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Sample records for rice plants exposed

  1. Shaping a better rice plant.

    PubMed

    Springer, Nathan

    2010-06-01

    Two studies describe how regulatory variation at the rice gene OsSPL14 can lead to altered plant morphology and improve grain yield. These studies support the possibility of improving rice yield through changing plant architecture.

  2. Effects on growth and oxidative stress status of rice plants (Oryza sativa) exposed to two extracts of toxin-producing cyanobacteria (Aphanizomenon ovalisporum and Microcystis aeruginosa).

    PubMed

    Prieto, Ana; Campos, Alexandre; Cameán, Ana; Vasconcelos, Vitor

    2011-10-01

    Toxic cyanobacteria are considered emerging world threats, being responsible for the degradation of the aquatic ecosystems. Aphanizomenon ovalisporum produces the toxin Cylindrospermopsin (CYN) being a concern in fresh water habitats. This work aims to increase our knowledge on the effects of this toxic cyanobacterium in plants by studying the alterations in growth parameters and oxidative stress status of rice (Oriza sativa) exposed to the cyanobacteria cell extracts containing CYN. Significant increases in glutathione S-transferase (GST) and glutathione peroxidase (GPx) activities were detected in the different experiments performed. The roots showed to be more sensitive than leaves regarding the enzyme activities. A reduction in the leaf tissue fresh weight was observed after 9 days of plant treatment suggesting a major physiological stress. The exposure of rice plants to a mixture of A. ovalisporum and Microcystis aeruginosa cell extracts containing CYN and microcystins including microcystin-LR, resulted in a significant increase in the GST and GPx activities, suggesting a synergistic effect of both extracts. Together these results point out the negative effects of cyanotoxins on plant growth and oxidative status, induced by A. ovalisporum cell extracts, raising also concerns in the accumulation of CYN. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. 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.

  4. Evidences for structural basis of altered ascorbate peroxidase activity in cadmium-stressed rice plants exposed to jasmonate.

    PubMed

    Singh, Indra; Shah, Kavita

    2014-04-01

    Binding interactions of cadmium (Cd) with rice ascorbate peroxidase (OsAPX) in presence or absence of jasmonate was examined in-silico. OsAPX is a 250 amino acid long protein with 90 % sequence similarity to soybean-APX. The 3D model of OsAPX obtained by homology modeling using soybean APX (PDBID:1OAF) as template was associated with -15975.85 kJ/mol energy, 100 % residues in favoured region, verify score of 0.85, ERRAT score 89.625 and a negative ProSA graph, suggesting OsAPX model to be of good quality, robust and reliable which was submitted with Protein Model Database with PMDBID: PM0078091. The rice ascorbate peroxidase ascorbate [OsAPX-Asc] complex had a substrate binding cavity involving residues at position (30)KSCAPL(35), (167)RCH(169) and (172)R wherein ascorbate accommodated via three H-bonds involving (30)Lys at the γ-edge of heme. (169)His served as a bridge between heme-porphyrin of OsAPX and ascorbate creating a charge relay system. Cd bound in [OsAPX-Asc-Cd] complex at (29)EKSCAPL(35), a site similar to ascorbate binding site. The binding of Cd caused breaking of (169)His bridge shifting the protein conformation. Cadmium exhibited four electrostatic interactions via (29)Glu of OsAPX backbone. Docking of [OsAPX-Asc] with jasmonic acid (JA) resulted in [OsAPX-Asc-JA] complex where 4-H-bonds held JA to OsAPX in a cavity at γ-edge on the distal side of heme. The binding of [OsAPX-Asc-JA] to Cd show the metal to bind at a position other than that involved in binding of OsAPX with Cd alone. Results indicate that Cd does not replace iron or ascorbate or JA but binds to OsAPX on the surface at a separate site electrostatically. In presence of JA the interactions involved in formation of [OsAPXAsc] are restored which is otherwise altered by the presence of Cd. The formation and reformation of H-bond take place between the [OsAPX-Asc] and Cd/JA. It is the interaction between heme and ascorbate which is modulated differently in presence of Cd/JA. In absence

  5. 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.

  6. Rice plant development: from zygote to spikelet.

    PubMed

    Itoh, Jun-Ichi; Nonomura, Ken-Ichi; Ikeda, Kyoko; Yamaki, Shinichiro; Inukai, Yoshiaki; Yamagishi, Hiroshi; Kitano, Hidemi; Nagato, Yasuo

    2005-01-01

    Rice is becoming a model plant in monocotyledons and a model cereal crop. For better understanding of the rice plant, it is essential to elucidate the developmental programs of the life cycle. To date, several attempts have been made in rice to categorize the developmental processes of some organs into substages. These studies are based exclusively on the morphological and anatomical viewpoints. Recent advancement in genetics and molecular biology has given us new aspects of developmental processes. In this review, we first describe the phasic development of the rice plant, and then describe in detail the developmental courses of major organs, leaf, root and spikelet, and specific organs/tissues. Also, for the facility of future studies, we propose a staging system for each organ.

  7. [Interference of allelopathic rice cultivars on barnyardgrass under different water irrigation and rice plant density].

    PubMed

    Xu, Zhenghao; He, Yong; Wang, Yiping; Yu, Gusong

    2004-09-01

    Pot culture experiments were conducted to examine the effects of water irrigation and rice plant density on the interference of allelopathic rice on barnyardgrass (Echinochloa crus-galli). The results showed that under water irrigations, allelopathic rice cultivars Xiayitiao, Gumei 2 and Zhong 156 significantly reduced the plant height of barnyardgrass than non-allelopathic rice cultivars Xiushui 63 and Chunjiang 11. Barnyardgrass plants grew shorter as rice plant density increased. Allelopathic rice cultivars Jizaoxian and Gumei 2 interfered with barnyardgrass, even at their densities as low as 4 plants per pot, and the interference reduced plant height of barnyardgrass significantly compared with the non-rice control. Allelopathic rice cultivars Xiayitiao, Jizaoxian, PI312777, TN1, Gumei 2 and Zhong 156 at 32 rice plants per pot inhibited the growth of barnyardgrass significantly than Chunjiang 11.

  8. DNA-protein cross-links involved in growth inhibition of rice seedlings exposed to Ga.

    PubMed

    Yu, Xiao-Zhang; Zhang, Xue-Hong

    2015-07-01

    Hydroponic experiments were conducted with rice seedlings (Oryza sativa L. cv. XZX45) exposed to gallium nitrate (Ga(3+)) to investigate the accumulation of Ga in plant tissues and phytotoxic responses. Results showed that phyto-transport of Ga was apparent, and roots were the dominant site for Ga accumulation. The total accumulation rates of Ga responded biphasically to Ga treatments by showing increases at low (1.06-8.52 mg Ga/L) and constants at high (8.52-15.63 mg Ga/L) concentrations, suggesting that accumulation kinetics of Ga followed a typical saturation curve. Higher amount of Ga accumulation in plant tissues led to significant inhibition in relative growth rate and water use efficiency in a dose-dependent manner. DNA-protein cross-links (DPCs) analysis revealed that overaccumulation of Ga in plant tissues positively stimulated formation of DPCs in roots. Likewise, the measure of root cell viability evaluated by Evan blue uptake showed a similar trend. These results suggested that Ga can be absorbed, transported, and accumulated in plant materials of rice seedlings. Overaccumulation of Ga in plant tissues provoked the formation of DPCs in roots, which resulted in cell death and growth inhibition of rice seedlings.

  9. A collection of glycosyltransferases from rice (Oryza sativa) exposed to atrazine.

    PubMed

    Lu, Yi Chen; Yang, Sheng Ning; Zhang, Jing Jing; Zhang, Jia Jun; Tan, Li Rong; Yang, Hong

    2013-12-01

    The rice (Oryza sativa) GTs belong to a super family possibly with hundreds of members. However, which GTs are involved in plant response to toxic chemicals is unknown. Here, we demonstrated 59 novel GT genes screened from our recent genome-wide sequencing datasets of rice crops exposed to atrazine (a herbicide persistent in ecosystems). Analysis of GT genes showed that most of the GTs contain functional domains typically found in proteins transferring glycosyl moieties to their target compounds. A phylogenetic analysis revealed that many GT genes from different families have diverse cis-elements necessary for response to biotic and environmental stresses. Experimental validation for the GTs was undertaken through a microarray, and 36 GT genes were significantly detected with an expression pattern similar to that from deep-sequencing datasets. Furthermore, 12 GT genes were randomly selected and confirmed by quantitative real-time RT-PCR. Finally, the special activity of total GTs was determined in rice roots and shoots, with an increased activity under the atrazine exposure. This response was closely associated with atrazine absorption in the rice tissues. These results indicate that exposure to atrazine can trigger specific GT genes and enzyme activities in rice.

  10. Epigenetic inheritance in rice plants.

    PubMed

    Akimoto, Keiko; Katakami, Hatsue; Kim, Hyun-Jung; Ogawa, Emiko; Sano, Cecile M; Wada, Yuko; Sano, Hiroshi

    2007-08-01

    Epigenetics is defined as mechanisms that regulate gene expression without base sequence alteration. One molecular basis is considered to be DNA cytosine methylation, which reversibly modifies DNA or chromatin structures. Although its correlation with epigenetic inheritance over generations has been circumstantially shown, evidence at the gene level has been limited. The present study aims to find genes whose methylation status directly correlates with inheritance of phenotypic changes. DNA methylation in vivo was artificially reduced by treating rice (Oryza sativa ssp. japonica) seeds with 5-azadeoxycytidine, and the progeny were cultivated in the field for > 10 years. Genomic regions with changed methylation status were screened by the methylation-sensitive amplified polymorphysm (MSAP) method, and cytosine methylation was directly scanned by the bisulfite mapping method. Pathogen infection with Xanthomonas oryzae pv. oryzae, race PR2 was performed by the scissors-dip method on mature leaf blades. The majority of seedlings were lethal, but some survived to maturity. One line designated as Line-2 showed a clear marker phenotype of dwarfism, which was stably inherited by the progeny over nine generations. MSAP screening identified six fragments, among which two were further characterized by DNA blot hybridization and direct methylation mapping. One clone encoding a retrotransposon gag-pol polyprotein showed a complete erasure of 5-methylcytosines in Line-2, but neither translocation nor expression of this region was detectable. The other clone encoded an Xa21-like protein, Xa21G. In wild-type plants, all cytosines were methylated within the promoter region, whereas in Line-2, corresponding methylation was completely erased throughout generations. Expression of Xa21G was not detectable in wild type but was constitutive in Line-2. When infected with X. oryzae pv. oryzae, against which Xa21 confers resistance in a gene-for-gene manner, the progeny of Line-2 were

  11. 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...

  12. Volatiles induction in rice stink bug host grasses and rice plants

    USDA-ARS?s Scientific Manuscript database

    Rice stink bug (RSB), Oebalus pugnax F., is an important pest of heading rice in the United States. Little is known about plant volatiles production following herbivory by the rice stink bug. RSB feeding induced volatiles production in different RSB host grasses and rice varieties, and may help expl...

  13. [Effects of rice plants on methane emission from paddy fields].

    PubMed

    Jia, Zhongjun; Cai, Zucong

    2003-11-01

    Methane emission from rice paddy fields is the net result of the combination of many processes, i.e., CH4 production, CH4 oxidation and CH4 transportation in paddy soil. Rice plants play a key role in the CH4 emission from paddy fields, particularly in all the processes involved. The positive and negative effects of rice plants on CH4 emission from paddy fields are well recognized as the main factors influencing the temporal variation of CH4 emission flux in paddy field. Process-based studies about the effects of rice plants on methane emission from paddy fields were summarized, and different roles of rice plants on this emission were discussed. Root exudates and litters of rice plants could serve as the substrate for methanogenesis and enhance the CH4 production of paddy soils, resulting in a high CH4 emission peak, particularly in rice late growing season. Rhizospheric CH4 oxidation induced by rice root-excreted oxygen constitutes a main biogenic sink of CH4, which could account for 36-90% of CH4 produced in paddy soil over the entire growing season of rice. Up to 80% and more of CH4 released from rice field during a growing season could be emitted by rice plant-mediated transport. The fully developed aerenchyma of rice plants could be of importance in CH4 emission during rice growing seasons, and responsible for the CH4 emission peak observed at rice early growing season.

  14. Red rice (Oryza sativa L.) emergence characteristics and influence on rice (O. sativa) yield at different planting dates

    USDA-ARS?s Scientific Manuscript database

    Cultivated rice yield losses due to red rice infestation vary by cultivar, red rice density, and duration of interference. The competition effects of red rice could be influenced further by emergence characteristics, red rice biotype, and planting time of cultivated rice. We aimed to characterize th...

  15. 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.

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

    PubMed Central

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

    2016-01-01

    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. PMID:27185548

  17. Comparative proteomic analysis of rice shoots exposed to high arsenate.

    PubMed

    Liu, Yanli; Li, Ming; Han, Chao; Wu, Fengxia; Tu, Bingkun; Yang, Pingfang

    2013-10-01

    Consumption of arsenic contaminated water and cereals is a serious threat to humans all over the world. Rice (Oryza sativa "Nipponbare"), as a main cereal crop, can accumulate arsenic more than 10-fold that of in other cereals. To gain a comprehensive understanding of the response of rice subjected to 100 µM arsenate stress, a comparative proteomic analysis of rice shoots in combination with morphological and biochemical investigations have been performed in this study. The results demonstrated that arsenate suppressed the growth of rice seedlings, destroyed the cellular ultra-structure and changed the homeostasis of reactive oxygen species. Moreover, a total of 38 differentially displayed proteins, which were mainly involved in metabolism, redox and protein-metabolism, were identified. The data suggest the arsenic can inhibit rice growth through negatively affecting chloroplast structure and photosynthesis. In addition, upregulation of the proteins involved in redox and protein metabolism might help the rice to be resistant or tolerant to arsenic toxicity. In general, this study improves our understanding about the rice arsenic responsive mechanism.

  18. Infection of rice plants by rice black streaked dwarf virus improves an egg parasitoid, Anagrus nilaparvatae (Hymenoptera: Mymaridae), of rice planthoppers.

    PubMed

    Xu, Hongxing; He, Xiaochan; Zheng, Xusong; Yang, Yajun; Tian, Junce; Lu, Zhongxian

    2014-10-01

    The effects of rice plants infected by rice black streaked dwarf virus (RBSDV) on the host preference, duration of immature stages, sex ratio, and adult longevity and parasitic capacity of an egg parasitoid, Anagrus nilaparvatae Pang et Wang, of rice brown planthopper, Nilaparvata lugens Stål, were evaluated. Tests of response to plant volatiles using an olfactometer showed that A. nilaparvatae preferred rice plants harboring rice brown planthopper eggs over plants free of rice brown planthopper eggs. However, both the response to plant volatiles and the host selectivity test showed no significant differences in host preference between RBSDV-infected plants and healthy plants when both contained rice brown planthopper eggs. The developmental duration at immature stage of the male A. nilaparvatae in rice brown planthopper eggs on RBSDV-infected rice plants was significantly prolonged, and the parasitic capacity of rice brown planthopper eggs was significantly increased in comparison with the A. nilaparvatae parasite in rice brown planthopper eggs on healthy rice plants. There were no significant differences between RBSDV-infected rice plants and healthy rice plants in other ecological fitness parameters, including the developmental duration of female adults, female percentage, and adult longevity of A. nilaparvatae.

  19. Creation of transgenic rice plants producing small interfering RNA of Rice tungro spherical virus.

    PubMed

    Le, Dung Tien; Chu, Ha Duc; Sasaya, Takahide

    2015-01-01

    Rice tungro spherical virus (RTSV), also known as Rice waika virus, does not cause visible symptoms in infected rice plants. However, the virus plays a critical role in spreading Rice tungro bacilliform virus (RTBV), which is the major cause of severe symptoms of rice tungro disease. Recent studies showed that RNA interference (RNAi) can be used to develop virus-resistance transgenic rice plants. In this report, we presented simple procedures and protocols needed for the creation of transgenic rice plants capable of producing small interfering RNA specific against RTSV sequences. Notably, our study showed that 60 out of 64 individual hygromycin-resistant lines (putative transgenic lines) obtained through transformation carried transgenes designed for producing hairpin double-stranded RNA. Northern blot analyses revealed the presence of small interfering RNA of 21- to 24-mer in 46 out of 56 confirmed transgenic lines. Taken together, our study indicated that transgenic rice plants carrying an inverted repeat of 500-bp fragments encoding various proteins of RTSV can produce small interfering RNA from the hairpin RNA transcribed from that transgene. In light of recent studies with other viruses, it is possible that some of these transgenic rice lines might be resistant to RTSV.

  20. Roles of plant hormones and their interplay in rice immunity.

    PubMed

    Yang, Dong-Lei; Yang, Yinong; He, Zuhua

    2013-05-01

    Plant hormones have been extensively studied for their importance in innate immunity particularly in the dicotyledonous model plant Arabidopsis thaliana. However, only in the last decade, plant hormones were demonstrated to play conserved and divergent roles in fine-tuning immune in rice (Oryza sativa L.), a monocotyledonous model crop plant. Emerging evidence showed that salicylic acid (SA) plays a role in rice basal defense but is differentially required by rice pattern recognition receptor (PRR) and resistance (R) protein-mediated immunity, and its function is likely dependent on the signaling pathway rather than the change of endogenous levels. Jasmonate (JA) plays an important role in rice basal defense against bacterial and fungal infection and may be involved in the SA-mediated resistance. Ethylene (ET) can act as a positive or negative modulator of disease resistance, depending on the pathogen type and environmental conditions. Brassinosteroid (BR) signaling and abscisic acid (ABA) either promote or defend against infection of pathogens with distinct infection/colonization strategies. Auxin and gibberellin (GA) are generally thought of as negative regulators of innate immunity in rice. Moreover, GA interacts antagonistically with JA signaling in rice development and immunity through the DELLA protein as a master regulator of the two hormone pathways. In this review, we summarize the roles of plant hormones in rice immunity and discuss their interplay/crosstalk mechanisms and the complex regulatory network of plant hormone pathways in fine-tuning rice immunity and growth.

  1. 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: ...

  2. Teosinte Branched 1 modulates tillering in rice plants.

    PubMed

    Choi, Min-Seon; Woo, Mi-Ok; Koh, Eun-Byeol; Lee, Joohyun; Ham, Tae-Ho; Seo, Hak Soo; Koh, Hee-Jong

    2012-01-01

    Tillering is an important trait of cereal crops that optimizes plant architecture for maximum yield. Teosinte Branched 1 (TB1) is a negative regulator of lateral branching and an inducer of female inflorescence formation in Zea mays (maize). Recent studies indicate that TB1 homologs in Oryza sativa (rice), Sorghum bicolor and Arabidopsis thaliana act downstream of the auxin and MORE AUXILIARY GROWTH (MAX) pathways. However, the molecular mechanism by which rice produces tillers remains unknown. In this study, transgenic rice plants were produced that overexpress the maize TB1 (mTB1) or rice TB1 (OsTB1) genes and silence the OsTB1 gene through RNAi-mediated knockdown. Because lateral branching in rice is affected by the environmental conditions, the phenotypes of transgenic plants were observed in both the greenhouse and the paddy field. Compared to wild-type plants, the number of tillers and panicles was reduced and increased in overexpressed and RNAi-mediated knockdown OsTB1 rice plants, respectively, under both environmental conditions. However, the effect was small for plants grown in paddy fields. These results demonstrate that both mTB1 and OsTB1 moderately regulate the tiller development in rice.

  3. [Climatic suitability of single cropping rice planting region in China].

    PubMed

    Duan, Ju-Qi; Zhou, Guang-Sheng

    2012-02-01

    To clarify the leading climate factors affecting the distribution of single cropping rice planting region in China at national and annual temporal scales and to reveal the potential distribution and climatic suitability divisions of this planting region in China could not only provide scientific basis for optimizing the allocation of single cropping rice production, modifying planting pattern, and introducing fine varieties, but also ensure the food security of China. In this paper, the potential climate factors affecting the single cropping rice distribution in China at regional and annual scales were selected from related literatures, and the single cropping rice geographic information from the national agro-meteorological observation stations of China Meteorological Administration (CMA), together with the maximum entropy model (MaxEnt) and spatial analyst function of Arc-GIS software, were adopted to clarify the leading climate factors affecting the potential distribution of single cropping rice planting region in China, and to construct a model about the relationships between the potential distribution of the planting region and the climate. The results showed that annual precipitation, moisture index, and days of not less than 18 degrees C stably were the leading climate factors affecting the potential distribution of single cropping rice planting region in China, with their cumulative contribution rate reached 94.5% of all candidate climate factors. The model constructed in this paper could well simulate the potential distribution of single cropping rice planting region in China. According to the appearance frequency, the low, medium and high climatic suitability divisions of single cropping rice planting region in China were clarified, and the climate characteristics of the planting region in each climatic suitability division were analyzed.

  4. 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

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

    USDA-ARS?s Scientific Manuscript database

    Pathogenic infection on plants may affect interactions of the 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, in rice plant...

  6. Phenotypical, physiological and biochemical analyses provide insight into selenium-induced phytotoxicity in rice plants.

    PubMed

    Mostofa, Mohammad Golam; Hossain, Mohammad Anwar; Siddiqui, Md Nurealam; Fujita, Masayuki; Tran, Lam-Son Phan

    2017-03-11

    The present study investigated the phenotypical, physiological and biochemical changes of rice plants exposed to high selenium (Se) concentrations to gain an insight into Se-induced phytotoxicity. Results showed that exposure of rice plants to excessive Se resulted in growth retardation and biomass reduction in connection with the decreased levels of chlorophyll, carotenoids and soluble proteins. The reduced water status and an associated increase in sugar and proline levels indicated Se-induced osmotic stress in rice plants. Measurements of Se contents in roots, leaf sheaths and leaves revealed that Se was highly accumulated in leaves followed by leaf sheaths and roots. Se also potentiated its toxicity by impairing oxidative metabolism, as evidenced by enhanced accumulation of hydrogen peroxide, superoxide and lipid peroxidation product. Se toxicity also displayed a desynchronized antioxidant system by elevating the level of glutathione and the activities of superoxide dismutase, glutathione-S-transferase and glutathione peroxidase, whereas decreasing the level of ascorbic acid and the activities of catalase, glutathione reductase and dehydroascorbate reductase. Furthermore, Se triggered methylglyoxal toxicity by inhibiting the activities of glyoxalases I and II, particularly at higher concentrations of Se. Collectively, our results suggest that excessive Se caused phytotoxic effects on rice plants by inducing chlorosis, reducing sugar, protein and antioxidant contents, and exacerbating oxidative stress and methylglyoxal toxicity. Accumulation levels of Se, proline and glutathione could be considered as efficient biomarkers to indicate degrees of Se-induced phytotoxicity in rice, and perhaps in other crops.

  7. Carbofuran promotes biochemical changes in carp exposed to rice field and laboratory conditions.

    PubMed

    Clasen, Bárbara; Leitemperger, Jossiele; Murussi, Camila; Pretto, Alexandra; Menezes, Charlene; Dalabona, Fabrícia; Marchezan, Enio; Adaime, Martha Bohrer; Zanella, Renato; Loro, Vania Lucia

    2014-03-01

    Effects of carbofuran commercial formulation on oxidative stress parameters were studied in carps (Cyprinus carpio) exposed to 50µg/L for 7 and 30 days under rice field and laboratory conditions. Thiobarbituric acid reactive substance (TBARS) levels were increased in the brain of fish after 7 and 30 days under rice field and laboratory conditions. In the liver and muscle, TBARS levels increased after 7 and 30 days under laboratory conditions, whereas in rice field the levels increased only after 30 days. Protein carbonyl content in the liver increased after 7 and 30 days under both experimental conditions. Acetylcholinesterase (AChE) activity was decreased in the brain and muscle after 7 and 30 days under both experimental conditions evaluated. The superoxide dismutase (SOD) activity increased in the liver after 7 and 30 days under rice field condition, whereas under laboratory condition this enzyme increased only after 30 days. The catalase (CAT) activity in the liver decreased after 30 days under rice field condition, whereas no changes were observed under laboratory conditions. In rice field, glutathione S-transferase (GST) decreased after 7 days but increased after 30 days, whereas no change was observed in fish exposed to carbofuran under laboratory conditions. These results suggest that environmental relevant carbofuran concentrations may cause oxidative stress, affecting biochemical and enzymatic parameters on carps. Some parameters could be used as biomarkers to carbofuran exposure. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. Dissipation and residues of monosultap in rice plant and environment.

    PubMed

    Zhang, Fengzu; Wang, Lei; Zhou, Li; Pan, Canping

    2012-03-01

    A modified method for the analysis of monosultap residue in rice plant and environment was developed and validated. Monosultap residue dynamics and final residues in supervised field trials at GAP conditions were studied. At fortification levels of 0.05, 0.5 and 1 mg kg(-1), it was shown that recoveries ranged from 75.0% to 109.2% with RSDs of 1.2-5.1% (n = 5). The dissipation experiments showed the half-lives (T(1/2)) of monosultap in water, soil and rice plants were 1.1-1.9, 1.4-2.1 and 1.3-2.1 days, respectively. At pre-harvest intervals (PHI) of 21 and 30 days, monosultap residue were 0.01-0.06 mg kg(-1) in soil, 0.01-0.19 mg kg(-1) in rice plants, and 0.01-0.09 mg kg(-1) in husked rice.

  9. 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.

  10. 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.

  11. 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

  12. Phytoremediation of metolachlor by transgenic rice plants expressing human CYP2B6.

    PubMed

    Kawahigashi, Hiroyuki; Hirose, Sakiko; Ohkawa, Hideo; Ohkawa, Yasunobu

    2005-11-16

    We introduced the human cytochrome P450 gene CYP2B6 into rice plants (Oryza sativa L. cv. Nipponbare), and the CYP2B6-expressing rice plants became more tolerant to various herbicides than nontransgenic Nipponbare rice plants. In particular, CYP2B6 rice plants grown in soil showed tolerance to the chloroacetanilide herbicides alachlor and metolachlor. We evaluated the degradation of metolachlor by CYP2B6 rice plants to confirm the metabolic activity of the introduced CYP2B6. Although both CYP2B6 and nontransgenic Nipponbare rice plants could decrease the amount of metolachlor in plant tissue and culture medium, CYP2B6 rice plants could remove much greater amounts. In a greenhouse, the ability of CYP2B6 rice plants to remove metolachlor was confirmed in large-scale experiments, in which these plants appeared able to decrease residual quantities of metolachlor in water and soil.

  13. Proteomic analysis of upland rice (Oryza sativa L.) exposed to intermittent water deficit.

    PubMed

    Rabello, Fernanda R; Villeth, Gabriela R C; Rabello, Aline R; Rangel, Paulo H N; Guimarães, Cleber M; Huergo, Luciano F; Souza, Emanuel M; Pedrosa, Fabio O; Ferreira, Márcio E; Mehta, Angela

    2014-06-01

    Rice is the most important crop consumed all over the world. In Brazil, irrigated rice covers 50 % of the rice producing area and is responsible for 75 % of the national production. Upland rice covers most of the remaining area, and is therefore, a very important production system in the country. In the present study, we have used the drought tolerant upland rice variety Três Meses Antigo to investigate the proteomic changes that occur during drought stress. Plants were submitted to drought by the reposition of 50 % of the water lost daily. Twenty days after the beginning of the drought stress period, leaves were harvested and used for protein extraction. The 2D maps obtained from treated and control plants revealed 408 reproducible spots, 44 of which were identified by mass spectrometry, including 15 differential proteins. Several unaltered proteins were also identified (39 spots) and were mainly involved in photosynthesis. Taken together, the results obtained suggest that the tolerant upland rice up-regulates anti-oxidant and energy production related proteins in order to cope with water deficit.

  14. 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

  15. 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 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.

  16. Differences in how rice plants processes arsenic in their cells

    USDA-ARS?s Scientific Manuscript database

    Arsenic (As), a carcinogenic heavy metal, is a problem in some drinking water and staple food supplies around the world. Rice plants readily uptake arsenic and transport a portion of it into the grain. Arsenic is also toxic to plants; therefore mechanisms that reduce toxicity or accumulation have ev...

  17. [Obtaining transgenic rice plants and their progenies using Agrobacterium tumefaciens].

    PubMed

    Yin, Z C; Yang, F; Xu, Y; Li, B J

    1998-12-01

    Rice (Oriza sativa L.) suspension cells of Taipei 309 were co-cultivated with A. tumefaciens stran EHA101 harbouring binary vector pBYT2 for 3 days in the presence of vir inducer, 100 mumol/L acetosyringone (AS). After 2 months of continuous selection, 17 stable hygromycin-resistant, GUS-positive calli were recovered from 364 suspension cell clusters co-cultivated with A. tumefaciens. 10 putative transgenic R0 plants obtained from 8 tansformed calli and their progenies were analyzed for the integration and expression of foreign genes. Southern blot analysis of R0 and R1 generations indicated that foreign genes had been stably integrated in the genome of transgenic rice and sexually transmitted. One of the transgenic lines showed 5 copies of T-DNA integration, while the others had only one copy. Histochemical staining observation and fluorometric assay of GUS activity in transgenic rice cells and plants showed ubiquitin promoter from maize was highly effective in driving the expression of gus reporter gene in transgenic rice cells. GUS protein and its activity were also investigated through ndPAGE-X-Gluc staining assay, and it was found that the GUS protein in transgenic rice cells was smaller in size than the standard GUS protein (Sigma Co. G0786) but as large as that from E.coli HB101 (pBI121). This study suggested that Agrobacterium-mediated transformation of plant is an efficient and reliable method to introduce foreign genes into rice.

  18. Transcriptomics exposes the uniqueness of parasitic plants.

    PubMed

    Ichihashi, Yasunori; Mutuku, J Musembi; Yoshida, Satoko; Shirasu, Ken

    2015-07-01

    Parasitic plants have the ability to obtain nutrients directly from other plants, and several species are serious biological threats to agriculture by parasitizing crops of high economic importance. The uniqueness of parasitic plants is characterized by the presence of a multicellular organ called a haustorium, which facilitates plant-plant interactions, and shutting down or reducing their own photosynthesis. Current technical advances in next-generation sequencing and bioinformatics have allowed us to dissect the molecular mechanisms behind the uniqueness of parasitic plants at the genome-wide level. In this review, we summarize recent key findings mainly in transcriptomics that will give us insights into the future direction of parasitic plant research.

  19. Molecular analysis of rice plant mutated after space flight

    NASA Astrophysics Data System (ADS)

    Cheng, Z.; Li, C.; Wei, L.; Xu, D.; Gu, D.; Guan, S.; Zhao, H.; Xin, P.; Sun, Y.

    We have obtained several rice mutants planted from seeds flown on recoverable satellites. Some new traits, such as good yields, diseases resistances and higher nutrient values, have been identified, putatively as consequences of the space environment. Radiation inside the Chinese recoverable satellite was composed of low flux of high energy particles (>40 Mev/u). To study the mechanisms of plant mutations induced by the space environment, we used dry rice seeds as a model to identify the phenotype of mutations, and used the wealth of the rice genome to identify the mutated genes in the mutants. The research included collecting rice plant mutants in the seeds flown on the satellites, identifying the nature of genomic and proteomic alterations, modifications and identifying the functional changes of the specific genes. The study showed that the rice seeds are a good model for exploring biological effect of space environment since 1) it is easy fly the seeds without specific hardware and crew work, 2) it is easy to obtain pure mutant breed lines for cloning DNA sequence in order to compare with the sequence in the wild type, and 3) it is easy to quantitatively analyze genetics using advanced molecular techniques.

  20. Transgenic rice plants expressing synthetic cry2AX1 gene exhibits resistance to rice leaffolder (Cnaphalocrosis medinalis).

    PubMed

    Manikandan, R; Balakrishnan, N; Sudhakar, D; Udayasuriyan, V

    2016-06-01

    Bacillus thuringiensis is a major source of insecticidal genes imparting insect resistance in transgenic plants. Level of expression of transgenes in transgenic plants is important to achieve desirable level of resistance against target insects. In order to achieve desirable level of expression, rice chloroplast transit peptide sequence was fused with synthetic cry2AX1 gene to target its protein in chloroplasts. Sixteen PCR positive lines of rice were generated by Agrobacterium mediated transformation using immature embryos. Southern blot hybridization analysis of T0 transgenic plants confirmed the integration of cry2AX1 gene in two to five locations of rice genome and ELISA demonstrated its expression. Concentration of Cry2AX1 in transgenic rice events ranged 5.0-120 ng/g of fresh leaf tissue. Insect bioassay of T0 transgenic rice plants against neonate larvae of rice leaffolder showed larval mortality ranging between 20 and 80 % in comparison to control plant. Stable inheritance and expression of cry2AX1 gene was demonstrated in T1 progenies through Southern and ELISA. In T1 progenies, the highest concentration of Cry2AX1 and mortality of rice leaffolder larvae were recorded as 150 ng/g of fresh leaf tissue and 80 %, respectively. The Cry2AX1 expression even at a very low concentration (120-150 ng/g) in transgenic rice plants was found effective against rice leaffolder larvae.

  1. Plant phosphomannose isomerase as a selectable marker for rice transformation

    PubMed Central

    Hu, Lei; Li, Hao; Qin, Ruiying; Xu, Rongfang; Li, Juan; Li, Li; Wei, Pengcheng; Yang, Jianbo

    2016-01-01

    The E. coli phosphomannose isomerase (EcPMI) gene is widely used as a selectable marker gene (SMG) in mannose (Man) selection-based plant transformation. Although some plant species exhibit significant PMI activity and active PMIs were even identified in Man-sensitive plants, whether plant PMIs can be used as SMGs remains unclear. In this study, we isolated four novel PMI genes from Chlorella variabilis and Oryza sativa. Their isoenzymatic activities were examined in vitro and compared with that of EcPMI. The active plant PMIs were separately constructed into binary vectors as SMGs and then transformed into rice via Agrobacterium. In both Indica and Japonica subspecies, our results indicated that the plant PMIs could select and produce transgenic plants in a pattern similar to that of EcPMI. The transgenic plants exhibited an accumulation of plant PMI transcripts and enhancement of the in vivo PMI activity. Furthermore, a gene of interest was successfully transformed into rice using the plant PMIs as SMGs. Thus, novel SMGs for Man selection were isolated from plants, and our analysis suggested that PMIs encoding active enzymes might be common in plants and could potentially be used as appropriate genetic elements in cisgenesis engineering. PMID:27174847

  2. Photosynthesis is induced in rice plants that associate with arbuscular mycorrhizal fungi and are grown under arsenate and arsenite stress.

    PubMed

    de Andrade, Sara Adrian Lopez; Domingues, Adilson Pereira; Mazzafera, Paulo

    2015-09-01

    The metalloid arsenic (As) increases in agricultural soils because of anthropogenic activities and may have phytotoxic effects depending on the available concentrations. Plant performance can be improved by arbuscular mycorrhiza (AM) association under challenging conditions, such as those caused by excessive soil As levels. In this study, the influence of AM on CO2 assimilation, chlorophyll a fluorescence, SPAD-chlorophyll contents and plant growth was investigated in rice plants exposed to arsenate (AsV) or arsenite (AsIII) and inoculated or not with Rhizophagus irregularis. Under AsV and AsIII exposure, AM rice plants had greater biomass accumulation and relative chlorophyll content, increased water-use efficiency, higher carbon assimilation rate and higher stomatal conductance and transpiration rates than non-AM rice plants did. Chlorophyll a fluorescence analysis revealed significant differences in the response of AM-associated and -non-associated plants to As. Mycorrhization increased the maximum and actual quantum yields of photosystem II and the electron transport rate, maintaining higher values even under As exposure. Apart from the negative effects of AsV and AsIII on the photosynthetic rates and PSII efficiency in rice leaves, taken together, these results indicate that AM is able to sustain higher rice photosynthesis efficiency even under elevated As concentrations, especially when As is present as AsV. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Multiple Method Analysis of TiO2 Nanoparticle Uptake in Rice (Oryza sativa L.) Plants.

    PubMed

    Deng, Yingqing; Petersen, Elijah J; Challis, Katie E; Rabb, Savelas A; Holbrook, R David; Ranville, James F; Nelson, Bryant C; Xing, Baoshan

    2017-09-19

    Understanding the translocation of nanoparticles (NPs) into plants is challenging because qualitative and quantitative methods are still being developed and the comparability of results among different methods is unclear. In this study, uptake of titanium dioxide NPs and larger bulk particles (BPs) in rice plant (Oryza sativa L.) tissues was evaluated using three orthogonal techniques: electron microscopy, single-particle inductively coupled plasma mass spectroscopy (spICP-MS) with two different plant digestion approaches, and total elemental analysis using ICP optical emission spectroscopy. In agreement with electron microscopy results, total elemental analysis of plants exposed to TiO2 NPs and BPs at 5 and 50 mg/L concentrations revealed that TiO2 NPs penetrated into the plant root and resulted in Ti accumulation in above ground tissues at a higher level compared to BPs. spICP-MS analyses revealed that the size distributions of internalized particles differed between the NPs and BPs with the NPs showing a distribution with smaller particles. Acid digestion resulted in higher particle numbers and the detection of a broader range of particle sizes than the enzymatic digestion approach, highlighting the need for development of robust plant digestion procedures for NP analysis. Overall, there was agreement among the three techniques regarding NP and BP penetration into rice plant roots and spICP-MS showed its unique contribution to provide size distribution information.

  4. [Genetic ecology of rice allelopathy on receiver plant].

    PubMed

    He, Huaqin; Lin, Wenxiong; Dong, Zhanghang; Guo, Yuchun; Shen, Lihua; Liang, Yiyuan; Chen, Fangyu; Liang, Kangjing

    2002-12-01

    In this study, 5 parental rice lines with different allelopathic potential were employed in partial diallel cross (4 x 5) to get 10 groups of F1 seeds. After testing the inhibitory effects of 5 parents and 10 F1s under different environment at different leaf stage on the shoot length of receiver plant lettuce(Lactuca sativa L.), dynamic genetics of rice allelopathy and its genotype x environment effects were analyzed by using additive-dominant developmental genetic models. The results showed that additive and dominant effect genes expressed alternatively during 3-leaf stage to 8-leaf stage in rice seedling. As additive effect genes were pronounced at 7-leaf stage, dominant effect genes appeared to play the most important role at 3-leaf stage and 6-leaf stage but the two effect genes were equally important at 5-leaf stage and 8-leaf stage. Heritabilities analysis indicated that the general heritability in the narrow sense(HN2) was significant at 5-, 7- and 8-leaf stage, and decreased with increasing leaf stage. Rice allelopathy was significantly affected by genotype x environment (GE) interaction, suggesting that the environment of allelopathic rice development must be controlled for practical use.

  5. Biology of rice bug Leptocorisa oratorius (Fabricius) (Hemiptera: Alydidae), population change and alternative host plants.

    PubMed

    Rattanapun, W

    2013-01-01

    Leptocorisa oratorius (Fabricius) (Hemiptera: Alydidae) is a major rice pest which feeds on the sap of stems and rice seeds. Some graminaceous weed species serve as an alternative host of L. oratorius causing outbreaks throughout the rice growing season. Population changes of L. oratorius during both rice growing seasons - wet-season rice and dry-season rice - including the influence of alternative host, barnyard grass Echinochloa crus-galli (Graminaceae) on the development of L. oratorius was studied. Results presented that L. oratorius was the dominant pest species during the late phase of rice growth. Adults of L. oratorius started their migrations to wet-season rice at the vegetative stage of rice growth, while they migrated to dry-season rice at the repropuctive stage of rice growth. Leptocorisa oratorius breds rapidly in rice fields. Meanwhile, other adults migrated to the rice field. The population of adults and nymphs significantly increased from the reproductive stage to grain formation and ripening stage in both rice growing seasons. The population of nymphs was greater than adults but not significantly different in their number of individuals. Leptocorisa oratorius had one generation in each rice growing season. The results of the host plant study indicated that L oratorius developed completely in barnyard grass E. crus-galli as well as rice Oriza sativa (Graminaceae). However, L. oratorius preferred rice to barnyard grass for feeding and oviposition.

  6. Modeling the leaf angle dynamics in rice plant

    PubMed Central

    Zhang, Yonghui; Tang, Liang; Liu, Xiaojun; Liu, Leilei; Cao, Weixing; Zhu, Yan

    2017-01-01

    The leaf angle between stem and sheath (SSA) is an important rice morphological trait. The objective of this study was to develop and validate a dynamic SSA model under different nitrogen (N) rates for selected rice cultivars. The time-course data of SSA were collected in three years, and a dynamic SSA model was developed for different main stem leaf ranks under different N rates for two selected rice cultivars. SSA increased with tiller age. The SSA of the same leaf rank increased with increase in N rate. The maximum SSA increased with leaf rank from the first to the third leaf, then decreased from the third to the final leaf. The relationship between the maximum SSA and leaf rank on main stem could be described with a linear piecewise function. The change of SSA with thermal time (TT) was described by a logistic equation. A variety parameter (the maximum SSA of the 3rd leaf on main stem) and a nitrogen factor were introduced to quantify the effect of cultivar and N rate on SSA. The model was validated against data collected from both pot and field experiments. The relative root mean square error (RRMSE) was 11.56% and 14.05%, respectively. The resulting models could be used for virtual rice plant modeling and plant-type design. PMID:28207799

  7. Modeling the leaf angle dynamics in rice plant.

    PubMed

    Zhang, Yonghui; Tang, Liang; Liu, Xiaojun; Liu, Leilei; Cao, Weixing; Zhu, Yan

    2017-01-01

    The leaf angle between stem and sheath (SSA) is an important rice morphological trait. The objective of this study was to develop and validate a dynamic SSA model under different nitrogen (N) rates for selected rice cultivars. The time-course data of SSA were collected in three years, and a dynamic SSA model was developed for different main stem leaf ranks under different N rates for two selected rice cultivars. SSA increased with tiller age. The SSA of the same leaf rank increased with increase in N rate. The maximum SSA increased with leaf rank from the first to the third leaf, then decreased from the third to the final leaf. The relationship between the maximum SSA and leaf rank on main stem could be described with a linear piecewise function. The change of SSA with thermal time (TT) was described by a logistic equation. A variety parameter (the maximum SSA of the 3rd leaf on main stem) and a nitrogen factor were introduced to quantify the effect of cultivar and N rate on SSA. The model was validated against data collected from both pot and field experiments. The relative root mean square error (RRMSE) was 11.56% and 14.05%, respectively. The resulting models could be used for virtual rice plant modeling and plant-type design.

  8. 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

  9. STUDIES ON THE BACTERIAL LEAF BLIGHT OF RICE PLANT. ON THE DISTRIBUTION OF BACTERIUM ORYZAE (UEDA ET ISHIYAMA) NAKATA UPON THE RICE PLANTS (PRELIMINARY REPORT),

    DTIC Science & Technology

    The report contains a study of an outbreak of bacterial leaf blight of rice plants. An investigation of the primary source was made. Knowledge of the...distribution of infective agent on rice plants, when the primary infection occurs and before the appearance of the blight is recognized, was thought

  10. Autotoxicity mechanism of Oryza sativa: transcriptome response in rice roots exposed to ferulic acid

    PubMed Central

    2013-01-01

    Background Autotoxicity plays an important role in regulating crop yield and quality. To help characterize the autotoxicity mechanism of rice, we performed a large-scale, transcriptomic analysis of the rice root response to ferulic acid, an autotoxin from rice straw. Results Root growth rate was decreased and reactive oxygen species, calcium content and lipoxygenase activity were increased with increasing ferulic acid concentration in roots. Transcriptome analysis revealed more transcripts responsive to short ferulic-acid exposure (1- and 3-h treatments, 1,204 genes) than long exposure (24 h, 176 genes). Induced genes were involved in cell wall formation, chemical detoxification, secondary metabolism, signal transduction, and abiotic stress response. Genes associated with signaling and biosynthesis for ethylene and jasmonic acid were upregulated with ferulic acid. Ferulic acid upregulated ATP-binding cassette and amino acid/auxin permease transporters as well as genes encoding signaling components such as leucine-rich repeat VIII and receptor-like cytoplasmic kinases VII protein kinases, APETALA2/ethylene response factor, WRKY, MYB and Zinc-finger protein expressed in inflorescence meristem transcription factors. Conclusions The results of a transcriptome analysis suggest the molecular mechanisms of plants in response to FA, including toxicity, detoxicification and signaling machinery. FA may have a significant effect on inhibiting rice root elongation through modulating ET and JA hormone homeostasis. FA-induced gene expression of AAAP transporters may contribute to detoxicification of the autotoxin. Moreover, the WRKY and Myb TFs and LRR-VIII and SD-2b kinases might regulate downstream genes under FA stress but not general allelochemical stress. This comprehensive description of gene expression information could greatly facilitate our understanding of the mechanisms of autotoxicity in plants. PMID:23705659

  11. Enantioselective degradation of metalaxyl in grape, tomato, and rice plants.

    PubMed

    Wang, Meiyun; Hua, Xiude; Zhang, Qing; Yang, Yu; Shi, Haiyan; Wang, Minghua

    2015-02-01

    Enantioselective biodegradation of chiral pesticide metalaxyl in grape, tomato, and rice plants under field conditions were studied. Metalaxyl enantiomers were completely separated with a resolution (Rs) of 5.01 by high-performance liquid chromatography (HPLC) based on a cellulose tris (3-chloro-4-methyl phenyl carbamate) chiral column (Lux Cellulose-2). Metalaxyl enantiomers from matrixes were extracted by acetonitrile and purged using Cleanert Alumina-A solid phase extraction (SPE). The linearity, recovery, precision, sensitivity, and matrix effect of the method were assessed. The result showed that significant stereoselectivity occurred in grape, tomato, and rice plants. In grape, (+)-S-metalaxyl with a half-life of 5.5 d degraded faster than (-)-R-metalaxyl with that of 6.9 d, and the enantiomer fraction (EF) value reached 0.37 at 21 d. The same enantioselectivity was observed in tomato, and the half-life was 2.2 d for the S-enantiomer and 3.0 d for the R-enantiomer. The EF values decreased from 0.49 of 0 d to 0.26 of 14 d. On the other hand, a preferential degradation of the R-form was found in rice plants, with an EF value of 0.70 at 14 d, and the corresponding half-life was 2.3 d for the R-form and 2.8 d for the S-form. © 2014 Wiley Periodicals, Inc.

  12. 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.

  13. Accumulation of arsenic in tissues of rice plant (Oryza sativa L.) and its distribution in fractions of rice grain.

    PubMed

    Rahman, M Azizur; Hasegawa, H; Rahman, M Mahfuzur; Rahman, M Arifur; Miah, M A M

    2007-10-01

    A study was conducted to investigate the accumulation and distribution of arsenic in different fractions of rice grain (Oryza sativa L.) collected from arsenic affected area of Bangladesh. The agricultural soil of study area has become highly contaminated with arsenic due to the excessive use of arsenic-rich underground water (0.070+/-0.006 mg l(-1), n=6) for irrigation. Arsenic content in tissues of rice plant and in fractions of rice grain of two widely cultivated rice varieties, namely BRRI dhan28 and BRRI hybrid dhan1, were determined. Regardless of rice varieties, arsenic content was about 28- and 75-folds higher in root than that of shoot and raw rice grain, respectively. In fractions of parboiled and non-parboiled rice grain of both varieties, the order of arsenic concentrations was; rice hull>bran-polish>brown rice>raw rice>polish rice. Arsenic content was higher in non-parboiled rice grain than that of parboiled rice. Arsenic concentrations in parboiled and non-parboiled brown rice of BRRI dhan28 were 0.8+/-0.1 and 0.5+/-0.0 mg kg(-1) dry weight, respectively while those of BRRI hybrid dhan1 were 0.8+/-0.2 and 0.6+/-0.2 mg kg(-1) dry weight, respectively. However, parboiled and non-parboiled polish rice grain of BRRI dhan28 contained 0.4+/-0.0 and 0.3+/-0.1 mg kg(-1) dry weight of arsenic, respectively while those of BRRI hybrid dhan1 contained 0.43+/-0.01 and 0.5+/-0.0 mg kg(-1) dry weight, respectively. Both polish and brown rice are readily cooked for human consumption. The concentration of arsenic found in the present study is much lower than the permissible limit in rice (1.0 mg kg(-1)) according to WHO recommendation. Thus, rice grown in soils of Bangladesh contaminated with arsenic of 14.5+/-0.1 mg kg(-1) could be considered safe for human consumption.

  14. 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.

  15. [Temperature differences of air-rice plant under different irrigated water depths at spiking stage].

