than in Koshihikari. DGDG, MGDG and SQDG levels were higher in Akamai grown in -P than in +P and the increase was larger in the upper leaves than in the lower leaves. PC, PE, PG and PI levels were lower in both cultivars grown in -P than in +P and the decrease was larger in the lower leaves than in the upper leaves and in Akamai than in Koshihikari. Akamai catabolised more phospholipids in older leaves and synthesised glycolipids in younger leaves. These results suggested that extensive phospholipid replacement with non-phosphorus glycolipids is a mechanism underlying low-P-tolerance in rice cultivars. © 2018 Scandinavian Plant Physiology Society.

Is zinc deficiency a risk factor for atherosclerosis?

PubMed

Beattie, John H; Kwun, In-Sook

2004-02-01

The development of atherosclerosis is influenced by genetic, lifestyle and nutritional risk factors. Zn and metallothionein deficiency can enhance oxidative-stress-related signalling processes in endothelial cells, and since changes in available plasma Zn may affect the Zn status of the endothelium, Zn deficiency could be a risk factor for IHD. Although the association of Zn with many proteins is essential for their function, three key signalling processes are highlighted as being principal targets for the effect of Zn deficiency: the activation of NF-kappaB, the activation of caspase enzymes and the signalling of NO. The need to develop a reliable indicator of Zn status is critical to any epidemiological approach for studying the relationship between Zn status and disease incidence. Studies using appropriate animal models and investigating how the plasma Zn pool influences endothelial intracellular labile Zn would be helpful in appreciating the importance of Zn deficiency in atherogenesis.

The phytoremediation potential of native plants on New Zealand dairy farms.

PubMed

Hahner, Jason L; Robinson, Brett H; Hong-Tao, Zhong; Dickinson, Nicholas M

2014-01-01

Ecological restoration of marginal land and riparian zones in agricultural landscapes in New Zealand enhances the provision of above-ground ecosystem services. We investigated whether native endemic plant assemblages have remediation potential, through modifying soil nutrient and trace element mobility. Analysis of native plant foliage in situ indicated that selective uptake of a range of commonly deficient trace elements including Zn, B, Cu, Mn and Co could provide a browse crop to avoid deficiencies of these elements in livestock, although some native plants may enhance the risk of Mo and Cd toxicity. Native plant rhizospheres were found to modify soil physico-chemistry and are likely to influence lateral and vertical fluxes of chemical elements in drainage waters. Native plants on marginal land in agricultural landscapes could add value to dairy production systems whilst helping to resolve topical environmental issues.

Zinc Deficiency Augments Leptin Production and Exacerbates Macrophage Infiltration into Adipose Tissue in Mice Fed a High-Fat Diet123

PubMed Central

Liu, Ming-Jie; Bao, Shengying; Bolin, Eric R.; Burris, Dara L.; Xu, Xiaohua; Sun, Qinghua; Killilea, David W.; Shen, Qiwen; Ziouzenkova, Ouliana; Belury, Martha A.; Failla, Mark L.; Knoell, Daren L.

2013-01-01

Zinc (Zn) deficiency and obesity are global public health problems. Zn deficiency is associated with obesity and comorbid conditions that include insulin resistance and type 2 diabetes. However, the function of Zn in obesity remains unclear. Using a mouse model of combined high-fat and low-Zn intake (0.5–1.5 mg/kg), we investigated whether Zn deficiency exacerbates the extent of adiposity as well as perturbations in metabolic and immune function. C57BL/6 mice were randomly assigned to receive either a high-fat diet (HFD) or a control (C) diet for 6 wk, followed by further subdivision into 2 additional groups fed Zn-deficient diets (C-Zn, HFD-Zn), along with a C diet and an HFD, for 3 wk (n = 8–9 mice/group). The extent of visceral fat, insulin resistance, or systemic inflammation was unaffected by Zn deficiency. Strikingly, Zn deficiency significantly augmented circulating leptin concentrations (HFD-Zn vs. HFD: 3.15 ± 0.16 vs. 2.59 ± 0.12 μg/L, respectively) and leptin signaling in the liver of obese mice. Furthermore, gene expression of macrophage-specific markers ADAM8 (A disintegrin and metalloproteinase domain-containing protein 8) and CD68 (cluster of differentiation 68) was significantly greater in adipose tissue in the HFD-Zn group than in the HFD group, as confirmed by CD68 protein analysis, indicative of increased macrophage infiltration. Inspection of Zn content and mRNA profiles of all Zn transporters in the adipose tissue revealed alterations of Zn metabolism to obesity and Zn deficiency. Our results demonstrate that Zn deficiency increases leptin production and exacerbates macrophage infiltration into adipose tissue in obese mice, indicating the importance of Zn in metabolic and immune dysregulation in obesity. PMID:23700340

Effect of zinc-lysine on growth, yield and cadmium uptake in wheat (Triticum aestivum L.) and health risk assessment.

PubMed

Rizwan, Muhammad; Ali, Shafaqat; Hussain, Afzal; Ali, Qasim; Shakoor, Muhammad Bilal; Zia-Ur-Rehman, Muhammad; Farid, Mujahid; Asma, Maliha

2017-11-01

Cadmium (Cd) is among the most widespread toxic trace elements found in agricultural soils due to various anthropogenic activities. The role of micronutrient-amino chelates on reducing Cd toxicity in crop plants is recently introduced. The current study was conducted to highlight the role of foliar application of zinc-lysine (Zn-lys) complex on biochemical and growth parameters and Cd uptake in wheat (Triticum aestivum) grown in aged Cd-contaminated soil. Foliar concentration of Zn-lys (0, 10, 20, and 30 mg L -1 ) was applied at different time intervals (2nd, 3rd, 5th and 7th week of sowing) and plants were harvested at maturity. Folliar application of Zinc-lys significantly increased the photosynthesis, grain yield, enzyme activities and Zn contents in different plant tissues. Zinc-lys reduced Cd contents in grains, shoot and root as well as reduced the oxidative stress in wheat linearly in a dose-additive manner. Taken together, Zn-lys chelate efficiently improved wheat growth and fortified Zn contents while reduced Cd concentration in plant in a Zn-deficient Cd-contaminated soil. Although, health risk index (HRI) from the soil sampling area seems to be lower than <1 for Cd but may exceed due to long-term consumption of grains produced from such contaminated soil. Foliar applied Zn-lys reduced HRI which may help to reduce health risks associated with Cd. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparison between Arabidopsis and Rice for Main Pathways of K(+) and Na(+) Uptake by Roots.

PubMed

Nieves-Cordones, Manuel; Martínez, Vicente; Benito, Begoña; Rubio, Francisco

2016-01-01

K(+) is an essential macronutrient for plants. It is acquired by specific uptake systems located in roots. Although the concentrations of K(+) in the soil solution are widely variable, K(+) nutrition is secured by uptake systems that exhibit different affinities for K(+). Two main systems have been described for root K(+) uptake in several species: the high-affinity HAK5-like transporter and the inward-rectifier AKT1-like channel. Other unidentified systems may be also involved in root K(+) uptake, although they only seem to operate when K(+) is not limiting. The use of knock-out lines has allowed demonstrating their role in root K(+) uptake in Arabidopsis and rice. Plant adaptation to the different K(+) supplies relies on the finely tuned regulation of these systems. Low K(+)-induced transcriptional up-regulation of the genes encoding HAK5-like transporters occurs through a signal cascade that includes changes in the membrane potential of root cells and increases in ethylene and reactive oxygen species concentrations. Activation of AKT1 channels occurs through phosphorylation by the CIPK23/CBL1 complex. Recently, activation of the Arabidopsis HAK5 by the same complex has been reported, pointing to CIPK23/CBL as a central regulator of the plant's adaptation to low K(+). Na(+) is not an essential plant nutrient but it may be beneficial for some plants. At low concentrations, Na(+) improves growth, especially under K(+) deficiency. Thus, high-affinity Na(+) uptake systems have been described that belong to the HKT and HAK families of transporters. At high concentrations, typical of saline environments, Na(+) accumulates in plant tissues at high concentrations, producing alterations that include toxicity, water deficit and K(+) deficiency. Data concerning pathways for Na(+) uptake into roots under saline conditions are still scarce, although several possibilities have been proposed. The apoplast is a significant pathway for Na(+) uptake in rice grown under salinity conditions, but in other plant species different mechanisms involving non-selective cation channels or transporters are under discussion.

Phosphorus uptake, partitioning and redistribution during grain filling in rice

PubMed Central

Julia, Cécile; Wissuwa, Matthias; Kretzschmar, Tobias; Jeong, Kwanho; Rose, Terry

2016-01-01

Backgrounds and Aims In cultivated rice, phosphorus (P) in grains originates from two possible sources, namely exogenous (post-flowering root P uptake from soil) or endogenous (P remobilization from vegetative parts) sources. This study investigates P partitioning and remobilization in rice plants throughout grain filling to resolve contributions of P sources to grain P levels in rice. Methods Rice plants (Oryza sativa ‘IR64’) were grown under P-sufficient or P-deficient conditions in the field and in hydroponics. Post-flowering uptake, partitioning and re-partitioning of P was investigated by quantifying tissue P levels over the grain filling period in the field conditions, and by employing 33P isotope as a tracer in the hydroponic study. Key Results Post-flowering P uptake represented 40–70 % of the aerial plant P accumulation at maturity. The panicle was the main P sink in all studies, and the amount of P potentially remobilized from vegetative tissues to the panicle during grain filling was around 20 % of the total aerial P measured at flowering. In hydroponics, less than 20 % of the P tracer taken up at 9 d after flowering (DAF) was found in the above-ground tissues at 14 DAF and half of it was partitioned to the panicle in both P treatments. Conclusions The results demonstrate that P uptake from the soil during grain filling is a critical contributor to the P content in grains in irrigated rice. The P tracer study suggests that the mechanism of P loading into grains involves little direct transfer of post-flowering P uptake to the grain but rather substantial mobilization of P that was previously taken up and stored in vegetative tissues. PMID:27590335

Efficacy of cheap amendments for stabilizing trace elements in contaminated paddy fields.

PubMed

Huang, Tai-Hsiang; Lai, Yun-Jie; Hseu, Zeng-Yei

2018-05-01

In situ stabilization of trace elements by adding cheap amendments is an emerging technology for large-scale soil remediation. Various amendments have been examined well in the literature, but related have focused predominantly on short-term laboratory scale incubation or pot experiments. This study applied dolomitic lime at 40 ton ha -1 , oyster shell (OS) at 80 ton ha -1 , and sugarcane bagasse compost (SC) at 60 ton ha -1 to a paddy field in Taiwan for two rice (Oryza sativa L.) cropping seasons. The aims of study were to gain an understanding of the bioavailable concentrations of Cr, Ni, Cu, and Zn in the amended soil and the metal uptake of rice for practical amendment use in field-scale remediation of contaminated soils. The treatments of lime and OS significantly (p < 0.05) decreased the 0.1 N HCl-extractable metals in the soil. The increase in soil pH was the key factor in decreasing the bioavailable pool of metals in the soil by using lime and OS. The concentrations of Cu, Zn, and Ni in the brown rice were substantially reduced only through the addition of OS, and thus OS met the requirement of being a cheap, locally available, and environmentally compatible amendment for field-scale soil remediation. The translocation of Cr in rice plants is heavily restricted, and thus no significant differences in Cr uptake by rice grain were observed between the different amendment treatments. However, SC is not recommended as an immobilization agent because it caused a pH decrease in the amended soil. Copyright © 2018 Elsevier Ltd. All rights reserved.

Mitochondrial GPX1 silencing triggers differential photosynthesis impairment in response to salinity in rice plants.

PubMed

Lima-Melo, Yugo; Carvalho, Fabricio E L; Martins, Márcio O; Passaia, Gisele; Sousa, Rachel H V; Neto, Milton C Lima; Margis-Pinheiro, Márcia; Silveira, Joaquim A G

2016-08-01

The physiological role of plant mitochondrial glutathione peroxidases is scarcely known. This study attempted to elucidate the role of a rice mitochondrial isoform (GPX1) in photosynthesis under normal growth and salinity conditions. GPX1 knockdown rice lines (GPX1s) were tested in absence and presence of 100 mM NaCl for 6 d. Growth reduction of GPX1s line under non-stressful conditions, compared with non-transformed (NT) plants occurred in parallel to increased H2 O2 and decreased GSH contents. These changes occurred concurrently with photosynthesis impairment, particularly in Calvin cycle's reactions, since photochemical efficiency did not change. Thus, GPX1 silencing and downstream molecular/metabolic changes modulated photosynthesis differentially. In contrast, salinity induced reduction in both phases of photosynthesis, which were more impaired in silenced plants. These changes were associated with root morphology alterations but not shoot growth. Both studied lines displayed increased GPX activity but H2 O2 content did not change in response to salinity. Transformed plants exhibited lower photorespiration, water use efficiency and root growth, indicating that GPX1 could be important to salt tolerance. Growth reduction of GPX1s line might be related to photosynthesis impairment, which in turn could have involved a cross talk mechanism between mitochondria and chloroplast originated from redox changes due to GPX1 deficiency. © 2016 Institute of Botany, Chinese Academy of Sciences.

Expression of TpNRAMP5, a metal transporter from Polish wheat (Triticum polonicum L.), enhances the accumulation of Cd, Co and Mn in transgenic Arabidopsis plants.

PubMed

Peng, Fan; Wang, Chao; Zhu, Jianshu; Zeng, Jian; Kang, Houyang; Fan, Xing; Sha, Lina; Zhang, Haiqin; Zhou, Yonghong; Wang, Yi

2018-06-01

TpRNAMP5 is mainly expressed in the plasma membrane of roots and basal stems. It functions as a metal transporter for Cd, Mn and Co accumulation. Numerous natural resistance-associated macrophage proteins (NRAMPs) have been functionally identified in various plant species, including Arabidopsis, rice, soybean and tobacco, but no information is available on NRAMP genes in wheat. In this study, we isolated a TpNRAMP5 from dwarf Polish wheat (DPW, Triticum polonicum L.), a species with high tolerance to Cd and Zn. Expression pattern analysis revealed that TpNRAMP5 is mainly expressed in roots and basal stems of DPW. TpNRAMP5 was localized at the plasma membrane of Arabidopsis leaf protoplast. Expression of TpNRAMP5 in yeast significantly increased yeast sensitivity to Cd and Co, but not Zn, and enhanced Cd and Co concentrations. Expression of TpNRAMP5 in Arabidopsis significantly increased Cd, Co and Mn concentrations in roots, shoots and whole plants, but had no effect on Fe and Zn concentrations. These results indicate that TpNRAMP5 is a metal transporter enhancing the accumulation of Cd, Co and Mn, but not Zn and Fe. Genetic manipulation of TpNRAMP5 can be applied in the future to limit the transfer of Cd from soil to wheat grains, thereby protecting human health.

Transcriptome analysis of phosphorus stress responsiveness in the seedlings of Dongxiang wild rice (Oryza rufipogon Griff.).

PubMed

Deng, Qian-Wen; Luo, Xiang-Dong; Chen, Ya-Ling; Zhou, Yi; Zhang, Fan-Tao; Hu, Biao-Lin; Xie, Jian-Kun

2018-03-15

Low phosphorus availability is a major factor restricting rice growth. Dongxiang wild rice (Oryza rufipogon Griff.) has many useful genes lacking in cultivated rice, including stress resistance to phosphorus deficiency, cold, salt and drought, which is considered to be a precious germplasm resource for rice breeding. However, the molecular mechanism of regulation of phosphorus deficiency tolerance is not clear. In this study, cDNA libraries were constructed from the leaf and root tissues of phosphorus stressed and untreated Dongxiang wild rice seedlings, and transcriptome sequencing was performed with the goal of elucidating the molecular mechanisms involved in phosphorus stress response. The results indicated that 1184 transcripts were differentially expressed in the leaves (323 up-regulated and 861 down-regulated) and 986 transcripts were differentially expressed in the roots (756 up-regulated and 230 down-regulated). 43 genes were up-regulated both in leaves and roots, 38 genes were up-regulated in roots but down-regulated in leaves, and only 2 genes were down-regulated in roots but up-regulated in leaves. Among these differentially expressed genes, the detection of many transcription factors and functional genes demonstrated that multiple regulatory pathways were involved in phosphorus deficiency tolerance. Meanwhile, the differentially expressed genes were also annotated with gene ontology terms and key pathways via functional classification and Kyoto Encyclopedia of Gene and Genomes pathway mapping, respectively. A set of the most important candidate genes was then identified by combining the differentially expressed genes found in the present study with previously identified phosphorus deficiency tolerance quantitative trait loci. The present work provides abundant genomic information for functional dissection of the phosphorus deficiency resistance of Dongxiang wild rice, which will be help to understand the biological regulatory mechanisms of phosphorus deficiency tolerance in Dongxiang wild rice.

Optimised synthesis of ZnO-nano-fertiliser through green chemistry: boosted growth dynamics of economically important L. esculentum.

PubMed

Jabeen, Nyla; Maqbool, Qaisar; Bibi, Tahira; Nazar, Mudassar; Hussain, Syed Z; Hussain, Talib; Jan, Tariq; Ahmad, Ishaq; Maaza, Malik; Anwaar, Sadaf

2018-06-01

Mounting-up economic losses to annual crops yield due to micronutrient deficiency, fertiliser inefficiency and increasing microbial invasions (e.g. Xanthomonas cempestri attack on tomatoes) are needed to be solved via nano-biotechnology. So keeping this in view, the authors' current study presents the new horizon in the field of nano-fertiliser with highly nutritive and preservative effect of green fabricated zinc oxide-nanostructures (ZnO-NSs) during Lycopersicum esculentum (tomato) growth dynamics. ZnO-NS prepared via green chemistry possesses highly homogenous crystalline structures well-characterised through ultraviolet and visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscope. The ZnO-NS average size was found as small as 18 nm having a crystallite size of 5 nm. L. esculentum were grown in different concentrations of ZnO-NS to examine the different morphological parameters includes time of seed germination, germination percentage, the number of plant leaves, the height of the plant, average number of branches, days count for flowering and fruiting time period along with fruit quantity. Promising results clearly predict that bio-fabricated ZnO-NS at optimum concentration resulted as growth booster and dramatically triggered the plant yield.

Analysis of Chromatin Regulators Reveals Specific Features of Rice DNA Methylation Pathways.

PubMed

Tan, Feng; Zhou, Chao; Zhou, Qiangwei; Zhou, Shaoli; Yang, Wenjing; Zhao, Yu; Li, Guoliang; Zhou, Dao-Xiu

2016-07-01

Plant DNA methylation that occurs at CG, CHG, and CHH sites (H = A, C, or T) is a hallmark of the repression of repetitive sequences and transposable elements (TEs). The rice (Oryza sativa) genome contains about 40% repetitive sequence and TEs and displays specific patterns of genome-wide DNA methylation. The mechanism responsible for the specific methylation patterns is unclear. Here, we analyzed the function of OsDDM1 (Deficient in DNA Methylation 1) and OsDRM2 (Deficient in DNA Methylation 1) in genome-wide DNA methylation, TE repression, small RNA accumulation, and gene expression. We show that OsDDM1 is essential for high levels of methylation at CHG and, to a lesser extent, CG sites in heterochromatic regions and also is required for CHH methylation that mainly locates in the genic regions of the genome. In addition to a large member of TEs, loss of OsDDM1 leads to hypomethylation and up-regulation of many protein-coding genes, producing very severe growth phenotypes at the initial generation. Importantly, we show that OsDRM2 mutation results in a nearly complete loss of CHH methylation and derepression of mainly small TE-associated genes and that OsDDM1 is involved in facilitating OsDRM2-mediated CHH methylation. Thus, the function of OsDDM1 and OsDRM2 defines distinct DNA methylation pathways in the bulk of DNA methylation of the genome, which is possibly related to the dispersed heterochromatin across chromosomes in rice and suggests that DNA methylation mechanisms may vary among different plant species. © 2016 American Society of Plant Biologists. All Rights Reserved.

Enterococcus faecium LKE12 Cell-Free Extract Accelerates Host Plant Growth via Gibberellin and Indole-3-Acetic Acid Secretion.

PubMed

Lee, Ko-Eun; Radhakrishnan, Ramalingam; Kang, Sang-Mo; You, Young-Hyun; Joo, Gil-Jae; Lee, In-Jung; Ko, Jae-Hwan; Kim, Jin-Ho

2015-09-01

The use of microbial extracts containing plant hormones is a promising technique to improve crop growth. Little is known about the effect of bacterial cell-free extracts on plant growth promotion. This study, based on phytohormonal analyses, aimed at exploring the potential mechanisms by which Enterococcus faecium LKE12 enhances plant growth in oriental melon. A bacterial strain, LKE12, was isolated from soil, and further identified as E. faecium by 16S rDNA sequencing and phylogenetic analysis. The plant growth-promoting ability of an LKE12 bacterial culture was tested in a gibberellin (GA)-deficient rice dwarf mutant (waito-C) and a normal GA biosynthesis rice cultivar (Hwayongbyeo). E. faecium LKE12 significantly improved the length and biomass of rice shoots in both normal and dwarf cultivars through the secretion of an array of gibberellins (GA1, GA3, GA7, GA8, GA9, GA12, GA19, GA20, GA24, and GA53), as well as indole-3-acetic acid (IAA). To the best of our knowledge, this is the first study indicating that E. faecium can produce GAs. Increases in shoot and root lengths, plant fresh weight, and chlorophyll content promoted by E. faecium LKE12 and its cell-free extract inoculated in oriental melon plants revealed a favorable interaction of E. faecium LKE12 with plants. Higher plant growth rates and nutrient contents of magnesium, calcium, sodium, iron, manganese, silicon, zinc, and nitrogen were found in cell-free extract-treated plants than in control plants. The results of the current study suggest that E. faecium LKE12 promotes plant growth by producing GAs and IAA; interestingly, the exogenous application of its cell-free culture extract can be a potential strategy to accelerate plant growth.

A preliminary study on identification of Thai rice samples by INAA and statistical analysis

NASA Astrophysics Data System (ADS)

Kongsri, S.; Kukusamude, C.

2017-09-01

This study aims to investigate the elemental compositions in 93 Thai rice samples using instrumental neutron activation analysis (INAA) and to identify rice according to their types and rice cultivars using statistical analysis. As, Mg, Cl, Al, Br, Mn, K, Rb and Zn in Thai jasmine rice and Sung Yod rice samples were successfully determined by INAA. The accuracy and precision of the INAA method were verified by SRM 1568a Rice Flour. All elements were found to be in a good agreement with the certified values. The precisions in term of %RSD were lower than 7%. The LODs were obtained in range of 0.01 to 29 mg kg-1. The concentration of 9 elements distributed in Thai rice samples was evaluated and used as chemical indicators to identify the type of rice samples. The result found that Mg, Cl, As, Br, Mn, K, Rb, and Zn concentrations in Thai jasmine rice samples are significantly different but there was no evidence that Al is significantly different from concentration in Sung Yod rice samples at 95% confidence interval. Our results may provide preliminary information for discrimination of rice samples and may be useful database of Thai rice.

Cell wall targeted in planta iron accumulation enhances biomass conversion and seed iron concentration in Arabidopsis and rice.

PubMed

Yang, Haibing; Wei, Hui; Ma, Guojie; Antunes, Mauricio S; Vogt, Stefan; Cox, Joseph; Zhang, Xiao; Liu, Xiping; Bu, Lintao; Gleber, S Charlotte; Carpita, Nicholas C; Makowski, Lee; Himmel, Michael E; Tucker, Melvin P; McCann, Maureen C; Murphy, Angus S; Peer, Wendy A

2016-10-01

Conversion of nongrain biomass into liquid fuel is a sustainable approach to energy demands as global population increases. Previously, we showed that iron can act as a catalyst to enhance the degradation of lignocellulosic biomass for biofuel production. However, direct addition of iron catalysts to biomass pretreatment is diffusion-limited, would increase the cost and complexity of biorefinery unit operations and may have deleterious environmental impacts. Here, we show a new strategy for in planta accumulation of iron throughout the volume of the cell wall where iron acts as a catalyst in the deconstruction of lignocellulosic biomass. We engineered CBM-IBP fusion polypeptides composed of a carbohydrate-binding module family 11 (CBM11) and an iron-binding peptide (IBP) for secretion into Arabidopsis and rice cell walls. CBM-IBP transformed Arabidopsis and rice plants show significant increases in iron accumulation and biomass conversion compared to respective controls. Further, CBM-IBP rice shows a 35% increase in seed iron concentration and a 40% increase in seed yield in greenhouse experiments. CBM-IBP rice potentially could be used to address iron deficiency, the most common and widespread nutritional disorder according to the World Health Organization. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Nitric Oxide Is Associated with Long-Term Zinc Tolerance in Solanum nigrum1[W

PubMed Central

Xu, Jin; Yin, Hengxia; Li, Yulong; Liu, Xiaojing

2010-01-01

Nitric oxide (NO) has been identified as a signal molecule that interplays with reactive oxygen species in response to heavy metal stresses. Roles of NO in regulating cadmium toxicity and iron deficiency have been proposed; however, the function of NO in zinc (Zn) tolerance in plants remains unclear. Here, we investigated NO accumulation and its role in plant Zn tolerance. Zn-induced NO production promoted an increase in reactive oxygen species accumulation in Solanum nigrum roots by modulating the expression and activity of antioxidative enzymes. Subsequently, programmed cell death (PCD) was observed in primary root tips. Inhibiting NO accumulation by 2-phenyl-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide (a specific NO scavenger) or NG-nitro-l-arginine-methyl ester (a NO synthase inhibitor) prevented the increase of superoxide radical and hydrogen peroxide as well as the subsequent cell death in the root tips, supporting the role of NO in Zn-induced PCD in the root tips. Zn-induced NO production affected the length of primary roots, the number of lateral roots, and root hair growth and thereby modulated root system architecture and activity. Investigation of metal contents in Zn-treated roots suggests that NO is required for metal (especially iron) uptake and homeostasis in plants exposed to excess Zn. Taken together, our results indicate that NO production and the subsequent PCD in root tips exposed to excess Zn are favorable for the S. nigrum seedling response to long-term Zn toxicity by modulating root system architecture and subsequent adaptation to Zn stress. PMID:20855519

Intrauterine Zn Deficiency Favors Thyrotropin-Releasing Hormone-Increasing Effects on Thyrotropin Serum Levels and Induces Subclinical Hypothyroidism in Weaned Rats.

PubMed

Alcántara-Alonso, Viridiana; Alvarez-Salas, Elena; Matamoros-Trejo, Gilberto; de Gortari, Patricia

2017-10-18

Individuals who consume a diet deficient in zinc (Zn-deficient) develop alterations in hypothalamic-pituitary-thyroid axis function, i.e., a low metabolic rate and cold insensitivity. Although those disturbances are related to primary hypothyroidism, intrauterine or postnatal Zn-deficient adults have an increased thyrotropin (TSH) concentration, but unchanged thyroid hormone (TH) levels and decreased body weight. This does not support the view that the hypothyroidism develops due to a low Zn intake. In addition, intrauterine or postnatal Zn-deficiency in weaned and adult rats reduces the activity of pyroglutamyl aminopeptidase II (PPII) in the medial-basal hypothalamus (MBH). PPII is an enzyme that degrades thyrotropin-releasing hormone (TRH). This hypothalamic peptide stimulates its receptor in adenohypophysis, thereby increasing TSH release. We analyzed whether earlier low TH is responsible for the high TSH levels reported in adults, or if TRH release is enhanced by Zn deficiency at weaning. Dams were fed a 2 ppm Zn-deficient diet in the period from one week prior to gestation and up to three weeks after delivery. We found a high release of hypothalamic TRH, which along with reduced MBH PPII activity, increased TSH levels in Zn-deficient pups independently of changes in TH concentration. We found that primary hypothyroidism did not develop in intrauterine Zn-deficient weaned rats and we confirmed that metal deficiency enhances TSH levels since early-life, favoring subclinical hypothyroidism development which remains into adulthood.

OsDOG, a gibberellin-induced A20/AN1 zinc-finger protein, negatively regulates gibberellin-mediated cell elongation in rice.

PubMed

Liu, Yaju; Xu, Yunyuan; Xiao, Jun; Ma, Qibin; Li, Dan; Xue, Zhen; Chong, Kang

2011-07-01

The A20/AN1 zinc-finger proteins (ZFPs) play pivotal roles in animal immune responses and plant stress responses. From previous gibberellin (GA) microarray data and A20/AN1 ZFP family member association, we chose Oryza sativa dwarf rice with overexpression of gibberellin-induced gene (OsDOG) to examine its function in the GA pathway. OsDOG was induced by gibberellic acid (GA(3)) and repressed by the GA-synthesis inhibitor paclobutrazol. Different transgenic lines with constitutive expression of OsDOG showed dwarf phenotypes due to deficiency of cell elongation. Additional GA(1) and real-time PCR quantitative assay analyses confirmed that the decrease of GA(1) in the overexpression lines resulted from reduced expression of GA3ox2 and enhanced expression of GA2ox1 and GA2ox3. Adding exogenous GA rescued the constitutive expression phenotypes of the transgenic lines. OsDOG has a novel function in regulating GA homeostasis and in negative maintenance of plant cell elongation in rice. Copyright © 2011 Elsevier GmbH. All rights reserved.

Comparison between Arabidopsis and Rice for Main Pathways of K+ and Na+ Uptake by Roots

PubMed Central

Nieves-Cordones, Manuel; Martínez, Vicente; Benito, Begoña; Rubio, Francisco

2016-01-01

K+ is an essential macronutrient for plants. It is acquired by specific uptake systems located in roots. Although the concentrations of K+ in the soil solution are widely variable, K+ nutrition is secured by uptake systems that exhibit different affinities for K+. Two main systems have been described for root K+ uptake in several species: the high-affinity HAK5-like transporter and the inward-rectifier AKT1-like channel. Other unidentified systems may be also involved in root K+ uptake, although they only seem to operate when K+ is not limiting. The use of knock-out lines has allowed demonstrating their role in root K+ uptake in Arabidopsis and rice. Plant adaptation to the different K+ supplies relies on the finely tuned regulation of these systems. Low K+-induced transcriptional up-regulation of the genes encoding HAK5-like transporters occurs through a signal cascade that includes changes in the membrane potential of root cells and increases in ethylene and reactive oxygen species concentrations. Activation of AKT1 channels occurs through phosphorylation by the CIPK23/CBL1 complex. Recently, activation of the Arabidopsis HAK5 by the same complex has been reported, pointing to CIPK23/CBL as a central regulator of the plant’s adaptation to low K+. Na+ is not an essential plant nutrient but it may be beneficial for some plants. At low concentrations, Na+ improves growth, especially under K+ deficiency. Thus, high-affinity Na+ uptake systems have been described that belong to the HKT and HAK families of transporters. At high concentrations, typical of saline environments, Na+ accumulates in plant tissues at high concentrations, producing alterations that include toxicity, water deficit and K+ deficiency. Data concerning pathways for Na+ uptake into roots under saline conditions are still scarce, although several possibilities have been proposed. The apoplast is a significant pathway for Na+ uptake in rice grown under salinity conditions, but in other plant species different mechanisms involving non-selective cation channels or transporters are under discussion. PMID:27458473

The spatial expression and regulation of transcription factors IDEF1 and IDEF2

PubMed Central

Kobayashi, Takanori; Ogo, Yuko; Aung, May Sann; Nozoye, Tomoko; Itai, Reiko Nakanishi; Nakanishi, Hiromi; Yamakawa, Takashi; Nishizawa, Naoko K.

2010-01-01

Background and Aims Under conditions of low iron availability, rice plants induce genes involved in iron uptake and utilization. The iron deficiency-responsive cis-acting element binding factors 1 and 2 (IDEF1 and IDEF2) regulate transcriptional response to iron deficiency in rice roots. Clarification of the functions of IDEF1 and IDEF2 could uncover the gene regulation mechanism. Methods Spatial patterns of IDEF1 and IDEF2 expression were analysed by histochemical staining of IDEF1 and IDEF2 promoter-GUS transgenic rice lines. Expression patterns of the target genes of IDEF1 and IDEF2 were analysed using transformants with induced or repressed expression of IDEF1 or IDEF2 grown in iron-rich or in iron-deficient solutions for 1 d. Key Results IDEF1 and IDEF2 were highly expressed in the basal parts of the lateral roots and vascular bundles. IDEF1 and IDEF2 expression was dominant in leaf mesophyll and vascular cells, respectively. These expression patterns were similar under both iron-deficient and iron-sufficient conditions. IDEF1 was strongly expressed in pollen, ovaries, the aleurone layer and embryo. IDEF2 was expressed in pollen, ovaries and the dorsal vascular region of the endosperm. During seed germination, IDEF1 and IDEF2 were expressed in the endosperm and embryo. Expression of IDEF1 target genes was regulated in iron-rich roots similar to early iron-deficiency stages. In addition, the expression patterns of IDEF2 target genes were similar between iron-rich conditions and early or subsequent iron deficiency. Conclusions IDEF1 and IDEF2 are constitutively expressed during both vegetative and reproductive stages. The spatial expression patterns of IDEF1 and IDEF2 overlap with their target genes in restricted cell types, but not in all cells. The spatial expression patterns and gene regulation of IDEF1 and IDEF2 in roots are generally conserved under conditions of iron sufficiency and deficiency, suggesting complicated interactions with unknown factors for sensing and transmitting iron-deficiency signals. PMID:20197292

Silicon alleviates simulated acid rain stress of Oryza sativa L. seedlings by adjusting physiology activity and mineral nutrients.

PubMed

Ju, Shuming; Wang, Liping; Yin, Ningning; Li, Dan; Wang, Yukun; Zhang, Cuiying

2017-11-01

Silicon (Si) has been a modulator in plants under abiotic stresses, such as acid rain. To understand how silicon made an effect on rice (Oryza sativa L.) exposed to simulated acid rain (SAR) stress, the growth, physiologic activity, and mineral nutrient content in leaves of rice were investigated. The results showed that combined treatments with Si (1.0, 2.0, or 4.0 mM) and SAR (pH 4.0, 3.0, or 2.0) obviously improved the rice growth compared with the single treatment with SAR. Incorporation of Si into SAR treatment decreased malondialdehyde (MDA) content; increased soluble protein and proline contents; promoted CAT, POD, SOD, and APX activity; and maintained the K, Ca, Mg, Fe, Zn, Cu content balance in leaves of rice seedlings under SAR stress. The moderate concentration of Si (2.0 mM) was better than the low and high concentration of Si (1.0 and 4.0 mM). Therefore, application of Si could be a better strategy for maintaining the crop productivity in acid rain regions.

Distinctive phytotoxic effects of Cd and Ni on membrane functionality.

PubMed

Sanz, Amparo; Llamas, Andreu; Ullrich, Cornelia I

2009-10-01

Metal ions essential for plant growth, such as Fe, Mn, Ni, Cu or Zn, are taken up by plants from the soil solution through metal transporters at the plasma membrane, mainly of the ZIP and Nramp families. These transport systems, however, can also give entry to other metals (Al, Cd, Hg, Pb). Non-nutritive elements, as well as the essential nutrients at higher than metabolic concentrations, can cause phytotoxicity. We have studied previously the effects of an essential (Ni) and a non essential (Cd) heavy metal on root cell plasma membranes, the first selective barrier encountered when entering the plant, using rice as model plant. Distinctive effects of Cd and Ni on membrane function (i.e., Em and membrane permeability) were observed in the short term. We have now confirmed the pattern of Em changes caused by Cd and Ni using barley roots and have also followed the effects of both metals in longer term in rice. Our data indicate that the distinct effects caused by Cd and Ni are due to differences in cellular responses, triggered when entering the cytoplasm (i.e., an efficient detoxifying mechanism for Cd), more than to different direct effects on membranes.

Baseline study on essential and trace elements in polished rice from South Korea.

PubMed

Jung, Myung Chae; Yun, Seong-Taek; Lee, Jin-Soo; Lee, Jong-Un

2005-09-01

In 2000, 63 (polished) white rice samples were collected in eight administrative areas all over South Korea and analyzed for 16 elements by inductively coupled plasma atomic emission spectrometry (ICP-AES). Potassium had the highest content, next to Mg, Ca, Si, Zn, Na, Al and Fe. Most of the samples contained worldwide average concentrations of essential and trace elements in rice grains reported by various researches. For inter-area differences in those elements in the rice, the statistical analysis showed no significant differences (p > 0.05) among the eight administrative areas, suggesting that inter-area differences were not substantial in most cases. Thus, the present data can be used as national background levels of elements in rice produced in South Korea. Using the published data on daily consumption of rice in South Korea, it was possible to estimate the daily intake of As, Cd, Cu, Pb and Zn via rice. The results showed that a regular consumption of rice produced in Korea plays an important role in accumulation of essential and trace elements in Korean, especially for farm-households consuming relatively large amounts of rice.

Influence of Species of Vesicular-Arbuscular Mycorrhizal Fungi and Phosphorus Nutrition on Growth, Development, and Mineral Nutrition of Potato (Solanum tuberosum L.).

PubMed

McArthur, DAJ.; Knowles, N. R.

1993-07-01

Growth, development, and mineral physiology of potato (Solanum tuberosum L.) plants in response to infection by three species of vesicular-arbuscular mycorrhizal (VAM) fungi and different levels of P nutrition were characterized. P deficiency in no-P and low-P (0.5 mM) nonmycorrhizal plants developed between 28 and 84 d after planting. By 84 d after planting, P deficiency decreased plant relative growth rate such that no-P and low-P plants had, respectively, 65 and 45% less dry mass and 76 and 55% less total P than plants grown with high P (2.5 mM). A severe reduction in leaf area was also evident, because P deficiency induced a restriction of lateral bud growth and leaf expansion and, also, decreased the relative plant allocation of dry matter to leaf growth. Root growth was less influenced by P deficiency than either leaf or stem growth. Moreover, P-deficient plants accumulated a higher proportion of total available P than high-P plants, indicating that P stress had enhanced root efficiency of P acquisition. Plant P deficiency did not alter the shoot concentration of N, K, Mg, or Fe; however, the total accumulation of these mineral nutrients in shoots of P-stressed plants was substantially less than that of high-P plants. P uptake by roots was enhanced by each of the VAM symbionts by 56 d after planting and at all levels of abiotic P supply. Species differed in their ability to colonize roots and similarly to produce a plant growth response. In this regard, Glomus intraradices (Schenck and Smith) enhanced plant growth the most, whereas Glomus dimorphicum (Boyetchko and Tewari) was least effective, and Glomus mosseae ([Nicol. and Gerd.] Gerd. and Trappe) produced an intermediate growth response. The partial alleviation of P deficiency in no-P and low-P plants by VAM fungi stimulated uptake of N, K, Mg, Fe, and Zn. VAM fungi enhanced shoot concentrations of P, N, and Mg by 28 d after planting and, through a general improvement of overall plant mineral nutrition, promoted plant growth and development.

GOLD HULL AND INTERNODE2 Encodes a Primarily Multifunctional Cinnamyl-Alcohol Dehydrogenase in Rice1

PubMed Central

Zhang, Kewei; Qian, Qian; Huang, Zejun; Wang, Yiqin; Li, Ming; Hong, Lilan; Zeng, Dali; Gu, Minghong; Chu, Chengcai; Cheng, Zhukuan

2006-01-01

Lignin content and composition are two important agronomic traits for the utilization of agricultural residues. Rice (Oryza sativa) gold hull and internode phenotype is a classical morphological marker trait that has long been applied to breeding and genetics study. In this study, we have cloned the GOLD HULL AND INTERNODE2 (GH2) gene in rice using a map-based cloning approach. The result shows that the gh2 mutant is a lignin-deficient mutant, and GH2 encodes a cinnamyl-alcohol dehydrogenase (CAD). Consistent with this finding, extracts from roots, internodes, hulls, and panicles of the gh2 plants exhibited drastically reduced CAD activity and undetectable sinapyl alcohol dehydrogenase activity. When expressed in Escherichia coli, purified recombinant GH2 was found to exhibit strong catalytic ability toward coniferaldehyde and sinapaldehyde, while the mutant protein gh2 completely lost the corresponding CAD and sinapyl alcohol dehydrogenase activities. Further phenotypic analysis of the gh2 mutant plants revealed that the p-hydroxyphenyl, guaiacyl, and sinapyl monomers were reduced in almost the same ratio compared to the wild type. Our results suggest GH2 acts as a primarily multifunctional CAD to synthesize coniferyl and sinapyl alcohol precursors in rice lignin biosynthesis. PMID:16443696

A Rice Phenolic Efflux Transporter Is Essential for Solubilizing Precipitated Apoplasmic Iron in the Plant Stele*

PubMed Central

Ishimaru, Yasuhiro; Kakei, Yusuke; Shimo, Hugo; Bashir, Khurram; Sato, Yutaka; Sato, Yuki; Uozumi, Nobuyuki; Nakanishi, Hiromi; Nishizawa, Naoko K.

2011-01-01

Iron deficiency is one of the major agricultural problems, as 30% of the arable land of the world is too alkaline for optimal crop production, rendering plants short of available iron despite its abundance. To take up apoplasmic precipitated iron, plants secrete phenolics such as protocatechuic acid (PCA) and caffeic acid. The molecular pathways and genes of iron uptake strategies are already characterized, whereas the molecular mechanisms of phenolics synthesis and secretion have not been clarified, and no phenolics efflux transporters have been identified in plants yet. Here we describe the identification of a phenolics efflux transporter in rice. We identified a cadmium-accumulating rice mutant in which the amount of PCA and caffeic acid in the xylem sap was dramatically reduced and hence named it phenolics efflux zero 1 (pez1). PEZ1 localized to the plasma membrane and transported PCA when expressed in Xenopus laevis oocytes. PEZ1 localized mainly in the stele of roots. In the roots of pez1, precipitated apoplasmic iron increased. The growth of PEZ1 overexpression lines was severely restricted, and these lines accumulated more iron as a result of the high solubilization of precipitated apoplasmic iron in the stele. We show that PEZ1 is responsible for an increase of PCA concentration in the xylem sap and is essential for the utilization of apoplasmic precipitated iron in the stele. PMID:21602276

Identification of a peroxisomal-targeted aldolase involved in chlorophyll biosynthesis and sugar metabolism in rice.

PubMed

Zhang, Fei; Zhang, Pan; Zhang, Yu; Wang, Shouchuang; Qu, Lianghuan; Liu, Xianqing; Luo, Jie

2016-09-01

Chlorophyll plays remarkable and critical roles in photosynthetic light-harvesting, energy transduction and plant development. In this study, we identified a rice Chl-deficient mutant, ygdl-1 (yellow green and droopy leaf-1), which showed yellow-green leaves throughout plant development with decreased content of Chls and carotene and an increased Chl a/b ratio. The ygdl-1 mutant also exhibited severe defects in chloroplast development, including disorganized grana stacks. Sequence analysis revealed that the mutant contained a T-DNA insertion within the promoter of a fructose-1,6-bisphosphate aldolase (OsAld-Y), which dramatically reduced the OsAld-Y mRNA level, and its identity was verified by transgenic complementation. Real-time PCR analysis showed that the expression levels of genes associated with chlorophyll biosynthesis and chloroplast development were concurrently altered in the ygdl-1 mutant. The expression of OsAld-Y-GFP fusion protein in tobacco epidermal cells showed that OsAld-Y was localized to the peroxisome. In addition, the analysis of primary carbon metabolites revealed the significantly reduced levels of sucrose and fructose in the mutant leaves, while the glucose content was similar to wild-type plants. Our results suggest that the OsAld-Y participates in Chl accumulation, chloroplast development and plant growth by influencing the photosynthetic rate of leaves and the sugar metabolism of rice. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Zinc: physiology, deficiency, and parenteral nutrition.

PubMed

Livingstone, Callum

2015-06-01

The essential trace element zinc (Zn) has a large number of physiologic roles, in particular being required for growth and functioning of the immune system. Adaptive mechanisms enable the body to maintain normal total body Zn status over a wide range of intakes, but deficiency can occur because of reduced absorption or increased gastrointestinal losses. Deficiency impairs physiologic processes, leading to clinical consequences that include failure to thrive, skin rash, and impaired wound healing. Mild deficiency that is not clinically overt may still cause nonspecific consequences, such as susceptibility to infection and poor growth. The plasma Zn concentration has poor sensitivity and specificity as a test of deficiency. Consequently, diagnosis of deficiency requires a combination of clinical assessment and biochemical tests. Patients receiving parenteral nutrition (PN) are susceptible to Zn deficiency and its consequences. Nutrition support teams should have a strategy for assessing Zn status and optimizing this by appropriate supplementation. Nutrition guidelines recommend generous Zn provision from the start of PN. This review covers the physiology of Zn, the consequences of its deficiency, and the assessment of its status, before discussing its role in PN. © 2015 American Society for Parenteral and Enteral Nutrition.

Molecular dissection of the response of the rice Systemic Acquired Resistance Deficient 1 (SARD1) gene to different types of ionizing radiation.

PubMed

Jung, In Jung; Hwang, Jung Eun; Han, Sung Min; Kim, Dong Sub; Ahn, Joon-Woo; Choi, Hong-Il; Kwon, Soon-Jae; Kang, Si-Yong; Kim, Jin-Baek

2017-07-01

Exposure to ionizing radiation induces plant defenses by regulating the expression of response genes. The systemic acquired resistance deficient 1 (SARD1) is a key gene in plant defense response. In this study, the function of Oryza sativa SARD1 (OsSARD1) was investigated after exposure of seeds/plants to ionizing radiation, jasmonic acid (JA) or salicylic acid (SA). Rice seeds exposed to two types of ionizing radiations (gamma ray [GR] and ion beam [IB]) were analyzed by quantitative reverse transcription PCR (qRT-PCR) to identify the genes that are altered in response to ionizing radiation. Then, OsSARD1-overexpressing homozygous Arabidopsis plants were generated to assess the effects of OsSARD1 in the response to irradiation. The phenotypes of these transgenic plants, as well as control plants, were monitored after GR irradiation at doses of 200 and 300 Gray (Gy). The OsSARD1 transcript was strongly downregulated after exposure to GR and IB irradiation. Previous phylogenetic analysis showed that the Arabidopsis SARD1 (AtSARD1) protein is closely related to Arabidopsis calmodulin-binding protein 60g (AtCBP60g), which is known to be required for activation of SA biosynthesis. In this study, phylogenetic analysis showed that OsSARD1 was grouped with AtSARD1. The OsSARD1 gene was induced after exposure to SA and JA. The biological phenotype of OsSARD1-overexpressing Arabidopsis plants was examined. OsSARD1-overexpressing plants displayed resistance to GR; in comparison with wild-type plants, the height and weight of OsSARD1-overexpressing plants were significantly greater after GR irradiation. In addition, OsSARD1 protein was abundantly accumulated in the nucleus. The results indicate that OsSARD1 plays an important role in the regulation of the defense responses to GR and IB irradiation and exhibits phytohormone induced expression.

Dopamine alleviates nutrient deficiency-induced stress in Malus hupehensis.

PubMed

Liang, Bowen; Li, Cuiying; Ma, Changqing; Wei, Zhiwei; Wang, Qian; Huang, Dong; Chen, Qi; Li, Chao; Ma, Fengwang

2017-10-01

Dopamine mediates many physiological processes in plants. We investigated its role in regulating growth, root system architecture, nutrient uptake, and responses to nutrient deficiencies in Malus hupehensis Rehd. Under a nutrient deficiency, plants showed significant reductions in growth, chlorophyll concentrations, and net photosynthesis, along with disruptions in nutrient uptake, transport, and distribution. However, pretreatment with 100 μM dopamine markedly alleviated such inhibitions. Supplementation with that compound enabled plants to maintain their photosynthetic capacity and development of the root system while promoting the uptake of N, P, K, Ca, Mg, Fe, Mn, Cu, Zn, and B, altering the way in which those nutrients were partitioned throughout the plant. The addition of dopamine up-regulated genes for antioxidant enzymes involved in the ascorbate-glutathione cycle (MdcAPX, MdcGR, MdMDHAR, MdDHAR-1, and MdDHAR-2) but down-regulated genes for senescence (SAG12, PAO, and MdHXK). These results indicate that exogenous dopamine has an important antioxidant and anti-senescence effect that might be helpful for improving nutrient uptake. Our findings demonstrate that dopamine offers new opportunities for its use in agriculture, especially when addressing the problem of nutrient deficiencies. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Effect of bamboo and rice straw biochars on the mobility and redistribution of heavy metals (Cd, Cu, Pb and Zn) in contaminated soil.

PubMed

Lu, Kouping; Yang, Xing; Gielen, Gerty; Bolan, Nanthi; Ok, Yong Sik; Niazi, Nabeel Khan; Xu, Song; Yuan, Guodong; Chen, Xin; Zhang, Xiaokai; Liu, Dan; Song, Zhaoliang; Liu, Xingyuan; Wang, Hailong

2017-01-15

Biochar has emerged as an efficient tool to affect bioavailability of heavy metals in contaminated soils. Although partially understood, a carefully designed incubation experiment was performed to examine the effect of biochar on mobility and redistribution of Cd, Cu, Pb and Zn in a sandy loam soil collected from the surroundings of a copper smelter. Bamboo and rice straw biochars with different mesh sizes (<0.25 mm and <1 mm), were applied at three rates (0, 1, and 5% w/w). Heavy metal concentrations in pore water were determined after extraction with 0.01 M CaCl 2 . Phytoavailable metals were extracted using DTPA/TEA (pH 7.3). The European Union Bureau of Reference (EUBCR) sequential extraction procedure was adopted to determine metal partitioning and redistribution of heavy metals. Results showed that CaCl 2 -and DTPA-extractable Cd, Cu, Pb and Zn concentrations were significantly (p < 0.05) lower in the bamboo and rice straw biochar treated soils, especially at 5% application rate, than those in the unamended soil. Soil pH values were significantly correlated with CaCl 2 -extractable metal concentrations (p < 0.01). The EUBCR sequential extraction procedure revealed that the acid extractable fractions of Cd, Cu, Pb and Zn decreased significantly (p < 0.05) with biochar addition. Rice straw biochar was more effective than bamboo biochar in decreasing the acid extractable metal fractions, and the effect was more pronounced with increasing biochar application rate. The effect of biochar particle size on extractable metal concentrations was not consistent. The 5% rice straw biochar treatment reduced the DTPA-extractable metal concentrations in the order of Cd < Cu < Pb < Zn, and reduced the acid extractable pool of Cd, Cu, Pb and Zn by 11, 17, 34 and 6%, respectively, compared to the control. In the same 5% rice straw biochar treatments, the organic bound fraction increased by 37, 58, 68 and 18% for Cd, Cu, Pb and Zn, respectively, compared to the control, indicating that the immobilized metals were mainly bound in the soil organic matter fraction. The results demonstrated that the rice straw biochar can effectively immobilize heavy metals, thereby reducing their mobility and bioavailability in contaminated soils. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Role of a Potassium Transporter OsHAK5 in Potassium Acquisition and Transport from Roots to Shoots in Rice at Low Potassium Supply Levels1[W][OPEN

PubMed Central

Yang, Tianyuan; Zhang, Song; Hu, Yibing; Wu, Fachi; Hu, Qingdi; Chen, Guang; Cai, Jing; Wu, Ting; Moran, Nava; Yu, Ling; Xu, Guohua

2014-01-01

In plants, K transporter (KT)/high affinity K transporter (HAK)/K uptake permease (KUP) is the largest potassium (K) transporter family; however, few of the members have had their physiological functions characterized in planta. Here, we studied OsHAK5 of the KT/HAK/KUP family in rice (Oryza sativa). We determined its cellular and tissue localization and analyzed its functions in rice using both OsHAK5 knockout mutants and overexpression lines in three genetic backgrounds. A β-glucuronidase reporter driven by the OsHAK5 native promoter indicated OsHAK5 expression in various tissue organs from root to seed, abundantly in root epidermis and stele, the vascular tissues, and mesophyll cells. Net K influx rate in roots and K transport from roots to aerial parts were severely impaired by OsHAK5 knockout but increased by OsHAK5 overexpression in 0.1 and 0.3 mm K external solution. The contribution of OsHAK5 to K mobilization within the rice plant was confirmed further by the change of K concentration in the xylem sap and K distribution in the transgenic lines when K was removed completely from the external solution. Overexpression of OsHAK5 increased the K-sodium concentration ratio in the shoots and salt stress tolerance (shoot growth), while knockout of OsHAK5 decreased the K-sodium concentration ratio in the shoots, resulting in sensitivity to salt stress. Taken together, these results demonstrate that OsHAK5 plays a major role in K acquisition by roots faced with low external K and in K upward transport from roots to shoots in K-deficient rice plants. PMID:25157029

Examining the specific contributions of individual Arabidopsis metallothioneins to copper distribution and metal tolerance.

PubMed

Guo, Woei-Jiun; Meetam, Metha; Goldsbrough, Peter B

2008-04-01

Metallothioneins (MTs) are small cysteine-rich proteins found in various eukaryotes. Plant MTs are classified into four types based on the arrangement of cysteine residues. To determine whether all four types of plant MTs function as metal chelators, six Arabidopsis (Arabidopsis thaliana) MTs (MT1a, MT2a, MT2b, MT3, MT4a, and MT4b) were expressed in the copper (Cu)- and zinc (Zn)-sensitive yeast mutants, Deltacup1 and Deltazrc1 Deltacot1, respectively. All four types of Arabidopsis MTs provided similar levels of Cu tolerance and accumulation to the Deltacup1 mutant. The type-4 MTs (MT4a and MT4b) conferred greater Zn tolerance and higher accumulation of Zn than other MTs to the Deltazrc1 Deltacot1 mutant. To examine the functions of MTs in plants, we studied Arabidopsis plants that lack MT1a and MT2b, two MTs that are expressed in phloem. The lack of MT1a, but not MT2b, led to a 30% decrease in Cu accumulation in roots of plants exposed to 30 mum CuSO(4). Ectopic expression of MT1a RNA in the mt1a-2 mt2b-1 mutant restored Cu accumulation in roots. The mt1a-2 mt2b-1 mutant had normal metal tolerance. However, when MT deficiency was combined with phytochelatin deficiency, growth of the mt1a-2 mt2b-1 cad1-3 triple mutant was more sensitive to Cu and cadmium compared to the cad1-3 mutant. Together these results provide direct evidence for functional contributions of MTs to plant metal homeostasis. MT1a, in particular, plays a role in Cu homeostasis in the roots under elevated Cu. Moreover, MTs and phytochelatins function cooperatively to protect plants from Cu and cadmium toxicity.

Temporal interactions of plant - insect - predator after infection of bacterial pathogen on rice plants.

PubMed

Sun, Ze; Liu, Zhuang; Zhou, Wen; Jin, Huanan; Liu, Hao; Zhou, Aiming; Zhang, Aijun; Wang, Man-Qun

2016-05-17

Pathogenic infection on plants may affect interactions of host-plants with their herbivores, as well as the herbivores with their predators. In this study, the effects of infection by pathogenic bacterium Xanthomonas oryzae pv. oryzae (Xoo), which causes a vascular disease in rice, on rice plants and consequent interactions with a rice herbivore, brown rice planthopper (BPH) Nilaparvata lugens, and its major predator, Cyrtorhinus lividipennis, were investigated. The results showed that the rice plants exhibited increased resistance to BPH only at 3 d post-inoculation of Xoo, while the Xoo infection did not affect the development and fecundity of BPH. BPH exhibited a higher preference to Xoo infected rice plants, whereas C. lividipennis preferred the Xoo infected rice plants after BPH fed, but preferred healthy rice plants without BPH fed. Volatile organic compounds emitted from Xoo rice were significantly higher than those from healthy rice plants, Xoo infection on BPH fed plants caused rice plants to emit more the herbivore-induced plant volatiles, while all of these changes correlated to the temporal dimension. These results demonstrated that Xoo infection significantly influenced the interactions of rice plants with two non-vectors, BPH and its predator, although these effects exhibited in a temporal pattern after infection.

Ecological occurrence of Gluconacetobacter diazotrophicus and nitrogen-fixing Acetobacteraceae members: their possible role in plant growth promotion.

PubMed

Saravanan, V S; Madhaiyan, M; Osborne, Jabez; Thangaraju, M; Sa, T M

2008-01-01

Gluconacetobacter diazotrophicus has a long-standing history of bacterial-plant interrelationship as a symbiotic endophyte capable of fixing atmospheric nitrogen. In low nitrogen fertilized sugarcane fields it plays a significant role and its occurrence was realised in most of the sugarcane growing countries. In this mini review, the association of G. diazotrophicus with sugarcane, other crop plants and with various hosts is discussed. The factors affecting survival in the rhizosphere and the putative soil mode of transmission are emphasized. In addition, other N(2)-fixing Acetobacteraceae members, including Gluconacetobacter azotocaptans, Gluconacetobacter johannae and Swaminathania salitolerans, occurring in coffee, corn and rice plants are also covered. Lastly, the plant-growth-promoting traits identified in this group of bacteria, including N(2) fixation, phytohormone synthesis, P and Zn solubilization and biocontrol, are analysed.

Stabilization of lead (Pb) and zinc (Zn) in contaminated rice paddy soil using starfish: A preliminary study.