    PubMed

    Zhang, Bin; Zheng, Jian-chu; Huang, Shan; Tian, Yun-lu; Peng, Lan; Bian, Xin-min; Zhang, Wei-jian

    2008-01-01

    With rice cultivars Yangdao 6, Yangjing 9538 and Wuxiangjing 14 as test materials, field experiment was conducted to study the effects of 3 irrigated water depths (0 cm, 2-4 cm, and > 10 cm) on the temperature of different parts of rice plant at spiking stage. The results showed that from 10:30 to 15:00 on sunny days, irrigated water depth on paddy field had significant effects on the temperature of field surface, middle part of rice plant, and rice spike. The higher the water depth on field surface, the lower the temperature of rice plant and rice spike. At the water level > 10 cm, the average temperature differences between air and the rice spike, middle part of rice plant and field surface of these three cultivars were 1.37, 2.98 and 4.12 degrees C higher than those at the water depth of 0 cm, and 0.67, 1.59 and 2.17 degrees C higher than those at the water depth of 2-4 cm, respectively. In addition, the temperature differences were 0.71, 1.39 and 1.95 degrees C higher at the water depth of 2-4 cm than those at the water depth of 0 cm, respectively. Obvious temperature differences of air-rice plant were also observed among the three rice varieties under different irrigated water depths. The analysis of the characteristics of temperature transfer among field surface, middle part of plant and rice spike indicated that the temperature transfer patterns under all test water management regimes accorded with the principles of energy transfer, suggesting that keeping proper water depth on the field surface at rice spiking stage contributed great to the decrease of rice spike temperature and the alleviation of rice heat injury.

  16. Electrophysiological Responses of the Rice Leaffolder, Cnaphalocrocis medinalis, to Rice plant Volatiles

    PubMed Central

    Sun, Xiao; Liu, Zhuang; Zhang, Aijun; Dong, Hai-Bo; Zeng, Fang-Fang; Pan, Xiang-Yu; Wang, Yongmo; Wang, Man-Qun

    2014-01-01

    The rice leaffolder, Cnaphalocrocis medinalis Guenée (Lepidoptera: Pyralidae), is one of the most destructive pests of rice. Electrophysiological responses of this species to 38 synthetic volatiles known to be released from rice plants (Poaceae: Oryza spp.) were studied using the electroantennogram (EAG) method. Compounds that elicited the strongest EAG responses for each physiological condition were selected for EAG dose-response tests at five concentrations. These compounds included: methyl salicylate, heptanol, linalool, cyclohexanol, and 2-heptanone for one-day-old male moths; heptanol, hexanal, (Z)-2-hexen-1-ol, and nonadecane for one-dayold females; methyl salicylate, heptanol, (E)-2-hexen-1-ol, and (Z)-2-hexen-1-ol for three-dayold males; linalool, heptanol, (E)-2-hexen-1-ol, 2-heptanone, and hexanal for three-day-old females; 2-heptanone, cyclohexanol, linalool, heptanol, and methyl salicylate for five-day-old virgin females; and methyl benzoate, (Z)-2-hexen-1-ol, heptanol, linalool, and hexanal for fiveday- old mated females. Female and male C. medinalis exhibited broad overlap in their EAG responses, and there was no clear difference between male and female EAG responses to different compounds. Statistical analyses revealed that both volatile compound chemical structure and C. medinalis physiological condition (age, sex, and mating condition) had an effect on EAG response. PMID:25373217

  17. 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.

  18. 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. T2 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.

  19. Genetic evidence for natural product-mediated plant-plant allelopathy in rice (Oryza sativa).

    PubMed

    Xu, Meimei; Galhano, Rita; Wiemann, Philipp; Bueno, Emilio; Tiernan, Mollie; Wu, William; Chung, Ill-Min; Gershenzon, Jonathan; Tudzynski, Bettina; Sesma, Ane; Peters, Reuben J

    2012-02-01

    • There is controversy as to whether specific natural products play a role in directly mediating antagonistic plant-plant interactions - that is, allelopathy. If proved to exist, such phenomena would hold considerable promise for agronomic improvement of staple food crops such as rice (Oryza sativa). • However, while substantiated by the presence of phytotoxic compounds at potentially relevant concentrations, demonstrating a direct role for specific natural products in allelopathy has been difficult because of the chemical complexity of root and plant litter exudates. This complexity can be bypassed via selective genetic manipulation to ablate production of putative allelopathic compounds, but such an approach previously has not been applied. • The rice diterpenoid momilactones provide an example of natural products for which correlative biochemical evidence has been obtained for a role in allelopathy. Here, we apply reverse genetics, using knock-outs of the relevant diterpene synthases (copalyl diphosphate synthase 4 (OsCPS4) and kaurene synthase-like 4 (OsKSL4)), to demonstrate that rice momilactones are involved in allelopathy, including suppressing growth of the widespread rice paddy weed, barnyard grass (Echinochloa crus-galli). • Thus, our results not only provide novel genetic evidence for natural product-mediated allelopathy, but also furnish a molecular target for breeding and metabolic engineering of this important crop plant. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

  20. 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.

  1. Asymmetric Spread of SRBSDV between Rice and Corn Plants by the Vector Sogatella furcifera (Hemiptera: Delphacidae)

    PubMed Central

    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. PMID:27760223

  2. A built-in strategy for containment of transgenic plants: creation of selectively terminable transgenic rice.

    PubMed

    Lin, Chaoyang; Fang, Jun; Xu, Xiaoli; Zhao, Te; Cheng, Jiaan; Tu, Juming; Ye, Gongyin; Shen, Zhicheng

    2008-03-19

    Plant transgenic technology has been widely utilized for engineering crops for trait improvements and for production of high value proteins such as pharmaceuticals. However, the unintended spreading of commercial transgenic crops by pollination and seed dispersal is a major concern for environmental and food safety. Simple and reliable containment strategies for transgenes are highly desirable. Here we report a novel method for creating selectively terminable transgenic rice. In this method, the gene(s) of interest is tagged with a RNA interference cassette, which specifically suppresses the expression of the bentazon detoxification enzyme CYP81A6 and thus renders transgenic rice to be sensitive to bentazon, a herbicide used for rice weed control. We generated transgenic rice plants by this method using a new glyphosate resistant 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene from Pesudomonas putida as the gene of interest, and demonstrated that these transgenic rice plants were highly sensitive to bentazon but tolerant to glyphosate, which is exactly the opposite of conventional rice. Field trial of these transgenic rice plants further confirmed that they can be selectively killed at 100% by one spray of bentazon at a regular dose used for conventional rice weed control. Furthermore, we found that the terminable transgenic rice created in this study shows no difference in growth, development and yield compared to its non-transgenic control. Therefore, this method of creating transgenic rice constitutes a novel strategy of transgene containment, which appears simple, reliable and inexpensive for implementation.

  3. 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.

  4. Plant growth-promoting bacteria Bacillus amyloliquefaciens NBRISN13 modulates gene expression profile of leaf and rhizosphere community in rice during salt stress.

    PubMed

    Nautiyal, Chandra Shekhar; Srivastava, Suchi; Chauhan, Puneet Singh; Seem, Karishma; Mishra, Aradhana; Sopory, Sudhir Kumar

    2013-05-01

    Growth and productivity of rice and soil inhabiting microbial population is negatively affected by soil salinity. However, some salt resistant, rhizosphere competent bacteria improve plant health in saline stress. Present study evaluated the effect of salt tolerant Bacillus amyloliquefaciens NBRISN13 (SN13) inoculation on rice plants in hydroponic and soil conditions exposed to salinity. SN13 increased plant growth and salt tolerance (NaCl 200 mM) and expression of at least 14 genes under hydroponic and soil conditions in rice. Among these 14 genes 4 (NADP-Me2, EREBP, SOSI, BADH and SERK1) were up-regulated and 2 (GIG and SAPK4) repressed under salt stress in hydroponic condition. In greenhouse experiment, salt stress resulted in accumulation of MAPK5 and down-regulation of the remaining 13 transcripts was observed. SN13 treatment, with or without salt gave similar expression for all tested genes as compared to control. Salt stress caused changes in the microbial diversity of the rice rhizosphere and stimulated population of betaine-, sucrose-, trehalose-, and glutamine-utilizing bacteria in salt-treated rice rhizosphere (SN13 + salt). The observations imply that SN13 confers salt tolerance in rice by modulating differential transcription in a set of at least 14 genes. Stimulation of osmoprotectant utilizing microbial population as a mechanism of inducing salt tolerance in rice is reported for the first time in this study to the best of our knowledge. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  5. Rice-planted area extraction from multi-temporal remote sensing images

    NASA Astrophysics Data System (ADS)

    Shen, Jinxiang; Zhang, Hong; Ma, Yanmei

    2015-12-01

    Rice-planted area and production monitoring has significance for governments to formulate some food related policy. Remote sensing has an obvious advantage for the rice monitoring. As for the rice-planted area, the special growth raw shows different feature in the remote sensing image. In this paper, the multi-temporal Landsat-8 OLI image of Menghun and Mengzhe town in Xishuangbanna autonomous prefecture where planting a large number of rice was used as the test data, the corresponding changes of the difference between NDVI and NDWI was used as the diagnostic feature, and the SAM classification approach was introduced to extract rice-planted area. The experiments shows that the approach could acquire more than 95% of the extraction accuracy.

  6. Effect of reduced plant height on drought tolerance in rice.

    PubMed

    Ahmadikhah, Asadollah; Marufinia, Amir

    2016-12-01

    Drought stress due to water deficit is a major problem of rice cultivation as a most drought-sensitive crop plant. A rice mutant line (MT58) was developed after mutagenesis of cv. Neda by ethyl methane sulfonate (EMS) and selected for dwarfism (18 cm shorter than Neda). The extent of its molecular changes relative to parental cultivar was assessed by SSR and ISSR markers, and the response of the line along with parental cultivar and another mutant line (MTA) to mild and severe water deficit, was evaluated in a field experiment. A molecular assessment using 41 SSR markers showed that dwarf line MT58 had significant molecular difference with two other lines. ISSR assay also proved the considerable mutational effect of EMS on two mutant lines compared with the original wild line. Field experiments revealed that limited irrigation caused mild-to-severe decrease in all the studied traits, including chlorophyll contents. In mild water-stress mutant line, MT58 showed a low (3 %) yield loss as compared with cultivar Neda with a high (14 %) yield loss. Interestingly, in severe water-stress mutant line, MT58 showed a low (19 %) yield loss as compared with mutant line MTA and cv. Neda with high (33 and 31 %, respectively) yield loss. In severe stress, mutant MT58 had the highest values of panicle length, total kernels per panicle, fertile kernels, and chlorophyll contents, while cv. Neda had the highest values of plant height, tiller number, and plant yield, and reduction in chlorophyll content at drought stress condition was correlated with yield loss (0.64 and 0.697 for chl.a and chl.b, respectively). The results of this research obviously confirm that mutant line MT58 despite of its stunt figure shows a low yield loss due to drought stress and hence is a promising line for cultivation under drought condition.

  7. Evaluation of bacteria isolated from rice for plant growth promotion and biological control of seedling disease of rice.

    PubMed

    Adhikari, T B; Joseph, C M; Yang, G; Phillips, D A; Nelson, L M

    2001-10-01

    Of 102 rhizoplane and endophytic bacteria isolated from rice roots and stems in California, 37% significantly (P < or = 0.05) inhibited the growth in vitro of two pathogens, Achlya klebsiana and Pythium spinosum, causing seedling disease of rice. Four endophytic strains were highly effective against seedling disease in growth pouch assays, and these were identified as Pseudomonas fluorescens (S3), Pseudomonas tolaasii (S20), Pseudomonas veronii (S21), and Sphingomonas trueperi (S12) by sequencing of amplified 16S rRNA genes. Strains S12, S20, and S21 contained the nitrogen fixation gene, nifD, but only S12 was able to reduce acetylene in pure culture. The four strains significantly enhanced plant growth in the absence of pathogens, as evidenced by increases in plant height and dry weight of inoculated rice seedlings relative to noninoculated rice. Three bacterial strains (S3, S20, and S21) were evaluated in pot bioassays and reduced disease incidence by 50%-73%. Strain S3 was as effective at suppressing disease at the lowest inoculum density (106 CFU/mL) as at higher density (10(8) CFU/mL or undiluted suspension). This study indicates that selected endophytic bacterial strains have potential for control of seedling disease of rice and for plant growth promotion.

  8. 2D-DIGE-based proteome expression changes in leaves of rice seedlings exposed to low-level gamma radiation at Iitate village, Fukushima

    PubMed Central

    Hayashi, Gohei; Moro, Carlo F; Rohila, Jai Singh; Shibato, Junko; Kubo, Akihiro; Imanaka, Tetsuji; Kimura, Shinzo; Ozawa, Shoji; Fukutani, Satoshi; Endo, Satoru; Ichikawa, Katsuki; Agrawal, Ganesh Kumar; Shioda, Seiji; Hori, Motohide; Fukumoto, Manabu; Rakwal, Randeep

    2015-01-01

    The present study continues our previous research on investigating the biological effects of low-level gamma radiation in rice at the heavily contaminated Iitate village in Fukushima, by extending the experiments to unraveling the leaf proteome. 14-days-old plants of Japonica rice (Oryza sativa L. cv. Nipponbare) were subjected to gamma radiation level of upto 4 µSv/h, for 72 h. Following exposure, leaf samples were taken from the around 190 µSv/3 d exposed seedling and total proteins were extracted. The gamma irradiated leaf and control leaf (harvested at the start of the experiment) protein lysates were used in a 2-D differential gel electrophoresis (2D-DIGE) experiment using CyDye labeling in order to asses which spots were differentially represented, a novelty of the study. 2D-DIGE analysis revealed 91 spots with significantly different expression between samples (60 positive, 31 negative). MALDI-TOF and TOF/TOF mass spectrometry analyses revealed those as comprising of 59 different proteins (50 up-accumulated, 9 down-accumulated). The identified proteins were subdivided into 10 categories, according to their biological function, which indicated that the majority of the differentially expressed proteins consisted of the general (non-energy) metabolism and stress response categories. Proteome-wide data point to some effects of low-level gamma radiation exposure on the metabolism of rice leaves. PMID:26451896

  9. 2D-DIGE-based proteome expression changes in leaves of rice seedlings exposed to low-level gamma radiation at Iitate village, Fukushima.

    PubMed

    Hayashi, Gohei; Moro, Carlo F; Rohila, Jai Singh; Shibato, Junko; Kubo, Akihiro; Imanaka, Tetsuji; Kimura, Shinzo; Ozawa, Shoji; Fukutani, Satoshi; Endo, Satoru; Ichikawa, Katsuki; Agrawal, Ganesh Kumar; Shioda, Seiji; Hori, Motohide; Fukumoto, Manabu; Rakwal, Randeep

    2015-01-01

    The present study continues our previous research on investigating the biological effects of low-level gamma radiation in rice at the heavily contaminated Iitate village in Fukushima, by extending the experiments to unraveling the leaf proteome. 14-days-old plants of Japonica rice (Oryza sativa L. cv. Nipponbare) were subjected to gamma radiation level of upto 4 µSv/h, for 72 h. Following exposure, leaf samples were taken from the around 190 µSv/3 d exposed seedling and total proteins were extracted. The gamma irradiated leaf and control leaf (harvested at the start of the experiment) protein lysates were used in a 2-D differential gel electrophoresis (2D-DIGE) experiment using CyDye labeling in order to asses which spots were differentially represented, a novelty of the study. 2D-DIGE analysis revealed 91 spots with significantly different expression between samples (60 positive, 31 negative). MALDI-TOF and TOF/TOF mass spectrometry analyses revealed those as comprising of 59 different proteins (50 up-accumulated, 9 down-accumulated). The identified proteins were subdivided into 10 categories, according to their biological function, which indicated that the majority of the differentially expressed proteins consisted of the general (non-energy) metabolism and stress response categories. Proteome-wide data point to some effects of low-level gamma radiation exposure on the metabolism of rice leaves.

  10. 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.

  11. Evaluating leaf and canopy reflectance of stressed rice plants to monitor arsenic contamination

    USDA-ARS?s Scientific Manuscript database

    Arsenic contamination is a serious problem in rice cultivated soils of many developing countries. Hence, it is critical to monitor and control arsenic uptake in rice plants to avoid adverse effects on human health. This study evaluated the feasibility of using reflectance spectroscopy to monitor ars...

  12. Growth and Survival of Baldcypress Planted in an Old Rice Field of Coastal South Carolina

    Treesearch

    William H. Conner; L. Wayne Inabinette; Mehmet Ozalp

    2004-01-01

    Vast acreages of baldcypress [Taxodium distichum (L.) Rich.] swampland in coastal South Carolina were cleared for rice production starting in the late 1600s. When rice cultivation ended in the late 1800s, many cultivated areas became marshlands. Other fields failed to return to forest unless they were planted. In one such area, nine acres were...

  13. Synthesis of hemoglobins in rice (Oryza sativa var. Jackson) plants growing in normal and stress conditions.

    PubMed

    Lira-Ruan, V; Sarath, G; Klucas, R V.; Arredondo-Peter, R

    2001-07-01

    In rice (Oryza sativa var. Jackson) at least three copies of hemoglobin (hb) gene exist. Rice hb1 and hb2 genes are differentially expressed in roots and leaves from mature plants. We used polyclonal antibodies raised to recombinant rice Hb1 and Western blotting to analyze the synthesis of Hbs in rice plants growing under normal or stress conditions. Results showed that rice Hbs are synthesized in coleoptiles, seminal roots and embryos from seeds germinated for 6 days, and also in leaves and roots from plants 2-14 weeks after germination. Analysis of Hb synthesis in stressed rice showed that: (i) level of Hbs was higher in etiolated than control plants, (ii) level of Hbs increased in roots from flooded rice, and (iii) level of Hbs did not change under oxidative (H(2)O(2)), nitrosative (SNP) and hormonal (2,4-D) stresses. These results suggest that the effect of light withdrawal in etiolated leaves and O(2)-limiting conditions in flooded roots, but not oxidative, nitrosative and hormonal stresses, modulate the synthesis of rice Hbs.

  14. Transgenic rice plants expressing human p450 genes involved in xenobiotic metabolism for phytoremediation.

    PubMed

    Kawahigashi, Hiroyuki; Hirose, Sakiko; Ohkawa, Hideo; Ohkawa, Yasunobu

    2008-01-01

    Phytoremediation is the use of plants to remove xenobiotic compounds from the environment. Plants have the inherent ability to detoxify xenobiotic pollutants, but they are generally poor at degrading them. The introduction of genes involved in xenobiotic degradation is aimed at enhancing plants' potential further. Rice (Oryza sativa) is a good candidate for this purpose and has been transformed with genes encoding cytochrome P450 monooxygenases CYP1A1, CYP2B6, and CYP2C19. The transgenic plants were more tolerant to various herbicides than nontransgenic Nipponbare rice plants, owing to enhanced metabolism by the introduced P450 enzymes. Transgenic plants were able to remove atrazine and metolachlor from soil. Field testing and risk assessment are very important for developing transgenic plants for phytoremediation. Transgenic rice plants should become useful as herbicide-tolerant crops and for phytoremediation of xenobiotic pollutants in future.

  15. 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.

  16. Effects on growth, development, chlorophyll content and their reversibility in rice and wheat seeds when exposed to altered (micro and hyper) gravity conditions

    NASA Astrophysics Data System (ADS)

    Jagtap, Sagar

    2012-07-01

    Effects of altered gravity (micro and hyper) on growth and chlorophyll content in various plants have been studied by many researchers but very conflicting results were obtained. Also most of the previous reports lack reversibility experiments in their studies. The present work consists of the use of 1-dimensional clinostat which conventionally offers a simulated microgravity condition and centrifuge which offers hypergravity condition. New experimental methodologies are developed to study the effects of simulated microgravity (clinorotation) and hypergravity conditions on plant growth, development, chlorophyll content and their reversibility in rice and wheat seeds. Results obtained show that effects of simulated microgravity (slow clinorotation) on growth and chlorophyll content may depend on the period of exposure to clinorotation. Also simulated microgravity exposure could enhance growth, yield and quality in rice sowed in field under normal gravity (1 g) conditions. This is a novel observation and may be beneficial in future for improving crop productivity of various cereals including rice. However, a short interval, post imbibition hypergravity exposure of seeds showed retardation in growth and decrease in chlorophyll content when sowed under normal gravity (1 g) conditions. Results of Environmental Scanning Electron Microscopy (ESEM) show that there is no any physiological damage to hypergravity exposed seeds indicating hypergravity-induced changes in growth and the chlorophyll content can be recognized as normal physiological responses of plants i.e. a molecular mechanism must be involved in it. Results of reversibility experiments and analysis of mineral nutrients such as protein content, amylase activity and Energy-dispersive X-ray (EDAX) also support this hypothesis.

  17. 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.

  18. Accumulation of total mercury and methylmercury in rice plants collected from different mining areas in China.

    PubMed

    Meng, Mei; Li, Bing; Shao, Jun-juan; Wang, Thanh; He, Bin; Shi, Jian-bo; Ye, Zhi-hong; Jiang, Gui-bin

    2014-01-01

    A total of 155 rice plants were collected from ten mining areas in three provinces of China (Hunan, Guizhou and Guangdong), where most of mercury (Hg) mining takes place in China. During the harvest season, whole rice plants were sampled and divided into root, stalk & leaf, husk and seed (brown rice), together with soil from root zone. Although the degree of Hg contamination varied significantly among different mining areas, rice seed showed the highest ability for methylmercury (MeHg) accumulation. Both concentrations of total mercury (THg) and MeHg in rice plants were significantly correlated with Hg levels in soil, indicating soil is still an important source for both inorganic mercury (IHg) and MeHg in rice plants. The obvious discrepancy between the distribution patterns of THg and MeHg reflected different pathways of IHg and MeHg accumulation. Water soluble Hg may play more important role in MeHg accumulation in rice plants. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Mechanism of methane transport from the rhizosphere to the atmosphere through rice plants

    SciTech Connect

    Nouchi, Isamu ); Mariko, Shigeru ); Aoki, Kazuyuki )

    1990-09-01

    To clarify the mechanisms of methane transport from the rhizosphere into the atmosphere through rice plants (Oryza sativa L.), the methane emission rate was measured from a shoot whose roots had been kept in a culture solution with a high methane concentration or exposed to methane gas in the gas phase by using a cylindrical chamber. No clear correlation was observed between change in the transpiration rate and that in the methane emission rate. Methane was mostly released from the culm, which is an aggregation of leaf sheaths, but not from the leaf blade. Micropores which are different from stomata were newly found at the abaxial epidermis of the leaf sheath by scanning electron microscopy. The measured methane emission rate was much higher than the calculated methane emission rate that would result from transpiration and the methane concentration in the culture solution. Rice roots absorb methane gas in the gas phase without water uptake. These results suggest that methane dissolved in the soil water surrounding the roots diffuses into the cell-wall water of the root cells, gasifies in the root cortex, and then is mostly released through the micropores in the leaf sheaths.

  20. 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), Na2SO4) 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.

  1. Cytosolic APX knockdown rice plants sustain photosynthesis by regulation of protein expression related to photochemistry, Calvin cycle and photorespiration.

    PubMed

    Carvalho, Fabrício E L; Ribeiro, Carolina W; Martins, Márcio O; Bonifacio, Aurenivia; Staats, Charley C; Andrade, Cláudia M B; Cerqueira, João V; Margis-Pinheiro, Márcia; Silveira, Joaquim A G

    2014-04-01

    The biochemical mechanisms underlying the involvement of cytosolic ascorbate peroxidases (cAPXs) in photosynthesis are still unknown. In this study, rice plants doubly silenced in these genes (APX1/2) were exposed to moderate light (ML) and high light (HL) to assess the role of cAPXs in photosynthetic efficiency. APX1/2 mutants that were exposed to ML overexpressed seven and five proteins involved in photochemical activity and photorespiration, respectively. These plants also increased the pheophytin and chlorophyll levels, but the amount of five proteins that are important for Calvin cycle did not change. These responses in mutants were associated with Rubisco carboxylation rate, photosystem II (PSII) activity and potential photosynthesis, which were similar to non-transformed plants. The upregulation of photochemical proteins may be part of a compensatory mechanism for APX1/2 deficiency but apparently the finer-control for photosynthesis efficiency is dependent on Calvin cycle proteins. Conversely, under HL the mutants employed a different strategy, triggering downregulation of proteins related to photochemical activity, Calvin cycle and decreasing the levels of photosynthetic pigments. These changes were associated to strong impairment in PSII activity and Rubisco carboxylation. The upregulation of some photorespiratory proteins was maintained under that stressful condition and this response may have contributed to photoprotection in rice plants deficient in cAPXs. The data reveal that the two cAPXs are not essential for photosynthesis in rice or, alternatively, the deficient plants are able to trigger compensatory mechanisms to photosynthetic acclimation under ML and HL conditions. These mechanisms involve differential regulation in protein expression related to photochemistry, Calvin cycle and photorespiration.

  2. Arsenic in rice agrosystems (water, soil and rice plants) in Guayas and Los Ríos provinces, Ecuador.

    PubMed

    Otero, X L; Tierra, W; Atiaga, O; Guanoluisa, D; Nunes, L M; Ferreira, T O; Ruales, J

    2016-12-15

    Geogenic arsenic (As) can accumulate and reach high concentrations in rice grains, thus representing a potential threat to human health. Ecuador is one of the main consumers of rice in South America. However, there is no information available about the concentrations of As in rice agrosystems, although some water bodies are known to contain high levels of the element. We carried out extensive sampling of water, soil, rice plants and commercial rice (obtained from local markets). Water samples were analysed to determine physico-chemical properties and concentrations of dissolved arsenic. Soil samples were analysed to determine total organic C, texture, total Fe and amorphous Fe oxyhydroxides (FeOx), total arsenic (tAs) and the bioavailable fraction (AsMe). The different plant parts were analysed separately to determine total (tAs), inorganic (iAs) and organic arsenic (oAs). Low concentrations of arsenic were found in samples of water (generally <10μgl(-1)) and soil (4.48±3mgkg(-1)). The tAs in the rice grains was within the usual range (0.042-0.125mgkg(-1) dry weight, d.w.) and was significantly lower than in leaves (0.123-0.286mgkg(-1) d.w.) and stems (0.091-0.201mgkg(-1) d.w.). The FeOx and tAs and also AsMe in flood water were negatively correlated with tAs in the plants. However, the concentrations of As in stems and leaves were linearly correlated with tAs in the soil and flood water. The relationship between tAs and arsenic in the grain fitted a logarithmic function, as did that between tAs in the grain and the stem. The findings seem to indicate that high concentrations of arsenic in the environment (soil or water) or in the rice stem do not necessarily imply accumulation of the element in the grain. The iAs form was dominant (>80%) in all parts of the rice plants. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Rice (Oryza sativa) Laccases Involved in Modification and Detoxification of Herbicides Atrazine and Isoproturon Residues in Plants.

    PubMed

    Huang, Meng Tian; Lu, Yi Chen; Zhang, Shuang; Luo, Fang; Yang, Hong

    2016-08-24

    Atrazine (ATR) and isoproturon (IPU) as herbicides have become serious environmental contaminants due to their overuse in crop production. Although ATR and IPU in soils are easily absorbed by many crops, the mechanisms for their degradation or detoxification in plants are poorly understood. This study identified a group of novel genes encoding laccases (EC 1.10.3.2) that are possibly involved in catabolism or detoxification of ATR and IPU residues in rice. Transcriptome profiling shows at least 22 differentially expressed laccase genes in ATR/IPU-exposed rice. Some of the laccase genes were validated by RT-PCR analysis. The biochemical properties of the laccases were analyzed, and their activities in rice were induced under ATR/IPU exposure. To investigate the roles of laccases in degrading or detoxifying ATR/IPU in rice, transgenic yeast cells (Pichia pastoris X-33) expressing two rice laccase genes (LOC_Os01g63180 and LOC_Os12g15680) were generated. Both transformants were found to accumulate less ATR/IPU compared to the control. The ATR/IPU-degraded products in the transformed yeast cells using UPLC-TOF-MS/MS were further characterized. Two metabolites, hydroxy-dehydrogenated atrazine (HDHA) and 2-OH-isopropyl-IPU, catalyzed by laccases were detected in the eukaryotic cells. These results indicate that the laccase-coding genes identified here could confer degradation or detoxification of the herbicides and suggest that the laccases could be one of the important enzymatic pathways responsible for ATR/IPU degradation/detoxification in rice.

  4. Transgenic rice plants expressing cry1Ia5 gene are resistant to stem borer (Chilo agamemnon).

    PubMed

    Moghaieb, Reda E A

    2010-01-01

    The stem borer, Chilo agamemnon Bles., is the most serious insect pest in rice fields of the Egyptian Nile Delta. To induce rice plant resistance to Chilo agamemnon, the cry1Ia5 gene was introduced to rice plants (Oryza sativa L.). The integration of the cry1Ia5 gene into the plant genome was confirmed using PCR and Southern blot analyses. The obtained plantlets were transferred to the greenhouse until seeds were collected. Northern blot analysis of the T1 plants confirmed the expression of the cry1Ia5 gene. The insecticidal activity of the transgenic plants against the rice stem borer Chilo agamemnon were tested. The third larval instars were fed on stem cuts from three transgenic lines (L1, L2 and L3) as well as cuts from the control (gfp-transgenic) plants for one week and the mortality percentage was daily recorded. Transgenic line-3 showed the highest mortality percentage after one day (50%) followed by L2 (25%) then L1 (0%). Two days post treatment the mortality percentage increased to 70, 45 and 25% for transgenic lines 1, 2 and 3 respectively. Mortality of 100% was recorded four days post treatment, while those fed on the gfp-transgenic rice (control) showed 0% mortality. Thus, transgenic plants showed high resistance to stem borers and can serve as a novel genetic resource in breeding programs. Transgenic plants expressing BT protein were normal in phenotype with as good seed setting as the nontransgenic control plants.

  5. [Effects of applying nitrogen fertilizer and fertilizer additive on rice yield and rice plant nitrogen uptake, translocation, and utilization].

    PubMed

    Li, Wen-jun; Xia, Yong-qiu; Yang, Xiao-yun; Guo, Miao; Yan, Xiao-yuan

    2011-09-01

    A field experiment was conducted in the Taihu Lake region of southern Jiangsu to study the effects of applying nitrogen (N) fertilizer and fertilizer additive on the rice yield and the rice plant N uptake, translocation, and utilization. Applying N fertilizer had significant positive effects on the rice yield, accumulative absorbed N at all growth stages and at each growth stage, and N translocation rate after anthesis (P < 0.01). However, when the N application rate exceeded 200 kg x hm(-2), its yield-increasing effect was not significant (P > 0.05). The N translocation rate after anthesis and the N fertilizer use efficiency decreased with increasing N application rate. Applying fertilizer additive further improved the rice yield, accumulative absorbed N, N translocation rate after anthesis, and N fertilizer use efficiency, and this effect was more evident when the N application rate was equal to or greater than 200 kg x hm(-2). Relatively high rice yield and N use efficiency were achieved when applying 150 kg x hm(-2) of N fertilizer without the application of fertilizer additive.

  6. Rice planting systems, global warming and outbreaks of Nilaparvata lugens (Stål).

    PubMed

    Hu, G; Cheng, X N; Qi, G J; Wang, F Y; Lu, F; Zhang, X X; Zhai, B P

    2011-04-01

    Brown Planthopper (BPH, Nilaparvata lugens (Stål)) is one of the most serious pests of rice in both temperate and tropical regions of East and South Asia and has become especially problematic over the past few years. In order to analyze the effect of the change of rice cropping system on the population dynamics of BPH, field surveys of the occurrence and distribution of BPH were performed and other relevant data, including light trap data and ovary dissection data were collected in nearly 40 Chinese counties encompassing six provinces (or municipalities), including Hainan, Guangxi, Anhui, Shanghai, Fujian and Guangdong from April to October in 2007.The mixed planting areas of single- and double-cropping rice in China include Hubei, South and Central Anhui, North Hunan, and North Jiangxi. In these areas, double-cropping rice has now been greatly reduced and single-cropping rice has been rapidly increasing since 1997. The surveys revealed that when the immigration peak of BPH occurred in June and July, the single-cropping rice was at the tillering to booting stage and fit for BPH, but early rice had already matured and most of late rice had not yet been transplanted. BPH immigrants from southern rice areas prefer to inhabit and breed in single-cropping rice paddies. Moreover, farming activities between early rice and late rice interrupted the continuous growth of BPH populations in double-cropping rice paddies. As a result, in comparison with data collected 30 years ago, the spatiotemporal dynamics and migration patterns of BPH have dramatically changed in the lower-middle reaches of the Yangtze River. In the mixed planting areas, due to their high suitability, the BPH population in single-cropping rice grew so quickly that it caused serious local damage and there was mass emigration of macropterous progeny to the Yangtze River Delta in late August and early September.Global warming may also affect BPH populations, where results suggest steadily warmer autumns have

  7. 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.

  8. [Hyperspectral remote sensing diagnosis models of rice plant nitrogen nutritional status].

    PubMed

    Tan, Chang-Wei; Zhou, Qing-Bo; Qi, La; Zhuang, Heng-Yang

    2008-06-01

    The correlations of rice plant nitrogen content with raw hyperspectral reflectance, first derivative hyperspectral reflectance, and hyperspectral characteristic parameters were analyzed, and the hyperspectral remote sensing diagnosis models of rice plant nitrogen nutritional status with these remote sensing parameters as independent variables were constructed and validated. The results indicated that the nitrogen content in rice plant organs had a variation trend of stem < sheath < spike < leaf. The spectral reflectance at visible light bands was leaf < spike < sheath < stem, but that at near-infrared bands was in adverse. The linear and exponential models with the raw hyperspectral reflectance at 796.7 nm and the first derivative hyperspectral reflectance at 738.4 nm as independent variables could better diagnose rice plant nitrogen nutritional status, with the decisive coefficients (R2) being 0.7996 and 0.8606, respectively; while the model with vegetation index (SDr - SDb) / (SDr + SDb) as independent variable, i. e., y = 365.871 + 639.323 ((SDr - SDb) / (SDr + SDb)), was most fit rice plant nitrogen content, with R2 = 0.8755, RMSE = 0.2372 and relative error = 11.36%, being able to quantitatively diagnose the nitrogen nutritional status of rice.

  9. Unexpected Increases in Fecundity of Ceriodaphnia dubia Exposed to Reused Rice Irrigation Water.

    PubMed

    Grippo, Richard S; McNeely, Van M; Farris, Jerry L

    2016-06-01

    Steady increases in agricultural irrigation raise concerns about environmental impacts. Rice producing regions face declining irrigation groundwater and have started reusing irrigation water as a substitute. The goal of this project was to determine if reused irrigation water is potentially toxic compared to conventional well irrigation water. Reused and well water samples, collected from three Arkansas rice farms at field inlets and outlets on three dates corresponding to fertilizer/chemical applications or crop management, were used in acute 48-h (Pimephales promelas) and chronic (Ceriodaphnia dubia) toxicity evaluations. Acute toxicity tests indicated no effects on P. promelas. Fecundity of C. dubia was significantly increased in the reused water inlet and in both the reused and well water rice field outlets compared to well water inlets and laboratory reference water. This study suggests that, compared to well water, reused rice irrigation water has reduced potential for significant negative environmental impact on biota in receiving waters.

  10. 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.

  11. Membrane stability of winter wheat plants exposed to subzero temperatures for variable lengths of time

    USDA-ARS?s Scientific Manuscript database

    The ability to survive episodes of subfreezing temperature is essential to winter wheat. Fully cold-acclimated plants of six lines of winter wheat were exposed to -12, -14, -16 or -18° C, four 1-5 hours. Electrolyte leakage and plant survival were used to assess damage to the plants. Plants exposed ...

  12. Ascending migration of endophytic rhizobia, from roots to leaves, inside rice plants and assessment of benefits to rice growth physiology.

    PubMed

    Chi, Feng; Shen, Shi-Hua; Cheng, Hai-Ping; Jing, Yu-Xiang; Yanni, Youssef G; Dazzo, Frank B

    2005-11-01

    Rhizobia, the root-nodule endosymbionts of leguminous plants, also form natural endophytic associations with roots of important cereal plants. Despite its widespread occurrence, much remains unknown about colonization of cereals by rhizobia. We examined the infection, dissemination, and colonization of healthy rice plant tissues by four species of gfp-tagged rhizobia and their influence on the growth physiology of rice. The results indicated a dynamic infection process beginning with surface colonization of the rhizoplane (especially at lateral root emergence), followed by endophytic colonization within roots, and then ascending endophytic migration into the stem base, leaf sheath, and leaves where they developed high populations. In situ CMEIAS image analysis indicated local endophytic population densities reaching as high as 9 x 10(10) rhizobia per cm3 of infected host tissues, whereas plating experiments indicated rapid, transient or persistent growth depending on the rhizobial strain and rice tissue examined. Rice plants inoculated with certain test strains of gfp-tagged rhizobia produced significantly higher root and shoot biomass; increased their photosynthetic rate, stomatal conductance, transpiration velocity, water utilization efficiency, and flag leaf area (considered to possess the highest photosynthetic activity); and accumulated higher levels of indoleacetic acid and gibberellin growth-regulating phytohormones. Considered collectively, the results indicate that this endophytic plant-bacterium association is far more inclusive, invasive, and dynamic than previously thought, including dissemination in both below-ground and above-ground tissues and enhancement of growth physiology by several rhizobial species, therefore heightening its interest and potential value as a biofertilizer strategy for sustainable agriculture to produce the world's most important cereal crops.

  13. Regulation of proline accumulation in detached rice leaves exposed to excess copper.

    PubMed

    Chen, C T.; Chen, L -M.; Lin, C C.; Kao, C H.

    2001-01-05

    Accumulation of proline in response to excess Cu was studied in detached leaves of rice (Oryza sativa). CuSO(4) was effective in inducing proline accumulation in detached rice leaves under both light and dark conditions. CuSO(4) and CuCl(2) were equally effective in inducing proline accumulation, indicating that proline accumulation is induced by Cu. Sulfate salts of Mg, Mn, and Fe were ineffective in inducing proline accumulation in detached rice leaves. Excess Cu had no effect on relative water content of detached rice leaves, suggesting that Cu-induced proline accumulation is unlikely due to water deficit. Proline accumulation induced by excess Cu was related to proteolysis and an increase in Delta(1)-pyrroline-5-carboxylate reductase or ornithine-delta-aminotransferase activity and could not be explained by proline utilization or stress-induced modifications in proline dehydrogenase or Delta(1)-pyrroline-5-carboxylate dehydrogenase. The content of glutamic acid decreased by excess Cu. The increase in arginine but not ornithine was found to be associated with the increase in proline content in Cu-stressed detached rice leaves. CuSO(4) treatment resulted in an increase in abscisic acid content in detached rice leaves. The possibility that proline accumulation induced by excess Cu is mediated through abscisic acid is discussed.

  14. Pathways and relative contributions to arsenic volatilization from rice plants and paddy soil.

    PubMed

    Jia, Yan; Huang, Hai; Sun, Guo-Xin; Zhao, Fang-Jie; Zhu, Yong-Guan

    2012-08-07

    Recent studies have shown that higher plants are unable to methylate arsenic (As), but it is not known whether methylated As species taken up by plants can be volatilized. Rice (Oryza sativa L.) plants were grown axenically or in a nonsterile soil using a two-chamber system. Arsenic transformation and volatilization were investigated. In the axenic system, uptake of As species into rice roots was in the order of arsenate (As(V)) > monomethylarsonic acid (MMAs(V)) > dimethylarsinic acid (DMAs(V)) > trimethylarsine oxide (TMAs(V)O), but the order of the root-to-shoot transport index (Ti) was reverse. Also, volatilization of trimethylarsine (TMAs) from rice plants was detected when plants were treated with TMAs(V)O but not with As(V), DMAs(V), or MMAs(V). In the soil culture, As was volatilized mainly from the soil. Small amounts of TMAs were also volatilized from the rice plants, which took up DMAs(V), MMAs(V), and TMAs(V)O from the soil solution. The addition of dried distillers grain (DDG) to the soil enhanced As mobilization into the soil solution, As methylation and volatilization from the soil, as well as uptake of different As species and As volatilization from the rice plants. Results show that rice is able to volatilize TMAs after the uptake of TMAs(V)O but not able to convert inorganic As, MMAs(V) or DMAs(V) into TMAs and that the extent of As volatilization from rice plants was much smaller than that from the flooded soil.

  15. 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.

  16. Herbicide resistance of transgenic rice plants expressing human CYP1A1.

    PubMed

    Kawahigashi, Hiroyuki; Hirose, Sakiko; Ohkawa, Hideo; Ohkawa, Yasunobu

    2007-01-01

    Cytochrome P450 monooxygenases (P450s) metabolize herbicides to produce mainly non-phytotoxic metabolites. Although rice plants endogenously express multiple P450 enzymes, transgenic plants expressing other P450 isoforms might show improved herbicide resistance or reduce herbicide residues. Mammalian P450s metabolizing xenobiotics are reported to show a broad and overlapping substrate specificity towards lipophilic foreign chemicals, including herbicides. These P450s are ideal for enhancing xenobiotic metabolism in plants. A human P450, CYP1A1, metabolizes various herbicides with different structures and modes of herbicide action. We introduced human CYP1A1 into rice plants, and the transgenic rice plants showed broad cross-resistance towards various herbicides and metabolized them. The introduced CYP1A1 enhanced the metabolism of chlorotoluron and norflurazon. The herbicides were metabolized more rapidly in the transgenic rice plants than in non-transgenic controls. Transgenic rice plants expressing P450 might be useful for reducing concentrations of various chemicals in the environment.

  17. [Analysis of the transgenic rice plants derived from transformed anther calli].

    PubMed

    Jiang, Su; Chen, Cai-Yan; Cheng, Zhu-Kuan; Cai, Run; Zhai, Wen-Xue; Zhu, Li-Huang

    2004-12-01

    Rice calli derived from anther culture were used as recipient to transfer a rice blight resistance gene, Xa21, into a japonica rice variety, Taipei 309, via Agrobacterium-mediated transformation. Seven green transgenic plants, including one mixoploid, two haploid, and four diploid plants, were regenerated. PCR, Southern blot, FISH and blight resistance analysis all indicated that Xa21 gene has been integrated into the T0 plant genomes. T1 generations of the four diploid T0 plants were further investigated for resistance segregation. Chi2 test showed that two T1 populations segregated with a ratio of 3:1, indicating that a single copy of Xa21 gene was integrated into the genome, whereas the segregation ratios of the other two T1 populations were non-Mendelian. Therefore, the four diploid transgenic plants should be heterozygous diploids.

  18. Pathogen effectors and plant immunity determine specialization of the blast fungus to rice subspecies

    PubMed Central

    Liao, Jingjing; Huang, Huichuan; Meusnier, Isabelle; Adreit, Henri; Ducasse, Aurélie; Bonnot, François; Pan, Lei; He, Xiahong; Kroj, Thomas; Fournier, Elisabeth; Tharreau, Didier; Gladieux, Pierre; Morel, Jean-Benoit

    2016-01-01

    Understanding how fungi specialize on their plant host is crucial for developing sustainable disease control. A traditional, centuries-old rice agro-system of the Yuanyang terraces was used as a model to show that virulence effectors of the rice blast fungus Magnaporthe oryzaeh play a key role in its specialization on locally grown indica or japonica local rice subspecies. Our results have indicated that major differences in several components of basal immunity and effector-triggered immunity of the japonica and indica rice varieties are associated with specialization of M. oryzae. These differences thus play a key role in determining M. oryzae host specificity and may limit the spread of the pathogen within the Yuanyang agro-system. Specifically, the AVR-Pia effector has been identified as a possible determinant of the specialization of M. oryzae to local japonica rice. DOI: http://dx.doi.org/10.7554/eLife.19377.001 PMID:28008850

  19. Aquatic plants exposed to pharmaceuticals: effects and risks.

    PubMed

    Brain, Richard A; Hanson, Mark L; Solomon, Keith R; Brooks, Bryan W

    2008-01-01

    largely overlooked in the risk assessment process to date, which typically relies heavily on physiological and/or morphological endpoints for deriving toxicity data. However, a small number of studies have indicated that measuring the response of a pathway- or receptor-specific target in conjunction with a physiological endpoint with direct relatedness can yield sublethal responses that are two to three times more sensitive that the traditional gross morphological endpoints typically employed in risk assessment. The risk assessment for this review was based almost entirely on evaluations of gross morphological endpoints, which generally indicated that the risk pharmaceuticals pose to aquatic plants is generally low, with a few exceptions, particularly blue-green algae exposed to antibiotics, and both green and blue-green algae exposed to triclosan. It is critical to note, however, that the application of sublethal pathway or receptor-specific responses in risk assessment has largely been unconsidered, and future research is needed to elucidate whether evaluating the toxicity of pharmaceuticals using these endpoints provides a more sensitive, subtle, yet meaningful indication of toxicity than the traditional endpoints used in prospective and retrospective risk assessments for aquatic plants.

  20. Untapped Endophytic Colonization and Plant Growth-Promoting Potential of the Genus Novosphingobium to Optimize Rice Cultivation

    PubMed Central

    Rangjaroen, Chakrapong; Sungthong, Rungroch; Rerkasem, Benjavan; Teaumroong, Neung; Noisangiam, Rujirek; Lumyong, Saisamorn

    2017-01-01

    With the aim of searching for potent diazotrophic bacteria that are free of public health concerns and optimize rice cultivation, the endophytic colonization and plant growth-promoting activities of some endophytic diazotrophic bacteria isolated from rice were evaluated. Among these bacteria, the emerging diazotrophic strains of the genus Novosphingobium effectively associated with rice plant interiors and consequently promoted the growth of rice, even with the lack of a nitrogen source. These results suggest that diazotrophic Novosphingobium is an alternative microbial resource for further development as a safe biological enhancer in the optimization of organic rice cultivation. PMID:28228608

  1. Information system of rice planting calendar based on ten-day (Dasarian) rainfall prediction

    SciTech Connect

    Susandi, Armi; Tamamadin, Mamad; Djamal, Erizal; Las, Irsal

    2015-09-30

    This paper describes information system of rice planting calendar to help farmers in determining the time for rice planting. The information includes rainfall prediction in ten days (dasarian) scale overlaid to map of rice field to produce map of rice planting in village level. The rainfall prediction was produced by stochastic modeling using Fast Fourier Transform (FFT) and Non-Linier Least Squares methods to fit the curve of function to the rainfall data. In this research, the Fourier series has been modified become non-linear function to follow the recent characteristics of rainfall that is non stationary. The results have been also validated in 4 steps, including R-Square, RMSE, R-Skill, and comparison with field data. The development of information system (cyber extension) provides information such as rainfall prediction, prediction of the planting time, and interactive space for farmers to respond to the information submitted. Interfaces for interactive response will be critical to the improvement of prediction accuracy of information, both rainfall and planting time. The method used to get this information system includes mapping on rice planting prediction, converting the format file, developing database system, developing website, and posting website. Because of this map was overlaid with the Google map, the map files must be converted to the .kml file format.

  2. Reproduction allocation and potential mechanism of individual allelopathic rice plants in the presence of competing barnyardgrass.

    PubMed

    Kong, Chui-Hua; Wang, Ming-Li; Wang, Peng; Ni, Han-Wen; Meng, Xiang-Rui

    2013-01-01

    In spite of increasing knowledge of allelopathic rice as an efficient component involved in paddy weed management, relatively little is known about its reproduction in response to competing weeds. Reproduction allocation of individual allelopathic rice plants in relation to monoculture and mixed culture with competing barnyardgrass in a paddy field was studied, along with analyses of soil nutrients and microbial communities to understand the potential mechanism. At a 1:1 barnyardgrass and rice mixture proportion identified from a replacement series study, biomass, grain yield and major parameters of individual allelopathic rice plants at the mature stage were increased by competing barnyardgrass. There was no difference in allelopathic rice root-zone soil ammonium N and Olsen P between monoculture and mixed culture. However, mixed culture altered soil microbial biomass C and communities. When mixed with barnyardgrass, allelopathic rice root zone had an 87% increase in soil microbial biomass C. Phospholipid fatty acid (PLFA) profiling indicated that the signature lipid biomarkers of bacteria, actinobacteria and fungi were affected by mixed culture. Principal component analysis clearly identified differences in the composition of PLFA in different soil samples. Allelopathic rice specific changes in soil microbial communities may generate a positive feedback on its own growth and reproduction in the presence of competing barnyardgrass in a given paddy system. Copyright © 2012 Society of Chemical Industry.

  3. PDH45 overexpressing transgenic tobacco and rice plants provide salinity stress tolerance via less sodium accumulation.