PubMed

Moon, Deok Hyun; Hwang, Inseong; Koutsospyros, Agamemnon; Cheong, Kyung Hoon; Ok, Yong Sik; Ji, Won Hyun; Park, Jeong-Hun

2018-05-01

Lead (Pb) and zinc (Zn) contaminated rice paddy soil was stabilized using natural (NSF) and calcined starfish (CSF). Contaminated soil was treated with NSF in the range of 0-10 wt% and CSF in the range of 0-5 wt% and cured for 28 days. Toxicity characteristic leaching procedure (TCLP) test was used to evaluate effectiveness of starfish treatment. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX) analyses were conducted to investigate the mechanism responsible for effective immobilization of Pb and Zn. Experimental results suggest that NSF and CSF treatments effectively immobilize Pb and Zn in treated rice paddy soil. TCLP levels for Pb and Zn were reduced with increasing NSF and CSF dosage. Comparison of the two treatment methods reveals that CSF treatment is more effective than NSF treatment. Leachability of the two metals is reduced approximately 58% for Pb and 51% for Zn, upon 10 wt% NSF treatment. More pronounced leachability reductions, 93% for Pb and 76% for Zn, are achieved upon treatment with 5 wt% CSF. Sequential extraction results reveal that NSF and CSF treatments of contaminated soil generated decrease in exchangeable/weak acid Pb and Zn soluble fractions, and increase of residual Pb and Zn fractions. Results for the SEM-EDX sample treated with 5 wt% CSF indicate that effective Pb and Zn immobilization is most probably associated with calcium silicate hydrates (CSHs) and calcium aluminum hydrates (CAHs). Copyright © 2018 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taha, Mohd F., E-mail: faisalt@petronas.com.my; Shaharun, Maizatul S.; Shuib, Anis Suhaila, E-mail: anisuha@petronas.com.my

An attempt was made to investigate the potential of rice husk-based activated carbon as an alternative low-cost adsorbent for the removal of Ni(II), Zn(II) and Pb(II) ions from single aqueous solution. Rice husk-based activated carbon was prepared via treatment of rice husk with NaOH followed by the carbonization process at 400°C for 2 hours. Three samples, i.e. raw rice husk, rice husk treated with NaOH and rice husk-based activated carbon, were analyzed for their morphological characteristics using field-emission scanning electron microscope/energy dispersive X-ray (FESEM/EDX). These samples were also analyzed for their carbon, hydrogen, nitrogen, oxygen and silica contents using CHNmore » elemental analyzer and FESEM/EDX. The porous properties of rice husk-based activated carbon were determined by Brunauer-Emmett-Teller (BET) surface area analyzer, and its surface area and pore volume were 255 m{sup 2}/g and 0.17 cm{sup 2}/g, respectively. The adsorption studies for the removal of Ni(II), Zn(II) and Pb(II) ions from single metal aqueous solution were carried out at a fixed initial concentration of metal ion (150 ppm) with variation amount of adsorbent (rice husk-based activated carbon) as a function of varied contact time at room temperature. The concentration of each metal ion was analyzed using atomic absorption spectrophotometer (AAS). The results obtained from adsorption studies indicate the potential of rice husk as an economically promising precursor for the preparation of activated carbon for removal of Ni(II), Zn(II) and Pb(II) ions from single aqueous solution. Isotherm and kinetic model analyses suggested that the experimental data of adsorption studies fitted well with Langmuir, Freundlich and second-order kinetic models.« less

Isoflurane anesthesia exacerbates learning and memory impairment in zinc-deficient APP/PS1 transgenic mice.

PubMed

Feng, Chunsheng; Liu, Ya; Yuan, Ye; Cui, Weiwei; Zheng, Feng; Ma, Yuan; Piao, Meihua

2016-12-01

Zinc (Zn) is known to play crucial roles in numerous brain functions including learning and memory. Zn deficiency is believed to be widespread throughout the world, particularly in patients with Alzheimer's disease (AD). A number of studies have shown that volatile anesthetics, such as isoflurane, might be potential risk factors for the development of AD. However, whether isoflurane exposure accelerates the process of AD and cognitive impairment in AD patients with Zn deficiency is yet to be documented. The aim of the present study was to explore the effects of 1.4% isoflurane exposure for 2 h on learning and memory function, and neuropathogenesis in 10-month-old Zn-adequate, Zn-deficient, and Zn-treated APP/PS1 mice with the following parameters: behavioral tests, neuronal apoptosis, Aβ, and tau pathology. The results demonstrated that isoflurane exposure showed no impact on learning and memory function, but induced transient elevation of neuroapoptosis in Zn-adequate APP/PS1 mice. Exposure of isoflurane exhibited significant neuroapoptosis, Aβ generation, tau phosphorylation, and learning and memory impairment in APP/PS1 mice in the presence of Zn deficiency. Appropriate Zn treatment improved learning and memory function, and prevented isoflurane-induced neuroapoptosis in APP/PS1 mice. Isoflurane exposure may cause potential neurotoxicity, which is tolerated to some extent in Zn-adequate APP/PS1 mice. When this tolerance is limited, like in AD with Zn deficiency, isoflurane exposure markedly exacerbated learning and memory impairment, and neuropathology, indicating that AD patients with certain conditions such as Zn deficiency may be vulnerable to volatile anesthetic isoflurane. Copyright © 2016 Elsevier Ltd. All rights reserved.

One-pot green synthesis of zinc oxide nano rice and its application as sonocatalyst for degradation of organic dye and synthesis of 2-benzimidazole derivatives

NASA Astrophysics Data System (ADS)

Paul, Bappi; Vadivel, Sethumathavan; Dhar, Siddhartha Sankar; Debbarma, Shyama; Kumaravel, M.

2017-05-01

In this paper, we report novel and green approach for one-pot biosynthesis of zinc oxide (ZnO) nanoparticles (NPs). Highly stable and hexagonal phase ZnO nanoparticles were synthesized using seeds extract from the tender pods of Parkia roxburghii and characterized by XRD, FT-IR, EDX, TEM, and N2 adsorption-desorption (BET) studies. The present method of synthesis of ZnO NPs is very efficient and cost effective. The powder XRD pattern furnished evidence for the formation of hexagonal close packing structure of ZnO NPs having average crystallite size 25.6 nm. The TEM image reveals rice shapes ZnO NPs are with an average diameter of 40-60 nm. The as-synthesized ZnO NPs has proved to be an excellent sonocatalysts for degradation of organic dye and synthesis of 2-benzimidazole derivatives.

Phosphorus uptake, partitioning and redistribution during grain filling in rice.

PubMed

Julia, Cécile; Wissuwa, Matthias; Kretzschmar, Tobias; Jeong, Kwanho; Rose, Terry

2016-11-01

In cultivated rice, phosphorus (P) in grains originates from two possible sources, namely exogenous (post-flowering root P uptake from soil) or endogenous (P remobilization from vegetative parts) sources. This study investigates P partitioning and remobilization in rice plants throughout grain filling to resolve contributions of P sources to grain P levels in rice. Rice plants (Oryza sativa 'IR64') were grown under P-sufficient or P-deficient conditions in the field and in hydroponics. Post-flowering uptake, partitioning and re-partitioning of P was investigated by quantifying tissue P levels over the grain filling period in the field conditions, and by employing 33 P isotope as a tracer in the hydroponic study. Post-flowering P uptake represented 40-70 % of the aerial plant P accumulation at maturity. The panicle was the main P sink in all studies, and the amount of P potentially remobilized from vegetative tissues to the panicle during grain filling was around 20 % of the total aerial P measured at flowering. In hydroponics, less than 20 % of the P tracer taken up at 9 d after flowering (DAF) was found in the above-ground tissues at 14 DAF and half of it was partitioned to the panicle in both P treatments. The results demonstrate that P uptake from the soil during grain filling is a critical contributor to the P content in grains in irrigated rice. The P tracer study suggests that the mechanism of P loading into grains involves little direct transfer of post-flowering P uptake to the grain but rather substantial mobilization of P that was previously taken up and stored in vegetative tissues. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Foliar application with nano-silicon reduced cadmium accumulation in grains by inhibiting cadmium translocation in rice plants.

PubMed

Chen, Rui; Zhang, Changbo; Zhao, Yanling; Huang, Yongchun; Liu, Zhongqi

2018-01-01

Nano-silicon (Si) may be more effective than regular fertilizers in protecting plants from cadmium (Cd) stress. A field experiment was conducted to study the effects of nano-Si on Cd accumulation in grains and other organs of rice plants (Oryza sativa L. cv. Xiangzaoxian 45) grown in Cd-contaminated farmland. Foliar application with 5~25 mM nano-Si at anthesis stage reduced Cd concentrations in grains and rachises at maturity stage by 31.6~64.9 and 36.1~60.8%, respectively. Meanwhile, nano-Si application significantly increased concentrations of potassium (K), magnesium (Mg), and iron (Fe) in grains and rachises, but imposed little effect on concentrations of calcium (Ca), zinc (Zn), and manganese (Mn) in them. Uppermost nodes under panicles displayed much higher Cd concentration (4.50~5.53 mg kg -1 ) than other aerial organs. After foliar application with nano-Si, translocation factors (TFs) of Cd ions from the uppermost nodes to rachises significantly declined, but TFs of K, Mg, and Fe from the uppermost nodes to rachises increased significantly. High dose of nano-Si (25 mM) was more effective than low dose of nano-Si in reducing TFs of Cd from roots to the uppermost nodes and from the uppermost nodes to rachises. These findings indicate that nano-Si supply reduces Cd accumulation in grains by inhibiting translocation of Cd and, meanwhile, promoting translocation of K, Mg, and Fe from the uppermost nodes to rachises in rice plants.

Analysis of Metal Element Distributions in Rice (Oryza sativa L.) Seeds and Relocation during Germination Based on X-Ray Fluorescence Imaging of Zn, Fe, K, Ca, and Mn

PubMed Central

Lu, Lingli; Tian, Shengke; Liao, Haibing; Zhang, Jie; Yang, Xiaoe; Labavitch, John M.; Chen, Wenrong

2013-01-01

Knowledge of mineral localization within rice grains is important for understanding the role of different elements in seed development, as well as for facilitating biofortification of seed micronutrients in order to enhance seeds’ values in human diets. In this study, the concentrations of minerals in whole rice grains, hulls, brown rice, bran and polished rice were quantified by inductively coupled plasma mass spectroscopy. The in vivo mineral distribution patterns in rice grains and shifts in those distribution patterns during progressive stages of germination were analyzed by synchrotron X-ray microfluorescence. The results showed that half of the total Zn, two thirds of the total Fe, and most of the total K, Ca and Mn were removed by the milling process if the hull and bran were thoroughly polished. Concentrations of all elements were high in the embryo regions even though the local distributions within the embryo varied between elements. Mobilization of the minerals from specific seed locations during germination was also element-specific. High mobilization of K and Ca from grains to growing roots and leaf primordia was observed; the flux of Zn to these expanding tissues was somewhat less than that of K and Ca; the mobilization of Mn or Fe was relatively low, at least during the first few days of germination. PMID:23451212

Potential for phytoextraction of copper, lead, and zinc by rice (Oryza sativa L.), soybean (Glycine max [L.] Merr.), and maize (Zea mays L.).

PubMed

Murakami, Masaharu; Ae, Noriharu

2009-03-15

Phytoextraction by hyperaccumulators has been proposed for decreasing toxic-metal concentrations of contaminated soils. However, hyperaccumulators have several shortcomings to introduce these species into Asian Monsoon's agricultural fields contaminated with low to moderate toxic-metals. To evaluate the phytoextraction potential, maize (Gold Dent), soybean (Enrei and Suzuyutaka), and rice (Nipponbare and Milyang 23) were pot-grown under aerobic soil conditions for 60d on the Andosol or Fluvisol with low to moderate copper (Cu), lead (Pb), and zinc (Zn) contamination. After 2 months cultivation, the Gold Dent maize and Milyang 23 rice shoots took up 20.2-29.5% and 18.5-20.2% of the 0.1molL(-1) HCl-extractable Cu, 10.0-37.3% and 8.5-34.3% of the DTPA-extractable Cu, and 2.4-6.5% and 2.1-5.9% of the total Cu, respectively, in the two soils. Suzuyutaka soybean shoot took up 23.0-29.4% of the 0.1molL(-1) HCl-extractable Zn, 35.1-52.6% of the DTPA-extractable Zn, and 3.8-5.3% of the total Zn in the two soils. Therefore, there is a great potential for Cu phytoextraction by the Gold Dent maize and the Milyang 23 rice and for Zn phytoextraction by the Suzuyutaka soybean from paddy soils with low to moderate contamination under aerobic soil conditions.

Chronic zinc deficiency alters chick gut microbiota composition and function

USDA-ARS?s Scientific Manuscript database

Zinc (Zn) deficiency is a prevalent micronutrient insufficiency. Although the gut is a vital organ for Zn utilization, and Zn deficiency is associated with impaired intestinal permeability and a global decrease in gastrointestinal health, alterations in the gut microbial ecology of the host under co...

Micronutrients in Soils, Crops, and Livestock

NASA Astrophysics Data System (ADS)

Gupta, Umesh C.; Wu, Kening; Liang, Siyuan

Micronutrient concentrations are generally higher in the surface soil and decrease with soil depth. In spite of the high concentration of most micronutrients in soils, only a small fraction is available to plants. Micronutrients, also known as trace elements, are required in microquantities but their lack can cause serious crop production and animal health problems. Crops vary considerably in their response to various micronutrients. Brassicas and legumes are highly responsive to molybdenum (Mo) and boron (B), whereas corn and other cereals are more responsive to zinc (Zn) and copper (Cu). Micronutrient deficiencies are more common in humid temperate regions, as well as in humid tropical regions, because of intense leaching associated with high precipitation. Soil pH is one of the most important factors affecting the availability of micronutrients to plants. With increasing pH, the availability of these nutrients is reduced with the exception of Mo whose availability increases as soil pH increases. In most plant species, leaves contain higher amounts of nutrients than other plant parts. Therefore, whenever possible, leaves should be sampled to characterize the micronutrient status of crops. Deficiency symptoms for most micronutrients appear on the younger leaves at the top of the plant, whereas toxicity symptoms generally appear on the older leaves of plants. As summarized by Deckers and Steinnes, micronutrient deficiencies are widespread in developing countries, which have much poorer soil resources than the fertile soils of Europe and North America. Many of these areas lie in the humid tropics with extremely infertile, highly weathered, and/or highly leached soils, which are intensely deficient in nutrients. The rest of such soils are in the semiarid and areas adjacent to the latter, where alkaline and calcareous soil conditions severely limit the availability of micronutrients to plants. Frequently, the Cu, iron (Fe), manganese (Mn), Zn, and selenium (Se) levels in forages, which are sufficient for optimum crop yields, are not adequate to meet the needs of livestock. Selenium is a trace mineral, which is not required by plants, and maximum forage yields can be obtained on soils with very low amounts of soil Se. However, if animals are fed feed crops and forages with low Se, they could suffer from serious muscular disorders and other diseases. White muscle disease caused by Se deficiency is the most common disorder and is found in calves and lambs. Sufficiency levels of micronutrients for crops have been discussed in relation to the animal requirement.

OsSLI1, a homeodomain containing transcription activator, involves abscisic acid related stress response in rice (Oryza sativa L.).

PubMed

Huang, Xi; Duan, Min; Liao, Jiakai; Yuan, Xi; Chen, Hui; Feng, Jiejie; Huang, Ji; Zhang, Hong-Sheng

2014-01-01

Homeodomain-leucine zipper type I (HD-Zip I) proteins are involved in the regulation of plant development and response to environmental stresses. In this study, OsSLI1 (Oryza sativa stress largely induced 1), encoding a member of the HD-Zip I subfamily, was isolated from rice. The expression of OsSLI1 was dramatically induced by multiple abiotic stresses and exogenous abscisic acid (ABA). In silico sequence analysis discovered several cis-acting elements including multiple ABREs (ABA-responsive element binding factors) in the upstream promoter region of OsSLI1. The OsSLI1-GFP fusion protein was localized in the nucleus of rice protoplast cells and the transcriptional activity of OsSLI1 was confirmed by the yeast hybrid system. Further, it was found that OsSLI1 expression was enhanced in an ABI5-Like1 (ABL1) deficiency rice mutant abl1 under stress conditions, suggesting that ABL1 probably negatively regulates OsSLI1 gene expression. Moreover, it was found that OsSLI1 was regulated in panicle development. Taken together, OsSLI1 may be a transcriptional activator regulating stress-responsive gene expression and panicle development in rice.

Comparative in Silico Analysis of Ferric Reduction Oxidase (FRO) Genes Expression Patterns in Response to Abiotic Stresses, Metal and Hormone Applications.

PubMed

Muhammad, Izhar; Jing, Xiu-Qing; Shalmani, Abdullah; Ali, Muhammad; Yi, Shi; Gan, Peng-Fei; Li, Wen-Qiang; Liu, Wen-Ting; Chen, Kun-Ming

2018-05-12

The ferric reduction oxidase (FRO) gene family is involved in various biological processes widely found in plants and may play an essential role in metal homeostasis, tolerance and intricate signaling networks in response to a number of abiotic stresses. Our study describes the identification, characterization and evolutionary relationships of FRO genes families. Here, total 50 FRO genes in Plantae and 15 ‘FRO like’ genes in non-Plantae were retrieved from 16 different species. The entire FRO genes have been divided into seven clades according to close similarity in biological and functional behavior. Three conserved domains were common in FRO genes while in two FROs sub genome have an extra NADPH-Ox domain, separating the function of plant FROs. OsFRO1 and OsFRO7 genes were expressed constitutively in rice plant. Real-time RT-PCR analysis demonstrated that the expression of OsFRO1 was high in flag leaf, and OsFRO7 gene expression was maximum in leaf blade and flag leaf. Both genes showed vigorous expressions level in response to different abiotic and hormones treatments. Moreover, the expression of both genes was also substantial under heavy metal stresses. OsFRO1 gene expression was triggered following 6 h under Zn, Pb, Co and Ni treatments, whereas OsFRO7 gene expression under Fe, Pb and Ni after 12 h, Zn and Cr after 6 h, and Mn and Co after 3 h treatments. These findings suggest the possible involvement of both the genes under abiotic and metal stress and the regulation of phytohormones. Therefore, our current work may provide the foundation for further functional characterization of rice FRO genes family.

Belowground Inoculation With Arbuscular Mycorrhizal Fungi Increases Local and Systemic Susceptibility of Rice Plants to Different Pest Organisms

PubMed Central

Bernaola, Lina; Cosme, Marco; Schneider, Raymond W.; Stout, Michael

2018-01-01

Plants face numerous challenges from both aboveground and belowground stressors, and defend themselves against harmful insects and microorganisms in many ways. Because plant responses to biotic stresses are not only local but also systemic, belowground interactions can influence aboveground interactions in both natural and agricultural ecosystems. Arbuscular mycorrhizal fungi (AMF) are soilborne organisms that form symbiotic associations with many plant roots and are thought to play a central role in plant nutrition, growth, and fitness. In the present study, we focused on the influence of AMF on rice defense against pests. We inoculated rice plants with AMF in several field and greenhouse experiments to test whether the interaction of AMF with rice roots changes the resistance of rice against two chewing insects, the rice water weevil (Lissorhoptrus oryzophilus Kuschel, RWW) and the fall armyworm (Spodoptera frugiperda, FAW), and against infection by sheath blight (Rhizoctonia solani, ShB). Both in field and greenhouse experiments, the performance of insects and the pathogen on rice was enhanced when plants were inoculated with AMF. In the field, inoculating rice plants with AMF resulted in higher numbers of RWW larvae on rice roots. In the greenhouse, more RWW first instars emerged from AMF-colonized rice plants than from non-colonized control plants. Weight gains of FAW larvae were higher on rice plants treated with AMF inoculum. Lesion lengths and susceptibility to ShB infection were higher in rice plants colonized by AMF. Although AMF inoculation enhanced the growth of rice plants, the nutritional analyses of root and shoot tissues indicated no major increases in the concentrations of nutrients in rice plants colonized by AMF. The large effects on rice susceptibility to pests in the absence of large effects on plant nutrition suggest that AMF colonization influences other mechanisms of susceptibility (e.g., defense signaling processes). This study represents the first study conducted in the U.S. in rice showing AMF-induced plant susceptibility to several antagonists that specialize on different plant tissues. Given the widespread occurrence of AMF, our findings will help to provide a different perspective into the causal basis of rice systemic resistance/susceptibility to insects and pathogens. PMID:29922319

Belowground Inoculation With Arbuscular Mycorrhizal Fungi Increases Local and Systemic Susceptibility of Rice Plants to Different Pest Organisms.

PubMed

Bernaola, Lina; Cosme, Marco; Schneider, Raymond W; Stout, Michael

2018-01-01

Plants face numerous challenges from both aboveground and belowground stressors, and defend themselves against harmful insects and microorganisms in many ways. Because plant responses to biotic stresses are not only local but also systemic, belowground interactions can influence aboveground interactions in both natural and agricultural ecosystems. Arbuscular mycorrhizal fungi (AMF) are soilborne organisms that form symbiotic associations with many plant roots and are thought to play a central role in plant nutrition, growth, and fitness. In the present study, we focused on the influence of AMF on rice defense against pests. We inoculated rice plants with AMF in several field and greenhouse experiments to test whether the interaction of AMF with rice roots changes the resistance of rice against two chewing insects, the rice water weevil ( Lissorhoptrus oryzophilus Kuschel, RWW) and the fall armyworm ( Spodoptera frugiperda , FAW), and against infection by sheath blight ( Rhizoctonia solani , ShB). Both in field and greenhouse experiments, the performance of insects and the pathogen on rice was enhanced when plants were inoculated with AMF. In the field, inoculating rice plants with AMF resulted in higher numbers of RWW larvae on rice roots. In the greenhouse, more RWW first instars emerged from AMF-colonized rice plants than from non-colonized control plants. Weight gains of FAW larvae were higher on rice plants treated with AMF inoculum. Lesion lengths and susceptibility to ShB infection were higher in rice plants colonized by AMF. Although AMF inoculation enhanced the growth of rice plants, the nutritional analyses of root and shoot tissues indicated no major increases in the concentrations of nutrients in rice plants colonized by AMF. The large effects on rice susceptibility to pests in the absence of large effects on plant nutrition suggest that AMF colonization influences other mechanisms of susceptibility (e.g., defense signaling processes). This study represents the first study conducted in the U.S. in rice showing AMF-induced plant susceptibility to several antagonists that specialize on different plant tissues. Given the widespread occurrence of AMF, our findings will help to provide a different perspective into the causal basis of rice systemic resistance/susceptibility to insects and pathogens.

Distribution and migration of heavy metals in soil and crops affected by acid mine drainage: Public health implications in Guangdong Province, China.

PubMed

Liao, Jianbo; Wen, Zewei; Ru, Xuan; Chen, Jundong; Wu, Haizhen; Wei, Chaohai

2016-02-01

Acid mine drainages (AMD) contain high concentrations of heavy metals, and their discharges into streams and rivers constitute serious environmental problems. This article examines the effects of AMD on soil, plant and human health at Dabaoshan mine in Guangdong Province, China. Although the large scale mining was stopped in 2011, the heavy metal pollution in soil continues to endanger crops and human health in that region. The objectives of this study were to elucidate distribution and migration of Cd, Cu, Zn, As and Pb and associated health implications to local inhabitants. We collected and analyzed 74 crop samples including 28 sugarcane, 30 vegetables, 16 paddy rice and the corresponding soil samples, used correlation and linear relationship for transformation process analysis, and applied carcinogenic and non-carcinogenic risk for hazard evaluation. Results showed that the local soils were heavily polluted with Cd, Cu and As (especially for Cd) and the mean Igeo value was as high as 3.77. Cadmium, Cu, and Zn in rice and vegetables were comparable with those found four years ago, while As and Pb in edible parts were 2 to 5 times lower than before. The root uptake of Cd and Zn contributed mainly to their high concentrations in crops due to high exchangeable fraction of soil, while leafy vegetables accumulated elevated As and Pb contents mainly due to the atmospheric deposition. Metal concentrations in sugarcane roots were higher than those in rice and vegetable roots. The risk assessment for crops consumption showed that the hazard quotients values were of 21 to 25 times higher than the threshold level for vegetables and rice, indicating a potential non-carcinogenic risk to the consumers. The estimated mean total cancer risk value of 0.0516 more than 100 times exceeded the USEPA accepted risk level of 1×10(-4), indicating unsuitability of the soil for cultivating the food crops. Therefore, the local agricultural and the land-use policies need to be reevaluated. Copyright © 2015 Elsevier Inc. All rights reserved.

Effects of Slag-Based Silicon Fertilizer on Rice Growth and Brown-Spot Resistance

PubMed Central

Ning, Dongfeng; Song, Alin; Fan, Fenliang; Li, Zhaojun; Liang, Yongchao

2014-01-01

It is well documented that slag-based silicon fertilizers have beneficial effects on the growth and disease resistance of rice. However, their effects vary greatly with sources of slag and are closely related to availability of silicon (Si) in these materials. To date, few researches have been done to compare the differences in plant performance and disease resistance between different slag-based silicon fertilizers applied at the same rate of plant-available Si. In the present study both steel and iron slags were chosen to investigate their effects on rice growth and disease resistance under greenhouse conditions. Both scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to examine the effects of slags on ultrastructural changes in leaves of rice naturally infected by Bipolaris oryaze, the causal agent of brown spot. The results showed that both slag-based Si fertilizers tested significantly increased rice growth and yield, but decreased brown spot incidence, with steel slag showing a stronger effect than iron slag. The results of SEM analysis showed that application of slags led to more pronounced cell silicification in rice leaves, more silica cells, and more pronounced and larger papilla as well. The results of TEM analysis showed that mesophyll cells of slag-untreated rice leaf were disorganized, with colonization of the fungus (Bipolaris oryzae), including chloroplast degradation and cell wall alterations. The application of slag maintained mesophyll cells relatively intact and increased the thickness of silicon layer. It can be concluded that applying slag-based fertilizer to Si-deficient paddy soil is necessary for improving both rice productivity and brown spot resistance. The immobile silicon deposited in host cell walls and papillae sites is the first physical barrier for fungal penetration, while the soluble Si in the cytoplasm enhances physiological or induced resistance to fungal colonization. PMID:25036893

Overexpression of miR169o, an Overlapping microRNA in Response to Both Nitrogen Limitation and Bacterial Infection, Promotes Nitrogen Use Efficiency and Susceptibility to Bacterial Blight in Rice.

PubMed

Chao, Yu; Chen, Yutong; Cao, Yaqian; Chen, Huamin; Wang, Jichun; Bi, Yong-Mei; Tian, Fang; Yang, Fenghuan; Rothstein, Steven J; Zhou, Xueping; He, Chenyang

2018-03-15

Limiting nitrogen (N) supply contributes to improved resistance to bacterial blight (BB) caused by Xanthomonas oryzae pv. oryzae (Xoo) in susceptible rice (Oryza sativa). To understand the regulatory roles of microRNAs in this phenomenon, sixty-three differentially-expressed overlapping miRNAs in response to Xoo infection and N-limitation stress in rice were identified through deep RNA-sequence and stem loop qRT-PCR. Among these, miR169o was further assessed as a typical overlapping miRNA through the overexpression of the miR169o primary gene. Osa-miR169o-OX plants were taller, and had more biomass accumulation with significantly increased nitrate and total amino acid contents in roots than wild type (WT). Transcript level assays showed that under different N supply conditions miR169o opposite regulated NRT2 which is reduced under normal N supply condition but remarkably induced under N limiting stress. On the other hand, osa-miR169o-OX plants also displayed increased disease lesion lengths and reduced transcriptional levels of defense gene (PR1b, PR10a, PR10b and PAL) compared with WT after inoculation with Xoo. In addition, miR169o impeded Xoo-mediated NRT transcription. Therefore, the overlapping miR169o contributes to increase N use efficiency and negatively regulates the resistance to bacterial blight in rice. Consistently, transient expression of NF-YAs in rice protoplast promoted the transcripts of PR genes and NRT2 genes, while reduced the transcripts of NRT1 genes. Our results provide novel and additional insights into the coordinated regulatory mechanisms of crosstalk between Xoo infection and N-deficiency responses in rice.

Cryptochrome and Phytochrome Cooperatively but Independently Reduce Active Gibberellin Content in Rice Seedlings under Light Irradiation

PubMed Central

Hirose, Fumiaki; Inagaki, Noritoshi; Hanada, Atsushi; Yamaguchi, Shinjiro; Kamiya, Yuji; Miyao, Akio; Hirochika, Hirohiko; Takano, Makoto

2012-01-01

In contrast to a wealth of knowledge about the photoregulation of gibberellin metabolism in dicots, that in monocots remains largely unclear. In this study, we found that a blue light signal triggers reduction of active gibberellin content in rice seedlings with simultaneous repression of two gibberellin 20-oxidase genes (OsGA20ox2 and OsGA20ox4) and acute induction of four gibberellin 2-oxidase genes (OsGA2ox4–OsGA2ox7). For further examination of the regulation of these genes, we established a series of cryptochrome-deficient lines through reverse genetic screening from a Tos17 mutant population and construction of knockdown lines based on an RNA interference technique. By using these lines and phytochrome mutants, we elucidated that cryptochrome 1 (cry1), consisting of two species in rice plants (cry1a and cry1b), is indispensable for robust induction of the GA2ox genes. On the other hand, repression of the GA20ox genes is mediated by phytochromes. In addition, we found that the phytochromes also mediate the repression of a gibberellin 3-oxidase gene (OsGA3ox2) in the light. These results imply that, in rice seedlings, phytochromes mediate the repression of gibberellin biosynthesis capacity, while cry1 mediates the induction of gibberellin inactivation capacity. The cry1 action was demonstrated to be dominant in the reduction of active gibberellin content, but, in rice seedlings, the cumulative effects of these independent actions reduced active gibberellin content in the light. This pathway design in which different types of photoreceptors independently but cooperatively regulate active gibberellin content is unique from the viewpoint of dicot research. This redundancy should provide robustness to the response in rice plants. PMID:22764280

Cryptochrome and phytochrome cooperatively but independently reduce active gibberellin content in rice seedlings under light irradiation.

PubMed

Hirose, Fumiaki; Inagaki, Noritoshi; Hanada, Atsushi; Yamaguchi, Shinjiro; Kamiya, Yuji; Miyao, Akio; Hirochika, Hirohiko; Takano, Makoto

2012-09-01

In contrast to a wealth of knowledge about the photoregulation of gibberellin metabolism in dicots, that in monocots remains largely unclear. In this study, we found that a blue light signal triggers reduction of active gibberellin content in rice seedlings with simultaneous repression of two gibberellin 20-oxidase genes (OsGA20ox2 and OsGA20ox4) and acute induction of four gibberellin 2-oxidase genes (OsGA2ox4-OsGA2ox7). For further examination of the regulation of these genes, we established a series of cryptochrome-deficient lines through reverse genetic screening from a Tos17 mutant population and construction of knockdown lines based on an RNA interference technique. By using these lines and phytochrome mutants, we elucidated that cryptochrome 1 (cry1), consisting of two species in rice plants (cry1a and cry1b), is indispensable for robust induction of the GA2ox genes. On the other hand, repression of the GA20ox genes is mediated by phytochromes. In addition, we found that the phytochromes also mediate the repression of a gibberellin 3-oxidase gene (OsGA3ox2) in the light. These results imply that, in rice seedlings, phytochromes mediate the repression of gibberellin biosynthesis capacity, while cry1 mediates the induction of gibberellin inactivation capacity. The cry1 action was demonstrated to be dominant in the reduction of active gibberellin content, but, in rice seedlings, the cumulative effects of these independent actions reduced active gibberellin content in the light. This pathway design in which different types of photoreceptors independently but cooperatively regulate active gibberellin content is unique from the viewpoint of dicot research. This redundancy should provide robustness to the response in rice plants.

Exposure assessment of heavy metals on abandoned metal mine areas by ingestion of soil, crop plant and groundwater

NASA Astrophysics Data System (ADS)

Lee, J.-S.; Chon, H.-T.

2003-05-01

In order to assess the risk of adverse health effects on human exposure to arsenic and heavy metals influence by past mining activities, environmental geochemical survey was undertaken in the abandoned metal mine areas (Dongil Au-Ag-Cu-Zn mine, Okdong Cu-Pb-Zn mine, Myungbong Au-Ag mine). Arsenic and other heavy metals were highly elevated in the tailings from the Dongil mine (8,720 As mg/kg, 5.9 Cd mg/kg, 3,610 Cu mg/kg, 5,850 Pb mg/kg, 630 Zn mg/kg). Heavy metals except As from the Okdong mine (53.6 Cd mg/kg, 910 Cu mg/kg, 1,590 Pb mg/kg, 5,720 Zn mg/kg) and As from the Myungbong mine (5,810 As mg/kg) were also elevated. Elevated levels of As, Cd and Zn were also found in agricultural soils from these mine areas. The H.I. (hazard index) values of As and Cd from the Dongil, the Okdong and Myungbong mine areas are higher than 1.0. Therefore, toxic risk for As and Cd exist via exposure (ingestion) of contaminated soil, groundwater and rice grain in these mine areas.

The effect of cooking and washing rice on the bio-accessibility of As, Cu, Fe, V and Zn using an on-line continuous leaching method.

PubMed

Horner, Nolan S; Beauchemin, Diane

2013-01-03

A previously developed method based on continuous on-line leaching with artificial gastro-intestinal fluids was used to determine the bio-accessible fraction of As, Cu, Fe, V and Zn in brown and white rice from California by inductively coupled mass spectrometry (ICP-MS). Saliva generally accounted for the largest percentage of total element leached in comparison to gastric and intestinal juices. Arsenic speciation analysis was performed on the saliva and gastric juice leachates using ion exchange chromatography coupled to ICP-MS. The four most toxic species of As (As(III), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) and As(V)), as well as Cl(-) in the gastric juice leachate, were successfully separated within 5.5min using a simple nitric acid gradient. While cooking rice had relatively little effect on total bio-accessibility, a change in species from As(V) and DMA to As(III) was observed for both types of rice. On the other hand, washing the rice with doubly deionized water prior to cooking removed a large percentage of the total bio-accessible fraction of As, Cu, Fe, V and Zn. Copyright © 2012 Elsevier B.V. All rights reserved.

Hydrothermal synthesis of zinc oxide nanoparticles using rice as soft biotemplate.

PubMed

Ramimoghadam, Donya; Bin Hussein, Mohd Zobir; Taufiq-Yap, Yun Hin

2013-01-01

Rice as a renewable, abundant bio-resource with unique characteristics can be used as a bio-template to synthesize various functional nanomaterials. Therefore, the effect of uncooked rice flour as bio-template on physico-chemical properties, especially the morphology of zinc oxide nanostructures was investigated in this study. The ZnO particles were synthesized through hydrothermal-biotemplate method using zinc acetate-sodium hydroxide and uncooked rice flour at various ratios as precursors at 120°C for 18 hours. The results indicate that rice as a bio-template can be used to modify the shape and size of zinc oxide particles. Different morphologies, namely flake-, flower-, rose-, star- and rod-like structures were obtained with particle size at micro- and nanometer range. Pore size and texture of the resulting zinc oxide particles were found to be template-dependent and the resulting specific surface area enhanced compared to the zinc oxide synthesized without rice under the same conditions. However, optical property particularly the band gap energy is generally quite similar. Pure zinc oxide crystals were successfully synthesized using rice flour as biotemplate at various ratios of zinc salt to rice. The size- and shape-controlled capability of rice to assemble the ZnO particles can be employed for further useful practical applications.

OsGSR1 is involved in crosstalk between gibberellins and brassinosteroids in rice.

PubMed

Wang, Li; Wang, Zhen; Xu, Yunyuan; Joo, Se-Hwan; Kim, Seong-Ki; Xue, Zhen; Xu, Zhihong; Wang, Zhiyong; Chong, Kang

2009-02-01

Gibberellins (GAs) and brassinosteroids (BRs), two growth-promoting phytohormones, regulate many common physiological processes. Their interactions at the molecular level remain unclear. Here, we demonstrate that OsGSR1, a member of the GAST (GA-stimulated transcript) gene family, is induced by GA and repressed by BR. RNA interference (RNAi) transgenic rice plants with reduced OsGSR1 expression show phenotypes similar to plants deficient in BR, including short primary roots, erect leaves and reduced fertility. The OsGSR1 RNAi transgenic rice shows a reduced level of endogenous BR, and the dwarf phenotype could be rescued by the application of brassinolide. The yeast two-hybrid assay revealed that OsGSR1 interacts with DIM/DWF1, an enzyme that catalyzes the conversion from 24-methylenecholesterol to campesterol in BR biosynthesis. These results suggest that OsGSR1 activates BR synthesis by directly regulating a BR biosynthetic enzyme at the post-translational level. Furthermore, OsGSR1 RNAi plants show a reduced sensitivity to GA treatment, an increased expression of the GA biosynthetic gene OsGA20ox2, which is feedback inhibited by GA signaling, and an elevated level of endogenous GA: together, these suggest that OsGSR1 is a positive regulator of GA signaling. These results demonstrate that OsGSR1 plays important roles in both BR and GA pathways, and also mediates an interaction between the two signaling pathways.

[Long-term effects of tillage methods on heavy metal accumulation and availability in purple paddy soil].

PubMed

Chang, Tong-Ju; Cui, Xiao-Qiang; Ruan, Zhen; Zhao, Xiu-Lan

2014-06-01

A long-term experiment, conducted at Southwest University since 1990, was used to evaluate the effect of tillage methods on the total and available contents of heavy metals (Fe, Mn, Cu, Zn, Pb, Cd) in the profile of purple paddy soil and the contents of those metals in root, stem leaf and brown rice. The experiment included five tillage methods: conventional tillage, paddy-upland rotation, no-tillage and fallow in winter, ridge-no-tillage and compartments-no-tillage. The results showed that the total concentrations of Fe, Cu, Zn, Pb and Cd in the soil profile had no significant differences among five treatments, but it was found that total Mn has a significant decline in 0-20 cm under conventional tillage, paddy-upland rotation and no-tillage and fallow in winter compared with ridge-no-tillage and compartments-no-tillage. The availability of Fe, Cu, Zn, Pb and Cd decreased with the increase of soil depth in all treatments, but the availability of Mn was found to be the highest in the 20-40 cm layers except those in the paddy-upland rotation. In the ploughed layer, the contents of available Fe, Mn was the highest in paddy-upland rotation, while the contents of available Zn and Pb was the highest in conventional tillage, but tillage treatments had not significant influence to the contents of available Cu. Correlation analysis showed that available Fe was significantly negatively related to the pH values and significantly negatively related to the organic matter of soils, available Mn was significantly negatively related to the pH values and organic matter of soils, whereas the available Zn was significantly positively related to total Zn. The contents of Fe, Mn in rice root, the contents of Fe, Mn, Cu and Cd in rice straw and Cu in brown rice were higher under paddy-upland rotation, ridge-no-tillage and compartments-no-tillage than those in conventional tillage and no-tillage and fellow in winter. Paddy-upland rotation can significantly lower the migration coefficient value of Cd in brown rice, and the Pb, Cd concentration in brown rice in the treatment of paddy-upland rotation was lower than the upper limit (< 0.2 mg x kg(-1)) of the National Standard for Food Hygiene for Cd concentration. The content of Fe in root was significantly and negatively related with soil pH and significantly and positively related with soil available Fe, the content of Mn in root was significantly negatively related with soil pH and significantly positively related with soil available Mn, the content of Mn in straw was significantly negatively related with soil pH, significantly positively related with soil total Mn and significantly positively related with soil available Mn, the content of Cu in straw and brown rice was significantly negatively related with soil pH, the content of Zn was significant related with soil pH and significant related with soil CEC. The content of Fe in root, Mn in root and straw and Cd in straw was positively related with soil available Fe, Mn and Cd, respectively, but was negatively related with pH in plough layer soil, Zn in straw was also negatively related with plough layer soil pH. From the results as above, it is concluded that different tillage methods can change the values of soil pH, alter the availability of heavy metal in soils, consequently affect uptake of heavy metal by rice. Of the tillage methods, paddy-upland rotation could increase the availability of Fe and Mn, but decrease the availability of Zn, Pb and Cd in purple paddy soils. Paddy-upland rotation can also increase the contents of Fe, Mn in rice root and straw, but decrease Cd content in brown rice, and could reduce the Pb, Cd contents in brown rice in a certain extent, however, attention should be given to long-term paddy-upland rotation cause of leaching of soil surface Mn.

Impact of Multi-Micronutrient Fortified Rice on Hemoglobin, Iron and Vitamin A Status of Cambodian Schoolchildren: a Double-Blind Cluster-Randomized Controlled Trial.

PubMed

Perignon, Marlène; Fiorentino, Marion; Kuong, Khov; Dijkhuizen, Marjoleine A; Burja, Kurt; Parker, Megan; Chamnan, Chhoun; Berger, Jacques; Wieringa, Frank T

2016-01-07

In Cambodia, micronutrient deficiencies remain a critical public health problem. Our objective was to evaluate the impact of multi-micronutrient fortified rice (MMFR) formulations, distributed through a World Food Program school-meals program (WFP-SMP), on the hemoglobin concentrations and iron and vitamin A (VA) status of Cambodian schoolchildren. The FORISCA-UltraRice+NutriRice study was a double-blind, cluster-randomized, placebo-controlled trial. Sixteen schools participating in WFP-SMP were randomly assigned to receive extrusion-fortified rice (UltraRice Original, UltraRice New (URN), or NutriRice) or unfortified rice (placebo) six days a week for six months. Four additional schools not participating in WFP-SMP were randomly selected as controls. A total of 2440 schoolchildren (6-16 years old) participated in the biochemical study. Hemoglobin, iron status, estimated using inflammation-adjusted ferritin and transferrin receptors concentrations, and VA status, assessed using inflammation-adjusted retinol-binding protein concentration, were measured at the baseline, as well as at three and six months. Baseline prevalence of anemia, depleted iron stores, tissue iron deficiency, marginal VA status and VA deficiency were 15.6%, 1.4%, 51.0%, 7.9%, and 0.7%, respectively. The strongest risk factors for anemia were hemoglobinopathy, VA deficiency, and depleted iron stores (all p < 0.01). After six months, children receiving NutriRice and URN had 4 and 5 times less risk of low VA status, respectively, in comparison to the placebo group. Hemoglobin significantly increased (+0.8 g/L) after three months for the URN group in comparison to the placebo group; however, this difference was no longer significant after six months, except for children without inflammation. MMFR containing VA effectively improved the VA status of schoolchildren. The impact on hemoglobin and iron status was limited, partly by sub-clinical inflammation. MMFR combined with non-nutritional approaches addressing anemia and inflammation should be further investigated.

The minor spliceosomal protein U11/U12-31K is an RNA chaperone crucial for U12 intron splicing and the development of dicot and monocot plants.

PubMed

Kwak, Kyung Jin; Jung, Hyun Ju; Lee, Kwang Ho; Kim, Young Soon; Kim, Won Yong; Ahn, Sung Ju; Kang, Hunseung

2012-01-01

U12 intron-specific spliceosomes contain U11 and U12 small nuclear ribonucleoproteins and mediate the removal of U12 introns from precursor-mRNAs. Among the several proteins unique to the U12-type spliceosomes, an Arabidopsis thaliana AtU11/U12-31K protein has been shown to be indispensible for proper U12 intron splicing and for normal growth and development of Arabidopsis plants. Here, we assessed the functional roles of the rice (Oryza sativa) OsU11/U12-31K protein in U12 intron splicing and development of plants. The U11/U12-31K transcripts were abundantly expressed in the shoot apical meristems (SAMs) of Arabidopsis and rice. Ectopic expression of OsU11/U12-31K in AtU11/U12-31K-defecient Arabidopsis mutant complemented the incorrect U12 intron splicing and abnormal development phenotypes of the Arabidopsis mutant plants. Impaired cell division activity in the SAMs and inflorescence stems observed in the AtU11/U12-31K-deficient mutant was completely recovered to normal by the expression of OsU11/U12-31K. Similar to Arabidopsis AtU11/U12-31K, rice OsU11/U12-31K was determined to harbor RNA chaperone activity. Collectively, the present findings provide evidence for the emerging idea that the U11/U12-31K protein is an indispensible RNA chaperone that functions in U12 intron splicing and is necessary for normal development of monocotyledonous plants as well as dicotyledonous plants.

Chemical methods and phytoremediation of soil contaminated with heavy metals.

PubMed

Chen, H M; Zheng, C R; Tu, C; Shen, Z G

2000-07-01

The effects of chemical amendments (calcium carbonate (CC), steel sludge (SS) and furnace slag (FS)) on the growth and uptake of cadmium (Cd) by wetland rice, Chinese cabbage and wheat grown in a red soil contaminated with Cd were investigated using a pot experiment. The phytoremediation of heavy metal contaminated soil with vetiver grass was also studied in a field plot experiment. Results showed that treatments with CC, SS and FS decreased Cd uptake by wetland rice, Chinese cabbage and wheat by 23-95% compared with the unamended control. Among the three amendments, FS was the most efficient at suppressing Cd uptake by the plants, probably due to its higher content of available silicon (Si). The concentrations of zinc (Zn), lead (Pb) and Cd in the shoots of vetiver grass were 42-67%, 500-1200% and 120-260% higher in contaminated plots than in control, respectively. Cadmium accumulation by vetiver shoots was 218 g Cd/ha at a soil Cd concentration of 0.33 mg Cd/kg. It is suggested that heavy metal-contaminated soil could be remediated with a combination of chemical treatments and plants.

Plasticity of DNA methylation and gene expression under zinc deficiency in Arabidopsis roots.

PubMed

Chen, Xiaochao; Schönberger, Brigitte; Menz, Jochen; Ludewig, Uwe

2018-05-25

DNA methylation is a heritable chromatin modification that maintains chromosome stability, regulates transposon silencing and appears to be involved in gene expression in response to environmental conditions. Environmental stress alters DNA methylation patterns that are correlated with gene expression differences. Here, genome-wide differential DNA-methylation was identified upon prolonged Zn deficiency, leading to hypo- and hyper-methylated chromosomal regions. Preferential CpG methylation changes occurred in gene promoters and gene bodies, but did not overlap with transcriptional start sites. Methylation changes were also prominent in transposable elements. By contrast, non-CG methylation differences were exclusively found in promoters of protein coding genes and in transposable elements. Strongly Zn deficiency-induced genes and their promoters were mostly non-methylated, irrespective of Zn supply. Differential DNA methylation in the CpG and CHG, but not in the CHH context, was found close to a few up-regulated Zn-deficiency genes. However, the transcriptional Zn-deficiency response in roots appeared little correlated with associated DNA methylation changes in promoters or gene bodies. Furthermore, under Zn deficiency, developmental defects were identified in an Arabidopsis mutant lacking non-CpG methylation. The root methylome thus responds specifically to a micro-nutrient deficiency and is important for efficient Zn utilization at low availability, but the relationship of differential methylation and differentially expressed genes is surprisingly poor.

Role of the node in controlling traffic of cadmium, zinc, and manganese in rice

PubMed Central

Yamaguchi, Noriko; Ishikawa, Satoru; Abe, Tadashi; Baba, Koji; Terada, Yasuko

2012-01-01

Heavy metals are transported to rice grains via the phloem. In rice nodes, the diffuse vascular bundles (DVBs), which enclose the enlarged elliptical vascular bundles (EVBs), are connected to the panicle and have a morphological feature that facilitates xylem-to-phloem transfer. To find a mechanism for restricting cadmium (Cd) transport into grains, the distribution of Cd, zinc (Zn), manganese (Mn), and sulphur (S) around the vascular bundles in node I (the node beneath the panicle) of Oryza sativa ‘Koshihikari’ were compared 1 week after heading. Elemental maps of Cd, Zn, Mn, and S in the vascular bundles of node I were obtained by synchrotron micro-X-ray fluorescence spectrometry and electron probe microanalysis. In addition, Cd K-edge microfocused X-ray absorption near-edge structure analyses were used to identify the elements co-ordinated with Cd. Both Cd and S were mainly distributed in the xylem of the EVB and in the parenchyma cell bridge (PCB) surrounding the EVB. Zn accumulated in the PCB, and Mn accumulated around the protoxylem of the EVB. Cd was co-ordinated mainly with S in the xylem of the EVB, but with both S and O in the phloem of the EVB and in the PCB. The EVB in the node retarded horizontal transport of Cd toward the DVB. By contrast, Zn was first stored in the PCB and then efficiently transferred toward the DVB. Our results provide evidence that transport of Cd, Zn, and Mn is differentially controlled in rice nodes, where vascular bundles are functionally interconnected. PMID:22291135

Mapping of available heavy metals in Catamarca (Argentina)

NASA Astrophysics Data System (ADS)

Roca, N.; Pazos, M. S.; Bech, J.

2009-04-01

Copper, iron, manganese and zinc are four essential elements for plant growth. Mapping heavy metal migration and distribution in soils is a preliminary step in assessing heavy metal availability in soils. However, data of qualitative and quantitative trace elements composition of soils of Argentina are scarce. Despite the small amounts required by plants, agricultural soils are usually deficient in one or more micronutrients, therefore, their concentration in plant tissues falls below the levels that allow optimal growth. Soil nature plays a fundamental role in the availability of micronutrients and their behaviour at a soil-plant level. The aim of this study is to determine the plant availability and areas of deficiency in agricultural soils with risk of salinization. The presented maps have been elaborated on the basis of the information provided by the monochromatic aerial photographs, scale 1:7000 and projected using the topographic information of the National Topographic Maps. Soils were sampled according to the spatial variation of soil types and land use. Sampling points were geo-referenced. Soil samples were analyzed at the laboratory for complete physicochemical and mineralogical characteristics. The percentage of organic matter is the determining factor in the presence and distribution of the available metals in the soils of the studied area, being the top horizon the one of greatest accumulation. CuDTPA, FeDPTA and MnDPTA are mobile within the profile, whereas ZnDPTA remains adsorbed without vertical displacement. ZnDTPA is the only available metal which also shows differences due to soil salinity and textural classes. However, soil geochemical conditions imply low extractability and a certain difficulty for micronutrient absorption by plants.

Comparison of soil and foliar zinc application for enhancing grain zinc content of wheat when grown on potentially zinc-deficient calcareous soils.

PubMed

Zhao, Ai-qing; Tian, Xiao-hong; Cao, Yu-xian; Lu, Xin-chun; Liu, Ting

2014-08-01

The concentration of Zn and phytic acid in wheat grain has important implications for human health. We conducted field and greenhouse experiments to compare the efficacy of soil and foliar Zn fertilisation in improving grain Zn concentration and bioavailability in wheat (Triticum aestivum L.) grain grown on potentially Zn-deficient calcareous soil. Results from the 2-year field experiment indicated that soil Zn application increased soil DTPA-Zn by an average of 174%, but had no significant effect on grain Zn concentration. In contrast, foliar Zn application increased grain Zn concentration by an average of 61%, and Zn bioavailability by an average of 36%. Soil DTPA-Zn concentrations varied depending on wheat cultivars. There were also significant differences in grain phytic acid concentration among the cultivars. A laboratory experiment indicated that Zn (from ZnSO4 ) had a low diffusion coefficient in this calcareous soil. Compared to soil Zn application, foliar Zn application is more effective in improving grain Zn content of wheat grown in potentially Zn-deficient calcareous soils. © 2013 Society of Chemical Industry.

Overexpression of rice serotonin N-acetyltransferase 1 in transgenic rice plants confers resistance to cadmium and senescence and increases grain yield.

PubMed

Lee, Kyungjin; Back, Kyoungwhan

2017-04-01

While ectopic overexpression of serotonin N-acetyltransferase (SNAT) in plants has been accomplished using animal SNAT genes, ectopic overexpression of plant SNAT genes in plants has not been investigated. Because the plant SNAT protein differs from that of animals in its subcellular localization and enzyme kinetics, its ectopic overexpression in plants would be expected to give outcomes distinct from those observed from overexpression of animal SNAT genes in transgenic plants. Consistent with our expectations, we found that transgenic rice plants overexpressing rice (Oryza sativa) SNAT1 (OsSNAT1) did not show enhanced seedling growth like that observed in ovine SNAT-overexpressing transgenic rice plants, although both types of plants exhibited increased melatonin levels. OsSNAT1-overexpressing rice plants did show significant resistance to cadmium and senescence stresses relative to wild-type controls. In contrast to tomato, melatonin synthesis in rice seedlings was not induced by selenium and OsSNAT1 transgenic rice plants did not show tolerance to selenium. T 2 homozygous OsSNAT1 transgenic rice plants exhibited increased grain yield due to increased panicle number per plant under paddy field conditions. These benefits conferred by ectopic overexpression of OsSNAT1 had not been observed in transgenic rice plants overexpressing ovine SNAT, suggesting that plant SNAT functions differently from animal SNAT in plants. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

DOSE-DEPENDENT TRANSITIONS IN MECHANISMS OF TOXICITY: ZINC CASE EXAMPLE

EPA Science Inventory

Zinc (Zn) is an essential trace element. Maternal Zn deficiency can result in complications of pregnancy and inadequate supply of Zn to the conceptus can interfere with the development of numerous organ systems. Maternal dietary Zn deficiency has been shown to be teratogenic in a...

Dietary calcium and zinc deficiency risks are decreasing but remain prevalent

PubMed Central

Kumssa, Diriba B.; Joy, Edward J. M.; Ander, E. Louise; Watts, Michael J.; Young, Scott D.; Walker, Sue; Broadley, Martin R.

2015-01-01

Globally, more than 800 million people are undernourished while >2 billion people have one or more chronic micronutrient deficiencies (MNDs). More than 6% of global mortality and morbidity burdens are associated with undernourishment and MNDs. Here we show that, in 2011, 3.5 and 1.1 billion people were at risk of calcium (Ca) and zinc (Zn) deficiency respectively due to inadequate dietary supply. The global mean dietary supply of Ca and Zn in 2011 was 684 ± 211 and 16 ± 3 mg capita−1 d−1 (±SD) respectively. Between 1992 and 2011, global risk of deficiency of Ca and Zn decreased from 76 to 51%, and 22 to 16%, respectively. Approximately 90% of those at risk of Ca and Zn deficiency in 2011 were in Africa and Asia. To our knowledge, these are the first global estimates of dietary Ca deficiency risks based on food supply. We conclude that continuing to reduce Ca and Zn deficiency risks through dietary diversification and food and agricultural interventions including fortification, crop breeding and use of micronutrient fertilisers will remain a significant challenge. PMID:26098577

Dietary calcium and zinc deficiency risks are decreasing but remain prevalent

NASA Astrophysics Data System (ADS)

Kumssa, Diriba B.; Joy, Edward J. M.; Ander, E. Louise; Watts, Michael J.; Young, Scott D.; Walker, Sue; Broadley, Martin R.

2015-06-01

Globally, more than 800 million people are undernourished while >2 billion people have one or more chronic micronutrient deficiencies (MNDs). More than 6% of global mortality and morbidity burdens are associated with undernourishment and MNDs. Here we show that, in 2011, 3.5 and 1.1 billion people were at risk of calcium (Ca) and zinc (Zn) deficiency respectively due to inadequate dietary supply. The global mean dietary supply of Ca and Zn in 2011 was 684 ± 211 and 16 ± 3 mg capita-1 d-1 (±SD) respectively. Between 1992 and 2011, global risk of deficiency of Ca and Zn decreased from 76 to 51%, and 22 to 16%, respectively. Approximately 90% of those at risk of Ca and Zn deficiency in 2011 were in Africa and Asia. To our knowledge, these are the first global estimates of dietary Ca deficiency risks based on food supply. We conclude that continuing to reduce Ca and Zn deficiency risks through dietary diversification and food and agricultural interventions including fortification, crop breeding and use of micronutrient fertilisers will remain a significant challenge.

Influence of zinc deficiency on cell-membrane fluidity in Jurkat, 3T3 and IMR-32 cells.

PubMed Central

Verstraeten, Sandra V; Zago, M Paola; MacKenzie, Gerardo G; Keen, Carl L; Oteiza, Patricia I

2004-01-01

We investigated whether zinc deficiency can affect plasma membrane rheology. Three cell lines, human leukaemia T-cells (Jurkat), rat fibroblasts (3T3) and human neuroblastoma cells (IMR-32), were cultured for 48 h in control medium, in zinc-deficient medium (1.5 microM zinc; 1.5 Zn), or in the zinc-deficient medium supplemented with 15 microM zinc (15 Zn). The number of viable cells was lower in the 1.5 Zn group than in the control and 15 Zn groups. The frequency of apoptosis was higher in the 1.5 Zn group than in the control and 15 Zn groups. Membrane fluidity was evaluated using the 6-(9-anthroyloxy)stearic acid and 16-(9-anthroyloxy)palmitic acid probes. Membrane fluidity was higher in 1.5 Zn cells than in the control cells; no differences were observed between control cells and 15 Zn cells. The effect of zinc deficiency on membrane fluidity at the water/lipid interface was associated with a higher phosphatidylserine externalization. The higher membrane fluidity in the hydrophobic region of the bilayer was correlated with a lower content of arachidonic acid. We suggest that the increased fluidity of the membrane secondary to zinc deficiency is in part due to a decrease in arachidonic acid content and the apoptosis-related changes in phosphatidylserine distribution. PMID:14629198

Silicon-zinc interactions and potential roles for dietary zinc and copper in minimizing silica urolithiasis in rats.