    PubMed

    Nath, Manoj; Garg, Bharti; Sahoo, Ranjan Kumar; Tuteja, Narendra

    2015-01-01

    Salinity stress negatively affects the crop productivity worldwide, including that of rice. Coping with these losses is a major concern for all countries. The pea DNA helicase, PDH45 is a unique member of helicase family involved in the salinity stress tolerance. However, the exact mechanism of the PDH45 in salinity stress tolerance is yet to be established. Therefore, the present study was conducted to investigate the mechanism of PDH45-mediated salinity stress tolerance in transgenic tobacco and rice lines along with wild type (WT) plants using CoroNa Green dye based sodium localization in root and shoot sections. The results showed that under salinity stress root and shoot of PDH45 overexpressing transgenic tobacco and rice accumulated less sodium (Na(+)) as compared to their respective WT. The present study also reports salinity tolerant (FL478) and salinity susceptible (Pusa-44) varieties of rice accumulated lowest and highest Na(+) level, respectively. All the varieties and transgenic lines of rice accumulate differential Na(+) ions in root and shoot. However, roots accumulate high Na(+) as compared to the shoots in both tobacco and rice transgenic lines suggesting that the Na(+) transport in shoot is somehow inhibited. It is proposed that the PDH45 is probably involved in the deposition of apoplastic hydrophobic barriers and consequently inhibit Na(+) transport to shoot and therefore confers salinity stress tolerance to PDH45 overexpressing transgenic lines. This study concludes that tobacco (dicot) and rice (monocot) transgenic plants probably share common salinity tolerance mechanism mediated by PDH45 gene.

  4. Plant defence suppression is mediated by a fungal sirtuin during rice infection by Magnaporthe oryzae.

    PubMed

    Fernandez, Jessie; Marroquin-Guzman, Margarita; Nandakumar, Renu; Shijo, Sara; Cornwell, Kathryn M; Li, Gang; Wilson, Richard A

    2014-10-01

    Crop destruction by the hemibiotrophic rice pathogen Magnaporthe oryzae requires plant defence suppression to facilitate extensive biotrophic growth in host cells before the onset of necrosis. How this is achieved at the genetic level is not well understood. Here, we report that a M. oryzae sirtuin, MoSir2, plays an essential role in rice defence suppression and colonization by controlling superoxide dismutase (SOD) gene expression. Loss of MoSir2 function in Δsir2 strains did not affect appressorial function, but biotrophic growth in rice cells was attenuated. Compared to wild type, Δsir2 strains failed to neutralize plant-derived reactive oxygen species (ROS) and elicited robust defence responses in rice epidermal cells that included elevated pathogenesis-related gene expression and granular depositions. Deletion of a SOD-encoding gene under MoSir2 control generated Δsod1 deletion strains that mimicked Δsir2 for impaired rice defence suppression, confirming SOD activity as a downstream output of MoSir2. In addition, comparative protein acetylation studies and forward genetic analyses identified a JmjC domain-containing protein as a likely target of MoSir2, and a Δsir2 Δjmjc double mutant was restored for MoSOD1 expression and defence suppression in rice epidermal cells. Together, this work reveals MoSir2 and MoJmjC as novel regulators of early rice cell infection.

  5. Rice-hull-fired power plant burns a nuisance waste, sells electricity, ash

    SciTech Connect

    Schwieger, B.

    1985-07-01

    Agrielectric Power Partners, Ltd., Lake Charles, LA, operate a 10.6 MW power plant fueled by rice hulls. The system is financially viable because PURPA regulations require the local utility to buy excess power from the producer. The installation also disposes of agricultural waste and process byproducts in an environmentally sound manner. The rice hulls are burned in a cyclonic effect boiler. Ash, which is 20% rice hulls on a dry basis, is finding markets as ladle and tundish insulation in the steel industry and as an absorbent for liquid waste spills.

  6. Different pathogenicities of Rice stripe virus from the insect vector and from viruliferous plants.

    PubMed

    Zhao, Wan; Yang, Pengcheng; Kang, Le; Cui, Feng

    2016-04-01

    Persistent plant viruses usually depend on insects for their transmission; they cannot be transmitted between plants or through mechanical inoculation. However, the mechanism by which persistent viruses become pathogenic in insect vectors remains unknown. In this study, we used Rice stripe virus (RSV), its insect vector Laodelphax striatellus and host plant (Oryza sativa) to explore how persistent viruses acquire pathogenicity from insect vectors. RSV acquired phytopathogenicity in both the alimentary tract and the salivary gland of L. striatellus. We mechanically inoculated RSV into rice O. sativa leaves through midrib microinjection. Insect-derived RSV induced a typical stripe symptom, whereas plant-derived RSV only produced chlorosis in rice leaves. Insect-derived RSV had higher expression of genes rdrp, ns2, nsvc2, sp and nsvc4 than plant-derived RSV, and the latter had higher expression of genes cp and ns3 than the former in rice leaves. Different from plant-derived RSV, insect-derived RSV damaged grana stacks within the chloroplast and inhibited photosynthesis by suppressing the photosystem II subunit psbp. This study not only presented a convenient method to mechanically inoculate RSV into plants, but also provided insights into the different pathogenic mechanisms of RSV from the insect vector and from viruliferous plants. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  7. Cyanobacteria-mediated phenylpropanoids and phytohormones in rice (Oryza sativa) enhance plant growth and stress tolerance.

    PubMed

    Singh, Dhananjaya P; Prabha, Ratna; Yandigeri, Mahesh S; Arora, Dilip K

    2011-11-01

    Phenylpropanoids, flavonoids and plant growth regulators in rice (Oryza sativa) variety (UPR 1823) inoculated with different cyanobacterial strains namely Anabaena oryzae, Anabaena doliolum, Phormidium fragile, Calothrix geitonos, Hapalosiphon intricatus, Aulosira fertilissima, Tolypothrix tenuis, Oscillatoria acuta and Plectonema boryanum were quantified using HPLC in pot conditions after 15 and 30 days. Qualitative analysis of the induced compounds using reverse phase HPLC and further confirmation with LC-MS/MS showed consistent accumulation of phenolic acids (gallic, gentisic, caffeic, chlorogenic and ferulic acids), flavonoids (rutin and quercetin) and phytohormones (indole acetic acid and indole butyric acid) in rice leaves. Plant growth promotion (shoot, root length and biomass) was positively correlated with total protein and chlorophyll content of leaves. Enzyme activity of peroxidase and phenylalanine ammonia lyase and total phenolic content was fairly high in rice leaves inoculated with O. acuta and P. boryanum after 30 days. Differential systemic accumulation of phenylpropanoids in plant leaves led us to conclude that cyanobacterial inoculation correlates positively with plant growth promotion and stress tolerance in rice. Furthermore, the study helped in deciphering possible mechanisms underlying plant growth promotion and stress tolerance in rice following cyanobacterial inoculation and indicated the less explored avenue of cyanobacterial colonization in stress tolerance against abiotic stress.

  8. Evaluating Leaf and Canopy Reflectance of Stressed Rice Plants to Monitor Arsenic Contamination

    PubMed Central

    Bandaru, Varaprasad; Daughtry, Craig S.; Codling, Eton E.; Hansen, David J.; White-Hansen, Susan; Green, Carrie E.

    2016-01-01

    Arsenic contamination is a serious problem in rice cultivated soils of many developing countries. Hence, it is critical to monitor and control arsenic uptake in rice plants to avoid adverse effects on human health. This study evaluated the feasibility of using reflectance spectroscopy to monitor arsenic in rice plants. Four arsenic levels were induced in hydroponically grown rice plants with application of 0, 5, 10 and 20 µmol·L−1 sodium arsenate. Reflectance spectra of upper fully expanded leaves were acquired over visible and infrared (NIR) wavelengths. Additionally, canopy reflectance for the four arsenic levels was simulated using SAIL (Scattering by Arbitrarily Inclined Leaves) model for various soil moisture conditions and leaf area indices (LAI). Further, sensitivity of various vegetative indices (VIs) to arsenic levels was assessed. Results suggest that plants accumulate high arsenic amounts causing plant stress and changes in reflectance characteristics. All leaf spectra based VIs related strongly with arsenic with coefficient of determination (r2) greater than 0.6 while at canopy scale, background reflectance and LAI confounded with spectral signals of arsenic affecting the VIs’ performance. Among studied VIs, combined index, transformed chlorophyll absorption reflectance index (TCARI)/optimized soil adjusted vegetation index (OSAVI) exhibited higher sensitivity to arsenic levels and better resistance to soil backgrounds and LAI followed by red edge based VIs (modified chlorophyll absorption reflectance index (MCARI) and TCARI) suggesting that these VIs could prove to be valuable aids for monitoring arsenic in rice fields. PMID:27322304

  9. Evaluating Leaf and Canopy Reflectance of Stressed Rice Plants to Monitor Arsenic Contamination.

    PubMed

    Bandaru, Varaprasad; Daughtry, Craig S; Codling, Eton E; Hansen, David J; White-Hansen, Susan; Green, Carrie E

    2016-06-18

    Arsenic contamination is a serious problem in rice cultivated soils of many developing countries. Hence, it is critical to monitor and control arsenic uptake in rice plants to avoid adverse effects on human health. This study evaluated the feasibility of using reflectance spectroscopy to monitor arsenic in rice plants. Four arsenic levels were induced in hydroponically grown rice plants with application of 0, 5, 10 and 20 µmol·L(-1) sodium arsenate. Reflectance spectra of upper fully expanded leaves were acquired over visible and infrared (NIR) wavelengths. Additionally, canopy reflectance for the four arsenic levels was simulated using SAIL (Scattering by Arbitrarily Inclined Leaves) model for various soil moisture conditions and leaf area indices (LAI). Further, sensitivity of various vegetative indices (VIs) to arsenic levels was assessed. Results suggest that plants accumulate high arsenic amounts causing plant stress and changes in reflectance characteristics. All leaf spectra based VIs related strongly with arsenic with coefficient of determination (r²) greater than 0.6 while at canopy scale, background reflectance and LAI confounded with spectral signals of arsenic affecting the VIs' performance. Among studied VIs, combined index, transformed chlorophyll absorption reflectance index (TCARI)/optimized soil adjusted vegetation index (OSAVI) exhibited higher sensitivity to arsenic levels and better resistance to soil backgrounds and LAI followed by red edge based VIs (modified chlorophyll absorption reflectance index (MCARI) and TCARI) suggesting that these VIs could prove to be valuable aids for monitoring arsenic in rice fields.

  10. Physiological and growth response of rice plants (Oryza sativa L.) to Trichoderma spp. inoculants

    PubMed Central

    2014-01-01

    Trichoderma spp., a known beneficial fungus is reported to have several mechanisms to enhance plant growth. In this study, the effectiveness of seven isolates of Trichoderma spp. to promote growth and increase physiological performance in rice was evaluated experimentally using completely randomized design under greenhouse condition. This study indicated that all the Trichoderma spp. isolates tested were able to increase several rice physiological processes which include net photosynthetic rate, stomatal conductance, transpiration, internal CO2 concentration and water use efficiency. These Trichoderma spp. isolates were also able to enhance rice growth components including plant height, leaf number, tiller number, root length and root fresh weight. Among the Trichoderma spp. isolates, Trichoderma sp. SL2 inoculated rice plants exhibited greater net photosynthetic rate (8.66 μmolCO2 m−2 s−1), internal CO2 concentration (336.97 ppm), water use efficiency (1.15 μmoCO2/mmoH2O), plant height (70.47 cm), tiller number (12), root length (22.5 cm) and root fresh weight (15.21 g) compared to the plants treated with other Trichoderma isolates tested. We conclude that beneficial fungi can be used as a potential growth promoting agent in rice cultivation. PMID:24949276

  11. Expression of a plant defensin in rice confers resistance to fungal phytopathogens.

    PubMed

    Jha, Sanjay; Chattoo, Bharat B

    2010-06-01

    Transgenic rice (Oryza sativa L. cv. Pusa basmati 1), overexpressing the Rs-AFP2 defensin gene from the Raphanus sativus was generated by Agrobacterium tumefaciens-mediated transformation. Expression levels of Rs-AFP2 ranged from 0.45 to 0.53% of total soluble protein in transgenic plants. It was observed that constitutive expression of Rs-AFP2 suppresses the growth of Magnaporthe oryzae and Rhizoctonia solani by 77 and 45%, respectively. No effect on plant morphology was observed in the Rs-AFP2 expressing rice lines. The inhibitory activity of protein extracts prepared from leaves of Rs-AFP2 plants on the in vitro growth of M. oryzae indicated that the Rs-AFP2 protein produced by transgenic rice plants was biologically active. Transgene expression of Rs-AFP2 was not accompanied by an induction of pathogenesis-related (PR) gene expression, suggesting that the expression of Rs-AFP2 directly inhibits the pathogens. Here, we demonstrate that transgenic rice plants expressing the Rs-AFP2 gene show enhanced resistance to M. oryzae and R. solani, two of the most important pathogens of rice.

  12. Growth and Productivity Response of Hybrid Rice to Application of Animal Manures, Plant Residues and Phosphorus

    PubMed Central

    Amanullah; Khan, Shams-ul-Tamraiz; Iqbal, Asif; Fahad, Shah

    2016-01-01

    The objective of this research was to evaluate the impact of organic sources (animal manures vs. plant residues at the rate of 10 t ha−1 each) on the productivity of hybrid rice (Oryza sativa L.) production under different levels of phosphorus (0, 30, 60, and 90 kg P ha−1) fertilization. Two separate field experiments were conducted. In experiment (1), impact of three animal manures sources (cattle, sheep, and poultry manures) and P levels were studied along with one control plot (no animal manure and P applied) was investigated. In experiment (2), three plant residues sources (peach leaves, garlic residues, and wheat straw) and P levels were studied along with one control plot (no plant residues and P applied). Both the experiments were carried out on small land farmer field at District Swabi, Khyber Pakhtunkhwa Province (Northwest Pakistan) during summer 2015. The results revealed that in both experiments the control plot had significantly (p ≤ 0.05) less productivity than the average of all treated plots with organic sources and P level. The increase in P levels in both experiments (animal manure vs. plant residues) resulted in higher rice productivity (90 > 60 > 30 > 0 kg P ha−1). In the experiment under animal manures, application of poultry manure increased rice productivity as compared with sheep and cattle manures (poultry > sheep > cattle manures). In the experiment under plant residues, application of peach leaves or garlic residues had higher rice productivity than wheat straw (peach leaves = garlic residues > wheat straw). On average, rice grown under animal manures produced about 20% higher grain yield than rice grown under crop residues. We conclude from this study that application of 90 kg P ha−1 along with combined application of animal manures, especially poultry manure increases rice productivity. Also, the use of either garlic residues or peach leaves, never applied before as organic manures, can increase crop productivity and will help

  13. Growth and Productivity Response of Hybrid Rice to Application of Animal Manures, Plant Residues and Phosphorus.

    PubMed

    Amanullah; Khan, Shams-Ul-Tamraiz; Iqbal, Asif; Fahad, Shah

    2016-01-01

    The objective of this research was to evaluate the impact of organic sources (animal manures vs. plant residues at the rate of 10 t ha(-1) each) on the productivity of hybrid rice (Oryza sativa L.) production under different levels of phosphorus (0, 30, 60, and 90 kg P ha(-1)) fertilization. Two separate field experiments were conducted. In experiment (1), impact of three animal manures sources (cattle, sheep, and poultry manures) and P levels were studied along with one control plot (no animal manure and P applied) was investigated. In experiment (2), three plant residues sources (peach leaves, garlic residues, and wheat straw) and P levels were studied along with one control plot (no plant residues and P applied). Both the experiments were carried out on small land farmer field at District Swabi, Khyber Pakhtunkhwa Province (Northwest Pakistan) during summer 2015. The results revealed that in both experiments the control plot had significantly (p ≤ 0.05) less productivity than the average of all treated plots with organic sources and P level. The increase in P levels in both experiments (animal manure vs. plant residues) resulted in higher rice productivity (90 > 60 > 30 > 0 kg P ha(-1)). In the experiment under animal manures, application of poultry manure increased rice productivity as compared with sheep and cattle manures (poultry > sheep > cattle manures). In the experiment under plant residues, application of peach leaves or garlic residues had higher rice productivity than wheat straw (peach leaves = garlic residues > wheat straw). On average, rice grown under animal manures produced about 20% higher grain yield than rice grown under crop residues. We conclude from this study that application of 90 kg P ha(-1) along with combined application of animal manures, especially poultry manure increases rice productivity. Also, the use of either garlic residues or peach leaves, never applied before as organic manures, can increase crop productivity and will help

  14. Rice ragged stunt virus-induced apoptosis affects virus transmission from its insect vector, the brown planthopper to the rice plant

    PubMed Central

    Huang, Hai-Jian; Bao, Yan-Yuan; Lao, Shu-Hua; Huang, Xiao-Hui; Ye, Yi-Zhou; Wu, Jian-Xiang; Xu, Hai-Jun; Zhou, Xue-Ping; Zhang, Chuan-Xi

    2015-01-01

    Most plant viruses that seriously damage agricultural crops are transmitted by insects. However, the mechanisms enabling virus transmission by insect vectors are poorly understood. The brown planthopper (Nilaparvata lugens) is one of the most serious rice pests, causing extensive damage to rice plants by sucking the phloem sap and transmitting viruses, including Rice ragged stunt virus (RRSV). In this study, we investigated the mechanisms of RRSV transmission from its insect vector to the rice plant in vivo using the terminal deoxynucleotidyl transferase dUTP nick-end labeling assay and RNA interference technology. RRSV induced apoptosis in the salivary gland cells of its insect vector, N. lugens. The RRSV-induced apoptosis was regulated through a caspase-dependent manner, and inhibition of the expression of N. lugens caspase-1 genes significantly interfered with virus transmission. Our findings establish a link between virus-associated apoptosis and virus transmission from the insect vector to the host plant. PMID:26073458

  15. Activity and distribution of methane-oxidizing bacteria in flooded rice soil microcosms and in rice plants (Oryza sativa)

    SciTech Connect

    Bosse, U.; Frenzel, P.

    1997-04-01

    Methane is an important greenhouse gas, and its atmospheric concentration has been increasing for decades. Flooded rice fields are one of the major sources of methane emissions to the atmosphere. These emissions are the net result of methane production by methanogenic bacteria in anoxic environments and methane oxidation by methane oxidizing bacteria in oxic environments. This study describes both the activity and distribution of methane oxidizing bacteria in microcosms used as a model for flooded rice fields. Then the process was characterized and localized, and finally the distribution of these organisms on the roots and culm, the size of the rhizosphere and the changes associated with plant age were examined. 59 refs., 8 figs., 2 tabs.

  16. Phenolic metabolism of Matricaria chamomilla plants exposed to nickel.

    PubMed

    Kovácik, Jozef; Klejdus, Borivoj; Backor, Martin

    2009-09-01

    We examined accumulation of phenolic acids, total soluble phenolics and flavonoids, and activities of phenolic metabolism-related enzymes (shikimate dehydrogenase (SKDH), phenylalanine ammonia-lyase (PAL), cinnamyl alcohol dehydrogenase (CAD), polyphenol oxidase (PPO)) in Matricaria chamomilla plants exposed to 3, 60 and 120 microM of nickel (Ni) for 10 days. Ni showed low toxicity as indicated by unaltered content of total soluble phenolics in the leaf rosettes. In the roots, the effects of Ni were more visible, including increased total phenolics and PAL activity, but a decrease in PPO activity was observed. CAD activity was not affected by any of the Ni concentrations. Cinnamic acid derivatives were affected more than benzoic acid derivatives. Accumulation of chlorogenic acid, an important antioxidant compound, was enhanced by Ni treatment (ca. 4-fold in 120 microM Ni). Accumulation of protocatechuic acid, a phenol with high chelating strength, even decreased in the leaf rosettes. These observations are discussed in connection to antioxidative properties of phenolic metabolites and previously tested metals (cadmium and copper).

  17. Sago-type palms were an important plant food prior to rice in southern subtropical China.

    PubMed

    Yang, Xiaoyan; Barton, Huw J; Wan, Zhiwei; Li, Quan; Ma, Zhikun; Li, Mingqi; Zhang, Dan; Wei, Jun

    2013-01-01

    Poor preservation of plant macroremains in the acid soils of southern subtropical China has hampered understanding of prehistoric diets in the region and of the spread of domesticated rice southwards from the Yangtze River region. According to records in ancient books and archaeological discoveries from historical sites, it is presumed that roots and tubers were the staple plant foods in this region before rice agriculture was widely practiced. But no direct evidences provided to test the hypothesis. Here we present evidence from starch and phytolith analyses of samples obtained during systematic excavations at the site of Xincun on the southern coast of China, demonstrating that during 3,350-2,470 aBC humans exploited sago palms, bananas, freshwater roots and tubers, fern roots, acorns, Job's-tears as well as wild rice. A dominance of starches and phytoliths from palms suggest that the sago-type palms were an important plant food prior to the rice in south subtropical China. We also believe that because of their reliance on a wide range of starch-rich plant foods, the transition towards labour intensive rice agriculture was a slow process.

  18. Sago-Type Palms Were an Important Plant Food Prior to Rice in Southern Subtropical China

    PubMed Central

    Yang, Xiaoyan; Barton, Huw J.; Wan, Zhiwei; Li, Quan; Ma, Zhikun; Li, Mingqi; Zhang, Dan; Wei, Jun

    2013-01-01

    Poor preservation of plant macroremains in the acid soils of southern subtropical China has hampered understanding of prehistoric diets in the region and of the spread of domesticated rice southwards from the Yangtze River region. According to records in ancient books and archaeological discoveries from historical sites, it is presumed that roots and tubers were the staple plant foods in this region before rice agriculture was widely practiced. But no direct evidences provided to test the hypothesis. Here we present evidence from starch and phytolith analyses of samples obtained during systematic excavations at the site of Xincun on the southern coast of China, demonstrating that during 3,350–2,470 aBC humans exploited sago palms, bananas, freshwater roots and tubers, fern roots, acorns, Job's-tears as well as wild rice. A dominance of starches and phytoliths from palms suggest that the sago-type palms were an important plant food prior to the rice in south subtropical China. We also believe that because of their reliance on a wide range of starch-rich plant foods, the transition towards labour intensive rice agriculture was a slow process. PMID:23667584

  19. Biochar amendment reduced methylmercury accumulation in rice plants.

    PubMed

    Shu, Rui; Wang, Yongjie; Zhong, Huan

    2016-08-05

    There is growing concern about methylmercury (MeHg) accumulation in rice grains and thus enhanced dietary exposure to MeHg in Asian countries. Here, we explored the possibility of reducing grain MeHg levels by biochar amendment, and the underlying mechanisms. Pot (i.e., rice cultivation in biochar amended soils) and batch experiments (i.e., incubation of amended soils under laboratory conditions) were carried out, to investigate MeHg dynamics (i.e., MeHg production, partitioning and phytoavailability in paddy soils, and MeHg uptake by rice) under biochar amendment (1-4% of soil mass). We demonstrate for the first time that biochar amendment could evidently reduce grain MeHg levels (49-92%). The declines could be attributed to the combined effects of: (1) increased soil MeHg concentrations, probably explained by the release of sulfate from biochar and thus enhanced microbial production of MeHg (e.g., by sulfate-reducing bacteria), (2) MeHg immobilization in soils, facilitated by the large surface areas and high organosulfur content of biochar, and (3) biodilution of MeHg in rice grains, due to the increased grain biomass under biochar amendment (35-79%). These observations together with mechanistic explanations improve understanding of MeHg dynamics in soil-rice systems, and support the possibility of reducing MeHg phytoaccumulation under biochar amendment.

  20. Circadian Variability in Methane Oxidation Activity in the Root Zone of Rice Plants

    NASA Astrophysics Data System (ADS)

    Schroth, M. H.; Cho, R.; Zeyer, J.

    2009-12-01

    Methane is an important greenhouse gas with a warming potential about 20 times stronger than that of carbon dioxide. A main source of biogenic methane are rice-paddy soils. Methane is produced in flooded rice fields under anaerobic conditions. Conversely, methanotrophic microorganisms oxidize methane to carbon dioxide in the root zone of rice plants in the presence of molecular oxygen supplied to the roots through the plants’ aerenchyma, thus reducing overall methane emissions to the atmosphere. To quantify methane oxidation we adapted push-pull tests (PPTs), a technique originally developed for aquifer testing, in combination with a suitable microbial inhibitor for application in the root zone of rice plants. During a PPT, 70 ml of a test solution containing dissolved substrates (methane, oxygen), nonreactive tracers (argon, chloride) and the methanogenesis inhibitor 2-Bromoethane sulfonate was injected into the plant’s root zone, and after a rest period of two hours extracted from the same location. Reaction rate constants were calculated from extraction-phase breakthrough curves of substrates and tracers. We conducted a set of three different laboratory PPTs to quantify methane oxidation at day time, directly after dawn, and at night in the root zone of four different potted rice plants each. High diurnal methane oxidation rate constants (up to 23 h-1) were obtained for all rice plants. Methane oxidation potential decreased soon after nightfall. At night, rate constants were usually below 1 h-1. Methane oxidation rates were apparently independent of additional oxygen supplied via the injected test solutions, but strongly dependent on photosynthetically produced oxygen transported to the roots through the plants’ aerenchyma. Additional PPTs utilizing 13C-labeled methane are currently being conducted to corroborate these findings. Ultimately, this novel tool shall support efforts to quantitatively understand the controlling mechanisms of methane turnover in

  1. No-tillage effects on N and P exports across a rice-planted watershed.

    PubMed

    Liang, Xinqiang; Wang, Zhibo; Zhang, Yixiang; Zhu, Chunyan; Lin, Limin; Xu, Lixian

    2016-05-01

    No tillage (NT) can be used as a management tool to alleviate the negative effects of agricultural practices on the environment by reducing the runoff volume and nutrient exports. The main objective of this research was to quantify the effect of NT on nitrogen (N) and phosphorus (P) exports across a rice-planted watershed using the soil and water assessment tool (SWAT) model. Results show that total N and P runoff exports from rice fields across the watershed ranged from 7.2 to 22.8 kg N/ha and 0.56 to 6.80 kg P/ha, respectively, over five rice-growing seasons under conventional tillage (CT) practice. The adoption of NT reduced the runoff volume, and the total N and total P exports by 25.9, 8.5, and 7.8 %, respectively, compared with the total exports under CT practice in the same study area. Rice yields were reduced by 0.7-1.9 % within the first 4 years after the adoption of NT, but began to rise in the fifth year. These results suggest that a long-term period of NT practice is necessary to reduce N and P exports without comprising the rice yield on rice-planted watersheds. In addition, the benefits of implementing NT practice alone were limited, and other practices, such as water and nutrient management, should be combined with NT practice.

  2. Arsenic uptake, accumulation and toxicity in rice plants: Possible remedies for its detoxification: A review.

    PubMed

    Bakhat, Hafiz Faiq; Zia, Zahida; Fahad, Shah; Abbas, Sunaina; Hammad, Hafiz Mohkum; Shahzad, Ahmad Naeem; Abbas, Farhat; Alharby, Hesham; Shahid, Muhammad

    2017-04-01

    Arsenic (As) is a toxic metalloid. Serious concerns have been raised in literature owing to its potential toxicity towards living beings. The metalloid causes various water- and food-borne diseases. Among food crops, rice contains the highest concentrations of As. Consuming As-contaminated rice results in serious health issues. Arsenic concentration in rice is governed by various factors in the rhizosphere such as availability and concentration of various mineral nutrients (iron, phosphate, sulfur and silicon) in soil solution, soil oxidation/reduction status, inter-conversion between organic and inorganic As compounds. Agronomic and civil engineering methods can be adopted to decrease As accumulation in rice. Agronomic methods such as improving soil porosity/aeration by irrigation management or creating the conditions favorable for As-precipitate formation, and decreasing As uptake and translocation by adding a inorganic nutrients that compete with As are easy and cost effective techniques at field scale. This review focuses on the factors regulating and competing As in soil-plant system and As accumulation in rice grains. Therefore, it is suggested that judicious use of water, management of soil, antagonistic effects of various inorganic plant-nutrients to As should be considered in rice cultivated areas to mitigate the building up of As in human food chain and with minimum negative impact to the environment.

  3. 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

  4. 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.

  5. Plant root transcriptome profiling reveals a strain-dependent response during Azospirillum-rice cooperation

    PubMed Central

    Drogue, Benoît; Sanguin, Hervé; Chamam, Amel; Mozar, Michael; Llauro, Christel; Panaud, Olivier; Prigent-Combaret, Claire; Picault, Nathalie; Wisniewski-Dyé, Florence

    2014-01-01

    Cooperation involving Plant Growth-Promoting Rhizobacteria results in improvements of plant growth and health. While pathogenic and symbiotic interactions are known to induce transcriptional changes for genes related to plant defense and development, little is known about the impact of phytostimulating rhizobacteria on plant gene expression. This study aims at identifying genes significantly regulated in rice roots upon Azospirillum inoculation, considering possible favored interaction between a strain and its original host cultivar. Genome-wide analyzes of Oryza sativa japonica cultivars Cigalon and Nipponbare were performed, by using microarrays, seven days post-inoculation with Azospirillum lipoferum 4B (isolated from Cigalon) or Azospirillum sp. B510 (isolated from Nipponbare) and compared to the respective non-inoculated condition. A total of 7384 genes were significantly regulated, which represent about 16% of total rice genes. A set of 34 genes is regulated by both Azospirillum strains in both cultivars, including a gene orthologous to PR10 of Brachypodium, and these could represent plant markers of Azospirillum-rice interactions. The results highlight a strain-dependent response of rice, with 83% of the differentially expressed genes being classified as combination-specific. Whatever the combination, most of the differentially expressed genes are involved in primary metabolism, transport, regulation of transcription and protein fate. When considering genes involved in response to stress and plant defense, it appears that strain B510, a strain displaying endophytic properties, leads to the repression of a wider set of genes than strain 4B. Individual genotypic variations could be the most important driving force of rice roots gene expression upon Azospirillum inoculation. Strain-dependent transcriptional changes observed for genes related to auxin and ethylene signaling highlight the complexity of hormone signaling networks in the Azospirillum-rice

  6. Plant root transcriptome profiling reveals a strain-dependent response during Azospirillum-rice cooperation.

    PubMed

    Drogue, Benoît; Sanguin, Hervé; Chamam, Amel; Mozar, Michael; Llauro, Christel; Panaud, Olivier; Prigent-Combaret, Claire; Picault, Nathalie; Wisniewski-Dyé, Florence

    2014-01-01

    Cooperation involving Plant Growth-Promoting Rhizobacteria results in improvements of plant growth and health. While pathogenic and symbiotic interactions are known to induce transcriptional changes for genes related to plant defense and development, little is known about the impact of phytostimulating rhizobacteria on plant gene expression. This study aims at identifying genes significantly regulated in rice roots upon Azospirillum inoculation, considering possible favored interaction between a strain and its original host cultivar. Genome-wide analyzes of Oryza sativa japonica cultivars Cigalon and Nipponbare were performed, by using microarrays, seven days post-inoculation with Azospirillum lipoferum 4B (isolated from Cigalon) or Azospirillum sp. B510 (isolated from Nipponbare) and compared to the respective non-inoculated condition. A total of 7384 genes were significantly regulated, which represent about 16% of total rice genes. A set of 34 genes is regulated by both Azospirillum strains in both cultivars, including a gene orthologous to PR10 of Brachypodium, and these could represent plant markers of Azospirillum-rice interactions. The results highlight a strain-dependent response of rice, with 83% of the differentially expressed genes being classified as combination-specific. Whatever the combination, most of the differentially expressed genes are involved in primary metabolism, transport, regulation of transcription and protein fate. When considering genes involved in response to stress and plant defense, it appears that strain B510, a strain displaying endophytic properties, leads to the repression of a wider set of genes than strain 4B. Individual genotypic variations could be the most important driving force of rice roots gene expression upon Azospirillum inoculation. Strain-dependent transcriptional changes observed for genes related to auxin and ethylene signaling highlight the complexity of hormone signaling networks in the Azospirillum-rice

  7. Non-destructive Assessment of Plant Nitrogen Parameters Using Leaf Chlorophyll Measurements in Rice

    PubMed Central

    Ata-Ul-Karim, Syed Tahir; Cao, Qiang; Zhu, Yan; Tang, Liang; Rehmani, Muhammad Ishaq Asif; Cao, Weixing

    2016-01-01

    Non-destructive assessment of plant nitrogen (N) status is essential for efficient crop production and N management in intensive rice (Oryza sativa L.) cropping systems. Chlorophyll meter (SPAD-502) has been widely used as a rapid, non-destructive and cost-effective diagnostic tool for in-season assessment of crop N status. The present study was intended to establish the quantitative relationships between chlorophyll meters readings, plant N concentration (PNC), N nutrition index (NNI), accumulated N deficit (AND), and N requirement (NR), as well as to compare the stability of these relationships at different vegetative growth stages in Japonica and Indica rice cultivars. Seven multi-locational field experiments using varied N rates and seven rice cultivars were conducted in east China. The results showed that the PNC and chlorophyll meters readings increased with increasing N application rates across the cultivars, growing seasons, and sites. The PNC and chlorophyll meters readings under varied N rates ranged from 2.29 to 3.21, 1.06 to 1.82 and 37.10 to 45.4 and 37.30 to 46.6, respectively, at TL and HD stages for Japonica rice cultivars, while they ranged from 2.25 to 3.23, 1.34 to 1.91 and 35.6 to 43.3 and 37.3 to 45.5 for Indica rice cultivars, respectively. The quantitative relationships between chlorophyll meters readings, PNC, NNI, AND, and NR established at different crop growth stages in two rice ecotypes, were highly significant with R2 values ranging from 0.69 to 0.93 and 0.71 to 0.86 for Japonica and Indica rice, respectively. The strongest relationships were observed for AND and NR at panicle initiation and booting stages in both rice ecotypes. The validation of the relationships developed in the present study with an independent data exhibited a solid model performance and confirmed their robustness as a reliable and rapid diagnostic tool for in-season estimation of plant N parameters for sustainable N management in rice. The results of this study

  8. Non-destructive Assessment of Plant Nitrogen Parameters Using Leaf Chlorophyll Measurements in Rice.

    PubMed

    Ata-Ul-Karim, Syed Tahir; Cao, Qiang; Zhu, Yan; Tang, Liang; Rehmani, Muhammad Ishaq Asif; Cao, Weixing

    2016-01-01

    Non-destructive assessment of plant nitrogen (N) status is essential for efficient crop production and N management in intensive rice (Oryza sativa L.) cropping systems. Chlorophyll meter (SPAD-502) has been widely used as a rapid, non-destructive and cost-effective diagnostic tool for in-season assessment of crop N status. The present study was intended to establish the quantitative relationships between chlorophyll meters readings, plant N concentration (PNC), N nutrition index (NNI), accumulated N deficit (AND), and N requirement (NR), as well as to compare the stability of these relationships at different vegetative growth stages in Japonica and Indica rice cultivars. Seven multi-locational field experiments using varied N rates and seven rice cultivars were conducted in east China. The results showed that the PNC and chlorophyll meters readings increased with increasing N application rates across the cultivars, growing seasons, and sites. The PNC and chlorophyll meters readings under varied N rates ranged from 2.29 to 3.21, 1.06 to 1.82 and 37.10 to 45.4 and 37.30 to 46.6, respectively, at TL and HD stages for Japonica rice cultivars, while they ranged from 2.25 to 3.23, 1.34 to 1.91 and 35.6 to 43.3 and 37.3 to 45.5 for Indica rice cultivars, respectively. The quantitative relationships between chlorophyll meters readings, PNC, NNI, AND, and NR established at different crop growth stages in two rice ecotypes, were highly significant with R(2) values ranging from 0.69 to 0.93 and 0.71 to 0.86 for Japonica and Indica rice, respectively. The strongest relationships were observed for AND and NR at panicle initiation and booting stages in both rice ecotypes. The validation of the relationships developed in the present study with an independent data exhibited a solid model performance and confirmed their robustness as a reliable and rapid diagnostic tool for in-season estimation of plant N parameters for sustainable N management in rice. The results of this study

  9. Heavy metal accumulation in rice plants. Effects on mineral nutrition and possible interaction of plant hormones

    SciTech Connect

    Rodrigo, M.; Martinez-Cortina, C.; Sanz, A. ); Escrig, I.; Lopez-Benet, F.J. )

    1993-05-01

    As a consequence of anthropogenic activities there is a constant increase in water and soil pollution by heavy metals, which may have negative effect on plants. We have studied the effects of Cd and Ni treatments on mineral nutrition of rice plants. six days after germination. Cd (0.1 mM) or Ni (0.5 mM) was added to the nutrient solution where the plants were grown. After 10 days mineral element contents were analyzed by atomic absorption spectrophotometry after sample digestion with nitric acid (70[degrees]C 24 h) in erlenmeyer flasks. Cd-treated plants accumulated high quantities of this metal (2.28 mg/g DW, 30 fold the value found in controls), and most of it remained in the root (66% of total). A great increase in Ni contents was also observed in Ni-treated plants (3.06 mg/g DW, 28 fold higher than in controls). However, contrary to Cd, Ni accumulated preferentially in shoots (81% of total). Addition of ABA or GA[sub 3] (5 mg/l) to the nutrient solution together with the heavy metal, did not affect Cd uptake by the plants but caused a significant reduction in Ni accumulation in the shoots (60%). In both, Cd- and Ni-treated plants, the uptake of divalent cations (Ca[sup 2][sup +], Mg[sup 2][sup +]) decreased more than 50% with respect to controls. This effect was not modified by hormonal applications, though a trend to reverse the decrease in Ca[sup 2][sup +] caused by Ni was observed.

  10. Population Growth and Characterization of Plant Injuries of Steneotarsonemus spinki Smiley (Acari: Tarsonemidae) on Rice.

    PubMed

    Jaimez-Ruiz, I A; Otero-Colina, G; Valdovinos-Ponce, G; Villanueva-Jiménez, J A; Vera-Graziano, J

    2015-06-01

    Rice is attacked by Steneotarsonemus spinki Smiley, a mite that has dispersed throughout many countries causing important loss on rice production. Rice plants of the variety Morelos A-92 were infested with S. spinki, and its population growth was estimated along plant development. Further, the morphological and histological injuries associated to the mite attack were characterized. The highest infestation level was obtained 13 weeks after plant infestation, with an average of 58.5 mites per plant, predominantly females. Morphological injuries were categorized from level 0 (no injuries from uninfested plants) to level 3, characterized by the highest injuries represented by blotches on the adaxial epidermis of the leaf sheath and on panicles and grains. Plants ranked within levels 0, 1, and 2 for morphological injury did not exhibit clear histological injuries, while those at level 3 exhibited histological injury characterized by destruction of cells of the adaxial epidermis, disorder, color change, and hypertrophy in the mesophyll cells, as well as color change in the abaxial epidermis. Thus, it presented a significant correlation between morphological injuries and mite density level, which can be further adopted to help the control decision-making process for this mite on rice.

  11. Physiological mechanisms underlying OsNAC5-dependent tolerance of rice plants to abiotic stress.

    PubMed

    Song, Shi-Yong; Chen, Ying; Chen, Jie; Dai, Xiao-Yan; Zhang, Wen-Hao

    2011-08-01

    To understand the functions of transcription factor OsNAC5 in response to abiotic stress, we generated transgenic rice plants with knockdown OsNAC5 by RNA-interfered (RNAi) and overexpressing OsNAC5, and investigated the effects of cold, drought and salt stress on wild-type (WT), RNAi and overexpression rice lines. Our results demonstrated that RNAi lines became less tolerant to these stresses than WT plants, while overexpression of OsNAC5 in Arabidopsis and rice enhanced tolerance to these stresses. The mechanisms underlying the changes in tolerance of the transgenic rice plants to abiotic stresses were explored by measuring free proline (Pro) and soluble sugar contents in WT and transgenic plants. Accumulation of Pro and soluble sugars was positively correlated with OsNAC5 expression levels. The less accumulation of Pro in RNAi lines may be accounted for by inhibition of Pro synthesis and transport at transcriptional levels. In addition, knockdown and overexpression of OsNAC5 enhanced and reduced accumulation of malondialdehyde and H(2)O(2), suggesting that knockdown of OsNAC5 renders RNAi plants more susceptible to oxidative damage. The RNAi lines displayed higher Na(+)/K(+) ratio due to greater accumulation of Na(+) ions than WT under salt stress conditions, and expression of genes encoding tonoplast Na(+)/H(+) antiporter was lower in RNAi lines than in WT under both control and salt-stressed conditions. Seed germination of RNAi and overexpression plants was more and less inhibited by salt and mannitol than that of WT, respectively. Seed germination of overexpression and RNAi plants was more and less sensitive than that of WT to ABA. These findings highlight the important role of OsNAC5 played in the tolerance of rice plants to abiotic stress by regulating downstream targets associated with accumulation of compatible solutes, Na(+) ions, H(2)O(2) and malondialdehyde.

  12. 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.

  13. 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.

  14. Do rice varieties have differences in their plant mineral nutrition?

    USDA-ARS?s Scientific Manuscript database

    As a first step, in 2007 and 2008, preliminary trials in both flooded and unflooded conditions were conducted on 1,643 rice varieties from more than 114 countries. These trials, conducted at the Texas AgriLife Research and Extension Center at Beaumont, identified differences in the mineral nutritio...

  15. F-box gene family is expanded in herbaceous annual plants Arabidopsis and rice relative to woody perennial plant Populus

    SciTech Connect

    Yang, Xiaohan; Kalluri, Udaya C; Jawdy, Sara; Gunter, Lee E; Yin, Tongming; Tschaplinski, Timothy J; Weston, David; Ranjan, Priya; Tuskan, Gerald A

    2008-01-01

    F-box proteins are generally responsible for substrate recognition in the Skp1-Cullin-F-box complexes that are involved in protein degradation via the ubiquitin-26S proteosome pathway. In plants, F-box genes influence a variety of biological processes such as leaf senescence, branching, self-incompatibility and responses to biotic and abiotic stresses. The number of F-box genes in Populus (~320) is less than half that found in Arabidopsis (~660) or rice (~680), even though the total number of genes in Populus is equivalent to that in rice and 1.5 times that in Arabidopsis. We performed comparative genomic analysis between the woody perennial plant Populus and the herbaceous annual plants Arabidopsis and rice in order to explicate the functional implications of this large gene family. Our analyses reveal interspecific differences in genomic distribution, orthologous relationship, intron evolution, protein domain structure and gene expression. The set of F-box genes shared by these three species appear to be involved in core biological processes essential for plant growth and development; lineage-specific differences primarily occurred because of an expansion of the F-box genes via tandem duplications in Arabidopsis and rice. The present study provides insights into the relationship between the structure and composition of the F-box gene family in herbaceous and woody species and their associated developmental and physiological features.

  16. Rice transgenic plants with suppressed expression of the β subunit of the heterotrimeric G protein.

    PubMed

    Utsunomiya, Yuzuko; Samejima, Chihiro; Fujisawa, Yukiko; Kato, Hisaharu; Iwasaki, Yukimoto

    2012-04-01

    The deficient mutant for the rice heterotrimeric G protein α subunit gene (RGA1), d1, showed dwarfism and set small seed due to a reduced cell number. Mutants for the rice heterotrimeric G protein β subunit gene (RGB1) have not been isolated. To determine the functions of RGB1, transgenic rice plants with suppressed expression of RGB1 were studied using the RNAi method. RGB1 knock-down lines showed browning of the lamina joint regions and nodes and reduced fertility, but these abnormality were not observed in d1. Transgenic plants in which the G protein β subunit was greatly decreased were not obtained, suggesting that the complete suppression of RGB1 mRNA may be lethal. In contrast, the d1 mutants, with complete loss of the G protein α subunit, were fertile and half the size of the WT. These studies suggest that RGB1 has different functions than RGA1.

  17. Rice transgenic plants with suppressed expression of the β subunit of the heterotrimeric G protein

    PubMed Central

    Utsunomiya, Yuzuko; Samejima, Chihiro; Fujisawa, Yukiko; Kato, Hisaharu; Iwasaki, Yukimoto

    2012-01-01

    The deficient mutant for the rice heterotrimeric G protein α subunit gene (RGA1), d1, showed dwarfism and set small seed due to a reduced cell number. Mutants for the rice heterotrimeric G protein β subunit gene (RGB1) have not been isolated. To determine the functions of RGB1, transgenic rice plants with suppressed expression of RGB1 were studied using the RNAi method. RGB1 knock-down lines showed browning of the lamina joint regions and nodes and reduced fertility, but these abnormality were not observed in d1. Transgenic plants in which the G protein β subunit was greatly decreased were not obtained, suggesting that the complete suppression of RGB1 mRNA may be lethal. In contrast, the d1 mutants, with complete loss of the G protein α subunit, were fertile and half the size of the WT. These studies suggest that RGB1 has different functions than RGA1. PMID:22499179

  18. Physiological and genotype-specific factors associated with grain quality changes in rice exposed to high ozone.

    PubMed

    Jing, Liquan; Dombinov, Vitalij; Shen, Shibo; Wu, Yanzhen; Yang, Lianxin; Wang, Yunxia; Frei, Michael

    2016-03-01

    Rising tropospheric ozone concentrations in Asia affect the yield and quality of rice. This study investigated ozone-induced changes in rice grain quality in contrasting rice genotypes, and explored the associated physiological processes during the reproductive growth phase. The ozone sensitive variety Nipponbare and a breeding line (L81) containing two tolerance QTLs in Nipponbare background were exposed to 100 ppb ozone (8 h per day) or control conditions throughout their growth. Ozone affected grain chalkiness and protein concentration and composition. The percentage of chalky grains was significantly increased in Nipponbare but not in L81. Physiological measurements suggested that grain chalkiness was associated with a drop in foliar carbohydrate and nitrogen levels during grain filling, which was less pronounced in the tolerant L81. Grain total protein concentration was significantly increased in the ozone treatment, although the albumin fraction (water soluble protein) decreased. The increase in protein was more pronounced in L81, due to increases in the glutelin fraction in this genotype. Amino acids responded differently to the ozone treatment. Three essential amino acids (leucine, methionine and threonine) showed significant increases, while seven showed significant treatment by genotype interactions, mostly due to more positive responses in L81. The trend of increased grain protein was in contrast to foliar nitrogen levels, which were negatively affected by ozone. A negative correlation between grain protein and foliar nitrogen in ozone stress indicated that higher grain protein cannot be explained by a concentration effect in all tissues due to lower biomass production. Rather, ozone exposure affected the nitrogen distribution, as indicated by altered foliar activity of the enzymes involved in nitrogen metabolism, such as glutamine synthetase and glutamine-2-oxoglutarate aminotransferase. Our results demonstrate differential responses of grain quality

  19. A technique system for the measurement, reconstruction and character extraction of rice plant architecture.

    PubMed

    Li, Xumeng; Wang, Xiaohui; Wei, Hailin; Zhu, Xinguang; Peng, Yulin; Li, Ming; Li, Tao; Huang, Huang

    2017-01-01

    This study developed a technique system for the measurement, reconstruction, and trait extraction of rice canopy architectures, which have challenged functional-structural plant modeling for decades and have become the foundation of the design of ideo-plant architectures. The system uses the location-separation-measurement method (LSMM) for the collection of data on the canopy architecture and the analytic geometry method for the reconstruction and visualization of the three-dimensional (3D) digital architecture of the rice plant. It also uses the virtual clipping method for extracting the key traits of the canopy architecture such as the leaf area, inclination, and azimuth distribution in spatial coordinates. To establish the technique system, we developed (i) simple tools to measure the spatial position of the stem axis and azimuth of the leaf midrib and to capture images of tillers and leaves; (ii) computer software programs for extracting data on stem diameter, leaf nodes, and leaf midrib curves from the tiller images and data on leaf length, width, and shape from the leaf images; (iii) a database of digital architectures that stores the measured data and facilitates the reconstruction of the 3D visual architecture and the extraction of architectural traits; and (iv) computation algorithms for virtual clipping to stratify the rice canopy, to extend the stratified surface from the horizontal plane to a general curved surface (including a cylindrical surface), and to implement in silico. Each component of the technique system was quantitatively validated and visually compared to images, and the sensitivity of the virtual clipping algorithms was analyzed. This technique is inexpensive and accurate and provides high throughput for the measurement, reconstruction, and trait extraction of rice canopy architectures. The technique provides a more practical method of data collection to serve functional-structural plant models of rice and for the optimization of rice

  20. A technique system for the measurement, reconstruction and character extraction of rice plant architecture

    PubMed Central

    Li, Xumeng; Wang, Xiaohui; Wei, Hailin; Zhu, Xinguang; Peng, Yulin; Li, Ming; Li, Tao; Huang, Huang

    2017-01-01

    This study developed a technique system for the measurement, reconstruction, and trait extraction of rice canopy architectures, which have challenged functional–structural plant modeling for decades and have become the foundation of the design of ideo-plant architectures. The system uses the location-separation-measurement method (LSMM) for the collection of data on the canopy architecture and the analytic geometry method for the reconstruction and visualization of the three-dimensional (3D) digital architecture of the rice plant. It also uses the virtual clipping method for extracting the key traits of the canopy architecture such as the leaf area, inclination, and azimuth distribution in spatial coordinates. To establish the technique system, we developed (i) simple tools to measure the spatial position of the stem axis and azimuth of the leaf midrib and to capture images of tillers and leaves; (ii) computer software programs for extracting data on stem diameter, leaf nodes, and leaf midrib curves from the tiller images and data on leaf length, width, and shape from the leaf images; (iii) a database of digital architectures that stores the measured data and facilitates the reconstruction of the 3D visual architecture and the extraction of architectural traits; and (iv) computation algorithms for virtual clipping to stratify the rice canopy, to extend the stratified surface from the horizontal plane to a general curved surface (including a cylindrical surface), and to implement in silico. Each component of the technique system was quantitatively validated and visually compared to images, and the sensitivity of the virtual clipping algorithms was analyzed. This technique is inexpensive and accurate and provides high throughput for the measurement, reconstruction, and trait extraction of rice canopy architectures. The technique provides a more practical method of data collection to serve functional–structural plant models of rice and for the optimization of rice

  1. Inhibition of ribonuclease and protease activities in arsenic exposed rice seedlings: role of proline as enzyme protectant.