PubMed

Stewart, S R; Emerick, R J; Kayongo-Male, H

1993-04-01

Two 8-wk experiments were conducted with Sprague-Dawley weanling rats to determine whether interactions occurring between Zn and Si, or a nutritional deficiency of either Cu or Zn, affect silica urolith formation. In Exp. 1, concentrations of 0, 540, and 2,700 mg of Si/kg of diet from tetraethylorthosilicate were used with dietary Zn concentrations of 4, 12, and 500 mg/kg of diet in a 3 x 3 factorial arrangement. In Exp. 2, copper at 1 or 5 mg/kg of diet and Zn at 4, 12, and 500 mg/kg of diet were used in a 2 x 3 factorial arrangement. All diets in Exp. 2 contained 2,700 mg of Si/kg. Silica uroliths occurred in all treatments providing, 2,700 mg of Si/kg of diet. There was a trend (P = .17) toward a reduction of silica urolith incidence with increasing concentrations of dietary Zn in Exp. 1. In Exp. 2, a deficiency of Zn, and a Cu deficiency exacerbated by 500 mg of Zn/kg of diet, increased (P < .05) silica urolith formation. An antagonism between Si and Zn, as demonstrated previously in the rat, may not be of a sufficient magnitude to be applicable to the prevention of silica urolithiasis. The data further demonstrate that Zn deficiency and, to a lesser extent, Cu deficiency contributed to silica urolith formation in rats fed diets having a high content of absorbable Si. However, 540 mg of Si/kg of diet may potentiate the metabolic activity of Zn, as indicated by a 23% Si-mediated weight gain response in Zn-deficient rats.

Bioaccumulation of heavy metals and two organochlorine pesticides (DDT and BHC) in crops irrigated with secondary treated waste water.

PubMed

Mishra, Virendra K; Upadhyay, Alka R; Tripathi, B D

2009-09-01

Four crop plants Oryza sativa (rice), Solanum melongena (brinjal), Spinacea oleracea (spinach) and Raphanus sativus (radish) were grown to study the impact of secondary treated municipal waste water irrigation. These plants were grown in three plots each of 0.5 ha, and irrigated with secondary treated waste water from a sewage treatment plant. Sludge from the same sewage treatment plant was applied as manure. Cultivated plants were analyzed for accumulation of heavy metals and pesticides. Results revealed the accumulation of six heavy metals cadmium (Cd), chromium (Cr), iron (Fe), copper (Cu), nickel (Ni), and zinc (Zn) as well as two pesticides [1,1-bis(p-chlorophenyl)-2,2,2-trichloroethane; DDT] and benzene hexa chloride (BHC). Order of the plants for the extent of bioaccumulation was S. oleracea > R. sativus > S. melongena > O. sativa. The study has shown the secondary treated waste water can be a source of contamination to the soil and plants.

Comparisons of protein, lipid, phenolics, γ-oryzanol, vitamin E, and mineral contents in bran layer of sodium azide-induced red rice mutants.

PubMed

Jeng, Toong Long; Ho, Pei Tzu; Shih, Yi Ju; Lai, Chia Chi; Wu, Min Tze; Sung, Jih Min

2011-06-01

The bran part of red rice grain is concentrated with many phytochemicals, including proanthocyanidins, oryzanol and vitamin E, that exert beneficial effects on human health, but it contains low levels of essential minerals such as Fe and Zn. In the present study, the protein, lipid, phytochemicals and mineral contents in bran samples were compared among red rice SA-586 and its NaN₃-induced mutants. The plant heights of NaN₃-induced mutants were decreased. The contents of protein, lipid, total phenolics, total flavonoids, total anthocyanins, total proanthocyanidins, total γ-oryzanol, total tocopherols and total tocotrienols also varied among the tested mutants. The brans of mutants M-18, M-56 and M-50 contained more proanthocyanidins, γ-oryzanol, vitamin E than that of SA-586, respectively. M-54 accumulated more Fe content (588.7 mg kg⁻¹ bran dry weight) than SA-586 (100.1 mg kg⁻¹ bran dry weight). The brans of M-18, M-50 and M-56 are good sources of proanthocyanidins, vitamin E and γ-oryzanol, respectively, while the bran of M-54 is rich in Fe. Thus these mutants could be used to produce high-value phytochemicals or Fe byproducts from bran during rice grain milling or as genetic resources for rice improvement programs. Copyright © 2011 Society of Chemical Industry.

Rice ABI5-Like1 Regulates Abscisic Acid and Auxin Responses by Affecting the Expression of ABRE-Containing Genes1[W][OA

PubMed Central

Yang, Xi; Yang, Ya-Nan; Xue, Liang-Jiao; Zou, Mei-Juan; Liu, Jian-Ying; Chen, Fan; Xue, Hong-Wei

2011-01-01

Abscisic acid (ABA) regulates plant development and is crucial for plant responses to biotic and abiotic stresses. Studies have identified the key components of ABA signaling in Arabidopsis (Arabidopsis thaliana), some of which regulate ABA responses by the transcriptional regulation of downstream genes. Here, we report the functional identification of rice (Oryza sativa) ABI5-Like1 (ABL1), which is a basic region/leucine zipper motif transcription factor. ABL1 is expressed in various tissues and is induced by the hormones ABA and indole-3-acetic acid and stress conditions including salinity, drought, and osmotic pressure. The ABL1 deficiency mutant, abl1, shows suppressed ABA responses, and ABL1 expression in the Arabidopsis abi5 mutant rescued the ABA sensitivity. The ABL1 protein is localized to the nucleus and can directly bind ABA-responsive elements (ABREs; G-box) in vitro. A gene expression analysis by DNA chip hybridization confirms that a large proportion of down-regulated genes of abl1 are involved in stress responses, consistent with the transcriptional activating effects of ABL1. Further studies indicate that ABL1 regulates the plant stress responses by regulating a series of ABRE-containing WRKY family genes. In addition, the abl1 mutant is hypersensitive to exogenous indole-3-acetic acid, and some ABRE-containing genes related to auxin metabolism or signaling are altered under ABL1 deficiency, suggesting that ABL1 modulates ABA and auxin responses by directly regulating the ABRE-containing genes. PMID:21546455

Effects of Zinc Supplementation on DNA Damage in Rats with Experimental Kidney Deficiency.

PubMed

Yegin, Sevim Çiftçi; Dede, Semiha; Mis, Leyla; Yur, Fatmagül

2017-04-01

This study was carried out to determine the effect of zinc on oxidative DNA damage in rats with experimental acute and chronic kidney deficiency. Six groups of five Wistar-Albino rats each were assigned as controls (C), acute kidney deficiency (AKD), zinc-supplemented (+Zn), acute kidney deficiency, zinc-supplemented (AKD + Zn), chronic kidney deficiency (CKD) and zinc-supplemented chronic kidney deficiency (CKD + Zn). The levels of 8-Oxo-2'-deoxyguanosine (8-OHdG) were determined, being the lowest in the CKD group (p < 0.05), higher in the C group than those of rats with CKD but lower than that of all the other groups (p < 0.05). There were no significant differences between the controls and the CKD + Zn group, or between the AKD and the +Zn groups. Among all groups, the highest 8-OHdG level was found in the AKD + Zn group (p < 0.05). DNA damage was greater in acute renal failure than in rats with chronic renal failure. The DNA damage in the zinc group was significantly higher than in the controls.

Rice (Oryza sativa L) plantation affects the stability of biochar in paddy soil.

PubMed

Wu, Mengxiong; Feng, Qibo; Sun, Xue; Wang, Hailong; Gielen, Gerty; Wu, Weixiang

2015-05-05

Conversion of rice straw into biochar for soil amendment appears to be a promising method to increase long-term carbon sequestration and reduce greenhouse gas (GHG) emissions. The stability of biochar in paddy soil, which is the major determining factor of carbon sequestration effect, depends mainly on soil properties and plant functions. However, the influence of plants on biochar stability in paddy soil remains unclear. In this study, bulk and surface characteristics of the biochars incubated without rice plants were compared with those incubated with rice plants using a suite of analytical techniques. Results showed that although rice plants had no significant influence on the bulk characteristics and decomposition rates of the biochar, the surface oxidation of biochar particles was enhanced by rice plants. Using (13)C labeling we observed that rice plants could significantly increase carbon incorporation from biochar into soil microbial biomass. About 0.047% of the carbon in biochar was incorporated into the rice plants during the whole rice growing cycle. These results inferred that root exudates and transportation of biochar particles into rice plants might decrease the stability of biochar in paddy soil. Impact of plants should be considered when predicting carbon sequestration potential of biochar in soil systems.

Rice (Oryza sativa L) plantation affects the stability of biochar in paddy soil

PubMed Central

Wu, Mengxiong; Feng, Qibo; Sun, Xue; Wang, Hailong; Gielen, Gerty; Wu, Weixiang

2015-01-01

Conversion of rice straw into biochar for soil amendment appears to be a promising method to increase long-term carbon sequestration and reduce greenhouse gas (GHG) emissions. The stability of biochar in paddy soil, which is the major determining factor of carbon sequestration effect, depends mainly on soil properties and plant functions. However, the influence of plants on biochar stability in paddy soil remains unclear. In this study, bulk and surface characteristics of the biochars incubated without rice plants were compared with those incubated with rice plants using a suite of analytical techniques. Results showed that although rice plants had no significant influence on the bulk characteristics and decomposition rates of the biochar, the surface oxidation of biochar particles was enhanced by rice plants. Using 13C labeling we observed that rice plants could significantly increase carbon incorporation from biochar into soil microbial biomass. About 0.047% of the carbon in biochar was incorporated into the rice plants during the whole rice growing cycle. These results inferred that root exudates and transportation of biochar particles into rice plants might decrease the stability of biochar in paddy soil. Impact of plants should be considered when predicting carbon sequestration potential of biochar in soil systems. PMID:25944542

Mutation in Mg-Protoporphyrin IX Monomethyl Ester Cyclase Decreases Photosynthesis Capacity in Rice

PubMed Central

Wang, Xuexia; Huang, Rongfeng; Quan, Ruidang

2017-01-01

In photosynthesis, the pigments chlorophyll a/b absorb light energy to convert to chemical energy in chloroplasts. Though most enzymes of chlorophyll biosynthesis from glutamyl-tRNA to chlorophyll a/b have been identified, the exact composition and regulation of the multimeric enzyme Mg-protoporphyrin IX monomethyl ester cyclase (MPEC) is largely unknown. In this study, we isolated a rice pale-green leaf mutant m167 with yellow-green leaf phenotype across the whole lifespan. Chlorophyll content decreases 43–51% and the granal stacks of chloroplasts becomes thinner in m167. Chlorophyll fluorescence parameters, including Fv/Fm (the maximum quantum efficiency of PSII) and quantum yield of PSII (Y(II)), were lower in m167 than those in wild type plants (WT), and photosynthesis rate decreases 40% in leaves of m167 mutant compared with WT plants, which lead to yield reduction in m167. Genetic analysis revealed that yellow-green leaf phenotype of m167 is controlled by a single recessive genetic locus. By positional cloning, a single mutated locus, G286A (Alanine 96 to Threonine in protein), was found in the coding sequence of LOC_Os01g17170 (Rice Copper Response Defect 1, OsCRD1), encoding a putative subunit of MPEC. Expression profile analysis demonstrated that OsCRD1 is mainly expressed in green tissues of rice. Sequence alignment analysis of CRD1 indicated that Alanine 96 is very conserved in all green plants and photosynthetic bacteria. OsCRD1 protein mainly locates in chloroplast and the point mutation A96T in OsCRD1 does not change its location. Therefore, Alanine96 of OsCRD1 might be fundamental for MPEC activity, mutation of which leads to deficiency in chlorophyll biosynthesis and chloroplast development and decreases photosynthetic capacity in rice. PMID:28129387

Zn2+ reduction induces neuronal death with changes in voltage-gated potassium and sodium channel currents.

PubMed

Tian, Kun; He, Cong-Cong; Xu, Hui-Nan; Wang, Yu-Xiang; Wang, Hong-Gang; An, Di; Heng, Bin; Pang, Wei; Jiang, Yu-Gang; Liu, Yan-Qiang

2017-05-01

In the present study, cultured rat primary neurons were exposed to a medium containing N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN), a specific cell membrane-permeant Zn 2+ chelator, to establish a model of free Zn 2+ deficiency in neurons. The effects of TPEN-mediated free Zn 2+ ion reduction on neuronal viability and on the performance of voltage-gated sodium channels (VGSCs) and potassium channels (Kvs) were assessed. Free Zn 2+ deficiency 1) markedly reduced the neuronal survival rate, 2) reduced the peak amplitude of I Na , 3) shifted the I Na activation curve towards depolarization, 4) modulated the sensitivity of sodium channel voltage-dependent inactivation to a depolarization voltage, and 5) increased the time course of recovery from sodium channel inactivation. In addition, free Zn 2+ deficiency by TPEN notably enhanced the peak amplitude of transient outward K + currents (I A ) and delayed rectifier K + currents (I K ), as well as caused hyperpolarization and depolarization directional shifts in their steady-state activation curves, respectively. Zn 2+ supplementation reversed the effects induced by TPEN. Our results indicate that free Zn 2+ deficiency causes neuronal damage and alters the dynamic characteristics of VGSC and Kv currents. Thus, neuronal injury caused by free Zn 2+ deficiency may correlate with its modulation of the electrophysiological properties of VGSCs and Kvs. Copyright © 2017 Elsevier GmbH. All rights reserved.

Ribosomal protein S6 kinase1 coordinates with TOR-Raptor2 to regulate thylakoid membrane biosynthesis in rice.

PubMed

Sun, Linxiao; Yu, Yonghua; Hu, Weiqin; Min, Qiming; Kang, Huiling; Li, Yilu; Hong, Yue; Wang, Xuemin; Hong, Yueyun

2016-07-01

Ribosomal protein S6 kinase (S6K) functions as a key component in the target of rapamycin (TOR) pathway involved in multiple processes in eukaryotes. The role and regulation of TOR-S6K in lipid metabolism remained unknown in plants. Here we provide genetic and pharmacological evidence that TOR-Raptor2-S6K1 is important for thylakoid galactolipid biosynthesis and thylakoid grana modeling in rice (Oryza sativa L.). Genetic suppression of S6K1 caused pale yellow-green leaves, defective thylakoid grana architecture. S6K1 directly interacts with Raptor2, a core component in TOR signaling, and S6K1 activity is regulated by Raptor2 and TOR. Plants with suppressed Raptor2 expression or reduced TOR activity by inhibitors mimicked the S6K1-deficient phenotype. A significant reduction in galactolipid content was found in the s6k1, raptor2 mutant or TOR-inhibited plants, which was accompanied by decreased transcript levels of the set of genes such as lipid phosphate phosphatase α5 (LPPα5), MGDG synthase 1 (MGD1), and DGDG synthase 1 (DGD1) involved in galactolipid synthesis, compared to the control plants. Moreover, loss of LPPα5 exhibited a similar phenotype with pale yellow-green leaves. These results suggest that TOR-Raptor2-S6K1 is important for modulating thylakoid membrane lipid biosynthesis, homeostasis, thus enhancing thylakoid grana architecture and normal photosynthesis ability in rice. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of zinc deficiency and supplementation on leptin and leptin receptor expression in pregnant mice.

PubMed

Ueda, Hidenori; Nakai, Taketo; Konishi, Tatsuya; Tanaka, Keiichi; Sakazaki, Fumitoshi; Min, Kyong-Son

2014-01-01

Leptin is an adipose-derived hormone that primarily regulates energy balance in response to nutrition. Human placental cells produce leptin, whereas murine placental cells produce soluble leptin receptors (Ob-R). However, the roles of these proteins during pregnancy have not been elucidated completely. As an essential metal, zinc (Zn) is central to insulin biosynthesis and energy metabolism. In the present study, the effects of Zn deficiency and supplementation on maternal plasma leptin and soluble Ob-R regulation in pregnant mice placentas were examined using enzyme-linked immunosorbent assay, reverse transcription-polymerase chain reaction, and Western blotting. Nutritional Zn deficiency significantly reduced plasma insulin concentrations and fetal and placental weights in pregnant mice. Plasma leptin concentrations in pregnant mice also increased 20- to 40-fold compared with those in non-pregnant mice. Although dietary Zn deficiency and supplementation did not affect plasma leptin concentrations in non-pregnant mice, Zn-deficient pregnant mice had significantly reduced plasma leptin concentrations and adipose leptin mRNA expression. In contrast, Zn-supplemented pregnant mice had increased plasma leptin concentrations without increased adipose leptin mRNA expression. Placental soluble Ob-R mRNA expression also decreased in Zn-deficient mice and tended to increase in Zn-supplemented mice. These results indicate that Zn influences plasma leptin concentrations by modulating mRNA expression of soluble Ob-R in the placenta, and leptin in visceral fat during pregnancy. These data suggest that both adipose and placenta-derived leptin system are involved in the regulation of energy metabolism during fetal growth.

Zinc biofortification improves phytochemicals and amino-acidic profile in Brassica oleracea cv. Bronco.

PubMed

Barrameda-Medina, Yurena; Blasco, Begoña; Lentini, Marco; Esposito, Sergio; Baenas, Nieves; Moreno, Diego A; Ruiz, Juan M

2017-05-01

Zn deficiency is currently listed as a major risk factor for human health. Recently, a complimentary solution to mineral malnutrition termed 'biofortification' has been proposed. The aim of this study was to investigate the possible effects of a Zn-biofortification program on Zn levels, amino acidic profile and the phytochemicals content in an edible leafy vegetable, such as Brassica oleracea cv. Bronco. Our results indicate that supplementation of 80-100μM Zn is optimal for maintaining the normal growth of plants and to promote the major Zn concentration in the edible part of B. oleracea. Any further increase of Zn supply induced an accumulation of total amino acids, and increased the enzymatic activities involved in sulfur assimilation and synthesis of phenols, finally resulting in a foliar accumulation of glucosinolates and phenolic compounds. Thus, it could be proposed that the growth of B. oleracea under 80-100μM Zn may increase the intake of this micronutrient and other beneficial compunds for the human health. Copyright © 2017 Elsevier B.V. All rights reserved.

Antimicrobial Activity of Plant Extracts from Aloe Vera, Citrus Hystrix, Sabah Snake Grass and Zingiber Officinale against Pyricularia Oryzae that causes Rice Blast Disease in Paddy Plants

NASA Astrophysics Data System (ADS)

Uda, M. N. A.; Harzana Shaari, N.; Shamiera. Said, N.; Hulwani Ibrahim, Nur; Akhir, Maisara A. M.; Khairul Rabani Hashim, Mohd; Salimi, M. N.; Nuradibah, M. A.; Hashim, Uda; Gopinath, Subash C. B.

2018-03-01

Rice blast disease, caused by the fungus known as Pyricularia oryzae, has become an important and serious disease of rice worldwide. Around 50% of production may be lost in a field moderately affected by infection and each year the fungus destroys rice, which is enough to feed an estimated 60 million people. Therefore, use of herbal plants offer an alternative for the management of plant diseases. Herbal plant like Aloe vera, Citrus hystrix, Sabah snake grass and Zingiber officinale extracts can be used for controlling disease of rice blast. In this study, these four herbal plants were used for evaluating antimicrobial activity against rice plant fungus Pyricularia oryzae, which causes rice blast disease.

Increasing rice plant growth by Trichoderma sp.

NASA Astrophysics Data System (ADS)

Doni, Febri; Isahak, Anizan; Zain, Che Radziah Che Mohd; Sulaiman, Norela; Fathurahman, F.; Zain, Wan Nur Syazana Wan Mohd.; Kadhimi, Ahsan A.; Alhasnawi, Arshad Naji; Anhar, Azwir; Yusoff, Wan Mohtar Wan

2016-11-01

Trichoderma sp. is a plant growth promoting fungi in many crops. Initial observation on the ability to enhance rice germination and vigor have been reported. In this study, the effectiveness of a local isolate Trichoderma asprellum SL2 to enhance rice seedling growth was assessed experimentally under greenhouse condition using a completely randomized design. Results showed that inoculation of rice plants with Trichoderma asprellum SL2 significantly increase rice plants height, root length, wet weight, leaf number and biomass compared to untreated rice plants (control). The result of this study can serve as a reference for further work on the application of beneficial microorganisms to enhance rice production.

Mapping of a Cellulose-Deficient Mutant Named dwarf1-1 in Sorghum bicolor to the Green Revolution Gene gibberellin20-oxidase Reveals a Positive Regulatory Association between Gibberellin and Cellulose Biosynthesis.

PubMed

Petti, Carloalberto; Hirano, Ko; Stork, Jozsef; DeBolt, Seth

2015-09-01

Here, we show a mechanism for expansion regulation through mutations in the green revolution gene gibberellin20 (GA20)-oxidase and show that GAs control biosynthesis of the plants main structural polymer cellulose. Within a 12,000 mutagenized Sorghum bicolor plant population, we identified a single cellulose-deficient and male gametophyte-dysfunctional mutant named dwarf1-1 (dwf1-1). Through the Sorghum propinquum male/dwf1-1 female F2 population, we mapped dwf1-1 to a frameshift in GA20-oxidase. Assessment of GAs in dwf1-1 revealed ablation of GA. GA ablation was antagonistic to the expression of three specific cellulose synthase genes resulting in cellulose deficiency and growth dwarfism, which were complemented by exogenous bioactive gibberellic acid application. Using quantitative polymerase chain reaction, we found that GA was positively regulating the expression of a subset of specific cellulose synthase genes. To cross reference data from our mapped Sorghum sp. allele with another monocotyledonous plant, a series of rice (Oryza sativa) mutants involved in GA biosynthesis and signaling were isolated, and these too displayed cellulose deficit. Taken together, data support a model whereby suppressed expansion in green revolution GA genes involves regulation of cellulose biosynthesis. © 2015 American Society of Plant Biologists. All Rights Reserved.

Cell wall targeted in planta iron accumulation enhances biomass conversion and seed iron concentration in Arabidopsis and rice

DOE PAGES

Yang, Haibing; Wei, Hui; Ma, Guojie; ...

2016-04-07

Conversion of nongrain biomass into liquid fuel is a sustainable approach to energy demands as global population increases. Previously, we showed that iron can act as a catalyst to enhance the degradation of lignocellulosic biomass for biofuel production. However, direct addition of iron catalysts to biomass pretreatment is diffusion-limited, would increase the cost and complexity of biorefinery unit operations and may have deleterious environmental impacts. Here, we show a new strategy for in planta accumulation of iron throughout the volume of the cell wall where iron acts as a catalyst in the deconstruction of lignocellulosic biomass. We engineered CBM-IBP fusionmore » polypeptides composed of a carbohydrate-binding module family 11 (CBM11) and an iron-binding peptide (IBP) for secretion into Arabidopsis and rice cell walls. CBM-IBP transformed Arabidopsis and rice plants show significant increases in iron accumulation and biomass conversion compared to respective controls. Further, CBM-IBP rice shows a 35% increase in seed iron concentration and a 40% increase in seed yield in greenhouse experiments. In conclusion, CBM-IBP rice potentially could be used to address iron deficiency, the most common and widespread nutritional disorder according to the World Health Organization.« less

Cell wall targeted in planta iron accumulation enhances biomass conversion and seed iron concentration in Arabidopsis and rice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Haibing; Wei, Hui; Ma, Guojie

Conversion of nongrain biomass into liquid fuel is a sustainable approach to energy demands as global population increases. Previously, we showed that iron can act as a catalyst to enhance the degradation of lignocellulosic biomass for biofuel production. However, direct addition of iron catalysts to biomass pretreatment is diffusion-limited, would increase the cost and complexity of biorefinery unit operations and may have deleterious environmental impacts. Here, we show a new strategy for in planta accumulation of iron throughout the volume of the cell wall where iron acts as a catalyst in the deconstruction of lignocellulosic biomass. We engineered CBM-IBP fusionmore » polypeptides composed of a carbohydrate-binding module family 11 (CBM11) and an iron-binding peptide (IBP) for secretion into Arabidopsis and rice cell walls. CBM-IBP transformed Arabidopsis and rice plants show significant increases in iron accumulation and biomass conversion compared to respective controls. Further, CBM-IBP rice shows a 35% increase in seed iron concentration and a 40% increase in seed yield in greenhouse experiments. CBM-IBP rice potentially could be used to address iron deficiency, the most common and widespread nutritional disorder according to the World Health Organization.« less

Cell wall targeted in planta iron accumulation enhances biomass conversion and seed iron concentration in Arabidopsis and rice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Haibing; Wei, Hui; Ma, Guojie

Conversion of nongrain biomass into liquid fuel is a sustainable approach to energy demands as global population increases. Previously, we showed that iron can act as a catalyst to enhance the degradation of lignocellulosic biomass for biofuel production. However, direct addition of iron catalysts to biomass pretreatment is diffusion-limited, would increase the cost and complexity of biorefinery unit operations and may have deleterious environmental impacts. Here, we show a new strategy for in planta accumulation of iron throughout the volume of the cell wall where iron acts as a catalyst in the deconstruction of lignocellulosic biomass. We engineered CBM-IBP fusionmore » polypeptides composed of a carbohydrate-binding module family 11 (CBM11) and an iron-binding peptide (IBP) for secretion into Arabidopsis and rice cell walls. CBM-IBP transformed Arabidopsis and rice plants show significant increases in iron accumulation and biomass conversion compared to respective controls. Further, CBM-IBP rice shows a 35% increase in seed iron concentration and a 40% increase in seed yield in greenhouse experiments. In conclusion, CBM-IBP rice potentially could be used to address iron deficiency, the most common and widespread nutritional disorder according to the World Health Organization.« less

NOD promoter-controlled AtIRT1 expression functions synergistically with NAS and FERRITIN genes to increase iron in rice grains.

PubMed

Boonyaves, Kulaporn; Gruissem, Wilhelm; Bhullar, Navreet K

2016-02-01

Rice is a staple food for over half of the world's population, but it contains only low amounts of bioavailable micronutrients for human nutrition. Consequently, micronutrient deficiency is a widespread health problem among people who depend primarily on rice as their staple food. Iron deficiency anemia is one of the most serious forms of malnutrition. Biofortification of rice grains for increased iron content is an effective strategy to reduce iron deficiency. Unlike other grass species, rice takes up iron as Fe(II) via the IRON REGULATED TRANSPORTER (IRT) in addition to Fe(III)-phytosiderophore chelates. We expressed Arabidopsis IRT1 (AtIRT1) under control of the Medicago sativa EARLY NODULIN 12B promoter in our previously developed high-iron NFP rice lines expressing NICOTIANAMINE SYNTHASE (AtNAS1) and FERRITIN. Transgenic rice lines expressing AtIRT1 alone had significant increases in iron and combined with NAS and FERRITIN increased iron to 9.6 µg/g DW in the polished grains that is 2.2-fold higher as compared to NFP lines. The grains of AtIRT1 lines also accumulated more copper and zinc but not manganese. Our results demonstrate that the concerted expression of AtIRT1, AtNAS1 and PvFERRITIN synergistically increases iron in both polished and unpolished rice grains. AtIRT1 is therefore a valuable transporter for iron biofortification programs when used in combination with other genes encoding iron transporters and/or storage proteins.

Heavy metals in Australian grown and imported rice and vegetables on sale in Australia: health hazard.

PubMed

Rahman, M Azizur; Rahman, Mohammad Mahmudur; Reichman, Suzie M; Lim, Richard P; Naidu, Ravi

2014-02-01

Dietary exposure to heavy metals is a matter of concern for human health risk through the consumption of rice, vegetables and other major foodstuffs. In the present study, we investigated concentrations of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn) in Australian grown and imported rice and vegetables on sale in Australia. The mean concentrations of Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn in Australian grown rice were 7.5 µg kg(-1), 21 µg kg(-1), 144 µg kg(-1), 2.9 mg kg(-1), 24.4 mg kg(-1), 166 µg kg(-1), 375 µg kg(-1), and 17.1 mg kg(-1) dry weight (d. wt.), respectively. Except Cd, heavy metal concentrations in Australian grown rice were higher than Bangladeshi rice on sale in Australia. However, the concentrations of Cd, Cr, Cu, and Ni in Indian rice on sale in Australia were higher than Australian grown rice. The concentrations of Cu and Ni in Vietnamese rice, and that of Cd, Cr, Cu, Ni, and Pb in Thai rice on sale in Australia were also higher than Australian grown rice. Heavy metal concentrations in Pakistani rice on sale in Australia were substantially lower than that in Australian grown rice. In Australian grown rice varieties, the concentrations of heavy metals were considerably higher in brown rice varieties than white rice varieties, indicating Australian brown rice as a potential source of dietary heavy metals for Australian consumers. The mean concentrations of heavy metals in Australian grown and Bangladeshi vegetables on sale in Australia were also determined. Some of the Australian grown and Bangladeshi vegetables contained heavy metals higher than Australian standard maximum limits indicating them as potential sources of dietary heavy metals for Australian consumers. Further investigation is required to estimate health risks of heavy metals from rice and vegetables consumption for Australian consumers. © 2013 Published by Elsevier Inc.

Herbicidal and antioxidant responses of transgenic rice overexpressing Myxococcus xanthus protoporphyrinogen oxidase.

PubMed

Jung, Sunyo; Back, Kyoungwhan

2005-05-01

We analyzed the herbicidal and antioxidant defense responses of transgenic rice plants that overexpressed the Myxococcus xanthus protoporphyrinogen oxidase gene. Leaf squares of the wild-type incubated with oxyfluorfen were characterized by necrotic leaf lesions and increases in conductivity and malonyldialdehyde levels, whereas transgenic lines M4 and M7 did not show any change with up to 100 microM oxyfluorfen. The wild-type had decreased F(v)/F(m) and produced a high level of H(2)O(2) at 18 h after foliar application of oxyfluorfen, whereas transgenic lines M4 and M7 were unaffected. In response to oxyfluorfen, violaxanthin, beta-carotene, and chlorophylls (Chls) decreased in wild-type plants, whereas antheraxanthin and zeaxanthin increased. Only a slight decline in Chls was observed in transgenic lines at 48 h after oxyfluorfen treatment. Noticeable increases of cytosolic Cu/Zn-superoxide dismutase, peroxidase isozymes 1 and 2, and catalase were observed after at 48 h of oxyfluorfen treatment in the wild-type. Non-enzymatic antioxidants appeared to respond faster to oxyfluorfen-induced photodynamic stress than did enzymatic antioxidants. Protective responses for the detoxification of active oxygen species were induced to counteract photodynamic stress in oxyfluorfen-treated, wild-type plants. However, oxyfluorfen-treated, transgenic plants suffered less oxidative stress, confirming increased herbicidal resistance resulted from dual expression of M. xanthus Protox in chloroplasts and mitochondria.

Genome-wide analysis of autophagy-associated genes in foxtail millet (Setaria italica L.) and characterization of the function of SiATG8a in conferring tolerance to nitrogen starvation in rice.

PubMed

Li, Weiwei; Chen, Ming; Wang, Erhui; Hu, Liqin; Hawkesford, Malcolm J; Zhong, Li; Chen, Zhu; Xu, Zhaoshi; Li, Liancheng; Zhou, Yongbin; Guo, Changhong; Ma, Youzhi

2016-10-12

Autophagy is a cellular degradation process that is highly evolutionarily-conserved in yeast, plants, and animals. In plants, autophagy plays important roles in regulating intracellular degradation and recycling of amino acids in response to nutrient starvation, senescence, and other environmental stresses. Foxtail millet (Setaria italica) has strong resistance to stresses and has been proposed as an ideal material for use in the study of the physiological mechanisms of abiotic stress tolerance in plants. Although the genome sequence of foxtail millet (Setaria italica) is available, the characteristics and functions of abiotic stress-related genes remain largely unknown for this species. A total of 37 putative ATG (autophagy-associated genes) genes in the foxtail millet genome were identified. Gene duplication analysis revealed that both segmental and tandem duplication events have played significant roles in the expansion of the ATG gene family in foxtail millet. Comparative synteny mapping between the genomes of foxtail millet and rice suggested that the ATG genes in both species have common ancestors, as their ATG genes were primarily located in similar syntenic regions. Gene expression analysis revealed the induced expression of 31 SiATG genes by one or more phytohormone treatments, 26 SiATG genes by drought, salt and cold, 24 SiATG genes by darkness and 25 SiATG genes by nitrogen starvation. Results of qRT-PCR showing that among 37 SiATG genes, the expression level of SiATG8a was the highest after nitrogen starvation treatment 24 h, suggesting its potential role in tolerance to nutrient starvation. Moreover, the heterologous expression of SiATG8a in rice improved nitrogen starvation tolerance. Compared to wild type rice, the transgenic rice performed better and had higher aboveground total nitrogen content when the plants were grown under nitrogen starvation conditions. Our results deepen understanding about the characteristics and functions of ATG genes in foxtail millet and also identify promising new genetic resources that should be of use in future efforts to develop varieties of foxtail millet and other crop species that have resistance to nitrogen deficiency stress.

Use of banker plant system for sustainable management of the most important insect pest in rice fields in China

PubMed Central

Zheng, Xusong; Lu, Yanhui; Zhu, Pingyang; Zhang, Facheng; Tian, Junce; Xu, Hongxing; Chen, Guihua; Nansen, Christian; Lu, Zhongxian

2017-01-01

To meet the World’s food demand, there is a growing need for sustainable pest management practices. This study describes the results from complementary laboratory and field studies of a “banker plant system” for sustainable management of the rice brown planthopper (BPH) (Nilaparvata lugens Stål) – the economically most important rice pest in Asian rice growing areas. The banker plant system consisted of planting a grass species, Leersia sayanuka, adjacent to rice fields. L. sayanuka is the host plant of a planthopper, Nilaparvata muiri. An egg parasitoid, Anagrus nilaparvatae, parasitizes eggs of both BPH and N. muiri, and its establishment and persistence are improved through plantings of L. sayanuka and thereby attraction of N. muiri. Laboratory results showed that BPH was unable to complete its life cycle on L. sayanuka, and N. muiri could not complete its life cycle on rice. Thus, planting L. sayanuka did not increase the risk of planthopper damage to rice fields. Field studies showed that BPH densities were significantly lower in rice fields with banker plant system compared to control rice fields without banker plant system. PMID:28367978

Use of banker plant system for sustainable management of the most important insect pest in rice fields in China.

PubMed

Zheng, Xusong; Lu, Yanhui; Zhu, Pingyang; Zhang, Facheng; Tian, Junce; Xu, Hongxing; Chen, Guihua; Nansen, Christian; Lu, Zhongxian

2017-04-03

To meet the World's food demand, there is a growing need for sustainable pest management practices. This study describes the results from complementary laboratory and field studies of a "banker plant system" for sustainable management of the rice brown planthopper (BPH) (Nilaparvata lugens Stål) - the economically most important rice pest in Asian rice growing areas. The banker plant system consisted of planting a grass species, Leersia sayanuka, adjacent to rice fields. L. sayanuka is the host plant of a planthopper, Nilaparvata muiri. An egg parasitoid, Anagrus nilaparvatae, parasitizes eggs of both BPH and N. muiri, and its establishment and persistence are improved through plantings of L. sayanuka and thereby attraction of N. muiri. Laboratory results showed that BPH was unable to complete its life cycle on L. sayanuka, and N. muiri could not complete its life cycle on rice. Thus, planting L. sayanuka did not increase the risk of planthopper damage to rice fields. Field studies showed that BPH densities were significantly lower in rice fields with banker plant system compared to control rice fields without banker plant system.

Paddy-field contamination with 134Cs and 137Cs due to Fukushima Dai-ichi Nuclear Power Plant accident and soil-to-rice transfer coefficients.

PubMed

Endo, Satoru; Kajimoto, Tsuyoshi; Shizuma, Kiyoshi

2013-02-01

The transfer coefficient (TF) from soil to rice plants of (134)Cs and (137)Cs in the form of radioactive deposition from the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident in March 2011 was investigated in three rice paddy fields in Minami-Soma City. Rice crops were planted in the following May and harvested at the end of September. Soil cores of 30-cm depth were sampled from rice-planted paddy fields to measure (134)Cs and (137)Cs radioactivity at 5-cm intervals. (134)Cs and (137)Cs radioactivity was also measured in rice ears (rice with chaff), straws and roots. The rice ears were subdivided into chaff, brown rice, polished rice and rice bran, and the (134)Cs and (137)Cs radioactivity concentration of each plant part was measured to calculate the respective TF from the soil. The TF of roots was highest at 0.48 ± 0.10 in the field where the (40)K concentration in the soil core was relatively low, in comparison with TF values of 0.31 and 0.38 in other fields. Similar trends could be found for the TF of whole rice plants, excluding roots. The TF of rice ears was relatively low at 0.019-0.026. The TF of chaff, rice bran, brown rice and polished rice was estimated to be 0.049, 0.10-0.16, 0.013-0.017 and 0.005-0.013, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoadley, J.E.; Leinart, A.S.; Cousins, R.J.

Intestinal 65Zn transport and metallothionein levels were examined in rats fed zinc-adequate and zinc-deficient diets and in rats subjected to an overnight fast. 65Zn uptake by intestines perfused with 1.5 microM 65Zn was greater in both zinc-deficient and fasted groups than in the control group. Mucosal retention of 65Zn was also greater in the zinc-deficient group but not in the fasted group. The greater 65Zn uptake in the fasted group was associated with a compartment that readily released 65Zn back into the lumen. Kinetic analysis of the rate of 65Zn transfer to the vascular space (absorption) showed that 65Zn absorptionmore » involved approximately 3% of mucosal 65Zn in a 40-min perfusion period. The half-life (t1/2) of this mucosal 65Zn rapid transport pool corresponded directly to changes in intestinal metallothionein levels. Both metallothionein and t1/2 were higher in the fasted group and lower in the zinc-deficient group than in controls. While the rate of 65Zn transport from this rapid transport pool decreased with increasing metallothionein level, the predicted pool size increased when the metallothionein level was elevated by fasting. These results indicate that the rate of zinc absorption is inversely related to intestinal metallothionein levels, but the portion of mucosal 65Zn available for absorption is directly related to intestinal metallothionein.« less

Over-expression of the Arabidopsis proton-pyrophosphatase AVP1 enhances transplant survival, root mass, and fruit development under limiting phosphorus conditions

PubMed Central

Yang, Haibing; Zhang, Xiao; Gaxiola, Roberto A.; Xu, Guohua; Peer, Wendy Ann; Murphy, Angus S.

2014-01-01

Phosphorus (P), an element required for plant growth, fruit set, fruit development, and fruit ripening, can be deficient or unavailable in agricultural soils. Previously, it was shown that over-expression of a proton-pyrophosphatase gene AVP1/AVP1D (AVP1DOX) in Arabidopsis, rice, and tomato resulted in the enhancement of root branching and overall mass with the result of increased mineral P acquisition. However, although AVP1 over-expression also increased shoot biomass in Arabidopsis, this effect was not observed in tomato under phosphate-sufficient conditions. AVP1DOX tomato plants exhibited increased rootward auxin transport and root acidification compared with control plants. AVP1DOX tomato plants were analysed in detail under limiting P conditions in greenhouse and field trials. AVP1DOX plants produced 25% (P=0.001) more marketable ripened fruit per plant under P-deficient conditions compared with the controls. Further, under low phosphate conditions, AVP1DOX plants displayed increased phosphate transport from leaf (source) to fruit (sink) compared to controls. AVP1DOX plants also showed an 11% increase in transplant survival (P<0.01) in both greenhouse and field trials compared with the control plants. These results suggest that selection of tomato cultivars for increased proton pyrophosphatase gene expression could be useful when selecting for cultivars to be grown on marginal soils. PMID:24723407

The identification of 'hotspots' of heavy metal pollution in soil-rice systems at a regional scale in eastern China.

PubMed

Li, Wanlu; Xu, Binbin; Song, Qiujin; Liu, Xingmei; Xu, Jianming; Brookes, Philip C

2014-02-15

Chinese agricultural soils and crops are suffering from increasing damage from heavy metals, which are introduced from various pollution sources including agriculture, traffic, mining and especially the flourishing private metal recycling industry. In this study, 219 pairs of rice grain and corresponding soil samples were collected from Wenling in Zhejiang Province to identify the spatial relationship and pollution hotspots of Cd, Cu, Ni and Zn in the soil-rice system. The mean soil concentrations of heavy metals were 0.316 mg kg(-1) for Cd, 47.3 mg kg(-1) for Cu, 31.7 mg kg(-1) for Ni and 131 mg kg(-1) for Zn, and the metal concentrations in rice grain were 0.132 mg kg(-1) for Cd, 2.46 mg kg(-1) for Cu, 0.223 mg kg(-1) for Ni and 17.4 mg kg(-1) for Zn. The coefficient of variability (CV) of soil Cd, Cu and rice Cd were 147%, 146% and 180%, respectively, indicating an extensive variability. While the CVs of other metals ranged from 23.4% to 84.3% with a moderate variability. Kriging interpolation procedure and the Local Moran's I index detected the locations of pollution hotspots of these four metals. Cd and Cu had a very similar spatial pattern, with contamination hotspots located simultaneously in the northwestern part of the study area, and there were obvious hotspots for soil Zn in the north area, while in the northeast for soil Ni. The existence of hotspots may be due to industrialization and other anthropogenic activities. An Enrichment Index (EI) was employed to measure the uptake of heavy metals by rice. The results indicated that the accumulation and availability of heavy metals in the soil-rice system may be influenced by both soil heavy metal concentrations and soil physico-chemical properties. Cross-correlograms quantitatively illustrated that EIs were significantly correlated with soil properties. Soil pH and organic matter were the most important factors controlling the uptake of heavy metals by rice. As results, positive measures should be taken into account to control soil pollution and to curtail metal contamination to the food chain in the areas of Wenling, which were the most polluted by toxic metals. Copyright © 2013 Elsevier B.V. All rights reserved.

Golden rice: Development, Nutritional Assessment, and Potential for Alleviating Vitamin A Deficiency

USDA-ARS?s Scientific Manuscript database

Golden Rice (GR) is a transgenic product engineered to produce beta-carotene in the rice endosperm. It has been developed as a means to combat vitamin A malnutrition, which exists throughout much of the developing world (especially in rice eating populations) and can lead to blindness, increased sus...

A rhamnose-deficient lipopolysaccharide mutant of Rhizobium sp. IRBG74 is defective in root colonization and beneficial interactions with its flooding-tolerant hosts Sesbania cannabina and wetland rice.

PubMed

Mitra, Shubhajit; Mukherjee, Arijit; Wiley-Kalil, Audrey; Das, Seema; Owen, Heather; Reddy, Pallavolu M; Ané, Jean-Michel; James, Euan K; Gyaneshwar, Prasad

2016-10-01

Rhizobium sp. IRBG74 develops a classical nitrogen-fixing symbiosis with the aquatic legume Sesbania cannabina (Retz.). It also promotes the growth of wetland rice (Oryza sativa L.), but little is known about the rhizobial determinants important for these interactions. In this study, we analyzed the colonization of S. cannabina and rice using a strain of Rhizobium sp. IRBG74 dually marked with β-glucuronidase and the green fluorescent protein. This bacterium colonized S. cannabina by crack entry and through root hair infection under flooded and non-flooded conditions, respectively. Rhizobium sp. IRBG74 colonized the surfaces of wetland rice roots, but also entered them at the base of lateral roots. It became endophytically established within intercellular spaces in the rice cortex, and intracellularly within epidermal and hypodermal cells. A mutant of Rhizobium sp. IRBG74 altered in the synthesis of the rhamnose-containing O-antigen exhibited significant defects, not only in nodulation and symbiotic nitrogen fixation with S. cannabina, but also in rice colonization and plant growth promotion. Supplementation with purified lipopolysaccharides from the wild-type strain, but not from the mutant, restored the beneficial colonization of rice roots, but not fully effective nodulation of S. cannabina Commonalities and differences in the rhizobial colonization of the roots of wetland legume and rice hosts are discussed. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Enhancing tolerance of rice (Oryza sativa) to simulated acid rain by exogenous abscisic acid.

PubMed

Wu, Xi; Liang, Chanjuan

2017-02-01

Abscisic acid (ABA) regulates much important plant physiological and biochemical processes and induces tolerance to different stresses. Here, we studied the regulation of exogenous ABA on adaptation of rice seedlings to simulated acid rain (SAR) stress by measuring biomass dry weight, stomatal conductance, net photosynthesis rate, nutrient elements, and endogenous hormones. The application of 10 μM ABA alleviated the SAR-induced inhibition on growth, stomatal conductance, net photosynthesis rate, and decreases in contents of nutrient (K, Mg, N, and P) and hormone (auxin, gibberellins, and zeatin). Moreover, 10 μM ABA could stimulate the Ca content as signaling molecules under SAR stress. Contrarily, the application of 100 μM ABA aggravated the SAR-induced inhibition on growth, stomatal conductance, net photosynthesis rate, and contents of nutrient and hormone. The results got after a 5-day recovery (without SAR) show that exogenous 10 μM ABA can promote self-restoration process in rice whereas 100 μM ABA hindered the restoration by increasing deficiency of nutrients and disturbing the balance of hormones. These results confirmed that exogenous ABA at proper concentration could enhance the tolerance of rice to SAR stress.

Relationship of /sup 65/Zn absorption kinetics to intestinal metallothionein in rats: effects of zinc depletion and fasting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoadley, J.E.; Leinart, A.S.; Cousins, R.J.

1988-04-01

Intestinal 65Zn transport and metallothionein levels were examined in rats fed zinc-adequate and zinc-deficient diets and in rats subjected to an overnight fast. 65Zn uptake by intestines perfused with 1.5 microM 65Zn was greater in both zinc-deficient and fasted groups than in the control group. Mucosal retention of 65Zn was also greater in the zinc-deficient group but not in the fasted group. The greater 65Zn uptake in the fasted group was associated with a compartment that readily released 65Zn back into the lumen. Kinetic analysis of the rate of 65Zn transfer to the vascular space (absorption) showed that 65Zn absorptionmore » involved approximately 3% of mucosal 65Zn in a 40-min perfusion period. The half-life (t1/2) of this mucosal 65Zn rapid transport pool corresponded directly to changes in intestinal metallothionein levels. Both metallothionein and t1/2 were higher in the fasted group and lower in the zinc-deficient group than in controls. While the rate of 65Zn transport from this rapid transport pool decreased with increasing metallothionein level, the predicted pool size increased when the metallothionein level was elevated by fasting. These results indicate that the rate of zinc absorption is inversely related to intestinal metallothionein levels, but the portion of mucosal 65Zn available for absorption is directly related to intestinal metallothionein.« less

Silicon alleviates drought stress of rice plants by improving plant water status, photosynthesis and mineral nutrient absorption.

PubMed

Chen, Wei; Yao, Xiaoqin; Cai, Kunzheng; Chen, Jining

2011-07-01

Drought is a major constraint for rice production in the rainfed lowlands in China. Silicon (Si) has been verified to play an important role in enhancing plant resistance to environmental stress. Two near-isogenic lines of rice (Oryza sativa L.), w-14 (drought susceptible) and w-20 (drought resistant), were selected to study the effects of exogenous Si application on the physiological traits and nutritional status of rice under drought stress. In wet conditions, Si supply had no effects on growth and physiological parameters of rice plants. Drought stress was found to reduce dry weight, root traits, water potential, photosynthetic parameters, basal quantum yield (F(v)/F(0)), and maximum quantum efficiency of PSII photochemistry (F(v)/F(m)) in rice plants, while Si application significantly increased photosynthetic rate (Pr), transpiration rate (Tr), F(v)/F(0), and F(v)/F(m) of rice plants under drought stress. In addition, water stress increased K, Na, Ca, Mg, Fe content of rice plants, but Si treatment significantly reduced these nutrient level. These results suggested that silicon application was useful to increase drought resistance of rice through the enhancement of photochemical efficiency and adjustment of the mineral nutrient absorption in rice plants.

Neutropenia restores virulence to an attenuated Cu,Zn superoxide dismutase-deficient Haemophilus ducreyi strain in the swine model of chancroid.

PubMed

San Mateo, L R; Toffer, K L; Orndorff, P E; Kawula, T H

1999-10-01

Haemophilus ducreyi causes chancroid, a sexually transmitted cutaneous genital ulcer disease associated with increased heterosexual transmission of human immunodeficiency virus. H. ducreyi expresses a periplasmic copper-zinc superoxide dismutase (Cu, Zn SOD) that protects the bacterium from killing by exogenous superoxide in vitro. We hypothesized that the Cu,Zn SOD would protect H. ducreyi from immune cell killing, enhance survival, and affect ulcer development in vivo. In order to test this hypothesis and study the role of the Cu,Zn SOD in H. ducreyi pathogenesis, we compared a Cu,Zn SOD-deficient H. ducreyi strain to its isogenic wild-type parent with respect to survival and ulcer development in immunocompetent and immunosuppressed pigs. The Cu,Zn SOD-deficient strain was recovered from significantly fewer inoculated sites and in significantly lower numbers than the wild-type parent strain or a merodiploid (sodC+ sodC) strain after infection of immunocompetent pigs. In contrast, survival of the wild-type and Cu,Zn SOD-deficient strains was not significantly different in pigs that were rendered neutropenic by treatment with cyclophosphamide. Ulcer severity in pigs was not significantly different between sites inoculated with wild type and sites inoculated with Cu,Zn SOD-deficient H. ducreyi. Our data suggest that the periplasmic Cu,Zn SOD is an important virulence determinant in H. ducreyi, protecting the bacterium from host immune cell killing and contributing to survival and persistence in the host.

Neutropenia Restores Virulence to an Attenuated Cu,Zn Superoxide Dismutase-Deficient Haemophilus ducreyi Strain in the Swine Model of Chancroid

PubMed Central

San Mateo, Lani R.; Toffer, Kristen L.; Orndorff, Paul E.; Kawula, Thomas H.

1999-01-01

Haemophilus ducreyi causes chancroid, a sexually transmitted cutaneous genital ulcer disease associated with increased heterosexual transmission of human immunodeficiency virus. H. ducreyi expresses a periplasmic copper-zinc superoxide dismutase (Cu,Zn SOD) that protects the bacterium from killing by exogenous superoxide in vitro. We hypothesized that the Cu,Zn SOD would protect H. ducreyi from immune cell killing, enhance survival, and affect ulcer development in vivo. In order to test this hypothesis and study the role of the Cu,Zn SOD in H. ducreyi pathogenesis, we compared a Cu,Zn SOD-deficient H. ducreyi strain to its isogenic wild-type parent with respect to survival and ulcer development in immunocompetent and immunosuppressed pigs. The Cu,Zn SOD-deficient strain was recovered from significantly fewer inoculated sites and in significantly lower numbers than the wild-type parent strain or a merodiploid (sodC+ sodC) strain after infection of immunocompetent pigs. In contrast, survival of the wild-type and Cu,Zn SOD-deficient strains was not significantly different in pigs that were rendered neutropenic by treatment with cyclophosphamide. Ulcer severity in pigs was not significantly different between sites inoculated with wild type and sites inoculated with Cu,Zn SOD-deficient H. ducreyi. Our data suggest that the periplasmic Cu,Zn SOD is an important virulence determinant in H. ducreyi, protecting the bacterium from host immune cell killing and contributing to survival and persistence in the host. PMID:10496915

Bt rice does not disrupt the host-searching behavior of the parasitoid Cotesia chilonis

PubMed Central

Liu, Qingsong; Romeis, Jörg; Yu, Huilin; Zhang, Yongjun; Li, Yunhe; Peng, Yufa

2015-01-01

We determined whether plant volatiles help explain why Cotesia chilonis (a parasitoid of the target pest Chilo suppressalis) is less abundant in Bt than in non-Bt rice fields. Olfactometer studies revealed that C. chilonis females responded similarly to undamaged Bt and non-Bt rice plants. Parasitoids preferred rice plants damaged by 3rd-instar larvae of C. suppressalis, but did not differentiate between caterpillar-infested Bt and non-Bt plants. According to GC-MS analyses of rice plant volatiles, undamaged Bt and non-Bt rice plants emitted the same number of volatile compounds and there were no significant differences in the quantity of each volatile compound between the treatments. When plants were infested with and damaged by C. suppressalis larvae, both Bt and non-Bt rice plants emitted higher numbers and larger amounts of volatile compounds than undamaged plants, but there were no significant differences between Bt and non-Bt plants. These results demonstrate that the volatile-mediated interactions of rice plants with the parasitoid C. chilonis were not disrupted by the genetic engineering of the plants. We infer that parasitoid numbers are lower in Bt than in non-Bt fields because damage and volatile induction by C. suppressalis larvae are greatly reduced in Bt fields. PMID:26470012

Research in rice fields

USGS Publications Warehouse

,

2000-01-01

Between 1987 and 1999, 2.4-3 million acres of rice were planted annually nationwide. Rice fields are a major component of the contemporary landscapes in the Gulf Coastal Plain, the Mississippi Alluvial Valley, and Central Valley of California. In 1998, approximately 600,000 acres of rice were planted in Louisiana. In the Louisiana plant commodities report for 1998, total value for rice was over $350 million; sugarcane was the only plant commodity that exceeded this value. Louisiana has over 2,000 rice farmers supporting over 12,000 jobs in the state. Rice fields in the United States receive high use by wildlife, especially shorebirds, wading birds, and waterfowl. Waterbirds use rice fields for food, shelter, and breeding habitat.

Virus-Mediated Chemical Changes in Rice Plants Impact the Relationship between Non-Vector Planthopper Nilaparvata lugens Stål and Its Egg Parasitoid Anagrus nilaparvatae Pang et Wang

PubMed Central

Gao, Guanchun; Zhou, Xiaojun; Zheng, Xusong; Sun, Yujian; Yang, Yajun; Tian, Junce; Lu, Zhongxian

2014-01-01

In order to clarify the impacts of southern rice black-streaked dwarf virus (SRBSDV) infection on rice plants, rice planthoppers and natural enemies, differences in nutrients and volatile secondary metabolites between infected and healthy rice plants were examined. Furthermore, the impacts of virus-mediated changes in plants on the population growth of non-vector brown planthopper (BPH), Nilaparvata lugens, and the selectivity and parasitic capability of planthopper egg parasitoid Anagrus nilaparvatae were studied. The results showed that rice plants had no significant changes in amino acid and soluble sugar contents after SRBSDV infection, and SRBSDV-infected plants had no significant effect on population growth of non-vector BPH. A. nilaparvatae preferred BPH eggs both in infected and healthy rice plants, and tended to parasitize eggs on infected plants, but it had no significant preference for infected plants or healthy plants. GC-MS analysis showed that tridecylic aldehyde occurred only in rice plants infected with SRBSDV, whereas octanal, undecane, methyl salicylate and hexadecane occurred only in healthy rice plants. However, in tests of behavioral responses to these five volatile substances using a Y-tube olfactometer, A. nilaparvatae did not show obvious selectivity between single volatile substances at different concentrations and liquid paraffin in the control group. The parasitic capability of A. nilaparvatae did not differ between SRBSDV-infected plants and healthy plant seedlings. The results suggested that SRBSDV-infected plants have no significant impacts on the non-vector planthopper and its egg parasitoid, A. nilaparvatae. PMID:25141278

Virus-mediated chemical changes in rice plants impact the relationship between non-vector planthopper Nilaparvata lugens Stål and its egg parasitoid Anagrus nilaparvatae Pang et Wang.

PubMed

He, Xiaochan; Xu, Hongxing; Gao, Guanchun; Zhou, Xiaojun; Zheng, Xusong; Sun, Yujian; Yang, Yajun; Tian, Junce; Lu, Zhongxian

2014-01-01

In order to clarify the impacts of southern rice black-streaked dwarf virus (SRBSDV) infection on rice plants, rice planthoppers and natural enemies, differences in nutrients and volatile secondary metabolites between infected and healthy rice plants were examined. Furthermore, the impacts of virus-mediated changes in plants on the population growth of non-vector brown planthopper (BPH), Nilaparvata lugens, and the selectivity and parasitic capability of planthopper egg parasitoid Anagrus nilaparvatae were studied. The results showed that rice plants had no significant changes in amino acid and soluble sugar contents after SRBSDV infection, and SRBSDV-infected plants had no significant effect on population growth of non-vector BPH. A. nilaparvatae preferred BPH eggs both in infected and healthy rice plants, and tended to parasitize eggs on infected plants, but it had no significant preference for infected plants or healthy plants. GC-MS analysis showed that tridecylic aldehyde occurred only in rice plants infected with SRBSDV, whereas octanal, undecane, methyl salicylate and hexadecane occurred only in healthy rice plants. However, in tests of behavioral responses to these five volatile substances using a Y-tube olfactometer, A. nilaparvatae did not show obvious selectivity between single volatile substances at different concentrations and liquid paraffin in the control group. The parasitic capability of A. nilaparvatae did not differ between SRBSDV-infected plants and healthy plant seedlings. The results suggested that SRBSDV-infected plants have no significant impacts on the non-vector planthopper and its egg parasitoid, A. nilaparvatae.

The assessment of soil availability and wheat grain status of zinc and iron in Serbia: Implications for human nutrition.

PubMed

Nikolic, Miroslav; Nikolic, Nina; Kostic, Ljiljana; Pavlovic, Jelena; Bosnic, Predrag; Stevic, Nenad; Savic, Jasna; Hristov, Nikola

2016-05-15

The deficiency of zinc (Zn) and iron (Fe) is a global issue causing not only considerable yield losses of food crops but also serious health problems. We have analysed Zn and Fe concentrations in the grains of two bread wheat cultivars along native gradient of micronutrient availability throughout Serbia. Although only 13% of the soil samples were Zn deficient and none was Fe deficient, the levels of these micronutrients in grain were rather low (median values of 21 mg kg(-1) for Zn and 36 mg kg(-1) for Fe), and even less adequate in white flour. Moreover, excessive P fertilization of calcareous soils in the major wheat growing areas strongly correlated with lower grain concentration of Zn. Our results imply that a latent Zn deficiency in wheat grain poses a high risk for grain quality relevant to human health in Serbia, where wheat bread is a staple food. Copyright © 2016 Elsevier B.V. All rights reserved.

Exploiting genotypic variation in plant nutrient accumulation to alleviate micronutrient deficiency in populations.

PubMed

Genc, Yusuf; Humphries, Julia M; Lyons, Graham H; Graham, Robin D

2005-01-01

More than 2 billion people consume diets that are less diverse than 30 years ago, leading to deficiencies in micronutrients, especially iron (Fe), zinc (Zn), selenium (Se), iodine (I), and also vitamin A. A strategy that exploits genetic variability to breed staple crops with enhanced ability to fortify themselves with micronutrients (genetic biofortification) offers a sustainable, cost-effective alternative to conventional supplementation and fortification programs. This is more likely to reach those most in need, has the added advantages of requiring no change in current consumer behaviour to be effective, and is transportable to a range of countries. Research by our group, along with studies elsewhere, has demonstrated conclusively that substantial genotypic variation exists in nutrient (e.g. Fe, Zn) and nutrient promotor (e.g. inulin) concentrations in wheat and other staple foods. A rapid screening technique has been developed for lutein content of wheat and triticale, and also for pro-vitamin A carotenoids in bread wheat. This will allow cost-effective screening of a wider range of genotypes that may reveal greater genotypic variation in these traits. Moreover, deeper understanding of genetic control mechanisms and development of molecular markers will facilitate breeding programs. We suggest that a combined strategy utilising plant breeding for higher micronutrient density; maximising the effects of nutritional promoters (e.g. inulin, vitamin C) by promoting favourable dietary combinations, as well as by plant breeding; and agronomic biofortification (e.g. adding iodide or iodate as fertiliser; applying selenate to cereal crops by spraying or adding to fertiliser) is likely to be the most effective way to improve the nutrition of populations. Furthermore, the importance of detecting and exploiting beneficial interactions is illustrated by our discovery that in Fe-deficient chickens, circulating Fe concentrations can be restored to normal levels by lutein supplementation. Further bioavailability/bioefficacy trials with animals and humans are needed, using varying dietary concentrations of Fe, Zn, carotenoids, inulin, Se and I to elucidate other important interactions in order to optimise delivery in biofortification programs.

Protein Activity of the Fusarium fujikuroi Rhodopsins CarO and OpsA and Their Relation to Fungus–Plant Interaction

PubMed Central

Adam, Alexander; Deimel, Stephan; Pardo-Medina, Javier; García-Martínez, Jorge; Konte, Tilen; Limón, M. Carmen; Avalos, Javier

2018-01-01

Fungi possess diverse photosensory proteins that allow them to perceive different light wavelengths and to adapt to changing light conditions in their environment. The biological and physiological roles of the green light-sensing rhodopsins in fungi are not yet resolved. The rice plant pathogen Fusarium fujikuroi exhibits two different rhodopsins, CarO and OpsA. CarO was previously characterized as a light-driven proton pump. We further analyzed the pumping behavior of CarO by patch-clamp experiments. Our data show that CarO pumping activity is strongly augmented in the presence of the plant hormone indole-3-acetic acid and in sodium acetate, in a dose-dependent manner under slightly acidic conditions. By contrast, under these and other tested conditions, the Neurospora rhodopsin (NR)-like rhodopsin OpsA did not exhibit any pump activity. Basic local alignment search tool (BLAST) searches in the genomes of ascomycetes revealed the occurrence of rhodopsin-encoding genes mainly in phyto-associated or phytopathogenic fungi, suggesting a possible correlation of the presence of rhodopsins with fungal ecology. In accordance, rice plants infected with a CarO-deficient F. fujikuroi strain showed more severe bakanae symptoms than the reference strain, indicating a potential role of the CarO rhodopsin in the regulation of plant infection by this fungus. PMID:29324661

Influence of solution acidity and CaCl2 concentration on the removal of heavy metals from metal-contaminated rice soils.

PubMed

Kuo, S; Lai, M S; Lin, C W

2006-12-01

Soil washing is considered a useful technique for remediating metal-contaminated soils. This study examined the release edges of Cd, Zn, Ni, Cr, Cu or Pb in two contaminated rice soils from central Taiwan. The concentrations exceeding the trigger levels established by the regulatory agency of Taiwan were Cu, Zn, Ni and Cr for the Ho-Mei soil and Pb for the Nan-Tou soil. Successive extractions with HCl ranging from 0 to 0.2 M showed increased release of the heavy metals with declining pH, and the threshold pH value below which a sharp increase in the releases of the heavy metals was highest for Cd, Zn, and Ni (pH 4.6 to 4.9), intermediate for Pb and Cu (3.1 to 3.8) and lowest for Fe (2.1), Al (2.2) and Cr (1.7) for the soils. The low response slope of Ni and Cr particularly for the rice soils make soil washing with the acid up to the highest concentration used ineffective to reduce their concentrations to below trigger levels. Although soil washing with 0.1 M HCl was moderately effective in reducing Cu, Pb, Zn and Cd, which brought pH of the soils to 1.1+/-0.1 (S.D.), the concurrent release of large quantities of Fe and Al make this remediation technique undesirable for the rice soils containing high clay. Successive washings with 0.01 M HCl could be considered an alternative as the dissolution of Fe and Al was minimal, and between 46 to 64% of Cd, Zn, and Cu for the Ho-Mei soil and 45% of Pb in the Na-Tou soil were extracted after four successive extractions with this dilute acid solution. The efficacy of Cd extraction improved if CaCl2 was added to the acid solution. The correlation analysis revealed that Cr extracted was highly correlated (P < 0.001) with Fe extracted, whereas the Cu, Ni, Zn, Cd or Pb extracted was better correlated (P < 0.001) with Al than with Fe extracted. It is possible that the past seasonal soil flooding and drainage in the soils for rice production was conducive to incorporating Cr within the structure of Fe oxide, thereby making them extremely insoluble even in 0.2 M HCl solution. The formation of solid solution of Ni with Al oxide was also possible, making it far less extractable than Cd, Zn, Cu, or Pb with the acid concentrations used.

Overexpression of acetylcholinesterase gene in rice results in enhancement of shoot gravitropism.

PubMed

Yamamoto, Kosuke; Shida, Satoshi; Honda, Yoshihiro; Shono, Mariko; Miyake, Hiroshi; Oguri, Suguru; Sakamoto, Hikaru; Momonoki, Yoshie S

2015-09-25

Acetylcholine (ACh), a known neurotransmitter in animals and acetylcholinesterase (AChE) exists widely in plants, although its role in plant signal transduction is unclear. We previously reported AChE in Zea mays L. might be related to gravitropism based on pharmacological study using an AChE inhibitor. Here we clearly demonstrate plant AChE play an important role as a positive regulator in the gravity response of plants based on a genetic study. First, the gene encoding a second component of the ACh-mediated signal transduction system, AChE was cloned from rice, Oryza sativa L. ssp. Japonica cv. Nipponbare. The rice AChE shared high homology with maize, siratro and Salicornia AChEs. Similar to animal and other plant AChEs, the rice AChE hydrolyzed acetylthiocholine and propionylthiocholine, but not butyrylthiocholine. Thus, the rice AChE might be characterized as an AChE (E.C.3.1.1.7). Similar to maize and siratro AChEs, the rice AChE exhibited low sensitivity to the AChE inhibitor, neostigmine bromide, compared with the electric eel AChE. Next, the functionality of rice AChE was proved by overexpression in rice plants. The rice AChE was localized in extracellular spaces of rice plants. Further, the rice AChE mRNA and its activity were mainly detected during early developmental stages (2 d-10 d after sowing). Finally, by comparing AChE up-regulated plants with wild-type, we found that AChE overexpression causes an enhanced gravitropic response. This result clearly suggests that the function of the rice AChE relate to positive regulation of gravitropic response in rice seedlings. Copyright © 2015 Elsevier Inc. All rights reserved.

Effects of iron deficiency on anisotropy and ferromagnetic resonance linewidth in Bi-doped LiZn ferrite

NASA Astrophysics Data System (ADS)

Jiang, Xiaona; Wang, Wei; Yu, Zhong; Sun, Ke; Lan, Zhongwen; Zhang, Xinran; Harris, Vincent G.

2017-05-01

Bi-doped LiZn ferrites with different iron deficiencies were fabricated by a conventional ceramic method. Anisotropy constant (K1) was calculated and ferromagnetic resonance (FMR) linewidth (ΔH) was investigated. Crystalline anisotropy broadening linewidth (ΔHa) and porosity broadening linewidth (ΔHp) were derived by an approximate calculation based on dipolar narrowing theory, which play a significant role in contributions to FMR linewidth and occupy more than 90 % of ΔH. Physical and static magnetic properties of LiZn ferrite with iron deficiency are presented, which supports a decline in linewidths with increasing iron deficiency. Iron deficiency makes K1, ΔHa and ΔHp reduce. The results also show that ΔHp is the majority of contributions to ΔH in Bi-doped LiZn ferrite and densification is an effective method to decrease ΔH.

Characterization of the endosperm starch and the pleiotropic effects of biosynthetic enzymes on their properties in novel mutant rice lines with high resistant starch and amylose content.

PubMed

Itoh, Yuuki; Crofts, Naoko; Abe, Misato; Hosaka, Yuko; Fujita, Naoko

2017-05-01

Resistant starch (RS) is beneficial to human health. In order to reduce the current prevalence of diabetes and obesity, several transgenic and mutant crops containing high RS content are being developed. RS content of steamed rice with starch-branching enzyme (BE)IIb-deficient mutant endosperms is considerably high. To understand the mechanisms of RS synthesis and to increase RS content, we developed novel mutant rice lines by introducing the gene encoding starch synthase (SS)IIa and/or granule-bound starch synthase (GBSS)I from an indica rice cultivar into a japonica rice-based BEIIb-deficient mutant line, be2b. Introduction of SSIIa from an indica rice cultivar produced higher levels of amylopectin chains with degree of polymerization (DP) 11-18 than those in be2b; the extent of the change was slight due to the shortage of donor chains for SSIIa (DP 6-12) owing to BEIIb deficiency. The introduction of GBSSI from an indica rice cultivar significantly increased amylose content (by approximately 10%) in the endosperm starch. RS content of the new mutant lines was the same as or slightly higher than that of the be2b parent line. The relationship linking starch structure, RS content, and starch biosynthetic enzymes in the new mutant lines has also been discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

Transgenic rice plants harboring an introduced potato proteinase inhibitor II gene are insect resistant.

PubMed

Duan, X; Li, X; Xue, Q; Abo-el-Saad, M; Xu, D; Wu, R

1996-04-01

We introduced the potato proteinase inhibitor II (PINII) gene (pin2) into several Japonica rice varieties, and regenerated a large number of transgenic rice plants. Wound-inducible expression of the pin2 gene driven by its own promoter, together with the first intron of the rice actin 1 gene (act1), resulted in high-level accumulation of the PINII protein in the transgenic plants. The introduced pin2 gene was stably inherited in the second, third, and fourth generations, as shown by molecular analyses. Based on data from the molecular analyses, several homozygous transgenic lines were obtained. Bioassay for insect resistance with the fifth-generation transgenic rice plants showed that transgenic rice plants had increased resistance to a major rice insect pest, pink stem borer (Sesamia inferens). Thus, introduction of an insecticidal proteinase inhibitor gene into cereal plants can be used as a general strategy for control of insect pests.

Selenium and hazardous elements distribution in plant-soil-water system and human health risk assessment of Lower Cambrian, Southern Shaanxi, China.

PubMed

Du, Yajun; Luo, Kunli; Ni, Runxiang; Hussain, Rahib

2018-03-01

The natural selenium poisoning due to toxic Se levels in food chain had been observed in humans and animals in Lower Cambrian outcrop areas in Southern Shaanxi, China. To find out the distribution pattern of selenium and other hazardous elements in the plant, soil and water of Lower Cambrian in Southern Shaanxi, China, and their possible potential health risk, a total of 30 elements were analyzed and the health risk assessment of 18 elements was calculated. Results showed that the soil, plant and natural water of Lower Cambrian all had relatively high Se levels. In Lower Cambrian, the soil was enriched with Se, As, Ba, Cu, Mo, Ni, Zn, Ga, Cd and Cr (1.68 < I geo  < 4.48, I geo ; geo-accumulation index). In same plants, the contents of Se, Cd and Zn (except Cd in corn and rice, Zn in potato and corn) of Lower Cambrian were higher than that of the other strata. Ba and Ga in natural water were higher than that of the other strata, while K and Cs were opposite. The health risk assessment results showed that the people living in outcrop areas of Lower Cambrian had both high total non-carcinogenic risk of 18 elements (HI = 16.12, acceptable range: < 1) and carcinogenic risk of As (3.98E-04, acceptable range: 10 -6 -10 -4 ). High contents of Se, As, Mo and Tl of Lower Cambrian may pose a health risk to local people, and food intake was the major pathway. For minimizing potential health risk, the local inhabitants should use the mix-imported food with local growing foods.

Using iron fertilizer to control Cd accumulation in rice plants: a new promising technology.

PubMed

Shao, GuoSheng; Chen, MingXue; Wang, DanYing; Xu, ChunMei; Mou, RenXiang; Cao, ZhaoYun; Zhang, XiuFu

2008-03-01

Effects of two kinds of iron fertilizer, FeSO4 and EDTA.Na2Fe were studied on cadmium accumulation in rice plants with two rice genotypes, Zhongzao 22 and Zhongjiazao 02, with soil culture systems. The results showed that application of iron fertilizers could hardly make adverse effects on plant growth and rice grain yield. Soil application of EDTA.Na2Fe significantly reduced the Cd accumulation in rice roots, shoots and rice grain. Cd concentration in white rice of both rice genotypes in the treatment of soil application of EDTA.Na2Fe was much lower than 0.2 mg/kg, the maximal Cd permission concentration in cereal crop foods in State standard. However, soil application of FeSO4 or foliar application of FeSO4 or EDTA.Na2Fe resulted in the significant increase of Cd accumulation in rice plants including rice grain compared with the control. The results also showed iron fertilizers increased the concentration of iron, copper and manganese element in rice grain and also affected zinc concentration in plants. It may be a new promising way to regulate Cd accumulation in rice grain in rice production through soil application of EDTA.Na2Fe fertilizers to maintain higher content of available iron and ferrous iron in soils.

Rice microstructure

USDA-ARS?s Scientific Manuscript database

An understanding of plant structure is desirable to obtain a clear idea of the overall impact of a crop. A mature rice plant consists of leafy components (left in the field post-harvest) and paddy rice (collected). The rice plant is supported by a hollow stem (culm) with leaf sheaths attached to nod...

Diabetes-induced hepatic pathogenic damage, inflammation, oxidative stress, and insulin resistance was exacerbated in zinc deficient mouse model.

PubMed

Zhang, Chi; Lu, Xuemian; Tan, Yi; Li, Bing; Miao, Xiao; Jin, Litai; Shi, Xue; Zhang, Xiang; Miao, Lining; Li, Xiaokun; Cai, Lu

2012-01-01

Zinc (Zn) deficiency often occurs in the patients with diabetes. Effects of Zn deficiency on diabetes-induced hepatic injury were investigated. Type 1 diabetes was induced in FVB mice with multiple low-dose streptozotocin. Hyperglycemic and age-matched control mice were treated with and without Zn chelator, N,N,N',N'-tetrakis (2-pyridylemethyl) ethylenediamine (TPEN), at 5 mg/kg body-weight daily for 4 months. Hepatic injury was examined by serum alanine aminotransferase (ALT) level and liver histopathological and biochemical changes. Hepatic Zn deficiency (lower than control level, p<0.05) was seen in the mice with either diabetes or TPEN treatment and more evident in the mice with both diabetes and TPEN. Zn deficiency exacerbated hepatic injuries, shown by further increased serum ALT, hepatic lipid accumulation, inflammation, oxidative damage, and endoplasmic reticulum stress-related cell death in Diabetes/TPEN group compared to Diabetes alone. Diabetes/TPEN group also showed a significant decrease in nuclear factor-erythroid 2-related factor 2 (Nrf2) expression and transcription action along with significant increases in Akt negative regulators, decrease in Akt and GSK-3β phosphorylation, and increase in nuclear accumulation of Fyn (a Nrf2 negative regulator). In vitro study with HepG2 cells showed that apoptotic effect of TPEN at 0.5-1.0 µM could be completely prevented by simultaneous Zn supplementation at the dose range of 30-50 µM. Zn is required for maintaining Akt activation by inhibiting the expression of Akt negative regulators; Akt activation can inhibit Fyn nuclear translocation to export nuclear Nrf2 to cytoplasm for degradation. Zn deficiency significantly enhanced diabetes-induced hepatic injury likely through down-regulation of Nrf2 function.

SOIL CADMIUM AS A THREAT TO HUMAN HEALTH

EPA Science Inventory

Cd contamination of soils has been a public concern since the demonstration that soil Cd from Zn mine wastes which contaminated rice paddies had caused excessive Cd absorption and adverse health effects in members of subsistence farm families who consumed rice grown on the contam...

RiceAtlas, a spatial database of global rice calendars and production.

PubMed

Laborte, Alice G; Gutierrez, Mary Anne; Balanza, Jane Girly; Saito, Kazuki; Zwart, Sander J; Boschetti, Mirco; Murty, M V R; Villano, Lorena; Aunario, Jorrel Khalil; Reinke, Russell; Koo, Jawoo; Hijmans, Robert J; Nelson, Andrew

2017-05-30

Knowing where, when, and how much rice is planted and harvested is crucial information for understanding the effects of policy, trade, and global and technological change on food security. We developed RiceAtlas, a spatial database on the seasonal distribution of the world's rice production. It consists of data on rice planting and harvesting dates by growing season and estimates of monthly production for all rice-producing countries. Sources used for planting and harvesting dates include global and regional databases, national publications, online reports, and expert knowledge. Monthly production data were estimated based on annual or seasonal production statistics, and planting and harvesting dates. RiceAtlas has 2,725 spatial units. Compared with available global crop calendars, RiceAtlas is nearly ten times more spatially detailed and has nearly seven times more spatial units, with at least two seasons of calendar data, making RiceAtlas the most comprehensive and detailed spatial database on rice calendar and production.

Bioengineered 'golden' indica rice cultivars with beta-carotene metabolism in the endosperm with hygromycin and mannose selection systems.

PubMed

Datta, Karabi; Baisakh, Niranjan; Oliva, Norman; Torrizo, Lina; Abrigo, Editha; Tan, Jing; Rai, Mayank; Rehana, Sayda; Al-Babili, Salim; Beyer, Peter; Potrykus, Ingo; Datta, Swapan K

2003-03-01

Vitamin-A deficiency (VAD) is a major malnutrition problem in South Asia, where indica rice is the staple food. Indica-type rice varieties feed more than 2 billion people. Hence, we introduced a combination of transgenes using the biolistic system of transformation enabling biosynthesis of provitamin A in the endosperm of several indica rice cultivars adapted to diverse ecosystems of different countries. The rice seed-specific glutelin promoter (Gt-1 P) was used to drive the expression of phytoene synthase (psy), while lycopene beta-cyclase (lcy) and phytoene desaturase (crtI), fused to the transit peptide sequence of the pea-Rubisco small subunit, were driven by the constitutive cauliflower mosaic virus promoter (CaMV35S P). Transgenic plants were recovered through selection with either CaMV35S P driven hph (hygromycin phosphotransferase) gene or cestrum yellow leaf curling virus promoter (CMP) driven pmi (phophomannose isomerase) gene. Molecular and biochemical analyses demonstrated stable integration and expression of the transgenes. The yellow colour of the polished rice grain evidenced the carotenoid accumulation in the endosperm. The colour intensity correlated with the estimated carotenoid content by spectrophotometric and HPLC analysis. Carotenoid level in cooked polished seeds was comparable (with minor loss of xanthophylls) to that in non-cooked seeds of the same transgenic line. The variable segregation pattern in T1 selfing generation indicated single to multiple loci insertion of the transgenes in the genome. This is the first report of using nonantibiotic pmi driven by a novel promoter in generating transgenic indica rice for possible future use in human nutrition.

Molecular breeding of transgenic rice plants expressing a bacterial chlorocatechol dioxygenase gene.

PubMed

Shimizu, Masami; Kimura, Tetsuya; Koyama, Takayoshi; Suzuki, Katsuhisa; Ogawa, Naoto; Miyashita, Kiyotaka; Sakka, Kazuo; Ohmiya, Kunio

2002-08-01

The cbnA gene encoding the chlorocatechol dioxygenase gene from Ralstonia eutropha NH9 was introduced into rice plants. The cbnA gene was expressed in transgenic rice plants under the control of a modified cauliflower mosaic virus 35S promoter. Western blot analysis using anti-CbnA protein indicated that the cbnA gene was expressed in leaf tissue, roots, culms, and seeds. Transgenic rice calluses expressing the cbnA gene converted 3-chlorocatechol to 2-chloromucote efficiently. Growth and morphology of the transgenic rice plants expressing the cbnA gene were not distinguished from those of control rice plants harboring only a Ti binary vector. It is thus possible to breed transgenic plants that degrade chloroaromatic compounds in soil and surface water.

Effects of zinc deficiency and zinc supplementation on homocysteine levels and related enzyme expression in rats.

PubMed

Jing, Mingyan; Rech, Leslie; Wu, Yinghong; Goltz, Douglas; Taylor, Carla G; House, James D

2015-04-01

Methionine synthase (MS) and betaine-homocysteine methyltransferase (BHMT) are both zinc (Zn)-dependent methyltransferases and involved in the methylation of homocysteine. The objective of this study was to investigate the effects of dietary Zn supply on homocysteine levels and expression of the two enzymes in growing rats. Male weanling Sprague-Dawley rats were assigned randomly to four dietary groups (n=8/group) for 3 weeks: Zn deficient (ZD; <1mg Zn/kg); Zn control (ZC; 30mg Zn/kg); Zn supplemented (ZS; 300mg Zn/kg); pair fed (PF; 30mg Zn/kg) to the ZD group. Serum and femur Zn concentrations were 83% and 58% lower in ZD, and 49% and 62% higher in ZS compared to ZC (P<0.001), respectively. The ZD rats had lower feed intake (37%), body weight gains (45%), liver (43%) and kidney (31%) weights than those of ZC (P<0.001), but these parameters in ZD were not significantly different from the PF controls. Serum homocysteine concentrations were 65% higher in ZD compared to PF (P<0.05), and there was no significant difference in serum folate levels between ZD and PF groups. The mRNA expression of liver and kidney MS was 57% and 38% lower in ZD than PF (P<0.001), respectively. Hepatic and renal BHMT mRNA levels were not altered in ZD compared to controls. The aforementioned measurements were not significantly different between ZS and ZC groups, except Zn levels. These results demonstrated that homocysteine homeostasis appeared to be disturbed by Zn deficiency but not Zn supplementation, and elevated serum homocysteine might be due to reduced expression of MS during Zn deficiency. Copyright © 2014 Elsevier GmbH. All rights reserved.

Protein Biochemistry and Expression Regulation of Cadmium/Zinc Pumping ATPases in the Hyperaccumulator Plants Arabidopsis halleri and Noccaea caerulescens

PubMed Central

Mishra, Seema; Mishra, Archana; Küpper, Hendrik

2017-01-01

P1B-ATPases are decisive for metal accumulation phenotypes, but mechanisms of their regulation are only partially understood. Here, we studied the Cd/Zn transporting ATPases NcHMA3 and NcHMA4 from Noccaea caerulescens as well as AhHMA3 and AhHMA4 from Arabidopsis halleri. Protein biochemistry was analyzed on HMA4 purified from roots of N. caerulescens in active state. Metal titration of NcHMA4 protein with an electrochromic dye as charge indicator suggested that HMA4 reaches maximal ATPase activity when all internal high-affinity Cd2+ binding sites are occupied. Although HMA4 was reported to be mainly responsible for xylem loading of heavy metals for root to shoot transport, the current study revealed high expression of NcHMA4 in shoots as well. Further, there were additional 20 and 40 kD fragments at replete Zn2+ and toxic Cd2+, but not at deficient Zn2+ concentrations. Altogether, the protein level expression analysis suggested a more multifunctional role of NcHMA4 than previously assumed. Organ-level transcription analysis through quantitative PCR of mRNA in N. caerulescens and A. halleri confirmed the strong shoot expression of both NcHMA4 and AhHMA4. Further, in shoots NcHMA4 was more abundant in 10 μM Zn2+ and AhHMA4 in Zn2+ deficiency. In roots, NcHMA4 was up-regulated in response to deficient Zn2+ when compared to replete Zn2+ and toxic Cd2+ treatment. In both species, HMA3 was much more expressed in shoots than in roots, and HMA3 transcript levels remained rather constant regardless of Zn2+ supply, but were up-regulated by 10 μM Cd2+. Analysis of cellular expression by quantitative mRNA in situ hybridisation showed that in A. halleri, both HMA3 and HMA4 mRNA levels were highest in the mesophyll, while in N. caerulescens they were highest in the bundle sheath of the vein. This is likely related to the different final storage sites for hyperaccumulated metals in both species: epidermis in N. caerulescens, mesophyll in A. halleri. PMID:28588597

Protein Biochemistry and Expression Regulation of Cadmium/Zinc Pumping ATPases in the Hyperaccumulator Plants Arabidopsis halleri and Noccaea caerulescens.

PubMed

Mishra, Seema; Mishra, Archana; Küpper, Hendrik

2017-01-01

P 1B -ATPases are decisive for metal accumulation phenotypes, but mechanisms of their regulation are only partially understood. Here, we studied the Cd/Zn transporting ATPases NcHMA3 and NcHMA4 from Noccaea caerulescens as well as AhHMA3 and AhHMA4 from Arabidopsis halleri . Protein biochemistry was analyzed on HMA4 purified from roots of N. caerulescens in active state. Metal titration of NcHMA4 protein with an electrochromic dye as charge indicator suggested that HMA4 reaches maximal ATPase activity when all internal high-affinity Cd 2+ binding sites are occupied. Although HMA4 was reported to be mainly responsible for xylem loading of heavy metals for root to shoot transport, the current study revealed high expression of NcHMA4 in shoots as well. Further, there were additional 20 and 40 kD fragments at replete Zn 2+ and toxic Cd 2+ , but not at deficient Zn 2+ concentrations. Altogether, the protein level expression analysis suggested a more multifunctional role of NcHMA4 than previously assumed. Organ-level transcription analysis through quantitative PCR of mRNA in N. caerulescens and A. halleri confirmed the strong shoot expression of both NcHMA4 and AhHMA4 . Further, in shoots NcHMA4 was more abundant in 10 μM Zn 2+ and AhHMA4 in Zn 2+ deficiency. In roots, NcHMA4 was up-regulated in response to deficient Zn 2+ when compared to replete Zn 2+ and toxic Cd 2+ treatment. In both species, HMA3 was much more expressed in shoots than in roots, and HMA3 transcript levels remained rather constant regardless of Zn 2+ supply, but were up-regulated by 10 μM Cd 2+ . Analysis of cellular expression by quantitative mRNA in situ hybridisation showed that in A. halleri , both HMA3 and HMA4 mRNA levels were highest in the mesophyll, while in N. caerulescens they were highest in the bundle sheath of the vein. This is likely related to the different final storage sites for hyperaccumulated metals in both species: epidermis in N. caerulescens , mesophyll in A. halleri .

Asymmetric Spread of SRBSDV between Rice and Corn Plants by the Vector Sogatella furcifera (Hemiptera: Delphacidae).

PubMed

Li, Pei; Li, Fei; Han, Yongqiang; Yang, Lang; Liao, Xiaolan; Hou, Maolin

2016-01-01

Plant viruses are mostly transmitted by sucking insects via their piercing behaviors, which may differ due to host plant species and their developmental stages. We characterized the transmission of a fijivirus, southern rice black-streaked dwarf virus (SRBSDV), by the planthopper vector Sogatella furcifera Horváth (Hemiptera: Delphacidae), between rice and corn plants of varying developmental stages. SRBSDV was transmitted from infected rice to uninfected corn plants as efficiently as its transmission between rice plants, while was acquired by S. furcifera nymphs at a much lower rate from infected corn plants than from infected rice plants. We also recorded a high mortality of S. furcifera nymphs on corn plants. It is evident that young stages of both the virus donor and recipient plants added to the transmission efficiency of SRBSDV from rice to corn plants. Feeding behaviors of the vector recorded by electrical penetration graph showed that phloem sap ingestion, the behavioral event that is linked with plant virus acquisition, was impaired on corn plants, which accounts for the high mortality of and low virus acquisition by S. furcifera nymphs on corn plants. Our results reveal an asymmetric spread of SRBSDV between its two host plants and the underlying behavioral mechanism, which is of significance for assessing SRBSDV transmission risks and field epidemiology, and for developing integrated management approaches for SRBSDV disease.

Methyl jasmonate induced resistance in cheniere rice and soybean plants

NASA Astrophysics Data System (ADS)

Taplin, C.

2017-12-01

Methyl jasmonate (MJ) is a compound naturally occurring in certain plants that aids in plant defense. In this study, we examined the difference in herbivory of fall armyworm (FAW) on control plants (treated without MJ) and MJ-treated plants. Seeds of cheniere rice and soybean were soaked in MJ overnight and planted in the greenhouse, although the soybean never grew. Therefore, only the mature plant leaves of cheniere rice were fed to FAW and the difference in herbivory was looked at. Our results show there is no statistical difference in the herbivory of the cheniere rice plant leaves.

Dietary rice protein isolate attenuates atherosclerosis in apoE-deficient mice by upregulating antioxidant enzymes

USDA-ARS?s Scientific Manuscript database

Rice-based diets may have been reported to protect against the development of atherosclerosis; however, the underlying mechanism(s) for this protection remains unknown. In this report, the mechanism(s) contributing to the atheroprotective effects of rice-based diet was addressed using the apolipopro...

Downregulation of rice DWARF 14 LIKE suppress mesocotyl elongation via a strigolactone independent pathway in the dark.

PubMed

Kameoka, Hiromu; Kyozuka, Junko

2015-03-20

Strigolactones (SLs) are a class of plant hormones that control plant development in response to environmental conditions. In rice, mesocotyl elongation is regulated by SLs in the dark, while mesocotyls are longer in SL deficient or insensitive mutants. SLs are perceived by DWARF14 (D14), which is a member of a small gene family. In this study, we examined the function of another D14 family gene in rice, D14 LIKE (D14L), focusing on mesocotyl growth. The mesocotyls of D14L RNAi lines are longer than those of WT in the dark. This phenotype is enhanced when the D14L RNAi lines are combined with the d14 mutation, suggesting that D14 and D14L work independently to inhibit mesocotyl elongation. This phenotype is alleviated by the exogenous supply of GR24, a synthetic SL, suggesting that D14L is not necessary for SL signaling. D14L mRNA is predominantly expressed in vascular bundles and crown root primordia. Our results suggest that D14L and D14 confer their effects via an SL independent pathway and an SL signaling pathway respectively. Copyright © 2015 Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and Genetics Society of China. Published by Elsevier Ltd. All rights reserved.

Formin homology 1 (OsFH1) regulates root-hair elongation in rice (Oryza sativa).

PubMed

Huang, Jin; Kim, Chul Min; Xuan, Yuan-hu; Liu, Jingmiao; Kim, Tae Ho; Kim, Bo-Kyeong; Han, Chang-deok

2013-05-01

The outgrowth of root hairs from the epidermal cell layer is regulated by a strict genetic regulatory system and external growth conditions. Rice plants cultivated in water-logged paddy land are exposed to a soil ecology that differs from the environment surrounding upland plants, such as Arabidopsis and maize. To identify genes that play important roles in root-hair growth, a forward genetics approach was used to screen for short-root-hair mutants. A short-root-hair mutant was identified, and the gene was isolated using map-based cloning and sequencing. The mutant harbored a point mutation at a splicing acceptor site, which led to truncation of OsFH1 (rice formin homology 1). Subsequent analysis of two additional T-DNA mutants verified that OsFH1 is important for root-hair elongation. Further studies revealed that the action of OsFH1 on root-hair growth is dependent on growth conditions. The mutant Osfh1 exhibited root-hair defects when roots were grown submerged in solution, and mutant roots produced normal root hairs in the air. However, root-hair phenotypes of mutants were not influenced by the external supply of hormones or carbohydrates, a deficiency of nutrients, such as Fe or P i , or aeration. This study shows that OsFH1 plays a significant role in root-hair elongation in a growth condition-dependent manner.

Effects of silicon on Oryza sativa L. seedling roots under simulated acid rain stress.

PubMed

Ju, Shuming; Yin, Ningning; Wang, Liping; Zhang, Cuiying; Wang, Yukun

2017-01-01

Silicon (Si) has an important function in reducing the damage of environmental stress on plants. Acid rain is a serious abiotic stress factor, and Si can alleviate the stress induced by acid rain on plants. Based on these assumptions, we investigated the effects of silicon on the growth, root phenotype, mineral element contents, hydrogen peroxide (H2O2) and antioxidative enzymes of rice (Oryza sativa L.) seedling roots under simulated acid rain (SAR) stress. The results showed that the combined or single effects of Si and/or SAR on rice roots depend on the concentration of Si and the pH of the SAR. The combined or single effects of a low or moderate concentration of Si (1.0 or 2.0 mM) and light SAR (pH 4.0) enhanced the growth of rice roots, and the combined effects were stronger than those of the single treatment. A high concentration of Si (4.0 mM) or severe SAR (pH 2.0) exerted deleterious effects. The incorporation of Si (1.0, 2.0 or 4.0 mM) into SAR with pH 3.0 or 2.0 promoted the rice root growth, decreased the H2O2 content, increased the Si concentration and the superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX) activities, maintained the balance of mineral element (K, Ca, Mg, Fe, Zn, and Cu) concentrations in the roots of rice seedlings compared with SAR alone. The alleviatory effects observed with a moderate concentration of Si (2.0 mM) were better than the effects obtained with a low or high concentration of Si (1.0 or 4.0 mM). The observed effects were due to disruptions in the absorption and utilization of mineral nutrients and impacts on the activity of antioxidant enzymes in roots, and this conclusion suggests that the degree of rice root damage caused by acid rain might be attributed to not only acid rain but also the level of Si in the soil.

Effects of silicon on Oryza sativa L. seedling roots under simulated acid rain stress

PubMed Central

Wang, Liping; Zhang, Cuiying; Wang, Yukun

2017-01-01

Silicon (Si) has an important function in reducing the damage of environmental stress on plants. Acid rain is a serious abiotic stress factor, and Si can alleviate the stress induced by acid rain on plants. Based on these assumptions, we investigated the effects of silicon on the growth, root phenotype, mineral element contents, hydrogen peroxide (H2O2) and antioxidative enzymes of rice (Oryza sativa L.) seedling roots under simulated acid rain (SAR) stress. The results showed that the combined or single effects of Si and/or SAR on rice roots depend on the concentration of Si and the pH of the SAR. The combined or single effects of a low or moderate concentration of Si (1.0 or 2.0 mM) and light SAR (pH 4.0) enhanced the growth of rice roots, and the combined effects were stronger than those of the single treatment. A high concentration of Si (4.0 mM) or severe SAR (pH 2.0) exerted deleterious effects. The incorporation of Si (1.0, 2.0 or 4.0 mM) into SAR with pH 3.0 or 2.0 promoted the rice root growth, decreased the H2O2 content, increased the Si concentration and the superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX) activities, maintained the balance of mineral element (K, Ca, Mg, Fe, Zn, and Cu) concentrations in the roots of rice seedlings compared with SAR alone. The alleviatory effects observed with a moderate concentration of Si (2.0 mM) were better than the effects obtained with a low or high concentration of Si (1.0 or 4.0 mM). The observed effects were due to disruptions in the absorption and utilization of mineral nutrients and impacts on the activity of antioxidant enzymes in roots, and this conclusion suggests that the degree of rice root damage caused by acid rain might be attributed to not only acid rain but also the level of Si in the soil. PMID:28291806

The influence of bioavailable heavy metals and microbial parameters of soil on the metal accumulation in rice grain.

PubMed

Xiao, Ling; Guan, Dongsheng; Peart, M R; Chen, Yujuan; Li, Qiqi; Dai, Jun

2017-10-01

A field-based study was undertaken to analyze the effects of soil bioavailable heavy metals determined by a sequential extraction procedure, and soil microbial parameters on the heavy metal accumulation in rice grain. The results showed that Cd, Cr, Cu, Ni, Pb and Zn concentrations in rice grain decreases by 65.9%, 78.9%, 32.6%, 80.5%, 61.0% and 15.7%, respectively in the sites 3 (far-away), compared with those in sites 1 (close-to). Redundancy analysis (RDA) indicated that soil catalase activity, the MBC/MBN ratio, along with bioavailable Cd, Cr and Ni could explain 68.9% of the total eigenvalue, indicating that these parameters have a great impact on the heavy metal accumulation in rice grain. The soil bioavailable heavy metals have a dominant impact on their accumulation in rice grain, with a variance contribution of 60.1%, while the MBC/MBN has a regulatory effect, with a variance contribution of 4.1%. Stepwise regression analysis showed that the MBC/MBN, urease and catalase activities are the key microbial parameters that affect the heavy metal accumulation in rice by influencing the soil bioavailable heavy metals or the translocation of heavy metals in rice. RDA showed an interactive effect between Cu, Pb and Zn in rice grain and the soil bioavailable Cd, Cr and Ni. The heavy metals in rice grain, with the exception of Pb, could be predicted by their respective soil bioavailable heavy metals. The results suggested that Pb accumulation in rice grain was mainly influenced by the multi-metal interactive effects, and less affected by soil bioavailable Pb. Copyright © 2017 Elsevier Ltd. All rights reserved.

Purification of contaminated paddy fields by clean water irrigation over two decades.

PubMed

Tai, Yiping; Lu, Huanping; Li, Zhian; Zhuang, Ping; Zou, Bi; Xia, Hanping; Wang, Faming; Wang, Gang; Duan, Jun; Zhang, Jianxia

2013-10-01

Paddy fields near a mining site in north part of Guangdong Province, PR China, were severely contaminated by heavy metals as a result of wastewater irrigation from the tailing pond. The following clean water irrigation for 2 decades produced marked rinsing effect, especially on Pb and Zn. Paddy fields continuously irrigated with wastewater ever since mining started (50 years) had 1,050.0 mg kg−1 of Pb and 810.3 mg kg−1 of Zn for upper 20 cm soil, in comparison with 215.9 mg kg−1 of Pb and 525.4 mg kg−1 of Zn, respectively, with clean water irrigation for 20 years. Rinsing effect mainly occurred to a depth of upper 40 cm, of which the soil contained highest metals. Copper and Cd in the farmlands were also reduced due to clean water irrigation. Higher availability of Pb might partly account for more Pb transferred from the tailing pond to the farmland and also more Pb removal from the farmland as a result of clean water irrigation. Neither rice in the paddy field nor dense weeds in the uncultivated field largely took up the metals. However, they might contribute to activate metals differently, leading to a different purification extent. Rotation of rice and weed reduced metal retention in the farmland soil, in comparison with sole rice growth. Harvesting of rice grain (and partially rice stalk) only contributed small fraction of total amount of removed metal. In summary, heavy metal in paddy field resulting from irrigation of mining wastewater could be largely removed by clean water irrigation for sufficient time.

Improved stress tolerance and productivity in transgenic rice plants constitutively expressing the Oryza sativa glutathione synthetase OsGS under paddy field conditions.

PubMed

Park, Seong-Im; Kim, Young-Saeng; Kim, Jin-Ju; Mok, Ji-Eun; Kim, Yul-Ho; Park, Hyang-Mi; Kim, Il-Sup; Yoon, Ho-Sung

2017-08-01

Reactive oxygen species, which increase under various environmental stresses, have deleterious effects on plants. An important antioxidant, glutathione, is used to detoxify reactive oxygen species in plant cells and is mainly produced by two enzymes: gamma-glutamylcysteine synthetase (γ-ECS) and glutathione synthetase (GS). To evaluate the functional roles of the glutathione synthetase gene (OsGS) in rice, we generated four independent transgenic rice plants (TG1-TG4) that overexpressed OsGS under the control of the constitutively expressed OsCc1 promoter. When grown under natural paddy field conditions, the TG rice plants exhibited greater growth development, higher chlorophyll content, and higher GSH/GSSH ratios than control wild-type (WT) rice plants. Subsequently, the TG rice plants enhanced redox homeostasis by preventing hydroperoxide-mediated membrane damage, which improved their adaptation to environmental stresses. As a result, TG rice plants improved rice grain yield and total biomass following increases in panicle number and number of spikelets per panicle, despite differences in climate during the cultivation periods of 2014 and 2015. Overall, our results indicate that OsGS overexpression improved redox homeostasis by enhancing the glutathione pool, which resulted in greater tolerance to environmental stresses in the paddy fields. Copyright © 2017. Published by Elsevier GmbH.

Inflammation protects copper deficient rats from carbon tetrachloride toxicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, F.L.; Joseph, E.; DiSilvestro, R.A.

1991-03-11

Copper deficient rats show low resistance to CCl{sub 4}, possibly due to low liver Cu-Zn superoxide dismutase (SOD) activities. If Cu-Zn SOD is involved, deficiency effects should be aggravated by inflammation which further lowers Cu-Zn SOD activities in deficient rats. On the contrary, inflammation from 0.1 ml turpentine (im, lef) protected these rats from CCl{sub 4} damage assessed by serum activities of 2 liver enzymes. CCl{sub 4} was given ip at 200 {mu}l/kg, 48 h after turpentine, 24 h before sacrifice. Rats were fed low copper for 40 days before CCl{sub 4} challenge. Inflammation also protected rats fed adequate coppermore » from injury, though injury in noninflamed rats was less than with noninflamed deficients. Protection could result from the large increase observed in liver metallothionein, an induction not restricted by copper deficiency. Alternatively, inflammation may block P-450 activation of CCl{sub 4}. Both explanations are currently under investigation, as is the role, if any, of Cu-Zn SOD in resisting CCl{sub 4} injury.« less

A rice chloroplast transit peptide sequence does not alter the cytoplasmic localization of sheep serotonin N-acetyltransferase expressed in transgenic rice plants.

PubMed

Byeon, Yeong; Lee, Hyoung Yool; Lee, Kyungjin; Back, Kyoungwhan

2014-09-01

Ectopic overexpression of melatonin biosynthetic genes of animal origin has been used to generate melatonin-rich transgenic plants to examine the functional roles of melatonin in plants. However, the subcellular localization of these proteins expressed in the transgenic plants remains unknown. We studied the localization of sheep (Ovis aries) serotonin N-acetyltransferase (OaSNAT) and a translational fusion of a rice SNAT transit peptide to OaSNAT (TS:OaSNAT) in plants. Laser confocal microscopy analysis revealed that both OaSNAT and TS:OaSNAT proteins were localized to the cytoplasm even with the addition of the transit sequence to OaSNAT. Transgenic rice plants overexpressing the TS:OaSNAT fusion transgene exhibited high SNAT enzyme activity relative to untransformed wild-type plants, but lower activity than transgenic rice plants expressing the wild-type OaSNAT gene. Melatonin levels in both types of transgenic rice plant corresponded well with SNAT enzyme activity levels. The TS:OaSNAT transgenic lines exhibited increased seminal root growth relative to wild-type plants, but less than in the OaSNAT transgenic lines, confirming that melatonin promotes root growth. Seed-specific OaSNAT expression under the control of a rice prolamin promoter did not confer high levels of melatonin production in transgenic rice seeds compared with seeds from transgenic plants expressing OaSNAT under the control of the constitutive maize ubiquitin promoter. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Gene flow from transgenic rice to red rice (Oryza sativa L.) in the field.

PubMed

Busconi, M; Baldi, G; Lorenzoni, C; Fogher, C

2014-01-01

In this study, we simulate a transgenic rice crop highly infested with red rice to examine transgene transfer from a transgenic line (A2504) resistant to glufosinate ammonium to cohabitant red rice. The red rice was sown along with the transgenic line at the highest density found in naturally infested crops in the region. Agricultural practices similar to those used to control red rice infestation in northern Italy rice fields were used to reproduce the local rice production system. During the first 2 years, the field was treated with herbicide at the appropriate time; in the first year the dosage of herbicide was three times the recommended amount. In this first year, detectable red rice plants that escaped herbicide treatment were manually removed. Nevertheless, two herbicide-resistant hybrid plants (named 101 and 104) were identified in the experimental field during the second year of cultivation. Phenotypic and molecular characterisation suggests the hybrid nature of these two plants, deriving from crossing events involving A2504, respectively, with red rice (plant 101) and the buffer cultivar Gladio (plant 104). The progeny of two subsequent generations of the two plants were examined and the presence of the transgene detected, indicating stable transfer of the transgene across generations. In conclusion, despite control methods, red rice progeny tolerant to the herbicide can be expected following use of transgenic rice and, consequently, difficulties in controlling this weed with chemicals will emerge in a relatively short time. © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands.

Early-in-life dietary zinc deficiency and supplementation and mammary tumor development in adulthood female rats.

PubMed

da Silva, Flávia R M; Grassi, Tony F; Zapaterini, Joyce R; Bidinotto, Lucas T; Barbisan, Luis F

2017-06-01

Zinc deficiency during pregnancy and postnatal life can adversely increase risk of developing human diseases at adulthood. The present study was designed to evaluate whether dietary zinc deficiency or supplementation during the pregnancy, lactation and juvenile stages interferes in the development of mammary tumors induced by 7,12-dimethylbenzanthracene (DMBA) in female Sprague-Dawley (SD) rats. Pregnant female SD rats were allocated into three groups: zinc-adequate diet (ZnA - 35-mg/kg chow), zinc-deficient diet (ZnD - 3-mg/kg chow) or zinc-supplemented diet (ZnS - 180-mg/kg chow) during gestational day 10 (GD 10) until the litters' weaning. Female offspring received the same diets as their dams until postnatal day (PND) 51. At PND 51, the animals received a single dose of DMBA (50 mg/kg, ig) and zinc-adequate diets. At PND 180, female were euthanized, and tumor samples were processed for histological evaluation and gene expression microarray analysis. The ZnD induced a significant reduction in female offspring body weight evolution and in mammary gland development. At late in life, the ZnD or ZnS did not alter the latency, incidence, multiplicity, volume or histological types of mammary tumors in relation to the ZnA group. However, the total tumor number in ZnS group was higher than in ZnA group, accompanied by distinct expression of 4 genes up- and 15 genes down-regulated. The present findings indicate that early-in-life dietary zinc supplementation, differently to zinc deficiency, has a potential to modify the susceptibility to the development of mammary tumors induced by DMBA. Copyright © 2017 Elsevier Inc. All rights reserved.

Regulation of OsSPL14 by OsmiR156 defines ideal plant architecture in rice.

PubMed

Jiao, Yongqing; Wang, Yonghong; Xue, Dawei; Wang, Jing; Yan, Meixian; Liu, Guifu; Dong, Guojun; Zeng, Dali; Lu, Zefu; Zhu, Xudong; Qian, Qian; Li, Jiayang

2010-06-01

Increasing crop yield is a major challenge for modern agriculture. The development of new plant types, which is known as ideal plant architecture (IPA), has been proposed as a means to enhance rice yield potential over that of existing high-yield varieties. Here, we report the cloning and characterization of a semidominant quantitative trait locus, IPA1 (Ideal Plant Architecture 1), which profoundly changes rice plant architecture and substantially enhances rice grain yield. The IPA1 quantitative trait locus encodes OsSPL14 (SOUAMOSA PROMOTER BINDING PROTEIN-LIKE 14) and is regulated by microRNA (miRNA) OsmiR156 in vivo. We demonstrate that a point mutation in OsSPL14 perturbs OsmiR156-directed regulation of OsSPL14, generating an 'ideal' rice plant with a reduced tiller number, increased lodging resistance and enhanced grain yield. Our study suggests that OsSPL14 may help improve rice grain yield by facilitating the breeding of new elite rice varieties.

The impact of planting date on management of the rice water weevil in Louisiana rice

USDA-ARS?s Scientific Manuscript database

The rice water weevil, Lissorhoptrus oryzophilus, is the most destructive insect pest of rice in the United States. Early planting of rice to avoid damaging infestations of the rice water weevil has long been suggested as a management tactic. A five-year study was conducted to characterize the influ...

Plant architecture and grain yield are regulated by the novel DHHC-type zinc finger protein genes in rice (Oryza sativa L.).

PubMed

Zhou, Bo; Lin, Jian Zhong; Peng, Dan; Yang, Yuan Zhu; Guo, Ming; Tang, Dong Ying; Tan, Xiaofeng; Liu, Xuan Ming

2017-01-01

In many plants, architecture and grain yield are affected by both the environment and genetics. In rice, the tiller is a vital factor impacting plant architecture and regulated by many genes. In this study, we cloned a novel DHHC-type zinc finger protein gene Os02g0819100 and its alternative splice variant OsDHHC1 from the cDNA of rice (Oryza sativa L.), which regulate plant architecture by altering the tiller in rice. The tillers increased by about 40% when this type of DHHC-type zinc finger protein gene was over-expressed in Zhong Hua 11 (ZH11) rice plants. Moreover, the grain yield of transgenic rice increased approximately by 10% compared with wild-type ZH11. These findings provide an important genetic engineering approach for increasing rice yields. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Exogenous superoxide dismutase may lose its antidotal ability on rice leaves

USDA-ARS?s Scientific Manuscript database

Leaf diffusates of the resistant rice cultivars suppressed spore germination of blast fungus (Magnaporthe grisea). Bovine Cu-Zn superoxide dismutase (SOD) added to the diffusate abolished its toxicity. However, the enzyme added to the inoculum did not affect the toxicity of the diffusate. Even the s...

MicroRNA166 Modulates Cadmium Tolerance and Accumulation in Rice.

PubMed

Ding, Yanfei; Gong, Shaohua; Wang, Yi; Wang, Feijuan; Bao, Hexigeduleng; Sun, Junwei; Cai, Chong; Yi, Keke; Chen, Zhixiang; Zhu, Cheng

2018-06-20

MicroRNAs (miRNAs) are 20- to 24-nucleotide small non-coding RNAs that regulate gene expression in eukaryotic organisms. Several plant miRNAs, such as miR166, have vital roles in plant growth, development and responses to environmental stresses. One such environmental stress encountered by crop plants is exposure to cadmium (Cd), an element highly toxic to most organisms, including humans and plants. In this study, we analyzed the role of miR166 in Cd accumulation and tolerance in rice (Oryza sativa). The expression levels of miR166 in both root and leaf tissues were significantly higher in the reproductive stage than in the seedling stage in rice. The expression of miR166 in the roots of rice seedlings was reduced after Cd treatment. Overexpression of miR166 in rice improved Cd tolerance, a result associated with the reduction of Cd-induced oxidative stress in transgenic rice plants. Furthermore, overexpression of miR166 reduced both Cd translocation from roots to shoots and Cd accumulation in the grains. miR166 targets genes encoding the class-III homeodomain-leucine zipper (HD-Zip) family proteins in plants. In rice, HOMEODOMAIN CONTAINING PROTEIN 4 (OsHB4) gene (Os03g43930), which encodes an HD-Zip protein, was up-regulated by Cd treatment but down-regulated by overexpression of miR166 in transgenic rice plants. Overexpression of OsHB4 increased Cd sensitivity and Cd accumulation in the leaves and grains of transgenic rice plants. By contrast, silencing OsHB4 by RNA interference enhanced Cd tolerance in transgenic rice plants. These results indicate a critical role for miR166 in Cd accumulation and tolerance through regulation of its target gene, OsHB4, in rice. {copyright, serif} 2018 American Society of Plant Biologists. All rights reserved.

Gravimorphism in rice and barley: promotion of leaf elongation by vertical inversion in agravitropically growing plants.

PubMed

Abe, K; Takahashi, H; Suge, H

1998-12-01

We have compared shoot responses of agravitropic rice and barley plants to vertical inversion with those of normal ones. When rice plants were vertically inverted, the main stems of a japonica type of rice, cv. Kamenoo, showed negative gravitropism at nodes 2-15 of both elongated and non-elongated internodes. However, shoots of lazy line of rice, lazy-Kamenoo, bent gravitropically at nodes 11-15 only elongated internodes but not at nodes 2-10 of non-elongated ones. Thus, shoots of Kamenoo responded gravitropically at all stages of growth, whereas shoots of lazy-Kamenoo did not show gravitropic response before heading. In Kamenoo plants, lengths of both leaf-sheath and leaf-blade were shortened by vertical inversion, but those of the vertically inverted plants of lazy-Kamenoo were significantly longer than the plants in an upright position. When agravitropic and normal plants of barley were vertically inverted, the same results as in rice were obtained; elongation of both leaf-sheath and leaf-blade was inhibited in normal barley plants, Chikurin-Ibaragi No. 1, but significantly stimulated in agravitropic plants of serpentina barley. These results suggest that vertical inversion of rice and barley plants enhances the elongation growth of leaves in the absence of tropistic response.

Effects and mechanisms of meta-sodium silicate amendments on lead uptake and accumulation by rice.

PubMed

Zhao, Mingliu; Liu, Yuting; Li, Honghong; Cai, Yifan; Wang, Ming Kuang; Chen, Yanhui; Xie, Tuanhui; Wang, Guo

2017-09-01

The objectives of this research were to study the effects of Na 2 SiO 3 application on the uptake, translocation, and accumulation of Pb in rice and to investigate the mechanisms of Pb immobilization by Na 2 SiO 3 in paddy rice soils and rice plants. Pot experiments were conducted using a Cd-Pb-Zn-polluted soil and Oryza sativa L. ssp. indica cv. Donglian 5. L 3 -edge X-ray absorption spectroscopy was used to identify Pb species in soils and roots. The results showed that the application of Na 2 SiO 3 increased soil pH and available soil Si but decreased DTPA-extractable Pb in the soil. High dose of Na 2 SiO 3 (12.5 g/kg) reduced the Pb level in brown rice as it inhibited Pb transfer from soil to rice grains, especially Pb transfer from the root to the stem. The Pb X-ray absorption near-edge spectroscopic analysis revealed that application of high dose of Na 2 SiO 3 increased Pb-ferrihydrite and PbSiO 3 precipitates in the soil and in the root while it reduced Pb-humic acids (Pb-HAs) in the soil and Pb-pectin in the root. The decrease in Pb availability in the soil can be partly attributed to increase the precipitation of PbSiO 3 and the association of Pb 2+ with Fe oxides in the soil. The inhibition of the root-to-stem translocation of Pb was partially due to the precipitation of PbSiO 3 on the root surfaces or inside the roots.

Studies on the Ecological Adaptability of Growing Rice with Floating Bed on the Dilute Biogas Slurry

PubMed Central

Du, Qi; Cheng, Bowen; Liao, Zhiqi; Sun, Chengcheng

2016-01-01

This study aimed to explore the ecological adaptability and the possibility of growing rice with floating bed on the dilute biogas slurry. The results of the experiments show that the growth stage, rice plant height, and rice yield and quality were significantly affected by multiple dilutions; rice plants cultivated with 45 multiple dilutions had better ecological adaptability than others. In the 45 multiple dilutions' group, the yield of rice was 13.3 g/bucket (8 rice plants), milled rice rate was 63.1%, and the content of crude protein in the rice was 6.3%. The concentrations of heavy metals in the rice cultivated with 30 multiple dilutions' slurry, such as total lead, cadmium, mercury, chromium, and arsenic, were all below the national standard. The study shows that it is possible and safe to cultivate rice plants with no soil but diluted biogas slurry. In the experiments, the yield, milled rice rate, and crude protein of the rice cultivated with slurry were not as much as those of rice cultivated with regular way in soil. This study provides the basic theoretical support for the development of biogas projects and the potential achievement of organic farming in special agricultural facilities and circular economy. PMID:27882324

Field trial of GABA-fortified rice plants and oral administration of milled rice in spontaneously hypertensive rats.

PubMed

Kowaka, Emi; Shimajiri, Yasuka; Kawakami, Kouhei; Tongu, Miki; Akama, Kazuhito

2015-06-01

Hypertension is one of the most critical risk factors accompanying cardiovascular diseases. γ-Aminobutyric acid (GABA) is a non-protein amino acid that functions as a major neurotransmitter in mammals and also as a blood-pressure lowering agent. We previously produced GABA-fortified rice lines of a popular Japonica rice cultivar 'Koshihikari' by genetic manipulation of GABA shunt-related genes. In the study reported here, we grew these same novel rice lines in a field trial and administered the milled rice orally to rats. The yield parameters of the transgenic rice plants were almost unchanged compared to those of untransformed cv. 'Koshihikari' plants, while the rice grains of the transgenic plants contained a high GABA content (3.5 g GABA/kg brown rice; 0.75-0.85 GABA g/kg milled rice) in a greenhouse trial. Oral administration of a diet containing 2.5% GABA-fortified rice, with a daily intake for 8 weeks, had an approximately 20 mmHg anti-hypertensive effect in spontaneous hypertensive rats but not in normotensive Wistar-Kyoto rats. These results suggest that GABA-fortified rice may be applicable as a staple food to control or prevent hypertension.

Essential and Beneficial Trace Elements in Plants, and Their Transport in Roots: a Review.