    PubMed

    Mishra, Shruti; Dubey, Rama Shanker

    2006-09-01

    When seedlings of two rice (Oryza sativa L.) cvs. Malviya-36 and Pant-12 were raised under 25 and 50 microM As2O3 in the medium an increase in the level of RNA, proteins and proline accompanied with a decline in the level of free amino acid pool was observed under arsenic supplementation compared to controls. In situ As3+ treatment caused a marked inhibition in activities of ribonuclease (RNase, EC 3.1.27.1), protease and leucine aminopeptidase (LAP, EC 3.4.11.1) whereas the activity level of carboxypeptidase (EC 3.4.16.5) was enhanced. In vitro supply of As2O3 in the enzyme assay medium beyond 400 microM resulted in gradual inhibition of RNase and beyond 5 microM inhibition of LAP activities. Addition of 1M proline in the assay medium significantly restored the loss in RNase activity due to in vitro arsenic treatment or due to osmotic stress created by incorporation of polyethylene glycol (PEG). Isoform pattern of RNase extracted from As3+ -exposed seedlings showed a significant alteration compared to its pattern in unexposed seedlings. Results suggest that arsenic exposure impairs hydrolysis of RNA and proteins in rice seedlings due to inhibition of RNase and proteases activities and that proline accumulating under As3+ toxicity appears to serve as enzyme protectant.

  2. Genome-wide identification of DNA methylation provides insights into the association of gene expression in rice exposed to pesticide atrazine

    PubMed Central

    Lu, Yi Chen; Feng, Sheng Jun; Zhang, Jing Jing; Luo, Fang; Zhang, Shuang; Yang, Hong

    2016-01-01

    Atrazine (ATR) is a pesticide widely used for controlling weeds for crop production. Crop contamination with ATR negatively affects crop growth and development. This study presents the first genome-wide single-base-resolution maps of DNA methylation in ATR-exposed rice. Widespread differences were identified in CG and non-CG methylation marks between the ATR-exposed and ATR-free (control) rice. Most of DNA methyltransferases, histone methyltransferases and DNA demethylase were differentially regulated by ATR. We found more genes hypermethylated than those hypomethylated in the regions of upstream, genebody and downstream under ATR exposure. A stringent group of 674 genes (p < 0.05, two-fold change) with a strong preference of differential expression in ATR-exposed rice was identified. Some of the genes were identified in a subset of loss of function mutants defective in DNA methylation/demethylation. Provision of 5-azacytidine (AZA, inhibitor of DNA methylation) promoted the rice growth and reduced ATR content. By UPLC/Q-TOF-MS/MS, 8 degraded products and 9 conjugates of ATR in AZA-treated rice were characterized. Two of them has been newly identified in this study. Our data show that ATR-induced changes in DNA methylation marks are possibly involved in an epigenetic mechanism associated with activation of specific genes responsible for ATR degradation and detoxification. PMID:26739616

  3. Sucrose-mediated priming of plant defense responses and broad-spectrum disease resistance by overexpression of the maize pathogenesis-related PRms protein in rice plants.

    PubMed

    Gómez-Ariza, Jorge; Campo, Sonia; Rufat, Mar; Estopà, Montserrat; Messeguer, Joaquima; San Segundo, Blanca; Coca, María

    2007-07-01

    Expression of pathogenesis-related (PR) genes is part of the plant's natural defense response against pathogen attack. The PRms gene encodes a fungal-inducible PR protein from maize. Here, we demonstrate that expression of PRms in transgenic rice confers broad-spectrum protection against pathogens, including fungal (Magnaporthe oryzae, Fusarium verticillioides, and Helminthosporium oryzae) and bacterial (Erwinia chrysanthemi) pathogens. The PRms-mediated disease resistance in rice plants is associated with an enhanced capacity to express and activate the natural plant defense mechanisms. Thus, PRms rice plants display a basal level of expression of endogenous defense genes in the absence of the pathogen. PRms plants also exhibit stronger and quicker defense responses during pathogen infection. We also have found that sucrose accumulates at higher levels in leaves of PRms plants. Sucrose responsiveness of rice defense genes correlates with the pathogen-responsive priming of their expression in PRms rice plants. Moreover, pretreatment of rice plants with sucrose enhances resistance to M. oryzae infection. Together, these results support a sucrose-mediated priming of defense responses in PRms rice plants which results in broad-spectrum disease resistance.

  4. Soil and plant minerals associated with rice straighthead disorder induced by arsenic

    USDA-ARS?s Scientific Manuscript database

    Application of arsenic (As) as monosodium methanearsonate (MSMA) to soil has become the common practice for evaluation of rice straighthead, a physiological disorder. So far, no study has reported on soil mineral availability and plant mineral uptake as affected by the MSMA straighthead evaluation. ...

  5. Associations between host plant concentrations of selected biochemical nutrients and Mexican rice borer, Eoreuma loftini, infestation

    USDA-ARS?s Scientific Manuscript database

    The Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), is an economic pest of sugarcane and other graminaceous host crops, and it attacks grassy weeds. Oviposition preference has been known to be for plants with leaves that form folds. This study is the first to associate the nutr...

  6. Monitoring arsenic contamination in agricultural soils with reflectance spectroscopy of rice plants.

    PubMed

    Shi, Tiezhu; Liu, Huizeng; Wang, Junjie; Chen, Yiyun; Fei, Teng; Wu, Guofeng

    2014-06-03

    The objective of this study was to explore the feasibility and to investigate the mechanism for rapidly monitoring arsenic (As) contamination in agricultural soils with the reflectance spectra of rice plants. Several data pretreatment methods were applied to improve the prediction accuracy. The prediction of soil As contents was achieved by partial least-squares regression (PLSR) using laboratory and field spectra of rice plants, as well as linear regression employing normalized difference spectral index (NDSI) calculated from fild spectra. For laboratory spectra, the optimal PLSR model for predicting soil As contents was achieved using Savitzky-Golay smoothing (SG), first derivative and mean center (MC) (root-mean-square error of prediction (RMSEP)=14.7 mg kg(-1); r=0.64; residual predictive deviation (RPD)=1.31). For field spectra, the optimal PLSR model was also achieved using SG, first derivative and MC (RMSEP=13.7 mg kg(-1); r=0.71; RPD=1.43). In addition, the NDSI with 812 and 782 nm obtained a prediction accuracy with r=0.68, RMSEP=13.7 mg kg(-1), and RPD=1.36. These results indicated that it was feasible to monitor the As contamination in agricultural soils using the reflectance spectra of rice plants. The prediction mechanism might be the relationship between the As contents in soils and the chlorophyll-a/-b contents and cell structure in leaves or canopies of rice plants.

  7. 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.

  8. Different Bacterial Populations Associated with the Roots and Rhizosphere of Rice Incorporate Plant-Derived Carbon

    PubMed Central

    Hernández, Marcela; Yuan, Quan; Conrad, Ralf

    2015-01-01

    Microorganisms associated with the roots of plants have an important function in plant growth and in soil carbon sequestration. Rice cultivation is the second largest anthropogenic source of atmospheric CH4, which is a significant greenhouse gas. Up to 60% of fixed carbon formed by photosynthesis in plants is transported below ground, much of it as root exudates that are consumed by microorganisms. A stable isotope probing (SIP) approach was used to identify microorganisms using plant carbon in association with the roots and rhizosphere of rice plants. Rice plants grown in Italian paddy soil were labeled with 13CO2 for 10 days. RNA was extracted from root material and rhizosphere soil and subjected to cesium gradient centrifugation followed by 16S rRNA amplicon pyrosequencing to identify microorganisms enriched with 13C. Thirty operational taxonomic units (OTUs) were labeled and mostly corresponded to Proteobacteria (13 OTUs) and Verrucomicrobia (8 OTUs). These OTUs were affiliated with the Alphaproteobacteria, Betaproteobacteria, and Deltaproteobacteria classes of Proteobacteria and the “Spartobacteria” and Opitutae classes of Verrucomicrobia. In general, different bacterial groups were labeled in the root and rhizosphere, reflecting different physicochemical characteristics of these locations. The labeled OTUs in the root compartment corresponded to a greater proportion of the 16S rRNA sequences (∼20%) than did those in the rhizosphere (∼4%), indicating that a proportion of the active microbial community on the roots greater than that in the rhizosphere incorporated plant-derived carbon within the time frame of the experiment. PMID:25616793

  9. A Polyethylene Glycol-Mediated Protoplast Transformation System for Production of Fertile Transgenic Rice Plants 1

    PubMed Central

    Hayashimoto, Akio; Li, Zhijian; Murai, Norimoto

    1990-01-01

    We have established an efficient procedure for protoplast transformation and regeneration of fertile transgenic plants of rice (Oryza sativa L.) cultivars Nipponbare and Taipei 309. Protoplasts were mixed with a plant-expressible hygromycin resistance gene and treated with 25% (w/v) polyethylene glycol. Stringent selection of transformed colonies was applied to 14-day-old regenerated protoplasts in the presence of 95 micromolar of hygromycin B for 12 days. After selection, 450 and 200 resistant colonies were recovered per million treated Taipei 309 and Nipponbare protoplasts, respectively. Southern hybridization analysis of hygromycin-resistant cell lines and regenerated plants indicated that 1 to 10 copies of transferred DNA were integrated at 1 to 4 loci of the rice genome. Southern DNA analysis suggests that the introduced plasmid DNA may form concatemers by intermolecular recombination prior to integration. Four Taipei 309 and 39 Nipponbare transgenic rice plants were regenerated and grown to maturity in the greenhouse. Two Taipei 309 and 35 Nipponbare plants set viable seeds. Agronomic traits of Taipei 309 transgenic plants and inheritance of the hygromycin resistance trait by progeny of the selfed transgenic plants were analyzed. Images Figure 5 Figure 6 PMID:16667593

  10. Phytoremediation of the herbicides atrazine and metolachlor by transgenic rice plants expressing human CYP1A1, CYP2B6, and CYP2C19.

    PubMed

    Kawahigashi, Hiroyuki; Hirose, Sakiko; Ohkawa, Hideo; Ohkawa, Yasunobu

    2006-04-19

    This study evaluated the expression of human cytochrome P450 genes CYP1A1, CYP2B6, and CYP2C19 in rice plants (Oryza sativa cv. Nipponbare) introduced using the plasmid pIKBACH. The transgenic rice plants (pIKBACH rice plants) became more tolerant toward various herbicides than nontransgenic Nipponbare rice plants. Rice plants expressing pIKBACH grown in soil showed tolerance to the herbicides atrazine, metolachlor, and norflurazon and to a mixture of the three herbicides. The degradation of atrazine and metolachlor by pIKBACH rice plants was evaluated to confirm the metabolic activity of the introduced P450s. Although both pIKBACH and nontransgenic Nipponbare rice plants could decrease the amounts of the herbicides in plant tissue and culture medium, pIKBACH rice plants removed greater amounts in greenhouse experiments. The ability of pIKBACH rice plants to remove atrazine and metolachlor from soil was confirmed in large-scale experiments. The metabolism of herbicides by pIKBACH rice plants was enhanced by the introduced P450 species. Assuming that public and commercial acceptance is forthcoming, pIKBACH rice plants may become useful tools for the breeding of herbicide-tolerant crops and for phytoremediation of environmental pollution by organic chemicals.

  11. Mapping paddy rice planting area in wheat-rice double-cropped areas through integration of Landsat-8 OLI, MODIS, and PALSAR images

    NASA Astrophysics Data System (ADS)

    Wang, Jie; Xiao, Xiangming; Qin, Yuanwei; Dong, Jinwei; Zhang, Geli; Kou, Weili; Jin, Cui; Zhou, Yuting; Zhang, Yao

    2015-05-01

    As farmland systems vary over space and time (season and year), accurate and updated maps of paddy rice are needed for studies of food security and environmental problems. We selected a wheat-rice double-cropped area from fragmented landscapes along the rural-urban complex (Jiangsu Province, China) and explored the potential utility of integrating time series optical images (Landsat-8, MODIS) and radar images (PALSAR) in mapping paddy rice planting areas. We first identified several main types of non-cropland land cover and then identified paddy rice fields by selecting pixels that were inundated only during paddy rice flooding periods. These key temporal windows were determined based on MODIS Land Surface Temperature and vegetation indices. The resultant paddy rice map was evaluated using regions of interest (ROIs) drawn from multiple high-resolution images, Google Earth, and in-situ cropland photos. The estimated overall accuracy and Kappa coefficient were 89.8% and 0.79, respectively. In comparison with the National Land Cover Data (China) from 2010, the resultant map better detected changes in the paddy rice fields and revealed more details about their distribution. These results demonstrate the efficacy of using images from multiple sources to generate paddy rice maps for two-crop rotation systems.

  12. Mapping paddy rice planting area in wheat-rice double-cropped areas through integration of Landsat-8 OLI, MODIS, and PALSAR images

    PubMed Central

    Wang, Jie; Xiao, Xiangming; Qin, Yuanwei; Dong, Jinwei; Zhang, Geli; Kou, Weili; Jin, Cui; Zhou, Yuting; Zhang, Yao

    2015-01-01

    As farmland systems vary over space and time (season and year), accurate and updated maps of paddy rice are needed for studies of food security and environmental problems. We selected a wheat-rice double-cropped area from fragmented landscapes along the rural–urban complex (Jiangsu Province, China) and explored the potential utility of integrating time series optical images (Landsat-8, MODIS) and radar images (PALSAR) in mapping paddy rice planting areas. We first identified several main types of non-cropland land cover and then identified paddy rice fields by selecting pixels that were inundated only during paddy rice flooding periods. These key temporal windows were determined based on MODIS Land Surface Temperature and vegetation indices. The resultant paddy rice map was evaluated using regions of interest (ROIs) drawn from multiple high-resolution images, Google Earth, and in-situ cropland photos. The estimated overall accuracy and Kappa coefficient were 89.8% and 0.79, respectively. In comparison with the National Land Cover Data (China) from 2010, the resultant map better detected changes in the paddy rice fields and revealed more details about their distribution. These results demonstrate the efficacy of using images from multiple sources to generate paddy rice maps for two-crop rotation systems. PMID:25965027

  13. Seasonal changes in supercooling points and glycerol content in overwintering larvae of the asiatic rice borer from rice and water-oat plants.

    PubMed

    Hou, Maolin; Lin, Wei; Han, Yongqiang

    2009-08-01

    The Asiatic rice borer Chilo suppressalis (Walker) occurs mainly on rice Oryza sativa L. and water-oat Zizania latifolia (Turcz). Certain ecological and physiological differentiations between rice and water-oat populations have been shown. To determine whether there is host-associated differentiation in supercooling capacity, seasonal changes in supercooling points, glycerol content, and other physiological parameters of naturally occurring C. suppressalis larvae overwintering in rice and water-oat plants were compared over the winter. Supercooling points were low in the winter (November and December), significantly higher in March, and significantly lower in the water-oat population than in the rice population in the winter. Larvae from the water-oat population experienced a significant weight loss from December to March and were heavier than those from the rice population in the winter. Body water content (percentage of fresh weight) was low in the winter and increased significantly in March; no population differences were detected. Hemolymph glycerol content was high in the winter and dropped significantly in March; interpopulation differences were significant in December. Hemolymph trehalose content increased in the winter, and no population differences were detected. Whole body glucose and lipid content varied differently between the rice and the water-oat populations over the winter. It was found that variations in hemolymph glycerol content were responsible for the host-associated seasonal changes in supercooling capacity of overwintering larvae of the Asiatic rice borer.

  14. 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.

  15. Plant-parasitic nematode infections in rice: molecular and cellular insights.

    PubMed

    Kyndt, Tina; Fernandez, Diana; Gheysen, Godelieve

    2014-01-01

    Being one of the major staple foods in the world, and an interesting model monocot plant, rice (Oryza sativa L.) has recently received attention from molecular nematologists studying the cellular and molecular aspects of the interaction between this crop and plant-parasitic nematodes. In this review, we highlight recent advances in this field, with a focus on the best-studied root-knot nematodes. Histological studies have revealed the cellular changes inside root-knot nematode-induced feeding sites, both in the compatible interaction with Oryza sativa and the incompatible interaction with the related species Oryza glaberrima. After comparing the published data from transcriptome analyses, mutant studies, and exogenous hormone applications, we provide a comprehensive model showing the role and interaction of plant hormone pathways in defense of this monocot crop against root nematodes, where jasmonate seems to play a key role. Finally, recent evidence indicates that effectors secreted from rice-infecting nematodes can suppress plant defense.

  16. Overexpression of OsGATA12 regulates chlorophyll content, delays plant senescence and improves rice yield under high density planting.

    PubMed

    Lu, Guangwen; Casaretto, José A; Ying, Shan; Mahmood, Kashif; Liu, Fang; Bi, Yong-Mei; Rothstein, Steven J

    2017-05-01

    Agronomic traits controlling the formation, architecture and physiology of source and sink organs are main determinants of rice productivity. Semi-dwarf rice varieties with low tiller formation but high seed production per panicle and dark green and thick leaves with prolonged source activity are among the desirable traits to further increase the yield potential of rice. Here, we report the functional characterization of a zinc finger transcription factor, OsGATA12, whose overexpression causes increased leaf greenness, reduction of leaf and tiller number, and affects yield parameters. Reduced tillering allowed testing the transgenic plants under high density which resulted in significantly increased yield per area and higher harvest index compared to wild-type. We show that delayed senescence of transgenic plants and the corresponding longer stay-green phenotype is mainly due to increased chlorophyll and chloroplast number. Further, our work postulates that the increased greenness observed in the transgenic plants is due to more chlorophyll synthesis but most significantly to decreased chlorophyll degradation, which is supported by the reduced expression of genes involved in the chlorophyll degradation pathway. In particular we show evidence for the down-regulation of the STAY GREEN RICE gene and in vivo repression of its promoter by OsGATA12, which suggests a transcriptional repression function for a GATA transcription factor for prolonging the onset of senescence in cereals.

  17. Phylogenetic diversity of dominant bacterial and archaeal communities in plant-microbial fuel cells using rice plants.

    PubMed

    Ahn, Jae-Hyung; Jeong, Woo-Suk; Choi, Min-Young; Kim, Byung-Yong; Song, Jaekyeong; Weon, Hang-Yeon

    2014-12-28

    In this study, the phylogenetic diversities of bacterial and archaeal communities in a plantmicrobial fuel cell (P-MFC) were investigated together with the environmental parameters, affecting its performance by using rice as a model plant. The beneficial effect of the plant appeared only during a certain period of the rice-growing season, at which point the maximum power density was approximately 3-fold higher with rice plants. The temperature, electrical conductivity (EC), and pH in the cathodic and anodic compartments changed considerably during the rice-growing season, and a higher temperature, reduced difference in pH between the cathodic and anodic compartments, and higher EC were advantageous to the performance of the P-MFC. A 16S rRNA pyrosequencing analysis showed that the 16S rRNAs of Deltaproteobacteria and those of Gammaproteobacteria were enriched on the anodes and the cathodes, respectively, when the electrical circuit was connected. At the species level, the operational taxonomic units (OTUs) related to Rhizobiales, Geobacter, Myxococcus, Deferrisoma, and Desulfobulbus were enriched on the anodes, while an OTU related to Acidiferrobacter thiooxydans occupied the highest proportion on the cathodes and occurred only when the circuit was connected. Furthermore, the connection of the electrical circuit decreased the abundance of 16S rRNAs of acetotrophic methanogens and increased that of hydrogenotrophic methanogens. The control of these physicochemical and microbiological factors is expected to be able to improve the performance of P-MFCs.

  18. Significant accumulation of C(4)-specific pyruvate, orthophosphate dikinase in a C(3) plant, rice.

    PubMed

    Fukayama, H; Tsuchida, H; Agarie, S; Nomura, M; Onodera, H; Ono, K; Lee, B H; Hirose, S; Toki, S; Ku, M S; Makino, A; Matsuoka, M; Miyao, M

    2001-11-01

    The C(4)-Pdk gene encoding the C(4) enzyme pyruvate, orthophosphate dikinase (PPDK) of maize (Zea mays cv Golden Cross Bantam) was introduced into the C(3) plant, rice (Oryza sativa cv Kitaake). When the intact maize C(4)-Pdk gene, containing its own promoter and terminator sequences and exon/intron structure, was introduced, the PPDK activity in the leaves of some transgenic lines was greatly increased, in one line reaching 40-fold over that of wild-type plants. In a homozygous line, the PPDK protein accounted for 35% of total leaf-soluble protein or 16% of total leaf nitrogen. In contrast, introduction of a chimeric gene containing the full-length cDNA of the maize PPDK fused to the maize C(4)-Pdk promoter or the rice Cab promoter only increased PPDK activity and protein level slightly. These observations suggest that the intron(s) or the terminator sequence of the maize gene, or a combination of both, is necessary for high-level expression. In maize and transgenic rice plants carrying the intact maize gene, the level of transcript in the leaves per copy of the maize C(4)-Pdk gene was comparable, and the maize gene was expressed in a similar organ-specific manner. These results suggest that the maize C(4)-Pdk gene behaves in a quantitatively and qualitatively similar way in maize and transgenic rice plants. The activity of the maize PPDK protein expressed in rice leaves was light/dark regulated as it is in maize. This is the first reported evidence for the presence of an endogenous PPDK regulatory protein in a C(3) plant.

  19. Emission of biogenic sulfur gases from Chinese paddy soil and rice plant

    SciTech Connect

    Zhen Yang; Li Kong

    1996-12-31

    Biogenic sulfur gases emitted from terrestrial ecosystem may play in important role in global sulfur cycle and have a profound influence on global climate change. But very little is known concerning emissions from paddy soil and rice plant, which are abundant in many parts of the world. As a big agricultural country, this is about 33 million hectare rice planted in China. With laboratory incubation and closed chamber method in the field, the biogenic sulfur gases emitted from Chinese paddy soil and rice plant were detected in both conditions: hydrogen sulfide (H{sub 2}S), carbonyl sulfide (COS), methyl mercaptan (MSH), carbon disulfide (CS{sub 2}), dimethyl sulfide (DMS) and dimethyl disulfide (DMDS). Among which, DMS was predominant part of sulfur emission. Emission of sulfur gases from different paddy field exhibit high spatial and temporal variability. The application of fertilizer and organic manure, total sulfur content in wetland, air temperature were positively correlated to the emission of volatile sulfur gases from paddy soil. Diurnal and seasonal variation of total volatile sulfur gases and DMS indicate that their emissions were greatly influenced by the activity of the rice plant. The annual emission of total volatile sulfur gases, from Nanjing paddy field is ranged from 4.0 to 9.5 mg S m{sup -2}yr{sup -1}, that of DMS is ranged from 3.1 to 6.5 mg S m{sup -2}yr{sup -1}. Rice plant could absorb COS gas, that may be one of the sinks of COS.

  20. Using SPOT-5 images in rice farming for detecting BPH (Brown Plant Hopper)

    NASA Astrophysics Data System (ADS)

    Ghobadifar, F.; Wayayok, A.; Shattri, M.; Shafri, H.

    2014-06-01

    Infestation of rice plant-hopper such as Brown Plant Hopper (BPH) (Nilaparvata lugens) is one of the most notable risk in rice yield in tropical areas especially in Asia. In order to use visible and infrared images to detect stress in rice production caused by BPH infestation, several remote sensing techniques have been developed. Initial recognition of pest infestation by means of remote sensing will spreads, for precision farming practice. To address this issue, detection of sheath blight in rice farming was examined by using SPOT-5 images. Specific image indices such as Normalized decrease food production costs, limit environmental hazards, and enhance natural pest control before the problem Normalized Difference Vegetation Index (NDVI), Standard difference indices (SDI) and Ratio Vegetation Index (RVI) were used for analyses using ENVI 4.8 and SPSS software. Results showed that all the indices to recognize infected plants are significant at α = 0.01. Examination of the association between the disease indices indicated that band 3 (near infrared) and band 4 (mid infrared) have a relatively high correlation. The selected indices declared better association for detecting healthy plants from diseased ones. Consequently, these sorts of indices especially NDVI could be valued as indicators for developing techniques for detecting the sheath blight of rice by using remote sensing. This infers that they are useful for crop disease detection but the spectral resolution is probably not sufficient to distinguish plants with light infections (low severity level). Using the index as an indicator can clarify the threshold for zoning the outbreaks. Quick assessment information is very useful in precision farming to practice site specific management such as pesticide application.

  1. Temporal changes of radiocesium in irrigated paddy fields and its accumulation in rice plants in Fukushima.

    PubMed

    Yang, Baolu; Onda, Yuichi; Wakiyama, Yoshifumi; Yoshimura, Kazuya; Sekimoto, Hitoshi; Ha, Yiming

    2016-01-01

    About half of the total paddy field area, which is the dominant agricultural land in Fukushima Prefecture, was contaminated by radiocesium released by the Fukushima Daiichi Nuclear Power Plant accident. In this study, we investigated the temporal changes of radiocesium in soil, irrigation water, and rice plant in two adjacent rice paddies, with and without surface-soil-removal, in Fukushima Prefecture for over three years (2012-2014) after the nuclear accident. Our results showed that radiocesium migrated into 24-28 cm soil layers and that the activity concentration of radiocesium in paddy soils showed a significant reduction in 2014. The newly added radiocesium to paddies through irrigation water contributed only a maximum value of 0.15% and 0.75% of the total amount present in control and decontaminated paddies, respectively, throughout the study period. The radiocesium activity concentration in suspended sediment in irrigation water exponentially decreased, and the effective half-lives (Teff) for (137)Cs and (134)Cs were 1.3 and 0.9 years, respectively. Additionally, the average suspended sediment concentration in irrigation water increased between 2012 and 2014, suggesting that enhanced soil erosion had occurred in the surrounding environment. Radiocesium accumulation in rice plant also decreased with time in both paddies. However, the concentration ratio of radiocesium for rice plant in the decontaminated paddy increased compared with control paddy, despite approximately 96% of fallout radiocesium removed in paddy soil. Further analysis is required to clarify the reasons of high concentration ratio of radiocesium for rice plant in the decontaminated paddy.

  2. Endogenous salicylic acid protects rice plants from oxidative damage caused by aging as well as biotic and abiotic stress.

    PubMed

    Yang, Yinong; Qi, Min; Mei, Chuansheng

    2004-12-01

    Salicylic acid (SA) is a key endogenous signal that mediates defense gene expression and disease resistance in many dicotyledonous species. In contrast to tobacco and Arabidopsis, which contain low basal levels of SA, rice has two orders of magnitude higher levels of SA and appears to be insensitive to exogenous SA treatment. To determine the role of SA in rice plants, we have generated SA-deficient transgenic rice by expressing the bacterial salicylate hydroxylase that degrades SA. Depletion of high levels of endogenous SA in transgenic rice does not measurably affect defense gene expression, but reduces the plant's capacity to detoxify reactive oxygen intermediates (ROI). SA-deficient transgenic rice contains elevated levels of superoxide and H2O2, and exhibits spontaneous lesion formation in an age- and light-dependent manner. Exogenous application of SA analog benzothiadiazole complements SA deficiency and suppresses ROI levels and lesion formation. Although an increase of conjugated catechol was detected in SA-deficient rice, catechol does not appear to significantly affect ROI levels based on the endogenous catechol data and exogenous catechol treatment. When infected with the blast fungus (Magnaporthe grisea), SA-deficient rice exhibits increased susceptibility to oxidative bursts elicited by avirulent isolates. Furthermore, SA-deficient rice is hyperresponsive to oxidative damage caused by paraquat treatment. Taken together, our results strongly suggest that SA plays an important role to modulate redox balance and protect rice plants from oxidative stress.

  3. Transgenic rice plants ectopically expressing AtBAK1 are semi-dwarfed and hypersensitive to 24-epibrassinolide.

    PubMed

    Wang, Lei; Xu, Yun-yuan; Li, Jia; Powell, Rebecca A; Xu, Zhi-hong; Chong, Kang

    2007-05-01

    Brassinosteroids (BRs) are endogenous plant hormones essential for plant growth and development. Brassinosteroid insensitive1 (BRI1)-assocaiated receptor kinase (BAK1) is one of the key components in the BR signal transduction pathway due to its direct association with the BR receptor, BRI1. Although BRI1 and its orthologs have been identified from both dicotyledonous and monocotyledonous plants, less is known about BAK1 and its orthologs in higher plants other than Arabidopsis. This article provides the first piece of evidence that AtBAK1 can greatly affect growth and development of rice plants when ectopically expressed, suggesting that rice may share similar BR perception mechanism via BRI1/BAK1 complex. Interestingly, transgenic rice plants displayed semi-dwarfism and shortened primary roots. Physiological analysis and cell morphology assay demonstrated that the observed phenotypes in transgenic plants were presumably caused by hypersensitivity to endogenous levels of BRs, different from BR insensitive and deficient rice mutants. Consistently, several known BR inducible genes were also upregulated in transgenic rice plants, further suggesting that BAK1 was able to affect BR signaling in rice. On the other hand, the transgenic plants generated by overproducing AtBAK1 may potentially have agricultural applications because the dwarfed phenotype is generally resistant to lodging, while the fertility remains unaffected.

  4. Transgenic rice plants expressing human CYP1A1 remediate the triazine herbicides atrazine and simazine.

    PubMed

    Kawahigashi, Hiroyuki; Hirose, Sakiko; Ohkawa, Hideo; Ohkawa, Yasunobu

    2005-11-02

    The human cytochrome P450 CYP1A1 gene was introduced into rice plants (Oryza sativa cv. Nipponbare). One-month-old CYP1A1 plants grown in soil clearly showed a healthy growth and tolerance to 8.8 microM atrazine and 50 microM simazine, but nontransgenic plants were completely killed by the herbicides. Although transgenic and nontransgenic plants metabolized the two herbicides into the same sets of compounds, CYP1A1 plants metabolized atrazine and simazine more rapidly than did control plants. In small-scale experiments, residual amounts of atrazine and simazine in the culture medium of CYP1A1 plants were 43.4 and 12.3% of those in control medium; those of nontransgenic Nipponbare were 68.3 and 57.2%, respectively. When cultivated in soil with 2.95 microM atrazine and 3.15 microM simazine for 25 days, CYP1A1 plants eliminated 1.3 times more atrazine and 1.4 times more simazine from the soil than did control plants. Thus, CYP1A1 rice plants make it possible to remove atrazine and simazine more rapidly from the culture medium and soil than can nontransgenic Nipponbare.

  5. Pseudomonas-induced defence molecules in rice plants against leaffolder (Cnaphalocrocis medinalis) pest.

    PubMed

    Saravanakumar, Duraisamy; Muthumeena, Kannappan; Lavanya, Nallathambi; Suresh, Seetharaman; Rajendran, Lingan; Raguchander, Thiruvengadam; Samiyappan, Ramasamy

    2007-07-01

    Fluorescent pseudomonad strains Pf1, TDK1 and PY15 individually and in combination were evaluated against leaffolder, Cnaphalocrocis medinalis Guen., in rice under in vitro, glasshouse and field conditions. Among the various treatments used, a combination of Pf1, TDK1 and PY15 strains effectively reduced the incidence of leaffolder pest in rice plants to an extent comparable with chlorpyrifos-methyl. In addition, morphogenesis of the insect pest in all stages, larval, pupal and adult, was greatly affected by a combination of Pseudomonas Pf1, TDK1 and PY15 strains. Further, the induction of defence-related molecules was demonstrated. An increased accumulation of defence molecules such as chitinase and proteinase inhibitors was observed with a combined Pf1, TDK1 and PY15 treatment compared with all other treatments. Western blot analysis of chitinase revealed the extra induction of 18, 28 and 35 kDa isoforms in rice plants treated with a mixture of Pf1, TDK1 and PY15 strains against leaffolder pest. The study revealed that a combination of fluorescent pseudomonad strains affects the development of leaffolder pest by inducing defence molecules in rice plants which in turn enhance resistance to leaffolder attack.

  6. Optimizing rice plant photosynthate allocation reduces N2O emissions from paddy fields

    NASA Astrophysics Data System (ADS)

    Jiang, Yu; Huang, Xiaomin; Zhang, Xin; Zhang, Xingyue; Zhang, Yi; Zheng, Chengyan; Deng, Aixing; Zhang, Jun; Wu, Lianhai; Hu, Shuijin; Zhang, Weijian

    2016-07-01

    Rice paddies are a major source of anthropogenic nitrous oxide (N2O) emissions, especially under alternate wetting-drying irrigation and high N input. Increasing photosynthate allocation to the grain in rice (Oryza sativa L.) has been identified as an effective strategy of genetic and agronomic innovation for yield enhancement; however, its impacts on N2O emissions are still unknown. We conducted three independent but complementary experiments (variety, mutant study, and spikelet clipping) to examine the impacts of rice plant photosynthate allocation on paddy N2O emissions. The three experiments showed that N2O fluxes were significantly and negatively correlated with the ratio of grain yield to total aboveground biomass, known as the harvest index (HI) in agronomy (P < 0.01). Biomass accumulation and N uptake after anthesis were significantly and positively correlated with HI (P < 0.05). Reducing photosynthate allocation to the grain by spikelet clipping significantly increased white root biomass and soil dissolved organic C and reduced plant N uptake, resulting in high soil denitrification potential (P < 0.05). Our findings demonstrate that optimizing photosynthate allocation to the grain can reduce paddy N2O emissions through decreasing belowground C input and increasing plant N uptake, suggesting the potential for genetic and agronomic efforts to produce more rice with less N2O emissions.

  7. Tracking Se Assimilation and Speciation through the Rice Plant – Nutrient Competition, Toxicity and Distribution

    PubMed Central

    Eiche, Elisabeth; Riemann, Michael; Nick, Peter; Winkel, Lenny H. E.; Göttlicher, Jörg; Steininger, Ralph; Brendel, Rita; von Brasch, Matthias; Konrad, Gabriele; Neumann, Thomas

    2016-01-01

    Up to 1 billion people are affected by low intakes of the essential nutrient selenium (Se) due to low concentrations in crops. Biofortification of this micronutrient in plants is an attractive way of increasing dietary Se levels. We investigated a promising method of Se biofortification of rice seedlings, as rice is the primary staple for 3 billion people, but naturally contains low Se concentrations. We studied hydroponic Se uptake for 0–2500 ppb Se, potential phyto-toxicological effects of Se and the speciation of Se along the shoots and roots as a function of added Se species, concentrations and other nutrients supplied. We found that rice germinating directly in a Se environment increased plant-Se by factor 2–16, but that nutrient supplementation is required to prevent phyto-toxicity. XANES data showed that selenite uptake mainly resulted in the accumulation of organic Se in roots, but that selenate uptake resulted in accumulation of selenate in the higher part of the shoot, which is an essential requirement for Se to be transported to the grain. The amount of organic Se in the plant was positively correlated with applied Se concentration. Our results indicate that biofortification of seedlings with selenate is a successful method to increase Se levels in rice. PMID:27116220

  8. Optimizing rice plant photosynthate allocation reduces N2O emissions from paddy fields

    PubMed Central

    Jiang, Yu; Huang, Xiaomin; Zhang, Xin; Zhang, Xingyue; Zhang, Yi; Zheng, Chengyan; Deng, Aixing; Zhang, Jun; Wu, Lianhai; Hu, Shuijin; Zhang, Weijian

    2016-01-01

    Rice paddies are a major source of anthropogenic nitrous oxide (N2O) emissions, especially under alternate wetting-drying irrigation and high N input. Increasing photosynthate allocation to the grain in rice (Oryza sativa L.) has been identified as an effective strategy of genetic and agronomic innovation for yield enhancement; however, its impacts on N2O emissions are still unknown. We conducted three independent but complementary experiments (variety, mutant study, and spikelet clipping) to examine the impacts of rice plant photosynthate allocation on paddy N2O emissions. The three experiments showed that N2O fluxes were significantly and negatively correlated with the ratio of grain yield to total aboveground biomass, known as the harvest index (HI) in agronomy (P < 0.01). Biomass accumulation and N uptake after anthesis were significantly and positively correlated with HI (P < 0.05). Reducing photosynthate allocation to the grain by spikelet clipping significantly increased white root biomass and soil dissolved organic C and reduced plant N uptake, resulting in high soil denitrification potential (P < 0.05). Our findings demonstrate that optimizing photosynthate allocation to the grain can reduce paddy N2O emissions through decreasing belowground C input and increasing plant N uptake, suggesting the potential for genetic and agronomic efforts to produce more rice with less N2O emissions. PMID:27378420

  9. Genetic evidence for natural product mediated plant–plant allelopathy in rice

    PubMed Central

    Xu, Meimei; Galhano, Rita; Wiemann, Philipp; Bueno, Emilio; Tiernan, Mollie; Wu, William; Chung, Ill-Min; Gershenzon, Jonathan; Tudzynski, Bettina; Sesma, Ane; Peters, Reuben J.

    2011-01-01

    Summary A role for specific natural products in directly mediating antagonistic plant–plant interactions –that is, allelopathy –has been controversial. If proven, such phenomena would hold considerable promise for agronomic improvement of staple food crops such as rice (Oryza sativa).However, while substantiated by the presence of phytotoxic compounds at potentially relevant levels, demonstrating a direct role for specific natural products in allelopathy has been difficult due to the chemical complexity of root and plant litter exudates. This complexity can be bypassed via selective genetic manipulation to ablate production of putative allelopathic compounds, but such an approach previously has not been applied.The rice diterpenoid momilactones provide an example of natural products for which correlative biochemical evidence has been obtained for a role in allelopathy. Here, we apply reverse genetics, using knock-outs of the relevant diterpene synthases (OsCPS4 and OsKSL4), to demonstrate that rice momilactones are involved in allelopathy, including suppressing growth of the widespread rice paddy weed, barnyard grass (Echinochloa crus-galli).Thus, our results not only provide novel genetic evidence for natural product mediated allelopathy, but also furnish a molecular target for breeding and metabolic engineering of this important crop plant. PMID:22150231

  10. Plant/microbe cooperation for electricity generation in a rice paddy field.

    PubMed

    Kaku, Nobuo; Yonezawa, Natsuki; Kodama, Yumiko; Watanabe, Kazuya

    2008-05-01

    Soils are rich in organics, particularly those that support growth of plants. These organics are possible sources of sustainable energy, and a microbial fuel cell (MFC) system can potentially be used for this purpose. Here, we report the application of an MFC system to electricity generation in a rice paddy field. In our system, graphite felt electrodes were used; an anode was set in the rice rhizosphere, and a cathode was in the flooded water above the rhizosphere. It was observed that electricity generation (as high as 6 mW/m(2), normalized to the anode projection area) was sunlight dependent and exhibited circadian oscillation. Artificial shading of rice plants in the daytime inhibited the electricity generation. In the rhizosphere, rice roots penetrated the anode graphite felt where specific bacterial populations occurred. Supplementation to the anode region with acetate (one of the major root-exhausted organic compounds) enhanced the electricity generation in the dark. These results suggest that the paddy-field electricity-generation system was an ecological solar cell in which the plant photosynthesis was coupled to the microbial conversion of organics to electricity.

  11. Physiological and Molecular Basis of Susceptibility and Tolerance of Rice Plants to Complete Submergence

    PubMed Central

    JACKSON, MICHAEL B.; RAM, PHOOL C.

    2003-01-01

    Rice plants are much damaged by several days of total submergence. The effect can be a serious problem for rice farmers in the rainfed lowlands of Asia, and runs contrary to a widespread belief amongst plant biologists that rice is highly tolerant of submergence. This article assesses the characteristics of the underwater environment that may damage rice plants, examines various physiological mechanisms of injury, and reviews recent progress achieved using linkage mapping to locate quantitative traits loci (QTL) for tolerance inherited from a submergence‐tolerant cultivar FR13A. Progress towards identifying the gene(s) involved through physical mapping of a dominant tolerance locus on chromosome 9 is also summarized. Available physiological evidence points away from responses to oxygen shortage as being inextricably involved in submergence injury. An imbalance between production and consumption of assimilates is seen as being especially harmful, and is exacerbated by strongly accelerated leaf extension and leaf senescence that are ethylene‐mediated and largely absent from FR13A and related cultivars. DNA markers for a major QTL for tolerance are shown to be potentially useful in breeding programmes designed to improve submergence tolerance. PMID:12509343

  12. Tracking Se Assimilation and Speciation through the Rice Plant - Nutrient Competition, Toxicity and Distribution.

    PubMed

    Nothstein, Alexandra K; Eiche, Elisabeth; Riemann, Michael; Nick, Peter; Winkel, Lenny H E; Göttlicher, Jörg; Steininger, Ralph; Brendel, Rita; von Brasch, Matthias; Konrad, Gabriele; Neumann, Thomas

    2016-01-01

    Up to 1 billion people are affected by low intakes of the essential nutrient selenium (Se) due to low concentrations in crops. Biofortification of this micronutrient in plants is an attractive way of increasing dietary Se levels. We investigated a promising method of Se biofortification of rice seedlings, as rice is the primary staple for 3 billion people, but naturally contains low Se concentrations. We studied hydroponic Se uptake for 0-2500 ppb Se, potential phyto-toxicological effects of Se and the speciation of Se along the shoots and roots as a function of added Se species, concentrations and other nutrients supplied. We found that rice germinating directly in a Se environment increased plant-Se by factor 2-16, but that nutrient supplementation is required to prevent phyto-toxicity. XANES data showed that selenite uptake mainly resulted in the accumulation of organic Se in roots, but that selenate uptake resulted in accumulation of selenate in the higher part of the shoot, which is an essential requirement for Se to be transported to the grain. The amount of organic Se in the plant was positively correlated with applied Se concentration. Our results indicate that biofortification of seedlings with selenate is a successful method to increase Se levels in rice.

  13. ACC deaminase and IAA producing growth promoting bacteria from the rhizosphere soil of tropical rice plants.

    PubMed

    Bal, Himadri Bhusan; Das, Subhasis; Dangar, Tushar K; Adhya, Tapan K

    2013-12-01

    Beneficial plant-associated bacteria play a key role in supporting and/or promoting plant growth and health. Plant growth promoting bacteria present in the rhizosphere of crop plants can directly affect plant metabolism or modulate phytohormone production or degradation. We isolated 355 bacteria from the rhizosphere of rice plants grown in the farmers' fields in the coastal rice field soil from five different locations of the Ganjam district of Odisha, India. Six bacteria producing both ACC deaminase (ranging from 603.94 to 1350.02 nmol α-ketobutyrate mg(-1)  h(-1) ) and indole acetic acid (IAA; ranging from 10.54 to 37.65 μM ml(-1) ) in pure cultures were further identified using polyphasic taxonomy including BIOLOG((R)) , FAME analysis and the 16S rRNA gene sequencing. Phylogenetic analyses of the isolates resulted into five major clusters to include members of the genera Bacillus, Microbacterium, Methylophaga, Agromyces, and Paenibacillus. Seed inoculation of rice (cv. Naveen) by the six individual PGPR isolates had a considerable impact on different growth parameters including root elongation that was positively correlated with ACC deaminase activity and IAA production. The cultures also had other plant growth attributes including ammonia production and at least two isolates produced siderophores. Study indicates that presence of diverse rhizobacteria with effective growth-promoting traits, in the rice rhizosphere, may be exploited for a sustainable crop management under field conditions. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Annual Changes of Paddy Rice Planting Areas in Northeastern Asia from MODIS images in 2000-2014

    NASA Astrophysics Data System (ADS)

    Xiao, X.; Zhang, G.; Dong, J.; Menarguez, M. A.; Kou, W.; Jin, C.; Qin, Y.; Zhou, Y.; Wang, J.; Moore, B., III

    2014-12-01

    Knowledge of the area and spatial distribution of paddy rice is important for assessment of food security, management of water resources, estimation of greenhouse gas (methane) emissions, and understanding avian influenza virus transmission. Over the past two decades, paddy rice cultivation has expanded northward in temperate and cold temperate zones, particularly in Northeastern China. There is a need to quantify and map changes in paddy rice planting areas in Northeastern Asia (Japan, North and South Korea, and northeast China) at annual interval. We developed a pixel- and phenology-based image analysis system, MODIS-RICE, to map the paddy rice in Northeastern Asia by using multi-temporal MODIS thermal and surface reflectance imagery. Paddy rice fields during the flooding and transplanting phases have unique physical and spectral characteristics, which make it possible for the development of an automated and robust algorithm to track flooding and transplanting phases of paddy rice fields over time. In this presentation, we will show the MODIS-based annual maps of paddy rice planting area in the Northeastern Asia from 2000-2014 (500-m spatial resolution). Accuracy assessments using high-resolution images show that the resultant paddy rice map of Northeastern Asia had a comparable accuracy to the existing products, including 2010 Landsat-based National Land Cover Dataset (NLCD) of China, the 2010 RapidEye-based paddy rice map in North Korea, and the 2010 AVNIR-2-based National Land Cover Dataset in Japan in terms of both area and spatial pattern of paddy rice. This study has demonstrated that our novel MODIS-Rice system, which use both thermal and optical MODIS data over a year, are simple and robust tools to identify and map paddy rice fields in temperate and cold temperate zones.

  15. Microarray analysis reveals overlapping and specific transcriptional responses to different plant hormones in rice

    PubMed Central

    Garg, Rohini; Tyagi, Akhilesh K.; Jain, Mukesh

    2012-01-01

    Hormones exert pleiotropic effects on plant growth and development throughout the life cycle. Many of these effects are mediated at molecular level via altering gene expression. In this study, we investigated the exogenous effect of plant hormones, including auxin, cytokinin, abscisic acid, ethylene, salicylic acid and jasmonic acid, on the transcription of rice genes at whole genome level using microarray. Our analysis identified a total of 4171 genes involved in several biological processes, whose expression was altered significantly in the presence of different hormones. Further, 28% of these genes exhibited overlapping transcriptional responses in the presence of any two hormones, indicating crosstalk among plant hormones. In addition, we identified genes showing only a particular hormone-specific response, which can be used as hormone-specific markers. The results of this study will facilitate further studies in hormone biology in rice. PMID:22827941

  16. Plant regeneration methods for rapid generation of a large scale Ds transposant population in rice.

    PubMed

    Xuan, Yuan Hu; Huang, Jin; Yi, Gihwan; Park, Dong-Soo; Park, Soo Kwon; Eun, Moo Young; Yun, Doh Won; Lee, Gang-Seob; Kim, Tae Ho; Han, Chang-deok

    2013-01-01

    To mutagenize rice genomes, a two-element system is utilized. This system comprises an immobile Ac element driven by the CaMV 35S promoter, and a gene trap Ds carrying a partial intron with alternative splice acceptors fused to the GUS coding region. Rapid, large-scale generation of a Ds transposant population was achieved using a plant regeneration procedure involving the tissue culture of seed-derived calli carrying Ac and Ds elements. During tissue cultures, Ds mobility accompanies changes in methylation patterns of a terminal region of Ds, where over 70% of plants contained independent Ds insertions. In the transposon population, around 12% of plants expressed GUS at the early seedling stage. A flanking-sequence-tag (FST) database has been established by cloning over 19,968 Ds insertion sites and the Ds map shows relatively uniform distribution across the rice chromosomes.