PubMed

Vatansever, Recep; Ozyigit, Ibrahim Ilker; Filiz, Ertugrul

2017-01-01

The essentiality of 14 mineral elements so far have been reported in plant nutrition. Eight of these elements were known as micronutrients due to their lower concentrations in plants (usually ≤100 mg/kg/dw). However, it is still challenging to mention an exact number of plant micronutrients since some elements have not been strictly proposed yet either as essential or beneficial. Micronutrients participate in very diverse metabolic processes, including from the primary and secondary metabolism to the cell defense, and from the signal transduction to the gene regulation, energy metabolism, and hormone perception. Thus, the attempt to understand the molecular mechanism(s) behind their transport has great importance in terms of basic and applied plant sciences. Moreover, their deficiency or toxicity also caused serious disease symptoms in plants, even plant destruction if not treated, and many people around the world suffer from the plant-based dietary deficiencies or metal toxicities. In this sense, shedding some light on this issue, the 13 mineral elements (Fe, B, Cu, Mn, Mo, Si, Zn, Ni, Cl, Se, Na, Al, and Co), required by plants at trace amounts, has been reviewed with the primary focus on the transport proteins (transporters/channels) in plant roots. So, providing the compiled but extensive information about the structural and functional roles of micronutrient transport genes/proteins in plant roots.

PAY1 improves plant architecture and enhances grain yield in rice.

PubMed

Zhao, Lei; Tan, Lubin; Zhu, Zuofeng; Xiao, Langtao; Xie, Daoxin; Sun, Chuanqing

2015-08-01

Plant architecture, a complex of the important agronomic traits that determine grain yield, is a primary target of artificial selection of rice domestication and improvement. Some important genes affecting plant architecture and grain yield have been isolated and characterized in recent decades; however, their underlying mechanism remains to be elucidated. Here, we report genetic identification and functional analysis of the PLANT ARCHITECTURE AND YIELD 1 (PAY1) gene in rice, which affects plant architecture and grain yield in rice. Transgenic plants over-expressing PAY1 had twice the number of grains per panicle and consequently produced nearly 38% more grain yield per plant than control plants. Mechanistically, PAY1 could improve plant architecture via affecting polar auxin transport activity and altering endogenous indole-3-acetic acid distribution. Furthermore, introgression of PAY1 into elite rice cultivars, using marker-assisted background selection, dramatically increased grain yield compared with the recipient parents. Overall, these results demonstrated that PAY1 could be a new beneficial genetic resource for shaping ideal plant architecture and breeding high-yielding rice varieties. © 2015 The Authors The Plant Journal published by Society for Experimental Biology and John Wiley & Sons Ltd.

Multiple micronutrient-fortified rice affects physical performance and plasma vitamin B-12 and homocysteine concentrations of Indian school children.

PubMed

Thankachan, Prashanth; Rah, Jee Hyun; Thomas, Tinku; Selvam, Sumithra; Amalrajan, Vani; Srinivasan, Krishnamachari; Steiger, Georg; Kurpad, Anura V

2012-05-01

Fortifying rice with multiple micronutrients could be a promising strategy for combat micronutrient deficiencies in developing countries. We determined the efficacy of extruded rice grains fortified with multiple micronutrients on the prevalence of anemia, micronutrient status, and physical and cognitive performance in 6- to 12-y-old, low-income school children in Bangalore, India. In a randomized, double-blind, controlled trial, 258 children were assigned to 1 of 3 intervention groups to receive rice-based lunch meals fortified with multiple micronutrients with either low-iron (6.25 mg) or high-iron (12.5 mg) concentrations or identical meals with unfortified rice. The meals were provided 6 d/wk for 6 mo. Anthropometric, biochemical, physical performance, and cognitive assessments were taken at baseline and endpoint. At baseline, study groups were comparable, with 61% of the children being anemic. However, only <10% were deficient in iron, vitamin A, and zinc. After 6 mo, plasma vitamin B-12 and homocysteine concentrations (both P < 0.001) as well as physical performance (P < 0.05) significantly improved in the intervention arms. No between-group differences were observed in hemoglobin concentration, anemia, and deficiencies of other micronutrients or cognitive function after 6 mo, but paired analyses revealed a small reduction in anemia prevalence in children in the low-iron group. The fortified rice was efficacious in improving vitamin B-12 status and physical performance in Indian school children.

Comparison of Ion Balance and Nitrogen Metabolism in Old and Young Leaves of Alkali-Stressed Rice Plants

PubMed Central

Wang, Huan; Wu, Zhihai; Han, Jiayu; Zheng, Wei; Yang, Chunwu

2012-01-01

Background Alkali stress is an important agricultural contaminant and has complex effects on plant metabolism. The aim of this study was to investigate whether the alkali stress has different effects on the growth, ion balance, and nitrogen metabolism in old and young leaves of rice plants, and to compare functions of both organs in alkali tolerance. Methodology/Principal Findings The results showed that alkali stress only produced a small effect on the growth of young leaves, whereas strongly damaged old leaves. Rice protected young leaves from ion harm via the large accumulation of Na+ and Cl− in old leaves. The up-regulation of OsHKT1;1, OsAKT1, OsHAK1, OsHAK7, OsHAK10 and OsHAK16 may contribute to the larger accumulation of Na+ in old leaves under alkali stress. Alkali stress mightily reduced the NO3 − contents in both organs. As old leaf cells have larger vacuole, under alkali stress these scarce NO3 − was principally stored in old leaves. Accordingly, the expression of OsNRT1;1 and OsNRT1;2 in old leaves was up-regulated by alkali stress, revealing that the two genes might contribute to the accumulation of NO3 − in old leaves. NO3 − deficiency in young leaves under alkali stress might induce the reduction in OsNR1 expression and the subsequent lacking of NH4 +, which might be main reason for the larger down-regulation of OsFd-GOGAT and OsGS2 in young leaves. Conclusions/Significance Our results strongly indicated that, during adaptation of rice to alkali stress, young and old leaves have distinct mechanisms of ion balance and nitrogen metabolism regulation. We propose that the comparative studies of young and old tissues may be important for abiotic stress tolerance research. PMID:22655071

Characterization of cadmium-resistant bacteria and their potential for reducing accumulation of cadmium in rice grains.

PubMed

Lin, Xiaoyan; Mou, Renxiang; Cao, Zhaoyun; Xu, Ping; Wu, Xiaoliang; Zhu, Zhiwei; Chen, Mingxue

2016-11-01

Cadmium (Cd) pollution is a serious widespread environmental problem that not only destroys the microbial ecology of soil and decreases crop production, but also poses a serious risk to human health. Many methods have been used for the remediation of Cd pollution but none of these is totally satisfactory. Microbial remediation strategies have attracted increasing interest since they are environmentally friendly and cost-effective. In the present study, three Cd-resistant bacteria were isolated and evaluated for potential application in Cd bioremediation. Based on their morphological, physiological and biochemical characteristics, together with 16S rDNA gene sequence analyses, bacteria were identified as Stenotrophomonas acidaminiphila (2#), Pseudomonas aeruginosa (9#) and Delftia tsuruhatensis (12#). Pseudomonas aeruginosa showed very high tolerance to metals, especially Cd (2200mg/L), Zn (1800mg/L) and Pb (1200mg/L), and is thought to be a multi-metal-resistant bacterium. Pseudomonas aeruginosa was also sensitive to 13 different antibiotics. The effects of the bacterial strains on the growth of rice plants and their ability to reduce Cd accumulation from Cd-contaminated soils in pot experiments were also evaluated. For Oryza sativa L. A grown in contaminated soil (3mg/kg Cd), the accumulation of Cd was decreased by 31.2 and 25.5% in brown rice and polished rice, respectively, by strain 9#; Pseudomonas aeruginosa was more effective in reducing Cd accumulation in rice grains than a mixture of strains. For Oryza sativa L. B, a mixture of strains acting synergistically was more effective than a single strain in reducing Cd accumulation; treatment with mixed strains (strains+3mg/kg Cd) resulted in 41.3, 35.9, and 32.6% reductions in Cd accumulation in unhulled rice, brown rice and polished rice, respectively. Although different results were obtained for two rice varieties, it can still be concluded that Cd-resistant bacteria are suitable for reducing Cd accumulation in rice grains and show potential for bioremediation of Cd-contaminated soils. Copyright © 2016 Elsevier B.V. All rights reserved.

Cold Extrusion but Not Coating Affects Iron Bioavailability from Fortified Rice in Young Women and Is Associated with Modifications in Starch Microstructure and Mineral Retention during Cooking.

PubMed

Hackl, Laura; Speich, Cornelia; Zeder, Christophe; Sánchez-Ferrer, Antoni; Adelmann, Horst; de Pee, Saskia; Tay, Fabian; Zimmermann, Michael B; Moretti, Diego

2017-12-01

Background: Rice can be fortified with the use of hot or cold extrusion or coating, but the nutritional qualities of the resulting rice grains have never been directly compared. Objective: Using fortified rice produced by coating or hot or cold extrusion, we compared 1 ) iron and zinc absorption with the use of stable isotopes, 2 ) iron and zinc retention during cooking, and 3 ) starch microstructure. Methods: We conducted 2 studies in young women: in study 1 [ n = 19; mean ± SD age: 26.2 ± 3.4 y; body mass index (BMI; in kg/m 2 ): 21.3 ± 1.6], we compared the fractional iron absorption (FAFe) from rice meals containing isotopically labeled ferric prophosphate ( 57 FePP), zinc oxide (ZnO), citric acid, and micronutrients fortified through hot extrusion (HER1) with rice meals fortified through cold extrusion containing 57 FePP, ZnO, citric acid, and micronutrients (CER); in study 2 ( n = 22; age: 24 ± 4 y; BMI: 21.2 ± 1.3), we compared FAFe and fractional zinc absorption (FAZn) from rice meals fortified through hot extrusion (HER2) compared with rice meals fortified through coating containing 57 FePP, ZnO, a citric acid and trisodium cirate mixture (CA/TSC), and micronutrients (COR) relative to rice meals extrinsically fortified with ferrous sulfate (reference). Rice types HER1 and CER contained citric acid, whereas types HER2 and COR contained CA/TSC. We assessed retention during standardized cooking experiments and characterized the rice starch microstructure. Results: FAFe (95% CI) was greater from CER [2.2% (1.4%, 3.4%)] than from HER1 [1.2% (0.7%, 2.0%)] ( P = 0.036). There was no difference in FAFe between HER2 [5.1% (3.7%, 7.1%)] and COR [4.0% (2.9%, 5.4%)] ( P = 0.14), but FAFe from COR was lower than that from the reference meal [6.6% (4.9%, 9.0%)] ( P = 0.003), and the geometric mean FAZn (95% CI) did not differ between HER2 [9.5% (7.9%, 11.6%)] and COR [9.6% (8.7%, 10.7%)] ( P = 0.92). Cooking in a rice-to-water ratio of 1:2 resulted in iron and zinc retentions >80%, and cooking in excess water did not affect iron retention from hot-extruded rice but caused iron losses of 25% from CER and COR. Distinct variations in starch microstructure were found in CER and HER1. Conclusions: Iron absorption was 64% higher from CER than from hot-extruded rice, with no difference between COR compared with hot-extruded rice. Lower extrusion temperatures may generate a more readily digestible starch structure, allowing for greater iron release in vivo but lower mineral retention during cooking. This trial was registered at clinicaltrials.gov as NCT02176759. © 2017 American Society for Nutrition.

Estimated Effects of Future Atmospheric CO2 Concentrations on Protein Intake and the Risk of Protein Deficiency by Country and Region

PubMed Central

Schwartz, Joel; Myers, Samuel S.

2017-01-01

Background: Crops grown under elevated atmospheric CO2 concentrations (eCO2) contain less protein. Crops particularly affected include rice and wheat, which are primary sources of dietary protein for many countries. Objectives: We aimed to estimate global and country-specific risks of protein deficiency attributable to anthropogenic CO2 emissions by 2050. Methods: To model per capita protein intake in countries around the world under eCO2, we first established the effect size of eCO2 on the protein concentration of edible portions of crops by performing a meta-analysis of published literature. We then estimated per-country protein intake under current and anticipated future eCO2 using global food balance sheets (FBS). We modeled protein intake distributions within countries using Gini coefficients, and we estimated those at risk of deficiency from estimated average protein requirements (EAR) weighted by population age structure. Results: Under eCO2, rice, wheat, barley, and potato protein contents decreased by 7.6%, 7.8%, 14.1%, and 6.4%, respectively. Consequently, 18 countries may lose >5% of their dietary protein, including India (5.3%). By 2050, assuming today’s diets and levels of income inequality, an additional 1.6% or 148.4 million of the world’s population may be placed at risk of protein deficiency because of eCO2. In India, an additional 53 million people may become at risk. Conclusions: Anthropogenic CO2 emissions threaten the adequacy of protein intake worldwide. Elevated atmospheric CO2 may widen the disparity in protein intake within countries, with plant-based diets being the most vulnerable. https://doi.org/10.1289/EHP41 PMID:28885977

Effect of volunteer rice infestation on grain quality and yield of rice

USDA-ARS?s Scientific Manuscript database

Volunteer rice (Oryza sativa L.) plants arise from shattered seeds of the previous crop, which could reduce the yield of cultivated rice and the commercial value of harvested grain. Volunteer rice plants from a cultivar other than the current crop produce grains that may differ in physico-chemical t...

Enhanced disease resistance and drought tolerance in transgenic rice plants overexpressing protein elicitors from Magnaporthe oryzae.

PubMed

Wang, Zhenzhen; Han, Qiang; Zi, Qian; Lv, Shun; Qiu, Dewen; Zeng, Hongmei

2017-01-01

Exogenous application of the protein elicitors MoHrip1 and MoHrip2, which were isolated from the pathogenic fungus Magnaporthe oryzae (M. oryzae), was previously shown to induce a hypersensitive response in tobacco and to enhance resistance to rice blast. In this work, we successfully transformed rice with the mohrip1 and mohrip2 genes separately. The MoHrip1 and MoHrip2 transgenic rice plants displayed higher resistance to rice blast and stronger tolerance to drought stress than wild-type (WT) rice and the vector-control pCXUN rice. The expression of salicylic acid (SA)- and abscisic acid (ABA)-related genes was also increased, suggesting that these two elicitors may trigger SA signaling to protect the rice from damage during pathogen infection and regulate the ABA content to increase drought tolerance in transgenic rice. Trypan blue staining indicated that expressing MoHrip1 and MoHrip2 in rice plants inhibited hyphal growth of the rice blast fungus. Relative water content (RWC), water usage efficiency (WUE) and water loss rate (WLR) were measured to confirm the high capacity for water retention in transgenic rice. The MoHrip1 and MoHrip2 transgenic rice also exhibited enhanced agronomic traits such as increased plant height and tiller number.

Application of biosolids in mineral sands mine rehabilitation: use of stockpiled topsoil decreases trace element uptake by plants.

PubMed

Rate, Andrew W; Lee, Karen M; French, Peter A

2004-02-01

Mineral sands mining involves stripping topsoil to access heavy-mineral bearing deposits, which are then rehabilitated to their original state, commonly pasture in south-west Western Australia. Organic amendments such as biosolids (digested sewage sludge) can contribute organic carbon to the rehabilitating system and improve soil chemical fertility and physical conditions. Use of biosolids also introduces the risk of contamination of the soil-plant system with heavy metals, but may be a useful source of trace elements to plants if the concentrations of these elements are low in unamended soil. We expected that biosolids amendment of areas mined for mineral sands would result in increased concentrations of metals in soils and plants, and that metal uptake would be decreased by adding stockpiled topsoil or by liming. A glasshouse experiment growing a mixed annual ryegrass (Lolium rigidum)-subterranean clover (Trifolium subterraneum) sward was conducted using two soil materials (residue sand/clay and conserved topsoil) from a mineral sands mine amended with different rates of biosolids (0, 10, 20, 50 dry t/ha), and including a liming treatment (2 t/ha). Total concentrations of metals (As, Cd, Co, Cr, Cu, Ni, Pb and Zn) in soil increased with increasing rate of biosolids application. Metal uptake was generally lower where topsoil was present and was decreased by liming. With increasing biosolids application, plant metal concentrations increased for Cd, Ni and Zn but decreased or were erratic for other elements. In clover, biosolids application removed the Zn deficiency observed where biosolids were not applied. Plant uptake of all elements increased with increasing biosolids application, suggesting dilution by increased plant biomass was responsible for erratic metal concentration results. Despite the observed increases in uptake of metals by plants, metal concentrations in both species were low and below food standard thresholds. It is unlikely that a single application of biosolids in this system posed a threat from heavy metal contamination of soils or plants, and was beneficial in terms of Zn nutrition of T. subterraneum.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Euan; Kempson, Ivan; Juhasz, Albert L.

The consumption of arsenic (As) contaminated rice is an important exposure route for humans in countries where rice cultivation employs As contaminated irrigation water. Arsenic toxicity and mobility are a function of its chemical-speciation. The distribution and identification of As in the rice plant are hence necessary to determine the uptake, transformation and potential risk posed by As contaminated rice. In this study we report on the distribution and chemical-speciation of As in rice (Oryza sativa Quest) by X-ray fluorescence (XRF) and X-ray absorption near edge structure (XANES) measurements of rice plants grown in As contaminated paddy water. Investigations ofmore » {mu}XRF images from rice tissues found that As was present in all rice tissues, and its presence correlated with the presence of iron at the root surface and copper in the rice leaf. X-ray absorption near edge structure analysis of rice tissues identified that inorganic As was the predominant form of As in all rice tissues studied, and that arsenite became increasingly dominant in the aerial portion of the rice plant.« less

Bacillomycin L and surfactin contribute synergistically to the phenotypic features of Bacillus subtilis 916 and the biocontrol of rice sheath blight induced by Rhizoctonia solani.

PubMed

Luo, Chuping; Zhou, Huafei; Zou, Jincheng; Wang, Xiaoyu; Zhang, Rongsheng; Xiang, Yaping; Chen, Zhiyi

2015-02-01

The antagonistic activity of lipopeptides in Bacillus subtilis 916 has been well documented, yet relatively little is known about their mechanism in biofilm formation and environmental colonization. This study sought to examine the interaction of B. subtilis 916 on Rhizoctonia solani-infected rice sheath to elucidate the mechanism of colonization on plant leaves. Results showed that the mutants Δbac, Δsrf, and Δsrf + bac of B. subtilis 916, deficient in bacillomycin L and surfactin production, respectively, not only altered colony morphology but also changed swarming motility, reduced antagonistic activity, and decreased biofilm formation. In particular, biofilm formation in mutant Δbac, not Δsrf or Δsrf + bac, were restored with addition of surfactin and bacillomycin L at 10 and 50 μg/mL, respectively. Moreover, surfactin and bacillomycin L were able to restore or enhance swarming motility in the corresponding mutants at 10 μg/mL, respectively. With the aid of green fluorescent protein tagging, it was demonstrated that B. subtilis 916 formed a robust biofilm on the rice sheath blight lesion and colonized well on R. solani-infected rice sheath, while its corresponding mutants performed poorly. These observations also correlated with the rice cultivar pot experiments, in which B. subtilis 916 exhibited greater biocontrol than its mutants. Our results suggest that surfactin and bacillomycin L contribute differently but synergistically to the biocontrol of rice sheath blight in B. subtilis 916 through its antifungal activity, biofilm formation, and colonization.

The tillering phenotype of the rice plastid terminal oxidase (PTOX) loss-of-function mutant is associated with strigolactone deficiency.

PubMed

Tamiru, Muluneh; Abe, Akira; Utsushi, Hiroe; Yoshida, Kakoto; Takagi, Hiroki; Fujisaki, Koki; Undan, Jerwin R; Rakshit, Sujay; Takaichi, Shinichi; Jikumaru, Yusuke; Yokota, Takao; Terry, Matthew J; Terauchi, Ryohei

2014-04-01

The significance of plastid terminal oxidase (PTOX) in phytoene desaturation and chloroplast function has been demonstrated using PTOX-deficient mutants, particularly in Arabidopsis. However, studies on its role in monocots are lacking. Here, we report cloning and characterization of the rice (Oryza sativa) PTOX1 gene. Using Ecotype Targeting Induced Local Lesions IN Genomes (EcoTILLING) and TILLING as forward genetic tools, we identified the causative mutation of an EMS mutant characterized by excessive tillering, semi-dwarfism and leaf variegation that corresponded to the PTOX1 gene. The tillering and semi-dwarf phenotypes of the ptox1 mutant are similar to phenotypes of known strigolactone (SL)-related rice mutants, and both phenotypic traits could be rescued by application of the synthetic SL GR24. The ptox1 mutant accumulated phytoene in white leaf sectors with a corresponding deficiency in β-carotene, consistent with the expected function of PTOX1 in promoting phytoene desaturase activity. There was also no accumulation of the carotenoid-derived SL ent-2'-epi-5-deoxystrigol in root exudates. Elevated concentrations of auxin were detected in the mutant, supporting previous observations that SL interaction with auxin is important in shoot branching control. Our results demonstrate that PTOX1 is required for both carotenoid and SL synthesis resulting in SL-deficient phenotypes in rice. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Superior Root Hair Formation Confers Root Efficiency in Some, But Not All, Rice Genotypes upon P Deficiency.

PubMed

Nestler, Josefine; Wissuwa, Matthias

2016-01-01

Root hairs are a low-cost way to extend root surface area (RSA), water and nutrient acquisition. This study investigated to what extend variation exists for root hair formation in rice in dependence of genotype, phosphorus (P) supply, growth medium, and root type. In general, genotypic variation was found for three root hair properties: root hair length, density, and longevity. In low P nutrient solution more than twofold genotypic difference was detected for root hair length while only onefold variation was found in low P soil. These differences were mostly due to the ability of some genotypes to increase root hair length in response to P deficiency. In addition, we were able to show that a higher proportion of root hairs remain viable even in mature, field-grown plants under low P conditions. All investigated root hair parameters exhibited high correlations across root types which were always higher in the low P conditions compared to the high P controls. Therefore we hypothesize that a low P response leads to a systemic signal in the entire root system. The genotype DJ123 consistently had the longest root hairs under low P conditions and we estimated that, across the field-grown root system, root hairs increased the total RSA by 31% in this genotype. This would explain why DJ123 is considered to be very root efficient in P uptake and suggests that DJ123 should be utilized as a donor in breeding for enhanced P uptake. Surprisingly, another root and P efficient genotype seemed not to rely on root hair growth upon P deficiency and therefore must contain different methods of low P adaptation. Genotypic ranking of root hair properties did change substantially with growth condition highlighting the need to phenotype plants in soil-based conditions or at least to validate results obtained in solution-based growth conditions.

Development of a certified reference material (NMIJ CRM 7531-a) for the determination of trace cadmium and other elements in brown rice flour.

PubMed

Miyashita, Shin-ichi; Inagaki, Kazumi; Narukawa, Tomohiro; Zhu, Yanbei; Kuroiwa, Takayoshi; Hioki, Akiharu; Chiba, Koichi

2012-01-01

A certified reference material (CRM) for trace cadmium and other elements in brown rice flour was developed at the National Metrology Institute of Japan (NMIJ). The CRM was provided as a dry powder after drying and frozen pulverization of fresh brown rice obtained from a Japanese domestic market. Characterization of the property value for each element was carried out exclusively by NMIJ with at least two independent analytical methods, including inductively coupled plasma mass spectrometry (ICP-MS), ICP high-resolution mass spectrometry, isotope-dilution ICP-MS, ICP optical emission spectrometry, and graphite-furnace atomic-absorption spectrometry. Property values were provided for six elements (Mn, Fe, Cu, Zn, As, and Cd). The concentration range of the property values was from 0.280 mg kg(-1) of As to 31.8 mg kg(-1) of Zn. The combined relative standard uncertainties of the property values were estimated by considering the uncertainties of the homogeneity, characterization, difference among analytical methods, dry-mass correction factor, and calibration standard. The range of the relative combined standard uncertainties was from 1.1% of Zn to 1.6% of As.

Zinc transporter 3 is involved in learned fear and extinction, but not in innate fear.

PubMed

Martel, Guillaume; Hevi, Charles; Friebely, Olivia; Baybutt, Trevor; Shumyatsky, Gleb P

2010-11-01

Synaptically released Zn²+ is a potential modulator of neurotransmission and synaptic plasticity in fear-conditioning pathways. Zinc transporter 3 (ZnT3) knock-out (KO) mice are well suited to test the role of zinc in learned fear, because ZnT3 is colocalized with synaptic zinc, responsible for its transport to synaptic vesicles, highly enriched in the amygdala-associated neural circuitry, and ZnT3 KO mice lack Zn²+ in synaptic vesicles. However, earlier work reported no deficiency in fear memory in ZnT3 KO mice, which is surprising based on the effects of Zn²+ on amygdala synaptic plasticity. We therefore reexamined ZnT3 KO mice in various tasks for learned and innate fear. The mutants were deficient in a weak fear-conditioning protocol using single tone-shock pairing but showed normal memory when a stronger, five-pairing protocol was used. ZnT3 KO mice were deficient in memory when a tone was presented as complex auditory information in a discontinuous fashion. Moreover, ZnT3 KO mice showed abnormality in trace fear conditioning and in fear extinction. By contrast, ZnT3 KO mice had normal anxiety. Thus, ZnT3 is involved in associative fear memory and extinction, but not in innate fear, consistent with the role of synaptic zinc in amygdala synaptic plasticity.

Transpiration rates of rice plants treated with Trichoderma spp.

NASA Astrophysics Data System (ADS)

Doni, Febri; Anizan, I.; Che Radziah C. M., Z.; Yusoff, Wan Mohtar Wan

2014-09-01

Trichoderma spp. are considered as successful plant growth promoting fungi and have positive role in habitat engineering. In this study, the potential for Trichoderma spp. to regulate transpiration process in rice plant was assessed experimentally under greenhouse condition using a completely randomized design. The study revealed that Trichoderma spp. have potential to enhance growth of rice plant through transpirational processes. The results of the study add to the advancement of the understanding as to the role of Trichoderma spp. in improving rice physiological process.

Selective mimics of strigolactone actions and their potential use for controlling damage caused by root parasitic weeds.

PubMed

Fukui, Kosuke; Ito, Shinsaku; Asami, Tadao

2013-01-01

Strigolactones (SLs) are a novel class of plant hormones and rhizosphere communication signals, although the molecular mechanisms underlying their activities have not yet been fully determined. Nor is their application in agriculture well developed. The importance of plant hormone agonists has been demonstrated in both basic and applied research, and chemicals that mimic strigolactone functions should greatly facilitate strigolactone research. Here, we report our discovery of a new phenoxyfuranone compound, 4-Br debranone (4BD), that shows similar activity to that of the major strigolactone (SL) analog GR24 in many aspects of a biological assay on plants. 4BD strongly inhibited tiller bud outgrowth in the SL-deficient rice mutant d10 at the same concentration as GR24, with no adverse effects, even during prolonged cultivation. This result was also observed in the Arabidopsis thaliana SL-deficient mutants max1, max3, and max4. However, the application of 4BD to the Arabidopsis SL-insensitive mutant max2 induced no morphological changes in it. The expression of SL biosynthetic genes was also reduced by 4BD treatment, probably via negative feedback regulation. However, in a seed germination assay on Striga hermonthica, a root parasitic plant, 4BD showed far less activity than GR24. These results suggest that 4BD is the first plant-specific strigolactone mimic.

Calcium deficiency and CaCO/sub 3/ on micronutrient status of plants grown in solution culture. [Lycopersicon esculentum, Phaseolus vulgaris

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wallace, A.; Cha, J.W.; Alexander, G.V.

Plants were grown in solution culture with different levels of Ca to further evaluate Ca relationships to trace metal uptake and to toxicity of trace metals. When tomato plants (Lycopersicon esculentum L., Tropic) were grown at a low level of Ca, the Zn, Cu, Fe, Mn, Al, and Ti concentrations of leaves, stems, and roots were considerably increased. The use of an excess of CaCO/sub 3/ which increased pH did not influence the trace metal concentrations of plants any more than did Ca/sup + +/. In a factorial experiment with bush beans (Phaseolus vulgaris L. C.V. Improved Tendergreen) with Camore » (10/sup -4/, 10/sup -2/, 10/sup -2/N) and Ni (0, 2 x 10/sup -6/ M, 2 x 10/sup -5/ M), Ni phytotoxicity and Ni uptake were decreased somewhat at the highest Ca level. High Ni tended to decrease the Ca concentration in leaves. High Ca and Ni both tended to decrease Fe, Cu, Zn, and Mn concentrations in leaves. The Ni had some interactions on the P concentrations of shoots.« less

Influence of rice black streaked dwarf virus on the ecological fitness of non-vector planthopper Nilaparvata lugens (Hemiptera: Delphacidae).

PubMed

Xu, Hong-Xing; He, Xiao-Chan; Zheng, Xu-Song; Yang, Ya-Jun; Lu, Zhong-Xian

2014-08-01

Rice black streak dwarf virus (RBSDV) is transmitted by the small brown planthopper (SBPH), Laodelphax striatellus (Fallen). Non-vector rice brown planthopper (BPH), Nilaparvata lugens (Stål), shares the same host rice plants with SBPH in paddy fields. The changes in nutritional composition of rice plants infected by RBSDV and the ecological fitness of BPH feeding on the infected plants were studied under both artificial climate chamber and field conditions. Contents of 16 detected amino acids and soluble sugar in RBSDV infected rice plants were higher than those in the healthy ones. On the diseased plants BPH had significantly higher nymphal survival rates, nymphal duration of the males, weight of the female adults, as well as egg hatchability compared to BPH being fed on healthy plants. However, there was no obvious difference in female nymph duration, longevity and fecundity. Defense enzymes (superoxidase dismutase, SOD and catalase, CAT) and detoxifying enzymes (carboxylesterase, CAE and glutathione S-transferase, GST) in BPH adults fed on diseased plants had markedly higher activities. The results indicate rice plants infected by RBSDV improved the ecological fitness of the brown planthopper, a serious pest but not a transmitter of the RBSDV virus. © 2013 Institute of Zoology, Chinese Academy of Sciences.

Silencing of miR156 confers enhanced resistance to brown planthopper in rice.

PubMed

Ge, Yafei; Han, Junyou; Zhou, Guoxin; Xu, Yunmin; Ding, Yue; Shi, Min; Guo, Changkui; Wu, Gang

2018-06-22

Silencing of miR156 in rice confers enhanced resistance to brown planthopper through reducing JA and JA-Ile biosynthesis. Rice brown planthopper (BPH, Nilaparvata lugens Stål) threatens the sustainability of rice production and global food security. Due to the rapid adaptation of BPH to current germplasms in rice, development of novel types of resistant germplasms becomes increasingly important. Plant ontogenetic defense against pathogen and herbivores offers a broad spectrum and durable resistance, and has been experimentally tested in many plants; however, the underlying molecular mechanism remains unclear. miR156 is the master regulator of ontogeny in plants; modulation of miR156 is, therefore, expected to cause corresponding changes in BPH resistance. To test this hypothesis, we silenced miR156 using a target mimicry method in rice, and analyzed the resistance of miR156-silenced plants (MIM156) to BPH. MIM156 plants exhibited enhanced resistance to BPH based on analyses of honeydew excretion, nymph survival, fecundity of BPH, and the survival ratio of rice plants after BPH infestation. Molecular analysis indicated that the expression of MPK3, MPK6, and WRKY70, three genes involved in BPH resistance and jasmonic acid (JA) signaling, was altered in MIM156 plants. The JA and bioactive jasmonoyl-isoleucine levels and the expression of genes involved in JA biosynthesis were significantly reduced in MIM156 plants. Restoration of JA level by exogenous application increased the number of BPH feeding on MIM156 plants and reduced its resistance to BPH. Our findings suggest that miR156 negatively regulates BPH resistance by increasing JA level in rice; therefore, modulation of miR156-SPLs' pathway may offer a promising way to breed rice varieties with enhanced resistance against BPH and elite agronomically important traits.

Rice choline monooxygenase (OsCMO) protein functions in enhancing glycine betaine biosynthesis in transgenic tobacco but does not accumulate in rice (Oryza sativa L. ssp. japonica).

PubMed

Luo, Di; Niu, Xiangli; Yu, Jinde; Yan, Jun; Gou, Xiaojun; Lu, Bao-Rong; Liu, Yongsheng

2012-09-01

Glycine betaine (GB) is a compatible quaternary amine that enables plants to tolerate abiotic stresses, including salt, drought and cold. In plants, GB is synthesized through two-step of successive oxidations from choline, catalyzed by choline monooxygenase (CMO) and betaine aldehyde dehydrogenase (BADH), respectively. Rice is considered as a typical non-GB accumulating species, although the entire genome sequencing revealed rice contains orthologs of both CMO and BADH. Several studies unraveled that rice has a functional BADH gene, but whether rice CMO gene (OsCMO) is functional or a pseudogene remains to be elucidated. In the present study, we report the functional characterization of rice CMO gene. The OsCMO gene was isolated from rice cv. Nipponbare (Oryza sativa L. ssp. japonica) using RT-PCR. Northern blot demonstrated the transcription of OsCMO is enhanced by salt stress. Transgenic tobacco plants overexpressing OsCMO results in increased GB content and elevated tolerance to salt stress. Immunoblotting analysis demonstrates that a functional OsCMO protein with correct size was present in transgenic tobacco but rarely accumulated in wild-type rice plants. Surprisingly, a large amount of truncated proteins derived from OsCMO was induced in the rice seedlings in response to salt stresses. This suggests that it is the lack of a functional OsCMO protein that presumably results in non-GB accumulation in the tested rice plant. Expression and transgenic studies demonstrate OsCMO is transcriptionally induced in response to salt stress and functions in increasing glycinebetaine accumulation and enhancing tolerance to salt stress. Immunoblotting analysis suggests that no accumulation of glycinebetaine in the Japonica rice plant presumably results from lack of a functional OsCMO protein.

Silicon Supplementation Alters the Composition of Herbivore Induced Plant Volatiles and Enhances Attraction of Parasitoids to Infested Rice Plants.

PubMed

Liu, Jian; Zhu, Jiwei; Zhang, Pengjun; Han, Liwei; Reynolds, Olivia L; Zeng, Rensen; Wu, Jinhong; Shao, Yue; You, Minsheng; Gurr, Geoff M

2017-01-01

Silicon (Si) is important in plant defenses that operate in a direct manner against herbivores, and work in rice ( Oryza sativa ) has established that this is mediated by the jasmonate signaling pathway. Plant defenses also operate indirectly, by the production of herbivore induced plant volatiles (HIPVs) that attract predators and parasitoids of herbivores. These indirect defenses too are mediated by the jasmonate pathway but no earlier work has demonstrated an effect of Si on HIPVs. In this study, we tested the effect of Si supplementation versus Si deprivation to rice plants on subsequent HIPV production following feeding by the important pest, rice leaffolder ( Cnaphalocrocis medinalis ). Gas chromatography-mass spectrometry analyses showed lower production of α-bergamotene, β-sesquiohellandrene, hexanal 2-ethyl, and cedrol from +Si herbivore-infested plants compared with -Si infested plants. These changes in plant chemistry were ecologically significant in altering the extent to which parasitoids were attracted to infested plants. Adult females of Trathala flavo-orbitalis and Microplitis mediator both exhibited greater attraction to the HIPV blend of +Si plants infested with their respective insect hosts compared to -Si infested plants. In equivalent studies using RNAi rice plants in which jasmonate perception was silenced there was no equivalent change to the HIPV blend associated with Si treatment; indicating that the effects of Si on HIPVs are modulated by the jasmonate pathway. Further, this work demonstrates that silicon alters the HIPV blend of herbivore-infested rice plants. The significance of this finding is that there are no earlier-published studies of this phenomenon in rice or any other plant species. Si treatment to crops offers scope for enhancing induced, indirect defenses and associated biological control of pests because parasitoids are more strongly attracted by the HIPVs produced by +Si plants.

Spatiotemporal patterns of paddy rice croplands in China and India from 2000 to 2015.

PubMed

Zhang, Geli; Xiao, Xiangming; Biradar, Chandrashekhar M; Dong, Jinwei; Qin, Yuanwei; Menarguez, Michael A; Zhou, Yuting; Zhang, Yao; Jin, Cui; Wang, Jie; Doughty, Russell B; Ding, Mingjun; Moore, Berrien

2017-02-01

Due to rapid population growth and urbanization, paddy rice agriculture is experiencing substantial changes in the spatiotemporal pattern of planting areas in the two most populous countries-China and India-where food security is always the primary concern. However, there is no spatially explicit and continuous rice-planting information in either country. This knowledge gap clearly hinders our ability to understand the effects of spatial paddy rice area dynamics on the environment, such as food and water security, climate change, and zoonotic infectious disease transmission. To resolve this problem, we first generated annual maps of paddy rice planting areas for both countries from 2000 to 2015, which are derived from time series Moderate Resolution Imaging Spectroradiometer (MODIS) data and the phenology- and pixel-based rice mapping platform (RICE-MODIS), and analyzed the spatiotemporal pattern of paddy rice dynamics in the two countries. We found that China experienced a general decrease in paddy rice planting area with a rate of 0.72 million (m) ha/yr from 2000 to 2015, while a significant increase at a rate of 0.27mha/yr for the same time period happened in India. The spatial pattern of paddy rice agriculture in China shifted northeastward significantly, due to simultaneous expansions in paddy rice planting areas in northeastern China and contractions in southern China. India showed an expansion of paddy rice areas across the entire country, particularly in the northwestern region of the Indo-Gangetic Plain located in north India and the central and south plateau of India. In general, there has been a northwesterly shift in the spatial pattern of paddy rice agriculture in India. These changes in the spatiotemporal patterns of paddy rice planting area have raised new concerns on how the shift may affect national food security and environmental issues relevant to water, climate, and biodiversity. Copyright © 2016 Elsevier B.V. All rights reserved.

Dietary mineral supplies in Africa

PubMed Central

Joy, Edward J M; Ander, E Louise; Young, Scott D; Black, Colin R; Watts, Michael J; Chilimba, Allan D C; Chilima, Benson; Siyame, Edwin W P; Kalimbira, Alexander A; Hurst, Rachel; Fairweather-Tait, Susan J; Stein, Alexander J; Gibson, Rosalind S; White, Philip J; Broadley, Martin R

2014-01-01

Dietary micronutrient deficiencies (MNDs) are widespread, yet their prevalence can be difficult to assess. Here, we estimate MND risks due to inadequate intakes for seven minerals in Africa using food supply and composition data, and consider the potential of food-based and agricultural interventions. Food Balance Sheets (FBSs) for 46 countries were integrated with food composition data to estimate per capita supply of calcium (Ca), copper (Cu), iron (Fe), iodine (I), magnesium (Mg), selenium (Se) and zinc (Zn), and also phytate. Deficiency risks were quantified using an estimated average requirement (EAR) ‘cut-point’ approach. Deficiency risks are highest for Ca (54% of the population), followed by Zn (40%), Se (28%) and I (19%, after accounting for iodized salt consumption). The risk of Cu (1%) and Mg (<1%) deficiency are low. Deficiency risks are generally lower in the north and west of Africa. Multiple MND risks are high in many countries. The population-weighted mean phytate supply is 2770 mg capita−1 day−1. Deficiency risks for Fe are lower than expected (5%). However, ‘cut-point’ approaches for Fe are sensitive to assumptions regarding requirements; e.g. estimates of Fe deficiency risks are 43% under very low bioavailability scenarios consistent with high-phytate, low-animal protein diets. Fertilization and breeding strategies could greatly reduce certain MNDs. For example, meeting harvestplus breeding targets for Zn would reduce dietary Zn deficiency risk by 90% based on supply data. Dietary diversification or direct fortification is likely to be needed to address Ca deficiency risks. PMID:24524331

Enhanced conversion of plant biomass into glucose using transgenic rice-produced endoglucanase for cellulosic ethanol.

PubMed

Oraby, Hesham; Venkatesh, Balan; Dale, Bruce; Ahmad, Rashid; Ransom, Callista; Oehmke, James; Sticklen, Mariam

2007-12-01

The catalytic domain of Acidothermus cellulolyticus thermostable endoglucanase gene (encoding for endo-1,4-beta-glucanase enzyme or E1) was constitutively expressed in rice. Molecular analyses of T1 plants confirmed presence and expression of the transgene. The amount of E1 enzyme accounted for up to 4.9% of the plant total soluble proteins, and its accumulation had no apparent deleterious effects on plant growth and development. Approximately 22 and 30% of the cellulose of the Ammonia Fiber Explosion (AFEX)-pretreated rice and maize biomass respectively was converted into glucose using rice E1 heterologous enzyme. As rice is the major food crop of the world with minimal use for its straw, our results suggest a successful strategy for producing biologically active hydrolysis enzymes in rice to help generate alcohol fuel, by substituting the wasteful and polluting practice of rice straw burning with an environmentally friendly technology.

Analysis of Growth and Molecular Responses to Ethylene in Etiolated Rice Seedlings.

PubMed

Ma, Biao; Zhang, Jin-Song

2017-01-01

Ethylene plays a key role in various submergence responses of rice plants, but the mechanism of ethylene action remains largely unclear in rice. Regarding the differences between rice and Arabidopsis in ethylene-regulated processes, rice plants may possess divergent mechanisms in ethylene signaling in addition to the conserved aspects. Forward genetic analysis is essential to fully understand the ethylene signaling mechanism in rice. Here, we describe a method for screening ethylene-response mutants and evaluating ethylene responsiveness in etiolated rice seedlings.

Delivering golden rice to developing countries.

PubMed

Mayer, Jorge E

2007-01-01

Micronutrient deficiencies create a vicious circle of malnutrition, poverty, and economic dependency that we must strive to break. Golden Rice offers a sustainable solution to reduce the prevalence of vitamin A deficiency-related diseases and mortality, a problem that affects the health of millions of children in all developing countries. The technology is based on the reconstitution of the carotenoid biosynthetic pathway by addition of 2 transgenes. The outcome of this high-tech approach will be provided to end users as nutrient-dense rice varieties that are agronomically identical to their own, locally adapted varieties. This intervention has the potential to reach remote rural populations without access to fortification and supplementation programs. As part of our delivery strategy, we are partnering with government and nongovernment, national and international agricultural institutions to navigate through cumbersome and expensive regulatory regimes that affect the release of genetically modified crops, and to create local demand for the biofortified rice varieties.

Effect of polluted water on soil and plant contamination by heavy metals in El-Mahla El-Kobra, Egypt

NASA Astrophysics Data System (ADS)

Kasem Mahmoud, Esawy; Ghoneim, Adel Mohamed

2016-04-01

The discharge of untreated waste water in Zefta drain and drain no. 5 is becoming a problem for many farmers in the El-Mahla El-Kobra area, Egypt. The discharged water contains high levels of contaminants considered hazardous to the ecosystem. Some plants, soil, water, and sediment samples were collected from the El-Mahla El-Kobra area to evaluate the contamination by heavy metals. The results showed that the heavy metals, pH, sodium adsorption ratio (SAR), biochemical oxygen demand (BOD), and chemical oxygen demand (COD) in the water of Zefta drain and drain no. 5 exceeded permissible limits for irrigation. In rice and maize shoots grown in soils irrigated by contaminated water from Zefta drain and drain no. 5, the bioaccumulation factors for Cd, Pb, Zn, Cu, and Mn were higher than 1.0. The heavy metals content of irrigated soils from Zefta drain and drain no. 5 exceeded the upper limit of background heavy metals. In this study, the mean contaminant factor values of the drain no. 5 sediments revealed that Zn, Mn, Cu, Cd, Pb, and Ni > 6, indicating very high contamination. The bioaccumulation coefficient values of Cynodon dactylon, Phragmites australis, and Typha domingensis aquatic plants growing in Zefta drain are high. These species can be considered as hyperaccumulators for the decontamination of contaminated water.

Changes of paddy rice planting areas in Northeastern Asia from 1986 to 2014 based on Landsat data

NASA Astrophysics Data System (ADS)

Dong, J.; Xiao, X.; Kou, W.; Qin, Y.; Wang, J.; Zhang, G.; Jin, C.; Zhou, Y.; Menarguez, M. A.; Moore, B., III

2014-12-01

Paddy rice is an important cereal crop and main grain source for more than half of the global human population. However, knowledge about its area and spatial pattern is still limited due to large changes in agriculture in different regions; for example, higher latitude areas underwent increase (e.g., northeastern China) and decrease (e.g., South Korea) of paddy rice planting areas due to climatic warming, urbanization and other drivers. It is necessary to track paddy rice planting area changes in these regions in the past decades. We developed a pixel- and phenology-based image analysis system, Landsat-RICE, to map the paddy rice by using Landsat imagery. The algorithm was based on the unique physical and spectral characteristics of paddy rice fields during the flooding and transplanting phases. First, Landsat images are preprocessed and time series vegetation indices (NDVI, EVI, and LSWI) are generated. Second, MODIS Land Surface Temperature (LST) data were used to define thermal plant growing season (0 oC, 5 oC and 10 oC), which provides a guide for selection of Landsat images within the period of flooding and transplanting. Third, several non-cropland land cover maps (e.g., permanent water bodies, built-up and barren lands, sparsely vegetated lands, and evergreen vegetation) are produced through analysis of Landsat-based vegetation indices within the plant growing season and combined as a mask. Fourthly, vegetation index data within the time window of flooded and rice transplanting were analyzed to identify flood/transplanting signals. Finally, the maps of paddy rice planting areas were generated through overlying the results from Step 3 and 4. Paddy rice planting area changes were investigated in some hotspots of Northeastern Asia from 1986 to 2014 at 30-m spatial resolution and 5-year interval. This study has demonstrated that our newly developed Landsat-Rice system is robust and effective for tracking paddy rice changes in cold temperate and temperate zones.

The heavy metal paradox in arbuscular mycorrhizas: from mechanisms to biotechnological applications.

PubMed

Ferrol, Nuria; Tamayo, Elisabeth; Vargas, Paola

2016-12-01

Arbuscular mycorrhizal symbioses that involve most plants and Glomeromycota fungi are integral and functional parts of plant roots. In these associations, the fungi not only colonize the root cortex but also maintain an extensive network of hyphae that extend out of the root into the surrounding environment. These external hyphae contribute to plant uptake of low mobility nutrients, such as P, Zn, and Cu. Besides improving plant mineral nutrition, arbuscular mycorrhizal fungi (AMF) can alleviate heavy metal (HM) toxicity to their host plants. HMs, such as Cu, Zn, Fe, and Mn, play essential roles in many biological processes but are toxic when present in excess. This makes their transport and homeostatic control of particular importance to all living organisms. AMF play an important role in modulating plant HM acquisition in a wide range of soil metal concentrations and have been considered to be a key element in the improvement of micronutrient concentrations in crops and in the phytoremediation of polluted soils. In the present review, we provide an overview of the contribution of AMF to plant HM acquisition and performance under deficient and toxic HM conditions, and summarize current knowledge of metal homeostasis mechanisms in arbuscular mycorrhizas. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

CONSTANS-like 9 (COL9) delays the flowering time in Oryza sativa by repressing the Ehd1 pathway.

PubMed

Liu, Hao; Gu, Fengwei; Dong, Shuangyu; Liu, Wei; Wang, Hui; Chen, Zhiqiang; Wang, Jiafeng

2016-10-14

Flowering or heading is one of most important agronomic traits in rice. It has been characterized that CONSTANS (CO) and CONSTANS-like (COL) proteins are critical flowering regulators in response to photoperiodic stress in plants. We have previously identified that the COL family member OsCOL9 can positively enhance the rice blast resistance. In the present study, we aimed to explore the functional role of OsCOL9 in modulating the photoperiodic flowering. Our data showed that overexpression of OsCOL9 delayed the flowering time under both short-day (SD) and long-day (LD) conditions, leading to suppressed expressions of EHd1, RFT and Hd3a at the mRNA Level. OsCOL9 expression exhibited two types of circadian patterns under different daylight conditions, and it could delay the heading date by suppressing the Ehd1 photoperiodic flowering pathway. In contrast, the expressions of previously reported flowering regulators were not significantly changed in OsCOL9 transgenic plants, indicating that OsCOL9 functioned independently of other flowering pathways. In addition, OsCOL9 served as a potential yield gene, and its deficiency reduced the grain number of main panicle in plants. Furthermore, yeast two-hybrid assay indicated that OsCOL9 physically interacted with Receptor for Activated C-kinase 1 (OsRACK1). Rhythmic pattern analysis suggested that OsRACK1 responded to the change of daylight, which was regulated by the circadian clock. Taken together, our results revealed that OsCOL9 could delay the flowering time in rice by repressing the Ehd1 pathway. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Root microbiota shift in rice correlates with resident time in the field and developmental stage.

PubMed

Zhang, Jingying; Zhang, Na; Liu, Yong-Xin; Zhang, Xiaoning; Hu, Bin; Qin, Yuan; Xu, Haoran; Wang, Hui; Guo, Xiaoxuan; Qian, Jingmei; Wang, Wei; Zhang, Pengfan; Jin, Tao; Chu, Chengcai; Bai, Yang

2018-06-01

Land plants in natural soil form intimate relationships with the diverse root bacterial microbiota. A growing body of evidence shows that these microbes are important for plant growth and health. Root microbiota composition has been widely studied in several model plants and crops; however, little is known about how root microbiota vary throughout the plant's life cycle under field conditions. We performed longitudinal dense sampling in field trials to track the time-series shift of the root microbiota from two representative rice cultivars in two separate locations in China. We found that the rice root microbiota varied dramatically during the vegetative stages and stabilized from the beginning of the reproductive stage, after which the root microbiota underwent relatively minor changes until rice ripening. Notably, both rice genotype and geographical location influenced the patterns of root microbiota shift that occurred during plant growth. The relative abundance of Deltaproteobacteria in roots significantly increased overtime throughout the entire life cycle of rice, while that of Betaproteobacteria, Firmicutes, and Gammaproteobacteria decreased. By a machine learning approach, we identified biomarker taxa and established a model to correlate root microbiota with rice resident time in the field (e.g., Nitrospira accumulated from 5 weeks/tillering in field-grown rice). Our work provides insights into the process of rice root microbiota establishment.

Method for estimating rice plant height without ground surface detection using laser scanner measurement

NASA Astrophysics Data System (ADS)

Thi Phan, Anh Thu; Takahashi, Kazuyoshi; Rikimaru, Atsushi; Higuchi, Yasuhiro

2016-10-01

A method for estimating the height of rice plants, using three-dimensional laser range data from point clouds, is proposed and assessed. Rice plant height (H) is estimated using a reference position at the top of the rice plant, avoiding the need to determine the ground position. Field experiments were performed with a SICK LMS 200 laser scanner in 2013 and 2014 on a test field with five different planting geometries. Percentile analysis identified the closest percentile to the top of the rice plant (pt=1), with vertical distances at the first percentile unaffected by planting geometry. The plant bottom position was identified using three different percentile ranks (pb=95, pb =80, and pb =70). Relative vertical distances (rD) were computed from the difference between the top and bottom positions of the rice plant. These correlated well with measured H, with slopes greater than 1.0. A greater number of stems in 2014 led to steeper slopes. Estimated H was more accurate when plant bottom positions were closer to the ground surface, and the best results were obtained with pb=95 (r2>0.87 RMSE≈4 cm). Overall, H was typically 16.0 cm greater than rD with pb=95.

Examination of the semi-automatic calculation technique of vegetation cover rate by digital camera images.

NASA Astrophysics Data System (ADS)

Takemine, S.; Rikimaru, A.; Takahashi, K.

The rice is one of the staple foods in the world High quality rice production requires periodically collecting rice growth data to control the growth of rice The height of plant the number of stem the color of leaf is well known parameters to indicate rice growth Rice growth diagnosis method based on these parameters is used operationally in Japan although collecting these parameters by field survey needs a lot of labor and time Recently a laborsaving method for rice growth diagnosis is proposed which is based on vegetation cover rate of rice Vegetation cover rate of rice is calculated based on discriminating rice plant areas in a digital camera image which is photographed in nadir direction Discrimination of rice plant areas in the image was done by the automatic binarization processing However in the case of vegetation cover rate calculation method depending on the automatic binarization process there is a possibility to decrease vegetation cover rate against growth of rice In this paper a calculation method of vegetation cover rate was proposed which based on the automatic binarization process and referred to the growth hysteresis information For several images obtained by field survey during rice growing season vegetation cover rate was calculated by the conventional automatic binarization processing and the proposed method respectively And vegetation cover rate of both methods was compared with reference value obtained by visual interpretation As a result of comparison the accuracy of discriminating rice plant areas was increased by the proposed

Identification of Rice Genes Associated With Enhanced Cold Tolerance by Comparative Transcriptome Analysis With Two Transgenic Rice Plants Overexpressing DaCBF4 or DaCBF7, Isolated From Antarctic Flowering Plant Deschampsia antarctica

PubMed Central

Byun, Mi Young; Cui, Li Hua; Lee, Jungeun; Park, Hyun; Lee, Andosung; Kim, Woo Taek; Lee, Hyoungseok

2018-01-01

Few plant species can survive in Antarctica, the harshest environment for living organisms. Deschampsia antarctica is the only natural grass species to have adapted to and colonized the maritime Antarctic. To investigate the molecular mechanism of the Antarctic adaptation of this plant, we identified and characterized D. antarctica C-repeat binding factor 4 (DaCBF4), which belongs to monocot CBF group IV. The transcript level of DaCBF4 in D. antarctica was markedly increased by cold and dehydration stress. To assess the roles of DaCBF4 in plants, we generated a DaCBF4-overexpressing transgenic rice plant (Ubi:DaCBF4) and analyzed its abiotic stress response phenotype. Ubi:DaCBF4 displayed enhanced tolerance to cold stress without growth retardation under any condition compared to wild-type plants. Because the cold-specific phenotype of Ubi:DaCBF4 was similar to that of Ubi:DaCBF7 (Byun et al., 2015), we screened for the genes responsible for the improved cold tolerance in rice by selecting differentially regulated genes in both transgenic rice lines. By comparative transcriptome analysis using RNA-seq, we identified 9 and 15 genes under normal and cold-stress conditions, respectively, as putative downstream targets of the two D. antarctica CBFs. Overall, our results suggest that Antarctic hairgrass DaCBF4 mediates the cold-stress response of transgenic rice plants by adjusting the expression levels of a set of stress-responsive genes in transgenic rice plants. Moreover, selected downstream target genes will be useful for genetic engineering to enhance the cold tolerance of cereal plants, including rice. PMID:29774046

Identification of Rice Genes Associated With Enhanced Cold Tolerance by Comparative Transcriptome Analysis With Two Transgenic Rice Plants Overexpressing DaCBF4 or DaCBF7, Isolated From Antarctic Flowering Plant Deschampsia antarctica.

PubMed

Byun, Mi Young; Cui, Li Hua; Lee, Jungeun; Park, Hyun; Lee, Andosung; Kim, Woo Taek; Lee, Hyoungseok

2018-01-01

Few plant species can survive in Antarctica, the harshest environment for living organisms. Deschampsia antarctica is the only natural grass species to have adapted to and colonized the maritime Antarctic. To investigate the molecular mechanism of the Antarctic adaptation of this plant, we identified and characterized D. antarctica C-repeat binding factor 4 ( DaCBF4 ), which belongs to monocot CBF group IV. The transcript level of DaCBF4 in D. antarctica was markedly increased by cold and dehydration stress. To assess the roles of DaCBF4 in plants, we generated a DaCBF4 -overexpressing transgenic rice plant ( Ubi:DaCBF4 ) and analyzed its abiotic stress response phenotype. Ubi:DaCBF4 displayed enhanced tolerance to cold stress without growth retardation under any condition compared to wild-type plants. Because the cold-specific phenotype of Ubi:DaCBF4 was similar to that of Ubi:DaCBF7 (Byun et al., 2015), we screened for the genes responsible for the improved cold tolerance in rice by selecting differentially regulated genes in both transgenic rice lines. By comparative transcriptome analysis using RNA-seq, we identified 9 and 15 genes under normal and cold-stress conditions, respectively, as putative downstream targets of the two D. antarctica CBFs. Overall, our results suggest that Antarctic hairgrass DaCBF4 mediates the cold-stress response of transgenic rice plants by adjusting the expression levels of a set of stress-responsive genes in transgenic rice plants. Moreover, selected downstream target genes will be useful for genetic engineering to enhance the cold tolerance of cereal plants, including rice.

The rice dwarf virus P2 protein interacts with ent-kaurene oxidases in vivo, leading to reduced biosynthesis of gibberellins and rice dwarf symptoms.

PubMed

Zhu, Shifeng; Gao, Feng; Cao, Xuesong; Chen, Mao; Ye, Gongyin; Wei, Chunhong; Li, Yi

2005-12-01

The mechanisms of viral diseases are a major focus of biology. Despite intensive investigations, how a plant virus interacts with host factors to cause diseases remains poorly understood. The Rice dwarf virus (RDV), a member of the genus Phytoreovirus, causes dwarfed growth phenotypes in infected rice (Oryza sativa) plants. The outer capsid protein P2 is essential during RDV infection of insects and thus influences transmission of RDV by the insect vector. However, its role during RDV infection within the rice host is unknown. By yeast two-hybrid and coimmunoprecipitation assays, we report that P2 of RDV interacts with ent-kaurene oxidases, which play a key role in the biosynthesis of plant growth hormones gibberellins, in infected plants. Furthermore, the expression of ent-kaurene oxidases was reduced in the infected plants. The level of endogenous GA1 (a major active gibberellin in rice vegetative tissues) in the RDV-infected plants was lower than that in healthy plants. Exogenous application of GA3 to RDV-infected rice plants restored the normal growth phenotypes. These results provide evidence that the P2 protein of RDV interferes with the function of a cellular factor, through direct physical interactions, that is important for the biosynthesis of a growth hormone leading to symptom expression. In addition, the interaction between P2 and rice ent-kaurene oxidase-like proteins may decrease phytoalexin biosynthesis and make plants more competent for virus replication. Moreover, P2 may provide a novel tool to investigate the regulation of GA metabolism for plant growth and development.

The Rice Dwarf Virus P2 Protein Interacts with ent-Kaurene Oxidases in Vivo, Leading to Reduced Biosynthesis of Gibberellins and Rice Dwarf Symptoms1

PubMed Central

Zhu, Shifeng; Gao, Feng; Cao, Xuesong; Chen, Mao; Ye, Gongyin; Wei, Chunhong; Li, Yi

2005-01-01

The mechanisms of viral diseases are a major focus of biology. Despite intensive investigations, how a plant virus interacts with host factors to cause diseases remains poorly understood. The Rice dwarf virus (RDV), a member of the genus Phytoreovirus, causes dwarfed growth phenotypes in infected rice (Oryza sativa) plants. The outer capsid protein P2 is essential during RDV infection of insects and thus influences transmission of RDV by the insect vector. However, its role during RDV infection within the rice host is unknown. By yeast two-hybrid and coimmunoprecipitation assays, we report that P2 of RDV interacts with ent-kaurene oxidases, which play a key role in the biosynthesis of plant growth hormones gibberellins, in infected plants. Furthermore, the expression of ent-kaurene oxidases was reduced in the infected plants. The level of endogenous GA1 (a major active gibberellin in rice vegetative tissues) in the RDV-infected plants was lower than that in healthy plants. Exogenous application of GA3 to RDV-infected rice plants restored the normal growth phenotypes. These results provide evidence that the P2 protein of RDV interferes with the function of a cellular factor, through direct physical interactions, that is important for the biosynthesis of a growth hormone leading to symptom expression. In addition, the interaction between P2 and rice ent-kaurene oxidase-like proteins may decrease phytoalexin biosynthesis and make plants more competent for virus replication. Moreover, P2 may provide a novel tool to investigate the regulation of GA metabolism for plant growth and development. PMID:16299167

A systems-wide comparison of red rice (Oryza longistaminata) tissues identifies rhizome specific genes and proteins that are targets for cultivated rice improvement

PubMed Central

2014-01-01

Background The rhizome, the original stem of land plants, enables species to invade new territory and is a critical component of perenniality, especially in grasses. Red rice (Oryza longistaminata) is a perennial wild rice species with many valuable traits that could be used to improve cultivated rice cultivars, including rhizomatousness, disease resistance and drought tolerance. Despite these features, little is known about the molecular mechanisms that contribute to rhizome growth, development and function in this plant. Results We used an integrated approach to compare the transcriptome, proteome and metabolome of the rhizome to other tissues of red rice. 116 Gb of transcriptome sequence was obtained from various tissues and used to identify rhizome-specific and preferentially expressed genes, including transcription factors and hormone metabolism and stress response-related genes. Proteomics and metabolomics approaches identified 41 proteins and more than 100 primary metabolites and plant hormones with rhizome preferential accumulation. Of particular interest was the identification of a large number of gene transcripts from Magnaportha oryzae, the fungus that causes rice blast disease in cultivated rice, even though the red rice plants showed no sign of disease. Conclusions A significant set of genes, proteins and metabolites appear to be specifically or preferentially expressed in the rhizome of O. longistaminata. The presence of M. oryzae gene transcripts at a high level in apparently healthy plants suggests that red rice is resistant to this pathogen, and may be able to provide genes to cultivated rice that will enable resistance to rice blast disease. PMID:24521476

Agricultural biotechnology. Monsanto donates its share of golden rice.

PubMed

Normile, D

2000-08-11

Monsanto Co. has agreed to provide royalty-free licenses to speed up work on a genetically modified rice that could alleviate vitamin A deficiency around the world. Researchers welcomed last week's announcement, but warn that a thicket of intellectual property claims surrounds the technology and that significant legal hurdles remain before the rice can become widely available to farmers in developing countries.

Separation of Allelopathy from Resource Competition Using Rice/Barnyardgrass Mixed-Cultures

PubMed Central

Fang, Chang Xun; Lin, Zhi Hua; Yu, Zheng Ming; Lin, Wen Xiong

2012-01-01

Plant-plant interference is the combined effect of allelopathy, resource competition, and many other factors. Separating allelopathy from resource competition is almost impossible in natural systems but it is important to evaluate the relative contribution of each of the two mechanisms on plant interference. Research on allelopathy in natural and cultivated plant communities has been hindered in the absence of a reliable method that can separate allelopathic effect from resource competition. In this paper, the interactions between allelopathic rice accession PI312777, non-allelopathic rice accession Lemont and barnyardgrass were explored respectively by using a target (rice)-neighbor (barnyardgrass) mixed-culture in hydroponic system. The relative competitive intensity (RCI), the relative neighbor effect (RNE) and the competitive ratio (CR) were used to quantify the intensity of competition between each of the two different potentially allelopathic rice accessions and barnyardgrass. Use of hydroponic culture system enabled us to exclude any uncontrolled factors that might operate in the soil and we were able to separate allelopathy from resource competition between each rice accession and barnyardgrass. The RCI and RNE values showed that the plant-plant interaction was positive (facilitation) for PI312777 but that was negative (competition) for Lemont and barnyardgrass in rice/barnyardgrass mixed-cultures. The CR values showed that one PI312777 plant was more competitive than 2 barnyardgrass plants. The allelopathic effects of PI312777 were much more intense than the resource competition in rice/barnyardgrass mixed cultures. The reverse was true for Lemont. These results demonstrate that the allelopathic effect of PI312777 was predominant in rice/barnyardgrass mixed-cultures. The most significant result of our study is the discovery of an experimental design, target-neighbor mixed-culture in combination with competition indices, can successfully separate allelopathic effects from competition. PMID:22590655

In-Situ Quantification of Microbial Processes Controlling Methane Emissions From Rice Plants

NASA Astrophysics Data System (ADS)

Schroth, M. H.; Cho, R.; Zeyer, J. A.

2011-12-01

Methane is an important greenhouse gas contributing to global warming. Among other sources, rice (paddy) soils represent a major nonpoint source of biogenic methane. In flooded paddy soils methane is produced under anaerobic conditions. Conversely, methanotrophic microorganisms oxidize methane to carbon dioxide in the root zone of rice plants, thus reducing overall methane emissions to the atmosphere. We present a novel combination of methods to quantify methanogenesis and methane oxidation in paddy soils and to link methane turnover to net emissions of rice plants. To quantify methane turnover in the presence of high methane background concentrations, small-scale push-pull tests (PPTs) were conducted in paddy soils using stable isotope-labeled substrates. Deuterated acetate and 13-C bicarbonate were employed to discern and quantify acetoclastic and hydrogenotrophic methanogenesis, while 13-C methane was employed to quantify methane oxidation. During 2.5 hr-long PPTs, 140 mL of a test solution containing labeled substrates and nonreactive tracers (Ar, Br-) was injected into paddy soils of potted rice plants. After a short rest period, 480 mL of test solution/pore water mixture was extracted from the same location. Methane turnover was then computed from extraction-phase breakthrough curves of substrates and/or products, and nonreactive tracers. To link methane turnover to net emissions, methane emissions from paddy soils and rice plants were individually determined immediately preceding PPTs using static flux chambers. We will present results of a series of experiments conducted in four different potted rice plants. Preliminary results indicate substantial variability in methane turnover and net emission between different rice plants. The employed combination of methods appears to provide a robust means to quantitatively link methane turnover in paddy soils to net emissions from rice plants.

Flavonoids inhibit both rice and sheep serotonin N-acetyltransferases and reduce melatonin levels in plants.

PubMed

Lee, Kyungjin; Hwang, Ok Jin; Reiter, Russel J; Back, Kyoungwhan

2018-05-31

The plant melatonin biosynthetic pathway has been well characterized, but inhibitors of melatonin synthesis have not been well studied. Here, we found that flavonoids potently inhibited plant melatonin synthesis. For example, flavonoids including morin and myricetin significantly inhibited purified, recombinant sheep serotonin N-acetyltransferase (SNAT). Flavonoids also dose-dependently and potently inhibited purified rice SNAT1 and SNAT2. Thus, myricetin (100 μmol/L) reduced rice SNAT1 and SNAT2 activity 7- and 10-fold, respectively, and also strongly inhibited the N-acetylserotonin methyltransferase activity of purified, recombinant rice caffeic acid O-methyltransferase. To explore the in vivo effects, rice leaves were treated with flavonoids and then cadmium. Flavonoid-treated leaves had lower melatonin levels than the untreated control. To explore the direct roles of flavonoids in melatonin biosynthesis, we first functionally characterized a putative rice flavonol synthase (FLS) in vitro and generated flavonoid-rich transgenic rice plants that overexpressed FLS. Such plants produced more flavonoids but less melatonin than the wild-type, which suggests that flavonoids indeed inhibit plant melatonin biosynthesis. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Electrophysiological responses of the rice leaffolder, cnaphalocrocis medinalis (lepidoptera: pyralidae), to rice plant volatiles

USDA-ARS?s Scientific Manuscript database

The electrophysiological activities of 38 synthetic volatiles that were known to be released from the rice plants (Poaceae: Oryza spp.) were studied using electroantennogram (EAG) recording technique on male and female antennae of the rice leaffolder, Cnaphalocrocis medinalis (Guenée) (Lepidoptera: ...

Zinc, lead, and cadmium levels in serum and milk of lactating women in Ibadan, Nigeria.

PubMed

Edem, Victory Fabian; Akintunde, Kikelomo; Adelaja, Yewande Adeola; Nwozo, Sarah O; Charles-Davies, Mabel

2017-01-01

Zinc (Zn) is known to interact with lead (Pb) and cadmium (Cd) reversing their toxicity and reducing their concentrations. However, lactating women are at high risk of developing Zn deficiency, which may result in Pb and Cd intoxication or increased exposure of breast-fed infants to Pb and Cd from breast milk. The aim of this study was to determine Zn, Pb, and Cd concentrations and examine their relationship in serum and breast milk of lactating women in Ibadan, Nigeria. Ninety-two lactating women were recruited into this study. Anthropometric measurements were assessed by standard methods while serum and breast milk concentrations of Zn, Pb, and Cd were assessed by atomic absorption spectrophotometry. Data analyzed statistically by Student's t test, Pearson's correlation coefficient, and a multiple regression model were significant at p < 0.05. Zn deficiency was observed in 12 (17.1%) of lactating women. Breast milk levels of Zn, Pb, and Cd were significantly higher than their levels in serum, whereas the ratios Zn:Pb and Zn:Cd in milk were significantly less than serum ratios. Significant negative correlation was observed between milk Pb and serum Zn:Pb while milk Cd correlated positively with milk Zn. Significant positive correlations were observed between serum Zn and serum Zn:Pb, serum Zn and serum Zn:Cd, as well as serum Zn:Cd and serum Zn:Pb. Serum Cd and serum Zn were significantly negatively related. Significant negative correlations between serum Pb and serum Zn:Pb as well as milk Zn:Pb. Serum Cd and serum Zn:Pb as well as serum Zn:Cd correlated negatively. Milk Cd and Zn/Cd positively related with milk Pb while milk Zn was a negatively related with milk Pb in a multiple regression model ( R 2 = 0.333; p = 0.023). Breast milk may be contaminated by toxic metals. However, Zn supplementation in deficient mothers may protect maternal and infant health.

Constitutive expression of a plant ferredoxin-like protein (pflp) enhances capacity of photosynthetic carbon assimilation in rice (Oryza sativa).

PubMed

Chang, Hsiang; Huang, Hsiang-En; Cheng, Chin-Fu; Ho, Mei-Hsuan; Ger, Mang-Jye

2017-04-01

The plant ferredoxin-like protein (PFLP) gene, cloned from sweet peppers predicted as an electron carrier in photosynthesis, shows high homology to the Fd-I sequence of Arabidopsis thaliana, Lycopersicon esculentum, Oryza sativa and Spinacia oleracea. Most of pflp related studies focused on anti-pathogenic effects, while less understanding for the effects in photosynthesis with physiological aspects, such as photosynthesis rate, and levels of carbohydrate metabolites. This project focuses on the effects of pflp overexpression on photosynthesis by physiological evaluations of carbon assimilation with significant higher levels of carbohydrates with higher photosynthesis efficiency. In this report, two independent transgenic lines of rice plants (designated as pflp-1 and pflp-2) were generated from non-transgenic TNG67 rice plant (WT). Both transgenic pflp rice plants exhibited enhanced photosynthesis efficiency, and gas exchange rates of photosynthesis were 1.3- and 1.2-fold higher for pflp-1 and pflp-2 than WT respectively. Significantly higher electron transport rates of pflp rice plants were observed. Moreover, photosynthetic products, such as fructose, glucose, sucrose and starch contents of pflp transgenic lines were increased accordingly. Molecular evidences of carbohydrate metabolism related genes activities (osHXK5, osHXK6, osAGPL3, osAGPS2α, osSPS, ospFBPase, oscFBPase, and osSBPase) in transgenic lines were higher than those of WT. For performance of crop production, 1000-grain weight for pflp-1 and pflp-2 rice plants were 52.9 and 41.1 g that were both significantly higher than 31.6 g for WT, and panicles weights were 1.4- and 1.2-fold higher than WT. Panicle number, tiller number per plants for pflp rice plants were all significantly higher compared with those of WT where there was no significant difference observed between two pflp rice plants. Taken altogether; this study demonstrated that constitutive pflp expression can improve rice production by enhancing the capacity of photosynthetic carbon assimilation.

Adaptational changes in the lipids and fatty acid profile of the cell and thylakoid membrane of rice plants exposed to sunlight.

PubMed

Vaz, Janet F; Sharma, Prabhat Kumar

2010-07-01

Adaptational changes occurring in the lipids and fatty acids of the cell and the thylakoid membrane in response to high light treatment, was studied in 30 days old rice (Oryza sativa L. cv. Jyothi) plants grown under low (150-200 μmol m(-2) s(-1)) or moderate (600-800 μmol m(-2) s(-1)) light conditions. Results were compared with rice plants grown in high (1200-2200 μmol m(-2) s(-1)) light conditions. Exposure of rice plants and isolated chloroplast to high light, resulted in an increase in the amount of malonaldehyde, indicating oxidation of membrane lipids. Qualitative and quantitative changes in the phosphoglycolipids and quantitative changes in neutral lipids were observed in rice plants grown under the different growth conditions. A few of the phosphoglycolipids and neutral lipids were present exclusively in plants grown at low or moderate or high light, indicating requirement of different type of lipid composition of rice plants in response to their different growth irradiances. However, no significant quantitative changes were observed in the different saturated and unsaturated fatty acid groups of total lipids in low, moderate and high light grown rice plants, as a result of exposure to high light. No qualitative changes in the fatty acid composition due to difference in growth irradiance or high light treatment were seen. The changes observed in the phosphoglycolipids and neutral lipid composition of cell and thylakoid membrane of low, moderate and high light grown rice plants in response to high light, are probably the result of physiological changes in the rice plants, to sustain optimum structure and function of the cell and thylakoid membrane to maintain active physiological functions to endure high light conditions.

Abiotic stresses affect differently the intron splicing and expression of chloroplast genes in coffee plants (Coffea arabica) and rice (Oryza sativa).

PubMed

Nguyen Dinh, Sy; Sai, Than Zaw Tun; Nawaz, Ghazala; Lee, Kwanuk; Kang, Hunseung

2016-08-20

Despite the increasing understanding of the regulation of chloroplast gene expression in plants, the importance of intron splicing and processing of chloroplast RNA transcripts under stress conditions is largely unknown. Here, to understand how abiotic stresses affect the intron splicing and expression patterns of chloroplast genes in dicots and monocots, we carried out a comprehensive analysis of the intron splicing and expression patterns of chloroplast genes in the coffee plant (Coffea arabica) as a dicot and rice (Oryza sativa) as a monocot under abiotic stresses, including drought, cold, or combined drought and heat stresses. The photosynthetic activity of both coffee plants and rice seedlings was significantly reduced under all stress conditions tested. Analysis of the transcript levels of chloroplast genes revealed that the splicing of tRNAs and mRNAs in coffee plants and rice seedlings were significantly affected by abiotic stresses. Notably, abiotic stresses affected differently the splicing of chloroplast tRNAs and mRNAs in coffee plants and rice seedlings. The transcript levels of most chloroplast genes were markedly downregulated in both coffee plants and rice seedlings upon stress treatment. Taken together, these results suggest that coffee and rice plants respond to abiotic stresses via regulating the intron splicing and expression of different sets of chloroplast genes. Copyright © 2016 Elsevier GmbH. All rights reserved.

Microbial Community Structure in the Rhizosphere of Rice Plants

PubMed Central

Breidenbach, Björn; Pump, Judith; Dumont, Marc G.

2016-01-01

The microbial community in the rhizosphere environment is critical for the health of land plants and the processing of soil organic matter. The objective of this study was to determine the extent to which rice plants shape the microbial community in rice field soil over the course of a growing season. Rice (Oryza sativa) was cultivated under greenhouse conditions in rice field soil from Vercelli, Italy and the microbial community in the rhizosphere of planted soil microcosms was characterized at four plant growth stages using quantitative PCR and 16S rRNA gene pyrotag analysis and compared to that of unplanted bulk soil. The abundances of 16S rRNA genes in the rice rhizosphere were on average twice that of unplanted bulk soil, indicating a stimulation of microbial growth in the rhizosphere. Soil environment type (i.e., rhizosphere versus bulk soil) had a greater effect on the community structure than did time (e.g., plant growth stage). Numerous phyla were affected by the presence of rice plants, but the strongest effects were observed for Gemmatimonadetes, Proteobacteria, and Verrucomicrobia. With respect to functional groups of microorganisms, potential iron reducers (e.g., Geobacter, Anaeromyxobacter) and fermenters (e.g., Clostridiaceae, Opitutaceae) were notably enriched in the rhizosphere environment. A Herbaspirillum species was always more abundant in the rhizosphere than bulk soil and was enriched in the rhizosphere during the early stage of plant growth. PMID:26793175

Systematic Analysis of Zn2Cys6 Transcription Factors Required for Development and Pathogenicity by High-Throughput Gene Knockout in the Rice Blast Fungus

PubMed Central

Huang, Pengyun; Lin, Fucheng

2014-01-01

Because of great challenges and workload in deleting genes on a large scale, the functions of most genes in pathogenic fungi are still unclear. In this study, we developed a high-throughput gene knockout system using a novel yeast-Escherichia-Agrobacterium shuttle vector, pKO1B, in the rice blast fungus Magnaporthe oryzae. Using this method, we deleted 104 fungal-specific Zn2Cys6 transcription factor (TF) genes in M. oryzae. We then analyzed the phenotypes of these mutants with regard to growth, asexual and infection-related development, pathogenesis, and 9 abiotic stresses. The resulting data provide new insights into how this rice pathogen of global significance regulates important traits in the infection cycle through Zn2Cys6TF genes. A large variation in biological functions of Zn2Cys6TF genes was observed under the conditions tested. Sixty-one of 104 Zn2Cys6 TF genes were found to be required for fungal development. In-depth analysis of TF genes revealed that TF genes involved in pathogenicity frequently tend to function in multiple development stages, and disclosed many highly conserved but unidentified functional TF genes of importance in the fungal kingdom. We further found that the virulence-required TF genes GPF1 and CNF2 have similar regulation mechanisms in the gene expression involved in pathogenicity. These experimental validations clearly demonstrated the value of a high-throughput gene knockout system in understanding the biological functions of genes on a genome scale in fungi, and provided a solid foundation for elucidating the gene expression network that regulates the development and pathogenicity of M. oryzae. PMID:25299517

Genomic instability related to zinc deficiency and excess in an in vitro model: is the upper estimate of the physiological requirements recommended for children safe?

PubMed

Padula, Gisel; Ponzinibbio, María Virginia; Gambaro, Rocío Celeste; Seoane, Analía Isabel

2017-08-01

Micronutrients are important for the prevention of degenerative diseases due to their role in maintaining genomic stability. Therefore, there is international concern about the need to redefine the optimal mineral and vitamin requirements to prevent DNA damage. We analyzed the cytostatic, cytotoxic, and genotoxic effect of in vitro zinc supplementation to determine the effects of zinc deficiency and excess and whether the upper estimate of the physiological requirement recommended for children is safe. To achieve zinc deficiency, DMEM/Ham's F12 medium (HF12) was chelated (HF12Q). Lymphocytes were isolated from healthy female donors (age range, 5-10 yr) and cultured for 7 d as follows: negative control (HF12, 60 μg/dl ZnSO 4 ); deficient (HF12Q, 12 μg/dl ZnSO 4 ); lower level (HF12Q + 80 μg/dl ZnSO 4 ); average level (HF12Q + 180 μg/dl ZnSO 4 ); upper limit (HF12Q + 280 μg/dl ZnSO 4 ); and excess (HF12Q + 380 μg/dl ZnSO 4 ). The comet (quantitative analysis) and cytokinesis-block micronucleus cytome assays were used. Differences were evaluated with Kruskal-Wallis and ANOVA (p < 0.05). Olive tail moment, tail length, micronuclei frequency, and apoptotic and necrotic percentages were significantly higher in the deficient, upper limit, and excess cultures compared with the negative control, lower, and average limit ones. In vitro zinc supplementation at the lower and average limit (80 and 180 μg/dl ZnSO 4 ) of the physiological requirement recommended for children proved to be the most beneficial in avoiding genomic instability, whereas the deficient, upper limit, and excess (12, 280, and 380 μg/dl) cultures increased DNA and chromosomal damage and apoptotic and necrotic frequencies.

Enhanced degradation of chlorpyrifos in rice (Oryza sativa L.) by five strains of endophytic bacteria and their plant growth promotional ability.

PubMed

Feng, Fayun; Ge, Jing; Li, Yisong; He, Shuang; Zhong, Jianfeng; Liu, Xianjing; Yu, Xiangyang

2017-10-01

Endophytic bacteria reside in plant tissues, such as roots, stems, leaves and seeds. Most of them can stimulate plant growth or alleviate phytotoxicity of pollutants. There are handful species with dual functions stimulating plant growth and degrading pollutants have been reported. Five endophytic bacteria were isolated from chlorpyrifos (CP) treated rice plants and identified as Pseudomonas aeruginosa strain RRA, Bacillus megaterium strain RRB, Sphingobacterium siyangensis strain RSA, Stenotrophomonas pavanii strain RSB and Curtobacterium plantarum strain RSC according to morphological characteristics, physiological and biochemical tests, and 16S rDNA phylogeny. All of them possessed some plant growth promotional traits, including indole acetic acid and siderophore production, secretion of phosphate solubilization and 1-aminocyclopropane-1-carboxylate deaminase. The bacteria were marked with the green fluorescent protein (gfp) gene and successfully colonized into rice plants. All isolates were able to degrade CP in vitro and in vivo. The five isolates degraded more than 90% of CP in 24 h when the initial concentration was lower than 5 mg/L. CP degradation was significantly enhanced in the infested rice plants and rice grains. The final CP residual was reduced up to 80% in the infested rice grains compared to the controls. The results indicate that these isolates are promising bio-inoculants for the removal or detoxification of CP residues in rice plants and grains. Copyright © 2017 Elsevier Ltd. All rights reserved.

Convergent or parallel molecular evolution of momilactone A and B: potent allelochemicals, momilactones have been found only in rice and the moss Hypnum plumaeforme.

PubMed

Kato-Noguchi, Hisashi

2011-09-01

Plant second metabolites momilactone A and B, which act as potent phytoalexins and allelochemicals, have been found thus far only in rice and the moss Hypnum plumaeforme, although both plants are taxonomically quite distinct. The concentrations of momilactone A and B, respectively, in rice plants were 4.5-140 and 2.9-85μg/g, and those in H. plumaeforme were 8.4-58.7 and 4.2-23.4μg/g. Momilactone A and B concentrations in rice and H. plumaeforme plants were increased by UV irradiation, elicitor and jasmonic acid treatments. Rice and H. plumaeforme plants secrete momilactone A and B into the rhizosphere, and the secretion level was also increased by UV irradiation, elicitor and jasmonic acid treatments. In addition, although endogenous concentrations of momilactone A in rice and H. plumaeforme were greater than those of momilactone B, the secretion levels of momilactone B were greater than those of momilactone A in rice and H. plumaeforme, which suggests that momilactone B may be selectively secreted by both rice and H. plumaeforme. As momilactone A and B exert potent antifungal and growth inhibitory activities, momilactone A and B may play an important role in the defense responses in H. plumaeforme and rice against pathogen infections and in allelopathy. The secretion of momilactone A and B into the rhizosphere may also prevent bacterial and fungal infections and provide a competitive advantage for nutrients through the inhibition of invading root systems of neighboring plants as allelochemicals. Therefore, both plants, despite their evolutionary distance, may use same defense strategy with respect to the momilactone A and B production and secretion, which resulting from convergent or parallel evolutionary processes. In the case of parallel evolution, there may be plant species providing the missing link in molecular evolution of momilactones between H. plumaeforme and rice. Copyright © 2011 Elsevier GmbH. All rights reserved.

Interactions of iron with manganese, zinc, chromium, and selenium as related to prophylaxis and treatment of iron deficiency.

PubMed

Bjørklund, Geir; Aaseth, Jan; Skalny, Anatoly V; Suliburska, Joanna; Skalnaya, Margarita G; Nikonorov, Alexandr A; Tinkov, Alexey A

2017-05-01

Iron (Fe) deficiency is considered as the most common nutritional deficiency. Iron deficiency is usually associated with low Fe intake, blood loss, diseases, poor absorption, gastrointestinal parasites, or increased physiological demands as in pregnancy. Nutritional Fe deficiency is usually treated with Fe tablets, sometimes with Fe-containing multimineral tablets. Trace element interactions may have a significant impact on Fe status. Existing data demonstrate a tight interaction between manganese (Mn) and Fe, especially in Fe-deficient state. The influence of Mn on Fe homeostasis may be mediated through its influence on Fe absorption, circulating transporters like transferrin, and regulatory proteins. The existing data demonstrate that the influence of zinc (Zn) on Fe status may be related to their competition for metal transporters. Moreover, Zn may be involved in regulation of hepcidin production. At the same time, human data on the interplay between Fe and Zn especially in terms of Fe-deficiency and supplementation are contradictory, demonstrating both positive and negative influence of Zn on Fe status. Numerous data also demonstrate the possibility of competition between Fe and chromium (Cr) for transferrin binding. At the same time, human data on the interaction between these metals are contradictory. Therefore, while managing hypoferremia and Fe-deficiency anemia, it is recommended to assess the level of other trace elements in parallel with indices of Fe homeostasis. It is supposed that simultaneous correction of trace element status in Fe deficiency may help to decrease possible antagonistic or increase synergistic interactions. Copyright © 2017 Elsevier GmbH. All rights reserved.

Understanding the molecular basis of plant growth promotional effect of Pseudomonas fluorescens on rice through protein profiling.

PubMed

Kandasamy, Saveetha; Loganathan, Karthiba; Muthuraj, Raveendran; Duraisamy, Saravanakumar; Seetharaman, Suresh; Thiruvengadam, Raguchander; Ponnusamy, Balasubramanian; Ramasamy, Samiyappan

2009-12-24

Plant Growth Promoting Rhizobacteria (PGPR), Pseudomonas fluorescens strain KH-1 was found to exhibit plant growth promotional activity in rice under both in-vitro and in-vivo conditions. But the mechanism underlying such promotional activity of P. fluorescens is not yet understood clearly. In this study, efforts were made to elucidate the molecular responses of rice plants to P. fluorescens treatment through protein profiling. Two-dimensional polyacrylamide gel electrophoresis strategy was adopted to identify the PGPR responsive proteins and the differentially expressed proteins were analyzed by mass spectrometry. Priming of P. fluorescens, 23 different proteins found to be differentially expressed in rice leaf sheaths and MS analysis revealed the differential expression of some important proteins namely putative p23 co-chaperone, Thioredoxin h- rice, Ribulose-bisphosphate carboxylase large chain precursor, Nucleotide diPhosphate kinase, Proteosome sub unit protein and putative glutathione S-transferase protein. Functional analyses of the differential proteins were reported to be directly or indirectly involved in growth promotion in plants. Thus, this study confirms the primary role of PGPR strain KH-1 in rice plant growth promotion.

The method for detecting biological parameter of rice growth and early planting of paddy crop by using multi temporal remote sensing data

NASA Astrophysics Data System (ADS)

Domiri, D. D.

2017-01-01

Rice crop is the most important food crop for the Asian population, especially in Indonesia. During the growth of rice plants have four main phases, namely the early planting or inundation phase, the vegetative phase, the generative phase, and bare land phase. Monitoring the condition of the rice plant needs to be conducted in order to know whether the rice plants have problems or not in its growth. Application of remote sensing technology, which uses satellite data such as Landsat 8 and others which has a spatial and temporal resolution is high enough for monitoring the condition of crops such as paddy crop in a large area. In this study has been made an algorithm for monitoring rapidly of rice growth condition using Maximum of Vegetation Index (EVI Max). The results showed that the time of early planting can be estimated if known when EVI Max occurred. The value of EVI Max and when it occured can be known by trough spatial analysis of multitemporal EVI Landsat 8 or other medium spatial resolution satellites.

Gene flow from weedy red rice (Oryza sativa L.) to cultivated rice and fitness of hybrids.

PubMed

Shivrain, Vinod K; Burgos, Nilda R; Gealy, David R; Sales, Marites A; Smith, Kenneth L

2009-10-01

Gene transfer from weeds to crops could produce weedy individuals that might impact upon the evolutionary dynamics of weedy populations, the persistence of escaped genes in agroecosystems and approaches to weed management and containment of transgenic crops. The present aim was to quantify the gene flowrate from weedy red rice to cultivated rice, and evaluate the morphology, phenology and fecundity of resulting hybrids. Field experiments were conducted at Stuttgart and Rohwer, Arkansas, USA. Twelve red rice accessions and an imazethapyr-resistant rice (Imi-R; Clearfield) were used. Hybrids between Imi-R rice x red rice were 138-150 cm tall and flowered 1-5 days later than the rice parent, regardless of the red rice parent. Hybrids produced 20-50% more seed than the rice parent, but had equivalent seed production to the majority of red rice parents. Seeds of all hybrids were red, pubescent and dehisced at maturity. For the majority of hybrids, seed germination was higher than that of the red rice parent. The gene flowrate from red rice to rice was 0.01-0.2% and differed by red rice biotype. The hybrids had higher fecundity and potential competitive ability than the rice parent, and in some cases also the red rice parent. Red rice plants are vectors of gene flow back to cultivated rice and other weedy populations. The progeny of red rice hybrids from cultivated rice mother plants have higher chances of persistence than those from red rice mother plants. Gene flow mitigation strategies should consider this scenario. Copyright 2009 Society of Chemical Industry.

Arbuscular mycorrhizal symbiosis ameliorates the optimum quantum yield of photosystem II and reduces non-photochemical quenching in rice plants subjected to salt stress.

PubMed

Porcel, Rosa; Redondo-Gómez, Susana; Mateos-Naranjo, Enrique; Aroca, Ricardo; Garcia, Rosalva; Ruiz-Lozano, Juan Manuel

2015-08-01

Rice is the most important food crop in the world and is a primary source of food for more than half of the world population. However, salinity is considered the most common abiotic stress reducing its productivity. Soil salinity inhibits photosynthetic processes, which can induce an over-reduction of the reaction centres in photosystem II (PSII), damaging the photosynthetic machinery. The arbuscular mycorrhizal (AM) symbiosis may improve host plant tolerance to salinity, but it is not clear how the AM symbiosis affects the plant photosynthetic capacity, particularly the efficiency of PSII. This study aimed at determining the influence of the AM symbiosis on the performance of PSII in rice plants subjected to salinity. Photosynthetic activity, plant gas-exchange parameters, accumulation of photosynthetic pigments and rubisco activity and gene expression were also measured in order to analyse comprehensively the response of the photosynthetic processes to AM symbiosis and salinity. Results showed that the AM symbiosis enhanced the actual quantum yield of PSII photochemistry and reduced the quantum yield of non-photochemical quenching in rice plants subjected to salinity. AM rice plants maintained higher net photosynthetic rate, stomatal conductance and transpiration rate than nonAM plants. Thus, we propose that AM rice plants had a higher photochemical efficiency for CO2 fixation and solar energy utilization and this increases plant salt tolerance by preventing the injury to the photosystems reaction centres and by allowing a better utilization of light energy in photochemical processes. All these processes translated into higher photosynthetic and rubisco activities in AM rice plants and improved plant biomass production under salinity. Copyright © 2015 Elsevier GmbH. All rights reserved.

Effects of long-term fertilization practices on heavy metal cadmium accumulation in the surface soil and rice plants of double-cropping rice system in Southern China.

PubMed

Xu, Yilan; Tang, Haiming; Liu, Tangxing; Li, Yifeng; Huang, Xinjie; Pi, Jun

2018-05-08

Fertilizer regime is playing an important role in heavy metal cadmium (Cd) accumulation in paddy soils and crop plant. It is necessary to assess the Cd accumulation in soils and rice (Oryza sativa L.) plants under long-term fertilization managements, and the results which help to assess the environmental and food risk in Southern China. However, the effects of different organic manure and chemical fertilizers on Cd accumulation in soils and rice plant remain unclear under intensively cultivated rice conditions. Therefore, the objective was to explore Cd accumulation in paddy soils and rice plant at mature stage under different long-term fertilization managements in the double-cropping rice system. Cd accumulation in the surface soils (0-20 cm) and rice plant with chemical fertilizer alone (MF), rice straw residue and chemical fertilizer (RF), 30% organic matter and 70% chemical fertilizer (LOM), 60% organic matter and 40% chemical fertilizer (HOM), and without fertilizer input (CK) basis on 32 years long-term fertilization experiment were analyzed. The results showed that the soil total Cd content was increased by 0.296 and 0.351 mg kg -1 and 0.261 and 0.340 mg kg -1 under LOM and HOM treatments at early and late rice mature stages, respectively, compared with the CK treatment. And the soil available Cd content was increased by 0.073 and 0.137 mg kg -1 and 0.102 and 0.160 mg kg -1 under LOM and HOM treatments at early and late rice mature stages, respectively, compared with the CK treatment. The bioconcentration factor of Cd across different parts of rice plant was the highest in root, followed by stem and grain, and the lowest in leaves. At early and late rice mature stages, the root Cd concentration of rice plant was increased by 0.689 and 0.608 mg kg -1 with HOM treatment, the stem Cd concentration of rice plant was increased by 0.666 and 0.758 mg kg -1 with RF treatment, and the leaf and grain Cd concentration of rice plant was increased 0.094 and 0.082 mg kg -1 and 0.086 and 0.083 mg kg -1 with LOM treatment, respectively, compared with the CK treatment. The soil Cd single-factor contaminant index (P Cd ) under different fertilization treatments was as the following HOM > LOM > RF > MF > CK. Meanwhile, the P Cd with LOM and HOM treatments was higher than that of the MF, RF, and CK treatments, but there is no significant difference between that of MF and RF treatments. Therefore, long-term application of rice straw residue and chemical fertilizer had no obvious effect on the accumulation of Cd in paddy soils and grain, and soil Cd accumulation was increased as application of organic fertilizer.

Progress and challenges in improving the nutritional quality of rice (Oryza sativa L.).

PubMed

Birla, Deep Shikha; Malik, Kapil; Sainger, Manish; Chaudhary, Darshna; Jaiwal, Ranjana; Jaiwal, Pawan K

2017-07-24

Rice is a staple food for more than 3 billion people in more than 100 countries of the world but ironically it is deficient in many bioavailable vitamins, minerals, essential amino- and fatty-acids and phytochemicals that prevent chronic diseases like type 2 diabetes, heart disease, cancers, and obesity. To enhance the nutritional and other quality aspects of rice, a better understanding of the regulation of the processes involved in the synthesis, uptake, transport, and metabolism of macro-(starch, seed storage protein and lipid) and micronutrients (vitamins, minerals and phytochemicals) is required. With the publication of high quality genomic sequence of rice, significant progress has been made in identification, isolation, and characterization of novel genes and their regulation for the nutritional and quality enhancement of rice. During the last decade, numerous efforts have been made to refine the nutritional and other quality traits either by using the traditional breeding with high through put technologies such as marker assisted selection and breeding, or by adopting the transgenic approach. A significant improvement in vitamins (A, folate, and E), mineral (iron), essential amino acid (lysine), and flavonoids levels has been achieved in the edible part of rice, i.e., endosperm (biofortification) to meet the daily dietary allowance. However, studies on bioavailability and allergenicity on biofortified rice are still required. Despite the numerous efforts, the commercialization of biofortified rice has not yet been achieved. The present review summarizes the progress and challenges of genetic engineering and/or metabolic engineering technologies to improve rice grain quality, and presents the future prospects in developing nutrient dense rice to save the everincreasing population, that depends solely on rice as the staple food, from widespread nutritional deficiencies.

Herbivory by resident geese: The loss and recovery of wild rice along the tidal Patuxent River

USGS Publications Warehouse

Haramis, G.M.; Kearns, G.D.

2007-01-01

Well known for a fall spectacle of maturing wild rice (Zizania aquatica) and migrant waterbirds, the tidal freshwater marshes of the Patuxent River, Maryland, USA, experienced a major decline in wild rice during the 1990s. We conducted experiments in 1999 and 2000 with fenced exclosures and discovered herbivory by resident Canada geese (Branta canadensis). Grazing by geese eliminated rice outside exclosures, whereas protected plants achieved greater size, density, and produced more panicles than rice occurring in natural stands. The observed loss of rice on the Patuxent River reflects both the sensitivity of this annual plant to herbivory and the destructive nature of an overabundance of resident geese on natural marsh vegetation. Recovery of rice followed 2 management actions: hunting removal of approximately 1,700 geese during a 4-year period and reestablishment of rice through a large-scale fencing and planting program.

Good manufacturing practices production of a purification-free oral cholera vaccine expressed in transgenic rice plants.

PubMed

Kashima, Koji; Yuki, Yoshikazu; Mejima, Mio; Kurokawa, Shiho; Suzuki, Yuji; Minakawa, Satomi; Takeyama, Natsumi; Fukuyama, Yoshiko; Azegami, Tatsuhiko; Tanimoto, Takeshi; Kuroda, Masaharu; Tamura, Minoru; Gomi, Yasuyuki; Kiyono, Hiroshi

2016-03-01

The first Good Manufacturing Practices production of a purification-free rice-based oral cholera vaccine (MucoRice-CTB) from transgenic plants in a closed cultivation system yielded a product meeting regulatory requirements. Despite our knowledge of their advantages, plant-based vaccines remain unavailable for human use in both developing and industrialized countries. A leading, practical obstacle to their widespread use is producing plant-based vaccines that meet governmental regulatory requirements. Here, we report the first production according to current Good Manufacturing Practices of a rice-based vaccine, the cholera vaccine MucoRice-CTB, at an academic institution. To this end, we established specifications and methods for the master seed bank (MSB) of MucoRice-CTB, which was previously generated as a selection-marker-free line, evaluated its propagation, and given that the stored seeds must be renewed periodically. The production of MucoRice-CTB incorporated a closed hydroponic system for cultivating the transgenic plants, to minimize variations in expression and quality during vaccine manufacture. This type of molecular farming factory can be operated year-round, generating three harvests annually, and is cost- and production-effective. Rice was polished to a ratio of 95 % and then powdered to produce the MucoRice-CTB drug substance, and the identity, potency, and safety of the MucoRice-CTB product met pre-established release requirements. The formulation of MucoRice-CTB made by fine-powdering of drug substance and packaged in an aluminum pouch is being evaluated in a physician-initiated phase I study.

Prediction of methyl mercury uptake by rice plants ( Oryza sativa L.) using the diffusive gradient in thin films technique.

PubMed

Liu, Jinling; Feng, Xinbin; Qiu, Guangle; Anderson, Christopher W N; Yao, Heng

2012-10-16

Rice consumption is the primary pathway for methyl mercury (MeHg) exposure at inland mercury (Hg) mining areas of SW China. Mechanistic information on MeHg accumulation in rice is, however, limited. The process of MeHg exchange between paddy soil and rice plants predominantly occurs in pore water. The detection of bioavailable MeHg in pore water is therefore important to predict MeHg uptake by rice plants ( Oryza sativa L.). This study investigated MeHg dynamics and spatial MeHg trends in pore water during the rice growing season using the diffusive gradient in thin films (DGT) technique and tested the ability of DGT to predict MeHg uptake by rice. The MeHg uptake flux from soil to rice plants via roots was significantly correlated with the DGT-measured MeHg flux (R = 0.853, p < 0.01). Our study implies that DGT can predict the bioavailability of MeHg in rice paddy soil and that the DGT method can provide quantitative description of the rate of uptake of this bioavailable MeHg. The DGT technique is demonstrated as a useful indicator of the likely ecotoxicological risk that might be apparent where paddy rice is grown in MeHg contaminated soil.

Phloem-exudate proteome analysis of response to insect brown plant-hopper in rice.

PubMed

Du, Ba; Wei, Zhe; Wang, Zhanqi; Wang, Xiaoxiao; Peng, Xinxin; Du, Bo; Chen, Rongzhi; Zhu, Lili; He, Guangcun

2015-07-01

Brown plant-hopper (Nilaparvata lugens Stål, BPH), one of the most devastating agricultural insect pests of rice throughout Asia, ingests nutrients from rice sieve tubes and causes a dramatic yield loss. Planting resistant variety is an efficient and economical way to control this pest. Understanding the mechanisms of host resistance is extremely valuable for molecular design of resistant rice variety. Here, we used an iTRAQ-based quantitative proteomics approach to perform analysis of protein expression profiles in the phloem exudates of BPH-resistant and susceptible rice plants following BPH infestation. A total of 238 proteins were identified, most of which were previously described to be present in the phloem of rice and other plants. The expression of genes for selected proteins was confirmed using a laser capture micro-dissection method and RT-PCR. The mRNAs for three proteins, RGAP, TCTP, and TRXH, were further analyzed by using in situ mRNA hybridization and localized in the phloem cells. Our results showed that BPH feeding induced significant changes in the abundance of proteins in phloem sap of rice involved in multiple pathways, including defense signal transduction, redox regulation, and carbohydrate and protein metabolism, as well as cell structural proteins. The results presented provide new insights into rice resistance mechanisms and should facilitate the breeding of novel elite BPH-resistant rice varieties. Copyright © 2015 Elsevier GmbH. All rights reserved.

Azospirillum and arbuscular mycorrhizal colonization enhance rice growth and physiological traits under well-watered and drought conditions.

PubMed

Ruíz-Sánchez, Michel; Armada, Elisabet; Muñoz, Yaumara; García de Salamone, Inés E; Aroca, Ricardo; Ruíz-Lozano, Juan Manuel; Azcón, Rosario

2011-07-01

The response of rice plants to inoculation with an arbuscular mycorrhizal (AM) fungus, Azospirillum brasilense, or combination of both microorganisms, was assayed under well-watered or drought stress conditions. Water deficit treatment was imposed by reducing the amount of water added, but AM plants, with a significantly higher biomass, received the same amount of water as non-AM plants, with a poor biomass. Thus, the water stress treatment was more severe for AM plants than for non-AM plants. The results showed that AM colonization significantly enhanced rice growth under both water conditions, although the greatest rice development was reached in plants dually inoculated under well-watered conditions. Water level did not affect the efficiency of photosystem II, but both AM and A. brasilense inoculations increased this value. AM colonization increased stomatal conductance, particularly when associated with A. brasilense, which enhanced this parameter by 80% under drought conditions and by 35% under well-watered conditions as compared to single AM plants. Exposure of AM rice to drought stress decreased the high levels of glutathione that AM plants exhibited under well-watered conditions, while drought had no effect on the ascorbate content. The decrease of glutathione content in AM plants under drought stress conditions led to enhance lipid peroxidation. On the other hand, inoculation with the AM fungus itself increased ascorbate and proline as protective compounds to cope with the harmful effects of water limitation. Inoculation with A. brasilense also enhanced ascorbate accumulation, reaching a similar level as in AM plants. These results showed that, in spite of the fact that drought stress imposed by AM treatments was considerably more severe than non-AM treatments, rice plants benefited not only from the AM symbiosis but also from A. brasilense root colonization, regardless of the watering level. However, the beneficial effects of A. brasilense on most of the physiological and biochemical traits of rice plants were only clearly visible when the plants were mycorrhized. This microbial consortium was effective for rice plants as an acceptable and ecofriendly technology to improve plant performance and development. Copyright © 2011 Elsevier GmbH. All rights reserved.

Homologous expression of cytosolic dehydroascorbate reductase increases grain yield and biomass under paddy field conditions in transgenic rice (Oryza sativa L. japonica).

PubMed

Kim, Young-Saeng; Kim, Il-Sup; Bae, Mi-Jung; Choe, Yong-Hoe; Kim, Yul-Ho; Park, Hyang-Mi; Kang, Hong-Gyu; Yoon, Ho-Sung

2013-06-01

Dehydroascorbate reductase (DHAR, EC 1.8.5.1) maintains redox pools of ascorbate (AsA) by recycling oxidized AsA to reduced AsA. To investigate whether DHAR affects rice yield under normal environmental conditions, cDNA-encoding DHAR (OsDHAR1) was isolated from rice and used to develop OsDHAR1-overexpressing transgenic rice plants, under the regulation of a maize ubiquitin promoter. Incorporation and expression of the transgene in transgenic rice plants was confirmed by genomic polymerase chain reaction (PCR), semi-quantitative reverse transcription PCR (RT-PCR), western blot, and enzyme activity. The expression levels were at least twofold higher in transgenic (TG) rice plants than in control wild-type (WT) rice plants. In addition, OsDHAR1-overexpression in seven-independent homologous transgenic plants, as compared to WT plants, increased photosynthetic capacity and antioxidant enzyme activities under paddy field conditions, which led to an improved AsA pool and redox homeostasis. Furthermore, OsDHAR1 overexpression significantly improved grain yield and biomass due to the increase of culm and root weights and to enhance panicle and spikelet numbers in the same seven independent TG rice plants during the farming season (2010 and 2011) in South Korea. The OsDHAR protein contained the redox-active site (Cys20), as well as the conserved GSH-binding region, GSH-binding motif, glutathione-S-transferase (GST) N-terminal domain, C-terminal domain interface, and GST C-terminal domain. Therefore, our results indicate that OsDHAR1 overexpression, capable of functioning in AsA recycling, and protein folding increases environmental adaptation to paddy field conditions by the improving AsA pool and redox homeostasis, which enhances rice grain yield and biomass.

SET DOMAIN GROUP 708, a histone H3 lysine 36-specific methyltransferase, controls flowering time in rice (Oryza sativa).

PubMed

Liu, Bing; Wei, Gang; Shi, Jinlei; Jin, Jing; Shen, Ting; Ni, Ting; Shen, Wen-Hui; Yu, Yu; Dong, Aiwu

2016-04-01

As a key epigenetic modification, the methylation of histone H3 lysine 36 (H3K36) modulates chromatin structure and is involved in diverse biological processes. To better understand the language of H3K36 methylation in rice (Oryza sativa), we chose potential histone methylation enzymes for functional exploration. In particular, we characterized rice SET DOMAIN GROUP 708 (SDG708) as an H3K36-specific methyltransferase possessing the ability to deposit up to three methyl groups on H3K36. Compared with the wild-type, SDG708-knockdown rice mutants displayed a late-flowering phenotype under both long-day and short-day conditions because of the down-regulation of the key flowering regulatory genes Heading date 3a (Hd3a), RICE FLOWERING LOCUS T1 (RFT1), and Early heading date 1 (Ehd1). Chromatin immunoprecipitation experiments indicated that H3K36me1, H3K36me2, and H3K36me3 levels were reduced at these loci in SDG708-deficient plants. More importantly, SDG708 was able to directly target and effect H3K36 methylation on specific flowering genes. In fact, knockdown of SDG708 led to misexpression of a set of functional genes and a genome-wide decrease in H3K36me1/2/3 levels during the early growth stages of rice. SDG708 is a methyltransferase that catalyses genome-wide deposition of all three methyl groups on H3K36 and is involved in many biological processes in addition to flowering promotion. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Serum zinc concentration in cystic fibrosis patients with CFTR I1234V mutation associated with pancreatic sufficiency.

PubMed

AbdulWahab, Atqah; Abushahin, Ahmed; Allangawi, Mona; Chandra, Prem; Abdel Rahman, Mohamed Osman; Soliman, Ashraf

2017-05-01

To determine serum zinc (Zn) level among cystic fibrosis (CF) patients with homozygous CFTR I1234V mutation associated with pancreatic sufficiency (PS). A cross-sectional study was conducted including both pediatric and adult CF patients. Data on age, weight, height, body mass index (BMI), BMI Z-score, FEV1, and chronic Pseudomonas aeruginosa infection were collected. Serum Zn, albumin, and total proteins were measured and analyzed. Forty-five CF patients with homozygous CFTR I1234V mutation belonging to a large Arab kindred tribe and eight CF patients with other mutations associated with pancreatic insufficiency (PI). Patient's age ranged from 2 to 49 years with a mean age of 15.1 ± 9.1 years and mean plasma Zn of 0.78 ± 0.15 mcg/mL. Seven (13.2%) patients with CFTR I1234V and PS had low Zn levels (<0.6 mcg/mL). Mean age among Zn deficient group was significantly older. The mean FEV1 in the deficient group was found to be insignificant low. Persistent P. aeruginosa colonization was more prevalent in Zn deficient group. BMI Z-scosre of CF patients were positively correlated with Zn levels. Forty-five healthy subjects belonging to the same Arab tribe were selected in order to assess their Zn levels and their mean plasma Zn of 0.84 ± 0.11 mcg/mL (range 0.65-1.1 mcg/mL) with mean age 20.4 ± 10.1 years (range 6-40 years). These findings suggest that Zn deficiency can occur in CF patients with PS. The association of Zn levels and the frequency of P. aeruginosa isolated in CF patients need further investigation. © 2015 The Authors. The Clinical Respiratory Journal Published by John Wiley & Sons Ltd.

A Rice Gene Homologous to Arabidopsis AGD2-LIKE DEFENSE1 Participates in Disease Resistance Response against Infection with Magnaporthe oryzae.

PubMed

Jung, Ga Young; Park, Ju Yeon; Choi, Hyo Ju; Yoo, Sung-Je; Park, Jung-Kwon; Jung, Ho Won

2016-08-01

ALD1 (ABERRANT GROWTH AND DEATH2 [AGD2]-LIKE DEFENSE1) is one of the key defense regulators in Arabidopsis thaliana and Nicotiana benthamiana. In these model plants, ALD1 is responsible for triggering basal defense response and systemic resistance against bacterial infection. As well ALD1 is involved in the production of pipecolic acid and an unidentified compound(s) for systemic resistance and priming syndrome, respectively. These previous studies proposed that ALD1 is a potential candidate for developing genetically modified (GM) plants that may be resistant to pathogen infection. Here we introduce a role of ALD1-LIKE gene of Oryza sativa, named as OsALD1, during plant immunity. OsALD1 mRNA was strongly transcribed in the infected leaves of rice plants by Magnaporthe oryzae, the rice blast fungus. OsALD1 proteins predominantly localized at the chloroplast in the plant cells. GM rice plants over-expressing OsALD1 were resistant to the fungal infection. The stable expression of OsALD1 also triggered strong mRNA expression of PATHOGENESIS-RELATED PROTEIN1 genes in the leaves of rice plants during infection. Taken together, we conclude that OsALD1 plays a role in disease resistance response of rice against the infection with rice blast fungus.

Immunity to Rice black streaked dwarf virus, a plant reovirus, can be achieved in rice plants by RNA silencing against the gene for the viroplasm component protein.

PubMed

Shimizu, Takumi; Nakazono-Nagaoka, Eiko; Akita, Fusamichi; Uehara-Ichiki, Tamaki; Omura, Toshihiro; Sasaya, Takahide

2011-09-01

The nonstructural protein P9-1 of Rice black streaked dwarf virus has been confirmed to accumulate in viroplasms, the putative sites of viral replication, in infected plants and insects. We transformed rice plants by introducing an RNA interference construct against the P9-1-encoding gene. The resultant transgenic plants accumulated short interfering RNAs specific to the construct. All progenies produced by self-fertilization of these transgenic plants with induced RNA interference against the gene for P9-1 were resistant to infection by the virus. Our results demonstrated that interfering with the expression of a viroplasm component protein of plant reoviruses, which plays an important role in viral proliferation, might be a practical and effective way to control plant reovirus infection in crop plants. Copyright © 2011 Elsevier B.V. All rights reserved.

A Method for Selective Depletion of Zn(II) Ions from Complex Biological Media and Evaluation of Cellular Consequences of Zn(II) Deficiency

PubMed Central

Richardson, Christopher E. R.; Cunden, Lisa S.; Butty, Vincent L.; Nolan, Elizabeth M.; Lippard, Stephen J.; Shoulders, Matthew D.

2018-01-01

We describe the preparation, evaluation, and application of an S100A12 protein-conjugated solid support, hereafter the “A12-resin,” that can remove 99% of Zn(II) from complex biological solutions without significantly perturbing the concentrations of other metal ions. The A12-resin can be applied to selectively deplete Zn(II) from diverse tissue culture media and from other biological fluids, including human serum. To further demonstrate the utility of this approach, we investigated metabolic, transcriptomic, and metallomic responses of HEK293 cells cultured in medium depleted of Zn(II) using S100A12. The resulting data provide insight into how cells respond to acute Zn(II) deficiency. We expect that the A12-resin will facilitate interrogation of disrupted Zn(II) homeostasis in biological settings, uncovering novel roles for Zn(II) in biology. PMID:29334734

Rice straw addition as sawdust substitution in oyster mushroom (Pleurotus ostreatus) planted media

NASA Astrophysics Data System (ADS)

Utami, Christine Pamardining; Susilawati, Puspita Ratna

2017-08-01

Oyster mushroom is favorite by the people because of the high nutrients. The oyster mushroom cultivation usually using sawdust. The availability of sawdust become difficult to find. It makes difficulties of mushroom cultivation. Rice straw as an agricultural waste can be used as planted media of oyster mushroom because they contain much nutrition needed to the mushroom growth. The aims of this research were to analysis the influence of rice straw addition in a baglog as planted media and to analysis the concentration of rice straw addition which can substitute sawdust in planted media of oyster mushroom. This research used 4 treatment of sawdust and rice straw ratio K = 75 % : 0 %, P1 = 60 % : 15 %, P2 = 40 % : 35 %, P3 = 15 % : 60 %. The same material composition of all baglog was bran 20%, chalk 5%, and water 70%. The parameters used in this research were wet weight, dry weight, moisture content and number of the mushroom fruit body. Data analysis was used ANOVA test with 1 factorial. The results of this research based on statistical analysis showed that there was no influence of rice straw addition in a planted media on the oyster mushroomgrowth. 15% : 60% was the concentrationof rice straw additionwhich can substitute the sawdust in planted media of oyster mushroom.

Constitutive expression of CaPLA1 conferred enhanced growth and grain yield in transgenic rice plants.

PubMed

Park, Ki Youl; Kim, Eun Yu; Seo, Young Sam; Kim, Woo Taek

2016-03-01

Phospholipids are not only important components of cell membranes, but participate in diverse processes in higher plants. In this study, we generated Capsicum annuum phospholipiase A1 (CaPLA1) overexpressing transgenic rice (Oryza sativa L.) plants under the control of the maize ubiquitin promoter. The T4 CaPLA1-overexpressing rice plants (Ubi:CaPLA1) had a higher root:shoot mass ratio than the wild-type plants in the vegetative stage. Leaf epidermal cells from transgenic plants had more cells than wild-type plants. Genes that code for cyclin and lipid metabolic enzymes were up-regulated in the transgenic lines. When grown under typical paddy field conditions, the transgenic plants produced more tillers, longer panicles and more branches per panicle than the wild-type plants, all of which resulted in greater grain yield. Microarray analysis suggests that gene expressions that are related with cell proliferation, lipid metabolism, and redox state were widely altered in CaPLA1-overexpressing transgenic rice plants. Ubi:CaPLA1 plants had a reduced membrane peroxidation state, as determined by malondialdehyde and conjugated diene levels and higher peroxidase activity than wild-type rice plants. Furthermore, three isoprenoid synthetic genes encoding terpenoid synthase, hydroxysteroid dehydrogenase and 3-hydroxy-3-methyl-glutaryl-CoA reductase were up-regulated in CaPLA1-overexpressing plants. We suggest that constitutive expression of CaPLA1 conferred increased grain yield with enhanced growth in transgenic rice plants by alteration of gene activities related with cell proliferation, lipid metabolism, membrane peroxidation state and isoprenoid biosynthesis.

AmeriFlux US-Twt Twitchell Island

DOE Data Explorer

Baldocchi, Dennis [University of California, Berkeley

2016-01-01

This is the AmeriFlux version of the carbon flux data for the site US-Twt Twitchell Island. Site Description - The Twitchell Island site is a rice paddy that is owned by the state and managed by the California Department of Water Resources. While Bare Peat field was leveled for rice planting, the tower was installed on April 3, 2009. The rice paddy was converted from corn in 2007. In Summer 2009, Bispyribac-sodium and Pendimethalin herbicides were applied to the fields prior to rice planting and flooding, then pesticide and fertilizer application took place. Each year after rice is planted in the spring by drilling, the field is flooded. Then, the field is drained in early fall, rice is harvested, and the field site is moved.