  17. Assessment of water sources to plant growth in rice based cropping systems by stable water isotopes

    NASA Astrophysics Data System (ADS)

    Mahindawansha, Amani; Kraft, Philipp; Racela, Heathcliff; Breuer, Lutz

    2016-04-01

    Rice is one of the most water-consuming crops in the world. Understanding water source utilization of rice will help us to improve water use efficiency (WUE) in paddy management. The objectives of our study are to evaluate the isotopic compositions of surface ponded water, soil water, irrigation water, groundwater, rain water and plant water and based on stable water isotope signatures to evaluate the contributions of various water sources to plant growth (wet rice, aerobic rice and maize) together with investigating the contribution of water from different soil horizons for plant growth in different maturity periods during wet and dry seasons. Finally we will compare the water balances and crop yields in both crops during both seasons and calculate the water use efficiencies. This will help to identify the most efficient water management systems in rice based cropping ecosystems using stable water isotopes. Soil samples are collected from 9 different depths at up to 60 cm in vegetative, reproductive and matured periods of plant growth together with stem samples. Soil and plant samples are extracted by cryogenic vacuum extraction. Root samples are collected up to 60 cm depth from 10 cm intercepts leading calculation of root length density and dry weight. Groundwater, surface water, rain water and irrigation water are sampled weekly. All water samples are analyzed for hydrogen and oxygen isotope ratios (d18O and dD) using Los Gatos Research DLT100. Rainfall records, ground water level, surface water level fluctuations and the amount of water irrigated in each field will be measured during the sampling period. The direct inference approach which is based on comparing isotopic compositions (dD and d18O) between plant stem water and soil water will be used to determine water sources taken up by plant. Multiple-source mass balance assessment can provide the estimated range of potential contributions of water from each soil depth to root water uptake of a crop. These

  18. Plant physiological and soil characteristics associated with methane and nitrous oxide emission from rice paddy.

    PubMed

    Baruah, K K; Gogoi, Boby; Gogoi, P

    2010-01-01

    Methane (CH4) and nitrous oxide (N2O) are important greenhouse gases causing global warming and climate change. Efforts were made to analyze the CH4 and N2O flux in relation to plant and soil factors from rice (Oryza sativa L.) paddy. Ten popularly grown rice varieties namely Rashmisali, Bogajoha, Basmuthi, Lalkalamdani, Choimora (traditional varieties); Mahsuri, Moniram, Kushal, Gitesh and Profulla (high yielding varieties = HYV) were grown during monsoon season of July 2006. The CH4 and N2O emissions were measured the date of transplanting onwards at weekly interval along with soil and plant parameters. The seasonal integrated CH4 and N2O emission (Esif) from rice ranged from 8.13 g m(-2) to 13.00 g m(-2) and 121.63 mg N2O-N m(-2) to 189.46 mg N2O-N m(-2), respectively. Variety Gitesh emitted less N2O and CH4 amongst all the rice varieties. Both CH4 and N2O emission exhibited a significant positive correlation with leaf area, leaf number, tiller number and root dry weight. Soil organic carbon of the experimental field was associated with both CH4 and N2O emission whereas nitrate-N content of soil was associated with N2O emission. Methane emission showed significant positive correlations with soil temperature and crop photosynthetic rate. Traditional rice varieties with profuse vegetative growth recorded higher CH4 and N2O fluxes compared to HYVs. Gitesh and Kushal having low seasonal CH4 and N2O emission with higher yield potential can be recommended as low greenhouse gas emitting rice varieties.

  19. Precise plant height monitoring and biomass estimation with Terrestrial Laser Scanning in paddy rice

    NASA Astrophysics Data System (ADS)

    Tilly, N.; Hoffmeister, D.; Cao, Q.; Lenz-Wiedemann, V.; Miao, Y.; Bareth, G.

    2013-10-01

    Optimizing crop management is a major topic in the field of precision agriculture as the growing world population puts pressure on the efficiency of field production. Accordingly, methods to measure plant parameters with the needed precision and within-field resolution are required. Studies show that Terrestrial Laser Scanning (TLS) is a suitable method to capture small objects like crop plants. In this contribution, the results of multi-temporal surveys on paddy rice fields with the TLS system Riegl LMS-Z420i are presented. Three campaigns were carried out during the key vegetative stage of rice plants in the growing period 2012 to monitor the plant height. The TLS-derived point clouds are interpolated to visualize plant height above ground as crop surface models (CSMs) with a high resolution of 0.01 m. Spatio-temporal differences within the data of one campaign and between consecutive campaigns can be detected. The results were validated against manually measured plant heights with a high correlation (R2 = 0.71). Furthermore, the dependence of actual biomass from plant height was evaluated. To the present, no method for the non-destructive determination of biomass is found yet. Thus, plant parameters, like the height, have to be used for biomass estimations. The good correlation (R2 = 0.66) leads to the assumption that biomass can be estimated from plant height measurements. The results show that TLS can be considered as a very promising tool for precision agriculture.

  20. Expression and functional analysis of the plant-specific histone deacetylase HDT701 in rice

    PubMed Central

    Zhao, Jinhui; Zhang, Jianxia; Zhang, Wei; Wu, Kunlin; Zheng, Feng; Tian, Lining; Liu, Xuncheng; Duan, Jun

    2015-01-01

    Reversible histone acetylation and deacetylation at the N-terminus of histone tails play a crucial role in regulating eukaryotic gene activity. Acetylation of core histones is associated with gene activation, whereas deacetylation of histone is often correlated with gene repression. The level of histone acetylation is antagonistically catalyzed by histone acetyltransferases citation(HATs) and histone deacetylases (HDACs). In this work, we examined the subcellular localization, expression pattern and function of HDT701, a member of the plant-specific HD2-type histone deacetylase in rice. HDT701 is localized at the subcellular level in the nucleus. Histochemical GUS-staining analysis revealed that HDT701 is constitutively expressed throughout the life cycle of rice. Overexpression of HDT701 in rice decreases ABA, salt and osmotic stress resistance during seed germination. Delayed seed germination of HDT701 overexpression lines is associated with decreased histone H4 acetylation and down-regulated expression of GA biosynthetic genes. Moreover, overexpression of HDT701 in rice enhances salt and osmotic stress resistance during the seedling stage. Taken together, our findings suggested that HDT701 may play an important role in regulating seed germination in response to abiotic stresses in rice. PMID:25653654

  1. Plant Growth Promotion and Suppression of Bacterial Leaf Blight in Rice by Inoculated Bacteria

    PubMed Central

    Zaka, Abha; Imran, Asma; Zahid, Muhammad Awais; Yousaf, Sumaira; Rasul, Ghulam; Arif, Muhammad; Mirza, Muhammad Sajjad

    2016-01-01

    The present study was conducted to evaluate the potential of rice rhizosphere associated antagonistic bacteria for growth promotion and disease suppression of bacterial leaf blight (BLB). A total of 811 rhizospheric bacteria were isolated and screened against 3 prevalent strains of BLB pathogen Xanthomonas oryzae pv. oryzae (Xoo) of which five antagonistic bacteria, i.e., Pseudomonas spp. E227, E233, Rh323, Serratia sp. Rh269 and Bacillus sp. Rh219 showed antagonistic potential (zone of inhibition 1–19 mm). Production of siderophores was found to be the common biocontrol determinant and all the strains solubilized inorganic phosphate (82–116 μg mL-1) and produced indole acetic acid (0.48–1.85 mg L-1) in vitro. All antagonistic bacteria were non-pathogenic to rice, and their co-inoculation significantly improved plant health in terms of reduced diseased leaf area (80%), improved shoot length (31%), root length (41%) and plant dry weight (60%) as compared to infected control plants. Furthermore, under pathogen pressure, bacterial inoculation resulted in increased activity of defense related enzymes including phenylalanine ammonia-lyase and polyphenol oxidase, along with 86% increase in peroxidase and 53% increase in catalase enzyme activities in plants inoculated with Pseudomonas sp. Rh323 as well as co-inoculated plants. Bacterial strains showed good colonization potential in the rice rhizosphere up to 21 days after seed inoculation. Application of bacterial consortia in the field resulted in an increase of 31% in grain yield and 10% in straw yield over non-inoculated plots. Although, yield increase was statistically non-significant but was accomplished with overall saving of 20% chemical fertilizers. The study showed that Pseudomonas sp. Rh323 can be used to develop dual-purpose inoculum which can serve not only to suppress BLB but also to promote plant growth in rice. PMID:27532545

  2. Plant Growth Promotion and Suppression of Bacterial Leaf Blight in Rice by Inoculated Bacteria.

    PubMed

    Yasmin, Sumera; Zaka, Abha; Imran, Asma; Zahid, Muhammad Awais; Yousaf, Sumaira; Rasul, Ghulam; Arif, Muhammad; Mirza, Muhammad Sajjad

    2016-01-01

    The present study was conducted to evaluate the potential of rice rhizosphere associated antagonistic bacteria for growth promotion and disease suppression of bacterial leaf blight (BLB). A total of 811 rhizospheric bacteria were isolated and screened against 3 prevalent strains of BLB pathogen Xanthomonas oryzae pv. oryzae (Xoo) of which five antagonistic bacteria, i.e., Pseudomonas spp. E227, E233, Rh323, Serratia sp. Rh269 and Bacillus sp. Rh219 showed antagonistic potential (zone of inhibition 1-19 mm). Production of siderophores was found to be the common biocontrol determinant and all the strains solubilized inorganic phosphate (82-116 μg mL-1) and produced indole acetic acid (0.48-1.85 mg L-1) in vitro. All antagonistic bacteria were non-pathogenic to rice, and their co-inoculation significantly improved plant health in terms of reduced diseased leaf area (80%), improved shoot length (31%), root length (41%) and plant dry weight (60%) as compared to infected control plants. Furthermore, under pathogen pressure, bacterial inoculation resulted in increased activity of defense related enzymes including phenylalanine ammonia-lyase and polyphenol oxidase, along with 86% increase in peroxidase and 53% increase in catalase enzyme activities in plants inoculated with Pseudomonas sp. Rh323 as well as co-inoculated plants. Bacterial strains showed good colonization potential in the rice rhizosphere up to 21 days after seed inoculation. Application of bacterial consortia in the field resulted in an increase of 31% in grain yield and 10% in straw yield over non-inoculated plots. Although, yield increase was statistically non-significant but was accomplished with overall saving of 20% chemical fertilizers. The study showed that Pseudomonas sp. Rh323 can be used to develop dual-purpose inoculum which can serve not only to suppress BLB but also to promote plant growth in rice.

  3. Arabidopsis thaliana: A Model Host Plant to Study Plant-Pathogen Interaction Using Rice False Smut Isolates of Ustilaginoidea virens.

    PubMed

    Andargie, Mebeaselassie; Li, Jianxiong

    2016-01-01

    Rice false smut fungus which is a biotrophic fungal pathogen causes an important rice disease and brings a severe damage where rice is cultivated. We established a new fungal-plant pathosystem where Ustilaginoidea virens was able to interact compatibly with the model plant Arabidopsis thaliana. Disease symptoms were apparent on the leaves of the plants after 6 days of post inoculation in the form of chlorosis. Cytological studies showed that U. virens caused a heavy infestation inside the cells of the chlorotic tissues. Development and colonization of aerial mycelia in association with floral organ, particularly on anther and stigma of the flowers after 3 weeks of post inoculation was evident which finally caused infection on the developing seeds and pod tissues. The fungus adopts a uniquely biotrophic infection strategy in roots and spreads without causing a loss of host cell viability. We have also demonstrated that U. virens isolates infect Arabidopsis and the plant subsequently activates different defense response mechanisms which are witnessed by the expression of pathogenesis-related genes, PR-1, PR-2, PR-5, PDF1.1, and PDF1.2. The established A. thaliana-U. virens pathosystem will now permit various follow-up molecular genetics and gene expression experiments to be performed to identify the defense signals and responses that restrict fungal hyphae colonization in planta and also provide initial evidence for tissue-adapted fungal infection strategies.

  4. Loose Plant Architecture1, an INDETERMINATE DOMAIN protein involved in shoot gravitropism, regulates plant architecture in rice.

    PubMed

    Wu, Xinru; Tang, Ding; Li, Ming; Wang, Kejian; Cheng, Zhukuan

    2013-01-01

    Tiller angle and leaf angle are two important components of rice (Oryza sativa) plant architecture that play a crucial role in determining grain yield. Here, we report the cloning and characterization of the Loose Plant Architecture1 (LPA1) gene in rice, the functional ortholog of the AtIDD15/SHOOT GRAVITROPISM5 (SGR5) gene in Arabidopsis (Arabidopsis thaliana). LPA1 regulates tiller angle and leaf angle by controlling the adaxial growth of tiller node and lamina joint. LPA1 was also found to affect shoot gravitropism. Expression pattern analysis suggested that LPA1 influences plant architecture by affecting the gravitropism of leaf sheath pulvinus and lamina joint. However, LPA1 only influences gravity perception or signal transduction in coleoptile gravitropism by regulating the sedimentation rate of amyloplasts, distinct from the actions of LAZY1. LPA1 encodes a plant-specific INDETERMINATE DOMAIN protein and defines a novel subfamily of 28 INDETERMINATE DOMAIN proteins with several unique conserved features. LPA1 is localized in the nucleus and functions as an active transcriptional repressor, an activity mainly conferred by a conserved ethylene response factor-associated amphiphilic repression-like motif. Further analysis suggests that LPA1 participates in a complicated transcriptional and protein interaction network and has evolved novel functions distinct from SGR5. This study not only facilitates the understanding of gravitropism mechanisms but also generates a useful genetic material for rice breeding.

  5. Loose Plant Architecture1, an INDETERMINATE DOMAIN Protein Involved in Shoot Gravitropism, Regulates Plant Architecture in Rice1[W

    PubMed Central

    Wu, Xinru; Tang, Ding; Li, Ming; Wang, Kejian; Cheng, Zhukuan

    2013-01-01

    Tiller angle and leaf angle are two important components of rice (Oryza sativa) plant architecture that play a crucial role in determining grain yield. Here, we report the cloning and characterization of the Loose Plant Architecture1 (LPA1) gene in rice, the functional ortholog of the AtIDD15/SHOOT GRAVITROPISM5 (SGR5) gene in Arabidopsis (Arabidopsis thaliana). LPA1 regulates tiller angle and leaf angle by controlling the adaxial growth of tiller node and lamina joint. LPA1 was also found to affect shoot gravitropism. Expression pattern analysis suggested that LPA1 influences plant architecture by affecting the gravitropism of leaf sheath pulvinus and lamina joint. However, LPA1 only influences gravity perception or signal transduction in coleoptile gravitropism by regulating the sedimentation rate of amyloplasts, distinct from the actions of LAZY1. LPA1 encodes a plant-specific INDETERMINATE DOMAIN protein and defines a novel subfamily of 28 INDETERMINATE DOMAIN proteins with several unique conserved features. LPA1 is localized in the nucleus and functions as an active transcriptional repressor, an activity mainly conferred by a conserved ethylene response factor-associated amphiphilic repression-like motif. Further analysis suggests that LPA1 participates in a complicated transcriptional and protein interaction network and has evolved novel functions distinct from SGR5. This study not only facilitates the understanding of gravitropism mechanisms but also generates a useful genetic material for rice breeding. PMID:23124325

  6. The bifunctional plant receptor, OsCERK1, regulates both chitin-triggered immunity and arbuscular mycorrhizal symbiosis in rice.

    PubMed

    Miyata, Kana; Kozaki, Toshinori; Kouzai, Yusuke; Ozawa, Kenjirou; Ishii, Kazuo; Asamizu, Erika; Okabe, Yoshihiro; Umehara, Yosuke; Miyamoto, Ayano; Kobae, Yoshihiro; Akiyama, Kohki; Kaku, Hanae; Nishizawa, Yoko; Shibuya, Naoto; Nakagawa, Tomomi

    2014-11-01

    Plants are constantly exposed to threats from pathogenic microbes and thus developed an innate immune system to protect themselves. On the other hand, many plants also have the ability to establish endosymbiosis with beneficial microbes such as arbuscular mycorrhizal (AM) fungi or rhizobial bacteria, which improves the growth of host plants. How plants evolved these systems managing such opposite plant-microbe interactions is unclear. We show here that knockout (KO) mutants of OsCERK1, a rice receptor kinase essential for chitin signaling, were impaired not only for chitin-triggered defense responses but also for AM symbiosis, indicating the bifunctionality of OsCERK1 in defense and symbiosis. On the other hand, a KO mutant of OsCEBiP, which forms a receptor complex with OsCERK1 and is essential for chitin-triggered immunity, established mycorrhizal symbiosis normally. Therefore, OsCERK1 but not chitin-triggered immunity is required for AM symbiosis. Furthermore, experiments with chimeric receptors showed that the kinase domains of OsCERK1 and homologs from non-leguminous, mycorrhizal plants could trigger nodulation signaling in legume-rhizobium interactions as the kinase domain of Nod factor receptor1 (NFR1), which is essential for triggering the nodulation program in leguminous plants, did. Because leguminous plants are believed to have developed the rhizobial symbiosis on the basis of AM symbiosis, our results suggest that the symbiotic function of ancestral CERK1 in AM symbiosis enabled the molecular evolution to leguminous NFR1 and resulted in the establishment of legume-rhizobia symbiosis. These results also suggest that OsCERK1 and homologs serve as a molecular switch that activates defense or symbiotic responses depending on the infecting microbes.

  7. Gene response in rice plants treated with continuous fog influenced by pH, was similar to that treated with biotic stress

    PubMed Central

    2014-01-01

    Background Throughout Asia, including Japan, rice plants are cultivated in a wide range of areas from lowlands to highlands and are frequently exposed to fog, including acid fog. Some physiological studies have shown that acid fog can be a stress factor for plants. We analyzed the gene expression profiles of rice plants treated with artificially prepared simulated acid fog (SiAF) or simulated neutral fog (SiNF) for 1 or 7 days. Results Microarray analysis results suggested that both the SiAF and the SiNF treatments induced the expression of genes involved in the defense and stress responses in rice plants. Induction of such genes was detected in plants treated with SiAF for 1 day, and the number of induced genes increased in plants treated with SiAF for 7 days. The genes for defense and stress responses were also induced by SiNF for 7 days, although they were not induced by SiNF for 1 day. The gene expression profiles of the SiAF-treated and the SiNF-treated plants were compared to those of plants treated with other stress factors. The comparison revealed that both SiAF and SiNF treatments have similar effects to biotic stresses and ozone stress. The genes encoding NADPH oxidase and germin, which function in apoplasts, were also induced by SiAF, SiNF and biotic stresses. Conclusions These findings suggest that both the SiAF and the SiNF treatments may result in oxidative stress through the apoplastic production of reactive oxygen species. PMID:24987489

  8. Ethnobotanical investigation of 'wild' food plants used by rice farmers in Kalasin, Northeast Thailand

    PubMed Central

    2011-01-01

    Background Wild food plants are a critical component in the subsistence system of rice farmers in Northeast Thailand. One of the important characteristics of wild plant foods among farming households is that the main collection locations are increasingly from anthropogenic ecosystems such as agricultural areas rather than pristine ecosystems. This paper provides selected results from a study of wild food conducted in several villages in Northeast Thailand. A complete botanical inventory of wild food plants from these communities and surrounding areas is provided including their diversity of growth forms, the different anthropogenic locations were these species grow and the multiplicity of uses they have. Methods Data was collected using focus groups and key informant interviews with women locally recognized as knowledgeable about contemporarily gathered plants. Plant species were identified by local taxonomists. Results A total of 87 wild food plants, belonging to 47 families were reported, mainly trees, herbs (terrestrial and aquatic) and climbers. Rice fields constitute the most important growth location where 70% of the plants are found, followed by secondary woody areas and home gardens. The majority of species (80%) can be found in multiple growth locations, which is partly explained by villagers moving selected species from one place to another and engaging in different degrees of management. Wild food plants have multiple edible parts varying from reproductive structures to vegetative organs. More than two thirds of species are reported as having diverse additional uses and more than half of them are also regarded as medicine. Conclusions This study shows the remarkable importance of anthropogenic areas in providing wild food plants. This is reflected in the great diversity of species found, contributing to the food and nutritional security of rice farmers in Northeast Thailand. PMID:22067578

  9. Ethnobotanical investigation of 'wild' food plants used by rice farmers in Kalasin, Northeast Thailand.

    PubMed

    Cruz-Garcia, Gisella S; Price, Lisa L

    2011-11-08

    Wild food plants are a critical component in the subsistence system of rice farmers in Northeast Thailand. One of the important characteristics of wild plant foods among farming households is that the main collection locations are increasingly from anthropogenic ecosystems such as agricultural areas rather than pristine ecosystems. This paper provides selected results from a study of wild food conducted in several villages in Northeast Thailand. A complete botanical inventory of wild food plants from these communities and surrounding areas is provided including their diversity of growth forms, the different anthropogenic locations were these species grow and the multiplicity of uses they have. Data was collected using focus groups and key informant interviews with women locally recognized as knowledgeable about contemporarily gathered plants. Plant species were identified by local taxonomists. A total of 87 wild food plants, belonging to 47 families were reported, mainly trees, herbs (terrestrial and aquatic) and climbers. Rice fields constitute the most important growth location where 70% of the plants are found, followed by secondary woody areas and home gardens. The majority of species (80%) can be found in multiple growth locations, which is partly explained by villagers moving selected species from one place to another and engaging in different degrees of management. Wild food plants have multiple edible parts varying from reproductive structures to vegetative organs. More than two thirds of species are reported as having diverse additional uses and more than half of them are also regarded as medicine. This study shows the remarkable importance of anthropogenic areas in providing wild food plants. This is reflected in the great diversity of species found, contributing to the food and nutritional security of rice farmers in Northeast Thailand.

  10. Transgenerational epimutations induced by multi-generation drought imposition mediate rice plant's adaptation to drought condition.

    PubMed

    Zheng, Xiaoguo; Chen, Liang; Xia, Hui; Wei, Haibin; Lou, Qiaojun; Li, Mingshou; Li, Tiemei; Luo, Lijun

    2017-01-04

    Epigenetic mechanisms are crucial mediators of appropriate plant reactions to adverse environments, but their involvement in long-term adaptation is less clear. Here, we established two rice epimutation accumulation lines by applying drought conditions to 11 successive generations of two rice varieties. We took advantage of recent technical advances to examine the role of DNA methylation variations on rice adaptation to drought stress. We found that multi-generational drought improved the drought adaptability of offspring in upland fields. At single-base resolution, we discovered non-random appearance of drought-induced epimutations. Moreover, we found that a high proportion of drought-induced epimutations maintained their altered DNA methylation status in advanced generations. In addition, genes related to transgenerational epimutations directly participated in stress-responsive pathways. Analysis based on a cluster of drought-responsive genes revealed that their DNA methylation patterns were affected by multi-generational drought. These results suggested that epigenetic mechanisms play important roles in rice adaptations to upland growth conditions. Epigenetic variations have morphological, physiological and ecological consequences and are heritable across generations, suggesting that epigenetics can be considered an important regulatory mechanism in plant long-term adaptation and evolution under adverse environments.

  11. Eliminating aluminum toxicity in an acid sulfate soil for rice cultivation using plant growth promoting bacteria.

    PubMed

    Panhwar, Qurban Ali; Naher, Umme Aminun; Radziah, Othman; Shamshuddin, Jusop; Razi, Ismail Mohd

    2015-02-20

    Aluminum toxicity is widely considered as the most important limiting factor for plants growing in acid sulfate soils. A study was conducted in laboratory and in field to ameliorate Al toxicity using plant growth promoting bacteria (PGPB), ground magnesium limestone (GML) and ground basalt. Five-day-old rice seedlings were inoculated by Bacillus sp., Stenotrophomonas maltophila, Burkholderia thailandensis and Burkholderia seminalis and grown for 21 days in Hoagland solution (pH 4.0) at various Al concentrations (0, 50 and 100 μM). Toxicity symptoms in root and leaf were studied using scanning electron microscope. In the field, biofertilizer (PGPB), GML and basalt were applied (4 t·ha-1 each). Results showed that Al severely affected the growth of rice. At high concentrations, the root surface was ruptured, leading to cell collapse; however, no damages were observed in the PGPB inoculated seedlings. After 21 days of inoculation, solution pH increased to >6.0, while the control treatment remained same. Field study showed that the highest rice growth and yield were obtained in the bio-fertilizer and GML treatments. This study showed that Al toxicity was reduced by PGPB via production of organic acids that were able to chelate the Al and the production of polysaccharides that increased solution pH. The release of phytohormones further enhanced rice growth that resulted in yield increase.

  12. Isolation, characterization and beneficial effects of rice associated plant growth promoting bacteria from Zanzibar soils.

    PubMed

    Yasmin, Sumera; Rahman Bakar, M Abdul; Malik, Kausar A; Hafeez, Fauzia Y

    2004-01-01

    This study was undertaken to isolate and characterize plant growth promoting bacteria (PGPB) occurring in four soils of Zanzibar, Tanzania as well as to evaluate their potential use as biofertilizers for rice. A total of 12 PGPB strains were isolated from rice and studied for growth characteristics, carbon/nitrogen source utilization patterns using QTS-24 kits, phosphate solubilization, indole acetic acid (IAA) production, antibiotic resistance patterns and growth at different pH, temperature and salt concentrations. All the isolates were motile and gram negative except Z3-4. Acetylene reduction activity was detected in all isolates ranging from 5.9-76.4 nmole C2H2 reduced/h x mg protein while 9 isolates produced IAA ranged from 20-90.8 mg/l. Most of the isolates showed resistance against different environmental stresses like 10-40 degrees C temperature, 0.2-1 M salt concentration and 4-8.5 pH range. Only one isolate Z2-7 formed clear zones on Pikovskaia's medium showing its ability to solubilize phosphates. Z3-2 was used to develop fluorescent antibodies to check the cross reactivity of the isolates. Inoculation of these bacterial isolates resulted in higher plant biomass, root area, and total N and P contents on Tanzanian rice variety BKN PRAT3036B under controlled conditions. Bacillus sp. Z3-4 and Azospirillum sp. Z3-1 are effective strains and, after further testing under field conditions, can be used for inoculum production of rice in Tanzania. The plant growth promoting effects of these PGPRs suggest that these can be exploited to improve crop productivity of rice in Tanzania. Copyright 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  13. Contribution of Ethylene Biosynthesis for Resistance to Blast Fungus Infection in Young Rice Plants1[OA

    PubMed Central

    Iwai, Takayoshi; Miyasaka, Atsushi; Seo, Shigemi; Ohashi, Yuko

    2006-01-01

    The role of ethylene (ET) in resistance to infection with blast fungus (Magnaporthe grisea) in rice (Oryza sativa) is poorly understood. To study it, we quantified ET levels after inoculation, using young rice plants at the four-leaf stage of rice cv Nipponbare (wild type) and its isogenic plant (IL7), which contains the Pi-i resistance gene to blast fungus race 003. Small necrotic lesions by hypersensitive reaction (HR) were formed at 42 to 72 h postinoculation (hpi) in resistant IL7 leaves, and whitish expanding lesions at 96 hpi in susceptible wild-type leaves. Notable was the enhanced ET emission at 48 hpi accompanied by increased 1-aminocyclopropane-1-carboxylic acid (ACC) levels and highly elevated ACC oxidase (ACO) activity in IL7 leaves, whereas only an enhanced ACC increase at 96 hpi in wild-type leaves. Among six ACC synthase (ACS) and seven ACO genes found in the rice genome, OsACS2 was transiently expressed at 48 hpi in IL7 and at 96 hpi in wild type, and OsACO7 was expressed at 48 hpi in IL7. Treatment with an inhibitor for ACS, aminooxyacetic acid, suppressed enhanced ET emission at 48 hpi in IL7, resulting in expanding lesions instead of HR lesions. Exogenously supplied ACC compromised the aminooxyacetic acid-induced breakdown of resistance in IL7, and treatment with 1-methylcyclopropene and silver thiosulfate, inhibitors of ET action, did not suppress resistance. These findings suggest the importance of ET biosynthesis and, consequently, the coproduct, cyanide, for HR-accompanied resistance to blast fungus in young rice plants and the contribution of induced OsACS2 and OsACO7 gene expression to it. PMID:17012402

  14. Geochemical patterns and microbial contribution to iron plaque formation in the rice plant rhizosphere

    NASA Astrophysics Data System (ADS)

    Maisch, Markus; Murata, Chihiro; Unger, Julia; Kappler, Andreas; Schmidt, Caroline

    2015-04-01

    Rice is the major food source for more than half of the world population and 80 percent of the worldwide rice cultivation is performed on water logged paddy soils. The establishment of reducing conditions in the soil and across the soil-water interface not only stimulates the microbial production and release of the greenhouse gas methane. These settings also create optimal conditions for microbial iron(III) reduction and therefore saturate the system with reduced ferrous iron. Through the reduction and dissolution of ferric minerals that are characterized by their high surface activity, sorbed nutrients and contaminants (e.g. arsenic) will be mobilized and are thus available for uptake by plants. Rice plants have evolved a strategy to release oxygen from their roots in order to prevent iron toxification in highly ferrous environments. The release of oxygen to the reduced paddy soil causes ferric iron plaque formation on the rice roots and finally increases the sorption capacity for toxic metals. To this date the geochemical and microbiological processes that control the formation of iron plaque are not deciphered. It has been hypothesized that iron(II)-oxidizing bacteria play a potential role in the iron(III) mineral formation along the roots. However, not much is known about the actual processes, mineral products, and geochemical gradients that establish within the rhizosphere. In the present study we have developed a growth set-up that allows the co-cultivation of rice plants and iron(II)-oxidizing bacteria, as well as the visual observation and in situ measurement of geochemical parameters. Oxygen and dissolved iron(II) gradients have been measured using microelectrodes and show geochemical hot spots that offer optimal growth conditions for microaerophilic iron(II) oxidizers. First mineral identification attempts of iron plaque have been performed using Mössbauer spectroscopy and microscopy. The obtained results on mineraology and crystallinity have been

  15. A collection of cytochrome P450 monooxygenase genes involved in modification and detoxification of herbicide atrazine in rice (Oryza sativa) plants.

    PubMed

    Rong Tan, Li; Chen Lu, Yi; Jing Zhang, Jing; Luo, Fang; Yang, Hong

    2015-09-01

    Plant cytochrome P450 monooxygenases constitute one of the largest families of protein genes involved in plant growth, development and acclimation to biotic and abiotic stresses. However, whether these genes respond to organic toxic compounds and their biological functions for detoxifying toxic compounds such as herbicides in rice are poorly understood. The present study identified 201 genes encoding cytochrome P450s from an atrazine-exposed rice transcriptome through high-throughput sequencing. Of these, 69 cytochrome P450 genes were validated by microarray and some of them were confirmed by real time PCR. Activities of NADPH-cytochrome P450 reductase (CPR) and p-nitroanisole O-demethylase (PNOD) related to toxicity were determined and significantly induced by atrazine exposure. To dissect the mechanism underlying atrazine modification and detoxification by P450, metabolites (or derivatives) of atrazine in plants were analyzed by ultra performance liquid chromatography mass spectrometry (UPLC/MS). Major metabolites comprised desmethylatrazine (DMA), desethylatrazine (DEA), desisopropylatrazine (DIA), hydroxyatrazine (HA), hydroxyethylatrazine (HEA) and hydroxyisopropylatrazine (HIA). All of them were chemically modified by P450s. Furthermore, two specific inhibitors of piperonyl butoxide (PBO) and malathion (MAL) were used to assess the correlation between the P450s activity and rice responses including accumulation of atrazine in tissues, shoot and root growth and detoxification. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Vermicompost humic acids modulate the accumulation and metabolism of ROS in rice plants.

    PubMed

    García, Andrés Calderín; Santos, Leandro Azevedo; de Souza, Luiz Gilberto Ambrósio; Tavares, Orlando Carlos Huertas; Zonta, Everaldo; Gomes, Ernane Tarcisio Martins; García-Mina, José Maria; Berbara, Ricardo Luis Louro

    2016-03-15

    This work aims to determine the reactive oxygen species (ROS) accumulation, gene expression, anti-oxidant enzyme activity, and derived effects on membrane lipid peroxidation and certain stress markers (proline and malondialdehyde-MDA) in the roots of unstressed and PEG-stressed rice plants associated with vermicompost humic acid (VCHA) application. The results show that the application of VCHA to the roots of unstressed rice plants caused a slight but significant increase in root ROS accumulation and the gene expression and activity of the major anti-oxidant enzymes (superoxide dismutase and peroxidase). This action did not have negative effects on root development, and an increase in both root growth and root proliferation occurred. However, the root proline and MDA concentrations and the root permeability results indicate the development of a type of mild stress associated with VCHA application. When VCHA was applied to PEG-stressed plants, a clear alleviation of the inhibition in root development linked to PEG-mediated osmotic stress was observed. This was associated with a reduction in root ROS production and anti-oxidant enzymatic activity caused by osmotic stress. This alleviation of stress caused by VCHA was also reflected as a reduction in the PEG-mediated concentration of MDA in the root as well as root permeability. In summary, the beneficial action of VCHA on the root development of unstressed or PEG-stressed rice plants clearly involves the modulation of ROS accumulation in roots.

  17. [Oxidative stress in plants exposed to heavy metals].

    PubMed

    Rucińiska-Sobkowiak, Renata

    2010-01-01

    Oxidative stress has been involved in the toxicity of heavy metals in different plant species. Exposure to metal ions can intensify the production of reactive oxygen species (ROS) such as: superoxide radicals, hydroxyl radicals or hydrogen peroxide. These species can react with cellular components (lipids, proteins, nucleic acids) and cause lipid peroxidation, membrane damage and inactivation of enzymes thus affect many physiological processes as well as cell viability. Plants have evolved a complex array of mechanisms to maintain low ROS level and avoid the detrimental effects of excessively high ROS concentrations. This antioxidant network includes numerous soluble (ascorbate, glutathione) and membrane (tocopherol) compounds as well as enzymes involved in ROS scavenging (superoxide dismutase, catalase, ascorbate peroxidase). ROS must be efficiently detoxified to ameliorate the harmful effects of heavy metals in the cells. However they cannot be eliminated completely because plants use ROS as second messengers in signal transduction cascades in diverse physiological processes.

  18. Survival of Cd-exposed Arabidopsis thaliana: are these plants reproductively challenged?

    PubMed

    Keunen, Els; Truyens, Sascha; Bruckers, Liesbeth; Remans, Tony; Vangronsveld, Jaco; Cuypers, Ann

    2011-10-01

    Plants exposed to cadmium (Cd) show morphological and physiological disorders. To increase our knowledge regarding Cd-induced signalling, most often the effects of acute exposure are investigated. However, this does not allow in-depth analysis of morphological effects. Therefore, we chronically exposed Arabidopsis thaliana plants to environmentally realistic Cd concentrations (5 or 10 μM) and, using a described phenotypic framework methodology, we determined the impact of Cd on the plant's ability to complete its life cycle and produce germinative seeds. Visible Cd-induced morphological changes were observed within a short exposure period, with chlorotic and anthocyanous leaf colouring occurring dose-dependently. Although rosette growth was severely reduced in Cd-exposed plants, all plants were able to emerge inflorescences and produce siliques containing germinative seeds, thus confirming the non-lethality of the used Cd concentrations. Although the growth inhibition of Cd-exposed plants was dependent on the dose, both concentrations had similar effects on inflorescence height and silique counts. In conclusion, vegetative growth of plants chronically exposed to Cd is inhibited in a concentration-dependent manner. However, the effect on plant regeneration is clearly stress-determined but independent on the Cd concentration applied. In Arabidopsis thaliana, vegetative and reproductive growth are differentially influenced by Cd. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  19. 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.

  20. 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

  1. Dynamics of Seed-Borne Rice Endophytes on Early Plant Growth Stages

    PubMed Central

    Hardoim, Pablo R.; Hardoim, Cristiane C. P.; van Overbeek, Leonard S.; van Elsas, Jan Dirk

    2012-01-01

    Bacterial endophytes are ubiquitous to virtually all terrestrial plants. With the increasing appreciation of studies that unravel the mutualistic interactions between plant and microbes, we increasingly value the beneficial functions of endophytes that improve plant growth and development. However, still little is known on the source of established endophytes as well as on how plants select specific microbial communities to establish associations. Here, we used cultivation-dependent and -independent approaches to assess the endophytic bacterrial community of surface-sterilized rice seeds, encompassing two consecutive rice generations. We isolated members of nine bacterial genera. In particular, organisms affiliated with Stenotrophomonas maltophilia and Ochrobactrum spp. were isolated from both seed generations. PCR-based denaturing gradient gel electrophoresis (PCR-DGGE) of seed-extracted DNA revealed that approximately 45% of the bacterial community from the first seed generation was found in the second generation as well. In addition, we set up a greenhouse experiment to investigate abiotic and biotic factors influencing the endophytic bacterial community structure. PCR-DGGE profiles performed with DNA extracted from different plant parts showed that soil type is a major effector of the bacterial endophytes. Rice plants cultivated in neutral-pH soil favoured the growth of seed-borne Pseudomonas oryzihabitans and Rhizobium radiobacter, whereas Enterobacter-like and Dyella ginsengisoli were dominant in plants cultivated in low-pH soil. The seed-borne Stenotrophomonas maltophilia was the only conspicuous bacterial endophyte found in plants cultivated in both soils. Several members of the endophytic community originating from seeds were observed in the rhizosphere and surrounding soils. Their impact on the soil community is further discussed. PMID:22363438

  2. Rice proteomics: A move toward expanded proteome coverage to comparative and functional proteomics uncovers the mysteries of rice and plant biology.

    PubMed

    Agrawal, Ganesh Kumar; Rakwal, Randeep

    2011-05-01

    Growing rice is an important socio-economic activity. Rice proteomics has achieved a tremendous progress in establishing techniques to proteomes of almost all tissues, organs, and organelles during the past one decade (year 2000-2010). We have compiled these progresses time to time over this period. The present compilation discusses proteomics research in rice published between 1st April 2008 and 30th July 2010. Progress continues mainly towards protein cataloging deep into the proteome with high-confident protein assignment and some functional significance than ever before by (i) identifying previously unreported/low-abundance proteins, (ii) quantifying relative/absolute values of proteins, (iii) assigning protein responses to biotic/abiotic stresses, (iv) protein localization into organelles, (v) validating previous proteomes and eliminating false-positive proteins, and (vi) discovering potential biomarkers for tissues, organs, organelles, and for screening transgenic plants and food-safety evaluation. The notable achievements in global mapping of phosphorylation sites and identifying several novel secreted proteins into the extracellular space are worth appreciating. Our ever-increasing knowledge on the rice proteomics is beginning to impact the biology of not only rice, but also crops and plants. These major achievements will be discussed in this review keeping in mind newcomers, young, and established scientists in proteomics and plants. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. 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.

  4. [Effects of different nitrogen, phosphorous, and potassium fertilization modes on carbon- and nitrogen accumulation and allocation in rice plant].

    PubMed

    Feng, Lei; Tong, Cheng-li; Shi, Hui; Wu, Jin-shui; Chen, An-lei; Zhou, Ping

    2011-10-01

    Based on a 20-year field site-specific fertilization experiment in Taoyuan Experimental Station of Agriculture Ecosystems under Chinese Ecosystem Research Network (CERN), this paper studied the effects of different fertilization modes of N, P, and K on the accumulation and allocation of C and N in rice plant. The fertilization mode N-only showed the highest C and N contents (433 g kg(-1) and 18.9 g kg(-1), respectively) in rice grain, whereas the modes balanced fertilization of chemical N, P and K (NPK) and its combination with organic mature recycling (NPKC) showed the highest storage of C and N in rice plant. In treatments NPK and NPKC, the C storage in rice grain and in stem and leaf was 1960 kg hm(-2) and 2015 kg hm(-2), and 2002 kg hm(-2) and 2048 kg hm(-2), and the N storage in rice grain was 80.5 kg hm(-2) and 80.6 kg hm(-2), respectively. Treatment NPK had the highest N storage (59.3 kg hm(-2)) in stem and leaf. Balanced fertilization of chemical N, P, and K combined with organic manure recycling increased the accumulation of C and N in rice plant significantly. Comparing with applying N only, balanced fertilization of chemical N, P, and K was more favorable to the accumulation and allocation of C and N in rice plant during its growth period.

  5. Transgenic rice plants expressing trichothecene 3-O-acetyltransferase show resistance to the Fusarium phytotoxin deoxynivalenol.

    PubMed

    Ohsato, Shuichi; Ochiai-Fukuda, Tetsuko; Nishiuchi, Takumi; Takahashi-Ando, Naoko; Koizumi, Shinzo; Hamamoto, Hiroshi; Kudo, Toshiaki; Yamaguchi, Isamu; Kimura, Makoto

    2007-04-01

    Fusarium head blight (FHB) is a devastating disease of small grain cereal crops caused by the necrotrophic pathogen Fusarium graminearum and Fusarium culmorum. These fungi produce the trichothecene mycotoxin deoxynivalenol (DON) and its derivatives, which enhance the disease development during their interactions with host plants. For the self-protection, the trichothecene producer Fusarium species have Tri101 encoding trichothecene 3-O-acetyltransferase. Although transgenic expression of Tri101 significantly reduced inhibitory action of DON on tobacco plants, there are several conflicting observations regarding the phytotoxicity of 3-acetyldeoxynivalenol (3-ADON) to cereal plants; 3-ADON was reported to be highly phytotoxic to wheat at low concentrations. To examine whether cereal plants show sufficient resistance to 3-ADON, we generated transgenic rice plants with stable expression and inheritance of Tri101. While root growth of wild-type rice plants was severely inhibited by DON in the medium, this fungal toxin was not phytotoxic to the transgenic lines that showed trichothecene 3-O-acetylation activity. This is the first report demonstrating the DON acetylase activity and DON-resistant phenotype of cereal plants expressing the fungal gene.

  6. Delivery of roxarsone via chicken diet→chicken→chicken manure→soil→rice plant.

    PubMed

    Yao, Lixian; Huang, Lianxi; He, Zhaohuan; Zhou, Changmin; Lu, Weisheng; Bai, Cuihua

    2016-10-01

    Roxarsone (ROX), a widely used feed additive, occurs as itself and its metabolites in animal manure. Rice is prone to accumulate As than other staple food. Four diets with 0, 40, 80 and 120mgROXkg(-1) were fed in chickens, and four chicken manures (CMs) were collected to fertilize rice plants in a soil culture experiment. Linear regression analysis shows that the slopes of As species including 4-hydroxy-phenylarsonic acid, As(V), As(III), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) in CM versus dietary ROX were 0.033, 0.314, 0.033, 0.054 and 0.138, respectively. Both As(III) and DMA were determined in all rice grains, and As(III), As(V), MMA and DMA in rice hull, but detectable As forms in rice straws and soils increased with increasing ROX dose. Grain As(III) was unrelated to ROX dose but exceeded the Chinese rice As limit (0.15mgAs(III)kg(-1)). Dietary ROX enhanced straw As(III) mostly, with the slope of 0.020, followed by hull DMA (0.006) and grain DMA (0.002). The slopes of soil As(V) and As(III) were 0.003 and 0.001. This is the first report illustrating the quantitative delivery of ROX via food chain, which helps to evaluate health and environmental risks caused by ROX use in animal production. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Low Temperature Storage of Southern Rice Black-Streaked Dwarf Virus-Infected Rice Plants Cannot Sustain Virus Transmission by the Vector.

    PubMed

    Liu, Danfeng; Li, Pei; Han, Yongqiang; Lei, Wenbin; Hou, Maolin

    2016-02-01

    Southern rice black-streaked dwarf virus (SRBSDV) is a novel virus transmitted by white-backed planthopper Sogatella furcifera (Hováth) (Hemiptera: Delphacidae). Due to low virus transmission efficiency by the planthopper, researchers are frequently confronted with shortage of viruliferous vectors or infected rice plants, especially in winter and the following spring. To find new ways to maintain virus-infected materials, viral rice plants were stored at -80°C for 45 or 140 d and evaluated as virus sources in virus transmission by the vector. SRBSDV virions were not degraded during storage at -80°C as indicated by reverse transcription-polymerase chain reaction and reverse transcription real-time PCR detection. The planthopper nymphs fed on the infected thawed plants for 48 h survived at about 40% and showed positive detection of SRBSDV, but they lost the virus after feeding for another 20 d (the circulative transmission period) on noninfected plants. Transmission electron microscope images indicated broken capsid of virions in infected thawed leaves in contrast to integrity capsid of virions in infected fresh leaves. These results show that low temperature storage of SRBSDV-infected rice plants cannot sustain virus transmission by white-backed planthopper. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Recycling of solid waste rich in organic nitrogen from leather industry: mineral nutrition of rice plants.

    PubMed

    Nogueira, Francisco G E; Castro, Isabela A; Bastos, Ana R R; Souza, Guilherme A; de Carvalho, Janice G; Oliveira, Luiz C A

    2011-02-28

    The leather industry produces a large quantity of solid waste (wet blue leather), which contains a high amount of chromium. After its removal from wet blue leather, a solid collagenic material is recovered, containing high nitrogen levels, which can be used as a nitrogen source in agriculture. In order to take more advantage of the collagen, it was enriched with mineral P and K in order to produce NPK formulations. The objective was also to evaluate the efficiency of such formulations as a nutrient supply for rice plants in an Oxisoil, under greenhouse conditions. The application of PK enriched-collagen formulations resulted in N contents in the vegetative parts and grains of rice plants which were equivalent or superior to those obtained with urea and commercial NPK formulations. Copyright © 2010 Elsevier B.V. All rights reserved.

  9. Feasibility of estimating rice planting area of hilly region in southern China using remote sensing technique

    NASA Astrophysics Data System (ADS)

    Lai, Geying; Yang, Xingwei

    1998-08-01

    The objective of the study (Zhejiang province as study area) was to estimate rice planting area of hilly region in southern part of China by remote sensing technique with NOAA/AVHRR data. The research contents mainly concerned contrast tests on practical approaches, both digital elevation model (DEM) and digital slope model (DSM) derived from the digital relief map were used for the purpose of improving the classification accuracy of AVHRR imagery in large-area hilly region. The results indicated that the accuracy of maximum-likelihood (MLH) classification could satisfy the professional requirements of estimating rice planting area and fuzzy supervised classification based on unmixing AVHRR imagery has better classification accuracy and stability than MLH. In addition, the results through using both DEM and DSM as ancillary categorization data suggests DSM may improve the results of extracting paddy field signatures from AVHRR, particularly may improve the spatial accuracy, while DEM contribute nothing to improve the accuracy mentioned above.

  10. Rice Seed Priming with Picomolar Rutin Enhances Rhizospheric Bacillus subtilis CIM Colonization and Plant Growth.

    PubMed

    Singh, Akanksha; Gupta, Rupali; Pandey, Rakesh

    2016-01-01

    The effect of rutin, a bioflavonoid on the growth and biofilm formation of Bacillus subtilis strain CIM was investigated. In addition to swimming, swarming, and twitching potentials of B. subtilis CIM (BS), one picomolar (1 pM) of rutin was also observed to boost the biofilm forming ability of the bacterium. Bio-priming of rice seeds with BS and rutin not only augmented root and shoot lengths but also the photosynthetic pigments like chlorophyll and carotenoid. Similarly, high accumulation of phenolic and flavonoid contents was observed in the leaves. Fluorescent microscopic images revealed that BS plus rutin enhanced callose deposition in the leaves. It was also established that the least formation of reactive oxygen species in BS plus rutin treated rice plants was due to higher free radicals scavenging activity and total antioxidant potential. The results highlight chemo attractant nature of BS towards rutin, which by enhancing biofilm formation and root colonization indirectly strengthened the plants' defensive state.

  11. Analysis of Copper-Binding Proteins in Rice Radicles Exposed to Excess Copper and Hydrogen Peroxide Stress.

    PubMed

    Zhang, Hongxiao; Xia, Yan; Chen, Chen; Zhuang, Kai; Song, Yufeng; Shen, Zhenguo

    2016-01-01

    Copper (Cu) is an essential micronutrient for plants, but excess Cu can inactivate and disturb the protein function due to unavoidable binding to proteins at the cellular level. As a redox-active metal, Cu toxicity is mediated by the formation of reactive oxygen species (ROS). Cu-binding structural motifs may alleviate Cu-induced damage by decreasing free Cu(2+) activity in cytoplasm or scavenging ROS. The identification of Cu-binding proteins involved in the response of plants to Cu or ROS toxicity may increase our understanding the mechanisms of metal toxicity and tolerance in plants. This study investigated change of Cu-binding proteins in radicles of germinating rice seeds under excess Cu and oxidative stress using immobilized Cu(2+) affinity chromatography, two-dimensional electrophoresis, and mass spectra analysis. Quantitative image analysis revealed that 26 protein spots showed more than a 1.5-fold difference in abundances under Cu or H2O2 treatment compared to the control. The identified Cu-binding proteins were involved in anti-oxidative defense, stress response and detoxification, protein synthesis, protein modification, and metabolism regulation. The present results revealed that 17 out of 24 identified Cu-binding proteins have a similar response to low concentration Cu (20 μM Cu) and H2O2 stress, and 5 out of 24 were increased under low and high concentration Cu (100 μM Cu) but unaffected under H2O2 stress, which hint Cu ions can regulate Cu-binding proteins accumulation by H2O2 or no H2O2 pathway to cope with excess Cu in cell. The change pattern of these Cu-binding proteins and their function analysis warrant to further study the roles of Cu ions in these Cu-binding proteins of plant cells.