Transgenic strategies to confer resistance against viruses in rice plants

PubMed Central

Sasaya, Takahide; Nakazono-Nagaoka, Eiko; Saika, Hiroaki; Aoki, Hideyuki; Hiraguri, Akihiro; Netsu, Osamu; Uehara-Ichiki, Tamaki; Onuki, Masatoshi; Toki, Seichi; Saito, Koji; Yatou, Osamu

2014-01-01

Rice (Oryza sativa L.) is cultivated in more than 100 countries and supports nearly half of the world’s population. Developing efficient methods to control rice viruses is thus an urgent necessity because viruses cause serious losses in rice yield. Most rice viruses are transmitted by insect vectors, notably planthoppers and leafhoppers. Viruliferous insect vectors can disperse their viruses over relatively long distances, and eradication of the viruses is very difficult once they become widespread. Exploitation of natural genetic sources of resistance is one of the most effective approaches to protect crops from virus infection; however, only a few naturally occurring rice genes confer resistance against rice viruses. Many investigators are using genetic engineering of rice plants as a potential strategy to control viral diseases. Using viral genes to confer pathogen-derived resistance against crops is a well-established procedure, and the expression of various viral gene products has proved to be effective in preventing or reducing infection by various plant viruses since the 1990s. RNA interference (RNAi), also known as RNA silencing, is one of the most efficient methods to confer resistance against plant viruses on their respective crops. In this article, we review the recent progress, mainly conducted by our research group, in transgenic strategies to confer resistance against tenuiviruses and reoviruses in rice plants. Our findings also illustrate that not all RNAi constructs against viral RNAs are equally effective in preventing virus infection and that it is important to identify the viral “Achilles’ heel” gene to target for RNAi attack when engineering plants. PMID:24454308

Cerium enhances germination and shoot growth, and alters mineral nutrient concentration in rice

PubMed Central

García-Morales, Soledad; Pérez-Sato, Juan Antonio

2018-01-01

Cerium (Ce) belongs to the rare earth elements (REEs), and although it is not essential for plants, it can stimulate growth and other physiological processes. The objective of this research was to evaluate the effect of Ce on seed germination, initial seedling growth, and vegetative growth in rice (Oryza sativa L.) cv. Morelos A-98. During the germination process, the seeds were treated with Ce concentrations of 0, 4, 8, and 12 μM; after 5 d, germination percentage was recorded and after 10 d seedling growth was measured. For vegetative growth, a hydroponic system was established where 14-d-old plants without previous Ce treatment were transferred into nutrient solution. After two weeks of acclimatizing, 0, 25, 50, and 100 μM Ce were added to the nutrient solution for 28 d. Ce significantly increased germination and the initial growth variables of the seedlings. During vegetative growth, Ce increased plant height, number of tillers, root volume, and shoot fresh and dry biomass, without affecting root biomass weight. With low Ce concentrations (25 and 50 μM), the concentrations of chlorophylls and amino acids in the shoots were similar to those in the control, like amino acid concentration in the roots at a concentration of 25 μM Ce. Conversely, the concentration of total sugars increased in the shoot with the application of 25, 50, and 100 μM Ce, and in the roots with the application of 50 μM Ce. Also, Ce did not affect the concentration of macro or micronutrients in the shoots. However, in the roots, the high Ce concentration decreased the concentrations of Ca, Fe, Mn, and Zn, while the Mg concentration increased. Our results indicate that Ce, at the right concentrations, can function as a biostimulant in rice germination and growth. PMID:29579100

Medicago sativa--Sinorhizobium meliloti Symbiosis Promotes the Bioaccumulation of Zinc in Nodulated Roots.

PubMed

Zribi, Kais; Nouairi, Issam; Slama, Ines; Talbi-Zribi, Ons; Mhadhbi, Haythem

2015-01-01

In this study we investigated effects of Zn supply on germination, growth, inorganic solutes (Zn, Ca, Fe, and Mg) partitioning and nodulation of Medicago sativa This plant was cultivated with and without Zn (2 mM). Treatments were plants without (control) and with Zn tolerant strain (S532), Zn intolerant strain (S112) and 2 mM urea nitrogen fertilisation. Results showed that M. sativa germinates at rates of 50% at 2 mM Zn. For plants given nitrogen fertilisation, Zn increased plant biomass production. When grown with symbionts, Zn supply had no effect on nodulation. Moreover, plants with S112 showed a decrease of shoot and roots biomasses. However, in symbiosis with S532, an increase of roots biomass was observed. Plants in symbiosis with S. meliloti accumulated more Zn in their roots than nitrogen fertilised plants. Zn supply results in an increase of Ca concentration in roots of fertilised nitrogen plants. However, under Zn supply, Fe concentration decreased in roots and increased in nodules of plants with S112. Zn supply showed contrasting effects on Mg concentrations for plants with nitrogen fertilisation (increase) and plants with S112 (decrease). The capacity of M. sativa to accumulate Zn in their nodulated roots encouraged its use in phytostabilisation processes.

Preferential Association of Endophytic Bradyrhizobia with Different Rice Cultivars and Its Implications for Rice Endophyte Evolution

PubMed Central

Piromyou, Pongdet; Greetatorn, Teerana; Teamtisong, Kamonluck; Okubo, Takashi; Shinoda, Ryo; Nuntakij, Achara; Tittabutr, Panlada; Boonkerd, Nantakorn

2015-01-01

Plant colonization by bradyrhizobia is found not only in leguminous plants but also in nonleguminous species such as rice. To understand the evolution of the endophytic symbiosis of bradyrhizobia, the effect of the ecosystems of rice plantations on their associations was investigated. Samples were collected from various rice (Oryza sativa) tissues and crop rotational systems. The rice endophytic bradyrhizobia were isolated on the basis of oligotrophic properties, selective medium, and nodulation on siratro (Macroptilium atropurpureum). Six bradyrhizobial strains were obtained exclusively from rice grown in a crop rotational system. The isolates were separated into photosynthetic bradyrhizobia (PB) and nonphotosynthetic bradyrhizobia (non-PB). Thai bradyrhizobial strains promoted rice growth of Thai rice cultivars better than the Japanese bradyrhizobial strains. This implies that the rice cultivars possess characteristics that govern rice-bacterium associations. To examine whether leguminous plants in a rice plantation system support the persistence of rice endophytic bradyrhizobia, isolates were tested for legume nodulation. All PB strains formed symbioses with Aeschynomene indica and Aeschynomene evenia. On the other hand, non-PB strains were able to nodulate Aeschynomene americana, Vigna radiata, and M. atropurpureum but unable to nodulate either A. indica or A. evenia. Interestingly, the nodABC genes of all of these bradyrhizobial strains seem to exhibit low levels of similarity to those of Bradyrhizobium diazoefficiens USDA110 and Bradyrhizobium sp. strain ORS285. From these results, we discuss the evolution of the plant-bradyrhizobium association, including nonlegumes, in terms of photosynthetic lifestyle and nod-independent interactions. PMID:25710371

Long-term impact of sewage irrigation on soil properties and assessing risk in relation to transfer of metals to human food chain.

PubMed

Meena, Ramu; Datta, S P; Golui, Debasis; Dwivedi, B S; Meena, M C

2016-07-01

A case study was undertaken to assess the risk of sewage-irrigated soils in relation to the transfer of trace elements to rice and wheat grain. For this purpose, peri-urban agricultural lands under the Keshopur Effluent Irrigation Scheme (KEIS) of Delhi were selected. These agricultural lands have been receiving irrigation through sewage effluents since 1979. Sewage effluent, groundwater, soil, and plant (rice and wheat grain) samples were collected with GPS coordinates from this peri-urban area. Under wheat crop, sewage irrigation for four decades resulted into a significant buildup of zinc (141 %), copper (219 %), iron (514 %), nickel (75.0 %), and lead (28.1 %) in sewage-irrigated soils over adjacent tube well water-irrigated ones. Under rice crop, there was also a significant buildup of phosphorus (339 %), sulfur (130 %), zinc (287 %), copper (352 %), iron (457 %), nickel (258 %), lead (136 %), and cadmium (147 %) in sewage-irrigated soils as compared to that of tube well water-irrigated soils. The values of hazard quotient (HQ) for intake of trace toxic elements by humans through consumption of rice and wheat grain grown on these sewage-irrigated soils were well within the safe permissible limit. The variation in Zn, Ni, and Cd content in wheat grain could be explained by solubility-free ion activity model (FIAM) to the extent of 50.1, 56.8, and 37.2 %, respectively. Corresponding values for rice grain were 49.9, 41.2, and 42.7 %, respectively. As high as 36.4 % variation in As content in rice grain could be explained by solubility-FIAM model. Toxic limit of extractable Cd and As in soil for rice in relation to soil properties and human health hazard associated with consumption of rice grain by humans was established. A similar exercise was also done in respect of Cd for wheat. The conceptual framework of fixing the toxic limit of extractable metals and metalloid in soils with respect to soil properties and human health hazard under the modeling framework was established.

Effects of fertilization on crop production and nutrient-supplying capacity under rice-oilseed rape rotation system.

PubMed

Yousaf, Muhammad; Li, Jifu; Lu, Jianwei; Ren, Tao; Cong, Rihuan; Fahad, Shah; Li, Xiaokun

2017-04-28

Incredible accomplishments have been achieved in agricultural production in China, but many demanding challenges for ensuring food security and environmental sustainability remain. Field experiments were conducted from 2011-2013 at three different sites, including Honghu, Shayang, and Jingzhou in China, to determine the effects of fertilization on enhancing crop productivity and indigenous nutrient-supplying capacity (INuS) in a rice (Oryza sativa L.)-rapeseed (Brassica napus L.) rotation. Four mineral fertilizer treatments (NPK, NP, NK and PK) were applied in a randomized complete block design with three replicates. Crop yields were increased by 19-41% (rice) and 61-76% (rapeseed) during the two years of rice-rapeseed rotation under NPK fertilization compared to PK fertilization across the study sites. Yield responses to fertilization were ranked NPK > NP > NK > PK, illustrating that N deficiency was the most limiting condition in a rice-rapeseed rotation, followed by P and K deficiencies. The highest and lowest N, P and K accumulations were observed under NPK and PK fertilization, respectively. The INuS of the soil decreased to a significant extent and affected rice-rapeseed rotation productivity at each site under NP, NK, and PK fertilization when compared to NPK. Based on the study results, a balanced nutrient application using NPK fertilization is a key management strategy for enhancing rice-rapeseed productivity and environmental safety.

OsSUV3 transgenic rice maintains higher endogenous levels of plant hormones that mitigates adverse effects of salinity and sustains crop productivity.

PubMed

Sahoo, Ranjan Kumar; Ansari, Mohammad Wahid; Tuteja, Renu; Tuteja, Narendra

2014-01-01

The SUV3 (suppressor of Var 3) gene encodes a DNA and RNA helicase, which is localized in the mitochondria. Plant SUV3 has not yet been characterized in detail. However, the Arabidopsis ortholog of SUV3 (AT4G14790) has been shown to be involved in embryo sac development. Previously, we have reported that rice SUV3 functions as DNA and RNA helicase and provides salinity stress tolerance by maintaining photosynthesis and antioxidant machinery. Here, we report further analysis of the transgenic OsSUV3 rice plants under salt stress. The transgenic OsSUV3 overexpressing rice T1 lines showed significantly higher endogenous content of plant hormones viz., gibberellic acid (GA3), zeatin (Z) and indole-3-acetic acid (IAA) in leaf, stem and root as compared to wild-type (WT), vector control (VC) and antisense (AS) plants under salt (200 mM NaCl) stress condition. A similar trend of endogenous plant hormones profile was also reflected in the T2 generation of OsSUV3 transgenic rice under defined parameters and stress condition. In response to stress, OsSUV3 rice plants maintained plant hormone levels that regulate the expression of several stress-induced genes and reduce adverse effects of salt on plant growth and development and therefore sustains crop productivity.

Hormonal regulation of floret closure of rice (Oryza sativa)

PubMed Central

Huang, Youming; Zeng, Xiaochun

2018-01-01

Plant hormones play important roles in regulating every aspect of growth, development, and metabolism of plants. We are interested in understanding hormonal regulation of floret opening and closure in plants. This is a particularly important problem for hybrid rice because regulation of flowering time is vitally important in hybrid rice seed production. However, little was known about the effects of plant hormones on rice flowering. We have shown that jasmonate and methyl jasmonate play significant roles in promoting rice floret opening. In this study, we investigated the effects of auxins including indole-3-acidic acid (IAA), indole-3-butyric acid (IBA), 1-naphthalene-acetic acid (NAA), 2,4-dichlorophenoxy acetic acid (2,4-D) and 3,6-dichloro-2-methoxybenzoic acid (DIC) and abscisic acid (ABA) on floret closure of four fertile and three sterile varieties of rice. The results from field studies in three growing seasons in 2013–2015 showed that the percentages of closed florets were significantly lower in plants treated with IAA, IBA, 2,4-D, DIC and NAA and that the durations of floret opening were significantly longer in plants treated with the same auxins. The auxins exhibited time- and concentration-dependant effects on floret closure. ABA displayed opposite effects of auxins because it increased the percentages of floret closure and decreased the length of floret opening of rice varieties. The degree of auxin-inhibiting and ABA-promoting effects on floret closure was varied somewhat but not significantly different among the rice varieties. Endogenous IAA levels were the highest in florets collected shortly before opening followed by a sharp decline in florets with maximal angles of opening and a significant jump of IAA levels shortly after floret closure in both fertile and sterile rice plants. ABA levels showed an opposite trend in the same samples. Our results showed that auxins delayed but ABA promoted the closure of rice floret regardless of the varieties. PMID:29879200

Deciphering the factors associated with the colonization of rice plants by cyanobacteria.

PubMed

Bidyarani, Ngangom; Prasanna, Radha; Chawla, Gautam; Babu, Santosh; Singh, Rajendra

2015-04-01

Cyanobacteria-rice plant interactions were analyzed using a hydroponics experiment. The activity of plant defense and pathogenesis-related enzymes, scanning electron microscopy, growth, nitrogen fixation (measured as ARA), and DNA fingerprinting assays proved useful in illustrating the nature of associations of cyanobacteria with rice plants. Microscopic analyses revealed the presence of short filaments and coiled masses of filaments of cyanobacteria near the epidermis and cortex of roots and shoot tissues. Among the six cyanobacterial strains employed, Calothrix sp. (RPC1), Anabaena laxa (RPAN8), and Anabaena azollae (C16) were the best performing strains, in terms of colonization in roots and stem. These strains also enhanced nitrogen fixation and stimulated the activity of plant defense/cell wall-degrading enzymes. A significantly high correlation was also recorded between the elicited plant enzymes, growth, and ARA. DNA fingerprinting using highly iterated palindromic sequences (HIP-TG) further helped in proving the establishment of inoculated organisms in the roots/shoots of rice plants. This study illustrated that the colonization of cyanobacteria in the plant tissues is facilitated by increased elicitation of plant enzymes, leading to improved plant growth, nutrient mobilization, and enhanced plant fitness. Such strains can be promising candidates for developing "cyanobacteria colonized-nitrogen-fixing rice plants" in the future. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluating the non-rice host plant species of Sesamia inferens (Lepidoptera: Noctuidae) as natural refuges: resistance management of Bt rice.

PubMed

Liu, Zhuorong; Gao, Yulin; Luo, Ju; Lai, Fengxiang; Li, Yunhe; Fu, Qiang; Peng, Yufa

2011-06-01

Although rice (Oryza sativa L.) lines that express Bacillus thuringiensis (Bt) toxins have shown great potential for managing the major Lepidoptera pests of rice in southern China, including Sesamia inferens, their long-term use is dependent on managing resistance development to Bt toxins in pest populations. The maintenance of "natural" refuges, non-Bt expressing plants that are hosts for a target pest, has been proposed as a means to minimize the evolution of resistance to Bt toxins in transgenic plants. In the current study, field surveys and greenhouse experiments were conducted to identify host plants of S. inferens that could serve as "natural" refuges in rice growing areas of southern China. A field survey showed that 34 plant species in four families can be alternative host plants of S. inferens. Based on injury level under field conditions, rice (Oryza sativa L.); water oat (Zizania latifolia Griseb.); corn (Zea mays L.); tidalmarsh flatsedge (Cyperus serotinus Rottb.); and narrow-leaved cat-tail (Typha angustifolia Linn.) were identified as the primary host plant species of S. inferens. Greenhouse experiments further demonstrated that water oat, corn, and narrow-leaved cat-tail could support the survival and development of S. inferens. Interestingly, greenhouse experiments showed that S. inferens preferred to lay eggs on tidalmarsh flatsedge compared with the other three nonrice host species, although no pupae were found in the plants examined in field surveys. Few larvae were found to survive on tidalmarsh flatsedge in greenhouse bioassays, suggesting that tidalmarsh flatsedge could serve as a "dead-end" trap crop for S. inferens, but is not a candidate to serve as natural refuge to maintain susceptible S. inferens. Overall, these results suggest that water-oat, corn, and narrow-leaved cat-tail might serve as "natural refuge" for S. inferens in rice planting area of southern China when Bt rice varieties are planted.

From the concept of totipotency to biofortified cereals.

PubMed

Potrykus, Ingo

2015-01-01

I was a college teacher when opportunity opened a path into academia. A fascination with totipotency channeled me into research on tissue culture. As I was more interested in contributions to food security than in scientific novelty, I turned my attention to the development of genetic modification technology for cereals. From my cell culture experience, I had reasons not to trust Agrobacterium for that purpose, and I developed direct gene transfer instead. In the early 1990s, I became aware of the problem of micronutrient deficiency, particularly vitamin A deficiency in rice-eating populations. Golden Rice, which contains increased amounts of provitamin A, was probably instrumental for the concept of biofortification to take off. I realized that this rice would remain an academic exercise if product development and product registration were not addressed, and this is what I focused on after my retirement. Although progress is slowly being made, had I known what this pursuit would entail, perhaps I would not have started. Hopefully Golden Rice will reach the needy during my lifetime.

Relationships between starch synthase I and branching enzyme isozymes determined using double mutant rice lines

PubMed Central

2014-01-01

Background Starch is the most important carbohydrate in plant storage tissues. Multiple isozymes in at least four enzyme classes are involved in starch biosynthesis. Some of these isozymes are thought to interact and form complexes for efficient starch biosynthesis. Of these enzyme classes, starch synthases (SSs) and branching enzymes (BEs) play particularly central roles. Results We generated double mutant lines (ss1/be1 and ss1 L /be2b) between SSI (the largest component of total soluble SS activity) and BEI or BEIIb (major BEs in developing rice endosperm) to explore the relationships among these isozymes. The seed weight of ss1/be1 was comparable to that of wild type, although most ss1/be2b seeds were sterile and no double recessive plants were obtained. The seed weight of the double recessive mutant line ss1 L /be2b, derived from the leaky ss1 mutant (ss1 L ) and be2b, was higher than that of the single be2b mutant. Analyses of the chain-length distribution of amylopectin in ss1/be1 endosperm revealed additive effects of SSI and BEI on amylopectin structure. Chain-length analysis indicated that the BEIIb deficiency significantly reduced the ratio of short chains in amylopectin of ss1 L /be2b. The amylose content of endosperm starch of ss1/be1 and ss1 L /be2b was almost the same as that of wild type, whereas the endosperm starch of be2b contained more amylose than did that of wild type. SSI, BEI, and BEIIb deficiency also affected the extent of binding of other isozymes to starch granules. Conclusions Analysis of the chain-length distribution in amylopectin of the double mutant lines showed that SSI and BEI or BEIIb primarily function independently, and branching by BEIIb is followed by SSI chain elongation. The increased amylose content in be2b was because of reduced amylopectin biosynthesis; however, the lower SSI activity in this background may have enhanced amylopectin biosynthesis as a result of a correction of imbalance between the branching and elongation found in the single mutant. The fact that a deficiency of SSI, BEI, or BEIIb affected the affinity of other starch biosynthetic isozymes for the starch granule implies that there is a close interaction among SSI, BEI and BEIIb during amylopectin biosynthesis in rice endosperm. PMID:24670252

Relationships between starch synthase I and branching enzyme isozymes determined using double mutant rice lines.

PubMed

Abe, Natsuko; Asai, Hiroki; Yago, Hikari; Oitome, Naoko F; Itoh, Rumiko; Crofts, Naoko; Nakamura, Yasunori; Fujita, Naoko

2014-03-26

Starch is the most important carbohydrate in plant storage tissues. Multiple isozymes in at least four enzyme classes are involved in starch biosynthesis. Some of these isozymes are thought to interact and form complexes for efficient starch biosynthesis. Of these enzyme classes, starch synthases (SSs) and branching enzymes (BEs) play particularly central roles. We generated double mutant lines (ss1/be1 and ss1L/be2b) between SSI (the largest component of total soluble SS activity) and BEI or BEIIb (major BEs in developing rice endosperm) to explore the relationships among these isozymes. The seed weight of ss1/be1 was comparable to that of wild type, although most ss1/be2b seeds were sterile and no double recessive plants were obtained. The seed weight of the double recessive mutant line ss1L/be2b, derived from the leaky ss1 mutant (ss1L) and be2b, was higher than that of the single be2b mutant. Analyses of the chain-length distribution of amylopectin in ss1/be1 endosperm revealed additive effects of SSI and BEI on amylopectin structure. Chain-length analysis indicated that the BEIIb deficiency significantly reduced the ratio of short chains in amylopectin of ss1L/be2b. The amylose content of endosperm starch of ss1/be1 and ss1L/be2b was almost the same as that of wild type, whereas the endosperm starch of be2b contained more amylose than did that of wild type. SSI, BEI, and BEIIb deficiency also affected the extent of binding of other isozymes to starch granules. Analysis of the chain-length distribution in amylopectin of the double mutant lines showed that SSI and BEI or BEIIb primarily function independently, and branching by BEIIb is followed by SSI chain elongation. The increased amylose content in be2b was because of reduced amylopectin biosynthesis; however, the lower SSI activity in this background may have enhanced amylopectin biosynthesis as a result of a correction of imbalance between the branching and elongation found in the single mutant. The fact that a deficiency of SSI, BEI, or BEIIb affected the affinity of other starch biosynthetic isozymes for the starch granule implies that there is a close interaction among SSI, BEI and BEIIb during amylopectin biosynthesis in rice endosperm.

Transgenic rice expressing a codon-modified synthetic CP4-EPSPS confers tolerance to broad-spectrum herbicide, glyphosate.

PubMed

Chhapekar, Sushil; Raghavendrarao, Sanagala; Pavan, Gadamchetty; Ramakrishna, Chopperla; Singh, Vivek Kumar; Phanindra, Mullapudi Lakshmi Venkata; Dhandapani, Gurusamy; Sreevathsa, Rohini; Ananda Kumar, Polumetla

2015-05-01

Highly tolerant herbicide-resistant transgenic rice was developed by expressing codon-modified synthetic CP4--EPSPS. The transformants could tolerate up to 1% commercial glyphosate and has the potential to be used for DSR (direct-seeded rice). Weed infestation is one of the major biotic stress factors that is responsible for yield loss in direct-seeded rice (DSR). Herbicide-resistant rice has potential to improve the efficiency of weed management under DSR. Hence, the popular indica rice cultivar IR64, was genetically modified using Agrobacterium-mediated transformation with a codon-optimized CP4-EPSPS (5-enolpyruvylshikimate-3-phosphate synthase) gene, with N-terminal chloroplast targeting peptide from Petunia hybrida. Integration of the transgenes in the selected rice plants was confirmed by Southern hybridization and expression by Northern and herbicide tolerance assays. Transgenic plants showed EPSPS enzyme activity even at high concentrations of glyphosate, compared to untransformed control plants. T0, T1 and T2 lines were tested by herbicide bioassay and it was confirmed that the transgenic rice could tolerate up to 1% of commercial Roundup, which is five times more in dose used to kill weeds under field condition. All together, the transgenic rice plants developed in the present study could be used efficiently to overcome weed menace.

Observations on the fulvous tree duck in Louisiana

USGS Publications Warehouse

Meanley, B.; Meanley, A.G.

1959-01-01

The Fulvous Tree Duck is a locally common breeding bird of the rice fields of southwestern Louisiana. Observations made in 1955, 1956 and 1957, showed that this species was probably most abundant in the vicinity of Mamou, Evangeline Parish, and Roanoke, Jefferson Davis Parish. Tree ducks arrive in the rice country as the rice is planted in the spring and usually depart following fall harvest. A few winter in the coastal marshes. The nesting period extends from late May well into August. Thirteen and 20 pairs were found nesting in two separate five-square-mile areas. All nests observed were in rice fields. Clutch size in several nests found by John J. Lynch averaged about 13 eggs. A clutch of 23 eggs was probably a dump nest. Several investigators have reported incubation periods varying from 24 to 26 days. Nests were constructed of rice or other plants that occurred in the rice fields; they usually had a canopy and ramp; none was lined with down. Renesting compensated for some first attempt losses. Depredations on rice plantings sometimes occurred in spring in water-planted rice fields. Favorite foods were seeds of grasses and sedges found in rice fields. Flocks totalling 3000 were occasionally seen in the fall on the Lacassine Wildlife Refuge.

Microarray Meta-Analysis Focused on the Response of Genes Involved in Redox Homeostasis to Diverse Abiotic Stresses in Rice

PubMed Central

de Abreu Neto, Joao B.; Frei, Michael

2016-01-01

Plants are exposed to a wide range of abiotic stresses (AS), which often occur in combination. Because physiological investigations typically focus on one stress, our understanding of unspecific stress responses remains limited. The plant redox homeostasis, i.e., the production and removal of reactive oxygen species (ROS), may be involved in many environmental stress conditions. Therefore, this study intended to identify genes, which are activated in diverse AS, focusing on ROS-related pathways. We conducted a meta-analysis (MA) of microarray experiments, focusing on rice. Transcriptome data were mined from public databases and fellow researchers, which represented 36 different experiments and investigated diverse AS, including ozone stress, drought, heat, cold, salinity, and mineral deficiencies/toxicities. To overcome the inherent artifacts of different MA methods, data were processed using Fisher, rOP, REM, and product of rank (GeneSelector), and genes identified by most approaches were considered as shared differentially expressed genes (DEGs). Two MA strategies were adopted: first, datasets were separated into shoot, root, and seedling experiments, and these tissues were analyzed separately to identify shared DEGs. Second, shoot and seedling experiments were classed into oxidative stress (OS), i.e., ozone and hydrogen peroxide treatments directly producing ROS in plant tissue, and other AS, in which ROS production is indirect. In all tissues and stress conditions, genes a priori considered as ROS-related were overrepresented among the DEGs, as they represented 4% of all expressed genes but 7–10% of the DEGs. The combined MA approach was substantially more conservative than individual MA methods and identified 1001 shared DEGs in shoots, 837 shared DEGs in root, and 1172 shared DEGs in seedlings. Within the OS and AS groups, 990 and 1727 shared DEGs were identified, respectively. In total, 311 genes were shared between OS and AS, including many regulatory genes. Combined co-expression analysis identified among those a cluster of 42 genes, many involved in the photosynthetic apparatus and responsive to drought, iron deficiency, arsenic toxicity, and ozone. Our data demonstrate the importance of redox homeostasis in plant stress responses and the power of MA to identify candidate genes underlying unspecific signaling pathways. PMID:26793229

Do rice water weevils and rice stem borers compete when sharing a host plant?*

PubMed Central

Shi, Sheng-wei; He, Yan; Ji, Xiang-hua; Jiang, Ming-xing; Cheng, Jia-an

2008-01-01

The rice water weevil (RWW) Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae) is an invasive insect pest of rice Oryza sativa L. in China. Little is known about the interactions of this weevil with indigenous herbivores. In the present study, adult feeding and population density of the weevil, injury level of striped stem borer Chilo suppressalis (Walker) (Lepidoptera: Pyralidae) and pink stem borer Sesamia inferens (Walker) (Lepidoptera: Noctuidae) to rice, as well as growth status of their host plants were surveyed in a rice field located in Southeastern Zhejiang, China, in 2004 with the objective to discover interspecific interactions on the rice. At tillering stage, both adult feeding of the weevil and injury of the stem borers tended to occur on larger tillers (bearing 5 leaves) compared with small tillers (bearing 2~4 leaves), but the insects showed no evident competition with each other. At booting stage, the stem borers caused more withering/dead hearts and the weevil reached a higher density on the plants which had more productive tillers and larger root system; the number of weevils per tiller correlated negatively with the percentage of withering/dead hearts of plants in a hill. These observations indicate that interspecific interactions exist between the rice water weevil and the rice stem borers with negative relations occurring at booting or earlier developmental stages of rice. PMID:18600788

Do rice water weevils and rice stem borers compete when sharing a host plant?

PubMed

Shi, Sheng-Wei; He, Yan; Ji, Xiang-Hua; Jiang, Ming-Xing; Cheng, Jia-An

2008-07-01

The rice water weevil (RWW) Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae) is an invasive insect pest of rice Oryza sativa L. in China. Little is known about the interactions of this weevil with indigenous herbivores. In the present study, adult feeding and population density of the weevil, injury level of striped stem borer Chilo suppressalis (Walker) (Lepidoptera: Pyralidae) and pink stem borer Sesamia inferens (Walker) (Lepidoptera: Noctuidae) to rice, as well as growth status of their host plants were surveyed in a rice field located in Southeastern Zhejiang, China, in 2004 with the objective to discover interspecific interactions on the rice. At tillering stage, both adult feeding of the weevil and injury of the stem borers tended to occur on larger tillers (bearing 5 leaves) compared with small tillers (bearing 2~4 leaves), but the insects showed no evident competition with each other. At booting stage, the stem borers caused more withering/dead hearts and the weevil reached a higher density on the plants which had more productive tillers and larger root system; the number of weevils per tiller correlated negatively with the percentage of withering/dead hearts of plants in a hill. These observations indicate that interspecific interactions exist between the rice water weevil and the rice stem borers with negative relations occurring at booting or earlier developmental stages of rice.

Understanding the molecular basis of plant growth promotional effect of Pseudomonas fluorescens on rice through protein profiling

PubMed Central

2009-01-01

Background Plant Growth Promoting Rhizobacteria (PGPR), Pseudomonas fluorescens strain KH-1 was found to exhibit plant growth promotional activity in rice under both in-vitro and in-vivo conditions. But the mechanism underlying such promotional activity of P. fluorescens is not yet understood clearly. In this study, efforts were made to elucidate the molecular responses of rice plants to P. fluorescens treatment through protein profiling. Two-dimensional polyacrylamide gel electrophoresis strategy was adopted to identify the PGPR responsive proteins and the differentially expressed proteins were analyzed by mass spectrometry. Results Priming of P. fluorescens, 23 different proteins found to be differentially expressed in rice leaf sheaths and MS analysis revealed the differential expression of some important proteins namely putative p23 co-chaperone, Thioredoxin h- rice, Ribulose-bisphosphate carboxylase large chain precursor, Nucleotide diPhosphate kinase, Proteosome sub unit protein and putative glutathione S-transferase protein. Conclusion Functional analyses of the differential proteins were reported to be directly or indirectly involved in growth promotion in plants. Thus, this study confirms the primary role of PGPR strain KH-1 in rice plant growth promotion. PMID:20034395

Rice ethylene-response AP2/ERF factor OsEATB restricts internode elongation by down-regulating a gibberellin biosynthetic gene.

PubMed

Qi, Weiwei; Sun, Fan; Wang, Qianjie; Chen, Mingluan; Huang, Yunqing; Feng, Yu-Qi; Luo, Xiaojin; Yang, Jinshui

2011-09-01

Plant height is a decisive factor in plant architecture. Rice (Oryza sativa) plants have the potential for rapid internodal elongation, which determines plant height. A large body of physiological research has shown that ethylene and gibberellin are involved in this process. The APETALA2 (AP2)/Ethylene-Responsive Element Binding Factor (ERF) family of transcriptional factors is only present in the plant kingdom. This family has various developmental and physiological functions. A rice AP2/ERF gene, OsEATB (for ERF protein associated with tillering and panicle branching) was cloned from indica rice variety 9311. Bioinformatic analysis suggested that this ERF has a potential new function. Ectopic expression of OsEATB showed that the cross talk between ethylene and gibberellin, which is mediated by OsEATB, might underlie differences in rice internode elongation. Analyses of gene expression demonstrated that OsEATB restricts ethylene-induced enhancement of gibberellin responsiveness during the internode elongation process by down-regulating the gibberellin biosynthetic gene, ent-kaurene synthase A. Plant height is negatively correlated with tiller number, and higher yields are typically obtained from dwarf crops. OsEATB reduces rice plant height and panicle length at maturity, promoting the branching potential of both tillers and spikelets. These are useful traits for breeding high-yielding crops.

Mapping paddy rice planting area in rice-wetland coexistent areas through analysis of Landsat 8 OLI and MODIS images

PubMed Central

Zhou, Yuting; Xiao, Xiangming; Qin, Yuanwei; Dong, Jinwei; Zhang, Geli; Kou, Weili; Jin, Cui; Wang, Jie; Li, Xiangping

2016-01-01

Accurate and up-to-date information on the spatial distribution of paddy rice fields is necessary for the studies of trace gas emissions, water source management, and food security. The phenology-based paddy rice mapping algorithm, which identifies the unique flooding stage of paddy rice, has been widely used. However, identification and mapping of paddy rice in rice-wetland coexistent areas is still a challenging task. In this study, we found that the flooding/transplanting periods of paddy rice and natural wetlands were different. The natural wetlands flood earlier and have a shorter duration than paddy rice in the Panjin Plain, a temperate region in China. We used this asynchronous flooding stage to extract the paddy rice planting area from the rice-wetland coexistent area. MODIS Land Surface Temperature (LST) data was used to derive the temperature-defined plant growing season. Landsat 8 OLI imagery was used to detect the flooding signal and then paddy rice was extracted using the difference in flooding stages between paddy rice and natural wetlands. The resultant paddy rice map was evaluated with in-situ ground-truth data and Google Earth images. The estimated overall accuracy and Kappa coefficient were 95% and 0.90, respectively. The spatial pattern of OLI-derived paddy rice map agrees well with the paddy rice layer from the National Land Cover Dataset from 2010 (NLCD-2010). The differences between RiceLandsat and RiceNLCD are in the range of ±20% for most 1-km grid cell. The results of this study demonstrate the potential of the phenology-based paddy rice mapping algorithm, via integrating MODIS and Landsat 8 OLI images, to map paddy rice fields in complex landscapes of paddy rice and natural wetland in the temperate region. PMID:27688742

Mapping paddy rice planting area in rice-wetland coexistent areas through analysis of Landsat 8 OLI and MODIS images.

PubMed

Zhou, Yuting; Xiao, Xiangming; Qin, Yuanwei; Dong, Jinwei; Zhang, Geli; Kou, Weili; Jin, Cui; Wang, Jie; Li, Xiangping

2016-04-01

Accurate and up-to-date information on the spatial distribution of paddy rice fields is necessary for the studies of trace gas emissions, water source management, and food security. The phenology-based paddy rice mapping algorithm, which identifies the unique flooding stage of paddy rice, has been widely used. However, identification and mapping of paddy rice in rice-wetland coexistent areas is still a challenging task. In this study, we found that the flooding/transplanting periods of paddy rice and natural wetlands were different. The natural wetlands flood earlier and have a shorter duration than paddy rice in the Panjin Plain, a temperate region in China. We used this asynchronous flooding stage to extract the paddy rice planting area from the rice-wetland coexistent area. MODIS Land Surface Temperature (LST) data was used to derive the temperature-defined plant growing season. Landsat 8 OLI imagery was used to detect the flooding signal and then paddy rice was extracted using the difference in flooding stages between paddy rice and natural wetlands. The resultant paddy rice map was evaluated with in-situ ground-truth data and Google Earth images. The estimated overall accuracy and Kappa coefficient were 95% and 0.90, respectively. The spatial pattern of OLI-derived paddy rice map agrees well with the paddy rice layer from the National Land Cover Dataset from 2010 (NLCD-2010). The differences between Rice Landsat and Rice NLCD are in the range of ±20% for most 1-km grid cell. The results of this study demonstrate the potential of the phenology-based paddy rice mapping algorithm, via integrating MODIS and Landsat 8 OLI images, to map paddy rice fields in complex landscapes of paddy rice and natural wetland in the temperate region.

Effects of the magnetic resonance imaging contrast agent Gd-DTPA on plant growth and root imaging in rice.

PubMed

Liu, Zan; Qian, Junchao; Liu, Binmei; Wang, Qi; Ni, Xiaoyu; Dong, Yaling; Zhong, Kai; Wu, Yuejin

2014-01-01

Although paramagnetic contrast agents have a wide range of applications in medical studies involving magnetic resonance imaging (MRI), these agents are seldom used to enhance MRI images of plant root systems. To extend the application of MRI contrast agents to plant research and to develop related techniques to study root systems, we examined the applicability of the MRI contrast agent Gd-DTPA to the imaging of rice roots. Specifically, we examined the biological effects of various concentrations of Gd-DTPA on rice growth and MRI images. Analysis of electrical conductivity and plant height demonstrated that 5 mmol Gd-DTPA had little impact on rice in the short-term. The results of signal intensity and spin-lattice relaxation time (T1) analysis suggested that 5 mmol Gd-DTPA was the appropriate concentration for enhancing MRI signals. In addition, examination of the long-term effects of Gd-DTPA on plant height showed that levels of this compound up to 5 mmol had little impact on rice growth and (to some extent) increased the biomass of rice.

Can herbicide safeners allow selective control of weedy rice infesting rice crops?

PubMed

Busi, Roberto; Nguyen, Nghia K; Chauhan, Bhagirath S; Vidotto, Francesco; Tabacchi, Maurizio; Powles, Stephen B

2017-01-01

Rice is a major field crop of paramount importance for global food security. However, the increased adoption of more profitable and resource-efficient direct-seeded rice (DSR) systems has contributed to greater weed infestations, including weedy rice, which has become a severe problem in several Asian regions. In this study we have developed a conceptually novel method to protect rice plants at high doses of clomazone and triallate. The insecticide phorate applied to rice seeds provided a substantial level of protection against the herbicides clomazone or triallate. A quantity of 15 kg phorate ha -1 significantly increased the LD 50 values, which were more than twofold greater than for rice plants treated only with clomazone. A quantity of 20 kg phorate ha -1 in combination with 2000 g triallate ha -1 safened rice plants (80% survival) with LD 50 >3.4-fold greater than in phorate-untreated rice. Weed control efficacy was not lowered by the presence of phorate-treated rice seeds. Weedy rice is one of the most damaging global weeds and a major threat to DSR systems. In this study we have developed a proof-of-concept method to allow selective weedy rice control in rice crops. We call for herbicide discovery programmes and research to identify candidate safener and herbicide combinations to achieve selective herbicide control of weedy rice and alleviate weed infestations in global rice crops. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Changes in heavy metal bioavailability and speciation from a Pb-Zn mining soil amended with biochars from co-pyrolysis of rice straw and swine manure.

PubMed

Meng, Jun; Tao, Mengming; Wang, Lili; Liu, Xingmei; Xu, Jianming

2018-08-15

Biochar has been utilized as a good amendment to immobilize heavy metals in contaminated soils. However, the effectiveness of biochar in metal immobilization depends on biochar properties and metal species. In this study, the biochars produced from co-pyrolysis of rice straw with swine manure at 400°C were investigated to evaluate their effects on bioavailability and chemical speciation of four heavy metals (Cd, Cu, Pb and Zn) in a Pb-Zn contaminated soil through incubation experiment. Results showed that co-pyrolysis process significantly change the yield, ash content, pH, and electrical conductivity (EC) of the blended biochars compared with the single straw/manure biochar. The addition of these biochars significantly increased the soil pH, EC, and dissolved organic carbon (DOC) concentrations. The addition of biochars at a rate of 3% significantly reduced the CaCl 2 -extractable metal concentrations in the order of Pb>Cu>Zn>Cd. The exchangeable heavy metals decreased in all the biochar-amended soils whereas the carbonate-bound metal speciation increased. The increase in soil pH and the decrease in the CaCl 2 extractable metals indicated that these amendments can directly transform the highly availability metal speciation to the stable speciation in soils. In conclusion, biochar derived from co-pyrolysis of rice straw with swine manure at a mass ratio of 3:1 could most effectively immobilize the heavy metals in the soil. Copyright © 2018 Elsevier B.V. All rights reserved.

Identification and functional expression of ZIP1 transporter protein in Triticum dicoccoides

USDA-ARS?s Scientific Manuscript database

Zinc (Zn) deficiency is a common problem, especially in cereal-growing areas, leading to severe decreases in grain yield and nutritional quality. Among the cereal species, durum wheat is the most sensitive crop to Zn deficiency. One major reason for this high sensitivity of durum wheat is its poor ...

Molecular dynamics of detoxification and toxin-tolerance genes in brown planthopper (Nilaparvata lugens Stål., Homoptera: Delphacidae) feeding on resistant rice plants.

PubMed

Yang, Zhifan; Zhang, Futie; He, Qing; He, Guangcun

2005-06-01

To investigate the molecular response of brown planthopper, Nilaparvata lugens (BPH) to BPH-resistant rice plants, we isolated cDNA fragments of the genes encoding for carboxylesterase (CAR), trypsin (TRY), cytochrome P450 monooxygenase (P450), NADH-quinone oxidoreductase (NQO), acetylcholinesterase (ACE), and Glutathione S-transferase (GST). Expression profiles of the genes were monitored on fourth instar nymphs feeding on rice varieties with different resistance levels. Northern blot hybridization showed that, compared with BPH reared on susceptible rice TN1, expression of the genes for P450 and CAR was apparently up-regulated and TRY mRNA decreased in BPH feeding on a highly resistant rice line B5 and a moderately resistant rice variety MH63, respectively. Two transcripts of GST increased in BPH feeding on B5; but in BPH feeding on MH63, this gene was inducible and its expression reached a maximum level at 24 h, and then decreased slightly. The expression of NQO gene was enhanced in BPH on B5 plants but showed a constant expression in BPH on MH63 plants. No difference in ACE gene expression among BPH on different rice plants was detected by the RT-PCR method. The results suggest these genes may play important roles in the defense response of BPH to resistant rice.

Zinc is an essential trace element for spermatogenesis.

PubMed

Yamaguchi, Sonoko; Miura, Chiemi; Kikuchi, Kazuya; Celino, Fritzie T; Agusa, Tetsuro; Tanabe, Shinsuke; Miura, Takeshi

2009-06-30

Zinc (Zn) plays important roles in various biological activities but there is little available information regarding its functions in spermatogenesis. In our current study, we further examined the role of Zn during spermatogenesis in the Japanese eel (Anguilla japonica). Human CG (hCG) was injected into the animals to induce spermatogenesis, after which the concentration of Zn in the testis increased in tandem with the progression of spermatogenesis. Staining of testicular cells with a Zn-specific fluorescent probe revealed that Zn accumulates in germ cells, particularly in the mitochondria of spermatogonia and spermatozoa. Using an in vitro testicular organ culture system for the Japanese eel, production of a Zn deficiency by chelation with N,N,N',N'-tetrakis (2-pyridylemethyl)ethylenediamine (TPEN) caused apoptosis of the germ cells. However, this cell death was rescued by the addition of Zn to the cultures. Furthermore, an induced deficiency of Zn by TPEN chelation was found to inhibit the germ cell proliferation induced by 11-ketotestosterone (KT), a fish specific androgen, 17alpha,20beta-dihydroxy-4-pregnen-3-one (DHP), the initiator of meiosis in fish, and estradiol-17beta (E2), an inducer of spermatogonial stem-cell renewal. We also investigated the effects of Zn deficiency on sperm motility and observed that TPEN treatment of eel sperm suppressed the rate and duration of their motility but that co-treatment with Zn blocked the effects of TPEN. Our present results thus suggest that Zn is an essential trace element for the maintenance of germ cells, the progression spermatogenesis, and the regulation of sperm motility.

Agronomic Approach of Zinc Biofortification Can Increase Zinc Bioavailability in Wheat Flour and thereby Reduce Zinc Deficiency in Humans

PubMed Central

Liu, Dunyi; Liu, Yumin; Zhang, Wei; Chen, Xinping; Zou, Chunqin

2017-01-01

Zinc (Zn) deficiency is a common disorder of humans in developing countries. The effect of Zn biofortification (via application of six rates of Zn fertilizer to soil) on Zn bioavailability in wheat grain and flour and its impacts on human health was evaluated. Zn bioavailability was estimated with a trivariate model that included Zn homeostasis in the human intestine. As the rate of Zn fertilization increased, the Zn concentration increased in all flour fractions, but the percentages of Zn in standard flour (25%) and bran (75%) relative to total grain Zn were constant. Phytic acid (PA) concentrations in grain and flours were unaffected by Zn biofortification. Zn bioavailability and the health impact, as indicated by disability-adjusted life years (DALYs) saved, increased with the Zn application rate and were greater in standard and refined flour than in whole grain and coarse flour. The biofortified standard and refined flour obtained with application of 50 kg/ha ZnSO4·7H2O met the health requirement (3 mg of Zn obtained from 300 g of wheat flour) and reduced DALYs by >20%. Although Zn biofortification increased Zn bioavailability in standard and refined flour, it did not reduce the bioavailability of iron, manganese, or copper in wheat flour. PMID:28481273

Agronomic Approach of Zinc Biofortification Can Increase Zinc Bioavailability in Wheat Flour and thereby Reduce Zinc Deficiency in Humans.

PubMed

Liu, Dunyi; Liu, Yumin; Zhang, Wei; Chen, Xinping; Zou, Chunqin

2017-05-06

Zinc (Zn) deficiency is a common disorder of humans in developing countries. The effect of Zn biofortification (via application of six rates of Zn fertilizer to soil) on Zn bioavailability in wheat grain and flour and its impacts on human health was evaluated. Zn bioavailability was estimated with a trivariate model that included Zn homeostasis in the human intestine. As the rate of Zn fertilization increased, the Zn concentration increased in all flour fractions, but the percentages of Zn in standard flour (25%) and bran (75%) relative to total grain Zn were constant. Phytic acid (PA) concentrations in grain and flours were unaffected by Zn biofortification. Zn bioavailability and the health impact, as indicated by disability-adjusted life years (DALYs) saved, increased with the Zn application rate and were greater in standard and refined flour than in whole grain and coarse flour. The biofortified standard and refined flour obtained with application of 50 kg/ha ZnSO₄·7H₂O met the health requirement (3 mg of Zn obtained from 300 g of wheat flour) and reduced DALYs by >20%. Although Zn biofortification increased Zn bioavailability in standard and refined flour, it did not reduce the bioavailability of iron, manganese, or copper in wheat flour.

Green tissue-specific co-expression of chitinase and oxalate oxidase 4 genes in rice for enhanced resistance against sheath blight.

PubMed

Karmakar, Subhasis; Molla, Kutubuddin Ali; Chanda, Palas K; Sarkar, Sailendra Nath; Datta, Swapan K; Datta, Karabi

2016-01-01

Green tissue-specific simultaneous overexpression of two defense-related genes ( OsCHI11 & OsOXO4 ) in rice leads to significant resistance against sheath blight pathogen ( R. solani ) without distressing any agronomically important traits. Overexpressing two defense-related genes (OsOXO4 and OsCHI11) cloned from rice is effective at enhancing resistance against sheath blight caused by Rhizoctonia solani. These genes were expressed under the control of two different green tissue-specific promoters, viz. maize phosphoenolpyruvate carboxylase gene promoter, PEPC, and rice cis-acting 544-bp DNA element, immediately upstream of the D54O translational start site, P D54O-544 . Putative T0 transgenic rice plants were screened by PCR and integration of genes was confirmed by Southern hybridization of progeny (T1) rice plants. Successful expression of OsOXO4 and OsCHI11 in all tested plants was confirmed. Expression of PR genes increased significantly following pathogen infection in overexpressing transgenic plants. Following infection, transgenic plants exhibited elevated hydrogen peroxide levels, significant changes in activity of ROS scavenging enzymes and reduced membrane damage when compared to their wild-type counterpart. In a Rhizoctonia solani toxin assay, a detached leaf inoculation test and an in vivo plant bioassay, transgenic plants showed a significant reduction in disease symptoms in comparison to non-transgenic control plants. This is the first report of overexpression of two different PR genes driven by two green tissue-specific promoters providing enhanced sheath blight resistance in transgenic rice.

Interactive Effects of Southern Rice Black-Streaked Dwarf Virus Infection of Host Plant and Vector on Performance of the Vector, Sogatella furcifera (Homoptera: Delphacidae).

PubMed

Lei, Wenbin; Liu, Danfeng; Li, Pei; Hou, Maolin

2014-10-01

Performance of insect vectors can be influenced by the viruses they transmit, either directly by infection of the vectors or indirectly via infection of the host plants. Southern rice black-streaked dwarf virus (SRBSDV) is a propagative virus transmitted by the white-backed planthopper, Sogatella furcifera (Hovath). To elucidate the influence of SRBSDV on the performance of white-backed planthopper, life parameters of viruliferous and nonviruliferous white-backed planthopper fed rice seedlings infected or noninfected with SRBSDV were measured using a factorial design. Regardless of the infection status of the rice plant host, viruliferous white-backed planthopper nymphs took longer to develop from nymph to adult than did nonviruliferous nymphs. Viruliferous white-backed planthopper females deposited fewer eggs than nonviruliferous females and both viruliferous and nonviruliferous white-backed planthopper females laid fewer eggs on infected than on noninfected plants. Longevity of white-backed planthopper females was also affected by the infection status of the rice plant and white-backed planthopper. Nonviruliferous white-backed planthopper females that fed on infected rice plants lived longer than the other three treatment groups. These results indicate that the performance of white-backed planthopper is affected by SRBSDV either directly (by infection of white-backed planthopper) or indirectly (by infection of rice plant). The extended development of viruliferous nymphs and the prolonged life span of nonviruliferous adults on infected plants may increase their likelihood of transmitting virus, which would increase virus spread. © 2014 Entomological Society of America.

Identification of Morphological Character and Esterase Isozyme Pattern in Second-Generation Black Rice Plant Irradiated to Gamma Rays

NASA Astrophysics Data System (ADS)

Hartanti, R. S.; Putri, T. A. N.; Zulfa, F.; Sutarno; Suranto

2017-04-01

Black rice is one of the functional foods due to its high anthocyanin content. Black rice grain was irradiated by gamma rays with a dose of 200 Gy and 300 Gy. The main purpose of this irradiation is to induce mutation to the black rice plant in order to achieve the improved organism. This study was undertaken to elucidate the morphological character and esterase isozyme pattern of black rice plant after irradiated by gamma rays. There were morphological differences on leaves, stems and grains between irradiated and non irradiated black rice plant. Gamma radiation dose of 200 Gy showed the significant influence of the length of the stem, number of internodes, and length of leaves. The radiation dose of 300 Gy showed the significant influence of the decrease value of diameter of 3rd internodes, number of branches and width of leaves. Flowering time is getting faster as increasing radiation dose. At the age of 74 days after planting there are 9.15% plants of 200 Gy radiation dose that have flowered faster than normal plants. This value increased into 11.45% at the dose of radiation 300 Gy. There were differences in the esterase banding pattern between radiation dose of 200 Gy and 300 Gy than the control plants, indicated that randomly mutation has occurred.

Defense Responses in Rice Induced by Silicon Amendment against Infestation by the Leaf Folder Cnaphalocrocis medinalis

PubMed Central

Han, Yongqiang; Li, Pei; Gong, Shaolong; Yang, Lang; Wen, Lizhang; Hou, Maolin

2016-01-01

Silicon (Si) amendment to plants can confer enhanced resistance to herbivores. In the present study, the physiological and cytological mechanisms underlying the enhanced resistance of plants with Si addition were investigated for one of the most destructive rice pests in Asian countries, the rice leaf folder, Cnaphalocrocis medinalis (Guenée). Activities of defense-related enzymes, superoxide dismutase, peroxidase, catalase, phenylalanine ammonia-lyase, and polyphenol oxidase, and concentrations of malondialdehyde and soluble protein in leaves were measured in rice plants with or without leaf folder infestation and with or without Si amendment at 0.32 g Si/kg soil. Silicon amendment significantly reduced leaf folder larval survival. Silicon addition alone did not change activities of defense-related enzymes and malondialdehyde concentration in rice leaves. With leaf folder infestation, activities of the defense-related enzymes increased and malondialdehyde concentration decreased in plants amended with Si. Soluble protein content increased with Si addition when the plants were not infested, but was reduced more in the infested plants with Si amendment than in those without Si addition. Regardless of leaf folder infestation, Si amendment significantly increased leaf Si content through increases in the number and width of silica cells. Our results show that Si addition enhances rice resistance to the leaf folder through priming the feeding stress defense system, reduction in soluble protein content and cell silicification of rice leaves. PMID:27124300

Virus altered rice attractiveness to planthoppers is mediated by volatiles and related to virus titre and expression of defence and volatile-biosynthesis genes.

PubMed

Lu, Guanghua; Zhang, Tong; He, Yuange; Zhou, Guohui

2016-12-07

Viruses may induce changes in plant hosts and vectors to enhance their transmission. The white-backed planthopper (WBPH) and brown planthopper (BPH) are vectors of Southern rice black-streaked dwarf virus (SRBSDV) and Rice ragged stunt virus (RRSV), respectively, which cause serious rice diseases. We herein describe the effects of SRBSDV and RRSV infections on host-selection behaviour of vector and non-vector planthoppers at different disease stages. The Y-tube olfactometer choice and free-choice tests indicated that SRBSDV and RRSV infections altered the attractiveness of rice plants to vector and non-vector planthoppers. The attractiveness was mainly mediated by rice volatiles, and varied with disease progression. The attractiveness of the SRBSDV- or RRSV-infected rice plants to the virus-free WBPHs or BPHs initially decreased, then increased, and finally decreased again. For the viruliferous WBPHs and BPHs, SRBSDV or RRSV infection increased the attractiveness of plants more for the non-vector than for the vector planthoppers. Furthermore, we observed that the attractiveness of infected plants to planthoppers was positively correlated with the virus titres. The titre effects were greater for virus-free than for viruliferous planthoppers. Down-regulated defence genes OsAOS1, OsICS, and OsACS2 and up-regulated volatile-biosynthesis genes OsLIS, OsCAS, and OsHPL3 expression in infected plants may influence their attractiveness.

Suppression of the rice fatty-acid desaturase gene OsSSI2 enhances resistance to blast and leaf blight diseases in rice.

PubMed

Jiang, Chang-Jie; Shimono, Masaki; Maeda, Satoru; Inoue, Haruhiko; Mori, Masaki; Hasegawa, Morifumi; Sugano, Shoji; Takatsuji, Hiroshi

2009-07-01

Fatty acids and their derivatives play important signaling roles in plant defense responses. It has been shown that suppressing a gene for stearoyl acyl carrier protein fatty-acid desaturase (SACPD) enhances the resistance of Arabidopsis (SSI2) and soybean to multiple pathogens. In this study, we present functional analyses of a rice homolog of SSI2 (OsSSI2) in disease resistance of rice plants. A transposon insertion mutation (Osssi2-Tos17) and RNAi-mediated knockdown of OsSSI2 (OsSSI2-kd) reduced the oleic acid (18:1) level and increased that of stearic acid (18:0), indicating that OsSSI2 is responsible for fatty-acid desaturase activity. These plants displayed spontaneous lesion formation in leaf blades, retarded growth, slight increase in endogenous free salicylic acid (SA) levels, and SA/benzothiadiazole (BTH)-specific inducible genes, including WRKY45, a key regulator of SA/BTH-induced resistance, in rice. Moreover, the OsSSI2-kd plants showed markedly enhanced resistance to the blast fungus Magnaporthe grisea and leaf-blight bacteria Xanthomonas oryzae pv. oryzae. These results suggest that OsSSI2 is involved in the negative regulation of defense responses in rice, as are its Arabidopsis and soybean counterparts. Microarray analyses identified 406 genes that were differentially expressed (>or=2-fold) in OsSSI2-kd rice plants compared with wild-type rice and, of these, approximately 39% were BTH responsive. Taken together, our results suggest that induction of SA-responsive genes, including WRKY45, is likely responsible for enhanced disease resistance in OsSSI2-kd rice plants.

Grain Accumulation of Selenium Species in Rice (Oryza sativa L.)

EPA Science Inventory

Selenium (Se) is an essential micronutrient in which up to 1 billion people worldwide are deficient, causing a range of health disorders and potentially an increased risk of certain cancers. Consequently, there is much interest in Se biofortification of rice, the staple food for...

Comparative studies of Titanium Dioxide and Zinc Oxide as a potential filler in Polypropylene reinforced rice husk composite

NASA Astrophysics Data System (ADS)

Awang, M.; Mohd, W. R. Wan

2018-04-01

Arising global environmental issues have triggered the search of new products and processes that are compatible with the environment while maintaining novel properties of materials. In this work, green composites containing rice husk (RH), polypropylene (PP), and incorporated with two different fillers namely titanium dioxide (TiO2) and zinc oxide (ZnO) were prepared using an internal mixer and were injected into desired specimen by using an injection molding method. Mechanical properties of the composite were studied using Instron universal testing machine with load cell of 30kN capacity. Morphological of tensile fractured surface of composites was observed using scanning electron microscopy (SEM). The results show that the composites with the addition of TiO2 gave an excellent mechanical properties than the composites filled with ZnO. Furthermore, morphological image of PP/RH/TiO2 also shows a good interaction occurred between polymer matrix and RH particles as compared to that of PP/RH/ZnO.

Surviving floods: leaf gas films improve O₂ and CO₂ exchange, root aeration, and growth of completely submerged rice.