  12. Analysis of Copper-Binding Proteins in Rice Radicles Exposed to Excess Copper and Hydrogen Peroxide Stress

    PubMed Central

    Zhang, Hongxiao; Xia, Yan; Chen, Chen; Zhuang, Kai; Song, Yufeng; Shen, Zhenguo

    2016-01-01

    Copper (Cu) is an essential micronutrient for plants, but excess Cu can inactivate and disturb the protein function due to unavoidable binding to proteins at the cellular level. As a redox-active metal, Cu toxicity is mediated by the formation of reactive oxygen species (ROS). Cu-binding structural motifs may alleviate Cu-induced damage by decreasing free Cu2+ activity in cytoplasm or scavenging ROS. The identification of Cu-binding proteins involved in the response of plants to Cu or ROS toxicity may increase our understanding the mechanisms of metal toxicity and tolerance in plants. This study investigated change of Cu-binding proteins in radicles of germinating rice seeds under excess Cu and oxidative stress using immobilized Cu2+ affinity chromatography, two-dimensional electrophoresis, and mass spectra analysis. Quantitative image analysis revealed that 26 protein spots showed more than a 1.5-fold difference in abundances under Cu or H2O2 treatment compared to the control. The identified Cu-binding proteins were involved in anti-oxidative defense, stress response and detoxification, protein synthesis, protein modification, and metabolism regulation. The present results revealed that 17 out of 24 identified Cu-binding proteins have a similar response to low concentration Cu (20 μM Cu) and H2O2 stress, and 5 out of 24 were increased under low and high concentration Cu (100 μM Cu) but unaffected under H2O2 stress, which hint Cu ions can regulate Cu-binding proteins accumulation by H2O2 or no H2O2 pathway to cope with excess Cu in cell. The change pattern of these Cu-binding proteins and their function analysis warrant to further study the roles of Cu ions in these Cu-binding proteins of plant cells. PMID:27582750

  13. Trehalose accumulation in rice plants confers high tolerance levels to different abiotic stresses

    PubMed Central

    Garg, Ajay K.; Kim, Ju-Kon; Owens, Thomas G.; Ranwala, Anil P.; Choi, Yang Do; Kochian, Leon V.; Wu, Ray J.

    2002-01-01

    Trehalose is a nonreducing disaccharide of glucose that functions as a compatible solute in the stabilization of biological structures under abiotic stress in bacteria, fungi, and invertebrates. With the notable exception of the desiccation-tolerant “resurrection plants,” trehalose is not thought to accumulate to detectable levels in most plants. We report here the regulated overexpression of Escherichia coli trehalose biosynthetic genes (otsA and otsB) as a fusion gene for manipulating abiotic stress tolerance in rice. The fusion gene has the advantages of necessitating only a single transformation event and a higher net catalytic efficiency for trehalose formation. The expression of the transgene was under the control of either tissue-specific or stress-dependent promoters. Compared with nontransgenic rice, several independent transgenic lines exhibited sustained plant growth, less photo-oxidative damage, and more favorable mineral balance under salt, drought, and low-temperature stress conditions. Depending on growth conditions, the transgenic rice plants accumulate trehalose at levels 3–10 times that of the nontransgenic controls. The observation that peak trehalose levels remain well below 1 mg/g fresh weight indicates that the primary effect of trehalose is not as a compatible solute. Rather, increased trehalose accumulation correlates with higher soluble carbohydrate levels and an elevated capacity for photosynthesis under both stress and nonstress conditions, consistent with a suggested role in modulating sugar sensing and carbohydrate metabolism. These findings demonstrate the feasibility of engineering rice for increased tolerance of abiotic stress and enhanced productivity through tissue-specific or stress-dependent overproduction of trehalose. PMID:12456878

  14. Disruption of secondary wall cellulose biosynthesis alters cadmium translocation and tolerance in rice plants.

    PubMed

    Song, Xue-Qin; Liu, Li-Feng; Jiang, Yi-Jun; Zhang, Bao-Cai; Gao, Ya-Ping; Liu, Xiang-Ling; Lin, Qing-Shan; Ling, Hong-Qing; Zhou, Yi-Hua

    2013-05-01

    Tricheary elements (TEs), wrapped by secondary cell wall, play essential roles in water, mineral, and nutrient transduction. Cadmium (Cd) is a toxic heavy metal that is absorbed by roots and transported to shoot, leaves, and grains through vascular systems in plants. As rice is a major source of Cd intake, many efforts have been made to establish 'low-Cd rice'. However, no links have been found between cellulose biosynthesis and cadmium accumulation. We report here a rice brittle culm13 mutant, resulting from a novel missense mutation (E101K) [corrected] in the N-terminus of cellulose synthase subunit 9 (CESA9). Except for the abnormal mechanical strength, the mutant plants are morphologically indistinguishable from the wild-type plants. Transmission electron microscopy (TEM) and chemical analyses showed a slight reduction in secondary wall thickness and 22% decrease in cellulose content in bc13 plants. Moreover, this mutation unexpectedly confers the mutant plants Cd tolerance due to less Cd accumulation in leaves. Expression analysis of the genes required for Cd uptake and transport revealed complicated alterations after applying Cd to wild-type and bc13. The mutants were further found to have altered vascular structure. More importantly, Cd concentration in the xylem saps from the bc13 plants was significantly lower than that from the wild-type. Combining the analyses of CESA9 gene expression and Cd content retention in the cell-wall residues, we conclude that CESA9(E101K) [corrected] mutation alters cell-wall properties in the conducting tissues, which consequently affects Cd translocation efficiency that largely contributes to the low Cd accumulation in the mutant plants.

  15. Different bacterial populations associated with the roots and rhizosphere of rice incorporate plant-derived carbon.

    PubMed

    Hernández, Marcela; Dumont, Marc G; Yuan, Quan; Conrad, Ralf

    2015-03-01

    Microorganisms associated with the roots of plants have an important function in plant growth and in soil carbon sequestration. Rice cultivation is the second largest anthropogenic source of atmospheric CH4, which is a significant greenhouse gas. Up to 60% of fixed carbon formed by photosynthesis in plants is transported below ground, much of it as root exudates that are consumed by microorganisms. A stable isotope probing (SIP) approach was used to identify microorganisms using plant carbon in association with the roots and rhizosphere of rice plants. Rice plants grown in Italian paddy soil were labeled with (13)CO2 for 10 days. RNA was extracted from root material and rhizosphere soil and subjected to cesium gradient centrifugation followed by 16S rRNA amplicon pyrosequencing to identify microorganisms enriched with (13)C. Thirty operational taxonomic units (OTUs) were labeled and mostly corresponded to Proteobacteria (13 OTUs) and Verrucomicrobia (8 OTUs). These OTUs were affiliated with the Alphaproteobacteria, Betaproteobacteria, and Deltaproteobacteria classes of Proteobacteria and the "Spartobacteria" and Opitutae classes of Verrucomicrobia. In general, different bacterial groups were labeled in the root and rhizosphere, reflecting different physicochemical characteristics of these locations. The labeled OTUs in the root compartment corresponded to a greater proportion of the 16S rRNA sequences (∼20%) than did those in the rhizosphere (∼4%), indicating that a proportion of the active microbial community on the roots greater than that in the rhizosphere incorporated plant-derived carbon within the time frame of the experiment. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  16. Mechanisms of plant adaptation/memory in rice seedlings under arsenic and heat stress: expression of heat-shock protein gene HSP70

    PubMed Central

    Goswami, Alakananda; Banerjee, Rahul; Raha, Sanghamitra

    2010-01-01

    Background and aims Plants can withstand many abiotic stresses. Stress adaptation through retention of imprints of previous stress exposure has also been described in plants. We have characterized the imprint or memory of adaptive stress responses of rice seedlings to arsenic (As) and heat stress. Methodology Two-week-old rice seedlings (both with and without As) were given a 45 °C heat shock for 3 h. While under heat shock, the leafy portion of the seedlings was harvested at regular intervals. Subsequently, the seedlings were kept at room temperature for recovery and sampling continued over 3 h. Total RNA and protein were extracted from the leafy portion of the seedlings and complementary DNA (cDNA) was prepared from total RNA. The cDNA was used as a template for the polymerase chain reaction to identify the transcription level of HSP70. Protein extracted from the seedlings was western-blotted. HSP70 and actin (loading control) antibodies were used to recognize the proteins on the same blot. Principal results Our studies reveal that HSP70, a cellular chaperone gene, is over-expressed at the mRNA and protein levels when rice seedlings are exposed to As and heat. The effect is cumulative and increases with the duration of stress for 3 h. During 3 h recovery from heat stress at ambient temperatures for 3 h, the chaperone remains expressed at higher levels in plants pre-exposed to As. Conclusions Our findings demonstrate a retention of the imprint of previous stress exposure, perhaps through sustained activation of the signalling pathways upstream of over-expression of HSP70. Furthermore, stress-induced HSP70 expression was additive/cumulative for continued exposure to similar or different kinds of stress, indicating that a commonality of signal transduction networks is adopted when plants experience more than one stress. PMID:22476080

  17. Inspections of radiocesium concentration levels in rice from Fukushima Prefecture after the Fukushima Dai-ichi Nuclear Power Plant accident

    PubMed Central

    Nihei, Naoto; Tanoi, Keitaro; Nakanishi, Tomoko M.

    2015-01-01

    We summarize the inspections of radiocesium concentration levels in rice produced in Fukushima Prefecture, Japan, for 3 years from the nuclear accident in 2011. In 2011, three types of verifications, preliminary survey, main inspection, and emergency survey, revealed that rice with radiocesium concentration levels over 500 Bq/kg (the provisional regulation level until March 2012 in Japan) was identified in the areas north and west of the Fukushima nuclear power plant. The internal exposure of an average adult eating rice grown in the area north of the nuclear plant was estimated as 0.05 mSv/year. In 2012, Fukushima Prefecture authorities decided to investigate the radiocesium concentration levels in all rice using custom-made belt conveyor testers. Notably, rice with radiocesium concentration levels over 100 Bq/kg (the new standard since April 2012 in Japan) were detected in only 71 and 28 bags out of the total 10,338,000 in 2012 and 11,001,000 in 2013, respectively. We considered that there were almost no rice exceeding 100 Bq/kg produced in Fukushima Prefecture after 3 years from the nuclear accident, and the safety of Fukushima's rice were ensured because of the investigation of all rice. PMID:25731663

  18. Salt tolerant SUV3 overexpressing transgenic rice plants conserve physicochemical properties and microbial communities of rhizosphere.

    PubMed

    Sahoo, Ranjan K; Ansari, Mohammad W; Tuteja, Renu; Tuteja, Narendra

    2015-01-01

    Key concerns in the ecological evaluation of GM crops are undesirably spread, gene flow, other environmental impacts, and consequences on soil microorganism's biodiversity. Numerous reports have highlighted the effects of transgenic plants on the physiology of non-targeted rhizospheric microbes and the food chain via causing adverse effects. Therefore, there is an urgent need to develop transgenics with insignificant toxic on environmental health. In the present study, SUV3 overexpressing salt tolerant transgenic rice evaluated in New Delhi and Cuttack soil conditions for their effects on physicochemical and biological properties of rhizosphere. Its cultivation does not affect soil properties viz., pH, Eh, organic C, P, K, N, Ca, Mg, S, Na and Fe(2+). Additionally, SUV3 rice plants do not cause any change in the phenotype, species characteristics and antibiotic sensitivity of rhizospheric bacteria. The population and/or number of soil organisms such as bacteria, fungi and nematodes were unchanged in the soil. Also, the activity of bacterial enzymes viz., dehydrogenase, invertase, phenol oxidases, acid phosphatases, ureases and proteases was not significantly affected. Further, plant growth promotion (PGP) functions of bacteria such as siderophore, HCN, salicylic acid, IAA, GA, zeatin, ABA, NH3, phosphorus metabolism, ACC deaminase and iron tolerance were, considerably, not influenced. The present findings suggest ecologically pertinent of salt tolerant SUV3 rice to sustain the health and usual functions of the rhizospheric organisms. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. An NADPH-dependent genetic switch regulates plant infection by the rice blast fungus.

    PubMed

    Wilson, Richard A; Gibson, Robert P; Quispe, Cristian F; Littlechild, Jennifer A; Talbot, Nicholas J

    2010-12-14

    To cause rice blast disease, the fungus Magnaporthe oryzae breaches the tough outer cuticle of the rice leaf by using specialized infection structures called appressoria. These cells allow the fungus to invade the host plant and proliferate rapidly within leaf tissue. Here, we show that a unique NADPH-dependent genetic switch regulates plant infection in response to the changing nutritional and redox conditions encountered by the pathogen. The biosynthetic enzyme trehalose-6-phosphate synthase (Tps1) integrates control of glucose-6-phosphate metabolism and nitrogen source utilization by regulating the oxidative pentose phosphate pathway, the generation of NADPH, and the activity of nitrate reductase. We report that Tps1 directly binds to NADPH and, thereby, regulates a set of related transcriptional corepressors, comprising three proteins, Nmr1, Nmr2, and Nmr3, which can each bind NADP. Targeted deletion of any of the Nmr-encoding genes partially suppresses the nonpathogenic phenotype of a Δtps1 mutant. Tps1-dependent Nmr corepressors control the expression of a set of virulence-associated genes that are derepressed during appressorium-mediated plant infection. When considered together, these results suggest that initiation of rice blast disease by M. oryzae requires a regulatory mechanism involving an NADPH sensor protein, Tps1, a set of NADP-dependent transcriptional corepressors, and the nonconsuming interconversion of NADPH and NADP acting as signal transducer.

  20. Expression of peanut Iron Regulated Transporter 1 in tobacco and rice plants confers improved iron nutrition.

    PubMed

    Xiong, Hongchun; Guo, Xiaotong; Kobayashi, Takanori; Kakei, Yusuke; Nakanishi, Hiromi; Nozoye, Tomoko; Zhang, Lixia; Shen, Hongyun; Qiu, Wei; Nishizawa, Naoko K; Zuo, Yuanmei

    2014-07-01

    Iron (Fe) limitation is a widespread agricultural problem in calcareous soils and severely limits crop production. Iron Regulated Transporter 1 (IRT1) is a key component for Fe uptake from the soil in dicot plants. In this study, the peanut (Arachis hypogaea L.) AhIRT1 was introduced into tobacco and rice plants using an Fe-deficiency-inducible artificial promoter. Induced expression of AhIRT1 in tobacco plants resulted in accumulation of Fe in young leaves under Fe deficient conditions. Even under Fe-excess conditions, the Fe concentration was also markedly enhanced, suggesting that the Fe status did not affect the uptake and translocation of Fe by AhIRT1 in the transgenic plants. Most importantly, the transgenic tobacco plants showed improved tolerance to Fe limitation in culture in two types of calcareous soils. Additionally, the induced expression of AhIRT1 in rice plants also resulted in high tolerance to low Fe availability in calcareous soils.

  1. Study on allelopathic effects of Rice and Wheat Soil-Like Substrate on several plants

    NASA Astrophysics Data System (ADS)

    Li, Leyuan; Fu, Wenting; He, Wenting; Liu, Hong

    Rice and wheat are the traditional food of Chinese people, and therefore the main crop candidates for bio-regenerative life-support systems. Recycling rice and wheat straw is an important issue concerning the system. In order to decide if the mixed-substrate made of rice and wheat straw is suitable of plant cultivation, Rice and Wheat Soil-Like Substrate was tested in an aqueous extract germination experiment. The effects of different concentrations of aqueous extract on seed vigor, seedling growth and development situations and the physiological and biochemical characteristics of wheat, lettuce and pumpkin were studied, and the presence and degrees of allelopathic effects were analyzed. The test results showed that this type of SLS exerted different degrees of allelopathic effect on wheat and lettuce; this allelopathic effect was related to the concentration of SLS aqueous extract. The most significant phenomenon is that with the increase of aqueous extract concentration, the seed germination, root length and shoot fresh weight of wheat decreased; and every concentration of aqueous extract showed significant inhibition on the root length and root fresh weight of lettuce. However, this type of SLS showed little effect on the growth of pumpkin seedlings. Contents changes of chlorophyll and endogenous hormones in wheat and lettuce seedlings, and the chemical compositions of SLS were measured, and the mechanism of allelopathic effect was preliminarily analyzed.

  2. Molecular characterization and biological response to respiration inhibitors of Pyricularia isolates from ctenanthe and rice plants.

    PubMed

    Paplomatas, Epaminondas J; Pappas, Athanasios C; Syranidou, Elene

    2005-07-01

    The molecular profile and the biological response of isolates of Pyricularia oryzae Cavara obtained from ctenanthe to two strobilurins (azoxystrobin, kresoxim-methyl) and the phenylpyridinamine fungicide fluazinam were characterized, and compared with isolates from rice plants. Five different isozymes (alpha-esterase, lactate, malate, isocitrate and sorbitol dehydrogenases) and five random decamer primers for RAPD-PCR were used to generate molecular markers. Using unweighted pair-group with arithmetic average analysis, ctenanthe isolates were found to form a separate group distinct from that of the rice isolates for both sets of markers. Amplified polymorphic sequences of mitochondrial cytochrome b that were digested with Fnu4HI or StyI revealed no differences among Pyricularia isolates at amino acid positions 143 or 129 which confer resistance to strobilurins in several fungi. In absence of the alternative respiration inhibitor salicylhydroxamic acid (SHAM) the three fungicides showed inferior and variable efficacy, with a trend toward the rice isolate being less sensitive. The addition of SHAM enhanced the effectiveness of all fungicides against isolates regardless of their origin. Appressorium formation was the most vulnerable target of action of the respiration inhibitors and azoxystrobin the most effective. This is the first report of a comparison between the molecular profiles and sensitivities to respiration inhibitors for Pyricularia oryzae isolates from a non-gramineous host and from rice.

  3. Radish plant exposed to lunar material collected on the Apollo 12 mission

    NASA Technical Reports Server (NTRS)

    1970-01-01

    The leaves of this radish plant were rubbed with lunar material colleted on the Apollo 12 lunar landing mission in experiments conducted in the Manned Spacecraft Center's Lunar Receiving Laboratory. The plant was exposed to the material 30 days before this photograph was made. Evidently no ill effects resulted from contact with the lunar soil.

  4. Radish plant exposed to lunar material collected on the Apollo 12 mission

    NASA Technical Reports Server (NTRS)

    1970-01-01

    The leaves of this radish plant were rubbed with lunar material colleted on the Apollo 12 lunar landing mission in experiments conducted in the Manned Spacecraft Center's Lunar Receiving Laboratory. The plant was exposed to the material 30 days before this photograph was made. Evidently no ill effects resulted from contact with the lunar soil.

  5. 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.

  6. Plants regenerated from tissue culture contain stable epigenome changes in rice.

    PubMed

    Stroud, Hume; Ding, Bo; Simon, Stacey A; Feng, Suhua; Bellizzi, Maria; Pellegrini, Matteo; Wang, Guo-Liang; Meyers, Blake C; Jacobsen, Steven E

    2013-03-19

    Most transgenic crops are produced through tissue culture. The impact of utilizing such methods on the plant epigenome is poorly understood. Here we generated whole-genome, single-nucleotide resolution maps of DNA methylation in several regenerated rice lines. We found that all tested regenerated plants had significant losses of methylation compared to non-regenerated plants. Loss of methylation was largely stable across generations, and certain sites in the genome were particularly susceptible to loss of methylation. Loss of methylation at promoters was associated with deregulated expression of protein-coding genes. Analyses of callus and untransformed plants regenerated from callus indicated that loss of methylation is stochastically induced at the tissue culture step. These changes in methylation may explain a component of somaclonal variation, a phenomenon in which plants derived from tissue culture manifest phenotypic variability. DOI:http://dx.doi.org/10.7554/eLife.00354.001.

  7. Stable mercury isotope variation in rice plants (Oryza sativa L.) from the Wanshan mercury mining district, SW China.

    PubMed

    Yin, Runsheng; Feng, Xinbin; Meng, Bo

    2013-03-05

    To study the sources and transformations of Hg in the rice plant ( Oryza sativa L.), stable Hg isotope variations in different tissues (foliage, root, stem, and seed) of rice which were collected from the Wanshan mercury mine (WSMM, Guizhou province, SW China) were investigated by multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS). In comparison, Hg isotope compositions of paddy soil, lichen, and direct ambient air samples in WSMM were also analyzed. We observed that mass dependent fractionation (MDF) of Hg differed by up to ∼ 3.0‰ in δ(202)Hg values and that mass independent fractionation (MIF) of Hg isotopes affected the odd Hg isotopes to produce a ∼ 0.40‰ range in Δ(199)Hg (and Δ(201)Hg) values in tissues of rice plant. The 1:1 Δ(199)Hg/Δ(201)Hg ratio in tissues of rice supported the hypothesis that a fraction of Hg in tissues of rice plants has undergone a photoreduction process prior to being accumulated by rice plants. We suggest that the variation of MIF represents a mixing between soil Hg and atmospheric Hg in rice plants. The estimated fraction of atmospheric Hg (f) in tissues of rice followed the trend of f leaf > f stem > f seed > f root. Finally, we demonstrated a significant MDF of >1.0‰ in δ(202)Hg during the processes of absorption of atmospheric Hg by leaf tissues and of absorption of soil Hg by roots. Our study demonstrated that Hg isotopes may represent an important contribution both to the study of Hg transportation in plants and to the understanding of sources of Hg contamination to critical food crops.

  8. Quantitative descriptions of rice plant architecture and their application

    PubMed Central

    Li, Xumeng; Wang, Xiaohui; Peng, Yulin; Wei, Hailin; Zhu, Xinguang; Chang, Shuoqi; Li, Ming; Li, Tao; Huang, Huang

    2017-01-01

    Plant architecture is an important agronomic trait, and improving plant architecture has attracted the attention of scientists for decades, particularly studies to create desirable plant architecture for high grain yields through breeding and culture practices. However, many important structural phenotypic traits still lack quantitative description and modeling on structural-functional relativity. This study defined new architecture indices (AIs) derived from the digitalized plant architecture using the virtual blade method. The influences of varieties and crop management on these indices and the influences of these indices on biomass accumulation were analyzed using field experiment data at two crop growth stages: early and late panicle initiation. The results indicated that the vertical architecture indices (LAI, PH, 90%-DRI, MDI, 90%-LI) were significantly influenced by variety, water, nitrogen management and the interaction of water and nitrogen, and compact architecture indices (H-CI, Q-CI, 90%-LI, 50%-LI) were significantly influenced by nitrogen management and the interaction of variety and water. Furthermore, there were certain trends in the influence of variety, water, and nitrogen management on AIs. Biomass accumulation has a positive linear correlation with vertical architecture indices and has a quadratic correlation with compact architecture indices, respectively. Furthermore, the combination of vertical and compact architecture indices is the indicator for evaluating the effects of plant architecture on biomass accumulation. PMID:28545144

  9. 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.

  10. Cross-fertilization for enhancing tocotrienol biosynthesis in rice plants and QTL analysis of their F2 progenies.

    PubMed

    Sookwong, Phumon; Murata, Kazumasa; Nakagawa, Kiyotaka; Shibata, Akira; Kimura, Toshiyuki; Yamaguchi, Masayuki; Kojima, Yoichiro; Miyazawa, Teruo

    2009-06-10

    As rice bran tocotrienol (T3) has been known to have a wide range of physiological functions (e.g., antiangiogenesis), we aimed at developing a T3-rich rice variety for nutraceutical purposes. T3 content in more than 250 kinds of rice bran samples were investigated, and Milyang23 was found as the best variety rich in T3. The variety was therefore chosen for cross-fertilization with Koshihikari. Among obtained F(2) progenies, some of them became improved in T3 content (up to 2-fold of reference Koshihikari). QTL analysis of the F(2) progenies revealed five putative loci corresponding to T3 biosynthesis, in which the main loci were located near a marker RM3827 on chromosome 6. The results show that cross-breeding is effective in improving rice bran T3 and provides more genetic understanding on T3 biosynthesis in rice plants.

  11. Over-expression of PsGPD, a mushroom glyceraldehyde-3-phosphate dehydrogenase gene, enhances salt tolerance in rice plants.

    PubMed

    Cho, Jung-Il; Lim, Hye-Min; Siddiqui, Zamin Shaheed; Park, Sung-Han; Kim, A-Ram; Kwon, Taek-Ryoun; Lee, Seong-Kon; Park, Soo-Chul; Jeong, Mi-Jeong; Lee, Gang-Seob

    2014-08-01

    Transgenic potatoes expressing glyceraldehyde-3-phosphate dehydrogenase (GPD), isolated from the oyster mushroom, Pleurotus sajor-caju, had increased tolerance to salt stress (Jeong et al. Biochem Biophys Res Commun 278:192-196, 2000). To examine the physiological mechanisms enhancing salt tolerance in GPD-transgenic rice plants, the salt tolerance of five GPD transgenic rice lines (T1-T5) derived from Dongjin rice cultivar were evaluated in a fixed 150 mM saline environment in comparison to two known wild-type rice cultivars, Dongjin (salt sensitive) and Pokali (salt tolerant). Transgenic lines, T2, T3, and T5, had a substantial increase in biomass and relative water content compared to Dongjin. Stomatal conductance and osmotic potential were higher in the GPD transgenic lines and were similar to those in Pokali. The results are discussed based on the comparative physiological response of GPD transgenic lines with those of the salt-sensitive and salt-tolerant rice cultivars.

  12. In vitro plant regeneration through anther culture of some Iranian local rice (Oryza sativa L.) cultivars.

    PubMed

    Talebi, Reza; Rahemi, Mohammad Reza; Arefi, Habibolah; Nourozi, Mohammad; Bagheri, Nadali

    2007-06-15

    In this study, effect of different genotypes, different callus induction and regeneration media were investigated using seven Iranian local rice. Anthers were cultured on N6, Fj and L8 media containing the same hormonal combination 3 mg L(-1) NAA, 0.5 mg L(-1) Kn and 0.5 mg L(-1) 2, 4-D and incubated at 25 +/- 1 degree C in dark for callus induction. All varieties in L8 medium, five varieties in Fj medium and six varieties in N6 medium produced highest percentage of callus. Calli induced in different induction media were transferred to SK 11 and N 19 medium and incubated at 25 +/- 1 degree C in light for plantlet regeneration. Among seven varieties upon transfer to SK 11 medium, highest percentage (40%) of green plants were produced in Hassani and in N 19 medium the highest percentage (15.78) of green plants and albino plants (21.05) were produced in Anbarbo. The finding in the present investigation showed that the successfully emberyogenesis and green plant regeneration in rice anther culture dependent on medium culture components and are affected by the genetic mack-up of the plants.

  13. Isolation and characterization of plant growth promoting endophytic diazotrophic bacteria from Korean rice cultivars.

    PubMed

    Ji, Sang Hye; Gururani, Mayank Anand; Chun, Se-Chul

    2014-01-20

    We have isolated 576 endophytic bacteria from the leaves, stems, and roots of 10 rice cultivars and identified 12 of them as diazotrophic bacteria using a specific primer set of nif gene. Through 16S rDNA sequence analysis, nifH genes were confirmed in the two species of Penibacillus, three species of Microbacterium, three Bacillus species, and four species of Klebsiella. Rice seeds treated with these plant growth-promoting bacteria (PGPB) showed improved plant growth, increased height and dry weight and antagonistic effects against fungal pathogens. In addition, auxin and siderophore producing ability, and phosphate solubilizing activity were studied for the possible mechanisms of plant growth promotion. Among 12 isolates tested, 10 strains have shown higher auxin producing activity, 6 isolates were confirmed as strains with high siderophore producing activity while 4 isolates turned out to have high phosphate-solubilizing activity. These results strongly suggest that the endophytic diazotrophic bacteria characterized in this study could be successfully used to promote plant growth and inducing fungal resistance in plants.

  14. Effect of silicate on arsenic fractionation in soils and its accumulation in rice plants.

    PubMed

    Wu, Chuan; Zou, Qi; Xue, Sheng-Guo; Pan, Wei-Song; Yue, Xu; Hartley, William; Huang, Liu; Mo, Jing-Yu

    2016-12-01

    Four rice genotypes, two hybrid and two indica, were selected to investigate the effects of silicate (Si) application on arsenic (As) accumulation and speciation in rice and As fractionation in soil. There were significant differences in root, straw and grain biomass among genotypes (p < 0.05), and Si application significantly increased root (p < 0.05) and grain biomass (p < 0.001). Silicate addition reduced the proportion of As associated with well-crystallized hydrous oxides of Fe and Al and residual phases, whilst increasing the proportions of specifically-sorbed As and As associated with amorphous and poorly-crystalline Fe and Al hydrous oxides. Furthermore, the results indicated that the fraction proportions of non-specifically sorbed, specifically-sorbed, and associated with amorphous and poorly-crystalline hydrous oxides of Fe and Al in rhizosphere soils, were greater than non-rhizosphere soils. Silicate application had a significant effect decreasing total As concentrations in root (p < 0.005), straw (p < 0.05) and husk (p < 0.001) of rice plants. The effect of Si on reducing As accumulation in rice leaves was revealed by SXRF. Indica genotypes transported and accumulated less As than hybrid genotypes. Both percentage and concentration of iAs were lower in indica genotype XFY-9 than in hybrid genotype XWX-12. Silicate reduced iAs and DMA by 21% and 58% in grain (polished) respectively. DMA may have a greater translocation capacity from straw to grain (polished) than inorganic As. The study provides the potential for understanding As uptake mechanisms in rice and mitigating the health risks posed by As contamination in paddy fields.

  15. Strong shift in the diazotrophic endophytic bacterial community inhabiting rice (Oryza sativa) plants after flooding.

    PubMed

    Ferrando, Lucía; Fernández Scavino, Ana

    2015-09-01

    Flooding impacts soil microbial communities, but its effect on endophytic communities has rarely been explored. This work addresses the effect of flooding on the abundance and diversity of endophytic diazotrophic communities on rice plants established in a greenhouse experiment. The nifH gene was significantly more abundant in roots after flooding, whereas the nifH gene copy numbers in leaves were unaffected and remained low. The PCA (principal component analysis) of T-RFLP (terminal restriction fragment length polymorphism) profiles indicated that root communities of replicate plots were more similar and diverse after flooding than before flooding. The nifH libraries obtained by cloning and 454 pyrosequencing consistently showed a remarkable shift in the diazotrophic community composition after flooding. Gammaproteobacteria (66-98%), mainly of the genus Stenotrophomonas, prevailed in roots before flooding, whereas Betaproteobacteria was the dominant class (26-34%) after flooding. A wide variety of aerotolerant and anaerobic diazotrophic bacteria (e.g. Dechloromonas, Rhodopseudomonas, Desulfovibrio, Geobacter, Chlorobium, Spirochaeta, Selenomonas and Dehalobacter) with diverse metabolic traits were retrieved from flooded rice roots. These findings suggest that endophytic communities could be significantly impacted by changes in plant-soil conditions derived from flooding during rice cropping. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  16. The rice Mybleu transcription factor increases tolerance to oxygen deprivation in Arabidopsis plants.

    PubMed

    Mattana, Monica; Vannini, Candida; Espen, Luca; Bracale, Marcella; Genga, Annamaria; Marsoni, Milena; Iriti, Marcello; Bonazza, Veronica; Romagnoli, Francesco; Baldoni, Elena; Coraggio, Immacolata; Locatelli, Franca

    2007-09-01

    Mybleu is a natural incomplete transcription factor of rice (Oryza sativa), consisting of a partial Myb repeat followed by a short leucine zipper. We previously showed its localization to the apical region of rice roots and coleoptiles. Specifically, in coleoptiles, Mybleu is expressed under both aerobic and anaerobic conditions, whereas in roots, it is expressed only under aerobic conditions. Mybleu is able to dimerize with canonical leucine zippers and to activate transcription selectively. To investigate Mybleu function in vivo, we transformed Arabidopsis thaliana and evaluated several morphological, physiological and biochemical parameters. In agreement with a hypothesized role of Mybleu in cell elongation in the differentiation zone, we found that the constitutive expression of this transcription factor in Arabidopsis induced elongation in the primary roots and in the internodal region of the floral stem; we also observed a modification of the root apex morphology in transformed lines. Based on the high expression of Mybleu in anaerobic rice coleoptiles, we studied the role of this transcription factor in transgenic plants grown under low-oxygen conditions. We found that overexpression of this transcription factor increased tolerance to oxygen deficit. In transgenic plants, this effect may depend both on the maintenance of a higher metabolism during stress and on the higher expression levels of certain genes involved in the anaerobic response.

  17. [Dynamics of DDMS and DDMU in soils under rice and ryegrass planting].

    PubMed

    An, Qiong; Dong, Yuan-hua; Wei, Feng; Wang, Hui; Liang, Pan-xia

    2007-12-01

    Dynamics of DDMS and DDMU in soils with DDT application under rice and ryegrass planting by pot experiment in greenhouse was conducted. Results show that DDE/DDD is slightly increased, and only about 20 ng x g(-1) DDMU or DDMS could be found in ryegrass soil at the end of the experiment. However, the DDD, DDMS and DDMU are formed very rapidly in rice soil. By the 84th day of the experiment of rice planting, DDT residue is 70-80 ng x g(-1), about 2% of the concentration added at the first of the experiment, meanwhile, concentrations of DDD, DDMS and DDMU are increased to the highest level. Concentration of DDMS and DDMU is detected at 28 and 115 ng x g(-1) respectively. On the other hand, above phenomena are not observed in the aged DDT of soils, which implies that submerging could increase degradation of DDT added newly to DDD and DDMS/DDMU, but not for the aged DDT of soils.

  18. Composting rice straw with sewage sludge and compost effects on the soil-plant system.

    PubMed

    Roca-Pérez, L; Martínez, C; Marcilla, P; Boluda, R

    2009-05-01

    Composting organic residue is an interesting alternative to recycling waste as the compost obtained may be used as organic fertilizer. This study aims to assess the composting process of rice straw and sewage sludge on a pilot-scale, to evaluate both the quality of the composts obtained and the effects of applying such compost on soil properties and plant development in pot experiments. Two piles, with shredded and non-shredded rice straw, were composted as static piles with passive aeration. Throughout the composting process, a number of parameters were determined, e.g. colour, temperature, moisture, pH, electrical conductivity, organic matter, C/N ratio, humification index, cation exchange capacity, chemical oxygen demand, and germination index. Moreover, sandy and clayey soils were amended with different doses of mature compost and strewed with barley in pot experiments. The results show that compost made from shredded rice straw reached the temperatures required to maximise product sanitisation, and that the parameters indicating compost maturity were all positive; however, the humification index and NH(4) content were more selective. Therefore, using compost-amended soils at a dose of 34 Mg ha(-1) for sandy soil, and of 11 Mg ha(-1) for clayey soil improves soil properties and the growth of Hordeum vulgare plants. Under there conditions, the only limiting factor of agronomic compost utilisation was the increased soil salinity.

  19. 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

  20. Accumulation, translocation and conversion of six arsenic species in rice plants grown near a mine impacted city.

    PubMed

    Ma, Li; Wang, Lin; Jia, Yuyu; Yang, Zhaoguang

    2017-09-01

    Paddy rice (Oryza sativa L.) as the staple food in China was found to be efficient in accumulating arsenic (As) due to cultivated in flooded paddy soil. Uptake and translocation of As in rice plant depended on the As species. In this work, rice plant samples including roots, straws and grains as well as rhizosphere soils were collected from paddy fields near Changsha, a mine impacted city in Southern China. The total As concentrations in the collected samples were observed in the descending order as root > soil > straw > grain. The predominant As species detected in rice plants were inorganic forms: arsenite [As(III)] and arsenate [As(V)]. Except monomethylarsonate (MMA) and dimethylarsinate (DMA), other two organoarsenicals, arsenobetaine (AsB) and arsenocholine (AsC), were also detected in rice plants. DMA and AsB were mainly formed in rice roots with the assistance of microorganisms. MMA and AsC detected in straws might be derived from methylation and oxidation of As(III). The results of multiple linear regressions indicated that the straw As species were remarkable predictors of the corresponding grain As species. Demethylation or degradation of MMA, DMA and AsC were predicted when translocated from straw to grain. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Economic Analysis of Planting Forests on Rice Lands in Texas: Sequestering Carbon and Avoiding Methane Production

    NASA Astrophysics Data System (ADS)

    Kronrad, G. D.; Huang, C.

    2005-12-01

    Global climate change is predicted due to increases in greenhouse gasses (i.e. CO2, CH4, CFCs, N2O, O3) in the atmosphere caused by human activities. The atmospheric concentration of methane (CH4), which absorbs and retains heat 21 times more effectively than CO2, has increased. Anaerobic bacterial activity in rice paddies constitutes one of major emission sources of CH4. The rice fields of Texas, for example, accounted for an annual CH4 emission of between 1.1 and 1.6 million tons of CO2 equivalent between 1990 and 2000. Converting marginal rice fields to forests plantations will remove CO2 from the atmosphere, sequester carbon in the forests and prevent the production of CH4. Therefore, carbon credits can be claimed for the carbon sequestered and the avoidance of CH4 production. Analyses were conducted to calculate the amount of carbon sequestered and methane avoided, and the profitability, measured in net present worth (NPW), of managing loblolly pine plantation for 1) timber production only, 2) the dual products of timber products and carbon credits in forests planted on marginal agricultural and unused pastureland and 3) the dual products of timber and carbon storage in forests planted on marginal rice lands. Calculations were performed using three discount rates, three site qualities and five prices for carbon credits. The results indicate that on average quality land, using a discount rate of 8 percent, forests planted on marginal agricultural and unused pastureland earn a NPW of 346 per acre from timber production only; a NPW of 438 per acre from timber and carbon credits (54.4 tons of carbon sequestered), assuming carbon is worth 10 per ton, during one rotation (32 years). The profitability of forest management increases due to the inclusion of carbon credits. The profitability of planting forests on marginal rice fields is even higher, earning a NPW of 566 per acre from timber and carbon credits (54.4 tons of C sequestered and 33.3 tons of C emission

  2. Uptake and translocation of imidacloprid, thiamethoxam and difenoconazole in rice plants.

    PubMed

    Ge, Jing; Cui, Kai; Yan, Huangqian; Li, Yong; Chai, Yangyang; Liu, Xianjin; Cheng, Jiangfeng; Yu, Xiangyang

    2017-07-01

    Uptake and translocation of imidacloprid (IMI), thiamethoxam (THX) and difenoconazole (DFZ) in rice plants (Oryza sativa L.) were investigated with a soil-treated experiment at two application rates: field rate (FR) and 10*FR under laboratory conditions. The dissipation of the three compounds in soil followed the first-order kinetics and DFZ showed greater half-lives than IMI and THX. Detection of the three compounds in rice tissues indicated that rice plants could take up and accumulate these pesticides. The concentrations of IMI and THX detected in leaves (IMI, 10.0 and 410 mg/kg dw; THX, 23.0 and 265 mg/kg dw) were much greater than those in roots (IMI, 1.37 and 69.3 mg/kg dw; THX, 3.19 and 30.6 mg/kg dw), which differed from DFZ. The DFZ concentrations in roots (15.6 and 79.1 mg/kg dw) were much greater than those in leaves (0.23 and 3.4 mg/kg dw). The bioconcentration factor (BCF), representing the capability of rice to accumulate contaminants from soil into plant tissues, ranged from 1.9 to 224.3 for IMI, from 2.0 to 72.3 for THX, and from 0.4 to 3.2 for DFZ at different treated concentrations. Much higher BCFs were found for IMI and THX at 10*FR treatment than those at FR treatment, however, the BCFs of DFZ at both treatments were similar. The translocation factors (TFs), evaluating the capability of rice to translocate contaminants from the roots to the aboveground parts, ranged from 0.02 to 0.2 for stems and from 0.02 to 9.0 for leaves. The tested compounds were poorly translocated from roots to stems, with a TF below 1. However, IMI and THX were well translocated from roots to leaves. Clothianidin (CLO), the main metabolite of THX, was detected at the concentrations from 0.02 to 0.5 mg kg(-1) in soil and from 0.07 to 7.0 mg kg(-1) in plants. Concentrations of CLO in leaves were almost 14 times greater than those in roots at 10*FR treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. 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.

  4. Overproduction of C4 photosynthetic enzymes in transgenic rice plants: an approach to introduce the C4-like photosynthetic pathway into rice.

    PubMed

    Taniguchi, Yojiro; Ohkawa, Hiroshi; Masumoto, Chisato; Fukuda, Takuya; Tamai, Tesshu; Lee, Kwanghong; Sudoh, Sizue; Tsuchida, Hiroko; Sasaki, Haruto; Fukayama, Hiroshi; Miyao, Mitsue

    2008-01-01

    Four enzymes, namely, the maize C(4)-specific phosphoenolpyruvate carboxylase (PEPC), the maize C(4)-specific pyruvate, orthophosphate dikinase (PPDK), the sorghum NADP-malate dehydrogenase (MDH), and the rice C(3)-specific NADP-malic enzyme (ME), were overproduced in the mesophyll cells of rice plants independently or in combination. Overproduction individually of PPDK, MDH or ME did not affect the rate of photosynthetic CO(2) assimilation, while in the case of PEPC it was slightly reduced. The reduction in CO(2) assimilation in PEPC overproduction lines remained unaffected by overproduction of PPDK, ME or a combination of both, however it was significantly restored by the combined overproduction of PPDK, ME, and MDH to reach levels comparable to or slightly higher than that of non-transgenic rice. The extent of the restoration of CO(2) assimilation, however, was more marked at higher CO(2) concentrations, an indication that overproduction of the four enzymes in combination did not act to concentrate CO(2) inside the chloroplast. Transgenic rice plants overproducing the four enzymes showed slight stunting. Comparison of transformants overproducing different combinations of enzymes indicated that overproduction of PEPC together with ME was responsible for stunting, and that overproduction of MDH had some mitigating effects. Possible mechanisms underlying these phenotypic effects, as well as possibilities and limitations of introducing the C(4)-like photosynthetic pathway into C(3) plants, are discussed.

  5. [Effects of ozone stress on photosynthesis and dry matter production of rice II -you 084 under different Planting densities].

    PubMed

    Peng, Bin; Lai, Shang-kun; Li, Pan-lin; Wang, Yun-xia; Zhu, Jian-guo; Yang, Lian-xin; Wang, Yu-long

    2015-01-01

    In order to investigate the effects of ozone stress on photosynthesis, dry matter production, non-structural carbohydrate and yield formation of rice, a free air ozone concentration enrichment (FACE) experiment was conducted. A super hybrid rice cultivar II-you 084 with 3 spacing levels, low plant density (LD, 16 hills per m2), medium (MD, 24 hills per m2) and high plant density (HD, 32 hills per m2), was grown in the field at current and elevated ozone concentrations (current × 1.5). The results were as follows: Elevated ozone significantly reduced leaf SPAD value of UI-you 084 by 6%, 11% and 13%, at 63, 77, and 86 days after transplanting, respectively. The declines in leaf net photosynthetic rate, stomatal conductance and transpiration rate at filling stage increased significantly on ozone stress over time. Ozone stress decreased dry matter production of rice by 46% from heading stage to plant maturity, thus reduced biomass yield by 25%. Elevated ozone decreased the concentration and accumulation of soluble carbohydrate and starch in stem of II-you 084 at jointing, heading and plant maturity, but significantly increased the dry matter transportation rate. No significant interaction was observed between ozone and planting density for photosynthesis, dry matter production and non-structural carbohydrate of rice. The above results indicated that elevated ozone reduced photosynthesis and growth of rice II-you 084 at late growth stage, which had no relationship with planting density.

  6. Increase of Fungal Pathogenicity and Role of Plant Glutamine in Nitrogen-Induced Susceptibility (NIS) To Rice Blast

    PubMed Central

    Huang, Huichuan; Nguyen Thi Thu, Thuy; He, Xiahong; Gravot, Antoine; Bernillon, Stéphane; Ballini, Elsa; Morel, Jean-Benoit

    2017-01-01

    Highlight  Modifications in glutamine synthetase OsGS1-2 expression and fungal pathogenicity underlie nitrogen-induced susceptibility to rice blast. Understanding why nitrogen fertilization increase the impact of many plant diseases is of major importance. The interaction between Magnaporthe oryzae and rice was used as a model for analyzing the molecular mechanisms underlying Nitrogen-Induced Susceptibility (NIS). We show that our experimental system in which nitrogen supply strongly affects rice blast susceptibility only slightly affects plant growth. In order to get insights into the mechanisms of NIS, we conducted a dual RNA-seq experiment on rice infected tissues under two nitrogen fertilization regimes. On the one hand, we show that enhanced susceptibility was visible despite an over-induction of defense gene expression by infection under high nitrogen regime. On the other hand, the fungus expressed to high levels effectors and pathogenicity-related genes in plants under high nitrogen regime. We propose that in plants supplied with elevated nitrogen fertilization, the observed enhanced induction of plant defense is over-passed by an increase in the expression of the fungal pathogenicity program, thus leading to enhanced susceptibility. Moreover, some rice genes implicated in nitrogen recycling were highly induced during NIS. We further demonstrate that the OsGS1-2 glutamine synthetase gene enhances plant resistance to M. oryzae and abolishes NIS and pinpoint glutamine as a potential key nutrient during NIS. PMID:28293247

  7. Increase of Fungal Pathogenicity and Role of Plant Glutamine in Nitrogen-Induced Susceptibility (NIS) To Rice Blast.

    PubMed

    Huang, Huichuan; Nguyen Thi Thu, Thuy; He, Xiahong; Gravot, Antoine; Bernillon, Stéphane; Ballini, Elsa; Morel, Jean-Benoit

    2017-01-01

    Highlight  Modifications in glutamine synthetase OsGS1-2 expression and fungal pathogenicity underlie nitrogen-induced susceptibility to rice blast. Understanding why nitrogen fertilization increase the impact of many plant diseases is of major importance. The interaction between Magnaporthe oryzae and rice was used as a model for analyzing the molecular mechanisms underlying Nitrogen-Induced Susceptibility (NIS). We show that our experimental system in which nitrogen supply strongly affects rice blast susceptibility only slightly affects plant growth. In order to get insights into the mechanisms of NIS, we conducted a dual RNA-seq experiment on rice infected tissues under two nitrogen fertilization regimes. On the one hand, we show that enhanced susceptibility was visible despite an over-induction of defense gene expression by infection under high nitrogen regime. On the other hand, the fungus expressed to high levels effectors and pathogenicity-related genes in plants under high nitrogen regime. We propose that in plants supplied with elevated nitrogen fertilization, the observed enhanced induction of plant defense is over-passed by an increase in the expression of the fungal pathogenicity program, thus leading to enhanced susceptibility. Moreover, some rice genes implicated in nitrogen recycling were highly induced during NIS. We further demonstrate that the OsGS1-2 glutamine synthetase gene enhances plant resistance to M. oryzae and abolishes NIS and pinpoint glutamine as a potential key nutrient during NIS.

  8. Quantitative Trait Locus Mapping and Candidate Gene Analysis for Plant Architecture Traits Using Whole Genome Re-Sequencing in Rice

    PubMed Central

    Lim, Jung-Hyun; Yang, Hyun-Jung; Jung, Ki-Hong; Yoo, Soo-Cheul; Paek, Nam-Chon

    2014-01-01

    Plant breeders have focused on improving plant architecture as an effective means to increase crop yield. Here, we identify the main-effect quantitative trait loci (QTLs) for plant shape-related traits in rice (Oryza sativa) and find candidate genes by applying whole genome re-sequencing of two parental cultivars using next-generation sequencing. To identify QTLs influencing plant shape, we analyzed six traits: plant height, tiller number, panicle diameter, panicle length, flag leaf length, and flag leaf width. We performed QTL analysis with 178 F7 recombinant in-bred lines (RILs) from a cross of japonica rice line ‘SNUSG1’ and indica rice line ‘Milyang23’. Using 131 molecular markers, including 28 insertion/deletion markers, we identified 11 main- and 16 minor-effect QTLs for the six traits with a threshold LOD value > 2.8. Our sequence analysis identified fifty-four candidate genes for the main-effect QTLs. By further comparison of coding sequences and meta-expression profiles between japonica and indica rice varieties, we finally chose 15 strong candidate genes for the 11 main-effect QTLs. Our study shows that the whole-genome sequence data substantially enhanced the efficiency of polymorphic marker development for QTL fine-mapping and the identification of possible candidate genes. This yields useful genetic resources for breeding high-yielding rice cultivars with improved plant architecture. PMID:24599000

  9. Rice Seed Priming with Picomolar Rutin Enhances Rhizospheric Bacillus subtilis CIM Colonization and Plant Growth

    PubMed Central

    Singh, Akanksha; Gupta, Rupali; Pandey, Rakesh

    2016-01-01

    The effect of rutin, a bioflavonoid on the growth and biofilm formation of Bacillus subtilis strain CIM was investigated. In addition to swimming, swarming, and twitching potentials of B. subtilis CIM (BS), one picomolar (1 pM) of rutin was also observed to boost the biofilm forming ability of the bacterium. Bio-priming of rice seeds with BS and rutin not only augmented root and shoot lengths but also the photosynthetic pigments like chlorophyll and carotenoid. Similarly, high accumulation of phenolic and flavonoid contents was observed in the leaves. Fluorescent microscopic images revealed that BS plus rutin enhanced callose deposition in the leaves. It was also established that the least formation of reactive oxygen species in BS plus rutin treated rice plants was due to higher free radicals scavenging activity and total antioxidant potential. The results highlight chemo attractant nature of BS towards rutin, which by enhancing biofilm formation and root colonization indirectly strengthened the plants’ defensive state. PMID:26742102

  10. Gene expression and plant hormone levels in two contrasting rice genotypes responding to brown planthopper infestation.

    PubMed

    Li, Changyan; Luo, Chao; Zhou, Zaihui; Wang, Rui; Ling, Fei; Xiao, Langtao; Lin, Yongjun; Chen, Hao

    2017-02-28

    The brown planthopper (BPH; Nilaparvata lugens Stål) is a destructive piercing-sucking insect pest of rice. The plant hormones salicylic acid (SA) and jasmonic acid (JA) play important roles in plant-pest interactions. Many isolated rice genes that modulate BPH resistance are involved in the metabolism or signaling pathways of SA, JA and ethylene. 'Rathu Heenati' (RH) is a rice cultivar with a high-level, broad-spectrum resistance to all BPH biotypes. Here, RH was used as the research material, while a BPH-susceptible rice cultivar 'Taichung Native 1' (TN1) was the control. A cDNA microarray analysis illuminated the resistance response at the genome level of RH under BPH infestation. The levels of SA and JA in RH and TN1 seedlings after BPH infestation were also determined. The expression pattern clustering indicated that 1467 differential probe sets may be associated with constitutive resistance and 67 with the BPH infestation-responsive resistance of RH. A Venn diagram analysis revealed 192 RH-specific and BPH-inducible probe sets. Finally, 23 BPH resistance-related gene candidates were selected based on the expression pattern clustering and Venn diagram analysis. In RH, the SA content significantly increased and the JA content significantly decreased after BPH infestation, with the former occurring prior to the latter. In RH, the differential genes in the SA pathway were synthesis-related and were up-regulated after BPH infestation. The differential genes in the JA pathway were also up-regulated. They were jasmonate ZIM-domain transcription factors, which are important negative regulators of the JA pathway. Comparatively, genes involved in the ET pathway were less affected by a BPH infestation in RH. DNA sequence analysis revealed that most BPH infestation-inducible genes may be regulated by the genetic background in a trans-acting manner, instead of by their promoters. We profiled the analysis of the global gene expression in RH and TN1 under BPH infestation

  11. Metaproteomic identification of diazotrophic methanotrophs and their localization in root tissues of field-grown rice plants.

    PubMed

    Bao, Zhihua; Okubo, Takashi; Kubota, Kengo; Kasahara, Yasuhiro; Tsurumaru, Hirohito; Anda, Mizue; Ikeda, Seishi; Minamisawa, Kiwamu

    2014-08-01

    In a previous study by our group, CH4 oxidation and N2 fixation were simultaneously activated in the roots of wild-type rice plants in a paddy field with no N input; both processes are likely controlled by a rice gene for microbial symbiosis. The present study examined which microorganisms in rice roots were responsible for CH4 oxidation and N2 fixation under the field conditions. Metaproteomic analysis of root-associated bacteria from field-grown rice (Oryza sativa Nipponbare) revealed that nitrogenase complex-containing nitrogenase reductase (NifH) and the alpha subunit (NifD) and beta subunit (NifK) of dinitrogenase were mainly derived from type II methanotrophic bacteria of the family Methylocystaceae, including Methylosinus spp. Minor nitrogenase proteins such as Methylocella, Bradyrhizobium, Rhodopseudomonas, and Anaeromyxobacter were also detected. Methane monooxygenase proteins (PmoCBA and MmoXYZCBG) were detected in the same bacterial group of the Methylocystaceae. Because these results indicated that Methylocystaceae members mediate both CH4 oxidation and N2 fixation, we examined their localization in rice tissues by using catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH). The methanotrophs were localized around the epidermal cells and vascular cylinder in the root tissues of the field-grown rice plants. Our metaproteomics and CARD-FISH results suggest that CH4 oxidation and N2 fixation are performed mainly by type II methanotrophs of the Methylocystaceae, including Methylosinus spp., inhabiting the vascular bundles and epidermal cells of rice roots.

  12. Chlorophyll fluorescence from creosote-exposed plants in mesocosms: Validation of a bioindicator

    SciTech Connect

    Marwood, C.A.; Harris, M.L.; Day, K.E.; Greenberg, B.M.; Solomon, K.R.

    1995-12-31

    The chlorophyll fluorescence assay is a rapid, sensitive measure of photosynthetic competence in higher plants and algae that can be used to detect the impact of toxicants at many sites in the plant cell. Chlorophyll fluorescence was examined in plants exposed to PAHs as part of a study to validate chlorophyll fluorescence as a bioindicator by correlating effects on fluorescence with population-level effects in outdoor mesocosms. The wood preservative creosote was used as a mixed PAH source. Two species of aquatic plants, Lemna gibba and Myriophyllum sp., were exposed to 0.1--100 uL/L of creosote in 12,000 L artificial ponds. Creosote was introduced into the mesocosms using different dosing schemes to simulate leaching and spill events. The pulse amplitude modulated fluorescence technique was used to measure several parameters from plants in situ during a 60-day exposure. Chlorophyll fluorescence parameters were compared to creosote effects on population-level growth. Chlorophyll fluorescence was inhibited by creosote at concentrations above 3 uL/L, which also caused a similar inhibition of plant growth in the mesocosms. However, chlorophyll fluorescence was more sensitive than growth endpoints at low creosote concentrations. The chlorophyll fluorescence assay also detected damage to the photosynthetic apparatus in plants after only a few days exposure to creosote. Thus, chlorophyll fluorescence from plants exposed to creosote was well correlated with environmentally relevant endpoints at the population level. The effects of the different dosing schemes on creosote toxicity will also be discussed.

  13. Expression Profiling of Development Related Genes in Rice Plants Ectopically Expressing AtTOR.

    PubMed

    Bakshi, Achala; Moin, Mazahar; Datla, Raju; Kirti, P B

    2017-08-17

    Expression analysis of genes associated with development at different growth stages such as shoot apical meristem (SAM), root apical meristem (RAM), shoot and root tissues 10 DAG, flowers and grains of two high expression transgenic lines of rice ectopically expressing AtTOR revealed the involvement of AtTOR in transcriptional regulation of these genes. We have observed that in the SAM of these two selected lines, TR-2.24 and TR-15.1, OsFON1 and OsFON4 (orthologs of AtCLV1 and AtCLV3, respectively), OsKNOX2, OsKNOX3 and OsWOX3 became up-regulated. The up-regulation of OsFON1 and OsFON4 is likely to be involved in the maintenance of effective meristem size of the inflorescence and phyllotaxis. The grains and spikes of transgenic plants exhibited enhanced transcript levels of OsMADS1, OsMADS6, and OsMADS29 further implicating the role of TOR in modulating the expression of the genes in rice grain formation and development. Moreover, the up-regulation of auxin transporter, PIN1c in RAM and roots derived from seedlings 10 DAG showed the involvement of TOR in root development. The seeds of two high expression lines also showed increased expression of OSE2 and GAMYB transcription factors involved in seed development. In summary, the present study, by heterologous expression of AtTOR in rice, demonstrated the involvement of TOR in regulating genes involved in various growth and developmental stages of rice plant and also in photosynthesis, productivity related functions and water-use efficiency.

  14. Effects of nitrogen form on growth, CO2 assimilation, chlorophyll fluorescence, and photosynthetic electron allocation in cucumber and rice plants*

    PubMed Central

    Zhou, Yan-hong; Zhang, Yi-li; Wang, Xue-min; Cui, Jin-xia; Xia, Xiao-jian; Shi, Kai; Yu, Jing-quan

    2011-01-01

    Cucumber and rice plants with varying ammonium (NH4 +) sensitivities were used to examine the effects of different nitrogen (N) sources on gas exchange, chlorophyll (Chl) fluorescence quenching, and photosynthetic electron allocation. Compared to nitrate (NO3 −)-grown plants, cucumber plants grown under NH4 +-nutrition showed decreased plant growth, net photosynthetic rate, stomatal conductance, intercellular carbon dioxide (CO2) level, transpiration rate, maximum photochemical efficiency of photosystem II, and O2-independent alternative electron flux, and increased O2-dependent alternative electron flux. However, the N source had little effect on gas exchange, Chl a fluorescence parameters, and photosynthetic electron allocation in rice plants, except that NH4 +-grown plants had a higher O2-independent alternative electron flux than NO3 −-grown plants. NO3 − reduction activity was rarely detected in leaves of NH4 +-grown cucumber plants, but was high in NH4 +-grown rice plants. These results demonstrate that significant amounts of photosynthetic electron transport were coupled to NO3 − assimilation, an effect more significant in NO3 −-grown plants than in NH4 +-grown plants. Meanwhile, NH4 +-tolerant plants exhibited a higher demand for the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) for NO3 − reduction, regardless of the N form supplied, while NH4 +-sensitive plants had a high water-water cycle activity when NH4 + was supplied as the sole N source. PMID:21265044

  15. Effects of nitrogen form on growth, CO₂ assimilation, chlorophyll fluorescence, and photosynthetic electron allocation in cucumber and rice plants.

    PubMed

    Zhou, Yan-hong; Zhang, Yi-li; Wang, Xue-min; Cui, Jin-xia; Xia, Xiao-jian; Shi, Kai; Yu, Jing-quan

    2011-02-01

    Cucumber and rice plants with varying ammonium (NH(4)(+)) sensitivities were used to examine the effects of different nitrogen (N) sources on gas exchange, chlorophyll (Chl) fluorescence quenching, and photosynthetic electron allocation. Compared to nitrate (NO(3)(-))-grown plants, cucumber plants grown under NH(4)(+)-nutrition showed decreased plant growth, net photosynthetic rate, stomatal conductance, intercellular carbon dioxide (CO(2)) level, transpiration rate, maximum photochemical efficiency of photosystem II, and O(2)-independent alternative electron flux, and increased O(2)-dependent alternative electron flux. However, the N source had little effect on gas exchange, Chl a fluorescence parameters, and photosynthetic electron allocation in rice plants, except that NH(4)(+)-grown plants had a higher O(2)-independent alternative electron flux than NO(3)(-)-grown plants. NO(3)(-) reduction activity was rarely detected in leaves of NH(4)(+)-grown cucumber plants, but was high in NH(4)(+)-grown rice plants. These results demonstrate that significant amounts of photosynthetic electron transport were coupled to NO(3)(-) assimilation, an effect more significant in NO(3)(-)-grown plants than in NH(4)(+)-grown plants. Meanwhile, NH(4)(+)-tolerant plants exhibited a higher demand for the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) for NO(3)(-) reduction, regardless of the N form supplied, while NH(4)(+)-sensitive plants had a high water-water cycle activity when NH(4)(+) was supplied as the sole N source.

  16. 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.

  17. OrysPSSP: a comparative Platform for Small Secreted Proteins from rice and other plants

    PubMed Central

    Pan, Bohu; Sheng, Jia; Sun, Weining; Zhao, Yinhong; Hao, Pei; Li, Xuan

    2013-01-01

    Plants have large diverse families of small secreted proteins (SSPs) that play critical roles in the processes of development, differentiation, defense, flowering, stress response, symbiosis, etc. Oryza sativa is one of the major crops worldwide and an excellent model for monocotyledonous plants. However, there had not been any effort to systematically analyze rice SSPs. Here, we constructed a comparative platform, OrysPSSP (http://www.genoportal.org/PSSP/index.do), involving >100 000 SSPs from rice and 25 plant species. OrysPSSP is composed of a core SSP database and a dynamic web interface that integrates a variety of user tools and resources. The current release (v0530) of core SSP database contains a total of 101 048 predicted SSPs, which were generated through a rigid computation/curation pipeline. The web interface consists of eight different modules, providing users with rich resources/functions, e.g. browsing SSP by chromosome, searching and filtering SSP, validating SSP with omics data, comparing SSP among multiple species and querying core SSP database with BLAST. Some cases of application are discussed to demonstrate the utility of OrysPSSP. OrysPSSP serves as a comprehensive resource to explore SSP on the genome scale and across the phylogeny of plant species. PMID:23203890

  18. Genome-wide profiling of genetic variation in Agrobacterium-transformed rice plants*#

    PubMed Central

    Li, Wen-xu; Wu, San-ling; Liu, Yan-hua; Jin, Gu-lei; Zhao, Hai-jun; Fan, Long-jiang; Shu, Qing-yao

    2016-01-01

    Agrobacterium-mediated transformation has been widely used in producing transgenic plants, and was recently used to generate “transgene-clean” targeted genomic modifications coupled with the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas9) system. Although tremendous variation in morphological and agronomic traits, such as plant height, seed fertility, and grain size, was observed in transgenic plants, the underlying mechanisms are not yet well understood, and the types and frequency of genetic variation in transformed plants have not been fully disclosed. To reveal the genome-wide variation in transformed plants, we sequenced the genomes of five independent T0 rice plants using next-generation sequencing (NGS) techniques. Bioinformatics analyses followed by experimental validation revealed the following: (1) in addition to transfer-DNA (T-DNA) insertions, three transformed plants carried heritable plasmid backbone DNA of variable sizes (855–5216 bp) and in different configurations with the T-DNA insertions (linked or apart); (2) each transgenic plant contained an estimated 338–1774 independent genetic variations (single nucleotide variations (SNVs) or small insertion/deletions); and (3) 2–6 new Tos17 insertions were detected in each transformed plant, but no other transposable elements or bacterial genomic DNA. PMID:27921404

  19. Genome-wide profiling of genetic variation in Agrobacterium-transformed rice plants.

    PubMed

    Li, Wen-Xu; Wu, San-Ling; Liu, Yan-Hua; Jin, Gu-Lei; Zhao, Hai-Jun; Fan, Long-Jiang; Shu, Qing-Yao

    Agrobacterium-mediated transformation has been widely used in producing transgenic plants, and was recently used to generate "transgene-clean" targeted genomic modifications coupled with the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas9) system. Although tremendous variation in morphological and agronomic traits, such as plant height, seed fertility, and grain size, was observed in transgenic plants, the underlying mechanisms are not yet well understood, and the types and frequency of genetic variation in transformed plants have not been fully disclosed. To reveal the genome-wide variation in transformed plants, we sequenced the genomes of five independent T0 rice plants using next-generation sequencing (NGS) techniques. Bioinformatics analyses followed by experimental validation revealed the following: (1) in addition to transfer-DNA (T-DNA) insertions, three transformed plants carried heritable plasmid backbone DNA of variable sizes (855-5216 bp) and in different configurations with the T-DNA insertions (linked or apart); (2) each transgenic plant contained an estimated 338-1774 independent genetic variations (single nucleotide variations (SNVs) or small insertion/deletions); and (3) 2-6 new Tos17 insertions were detected in each transformed plant, but no other transposable elements or bacterial genomic DNA.

  20. Plant available silicon in South-east Asian rice paddy soils - relevance of agricultural practice and of abiotic factors

    NASA Astrophysics Data System (ADS)

    Marxen, A.; Klotzbücher, T.; Vetterlein, D.; Jahn, R.

    2012-12-01

    Background Silicon (Si) plays a crucial role in rice production. Si content of rice plants exceeds the content of other major nutrients such as nitrogen, phosphorous or potassium. Recent studies showed that in some environments external supply of Si can enhance the growth of rice plants. Rice plants express specific Si transporters to absorb Si from soil solutions in form of silicic acid, which precipitates in tissue cells forming amorphous silica bodies, called phytoliths. The phytoliths are returned to soils with plant residues. They might be a main source of plant available silicic acid in soils. Aims In this study we assess the effects of rice paddy cultivation on the stocks of `reactive` Si fractions in mineral topsoils of rice paddy fields in contrasting landscapes. The `reactive` Si fractions are presumed to determine the release of plant-available silicic acid in soils. We consider the relevance of abiotic factors (mineral assemblage; soil weathering status) and agricultural practice for these fractions. Agricultural practices, which were assumed to affect the stocks of `reactive` Si were (i) the usage of different rice varieties (which might differ in Si demand), (ii) straw residue management (i.e., whether straw residues are returned to the fields or removed and used e.g. as fodder), and (iii) yield level and number of crops per year. Material and methods Soils (top horizon of about 0-20 cm depth) were sampled from rice paddy fields in 2 mountainous and 5 lowland landscapes of contrasting geologic conditions in Vietnam and the Philippines. Ten paddy fields were sampled per landscape. The rice paddy management within landscapes differed when different farmers and/or communities managed the fields. We analysed the following fractions of `reactive` Si in the soils: acetate-extractable Si (dissolved and easily exchangeable Si), phosphate-extractable Si (adsorbed Si), oxalate extractable Si (Si associated with poorly-ordered sesquioxides), NaOH extractable Si

  1. Photo acoustic study of plants exposed to varying light intensity growth conditions: Spectral and morphological changes

    NASA Astrophysics Data System (ADS)

    Mesquita, R. C.; Barja, P. R.; da Silva, E. C.; Mansanares, A. M.

    2005-06-01

    In this paper we describe results of photo acoustic (PA) measurements carried out on various plants exposed to varying light intensity conditions. Depending on the species and light intensity conditions, the PA absorption spectra show differences in peaks associated with pigments and the cuticle. These differences are related to the spatial distribution of the pigments that differs from plant to plant. We have also performed systematic study of oxygen evolution at different wavelengths. The obtained oxygen spectra are equivalent to the action spectra usually acquired by determining the CO2 uptake and energy storage. The intensities of oxygen spectra exhibit differences depending on distinct morphology of plant.

  2. Evaluation of host-plant resistance of selected rice genotypes to the rice water weevil (Coleoptera:Curculionidae)

    USDA-ARS?s Scientific Manuscript database

    The rice water weevil (RWW), Lissorhoptrus oryzophilus Kuschel, is the most important economic insect pest of rice in the United States. Currently, management of RWW mainly depends upon the use of insecticides due to the lack of effective alternate management tactics. A three year field study was co...

  3. MicroRNA-mediated regulation of gene expression in the response of rice plants to fungal elicitors.

    PubMed

    Baldrich, Patricia; Campo, Sonia; Wu, Ming-Tsung; Liu, Tze-Tze; Hsing, Yue-Ie Caroline; San Segundo, Blanca

    2015-01-01

    MicroRNAs (miRNAs) are small non-coding RNAs that have important regulatory functions in plant growth, development, and response to abiotic stress. Increasing evidence also supports that plant miRNAs contribute to immune responses to pathogens. Here, we used deep sequencing of small RNA libraries for global identification of rice miRNAs that are regulated by fungal elicitors. We also describe 9 previously uncharacterized miRNAs in rice. Combined small RNA and degradome analyses revealed regulatory networks enriched in elicitor-regulated miRNAs supported by the identification of their corresponding target genes. Specifically, we identified an important number of miRNA/target gene pairs involved in small RNA pathways, including miRNA, heterochromatic and trans-acting siRNA pathways. We present evidence for miRNA/target gene pairs implicated in hormone signaling and cross-talk among hormone pathways having great potential in regulating rice immunity. Furthermore, we describe miRNA-mediated regulation of Conserved-Peptide upstream Open Reading Frame (CPuORF)-containing genes in rice, which suggests the existence of a novel regulatory network that integrates miRNA and CPuORF functions in plants. The knowledge gained in this study will help in understanding the underlying regulatory mechanisms of miRNAs in rice immunity and develop appropriate strategies for rice protection.

  4. Growth and certain chemical constituents of tobacco plants exposed to air ions

    NASA Astrophysics Data System (ADS)

    Barthakur, N. N.; Arnold, N. P.

    1988-06-01

    Controlled experiments were performed in Faraday cages on the effects of positive and negative air ions on flue-cured tobacco plants. Continuous exposures for 15 days to air ions showed no significant differences in any plant growth characteristic between the treated and control plants. Standard errors in the measurement of the growth parameters for ion exposed plants were, however, consistently higher than those of control plants. Spatial variation in concentration gradients of air ions produced by corona discharge might have contributed to masking of the relatively small effects of air ions on biological organisms observed in previous experiments in this laboratory. No significant difference was observed between the experimental and control plants in nicotine, total alkaloid, and reducing sugar contents. Total nitrogen content was slightly higher for treated than control plants.

  5. 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

  6. Dynamic metabolic responses of brown planthoppers towards susceptible and resistant rice plants.

    PubMed

    Liu, Caixiang; Du, Ba; Hao, Fuhua; Lei, Hehua; Wan, Qianfen; He, Guangcun; Wang, Yulan; Tang, Huiru

    2017-10-01

    Brown planthopper (Nilaparvata lugens Stål, BPH) causes huge economic losses in rice-growing regions, and new strategies for combating BPH are required. To understand how BPHs respond towards BPH-resistant plants, we systematically analysed the metabolic differences between BPHs feeding on the resistant and susceptible plants using NMR and GC-FID/MS. We also measured the expression of some related genes involving glycolysis and biosyntheses of trehalose, amino acids, chitin and fatty acids using real-time PCR. BPH metabonome was dominated by more than 60 metabolites including fatty acids, amino acids, carbohydrates, nucleosides/nucleotides and TCA cycle intermediates. After initial 12 h, BPHs feeding on the resistant plants had lower levels of amino acids, glucose, fatty acids and TCA cycle intermediates than on the susceptible ones. The levels of these metabolites recovered after 24 h feeding. This accompanied with increased level in trehalose, choline metabolites and nucleosides/nucleotides compared with BPH feeding on the susceptible plants. Decreased levels of BPH metabolites at the early feeding probably resulted from less BPH uptakes of sap from resistant plants and recovery of BPH metabolites at the later stage probably resulted from their adaptation to the adverse environment with their increased hopping frequency to ingest more sap together with contributions from yeast-like symbionts in BPHs. Throughout 96 h, BPH feeding on the resistant plants showed significant up-regulation of chitin synthase catalysing biosynthesis of chitin for insect exoskeleton, peritrophic membrane lining gut and tracheae. These findings provided useful metabolic information for understanding the BPH-rice interactions and perhaps for developing new BPH-combating strategies. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  7. Silicon isotope fractionation between rice plants and nutrient solution and its significance to the study of the silicon cycle

    NASA Astrophysics Data System (ADS)

    Ding, T. P.; Tian, S. H.; Sun, L.; Wu, L. H.; Zhou, J. X.; Chen, Z. Y.

    2008-12-01

    The silicon isotope fractionation between rice plant and nutrient solution was studied experimentally. Rice plants were grown to maturity with the hydroponic culture in a naturally lit glasshouse. The nutrient solution was sampled for 14 times during the whole rice growth period. The rice plants were collected at various growth stages and different parts of the plants were sampled separately. The silica contents of the samples were determined by the gravimetric method and the silicon isotope compositions were measured using the SiF 4 method. In the growth process, the silicon content in the nutrient solution decreased gradually from 16 mM at starting stage to 0.1-0.2 mM at harvest and the amount of silica in single rice plant increased gradually from 0.00013 g at start to 4.329 g at harvest. Within rice plant the SiO 2 fraction in roots reduced continuously from 0.23 at the seedling stage, through 0.12 at the tiller stage, 0.05 at the jointing stage, 0.023 at the heading stage, to 0.009 at the maturity stage. Accordingly, the fraction of SiO 2 in aerial parts increased from 0.77, through 0.88, 0.95, 0.977, to 0.991 for the same stages. The silicon content in roots decreased from the jointing stage, through the heading stage, to the maturity stage, parallel to the decrease of silicon content in the nutrient solution. At the maturity stage, the silicon content increased from roots, through stem and leaves, to husks, but decreased drastically from husks to grains. These observations show that transpiration and evaporation may play an important role in silica transportation and precipitation within rice plants. It was observed that the δ30Si of the nutrient solution increased gradually from -0.1‰ at start to 1.5‰ at harvest, and the δ30Si of silicon absorbed by bulk rice plant increased gradually from -1.72‰ at start to -0.08‰ at harvest, reflecting the effect of the kinetic silicon isotope fractionation during silicon absorption by rice plants from nutrient

  8. 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.

  9. Mapping paddy rice planting areas through time series analysis of MODIS land surface temperature and vegetation index data

    NASA Astrophysics Data System (ADS)

    Zhang, Geli; Xiao, Xiangming; Dong, Jinwei; Kou, Weili; Jin, Cui; Qin, Yuanwei; Zhou, Yuting; Wang, Jie; Menarguez, Michael Angelo; Biradar, Chandrashekhar

    2015-08-01

    Knowledge of the area and spatial distribution of paddy rice is important for assessment of food security, management of water resources, and estimation of greenhouse gas (methane) emissions. Paddy rice agriculture has expanded rapidly in northeastern China in the last decade, but there are no updated maps of paddy rice fields in the region. Existing algorithms for identifying paddy rice fields are based on the unique physical features of paddy rice during the flooding and transplanting phases and use vegetation indices that are sensitive to the dynamics of the canopy and surface water content. However, the flooding phenomena in high latitude area could also be from spring snowmelt flooding. We used land surface temperature (LST) data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor to determine the temporal window of flooding and rice transplantation over a year to improve the existing phenology-based approach. Other land cover types (e.g., evergreen vegetation, permanent water bodies, and sparse vegetation) with potential influences on paddy rice identification were removed (masked out) due to their different temporal profiles. The accuracy assessment using high-resolution images showed that the resultant MODIS-derived paddy rice map of northeastern China in 2010 had a high accuracy (producer and user accuracies of 92% and 96%, respectively). The MODIS-based map also had a comparable accuracy to the 2010 Landsat-based National Land Cover Dataset (NLCD) of China in terms of both area and spatial pattern. This study demonstrated that our improved algorithm by using both thermal and optical MODIS data, provides a robust, simple and automated approach to identify and map paddy rice fields in temperate and cold temperate zones, the northern frontier of rice planting.

  10. Mapping paddy rice planting areas through time series analysis of MODIS land surface temperature and vegetation index data

    PubMed Central

    Zhang, Geli; Xiao, Xiangming; Dong, Jinwei; Kou, Weili; Jin, Cui; Qin, Yuanwei; Zhou, Yuting; Wang, Jie; Menarguez, Michael Angelo; Biradar, Chandrashekhar

    2016-01-01

    Knowledge of the area and spatial distribution of paddy rice is important for assessment of food security, management of water resources, and estimation of greenhouse gas (methane) emissions. Paddy rice agriculture has expanded rapidly in northeastern China in the last decade, but there are no updated maps of paddy rice fields in the region. Existing algorithms for identifying paddy rice fields are based on the unique physical features of paddy rice during the flooding and transplanting phases and use vegetation indices that are sensitive to the dynamics of the canopy and surface water content. However, the flooding phenomena in high latitude area could also be from spring snowmelt flooding. We used land surface temperature (LST) data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor to determine the temporal window of flooding and rice transplantation over a year to improve the existing phenology-based approach. Other land cover types (e.g., evergreen vegetation, permanent water bodies, and sparse vegetation) with potential influences on paddy rice identification were removed (masked out) due to their different temporal profiles. The accuracy assessment using high-resolution images showed that the resultant MODIS-derived paddy rice map of northeastern China in 2010 had a high accuracy (producer and user accuracies of 92% and 96%, respectively). The MODIS-based map also had a comparable accuracy to the 2010 Landsat-based National Land Cover Dataset (NLCD) of China in terms of both area and spatial pattern. This study demonstrated that our improved algorithm by using both thermal and optical MODIS data, provides a robust, simple and automated approach to identify and map paddy rice fields in temperate and cold temperate zones, the northern frontier of rice planting. PMID:27667901

  11. Drying and Storage Methods Affect Cyfluthrin Concentrations in Exposed Plant Samples.

    PubMed

    Moore, M T; Kröger, R; Locke, M A

    2016-08-01

    Standard procedures do not exist for drying and storage of plant samples prior to chemical analyses. Since immediate analysis is not always possible, current research examined which plant drying and storage method yielded the highest cyfluthrin recovery rates compared to traditional mechanical freeze-drying methods. Fifteen mesocosms were planted with rice. Cyfluthrin (5 mg L(-1)) was amended into the water column of individual mesocosms. 48 h later, plant material in the water column was collected from each mesocosm. Control (mechanical freeze drying) recovery was significantly greater (p < 0.001) than all 14 combinations of drying and storage. Significant differences also existed between all 14 different combinations. Greatest cyfluthrin recoveries in non-control plants were from the freezer-greenhouse-freezer drying and storage method. Results offer evidence for the efficient plant drying and storage methods prior to cyfluthrin analysis. Future studies should perform comparable analyses on various pesticide classes to determine possible relationships.

  12. Effect of carbon nanomaterials on the germination and growth of rice plants.

    PubMed

    Nair, Remya; Mohamed, M Sheikh; Gao, Wei; Maekawa, Toru; Yoshida, Yasuhiko; Ajayan, Pulickel M; Kumar, D Sakthi

    2012-03-01

    For the successful diverse applications of different nanomaterials in life sciences, it is necessary to understand the ultimate fate, distribution and potential environmental impacts of manufactured nanomaterials. Phytotoxicity studies using higher plants is an important criterion for understanding the toxicity of engineered nanomaterials. We studied the effects of engineered carbon nanomaterials of various dimensionalities (carbon nanotubes, C60, graphene) on the germination of rice seeds. A pronounced increase in the rate of germination was observed for rice seeds in the presence of some of these carbon nanostructures, in particular the nanotubes. Increased water content was observed in the carbon nanomaterial treated seeds during germination compared to controls. The germinated seeds were then grown in a basal growth medium supplemented with carbon nanomaterials for studying their impact on further seedling growth. Treated seedlings appeared to be healthier with well-developed root and shoot systems compared to control seedlings. Our results indicate the possible use for carbon nanomaterials as enhancers in the growth of rice seedlings.

  13. Aquaporins are major determinants of water use efficiency of rice plants in the field.

    PubMed

    Nada, Reham M; Abogadallah, Gaber M

    2014-10-01

    This study aimed at specifying the reasons of unbalanced water relations of rice in the field at midday which results in slowing down photosynthesis and reducing water use efficiency (WUE) in japonica and indica rice under well-watered and droughted conditions. Leaf relative water content (RWC) decreased in the well-watered plants at midday in the field, but more dramatically in the droughted indica (75.6 and 71.4%) than japonica cultivars (85.5 and 80.8%). Gas exchange was measured at three points during the day (9:00, 13:00 and 17:00). Leaf internal CO2 (Ci) was not depleted when midday stomatal depression was highest indicating that Ci was not limiting to photosynthesis. Most aquaporins were predominantly expressed in leaves suggesting higher water permeability in leaves than in roots. The expression of leaf aquaporins was further induced by drought at 9:00 without comparable responses in roots. The data suggest that aquaporin expression in the root endodermis was limiting to water uptake. Upon removal of the radial barriers to water flow in roots, transpiration increased instantly and photosynthesis increased after 4h resulting in increasing WUE after 4h, demonstrating that WUE in rice is largely limited by the inadequate aquaporin expression profiles in roots. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  14. Leaf Lateral Asymmetry in Morphological and Physiological Traits of Rice Plant

    PubMed Central

    Yuan, Shen; Li, Yong; Peng, Shaobing

    2015-01-01

    Leaf lateral asymmetry in width and thickness has been reported previously in rice. However, the differences between the wide and narrow sides of leaf blade in other leaf morphological and physiological traits were not known. This study was conducted to quantify leaf lateral asymmetry in leaf width, leaf thickness, specific leaf weight (SLW), leaf nitrogen (N) concentration based on dry weight (Nw) and leaf area (Na), and chlorophyll meter reading (SPAD). Leaf morphological and physiological traits of the two lateral halves of the top three leaves at heading stage were measured on 23 rice varieties grown in three growing seasons in two locations. Leaf lateral asymmetry was observed in leaf width, leaf thickness, Nw, Na, and SPAD, but not in SLW. On average, the leaf width of the wide side was about 17% higher than that of the narrow side. The wide side had higher leaf thickness than the narrow side whereas the narrow side had higher Nw, Na, and SPAD than the wide side. We conclude that the narrow side of leaf blade maintained higher leaf N status than the wide side based on all N-related parameters, which implies a possibility of leaf lateral asymmetry in photosynthetic rate in rice plant. PMID:26053267

  15. Members of rice plasma membrane intrinsic proteins subfamily are involved in arsenite permeability and tolerance in plants.

    PubMed

    Mosa, Kareem A; Kumar, Kundan; Chhikara, Sudesh; Mcdermott, Joseph; Liu, Zijuan; Musante, Craig; White, Jason C; Dhankher, Om Parkash

    2012-12-01

    Rice accumulates high level of arsenic (As) in its edible parts and thus plays an important role in the transfer of As into the food chain. However, the mechanisms of As uptake and its detoxification in rice are not well understood. Recently, members of the Nodulin 26-like intrinsic protein (NIP) subfamily of plant aquaporins were shown to transport arsenite in rice and Arabidopsis. Here we report that members of the rice plasma membrane intrinsic protein (PIP) subfamily are also involved in As tolerance and transport. Based on the homology search with the mammalian AQP9 and yeast Fps1 arsenite transporters, we identified and cloned five rice PIP gene subfamily members. qRT-PCR analysis of PIPs in rice root and shoot tissues revealed a significant down regulation of transcripts encoding OsPIP1;2, OsPIP1;3, OsPIP2;4, OsPIP2;6, and OsPIP2;7 in response to arsenite treatment. Heterologous expression of OsPIP2;4, OsPIP2;6, and OsPIP2;7 in Xenopus laevis oocytes significantly increased the uptake of arsenite. Overexpression of OsPIP2;4, OsPIP2;6, and OsPIP2;7 in Arabidopsis yielded enhanced arsenite tolerance and higher biomass accumulation. Further, these transgenic plants showed no significant accumulation of As in shoot and root tissues in long term uptake assays. Whereas, short duration exposure to arsenite caused both active influx and efflux of As in the roots. The data suggests a bidirectional arsenite permeability of rice PIPs in plants. These rice PIPs genes will be highly useful for engineering important food and biofuel crops for enhanced crop productivity on contaminated soils without increasing the accumulation of toxic As in the biomass or edible tissues.

  16. DNA repair and recombination in higher plants: insights from comparative genomics of arabidopsis and rice

    PubMed Central

    2010-01-01

    Background The DNA repair and recombination (DRR) proteins protect organisms against genetic damage, caused by environmental agents and other genotoxic agents, by removal of DNA lesions or helping to abide them. Results We identified genes potentially involved in DRR mechanisms in Arabidopsis and rice using similarity searches and conserved domain analysis against proteins known to be involved in DRR in human, yeast and E. coli. As expected, many of DRR genes are very similar to those found in other eukaryotes. Beside these eukaryotes specific genes, several prokaryotes specific genes were also found to be well conserved in plants. In Arabidopsis, several functionally important DRR gene duplications are present, which do not occur in rice. Among DRR proteins, we found that proteins belonging to the nucleotide excision repair pathway were relatively more conserved than proteins needed for the other DRR pathways. Sub-cellular localization studies of DRR gene suggests that these proteins are mostly reside in nucleus while gene drain in between nucleus and cell organelles were also found in some cases. Conclusions The similarities and dissimilarities in between plants and other organisms' DRR pathways are discussed. The observed differences broaden our knowledge about DRR in the plants world, and raises the potential question of whether differentiated functions have evolved in some cases. These results, altogether, provide a useful framework for further experimental studies in these organisms. PMID:20646326

  17. NADPH oxidases regulate septin-mediated cytoskeletal remodeling during plant infection by the rice blast fungus

    PubMed Central

    Ryder, Lauren S.; Dagdas, Yasin F.; Mentlak, Thomas A.; Kershaw, Michael J.; Thornton, Christopher R.; Schuster, Martin; Chen, Jisheng; Wang, Zonghua; Talbot, Nicholas J.

    2013-01-01

    The rice blast fungus Magnaporthe oryzae infects plants with a specialized cell called an appressorium, which uses turgor to drive a rigid penetration peg through the rice leaf cuticle. Here, we show that NADPH oxidases (Nox) are necessary for septin-mediated reorientation of the F-actin cytoskeleton to facilitate cuticle rupture and plant cell invasion. We report that the Nox2–NoxR complex spatially organizes a heteroligomeric septin ring at the appressorium pore, required for assembly of a toroidal F-actin network at the point of penetration peg emergence. Maintenance of the cortical F-actin network during plant infection independently requires Nox1, a second NADPH oxidase, which is necessary for penetration hypha elongation. Organization of F-actin in appressoria is disrupted by application of antioxidants, whereas latrunculin-mediated depolymerization of appressorial F-actin is competitively inhibited by reactive oxygen species, providing evidence that regulated synthesis of reactive oxygen species by fungal NADPH oxidases directly controls septin and F-actin dynamics. PMID:23382235

  18. Germination and early plant development of ten plant species exposed to titanium dioxide and cerium oxide nanoparticles

    EPA Science Inventory

    Ten agronomic plant species were exposed to different concentrations of nano titanium dioxide (nTiO2) or nano cerium oxide (nCeO2) (0, 250, 500 and 1000 mg/L) to examine potential effects on germination and early seedling development. We modified a standard test protocol develop...

  19. QTLs for heading date and plant height under multiple environments in rice.

    PubMed

    Han, Zhongmin; Hu, Wei; Tan, Cong; Xing, Yongzhong

    2017-02-01

    Both heading date and plant height are important traits related to grain yield in rice. In this study, a recombinant inbred lines (RILs) population was used to map quantitative trait loci (QTLs) for both traits under 3 long-day (LD) environments and 1 short-day (SD) environment. A total of eight QTLs for heading date and three QTLs for plant height were detected by composite interval mapping under LD conditions. Additional one QTL for heading date and three QTLs for plant height were identified by Two-QTL model under LD conditions. Among them, major QTLs qHd7.1, qHd7.2 and qHd8 for heading date, and qPh1 and qPh7.1 for plant height were commonly detected. qHd7.1 and qHd7.2 were mapped to small regions of less than 1 cM. Genome position comparison of previously cloned genes with QTLs detected in this study revealed that qHd5 and qPh3.1 were two novel QTLs. The alleles of these QTLs increasing trait values were dispersed in both parents, which well explained the transgressive segregation observed in this population. In addition, the interaction between qHd7.1 and qHd8 was detected under all LD conditions. Multiple-QTL model analysis revealed that all QTLs and their interactions explained over 80% of heading date variation and 50% of plant height variation. Two heading date QTLs were detected under SD condition. Of them, qHd10 were commonly identified under LD condition. The difference in QTL detection between LD and SD conditions indicated most heading date QTLs are sensitive to photoperiod. These findings will benefit breeding design for heading date and plant height in rice.

  20. Effects of the Magnetic Resonance Imaging Contrast Agent Gd-DTPA on Plant Growth and Root Imaging in Rice

    PubMed Central

    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. PMID:24945975

  1. 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.

  2. Mutualistic fungal endophytes produce phytohormones and organic acids that promote japonica rice plant growth under prolonged heat stress*

    PubMed Central

    Waqas, Muhammad; Khan, Abdul Latif; Shahzad, Raheem; Ullah, Ihsan; Khan, Abdur Rahim; Lee, In-Jung

    2015-01-01

    This study identifies the potential role in heat-stress mitigation of phytohormones and other secondary metabolites produced by the endophytic fungus Paecilomyces formosus LWL1 in japonica rice cultivar Dongjin. The japonica rice was grown in controlled chamber conditions with and without P. formosus LWL1 under no stress (NS) and prolonged heat stress (HS) conditions. Endophytic association under NS and HS conditions significantly improved plant growth attributes, such as plant height, fresh weight, dry weight, and chlorophyll content. Furthermore, P. formosus LWL1 protected the rice plants from HS compared with controls, indicated by the lower endogenous level of stress-signaling compounds such as abscisic acid (25.71%) and jasmonic acid (34.57%) and the increase in total protein content (18.76%–33.22%). Such fungal endophytes may be helpful for sustainable crop production under high environmental temperatures. PMID:26642184

  3. PlantGM: a database for genetic markers in rice (Oryza sativa) and Chinese cabbage (Brassica rapa)

    PubMed Central

    Kim, Chang Kug; Kim, Jung Sun; Lee, Gang Seob; Park, Beom Seok; Hahn, Jang Ho

    2008-01-01

    The Plant Genetic Map Database (PlantGM) has been developed as a web-based system which provides information about genetic markers in rice (Oryza sativa) and Chinese cabbage (Brassica rapa). The database has three major parts and functions; (1) Map Search, (2) Marker Search, and (3) QTL Search. At present, the database provides characterization information for about 3258 genetic markers. It has 2800 RFLP and 112 QTL markers related to rice in addition to 321 RFLP and 25 PCR-based markers for Chinese cabbage. In addition, a genetic linkage map was also constructed by using 1,054 markers from 2,912 markers in rice. Availability The database is available for free at http://www.niab.go.kr/nabic/PlantGM PMID:19238232

  4. Expression of rice thaumatin-like protein gene in transgenic banana plants enhances resistance to fusarium wilt.

    PubMed

    Mahdavi, F; Sariah, M; Maziah, M

    2012-02-01

    The possibility of controlling Fusarium wilt--caused by Fusarium oxysporum sp. cubensec (race 4)--was investigated by genetic engineering of banana plants for constitutive expression of rice thaumatin-like protein (tlp) gene. Transgene was introduced to cauliflower-like bodies' cluster, induced from meristemic parts of male inflorescences, using particle bombardment with plasmid carrying a rice tlp gene driving by the CaMV 35S promoter. Hygromycin B was used as the selection reagent. The presence and integration of rice tlp gene in genomic DNA confirmed by PCR and Southern blot analyses. RT-PCR revealed the expression of transgene in leaf and root tissues in transformants. Bioassay of transgenic banana plants challenged with Fusarium wilt pathogen showed that expression of TLP enhanced resistance to F. oxysporum sp. cubensec (race 4) compared to control plants.

  5. 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

  6. 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.

  7. Traditional and modern plant breeding methods with examples in rice (Oryza sativa L.).

    PubMed

    Breseghello, Flavio; Coelho, Alexandre Siqueira Guedes

    2013-09-04

    Plant breeding can be broadly defined as alterations caused in plants as a result of their use by humans, ranging from unintentional changes resulting from the advent of agriculture to the application of molecular tools for precision breeding. The vast diversity of breeding methods can be simplified into three categories: (i) plant breeding based on observed variation by selection of plants based on natural variants appearing in nature or within traditional varieties; (ii) plant breeding based on controlled mating by selection of plants presenting recombination of desirable genes from different parents; and (iii) plant breeding based on monitored recombination by selection of specific genes or marker profiles, using molecular tools for tracking within-genome variation. The continuous application of traditional breeding methods in a given species could lead to the narrowing of the gene pool from which cultivars are drawn, rendering crops vulnerable to biotic and abiotic stresses and hampering future progress. Several methods have been devised for introducing exotic variation into elite germplasm without undesirable effects. Cases in rice are given to illustrate the potential and limitations of different breeding approaches.

  8. 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

  9. Relationship between xanthophyll cycle and non-photochemical quenching in rice (Oryza sativa L.) plants in response to light stress.

    PubMed

    Vaz, Janet; Sharma, Prabhat K

    2011-01-01

    Thirty days old rice plants grown under low and moderate light conditions were transferred to full sunlight to observe the extent of photoinhibitory damage and protective mechanism, and the relationship between xanthophyll cycle and nonphotochemical quenching (qN) under changing light environment. Control plants (low, moderate and sun grown) exhibited similar Fv/Fm ratio, indicating similar photosynthetic efficiency prior to light stress. On exposure to the high light treatment, low light grown plants exhibited faster and higher degree of photoinhibition compared to moderate and high light grown plants. Moderate and high light grown plants showed relatively less photoinhibition and also showed higher qN, indicating better capacity of energy dissipation. Increase in qN in moderate light and sun grown plants was accompanied by conversion of violaxanthin (V) to antheraxanthin (A) and zeaxanthin (Z) indicating operation of Z-dependent thermal dissipation. Rice plants fed with ascorbate (AsA), a stimulator of the de-epoxidation state of V to Z, showed higher Fv/Fm ratio and qN than the plants fed with dithiothreitol (DTT) an inhibitor of xanthophyll cycle. This indicated that an increased amount of energy reached PS II reaction centre, due to absence of A and Z formation, thereby causing greater damage to photosynthesis in DTT fed rice plants. The present data confirmed the relationship between qN and Z in dissipating the excess light energy, thereby protecting plants against photodamage.

  10. Growth and foliar nitrogen status of four plant species exposed to atmospheric ammonia.

    PubMed

    Adrizal; Patterson, P H; Hulet, R M; Bates, R M

    2006-01-01

    A chamber study was conducted to evaluate the growth response and leaf nitrogen (N) status of four plant species exposed to continuous ammonia (NH3) for 12 weeks (wk). This was intended to evaluate appropriate plant species that could be used to trap discharged NH3 from the exhaust fans in poultry feeding operations before moving off-site. Two hundred and forty bare-root plants of four species (Juniperus virginiana (red cedar), Gleditsia triacanthos var. inermis (thornless honey locust), Populus sp. (hybrid poplar), and Phalaris arundinacea (reed canary grass) were transplanted into 4- or 8-L polyethylene pots and grown in four environmentally controlled chambers. Plants placed in two of the four chambers received continuous exposure to anhydrous NH3 at 4 to 5 ppm while plants in another two chambers received no NH3. In each of the four chambers, 2 to 4 plants per species received no fertilizer while the rest of the plants were fertilized with a 100 ppm solution containing 21% N, 7% phosphorus, and 7% potassium. The results showed that honey locust was the fastest-growing species. The superior growth of honey locust among all species was also supported by its total biomass, root, and root dry matter (DM) weights. For all species there was a trend for plants exposed to NH3 to have greater leaf DM than their non-exposed counterparts at 6 (43.0 vs. 30.8%; P = 0.09) and 12 wk (47.9 vs. 36.6%; P = 0.07), and significantly greater (P exposed to NH3. Numerically greater leaf DM due to NH3 exposure was also consistently measured in poplar at both sampling periods. Hybrid poplar, as well as honey locust and reed canary grass, deposited 1.5 to 2-fold greater N in their leaves than red cedar tissues as a result of NH3 exposure compared to non-exposed plants. Regardless of the effect of NH3 on foliar color and damage score of the plants, the increase of foliar N content (g 100 g-1 of fresh foliage

  11. Short-term effects of compost amendment on the fractionation of cadmium in soil and cadmium accumulation in rice plants.