PubMed

Pedersen, Ole; Rich, Sarah Meghan; Colmer, Timothy David

2009-04-01

When completely submerged, the leaves of some species retain a surface gas film. Leaf gas films on submerged plants have recently been termed 'plant plastrons', analogous with the plastrons of aquatic insects. In aquatic insects, surface gas layers (i.e. plastrons) enlarge the gas-water interface to promote O₂ uptake when under water; however, the function of leaf gas films has rarely been considered. The present study demonstrates that gas films on leaves of completely submerged rice facilitate entry of O₂ from floodwaters when in darkness and CO₂ entry when in light. O₂ microprofiles showed that the improved gas exchange was not caused by differences in diffusive boundary layers adjacent to submerged leaves with or without gas films; instead, reduced resistance to gas exchange was probably due to the enlarged water-gas interface (cf. aquatic insects). When gas films were removed artificially, underwater net photosynthesis declined to only 20% of the rate with gas films present, such that, after 7 days of complete submergence, tissue sugar levels declined, and both shoot and root growth were reduced. Internal aeration of roots in anoxic medium, when shoots were in aerobic floodwater in darkness or when in light, was improved considerably when leaf gas films were present. Thus, leaf gas films contribute to the submergence tolerance of rice, in addition to those traits already recognized, such as the shoot-elongation response, aerenchyma and metabolic adjustments to O₂ deficiency and oxidative stress. © 2009 The Authors. Journal compilation © 2009 Blackwell Publishing Ltd.

The growth and uptake of Ga and In of rice (Oryza sative L.) seedlings as affected by Ga and In concentrations in hydroponic cultures.

PubMed

Syu, Chien-Hui; Chien, Po-Hsuan; Huang, Chia-Chen; Jiang, Pei-Yu; Juang, Kai-Wei; Lee, Dar-Yuan

2017-01-01

Limited information is available on the effects of gallium (Ga) and indium (In) on the growth of paddy rice. The Ga and In are emerging contaminants and widely used in high-tech industries nowadays. Understanding the toxicity and accumulation of Ga and In by rice plants is important for reducing the effect on rice production and exposure risk to human by rice consumption. Therefore, this study investigates the effect of Ga and In on the growth of rice seedlings and examines the accumulation and distribution of those elements in plant tissues. Hydroponic cultures were conducted in phytotron glasshouse with controlled temperature and relative humidity conditions, and the rice seedlings were treated with different levels of Ga and In in the nutrient solutions. The growth index and the concentrations of Ga and In in roots and shoots of rice seedlings were measured after harvesting. A significant increase in growth index with increasing Ga concentrations in culture solutions (<10mgGaL -1 ) was observed. In addition, the uptake of N, K, Mg, Ca, Mn by rice plants was also enhanced by Ga. However, the growth inhibition were observed while the In concentrations higher than 0.08mgL -1 , and the nutrients accumulated in rice plants were also significant decreased after In treatments. Based on the dose-response curve, we observed that the EC 10 (effective concentration resulting in 10% growth inhibition) value for In treatment was 0.17mgL -1 . The results of plant analysis indicated that the roots were the dominant sink of Ga and In in rice seedlings, and it was also found that the capability of translocation of Ga from roots to shoots were higher than In. In addition, it was also found that the PT 10 (threshold concentration of phytotoxicity resulting in 10% growth retardation) values based on shoot height and total biomass for In were 15.4 and 10.6μgplant -1 , respectively. The beneficial effects on the plant growth of rice seedlings were found by the addition of Ga in culture solutions. In contrast, the In treatments led to growth inhibition of rice seedlings. There were differences in the phytotoxicity, uptake, and translocation of the two emerging contaminants in rice seedlings. Copyright © 2016 Elsevier Inc. All rights reserved.

Unravelling the origin of the giant Zn deficiency in wurtzite type ZnO nanoparticles

PubMed Central

Renaud, Adèle; Cario, Laurent; Rocquelfelte, Xavier; Deniard, Philippe; Gautron, Eric; Faulques, Eric; Das, Tilak; Cheviré, François; Tessier, Franck; Jobic, Stéphane

2015-01-01

Owing to its high technological importance for optoelectronics, zinc oxide received much attention. In particular, the role of defects on its physical properties has been extensively studied as well as their thermodynamical stability. In particular, a large concentration of Zn vacancies in ZnO bulk materials is so far considered highly unstable. Here we report that the thermal decomposition of zinc peroxide produces wurtzite-type ZnO nanoparticles with an extraordinary large amount of zinc vacancies (>15%). These Zn vacancies segregate at the surface of the nanoparticles, as confirmed by ab initio calculations, to form a pseudo core-shell structure made of a dense ZnO sphere coated by a Zn free oxo-hydroxide mono layer. In others terms, oxygen terminated surfaces are privileged over zinc-terminated surfaces for passivation reasons what accounts for the Zn off-stoichiometry observed in ultra-fine powdered samples. Such Zn-deficient Zn1-xO nanoparticles exhibit an unprecedented photoluminescence signature suggesting that the core-shell-like edifice drastically influences the electronic structure of ZnO. This nanostructuration could be at the origin of the recent stabilisation of p-type charge carriers in nitrogen-doped ZnO nanoparticles. PMID:26333510

The application dosage of Azolla pinnata in fresh and powder form as organic fertilizer on soil chemical properties, growth and yield of rice plant

NASA Astrophysics Data System (ADS)

Setiawati, Mieke Rochimi; Damayani, Maya; Herdiyantoro, Diyan; Suryatmana, Pujawati; Anggraini, Derisfha; Khumairah, Fiqriah Hanum

2018-02-01

The yield of rice plants is strongly influenced by N fertilizer. Nitrogen in rice plants has roles in vegetative growth, tiller formation and increasing yield through rice protein formation. Nitrogen supplied from organic fertilizers is better than inorganic fertilizers that may have environmental problem effects. Organic fertilizers from Azolla pinnata water fern contain higher N than other organic fertilizers. Symbiosis between A. pinnata and the N-fixing cyanobacteria results in high content of nitrogen, 3 to 5%. A. pinnata can be added to the rice field as organic fertilizer in form of fresh biomass or composted. Composted form can be ground into powder which passes through 100 mesh sieve. Preparation of compost powder of A. pinnata is done to reduce the constraints of voluminous application of organic fertilizers and to improve the efficiency of its use. The objective of this research was to compare the effect of the use of fresh A. pinnata and compost powder of A. pinnata on some soil and plant chemical properties and rice yield. The treatments applied were fresh A. pinnata at the dose of 0, 10 and 20 ton ha-1 and A. pinnata compost powder at 12.5 and 25 kg ha-1. The results showed that incorporation of fresh A. pinnata at 20 tons ha-1 and its compost powder at 25 kg ha-1 increased the available P of soil, plant P content and tiller number, but did not affect the content of organic-C, total soil N, plant N content and rice yield. This study suggested the benefits of A. pinnata compost powder technology in organic fertilization of soil to increase the nutrient content of soil and rice plants.

Generation of poly-β-hydroxybutyrate from acetate in higher plants: Detection of acetoacetyl CoA reductase- and PHB synthase- activities in rice.

PubMed

Tsuda, Hirohisa; Shiraki, Mari; Inoue, Eri; Saito, Terumi

2016-08-20

It has been reported that Poly-β-hydroxybutyrate (PHB) is generated from acetate in the rice root. However, no information is available about the biosynthetic pathway of PHB from acetate in plant cells. In the bacterium Ralstonia eutropha H16 (R. eutropha), PHB is synthesized from acetyl CoA by the consecutive reaction of three enzymes: β-ketothiolase (EC: 2.3.1.9), acetoacetyl CoA reductase (EC: 1.1.1.36) and PHB synthase (EC: 2.3.1.-). Thus, in this study, we examined whether the above three enzymatic activities were also detected in rice seedlings. The results clearly showed that the activities of the above three enzymes were all detected in rice. In particular, the PHB synthase activity was detected specifically in the sonicated particulate fractions (2000g 10min precipitate (ppt) and the 8000g 30min ppt) of rice roots and leaves. In addition to these enzyme activities, several new experimental results were obtained on PHB synthesis in higher plants: (a) (14)C-PHB generated from 2-(14)C-acetate was mainly localized in the 2000g 10min ppt and the 8000g 30min ppt of rice root. (b) Addition of acetate (0.1-10mM) to culture medium of rice seedlings did not increase the content of PHB in the rice root or leaf. (c) In addition to C3 plants, PHB was generated from acetate in a C4 plant (corn) and in a CAM plant (Bryophyllum pinnatum). d) Washing with ethylenediaminetetraacetic acid (EDTA) strongly suggested that the PHB synthesized from acetate was of plant origin and was not bacterial contamination. Copyright © 2016 Elsevier GmbH. All rights reserved.

Repression of Esophageal Neoplasia and Inflammatory Signaling by Anti-miR-31 Delivery In Vivo

PubMed Central

Taccioli, Cristian; Garofalo, Michela; Chen, Hongping; Jiang, Yubao; Tagliazucchi, Guidantonio Malagoli; Di Leva, Gianpiero; Alder, Hansjuerg; Fadda, Paolo; Middleton, Justin; Smalley, Karl J.; Selmi, Tommaso; Naidu, Srivatsava; Farber, John L.; Croce, Carlo M.

2015-01-01

Background: Overexpression of microRNA-31 (miR-31) is implicated in the pathogenesis of esophageal squamous cell carcinoma (ESCC), a deadly disease associated with dietary zinc deficiency. Using a rat model that recapitulates features of human ESCC, the mechanism whereby Zn regulates miR-31 expression to promote ESCC is examined. Methods: To inhibit in vivo esophageal miR-31 overexpression in Zn-deficient rats (n = 12–20 per group), locked nucleic acid–modified anti-miR-31 oligonucleotides were administered over five weeks. miR-31 expression was determined by northern blotting, quantitative polymerase chain reaction, and in situ hybridization. Physiological miR-31 targets were identified by microarray analysis and verified by luciferase reporter assay. Cellular proliferation, apoptosis, and expression of inflammation genes were determined by immunoblotting, caspase assays, and immunohistochemistry. The miR-31 promoter in Zn-deficient esophagus was identified by ChIP-seq using an antibody for histone mark H3K4me3. Data were analyzed with t test and analysis of variance. All statistical tests were two-sided. Results: In vivo, anti-miR-31 reduced miR-31 overexpression (P = .002) and suppressed the esophageal preneoplasia in Zn-deficient rats. At the same time, the miR-31 target Stk40 was derepressed, thereby inhibiting the STK40-NF-κΒ–controlled inflammatory pathway, with resultant decreased cellular proliferation and activated apoptosis (caspase 3/7 activities, fold change = 10.7, P = .005). This same connection between miR-31 overexpression and STK40/NF-κΒ expression was also documented in human ESCC cell lines. In Zn-deficient esophagus, the miR-31 promoter region and NF-κΒ binding site were activated. Zn replenishment restored the regulation of this genomic region and a normal esophageal phenotype. Conclusions: The data define the in vivo signaling pathway underlying interaction of Zn deficiency and miR-31 overexpression in esophageal neoplasia and provide a mechanistic rationale for miR-31 as a therapeutic target for ESCC. PMID:26286729

A mathematical model of transmission of rice tungro disease by Nephotettix Virescens

NASA Astrophysics Data System (ADS)

Blas, Nikki T.; Addawe, Joel M.; David, Guido

2016-11-01

One of the major threats in rice agriculture is the Tungro virus, which is transmitted semi-persistently to rice plants via green rice leafhoppers called Nephotettix Virescens. Tungro is polycyclic and complex disease of rice associated by dual infection with Rice Tungro Bacilliform Virus (RTBV) and Rice Tungro Spherical Virus (RTSV). Interaction of the two viruses results in the degeneration of the host. In this paper, we used a plant-vector system of ordinary differential equations to model the spread of the disease in a model rice field. Parameter values were obtained from studies on the entomology of Nephotettix Virescens and infection rates of RTSV and RTBV. The system was analyzed for equilibrium solutions, and solved numerically for susceptible rice varieties (Taichung Native 1).

Expression of Arabidopsis glycine-rich RNA-binding protein AtGRP2 or AtGRP7 improves grain yield of rice (Oryza sativa) under drought stress conditions.

PubMed

Yang, Deok Hee; Kwak, Kyung Jin; Kim, Min Kyung; Park, Su Jung; Yang, Kwang-Yeol; Kang, Hunseung

2014-01-01

Although posttranscriptional regulation of RNA metabolism is increasingly recognized as a key regulatory process in plant response to environmental stresses, reports demonstrating the importance of RNA metabolism control in crop improvement under adverse environmental stresses are severely limited. To investigate the potential use of RNA-binding proteins (RBPs) in developing stress-tolerant transgenic crops, we generated transgenic rice plants (Oryza sativa) that express Arabidopsis thaliana glycine-rich RBP (AtGRP) 2 or 7, which have been determined to harbor RNA chaperone activity and confer stress tolerance in Arabidopsis, and analyzed the response of the transgenic rice plants to abiotic stresses. AtGRP2- or AtGRP7-expressing transgenic rice plants displayed similar phenotypes comparable with the wild-type plants under high salt or cold stress conditions. By contrast, AtGRP2- or AtGRP7-expressing transgenic rice plants showed much higher recovery rates and grain yields compared with the wild-type plants under drought stress conditions. The higher grain yield of the transgenic rice plants was due to the increases in filled grain numbers per panicle. Collectively, the present results show the importance of posttranscriptional regulation of RNA metabolism in plant response to environmental stress and suggest that GRPs can be utilized to improve the yield potential of crops under stress conditions. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Rice yellow stunt rhabdovirus protein 6 suppresses systemic RNA silencing by blocking RDR6-mediated secondary siRNA synthesis.

PubMed

Guo, Hongyan; Song, Xiaoguang; Xie, Chuanmiao; Huo, Yan; Zhang, Fujie; Chen, Xiaoying; Geng, Yunfeng; Fang, Rongxiang

2013-08-01

The P6 protein of Rice yellow stunt rhabdovirus (RYSV) is a virion structural protein that can be phosphorylated in vitro. However its exact function remains elusive. We found that P6 enhanced the virulence of Potato virus X (PVX) in Nicotiana benthamiana and N. tabacum plants, suggesting that it might function as a suppressor of RNA silencing. We examined the mechanism of P6-mediated silencing suppression by transiently expressing P6 in both N. benthamiana leaves and rice protoplasts. Our results showed that P6 could repress the production of secondary siRNAs and inhibit systemic green fluorescent protein RNA silencing but did not interfere with local RNA silencing in N. benthamiana plants or in rice protoplasts. Intriguingly, P6 and RDR6 had overlapping subcellular localization and P6 bound both rice and Arabidopsis RDR6 in vivo. Furthermore, transgenic rice plants expressing P6 showed enhanced susceptibility to infection by Rice stripe virus. Hence, we propose that P6 is part of the RYSV's counter-defense machinery against the plant RNA silencing system and plays a role mainly in affecting RDR6-mediated secondary siRNA synthesis. Our work provides a new perspective on how a plant-infecting nucleorhabdovirus may counteract host RNA silencing-mediated antiviral defense.

Erythrocyte CuZn superoxide dismutase activity is decreased in iron-deficiency anemia.

PubMed

Olivares, M; Araya, M; Pizarro, F; Letelier, A

2006-09-01

Iron and copper are essential microminerals that are intimately related. The present study was performed to determine the effect of iron-deficiency anemia (IDA) and treatment with iron on laboratory indicators of copper status. Hemoglobin, mean corpuscular volume erythrocyte Zn protoporphyrin, serum ferritin, serum copper, serum ceruloplasmin, and erythrocyte CuZn-superoxide dismutase (SOD) activity were studied in 12 adult women with IDA before and after iron treatment for 60-90 d (100 mg/d Fe, as ferric polymaltose) and in 27 women with normal iron status. Prior to treatment with iron, serum copper and ceruloplasmin were not different between the groups and treatment with iron did not affect these measures. IDA women, before and after treatment with iron, presented a 2.9- and 2-fold decrease in erythrocyte CuZn-SOD activity compared to women with normal iron status (p < 0.001). Treatment with iron increased erythrocyte CuZn-SOD activity of the IDA group; however, this change was not statistically significant. In conclusion, CuZn-SOD activity is decreased in IDA. Measurement of this enzyme activity is not useful for evaluating copper nutrition in iron-deficient subjects.

Responses of Super Rice (Oryza sativa L.) to Different Planting Methods for Grain Yield and Nitrogen-Use Efficiency in the Single Cropping Season

PubMed Central

Chen, Song; Wang, Danying; Xu, Chunmei; Ji, Chenglin; Zhang, Xiaoguo; Zhao, Xia; Zhang, Xiufu; Chauhan, Bhagirath Singh

2014-01-01

To break the yield ceiling of rice production, a super rice project was developed in 1996 to breed rice varieties with super high yield. A two-year experiment was conducted to evaluate yield and nitrogen (N)-use response of super rice to different planting methods in the single cropping season. A total of 17 rice varieties, including 13 super rice and four non-super checks (CK), were grown under three N levels [0 (N0), 150 (N150), and 225 (N225) kg ha−1] and two planting methods [transplanting (TP) and direct-seeding in wet conditions (WDS)]. Grain yield under WDS (7.69 t ha−1) was generally lower than TP (8.58 t ha−1). However, grain yield under different planting methods was affected by N rates as well as variety groups. In both years, there was no difference in grain yield between super and CK varieties at N150, irrespective of planting methods. However, grain yield difference was dramatic in japonica groups at N225, that is, there was an 11.3% and 14.1% average increase in super rice than in CK varieties in WDS and TP, respectively. This suggests that high N input contributes to narrowing the yield gap in super rice varieties, which also indicates that super rice was bred for high fertility conditions. In the japonica group, more N was accumulated in super rice than in CK at N225, but no difference was found between super and CK varieties at N0 and N150. Similar results were also found for N agronomic efficiency. The results suggest that super rice varieties have an advantage for N-use efficiency when high N is applied. The response of super rice was greater under TP than under WDS. The results suggest that the need to further improve agronomic and other management practices to achieve high yield and N-use efficiency for super rice varieties in WDS. PMID:25111805

Responses of super rice (Oryza sativa L.) to different planting methods for grain yield and nitrogen-use efficiency in the single cropping season.

PubMed

Chen, Song; Wang, Danying; Xu, Chunmei; Ji, Chenglin; Zhang, Xiaoguo; Zhao, Xia; Zhang, Xiufu; Chauhan, Bhagirath Singh

2014-01-01

To break the yield ceiling of rice production, a super rice project was developed in 1996 to breed rice varieties with super high yield. A two-year experiment was conducted to evaluate yield and nitrogen (N)-use response of super rice to different planting methods in the single cropping season. A total of 17 rice varieties, including 13 super rice and four non-super checks (CK), were grown under three N levels [0 (N0), 150 (N150), and 225 (N225) kg ha-1] and two planting methods [transplanting (TP) and direct-seeding in wet conditions (WDS)]. Grain yield under WDS (7.69 t ha-1) was generally lower than TP (8.58 t ha-1). However, grain yield under different planting methods was affected by N rates as well as variety groups. In both years, there was no difference in grain yield between super and CK varieties at N150, irrespective of planting methods. However, grain yield difference was dramatic in japonica groups at N225, that is, there was an 11.3% and 14.1% average increase in super rice than in CK varieties in WDS and TP, respectively. This suggests that high N input contributes to narrowing the yield gap in super rice varieties, which also indicates that super rice was bred for high fertility conditions. In the japonica group, more N was accumulated in super rice than in CK at N225, but no difference was found between super and CK varieties at N0 and N150. Similar results were also found for N agronomic efficiency. The results suggest that super rice varieties have an advantage for N-use efficiency when high N is applied. The response of super rice was greater under TP than under WDS. The results suggest that the need to further improve agronomic and other management practices to achieve high yield and N-use efficiency for super rice varieties in WDS.

Cadmium dynamics in soil pore water and uptake by rice: Influences of soil-applied selenite with different water managements.

PubMed

Wan, Yanan; Camara, Aboubacar Younoussa; Yu, Yao; Wang, Qi; Guo, Tianliang; Zhu, Lina; Li, Huafen

2018-05-11

Cadmium (Cd) in rice grains is a potential threat to human health. This study investigated the effects of selenite fertilisation (0 mg kg -1 , 0.5 mg kg -1 , and 1.0 mg kg -1 ) on soil solution Cd dynamics and rice uptake. Rice was grown in two Cd-contaminated soils in Jiangxi and Hunan Provinces under two different sets of conditions: aerobic and flooded. The experiments were conducted in pots. The plants were harvested at the seedling stage and at maturity to determine their Cd levels. Soil solutions were also extracted during the growing season to monitor Cd dynamics. The results showed that in the Jiangxi soil (pH 5.25), Cd concentrations in the soil solutions, seedlings, and mature rice plants were higher under aerobic than under flooded water management conditions. In the Hunan soil (pH 7.26), however, flooding decreased Cd levels in the rice seedlings but not in mature plants. Selenite additions to the Hunan soil decreased Cd concentrations in the soil solutions and in the mature rice plants. These effects were not observed for the solutions or the plants from Jiangxi soil amended with selenite. Relative to the control treatment, 0.5 mg kg -1 selenite decreased the rice grain Cd content by 45.2% and 67.7% under aerobic and flooding conditions, respectively. The results demonstrated that water management regimes affected rice Cd uptake more effectively in Jiangxi than in Hunan soil, whereas selenite addition was more effective in Hunan than in Jiangxi soil. Selenite addition was also more effective at reducing rice grain Cd levels when it was applied under flooding than under aerobic conditions. Copyright © 2018 Elsevier Ltd. All rights reserved.

[The eye and nutrition].

PubMed

Amemiya, T

1999-12-01

To examine the effect of vitamins and trace elements on ocular tissue. Rats or mice were fed diets deficient in the trace elements Zn, Cu, Mn, Se, Mg, and Cr or in vitamins A, B12, C, and E. In some rats Al and vitamin A were injected in excessive amounts. We studied the conjunctiva, cornea, retina, and optic nerve with a light microscope, transmission and scanning electron microscopes, an energy dispersive X-ray analyser, and an ion microscope. Histochemical, cytochemical, and immunohistochemical techniques were applied to the pathological specimens. Deficiencies of Zn, Cu, Mn, and vitamins A, C and E caused a loss of goblet cells in the conjunctiva and a prominent decrease of microvilli and microplicae in the conjunctiva and cornea. The elements in the goblet cells were changed in these conditions. In addition, epithelial cells showed poor fibrous development and abnormal distribution of chromatin in the nucleus. Zn, Cu, Mn, and vitamins A and E deficiencies caused photoreceptor cells to degenerate and disappear. Se deficiency reduced the horizontal and amacrine cells. Vitamin B12 deficiency reduced nerve fibers in the nerve fiber layer of the retina. Mg deficiency induced multifocal necrosis in the retinal pigment epithelium and apoptotic nuclear changes in the photoreceptor cells. Cr deficiency showed abnormal phagocytosis of the photoreceptor outer segment discs in the retinal pigment epithelium. Vitamin B12 was found to be related to the circadian rhythm in the retina. Deficiencies of Zn, Cu, Mn, and vitamins A, B12, and E induced degeneration and disappearance of myelin lamellae in the myelinated optic nerve fibers. In hypervitaminosis A, lipid droplets appeared in the retinal pigment epithelium and alcohol dehydrogenase disappeared in the retinal pigment epithelium and photoreceptor outer segments. Excessive Al was toxic to the retina, which showed disappearance of photoreceptor cells. Al deposits were seen in dendrites and neurons in the outer plexiform layer. Zn seemed to be necessary for corneal epithelial cell wound healing. Trace elements usually are contained in enzymes, which have many metabolic functions. They are related to synthesis and breakdown of many substances. Some trace elements such as Zn, Cu, Mn, and Se and vitamins including vitamins A, C, and E prevent peroxidation of lipids. Some vitamins have an affinity for specific tissues such as epithelial cells, nerve fibers, and neuronal cells and are needed for cell differentiation, development, and maintenance. Cu, Zn, Mn, Se, Mg, and Cr and vitamins A, B12, C, and E are necessary for maintenance of cellular structure and metabolism.

The eye and nutrition

PubMed

Amemiya

2000-05-01

Purpose: To examine the effect of vitamins and trace elements on ocular tissue.Materials and Methods: Rats or mice were fed diets deficient in the trace elements Zn, Cu, Mn, Se, Mg, and Cr or in vitamins A, B(12), C, and E. In some rats Al and vitamin A were injected in excessive amounts. We studied the conjunctiva, cornea, retina, and optic nerve with a light microscope, transmission and scanning electron microscopes, an energy dispersive X-ray analyzer, and an ion microscope. Histochemical, cytochemical, and immunohistochemical techniques were applied to the pathological specimens.Results: Deficiencies of Zn, Cu, Mn, and vitamins A, C and E caused a loss of goblet cells in the conjunctiva and a prominent decrease of microvilli and microplicae in the conjunctiva and cornea. The elements in the goblet cells were changed in these conditions. In addition, epithelial cells showed poor fibrous development and abnormal distribution of chromatin in the nucleus.Zn, Cu, Mn, and vitamins A and E deficiencies caused photoreceptor cells to degenerate and disappear. Se deficiency reduced the horizontal and amacrine cells. Vitamin B(12) deficiency reduced nerve fibers in the nerve fiber layer of the retina. Mg deficiency induced multifocal necrosis in the retinal pigment epithelium and apoptotic nuclear changes in the photoreceptor cells. Cr deficiency showed abnormal phagocytosis of the photoreceptor outer segment discs in the retinal pigment epithelium. Vitamin B(12) was found to be related to the circadian rhythm in the retina.Deficiencies of Zn, Cu, Mn, and vitamins A, B(12), and E induced degeneration and disappearance of myelin lamellae in the myelinated optic nerve fibers.In hypervitaminosis A, lipid droplets appeared in the retinal pigment epithelium and alcohol dehydrogenase disappeared in the retinal pigment epithelium and photoreceptor outer segments. Excessive Al was toxic to the retina, which showed disappearance of photoreceptor cells. Al deposits were seen in dendrites and neurons in the outer plexiform layer.Zn seemed to be necessary for corneal epithelial cell wound healing.Discussion: Trace elements usually are contained in enzymes, which have many metabolic functions. They are related to synthesis and breakdown of many substances. Some trace elements such as Zn, Cu, Mn, and Se and vitamins including vitamins A, C, and E prevent peroxidation of lipids. Some vitamins have an affinity for specific tissues such as epithelial cells, nerve fibers, and neuronal cells and are needed for cell differentiation, development, and maintenance.Conclusion: Cu, Zn, Mn, Se, Mg, and Cr and vitamins A, B(12), C, and E are necessary for maintenance of cellular structure and metabolism.

OsAGSW1, an ABC1-like kinase gene, is involved in the regulation of grain size and weight in rice.

PubMed

Li, Tao; Jiang, Jieming; Zhang, Shengchun; Shu, Haoran; Wang, Yaqin; Lai, Jianbin; Du, Jinju; Yang, Chengwei

2015-09-01

Grain shape and weight are two determining agronomic traits of rice yield. ABC1 (Activity of bc1 complex) is a newly found atypical kinase in plants. Here, we report on an ABC1 protein kinase gene, OsAGSW1 (ABC1-like kinase related to Grain size and Weight). Expression of OsAGSW1-GFP in rice revealed that OsAGSW1 is localized to the chloroplasts in rice. Analysis of OsAGSW1 promoter::β-glucuronidase transgenic rice indicated that this gene was highly expressed in vascular bundles in shoot, hull and caryopsis. Furthermore, OsAGSW1-RNAi and overexpressed transgenic rice lines were generated. Stable transgenic lines overexpressing OsAGSW1 exhibited a phenotype with a significant increase in grain size, grain weight, grain filling rate and 1000-grain weight compared with the wild-type and RNAi transgenic plants. Microscopy analysis showed that spikelet hulls just before heading were different in the OsAGSW1-overexpressed plants compared with wild-type and OsAGSW1 RNAi rice. Further cytological analysis showed that the number of external parenchyma cells in rice hulls of OsAGSW1-overexpressed plants increased, leading to wider and longer spikelet hulls than those of the wild-type and OsAGSW1-RNAi plants. The vascular cross-sectional area in lemma, carpopodium and ovules also strikingly increased and area of both xylem and phloem were enlarged in the OsAGSW1-overexpressed plants. Thus, our results demonstrated that OsAGSW1 plays an important role in seed shape and size of rice by regulating the number of external parenchyma cells and the development of vascular bundles, providing a new insight into the functions of ABC1 genes in plants. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Dynamics of Zn in an urban wetland soil-plant system: Coupling isotopic and EXAFS approaches

NASA Astrophysics Data System (ADS)

Aucour, Anne-Marie; Bedell, Jean-Philippe; Queyron, Marine; Magnin, Valérie; Testemale, Denis; Sarret, Géraldine

2015-07-01

Plants play a key role in the stabilization of metals in contaminated environments. Studies have been performed on Zn uptake and storage mechanisms, mainly for Zn hyperaccumulating plants, though less is known about Zn stabilization in the rhizosphere of non-accumulating plants. This study was focused on the dynamics of Zn in a whole soil-litter-plant system and the processes controlling Zn mobilization and stabilization. The site studied was an infiltration basin receiving urban stormwater, in which Phalaris arundinacea (reed canary grass) developed spontaneously. A combination of chemical extractions (CaCl2, DTPA), EXAFS spectroscopy and Zn stable isotope measurements was applied for the water inlet, soil, plant organs and decaying biomass. Zn speciation changed from the water inlet to the soil. In the soil, Zn was present as Zn-layered double hydroxide (Zn-LDH), tetrahedral and octahedral sorbed Zn species. The formation of Zn-LDH participates in Zn stabilization. Tetrahedral Zn species, which were partly DTPA exchangeable, were enriched in heavy isotopes, whereas octahedral Zn (Zn-LDH and sorbed species) were enriched in light isotopes. Based on a linear model between δ66Zn and Zn speciation, δ66Zn for pure tetrahedral and octahedral end-members were estimated at ca. 0.33‰ and 0.04‰, respectively. In the plant, a mixture of octahedral Zn (attributed to aqueous Zn-organic acid complexes present in the symplasm), and tetrahedral Zn (attributed to apoplasmic Zn-cell wall complexes) was observed in all organs. Large enrichment in light isotopes from the soil to the plant Δ66Zn (of ca. -0.6‰) was observed. The stem was enriched in light isotopes versus roots and, to a lesser extent, versus leaves. The results suggest that Zn was taken up via a low-affinity transport system and that Zn was sequestrated in the stem symplasm after transit through leaves. Finally, intense Zn exchanges were observed between the decaying biomass and the soil, with the sorption of heavy Zn from the soil to cell wall remains and release of light Zn to the soil. Overall, this study provides a complete overview of Zn cycling in an urban wetland soil-plant system, and describes several changes in Zn speciation with Zn isotopic fractionation processes in a complex system.

Performance of hybrids between weedy rice and insect-resistant transgenic rice under field experiments: implication for environmental biosafety assessment.

PubMed

Cao, Qian-Jin; Xia, Hui; Yang, Xiao; Lu, Bao-Rong

2009-12-01

Transgene escape from genetically modified (GM) rice into weedy rice via gene flow may cause undesired environmental consequences. Estimating the field performance of crop-weed hybrids will facilitate our understanding of potential introgression of crop genes (including transgenes) into weedy rice populations, allowing for effective biosafety assessment. Comparative studies of three weedy rice strains and their hybrids with two GM rice lines containing different insect-resistance transgenes (CpTI or Bt/CpTI) indicated an enhanced relative performance of the crop-weed hybrids, with taller plants, more tillers, panicles, and spikelets per plant, as well as higher 1 000-seed weight, compared with the weedy rice parents, although the hybrids produced less filled seeds per plant than their weedy parents. Seeds from the F(1) hybrids had higher germination rates and produced more seedlings than the weedy parents, which correlated positively with 1 000-seed weight. The crop-weed hybrids demonstrated a generally enhanced relative performance than their weedy rice parents in our field experiments. These findings indicate that transgenes from GM rice can persist to and introgress into weedy rice populations through recurrent crop-to-weed gene flow with the aid of slightly increased relative fitness in F(1) hybrids.

Transcription activator-like (TAL) effectors targeting OsSWEET genes enhance virulence on diverse rice (Oryza sativa) varieties when expressed individually in a TAL effector-deficient strain of Xanthomonas oryzae.

PubMed

Verdier, Valérie; Triplett, Lindsay R; Hummel, Aaron W; Corral, Rene; Cernadas, R Andres; Schmidt, Clarice L; Bogdanove, Adam J; Leach, Jan E

2012-12-01

Genomes of the rice (Oryza sativa) xylem and mesophyll pathogens Xanthomonas oryzae pv. oryzae (Xoo) and pv. oryzicola (Xoc) encode numerous secreted transcription factors called transcription activator-like (TAL) effectors. In a few studied rice varieties, some of these contribute to virulence by activating corresponding host susceptibility genes. Some activate disease resistance genes. The roles of X. oryzae TAL effectors in diverse rice backgrounds, however, are poorly understood. Xoo TAL effectors that promote infection by activating SWEET sucrose transporter genes were expressed in TAL effector-deficient X. oryzae strain X11-5A, and assessed in 21 rice varieties. Some were also tested in Xoc on variety Nipponbare. Several Xoc TAL effectors were tested in X11-5A on four rice varieties. Xoo TAL effectors enhanced X11-5A virulence on most varieties, but to varying extents depending on the effector and variety. SWEET genes were activated in all tested varieties, but increased virulence did not correlate with activation level. SWEET activators also enhanced Xoc virulence on Nipponbare. Xoc TAL effectors did not alter X11-5A virulence. SWEET-targeting TAL effectors contribute broadly and non-tissue-specifically to virulence in rice, and their function is affected by host differences besides target sequences. Further, the utility of X11-5A for characterizing individual TAL effectors in rice was established. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

Effect of controlled zinc release on bone mineral density from injectable Zn-containing beta-tricalcium phosphate suspension in zinc-deficient diseased rats.

PubMed

Otsuka, Makoto; Ohshita, Yuko; Marunaka, Sunao; Matsuda, Yoshihia; Ito, Atsuo; Ichinose, Noboru; Otsuka, Kuniko; Higuchi, William I

2004-06-01

The purpose of this study was to evaluate the efficacy of zinc (Zn)-containing beta-tricalcium phosphate (Zn-TCP) in correcting the bone mineral deficiency noted in osteoporosis using ovariectomized rat model. Four rats were used for each of the four experimental groups: D0, D10, D20, and N10. The rats in D0, D10, and D20 groups were ovariectomized, and fed a vitamin D-, Ca-, and Zn-deficient diet, and induced Zn-deficient osteoporoses for 9 weeks. In contrast, the N10 group was the normal rats fed normal healthy diet for 9 weeks. D0 group was injected with pure beta-TCP suspension, D10 and D20 groups were injected with suspensions containing 10 mg of 10 mol % (6.17 wt % Zn) and 20 mol % (12.05 wt % Zn) Zn-TCP, respectively, and the healthy group, N10 were injected with 10 mol %. Zn-TCP suspensions. Injections were administered intramuscularly in the left thigh once a week in all rats, and fed a vitamin D- and Zn-deficient diet for 9 weeks. The plasma calcium (Ca) and Zn levels, plasma alkaline phosphatase activity (ALP) and bone mineral density (BMD) of the lumbar vertebra and femora were measured. The plasma Zn levels in all the rats were between 1.1 and 2.8 microg/mL. The areas under the curves for the Ca, Zn, and ALP (Ca-AUC, Zn-AUC, and ALP-AUC) levels between 0 and 63 days were calculated. Results for the AUCs were as follows: (1) the Zn-AUCs were in the order of N10 = D20 > D10 > D0; (2) the Ca-AUCs for D0, D10 groups were significantly lower than that for the N10 group; (3) the ALP-AUCs for the D10 and D20 groups were significantly higher than that for the N10 group, and that of the D0 group was in between those. The body weight of D10 and D20 groups significantly increased with time, that of the D0 group increased slightly, and that of the N10 group remained unchanged for the entire experimental period. The BMD of the lumbar vertebrae of the D10 and D20 groups (about 100 mg/cm(2)) was significantly higher than that of the D0 group but lower than that of the N10 group. The BMD of the left femur increased more than that of the right femur with the increase in the amount of Zn in the suspension. The results of this study suggest that the local effect on BMD was more pronounced than the effect on the whole body. Copyright 2004 Wiley Periodicals, Inc. J Biomed Mater Res 69A: 552-560, 2004

Golden Rice--five years on the road--five years to go?

PubMed

Al-Babili, Salim; Beyer, Peter

2005-12-01

Provitamin A accumulates in the grain of Golden Rice as a result of genetic transformation. In developing countries, where vitamin A deficiency prevails, grain from Golden Rice is expected to provide this important micronutrient sustainably through agriculture. Since its original production, the prototype Golden Rice has undergone intense research to increase the provitamin A content, to establish the scientific basis for its carotenoid complement, and to better comply with regulatory requirements. Today, the current focus is on how to get Golden Rice effectively into the hands of farmers, which is a novel avenue for public sector research, carried out with the aid of international research consortia. Additional new research is underway to further increase the nutritional value of Golden Rice.

Proposal of a growth chamber for growing Super-Dwarf Rice in Space Agriculture

NASA Astrophysics Data System (ADS)

Hirai, Hiroaki; Kitaya, Yoshiaki; Tsukamoto, Koya; Yamashita, Youichirou; Hirai, Takehiro

Space agriculture needs to be considered to supply food for space crew who stay in space over an extended time period. So far crops such as wheat, onion, oat, pea and lettuce grew to explore the possibility of space agriculture. Although rice is a staple food for most of the world, research on rice cultivation in space has not been done much. Rice grains are nutrient-rich with carbohydrate, protein and dietary fiber. Moreover, rice is a high yield crop and harvested grains have a long shelf life. However, the plant height of standard rice cultivars is relatively long, requiring much space. In addition, rice plants require higher light intensities for greater yield. For these reasons, it is difficult to establish facilities for rice culture in a limited space with a low cost. We propose to employee a super-dwarf cultivar and a small growth chamber with a new type of LEDs. The super-dwarf rice is a short-grain japonica variety and the plant height is approximately 20 cm that is one-fifth as tall as standard cultivars. The LED light used as a light source for this study can provide full spectrum of 380 nm to 750 nm. Air temperature and humidity were controlled by a Peltier device equipped in the chamber. The characteristics of the new type of LEDs and other equipments of the chamber and the ground based performance of super-dwarf rice plants grown in the chamber will be reported.

Transgenic expression of the dicotyledonous pattern recognition receptor EFR in rice leads to ligand-dependent activation of defense responses.

PubMed

Schwessinger, Benjamin; Bahar, Ofir; Thomas, Nicholas; Thomas, Nicolas; Holton, Nicolas; Nekrasov, Vladimir; Ruan, Deling; Canlas, Patrick E; Daudi, Arsalan; Petzold, Christopher J; Singan, Vasanth R; Kuo, Rita; Chovatia, Mansi; Daum, Christopher; Heazlewood, Joshua L; Zipfel, Cyril; Ronald, Pamela C

2015-03-01

Plant plasma membrane localized pattern recognition receptors (PRRs) detect extracellular pathogen-associated molecules. PRRs such as Arabidopsis EFR and rice XA21 are taxonomically restricted and are absent from most plant genomes. Here we show that rice plants expressing EFR or the chimeric receptor EFR::XA21, containing the EFR ectodomain and the XA21 intracellular domain, sense both Escherichia coli- and Xanthomonas oryzae pv. oryzae (Xoo)-derived elf18 peptides at sub-nanomolar concentrations. Treatment of EFR and EFR::XA21 rice leaf tissue with elf18 leads to MAP kinase activation, reactive oxygen production and defense gene expression. Although expression of EFR does not lead to robust enhanced resistance to fully virulent Xoo isolates, it does lead to quantitatively enhanced resistance to weakly virulent Xoo isolates. EFR interacts with OsSERK2 and the XA21 binding protein 24 (XB24), two key components of the rice XA21-mediated immune response. Rice-EFR plants silenced for OsSERK2, or overexpressing rice XB24 are compromised in elf18-induced reactive oxygen production and defense gene expression indicating that these proteins are also important for EFR-mediated signaling in transgenic rice. Taken together, our results demonstrate the potential feasibility of enhancing disease resistance in rice and possibly other monocotyledonous crop species by expression of dicotyledonous PRRs. Our results also suggest that Arabidopsis EFR utilizes at least a subset of the known endogenous rice XA21 signaling components.

Transgenic Expression of the Dicotyledonous Pattern Recognition Receptor EFR in Rice Leads to Ligand-Dependent Activation of Defense Responses

PubMed Central

Thomas, Nicolas; Holton, Nicolas; Nekrasov, Vladimir; Ruan, Deling; Canlas, Patrick E.; Daudi, Arsalan; Petzold, Christopher J.; Singan, Vasanth R.; Kuo, Rita; Chovatia, Mansi; Daum, Christopher; Heazlewood, Joshua L.; Zipfel, Cyril; Ronald, Pamela C.

2015-01-01

Plant plasma membrane localized pattern recognition receptors (PRRs) detect extracellular pathogen-associated molecules. PRRs such as Arabidopsis EFR and rice XA21 are taxonomically restricted and are absent from most plant genomes. Here we show that rice plants expressing EFR or the chimeric receptor EFR::XA21, containing the EFR ectodomain and the XA21 intracellular domain, sense both Escherichia coli- and Xanthomonas oryzae pv. oryzae (Xoo)-derived elf18 peptides at sub-nanomolar concentrations. Treatment of EFR and EFR::XA21 rice leaf tissue with elf18 leads to MAP kinase activation, reactive oxygen production and defense gene expression. Although expression of EFR does not lead to robust enhanced resistance to fully virulent Xoo isolates, it does lead to quantitatively enhanced resistance to weakly virulent Xoo isolates. EFR interacts with OsSERK2 and the XA21 binding protein 24 (XB24), two key components of the rice XA21-mediated immune response. Rice-EFR plants silenced for OsSERK2, or overexpressing rice XB24 are compromised in elf18-induced reactive oxygen production and defense gene expression indicating that these proteins are also important for EFR-mediated signaling in transgenic rice. Taken together, our results demonstrate the potential feasibility of enhancing disease resistance in rice and possibly other monocotyledonous crop species by expression of dicotyledonous PRRs. Our results also suggest that Arabidopsis EFR utilizes at least a subset of the known endogenous rice XA21 signaling components. PMID:25821973

Mechanism study of sulfur fertilization mediating copper translocation and biotransformation in rice (Oryza sativa L.) plants.

PubMed

Sun, Lijuan; Yang, Jianjun; Fang, Huaxiang; Xu, Chen; Peng, Cheng; Huang, Haomin; Lu, Lingli; Duan, Dechao; Zhang, Xiangzhi; Shi, Jiyan

2017-07-01

Metabolism of sulfur (S) is suggested to be an important factor for the homeostasis and detoxification of Cu in plants. We investigated the effects of S fertilizers (S 0 , Na 2 SO 4 ) on Cu translocation and biotransformation in rice plants by using multiple synchrotron-based techniques. Fertilization of S increased the biomass and yield of rice plants, as well as the translocation factor of Cu from root to shoot and shoot to grain, resulting in enhanced Cu in grain. Sulfur K-edge X-ray near edge structure (XANES) analysis showed that fertilization of S increased the concentration of glutathione in different rice tissues, especially in rice stem and leaf. Copper K-edge XANES results indicated that a much higher proportion of Cu (I) species existed in rice grain than husk and leaf, which was further confirmed by soft X-ray scanning transmission microscopy results. Sulfur increased the proportion of Cu (I) species in rice grain, husk and leaf, suggesting the inducing of Cu (II) reduction in rice tissues by S fertilization. These results suggested that fertilization of S in paddy soils increased the accumulation of Cu in rice grain, possibly due to the reduction of Cu (II) to Cu (I) by enhancing glutathione synthesis and increasing the translocation of Cu from shoot to grain. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of depth of flooding on the rice water weevil, Lissorhoptrus oryzophilus, and yield of rice.

PubMed

Tindall, Kelly V; Bernhardt, John L; Stout, Michael J; Beighley, Donn H

2013-01-01

The rice water weevil, Lissorhoptrus oryzophilus (Kuschel) (Coleoptera: Curculionidae), is a semi-aquatic pest of rice and is the most destructive insect pest of rice in the United States. Adults oviposit after floods are established, and greenhouse studies have shown that plants exposed to deep floods have more eggs oviposited in leaf sheaths than plants exposed to a shallow flood. Experiments were conducted in three mid-southern states in the USA to determine if the depth of flooding would impact numbers of L. oryzophilus on rice plants under field conditions. Rice was flooded at depths of approximately 5 or 10 cm in Arkansas in 2007 and 2008 and Louisiana in 2008, and at depths between 0-20 cm in Missouri in 2008. Plants were sampled three and four weeks after floods were established in all locations, and also two weeks after flood in Missouri. On all sampling dates in four experiments over two years and at three field sites, fewer L. oryzophilus larvae were collected from rice in shallow-flooded plots than from deep-flooded plots. The number of L. oryzophilus was reduced by as much as 27% in shallow-flooded plots. However, the reduction in insect numbers did not translate to a significant increase in rice yield. We discuss how shallow floods could be used as a component of an integrated pest management program for L. oryzophilus.

Fenton process-affected transformation of roxarsone in paddy rice soils: Effects on plant growth and arsenic accumulation in rice grain.

PubMed

Qin, Junhao; Li, Huashou; Lin, Chuxia

2016-08-01

Batch and greenhouse experiments were conducted to examine the effects of Fenton process on transformation of roxarsone in soils and its resulting impacts on the growth of and As uptake by a rice plant cultivar. The results show that addition of Fenton reagent markedly accelerated the degradation of roxarsone and produced arsenite, which was otherwise absent in the soil without added Fenton reagent. Methylation of arsenate was also enhanced by Fenton process in the earlier part of the experiment due to abundant supply of arsenate from Roxarsone degradation. Overall, addition of Fenton reagent resulted in the predominant presence of arsenate in the soils. Fenton process significantly improved the growth of rice in the maturity stage of the first crop, The concentration of methylated As species in the rice plant tissues among the different growth stages was highly variable. Addition of Fenton reagent into the soils led to reduced uptake of soil-borne As by the rice plants and this had a significant effect on reducing the accumulation of As in rice grains. The findings have implications for understanding As biogeochemistry in paddy rice field receiving rainwater-borne H2O2 and for development of mitigation strategies to reduce accumulation of As in rice grains. Copyright © 2016 Elsevier Inc. All rights reserved.

Effect of Depth of Flooding on the Rice Water Weevil, Lissorhoptrus oryzophilus, and Yield of Rice

PubMed Central

Tindall, Kelly V.; Bernhardt, John L.; Stout, Michael J.; Beighley, Donn H.

2013-01-01

The rice water weevil, Lissorhoptrus oryzophilus (Kuschel) (Coleoptera: Curculionidae), is a semi-aquatic pest of rice and is the most destructive insect pest of rice in the United States. Adults oviposit after floods are established, and greenhouse studies have shown that plants exposed to deep floods have more eggs oviposited in leaf sheaths than plants exposed to a shallow flood. Experiments were conducted in three mid-southern states in the USA to determine if the depth of flooding would impact numbers of L. oryzophilus on rice plants under field conditions. Rice was flooded at depths of approximately 5 or 10 cm in Arkansas in 2007 and 2008 and Louisiana in 2008, and at depths between 0–20 cm in Missouri in 2008. Plants were sampled three and four weeks after floods were established in all locations, and also two weeks after flood in Missouri. On all sampling dates in four experiments over two years and at three field sites, fewer L. oryzophilus larvae were collected from rice in shallow-flooded plots than from deep-flooded plots. The number of L. oryzophilus was reduced by as much as 27% in shallow-flooded plots. However, the reduction in insect numbers did not translate to a significant increase in rice yield. We discuss how shallow floods could be used as a component of an integrated pest management program for L. oryzophilus. PMID:23906324

Arsenic accumulation in rice (Oryza sativa L.) is influenced by environment and genetic factors.

PubMed

Kumarathilaka, Prasanna; Seneweera, Saman; Meharg, Andrew; Bundschuh, Jochen

2018-06-13

Arsenic (As) elevation in paddy soils will have a negative impact on both the yield and grain quality of rice (Oryza sativa L.). The mechanistic understanding of As uptake, translocation, and grain filling is an important aspect to produce rice grains with low As concentrations through agronomical, physico-chemical, and breeding approaches. A range of factors (i.e. physico-chemical, biological, and environmental) govern the speciation and mobility of As in paddy soil-water systems. Major As uptake transporters in rice roots, such as phosphate and aquaglyceroporins, assimilate both inorganic (As(III) and As(V)) and organic As (DMA(V) and MMA(V)) species from the rice rhizosphere. A number of metabolic pathways (i.e. As (V) reduction, As(III) efflux, and As(III)-thiol complexation and subsequent sequestration) are likely to play a key role in determining the translocation and substantial accumulation of As species in rice tissues. The order of translocation efficiency (caryopsis-to-root) for different As species in rice plants is comprehensively evaluated as follows: DMA(V) > MMA(V) > inorganic As species. The loading patterns of both inorganic and organic As species into the rice grains are largely dependent on the genetic makeup and maturity stage of the rice plants together with environmental interactions. The knowledge of As metabolism in rice plants and how it is affected by plant genetics and environmental factors would pave the way to develop adaptive strategies to minimize the accumulation of As in rice grains. Copyright © 2018 Elsevier B.V. All rights reserved.

A built-in mechanism to mitigate the spread of insect-resistance and herbicide-tolerance transgenes into weedy rice populations.

PubMed

Liu, Chengyi; Li, Jingjing; Gao, Jianhua; Shen, Zhicheng; Lu, Bao-Rong; Lin, Chaoyang

2012-01-01

The major challenge of cultivating genetically modified (GM) rice (Oryza sativa) at the commercial scale is to prevent the spread of transgenes from GM cultivated rice to its coexisting weedy rice (O. sativa f. spontanea). The strategic development of GM rice with a built-in control mechanism can mitigate transgene spread in weedy rice populations. An RNAi cassette suppressing the expression of the bentazon detoxifying enzyme CYP81A6 was constructed into the T-DNA which contained two tightly linked transgenes expressing the Bt insecticidal protein Cry1Ab and the glyphosate tolerant 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), respectively. GM rice plants developed from this T-DNA were resistant to lepidopteran pests and tolerant to glyphosate, but sensitive to bentazon. The application of bentazon of 2000 mg/L at the rate of 40 mL/m(2), which is approximately the recommended dose for the field application to control common rice weeds, killed all F(2) plants containing the transgenes generated from the Crop-weed hybrids between a GM rice line (CGH-13) and two weedy rice strains (PI-63 and PI-1401). Weedy rice plants containing transgenes from GM rice through gene flow can be selectively killed by the spray of bentazon when a non-GM rice variety is cultivated alternately in a few-year interval. The built-in control mechanism in combination of cropping management is likely to mitigate the spread of transgenes into weedy rice populations.

Evaluation of Mercury Uptake and Distribution in Rice (Oryza sativa L.).

PubMed

Hang, Xiaoshuai; Gan, Fangqun; Chen, Yudong; Chen, Xiaoqin; Wang, Huoyan; Du, Changwen; Zhou, Jianmin

2018-03-01

Mercury (Hg) contamination in soil-rice systems from industry, mining and agriculture has received increasing attention recently in China. Pot experiments were conducted to research the Hg accumulation capacity of rice under exogenous Hg in the soil and study the major soil factors affecting translocation of Hg from soil to plant. Soil treated with 2 mg kg -1 Hg decreased rice grain yield and inhibited the growth of rice plants. With increased Hg contamination of the rice, the enrichment rate of Hg was significantly higher in the rice grain than that in the stalk and leaf. Soil pH and cation exchange capacity are the key factors controlling Hg bioavailability in soils.

Temperature-sensitive albino gene TCD5, encoding a monooxygenase, affects chloroplast development at low temperatures.

PubMed

Wang, Yufeng; Zhang, Jianhui; Shi, Xiaoliang; Peng, Yu; Li, Ping; Lin, Dongzhi; Dong, Yanjun; Teng, Sheng

2016-09-01

Chloroplasts are essential for photosynthesis and play critical roles in plant development. In this study, we characterized the temperature-sensitive chlorophyll-deficient rice mutant tcd5, which develops albino leaves at low temperatures (20 °C) and normal green leaves at high temperatures (32 °C). The development of chloroplasts and etioplasts is impaired in tcd5 plants at 20 °C, and the temperature-sensitive period for the albino phenotype is the P4 stage of leaf development. The development of thylakoid membranes is arrested at the mid-P4 stage in tcd5 plants at 20 °C. We performed positional cloning of TCD5 and then complementation and knock-down experiments, and the results showed that the transcript LOC_Os05g34040.1 from the LOC_Os05g34040 gene corresponded to the tcd5 phenotype. TCD5 encodes a conserved plastid-targeted monooxygenase family protein which has not been previously reported associated with a temperature-sensitive albino phenotype in plants. TCD5 is abundantly expressed in young leaves and immature spikes, and low temperatures increased this expression. The transcription of some genes involved in plastid transcription/translation and photosynthesis varied in the tcd5 mutant. Although the phenotype and temperature dependence of the TCD5 orthologous mutant phenotype were different in rice and Arabidopsis, OsTCD5 could rescue the phenotype of the Arabidopsis mutant, suggesting that TCD5 function is conserved between monocots and dicots. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

[Interaction among the trace elements zinc, copper and iron after depletion and repletion of dairy cows with zinc].

PubMed

Kirchgessner, M; Schwarz, F J; Roth, H P; Schwarz, W A

1978-12-01

Imbalances in the supply with trace elements may be caused by the excessive administration of one or several elements or the insufficient administration in relation to other trace elements. This article deals with the interactions between the trace elements zinc and copper resp. zinc and iron under the conditions of the insufficient supply with Zn (6 mg per kg dry matter of the fodder) and the supply according to the demand with other trace elements (14 mg copper resp. 83 mg iron per dry matter of the fodder). For this purpose we investigated the copper, iron and zinc content of the milk and the serum of cows that were first depleted of zinc through a semi-synthetic zinc deficiency diet and then repleted with extra allowances of zinc. The closest connections exist between the copper and zinc content of the milk. Thus extreme Zn-deficiency feeding conditions the decreased Zn-content on the one hand and increased Cu-content on the other. In contrast to this, the cows' Zn-excretion in the milk increases after Zn-repletion whereas the Cu-content decreases. This shows a distinctly negative correlation. A loose connection could only be detected for the Cu- and Zn-content of the serum. Though the Zn-content changed considerably in dependence on the Zn-supply, the Cu-content remained largely uninfluenced. The Fe-content of both milk and serum shows no interaction with the nutritive Zn-supply. Only after 19 test weeks of extreme Zn-deficiency could a slight increase of the Fe-concentration be indicated.

Impact of volunteer rice infestation on yield and grain quality of rice.

PubMed

Singh, Vijay; Burgos, Nilda R; Singh, Shilpa; Gealy, David R; Gbur, Edward E; Caicedo, Ana L

2017-03-01

Volunteer rice (Oryza sativa L.) grains may differ in physicochemical traits from cultivated rice, which may reduce the quality of harvested rice grain. To evaluate the effect of volunteer rice on cultivated rice, fields were surveyed in Arkansas in 2012. Cropping history that included hybrid cultivars in the previous two years (2010 and 2011) had higher volunteer rice infestation (20%) compared with fields planted previously with inbred rice (5.5%). The total grain yield of rice was reduced by 0.4% for every 1% increase in volunteer rice density. The grain quality did not change in fields planted with the same cultivar for three years. Volunteer rice density of at least 7.6% negatively impacted the head rice and when infestation reached 17.7%, it also reduced the rice grain yield. The protein and amylose contents of rice were not affected until volunteer rice infestation exceeded 30%. Crop rotation systems that include hybrid rice are expected to have higher volunteer rice infestation than systems without hybrid rice. It is predicted that, at 8% infestation, volunteer rice will start to impact head rice yield and will reduce total yield at 18% infestation. It could alter the chemical quality of rice grain at >30% infestation. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Nitric oxide acts upstream of ethylene in cell wall phosphorus reutilization in phosphorus-deficient rice.

PubMed

Zhu, Xiao Fang; Zhu, Chun Quan; Wang, Chao; Dong, Xiao Ying; Shen, Ren Fang

2017-01-01

Nitric oxide (NO) and ethylene are both involved in cell wall phosphorus (P) reutilization in P-deficient rice; however, the crosstalk between them remains unclear. In the present study using P-deficient 'Nipponbare' (Nip), root NO accumulation significantly increased after 1 h and reached a maximum at 3 h, while ethylene production significantly increased after 3 h and reached a maximum at 6 h, indicating NO responded more quickly than ethylene. Irrespective of P status, addition of the NO donor sodium nitroprusside (SNP) significantly increased while the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (c-PTIO) significantly decreased the production of ethylene, while neither the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) nor the ethylene inhibitor aminoethoxyvinylglycine (AVG) had any influence on NO accumulation, suggesting NO acted upstream of ethylene. Under P-deficient conditions, SNP and ACC alone significantly increased root soluble P content through increasing pectin content, and c-PTIO addition to the ACC treatment still showed the same tendency; however, AVG+SNP treatment had no effect, further indicating that ethylene was the downstream signal affecting pectin content. The expression of the phosphate transporter gene OsPT2 showed the same tendency as the NO-ethylene-pectin pathway. Taken together, we conclude that ethylene functions downstream of NO in cell wall P reutilization in P-deficient rice. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.