    PubMed

    Juang, Kai-Wei; Ho, Pei-Chi; Yu, Chun-Hui

    2012-06-01

    We used a sequential extraction to investigate the effects of compost amendment on Cd fractionation in soil during different incubation periods in order to assess Cd stabilization in soil over time. Pot experiments using rice plants growing on Cd-spiked soils were carried out to evaluate the influence of compost amendment on plant growth and Cd accumulation by rice. Two agricultural soils (Pinchen and Lukang) of Taiwan were used for the experiments. The relationship between the redistribution of Cd fractions and the reduction of plant Cd concentration due to compost amendment was then investigated. Compost amendment in Pinchen soil (lower pH) could transform exchangeable Cd into the Fe- and Mn-oxide-bound forms. With increasing incubation time, exchangeable Cd tended to transform into carbonate- and Fe- and Mn-oxide-bound fractions. In Lukang soil (higher pH), carbonate- and Fe- and Mn-oxide-bonded Cd were the main fractions. Exchangeable Cd was low. Compost amendment transformed the carbonate-bound form into the Fe and Mn oxide form. Pot experiments of rice plants showed that compost amendment enhanced plant growth more in Pinchen soil than in Lukang soil. Compost amendment could significantly reduce Cd accumulation in rice roots in both Pinchen and Lukang soils and restrict internal transport of Cd from the roots to the shoots. Because exchangeable Cd can be transformed into the stronger bonded fractions quickly in Pinchen soil, a reduction of Cd accumulation in rice due to compost amendment of Pinchen soil was significant by 45 days of growth. However, carbonate-bonded fractions in Lukang soil may provide a source of available Cd to rice plants, and exchangeable and carbonate-bonded fractions are transformed into the other fractions slowly. Thus, reduction of Cd accumulation by rice due to compost amendment in Lukang soil was significant by 75 days of growth. The results of the study suggest that the effectiveness of compost amendment used for stabilization of

  12. Detection of nitrogen-overfertilized rice plants with leaf positional difference in hyperspectral vegetation index*

    PubMed Central

    Zhou, Qi-fa; Liu, Zhan-yu; Huang, Jing-feng

    2010-01-01

    The main objective of this work was to compare the applicability of the single leaf (the uppermost leaf L1 and the third uppermost leaf L3) modified simple ratio (mSR705 index) and the leaf positional difference in the vegetation index between L1 and L3 (mSR705L1−mSR705L3) in detecting nitrogen (N)-overfertilized rice plants. A field experiment consisting of three rice genotypes and five N fertilization levels (0, 75, 180, 285, and 390 kg N/ha) was conducted at Xiaoshan, Hangzhou, Zhejiang Province, China in 2008. The hyperspectral reflectance (350–2500 nm) and the chlorophyll concentration (ChlC) of L1 and L3 were measured at different stages. The mSR705L1 and mSR705L3 indices appeared not to be highly sensitive to the N rates, especially when the N rate was high (above 180 kg N/ha). The mean mSR705L1−mSR705L3 across the genotypes increased significantly (P<0.05) or considerably from 180 to 285 kg N/ha treatment and from 285 to 390 kg N/ha treatment at all the stages. Also, use of the difference (mSR705L1−mSR705L3) greatly reduced the influence of the stages and genotypes in assessing the N status with reflectance data. The results of this study show that the N-overfertilized rice plants can be effectively detected with the leaf positional difference in the mSR705 index. PMID:20506579

  13. Polycomb Protein OsFIE2 Affects Plant Height and Grain Yield in Rice

    PubMed Central

    Sheng, Zhonghua; Jiao, Guiai; Tang, Shaoqing; Luo, Ju; Hu, Peisong

    2016-01-01

    Polycomb group (PcG) proteins have been shown to affect growth and development in plants. To further elucidate their role in these processes in rice, we isolated and characterized a rice mutant which exhibits dwarfism, reduced seed setting rate, defective floral organ, and small grains. Map-based cloning revealed that abnormal phenotypes were attributed to a mutation of the Fertilization Independent Endosperm 2 (OsFIE2) protein, which belongs to the PcG protein family. So we named the mutant as osfie2-1. Histological analysis revealed that the number of longitudinal cells in the internodes decreased in osfie2-1, and that lateral cell layer of the internodes was markedly thinner than wild-type. In addition, compared to wild-type, the number of large and small vascular bundles decreased in osfie2-1, as well as cell number and cell size in spikelet hulls. OsFIE2 is expressed in most tissues and the coded protein localizes in both nucleus and cytoplasm. Yeast two-hybrid and bimolecular fluorescence complementation assays demonstrated that OsFIE2 interacts with OsiEZ1 which encodes an enhancer of zeste protein previously identified as a histone methylation enzyme. RNA sequencing-based transcriptome profiling and qRT-PCR analysis revealed that some homeotic genes and genes involved in endosperm starch synthesis, cell division/expansion and hormone synthesis and signaling are differentially expressed between osfie2-1 and wild-type. In addition, the contents of IAA, GA3, ABA, JA and SA in osfie2-1 are significantly different from those in wild-type. Taken together, these results indicate that OsFIE2 plays an important role in the regulation of plant height and grain yield in rice. PMID:27764161

  14. Biocontrol and plant growth promoting activities of a Streptomyces corchorusii strain UCR3-16 and preparation of powder formulation for application as biofertilizer agents for rice plant.

    PubMed

    Tamreihao, K; Ningthoujam, Debananda S; Nimaichand, Salam; Singh, Elangbam Shanta; Reena, Pascal; Singh, Salam Herojeet; Nongthomba, Upendra

    2016-11-01

    Streptomyces corchorusii strain UCR3-16, obtained from rice rhizospheric soils showed antifungal activities against 6 major rice fungal pathogens by diffusible and volatile compounds production. The strain was found positive for production of fungal cell wall degrading enzymes such as chitinase, β-1,3-glucanase, β-1,4-glucanase, lipase and protease. The strain was also positive for plant growth promoting traits. It produced up to 30.5μg/ml of IAA and solubilized a significant amount of inorganic phosphate (up to 102μg/ml). It also produced 69% siderophore units. The strain also produced ammonia and gave positive result for ACC deaminase activity. Highest vigor index of inoculated seedlings was observed when rice seeds were treated with cell suspension of UCR3-16 corresponding to 4.5×10(8)cfu/ml. Bioinoculant-treated seeds also showed similar results under pathogen challenged conditions. In pot trial experiments, UCR3-16-treated rice plants showed significantly increased growth and grain yield production. Powder formulation of the strain was developed using talcum and corn starch as carriers and the shelf-lives were monitored. Talcum formulation showed higher cell-count than corn starch even after 6 months of storage, and optimum condition for storage of the powder formulation were found to be at 4°C. Pot trial experiments using talcum powder formulation also showed significant positive effects on growth of rice plants. Field trial using talcum powder formulation also exhibited significant enhancement in shoot length and weight of shoot and root, and total grain yield and weight of grains in rice plants. Talcum formulation also significantly reduced the sheath blight disease in rice leaves. Copyright © 2016. Published by Elsevier GmbH.

  15. The availabilities of arsenic and cadmium in rice paddy fields from a mining area: The role of soil extractable and plant silicon.

    PubMed

    Yu, Huan-Yun; Ding, Xiaodong; Li, Fangbai; Wang, Xiangqin; Zhang, Shirong; Yi, Jicai; Liu, Chuanping; Xu, Xianghua; Wang, Qi

    2016-08-01

    Adequate silicon (Si) can greatly boost rice yield and improve grain quality through alleviating stresses associated with heavy metals and metalloids such as arsenic (As) and cadmium (Cd). The soil plant-available Si is relatively low in South China due to severe desilicification and allitization of the soils in this region. Conversely, pollution of heavy metals and metalloids in the soils of this region occurs widely, especially As and Cd pollution in paddy soil. Therefore, evaluating the plant availability of Si in paddy soil of South China and examining its correlation with the availability of heavy metals and metalloids are of great significance. Accordingly, in our study, 107 pairs of soil and rice plant samples were collected from paddy fields contaminated by As and Cd in South China. Significantly positive correlations between Si in rice plants and Si fractions in soils extracted with citric acid, NaOAc-HOAc buffer, and oxalate-ammonium oxalate buffer suggest that these extractants are more suitable for use in extracting plant-available Si in the soils of our present study. Significantly negative correlations between different Si fractions and As or Cd in rice plant tissues and negative exponential correlations between the molar ratios of Si to As/Cd in rice roots, straws, husks or grains and As/Cd in rice grains indicate that Si can significantly alleviate the accumulation of As/Cd from soils to the rice plants. Finally, a contribution assessment of soil properties to As/Cd accumulation in rice grains based on random forest showed that in addition to Si concentrations in soil or rice plants, other factors such as Fe fractions and total phosphorus also contributed largely to As/Cd accumulation in rice grains. Overall, Si exhibited its unique role in mitigating As or Cd stress in rice, and our study results provide strong field evidence for this role.

  16. Ascorbate biosynthesis and its involvement in stress tolerance and plant development in rice (Oryza sativa L.).

    PubMed

    Höller, Stefanie; Ueda, Yoshiaki; Wu, Linbo; Wang, Yunxia; Hajirezaei, Mohammad-Reza; Ghaffari, Mohammad-Reza; von Wirén, Nicolaus; Frei, Michael

    2015-08-01

    Ascorbic acid (AsA) biosynthesis and its implications for stress tolerance and plant development were investigated in a set of rice knock-out (KO) mutants for AsA biosynthetic genes and their wild-types. KO of two isoforms of GDP-D-mannose epimerase (OsGME) reduced the foliar AsA level by 20-30%, and KO of GDP-L-galactose phosphorylase (OsGGP) by 80%, while KO of myo-inositol oxygenase (OsMIOX) did not affect foliar AsA levels. AsA concentration was negatively correlated with lipid peroxidation in foliar tissue under ozone stress and zinc deficiency, but did not affect the sensitivity to iron toxicity. Lack of AsA reduced the photosynthetic efficiency as represented by the maximum carboxylation rate of Rubisco (Vmax), the maximum electron transport rate (Jmax) and the chlorophyll fluorescence parameter ΦPSII. Mutants showed lower biomass production than their wild-types, especially when OsGGP was lacking (around 80% reductions). All plants except for KO mutants of OsGGP showed distinct peaks in foliar AsA concentrations during the growth, which were consistent with up-regulation of OsGGP, suggesting that OsGGP plays a pivotal role in regulating foliar AsA levels during different growth stages. In conclusion, our data demonstrate multiple roles of AsA in stress tolerance and development of rice.

  17. The rice YABBY4 gene regulates plant growth and development through modulating the gibberellin pathway.

    PubMed

    Yang, Chao; Ma, Yamei; Li, Jianxiong

    2016-10-01

    YABBY genes encode seed plant-specific transcription factors that play pivotal roles in diverse aspects of leaf, shoot, and flower development. Members of the YABBY gene family are primarily expressed in lateral organs in a polar manner and function to specify abaxial cell fate in dicotyledons, but this polar expression is not conserved in monocotyledons. The function of YABBY genes is therefore not well understood in monocotyledons. Here we show that overexpression of the rice (Oryza sativa L.) YABBY4 gene (OsYABBY4) leads to a semi-dwarf phenotype, abnormal development in the uppermost internode, an increased number of floral organs, and insensitivity to gibberellin (GA) treatment. We report on an important role for OsYABBY4 in negative control of the expression of a GA biosynthetic gene by binding to the promoter region of the gibberellin 20-oxidase 2 gene (GA20ox2), which is a direct target of SLR1 (the sole DELLA protein negatively controlling GA responses in rice). OsYABBY4 also suppresses the expression level of SLR1 and interacts with SLR1 protein. The interaction inhibits GA-dependent degradation of SLR1 and therefore leads to GA insensitivity. These data together suggest that OsYABBY4 serves as a DNA-binding intermediate protein for SLR1 and is associated with the GA signaling pathway regulating gene expression during plant growth and development.

  18. Fast method for the simultaneous determination of monomethylmercury and inorganic mercury in rice and aquatic plants.

    PubMed

    Jiménez-Moreno, María; Lominchar, Miguel Ángel; Sierra, María José; Millán, Rocío; Martín-Doimeadios, Rosa Carmen Rodríguez

    2018-01-01

    Recent investigations revealed that monomethylmercury (MMHg) can be absorbed and accumulated by plants, i.e. rice crops, thus becoming an important route of human exposure to MMHg through diet. The increasing concern about this fact makes that appropriate analytical methods for Hg speciation in these samples are urgently required. Therefore, the aim of this work has been the development of a fast and sensitive method which enables the simultaneous determination of MMHg and inorganic Hg in rice and aquatic plants. The proposed methodology is based on the extraction of Hg species by closed-vessel microwave heating, subsequent derivatization by ethylation and analysis by gas chromatography coupled to atomic fluorescence detection via pyrolysis (GC-pyro-AFS). A careful optimization of the extraction, using both acid (6N HNO3) and alkaline (tetramethylammonium hydroxide, TMAH) extractants, and derivatization conditions has been carried out. Spiked and unspiked aquatic plants (Typha domingensis) and CRMs certified for Total-Hg (BCR-60, BCR-482 and NCS ZC73027, corresponding to aquatic plant, lichen and rice, respectively) have been used. Under the final optimized conditions the simultaneous determination of MMHg and inorganic Hg can be carried out in less than 40min with no tedious clean-up steps. Quantitative recoveries (from 92% to 101%) were obtained in aquatic plants (Typha domingensis) and CRMs spiked with known concentrations of MMHg. For unspiked BCR-60 and BCR-482, no statistically significant differences (p=0.05) were found in Total-Hg concentrations between those obtained by the sum of species and the certified values for both acid and alkaline extraction. For the analysis of low Hg polluted samples, an additional preconcentration step by evaporation under nitrogen stream was required but adequate blanks were only obtained for acid extraction. Detection limits in the low ng/g range (0.7-1.0ng/g) were consequently achieved for both Hg species in the case of acid

  19. Risk assessment and vertical distribution of thallium in paddy soils and uptake in rice plants irrigated with acid mine drainage.

    PubMed

    Huang, Xuexia; Li, Ning; Wu, Qihang; Long, Jianyou; Luo, Dinggui; Zhang, Ping; Yao, Yan; Huang, Xiaowu; Li, Dongmei; Lu, Yayin; Liang, Jianfeng

    2016-12-01

    The objective of this paper is to assess the influence of irritating paddy fields with acid mine drainage containing thallium (Tl) to rice plant-soil system and potential health risks for local residents. Vertical distribution of Tl, pH, organic matter (OM), and cation exchange capacity (CEC) in 24 paddy soil profiles around Yunfu pyrite mine area was investigated. Rice plant samples were collected from the corresponding soil sampling site. The results showed that Tl concentrations in paddy soils at 0-60 cm depth range from 3.07 to 9.42 mg kg(-1), with a mean of 5.74 mg kg(-1), which were significantly higher than the background value of soil in China (0.58 mg kg(-1)). On the whole, Tl contents in paddy soil profiles increased quickly with soil depth from 0 to 30 cm and decreased slowly with soil depth from 30 to 60 cm. The soil Tl content was significant negatively correlated with soil pH. The mean content of Tl in the root, stem, leaf, and rice was 4.36, 1.83, 2.74, and 1.42 mg kg(-1), respectively, which exceeded the proposed permissible limits for foods and feedstuffs in Germany. The Tl content in various tissues of the rice plants followed the order root > leaf > stem (rice), which suggested that most Tl taken up by rice plants retained in the root, and a little migrated to the leaf, stem, and rice. Correlation analysis showed that Tl content in root was significant positively correlated with Tl content in leaf and rice. The ranges of hazard quotient (HQ) values were 4.08∼24.50 and 3.84∼22.38 for males and females, respectively. Males have higher health risk than females in the same age group. In childhood age groups (2 to <21 years) and adult age groups (21 to <70 years), the highest health risk level was observed in the 11 to 16 age group and 21 to 50 age group, respectively. The findings indicated that regular irrigation with Tl-bearing acid mine drainage led to considerable contamination of Tl in paddy soil and rice plant. Local government

  20. 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.

  1. 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

  2. Chloroplast overexpression of rice caffeic acid O-methyltransferase increases melatonin production in chloroplasts via the 5-methoxytryptamine pathway in transgenic rice plants.

    PubMed

    Choi, Geun-Hee; Lee, Hyoung Yool; Back, Kyoungwhan

    2017-08-01

    Recent analyses of the enzymatic features of various melatonin biosynthetic genes from bacteria, animals, and plants have led to the hypothesis that melatonin could be synthesized via the 5-methoxytryptamine (5-MT) pathway. 5-MT is known to be synthesized in vitro from serotonin by the enzymatic action of O-methyltransferases, including N-acetylserotonin methyltransferase (ASMT) and caffeic acid O-methyltransferase (COMT), leading to melatonin synthesis by the subsequent enzymatic reaction with serotonin N-acetyltransferase (SNAT). Here, we show that 5-MT was produced and served as a precursor for melatonin synthesis in plants. When rice seedlings were challenged with senescence treatment, 5-MT levels and melatonin production were increased in transgenic rice seedlings overexpressing the rice COMT in chloroplasts, while no such increases were observed in wild-type or transgenic seedlings overexpressing the rice COMT in the cytosol, suggesting a 5-MT transport limitation from the cytosol to chloroplasts. In contrast, cadmium treatment led to results different from those in senescence. The enhanced melatonin production was not observed in the chloroplast COMT lines relative over the cytosol COMT lines although 5-MT levels were equally induced in all genotypes upon cadmium treatment. The transgenic seedlings with enhanced melatonin in their chloroplasts exhibited improved seedling growth vs the wild type under continuous light conditions. This is the first report describing enhanced melatonin production in chloroplasts via the 5-MT pathway with the ectopic overexpression of COMT in chloroplasts in plants. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. 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.

  4. Plant Gene and Alternatively Spliced Variant Annotator. A plant genome annotation pipeline for rice gene and alternatively spliced variant identification with cross-species expressed sequence tag conservation from seven plant species.

    PubMed

    Chen, Feng-Chi; Wang, Sheng-Shun; Chaw, Shu-Miaw; Huang, Yao-Ting; Chuang, Trees-Juen

    2007-03-01

    The completion of the rice (Oryza sativa) genome draft has brought unprecedented opportunities for genomic studies of the world's most important food crop. Previous rice gene annotations have relied mainly on ab initio methods, which usually yield a high rate of false-positive predictions and give only limited information regarding alternative splicing in rice genes. Comparative approaches based on expressed sequence tags (ESTs) can compensate for the drawbacks of ab initio methods because they can simultaneously identify experimental data-supported genes and alternatively spliced transcripts. Furthermore, cross-species EST information can be used to not only offset the insufficiency of same-species ESTs but also derive evolutionary implications. In this study, we used ESTs from seven plant species, rice, wheat (Triticum aestivum), maize (Zea mays), barley (Hordeum vulgare), sorghum (Sorghum bicolor), soybean (Glycine max), and Arabidopsis (Arabidopsis thaliana), to annotate the rice genome. We developed a plant genome annotation pipeline, Plant Gene and Alternatively Spliced Variant Annotator (PGAA). Using this approach, we identified 852 genes (931 isoforms) not annotated in other widely used databases (i.e. the Institute for Genomic Research, National Center for Biotechnology Information, and Rice Annotation Project) and found 87% of them supported by both rice and nonrice EST evidence. PGAA also identified more than 44,000 alternatively spliced events, of which approximately 20% are not observed in the other three annotations. These novel annotations represent rich opportunities for rice genome research, because the functions of most of our annotated genes are currently unknown. Also, in the PGAA annotation, the isoforms with non-rice-EST-supported exons are significantly enriched in transporter activity but significantly underrepresented in transcription regulator activity. We have also identified potential lineage-specific and conserved isoforms, which are

  5. Disease incidence and severity of rice plants in conventional chemical fertilizer input compared with organic farming systems

    NASA Astrophysics Data System (ADS)

    Hu, Xue-Feng; Luo, Fan

    2015-04-01

    To study the impacts of different fertilizer applications on rice growth and disease infection, a 3-year field experiment of rice cultivation was carried out in the suburb of Shanghai from 2012-2014. No any pesticides and herbicides were applied during the entire experiment to prevent their disturbance to rice disease. Compared with green (GM) and cake manures (CM), the application of chemical fertilizer (CF) stimulated the photosysthesis and vegetative growth of rice plants more effectively. Chlorophyll content, height and tiller number of the rice plants treated with the CF were generally higher than those treated with the GM and CM and the control; the contents of nitrate (NO3--N), ammonium (NH4+-N), Kjeldahl nitrogen (KN) and soluble protein treated with the CF were also higher than those with the others during the 3-year experiment. The 3-year experiment also indicated that the incidences of stem borers, shreath blight, leaf rollers and planthoppers of the rice treated with the CF were signficantly higher than those treated with the GM and CM and the control. Especially in 2012 and 2014, the incidences of rice pests and diseases treated with the CF were far more severe than those with the others. As a result, the grain yield treated with the CF was not only lower than that treated with the GM and CM, but also lower than that of the no-fertilizer control. This might be attributed to two reasons: Pests favor the rice seedlings with sufficient N-related nutrients caused by CF application; the excessive accumulation of nutrients in the seedlings might have toxic effects and weaken their immune systems, thus making them more vulnerable to pests and diseases. In comparison, the plants treated with a suitable amount of organic manure showed a better capability of disease resistance and grew more healthy. In addition, the incidences of rice pests and diseases might also be related to climatic conditions. Shanghai was hit by strong subtropical storms in the summer of

  6. Increased Fitness of Rice Plants to Abiotic Stress Via Habitat Adapted Symbiosis: A Strategy for Mitigating Impacts of Climate Change

    PubMed Central

    Redman, Regina S.; Kim, Yong Ok; Woodward, Claire J. D. A.; Greer, Chris; Espino, Luis; Doty, Sharon L.; Rodriguez, Rusty J.

    2011-01-01

    Climate change and catastrophic events have contributed to rice shortages in several regions due to decreased water availability and soil salinization. Although not adapted to salt or drought stress, two commercial rice varieties achieved tolerance to these stresses by colonizing them with Class 2 fungal endophytes isolated from plants growing across moisture and salinity gradients. Plant growth and development, water usage, ROS sensitivity and osmolytes were measured with and without stress under controlled conditions. The endophytes conferred salt, drought and cold tolerance to growth chamber and greenhouse grown plants. Endophytes reduced water consumption by 20–30% and increased growth rate, reproductive yield, and biomass of greenhouse grown plants. In the absence of stress, there was no apparent cost of the endophytes to plants, however, endophyte colonization decreased from 100% at planting to 65% compared to greenhouse plants grown under continual stress (maintained 100% colonization). These findings indicate that rice plants can exhibit enhanced stress tolerance via symbiosis with Class 2 endophytes, and suggest that symbiotic technology may be useful in mitigating impacts of climate change on other crops and expanding agricultural production onto marginal lands. PMID:21750695

  7. Increased fitness of rice plants to abiotic stress via habitat adapted symbiosis: A strategy for mitigating impacts of climate change

    USGS Publications Warehouse

    Redman, R.S.; Kim, Y.-O.; Woodward, C.J.D.A.; Greer, C.; Espino, L.; Doty, S.L.; Rodriguez, R.J.

    2011-01-01

    Climate change and catastrophic events have contributed to rice shortages in several regions due to decreased water availability and soil salinization. Although not adapted to salt or drought stress, two commercial rice varieties achieved tolerance to these stresses by colonizing them with Class 2 fungal endophytes isolated from plants growing across moisture and salinity gradients. Plant growth and development, water usage, ROS sensitivity and osmolytes were measured with and without stress under controlled conditions. The endophytes conferred salt, drought and cold tolerance to growth chamber and greenhouse grown plants. Endophytes reduced water consumption by 20–30% and increased growth rate, reproductive yield, and biomass of greenhouse grown plants. In the absence of stress, there was no apparent cost of the endophytes to plants, however, endophyte colonization decreased from 100% at planting to 65% compared to greenhouse plants grown under continual stress (maintained 100% colonization). These findings indicate that rice plants can exhibit enhanced stress tolerance via symbiosis with Class 2 endophytes, and suggest that symbiotic technology may be useful in mitigating impacts of climate change on other crops and expanding agricultural production onto marginal lands.

  8. Increased fitness of rice plants to abiotic stress via habitat adapted symbiosis: a strategy for mitigating impacts of climate change.

    PubMed

    Redman, Regina S; Kim, Yong Ok; Woodward, Claire J D A; Greer, Chris; Espino, Luis; Doty, Sharon L; Rodriguez, Rusty J

    2011-01-01

    Climate change and catastrophic events have contributed to rice shortages in several regions due to decreased water availability and soil salinization. Although not adapted to salt or drought stress, two commercial rice varieties achieved tolerance to these stresses by colonizing them with Class 2 fungal endophytes isolated from plants growing across moisture and salinity gradients.Plant growth and development, water usage, ROS sensitivity and osmolytes were measured with and without stress under controlled conditions.The endophytes conferred salt, drought and cold tolerance to growth chamber and greenhouse grown plants. Endophytes reduced water consumption by 20-30% and increased growth rate, reproductive yield, and biomass of greenhouse grown plants. In the absence of stress, there was no apparent cost of the endophytes to plants, however, endophyte colonization decreased from 100% at planting to 65% compared to greenhouse plants grown under continual stress (maintained 100% colonization).These findings indicate that rice plants can exhibit enhanced stress tolerance via symbiosis with Class 2 endophytes, and suggest that symbiotic technology may be useful in mitigating impacts of climate change on other crops and expanding agricultural production onto marginal lands.

  9. Metabolomic analysis of wild and transgenic Nicotiana langsdorffii plants exposed to abiotic stresses: unraveling metabolic responses.

    PubMed

    Scalabrin, Elisa; Radaelli, Marta; Rizzato, Giovanni; Bogani, Patrizia; Buiatti, Marcello; Gambaro, Andrea; Capodaglio, Gabriele

    2015-08-01

    Nicotiana langsdorffii plants, wild and transgenic for the Agrobacterium rhizogenes rol C gene and the rat glucocorticoid receptor (GR) gene, were exposed to different abiotic stresses (high temperature, water deficit, and high chromium concentrations). An untargeted metabolomic analysis was carried out in order to investigate the metabolic effects of the inserted genes in response to the applied stresses and to obtain a comprehensive profiling of metabolites induced during abiotic stresses. High-performance liquid chromatography separation (HPLC) coupled to high-resolution mass spectrometry (HRMS) enabled the identification of more than 200 metabolites, and statistical analysis highlighted the most relevant compounds for each plant treatment. The plants exposed to heat stress showed a unique set of induced secondary metabolites, some of which were known while others were not previously reported for this kind of stress; significant changes were observed especially in lipid composition. The role of trichome, as a protection against heat stress, is here suggested by the induction of both acylsugars and glykoalkaloids. Water deficit and Cr(VI) stresses resulted mainly in enhanced antioxidant (HCAs, polyamine) levels and in the damage of lipids, probably as a consequence of reactive oxygen species (ROS) production. Moreover, the ability of rol C expression to prevent oxidative burst was confirmed. The results highlighted a clear influence of GR modification on plant stress response, especially to water deficiency-a phenomenon whose applications should be further investigated. This study provides new insights into the field of system biology and demonstrates the importance of metabolomics in the study of plant functioning. Graphical Abstract Untargeted metabolomic analysis was applied to wild type, GR and RolC modified Nicotiana Langsdorffii plants exposed to heat, water and Cr(VI) stresses. The key metabolites, highly affected by stress application, were identified

  10. Post-surgical scalp wounds with exposed bone treated with a plant-derived wound therapeutic.

    PubMed

    Läuchli, S; Hafner, J; Wehrmann, C; French, L E; Hunziker, T

    2012-05-01

    To evaluate the efficacy of a plant-derived wound dressing, a mixture of hypericum oil (Hypericum perforatum) and neem oil (Azadirachta indica), in scalp wounds with exposed bone. A retrospective review was conducted of all patients presenting with scalp wounds with exposed bone following the excision of skin tumours and treated with a plant-derived wound dressings (1 Primary Wound Dressing; Phytoceuticals AG), from January to July 2011. Time to healing, wound size, area of exposed bone, ease of handling, pain and complications were evaluated. Nine consecutive patients were analysed retrospectively. The patients' mean age was 81.2 ± 8.5 years (63-90 years), with a mean wound size of 13.2 ± 6.8cm(2) (0.4-22.6cm(2)) and 6.8 ± 6.5cm(2) (0.3-20.7cm(2)) of exposed bone. The time to complete healing by secondary intention was 4-20 weeks. A rapid induction of granulation tissue was observed, which covered the entire exposed bone surface in six out of nine cases (67%) after 4 weeks, and showed a reduction in the mean area of exposed bone of 95%. Dressing change was easy and without pain and there were no complications. This retrospective, non-controlled analysis suggests that ONE is a very simple to use, safe and potentially effective therapy for the treatment of scalp wounds with exposed bone. There were no external sources of funding for this study. The authors have no conflict of interest to declare.

  11. Lipid peroxidation and antioxidant status in workers exposed to PCDD/Fs of metal recovery plants.

    PubMed

    Chen, Hsiu-Ling; Hsu, Ching-Yi; Hung, Dong-Zong; Hu, Miao-Lin

    2006-12-15

    Secondary copper smelters, which primarily utilize the waste materials that contain organic impurities, and the zinc recovery plant, which handles mostly fly ash and slag from the iron and steel industry, are major emission sources of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in Taiwan. In this study, we compared the levels of erythrocyte glutathione (GSH), erythrocyte superoxide dismutase (SOD) and plasma malondialdehyde (MDA) in workers at a secondary copper smelting plant and a zinc recovery plant who may have been exposed to PCDD/Fs. Though the PCDD/F levels were higher in workers of zinc recovery plant than those of secondary copper smelting plant, no significant difference was found for serum PCDD/F levels between the two kinds of plants. We observed a significant difference in plasma MDA levels between workers at the zinc recovery plant (2.54 microM) and those at the copper smelting plant (1.79 microM). There was and a significant positive correlation between plasma MDA levels and the PCDD/Fs levels. In addition, we observed that the MDA levels were not affected by smoking and exercise status. Therefore, the data suggest that the MDA levels of the metal recovery workers are influenced by their PCDD/F exposure. The erythrocyte SOD activity in workers from the zinc recovery plant was marginally higher than that from the secondary copper plant (196 vs. 146 units/ml, p<0.06). In both plants, large variations in the MDA and SOD levels were found, especially in the high-PCDD/Fs-exposure group, which may be attributed, at least partially, to the differences in smoking status and the number of cigarettes smoked. Overall, our results indicate a higher oxidative stress in workers of the zinc recovery plant than in workers of the secondary copper smelting plant in Taiwan.

  12. Expression of the maize proteinase inhibitor (mpi) gene in rice plants enhances resistance against the striped stem borer (Chilo suppressalis): effects on larval growth and insect gut proteinases.

    PubMed

    Vila, Laura; Quilis, Jordi; Meynard, Donaldo; Breitler, Jean Christophe; Marfà, Victoria; Murillo, Isabel; Vassal, Jean Michel; Messeguer, Joaquima; Guiderdoni, Emmanuel; San Segundo, Blanca

    2005-03-01

    The maize proteinase inhibitor (mpi) gene was introduced into two elite japonica rice varieties. Both constitutive expression of the mpi gene driven by the maize ubiquitin 1 promoter and wound-inducible expression of the mpi gene driven by its own promoter resulted in the accumulation of MPI protein in the transgenic plants. No effect on plant phenotype was observed in mpi-expressing lines. The stability of transgene expression through successive generations of mpi rice lines (up to the T(4) generation) and the production of functional MPI protein were confirmed. Expression of the mpi gene in rice enhanced resistance to the striped stem borer (Chilo suppressalis), one of the most important pests of rice. In addition, transgenic mpi plants were evaluated in terms of their effects on the growth of C. suppressalis larvae and the insect digestive proteolytic system. An important dose-dependent reduction of larval weight of C. suppressalis larvae fed on mpi rice, compared with larvae fed on untransformed rice plants, was observed. Analysis of the digestive proteolytic activity from the gut of C. suppressalis demonstrated that larvae adapted to mpi transgene expression by increasing the complement of digestive proteolytic activity: the serine and cysteine endoproteinases as well as the exopeptidases leucine aminopeptidase and carboxypeptidases A and B. However, the induction of such proteolytic activity did not prevent the deleterious effects of MPI on larval growth. The introduction of the mpi gene into rice plants can thus be considered as a promising strategy to protect rice plants against striped stem borer.

  13. Defence responses in rice plants in prior and simultaneous applications of Cladosporium sp. during leaf blast suppression.

    PubMed

    Chaibub, Amanda Abdallah; de Carvalho, Jacqueline Campos Borba; de Sousa Silva, Carlos; Collevatti, Rosane Garcia; Gonçalves, Fábio José; de Carvalho Barros Côrtes, Márcio Vinícius; de Filippi, Marta Cristina Corsi; de Faria, Fabrícia Paula; Lopes, Douglas Christian Borges; de Araújo, Leila Garcês

    2016-11-01

    An alternative method to control rice blast (Magnaporthe oryzae) is to include biological agent in the disease management strategy. The objective of this study was to assess the leaf blast-suppressing effects of rice phylloplane fungi. One Cladosporium sp. phylloplane fungus was shown to possess biocontrolling traits based on its morphological characteristics and an analysis of its 18S ribosomal DNA. Experiments aimed at determining the optimal time to apply the bioagent and the mechanisms involved in its rice blast-suppressing activities were performed under controlled greenhouse conditions. We used foliar spraying to apply the Cladosporium sp. 48 h prior to applying the pathogen, and we found that this increased the enzymatic activity. Furthermore, in vitro tests performed using isolate C24 showed that it possessed the ability to secrete endoxylanases and endoglucanases. When Cladosporium sp. was applied either prior to or simultaneous with the pathogen, we observed a significant increase in defence enzyme activity, and rice blast was suppressed by 84.0 and 78.6 %, respectively. However, some enzymes showed higher activity at 24 h while others did so at 48 h after the challenge inoculation. Cladosporium sp. is a biological agent that is capable of suppressing rice leaf blast by activating biochemical defence mechanisms in rice plants. It is highly adapted to natural field conditions and should be included in further studies aimed at developing strategies to support ecologically sustainable disease management and reduce environmental pollution by the judicious use of fungicidal sprays.

  14. Rice Morphogenesis and Plant Architecture: Measurement, Specification and the Reconstruction of Structural Development by 3D Architectural Modelling

    PubMed Central

    WATANABE, TOMONARI; HANAN, JIM S.; ROOM, PETER M.; HASEGAWA, TOSHIHIRO; NAKAGAWA, HIROSHI; TAKAHASHI, WATARU

    2005-01-01

    • Background and Aims The morphogenesis and architecture of a rice plant, Oryza sativa, are critical factors in the yield equation, but they are not well studied because of the lack of appropriate tools for 3D measurement. The architecture of rice plants is characterized by a large number of tillers and leaves. The aims of this study were to specify rice plant architecture and to find appropriate functions to represent the 3D growth across all growth stages. • Methods A japonica type rice, ‘Namaga’, was grown in pots under outdoor conditions. A 3D digitizer was used to measure the rice plant structure at intervals from the young seedling stage to maturity. The L-system formalism was applied to create ‘3D virtual rice’ plants, incorporating models of phenological development and leaf emergence period as a function of temperature and photoperiod, which were used to determine the timing of tiller emergence. • Key Results The relationships between the nodal positions and leaf lengths, leaf angles and tiller angles were analysed and used to determine growth functions for the models. The ‘3D virtual rice’ reproduces the structural development of isolated plants and provides a good estimation of the tillering process, and of the accumulation of leaves. • Conclusions The results indicated that the ‘3D virtual rice’ has a possibility to demonstrate the differences in the structure and development between cultivars and under different environmental conditions. Future work, necessary to reflect both cultivar and environmental effects on the model performance, and to link with physiological models, is proposed in the discussion. PMID:15820987

  15. Bacillus oryzicola sp. nov., an Endophytic Bacterium Isolated from the Roots of Rice with Antimicrobial, Plant Growth Promoting, and Systemic Resistance Inducing Activities in Rice

    PubMed Central

    Chung, Eu Jin; Hossain, Mohammad Tofajjal; Khan, Ajmal; Kim, Kyung Hyun; Jeon, Che Ok; Chung, Young Ryun

    2015-01-01

    Biological control of major rice diseases has been attempted in several rice-growing countries in Asia during the last few decades and its application using antagonistic bacteria has proved to be somewhat successful for controlling various fungal diseases in field trials. Two novel endophytic Bacillus species, designated strains YC7007 and YC7010T, with anti-microbial, plant growth-promoting, and systemic resistance-inducing activities were isolated from the roots of rice in paddy fields at Jinju, Korea, and their multifunctional activities were analyzed. Strain YC7007 inhibited mycelial growth of major rice fungal pathogens strongly in vitro. Bacterial blight and panicle blight caused by Xanthomonas oryzae pv. oryzae (KACC 10208) and Burkholderia glumae (KACC 44022), respectively, were also suppressed effectively by drenching a bacterial suspension (107 cfu/ml) of strain YC7007 on the rhizosphere of rice. Additionally, strain YC7007 promoted the growth of rice seedlings with higher germination rates and more tillers than the untreated control. The taxonomic position of the strains was also investigated. Phylogenetic analyses based on 16S rRNA gene sequences indicated that both strains belong to the genus Bacillus, with high similarity to the closely related strains, Bacillus siamensis KACC 15859T (99.67%), Bacillus methylotrophicus KACC 13105T (99.65%), Bacillus amyloliquefaciens subsp. plantarum KACC 17177T (99.60%), and Bacillus tequilensis KACC 15944T (99.45%). The DNA-DNA relatedness value between strain YC7010T and the most closely related strain, B. siamensis KACC 15859T was 50.4±3.5%, but it was 91.5±11.0% between two strains YC7007 and YC7010T, indicating the same species. The major fatty acids of two strains were anteiso-C15:0 and iso C15:0. Both strains contained MK-7 as a major respiratory quinone system. The G+C contents of the genomic DNA of two strains were 50.5 mol% and 51.2 mol%, respectively. Based on these polyphasic studies, the two strains YC

  16. Metaproteomic Identification of Diazotrophic Methanotrophs and Their Localization in Root Tissues of Field-Grown Rice Plants

    PubMed Central

    Bao, Zhihua; Okubo, Takashi; Kubota, Kengo; Kasahara, Yasuhiro; Tsurumaru, Hirohito; Anda, Mizue; Ikeda, Seishi

    2014-01-01

    In a previous study by our group, CH4 oxidation and N2 fixation were simultaneously activated in the roots of wild-type rice plants in a paddy field with no N input; both processes are likely controlled by a rice gene for microbial symbiosis. The present study examined which microorganisms in rice roots were responsible for CH4 oxidation and N2 fixation under the field conditions. Metaproteomic analysis of root-associated bacteria from field-grown rice (Oryza sativa Nipponbare) revealed that nitrogenase complex-containing nitrogenase reductase (NifH) and the alpha subunit (NifD) and beta subunit (NifK) of dinitrogenase were mainly derived from type II methanotrophic bacteria of the family Methylocystaceae, including Methylosinus spp. Minor nitrogenase proteins such as Methylocella, Bradyrhizobium, Rhodopseudomonas, and Anaeromyxobacter were also detected. Methane monooxygenase proteins (PmoCBA and MmoXYZCBG) were detected in the same bacterial group of the Methylocystaceae. Because these results indicated that Methylocystaceae members mediate both CH4 oxidation and N2 fixation, we examined their localization in rice tissues by using catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH). The methanotrophs were localized around the epidermal cells and vascular cylinder in the root tissues of the field-grown rice plants. Our metaproteomics and CARD-FISH results suggest that CH4 oxidation and N2 fixation are performed mainly by type II methanotrophs of the Methylocystaceae, including Methylosinus spp., inhabiting the vascular bundles and epidermal cells of rice roots. PMID:24928870

  17. Exogenously Applied Plant Growth Regulators Enhance the Morpho-Physiological Growth and Yield of Rice under High Temperature

    PubMed Central

    Fahad, Shah; Hussain, Saddam; Saud, Shah; Hassan, Shah; Ihsan, Zahid; Shah, Adnan N.; Wu, Chao; Yousaf, Muhammad; Nasim, Wajid; Alharby, Hesham; Alghabari, Fahad; Huang, Jianliang

    2016-01-01

    A 2-year experiment was conducted to ascertain the effects of exogenously applied plant growth regulators (PGR) on rice growth and yield attributes under high day (HDT) and high night temperature (HNT). Two rice cultivars (IR-64 and Huanghuazhan) were subjected to temperature treatments in controlled growth chambers and four different combinations of ascorbic acid (Vc), alpha-tocopherol (Ve), brassinosteroids (Br), methyl jasmonates (MeJA), and triazoles (Tr) were applied. High temperature severely affected rice morphology, and also reduced leaf area, above-, and below-ground biomass, photosynthesis, and water use efficiency, while increased the leaf water potential of both rice cultivars. Grain yield and its related attributes except number of panicles, were reduced under high temperature. The HDT posed more negative effects on rice physiological attributes, while HNT was more detrimental for grain formation and yield. The Huanghuazhan performed better than IR-64 under high temperature stress with better growth and higher grain yield. Exogenous application of PGRs was helpful in alleviating the adverse effects of high temperature. Among PGR combinations, the Vc+Ve+MejA+Br was the most effective treatment for both cultivars under high temperature stress. The highest grain production by Vc+Ve+MejA+Br treated plants was due to enhanced photosynthesis, spikelet fertility and grain filling, which compensated the adversities of high temperature stress. Taken together, these results will be of worth for further understanding the adaptation and survival mechanisms of rice to high temperature and will assist in developing heat-resistant rice germplasm in future. PMID:27625658

  18. Arabidopsis plants exposed to gamma radiation in two successive generations show a different oxidative stress response.

    PubMed

    van de Walle, Jorden; Horemans, Nele; Saenen, Eline; Van Hees, May; Wannijn, Jean; Nauts, Robin; van Gompel, Axel; Vangronsveld, Jaco; Vandenhove, Hildegarde; Cuypers, Ann

    2016-12-01

    When terrestrial environments get contaminated with long-lived gamma emitting radionuclides, plants that grow in these contaminated areas are exposed to gamma radiation during consecutive generations. Therefore it is important to evaluate the gamma induced stress response in plants in and between generations. The objective of this research is to reveal differences at the level of the antioxidative stress response between generations with a different radiation history. An experiment was conducted in which 7-days old Arabidopsis thaliana plants were exposed for 14 days to four different gamma dose rates: 22 mGy/h, 38 mGy/h, 86 mGy/h and 457 mGy/h. Two different plant groups were used: plants that were not exposed to gamma radiation before (P0) and plants that received the aforementioned gamma treatment during their previous generation (S1). Growth, the concentration of the antioxidants ascorbate and glutathione, a number of antioxidative enzyme activities and their gene transcript levels were analysed. A dose-rate dependent induction was seen for catalase (CAT) and guaiacol peroxidase (GPX) in the roots and for syringaldazine peroxidase (SPX) in the shoots. Differences between the two generations were observed for CAT and GPX in the roots, where a significantly higher activity of these reactive oxygen species (ROS) detoxifying enzymes was observed in the S1 generation. For SPX in the shoots, a dose dependent upregulation was observed in the P0 generation. However, high SPX activities were present for all doses in the S1 generation. These differences in enzyme activity between generations for SPX and GPX and the involvement of these enzymes in cell wall biosynthesis, suggest an important role for cell wall strengthening in the response to gamma irradiation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Cytokinin response in pepper plants (Capsicum annuum L.) exposed to silver nanoparticles.

    PubMed

    Vinković, Tomislav; Novák, Ondrej; Strnad, Miroslav; Goessler, Walter; Jurašin, Darija Domazet; Parađiković, Nada; Vrček, Ivana Vinković

    2017-07-01

    The increasing development of different nanomaterials, such as silver nanoparticles (AgNPs), and their practical use in agriculture and biotechnology has created a strong need for elucidations of biological effects and risk assessments of AgNPs in plants. This study was aimed to investigate AgNPs effects on metal uptake and their biodistribution in pepper plants as well as on morphological parameters and hormonal responses of the isoprenoid cytokinin (CK) family. In addition, the comparison of effects silver form, nanoparticles vs. ionic, has also been examined. To the best of our knowledge, this is the first study describing CK responses in plants exposed to metallic NPs. The obtained results indicate that both AgNPs and Ag(+) ions significantly increased total content of Ag(+) in pepper tissues in a dose-dependent manner and affected on plant development by decreasing both plant height and biomass in a similar way. This study evidenced for the first time the role of CKs in abiotic stress in plants caused by AgNPs. The hormonal analysis, conducted by an ultra-high performance liquid chromatography-electrospray tandem mass spectrometry, revealed a significant increase in total CKs in the leaves and also highlighted the importance of cis-zeatin type CKs in plants treated with AgNPs. Our observations suggest potential risks of AgNPs on plant ecosystems upon their release into the environment. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Effect of planting date on Lissorhoptrus oryzophilus (Coleoptera: Curculionidae) density-yield relationship on rice in southeastern Texas.

    PubMed

    Espino, L; Way, M O; Pearson, R; Nunez, M

    2009-08-01

    Results of planting date and insecticide efficacy experiments targeting Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae) on rice, Oryza sativa L., in southeastern Texas between 2002 and 2007 were used to determine density-yield relationships as a function of planting date. Soil core samples were collected on two dates during main crop development to estimate immature L. oryzophilus populations followed by main and ratoon crop harvests. Analysis of covariance (ANCOVA) revealed that planting date did not affect the density-main crop yield relationship during most years and that these relationships varied substantially among years. For ratoon crop yield, an effect of main crop L. oryzophilus immature infestation was detected during some years, but the real effect of these populations on ratoon crop yield remains unclear. Using estimates of yield reduction per L. oryzophilus immature, economic injury levels were calculated. Main crop yields from treated plots and first soil core sample L. oryzophilus immature populations from untreated plots were significantly higher in plots planted at recommended dates than in plots planted earlier or later. This suggests that the presence of high populations of reproductive L. oryzophilus coincides with the period when rice fields planted at optimum dates are flooded. Results from this study reinforce the importance of managing L. oryzophilus populations when planting rice at recommended dates in southeastern Texas.

  1. Roles of plant hormones and anti-apoptosis genes during drought stress in rice (Oryza sativa L.).

    PubMed

    Ubaidillah, Mohammad; Safitri, Fika Ayu; Jo, Jun-Hyeon; Lee, Sang-Kyu; Hussain, Adil; Mun, Bong-Gyu; Chung, Il Kyung; Yun, Byung-Wook; Kim, Kyung-Min

    2016-12-01

    We previously identified the rice (Oryza sativa) senescence-associated gene OsSAP which encodes a highly conserved protein involved in anti-apoptotic activity. This novel Bax suppressor-related gene regulates tolerance to multiple stresses in yeast. Here, we show the effects of drought stress on leaf and root tissues of plants over-expressing OsSAP in relation to the levels of phytohormones, abscisic acid (ABA), jasmonic acid (JA), indole-3-carboxylic acid (ICA), gibberellic acid (GA3), and zeatin. Results showed that rice plants over-expressing SAP were tolerant to drought stress compared to wild type and the plants over-expressing AtBI-1, which is a homolog of the human Bax inhibitor-1 in Arabidopsis. ABA and JA levels in OsSAP and AtBI-1 transgenic plants consistently increased up to at least 3 days after drought treatment, whereas lower GA3 levels were recorded during early drought period. Comparison between control and transgenic plants overexpressing anti-apoptosis genes OsSAP and AtBI-1 resulted in different patterns of hormone levels, indicating that these genes are involved in the plant responses to drought stress and present an opportunity for further study on drought stress tolerance in rice and other plant species.

  2. Impacts of rapeseed dregs on Cd availability in contaminated acid soil and Cd translocation and accumulation in rice plants.

    PubMed

    Yang, Wen-Tao; Gu, Jiao-Feng; Zou, Jia-Ling; Zhou, Hang; Zeng, Qing-Ru; Liao, Bo-Han

    2016-10-01

    The objective of the present study was to investigate the effects of rapeseed dregs (RSD, a commonly organic fertilizer in rural China) at application rates of 0, 0.75, 1.5, and 3.0 % on Cd availability in soil and its accumulation in rice plants (Oryza sativa L., Xiangwanxian 12(#), and Weiyou 46(#)) by means of a pot experiment. The results showed that application of RSD resulted in a sharp decrease in the soil TCLP-extractable Cd content. However, the soil TCLP-extractable Cd content in amended soil gradually increased during the rice growing period. Application of RSD significantly increased Cd transport from root to shoot and the amount of Cd accumulated in the aerial part. RSD was an effective organic additive for increasing rice grain yield, but total Cd content in rice grain was also increased. At an application rate of 1.5-3.0 % RSD, the total Cd content in Weiyou 46(#) brown rice was 0.27-0.31 mg kg(-1), which exceeded the standard safe limit (0.2 mg kg(-1)) and was also higher than that of Xiangwanxian 12(#) (0.04-0.14 mg kg(-1)). Therefore, Weiyou 46(#) had a higher dietary risk than Xiangwanxian 12(#) with RSD application. We do not recommend planting Weiyou 46(#) and applying more than 0.75 % RSD in Cd-contaminated paddy fields.

  3. Biomass, gas exchange, and nutrient contents in upland rice plants affected by application forms of microorganism growth promoters.

    PubMed

    Nascente, Adriano Stephan; de Filippi, Marta Cristina Corsi; Lanna, Anna Cristina; de Souza, Alan Carlos Alves; da Silva Lobo, Valácia Lemes; da Silva, Gisele Barata

    2017-01-01

    Microorganisms are considered a genetic resource with great potential for achieving sustainable development of agricultural areas. The objective of this research was to determine the effect of microorganism application forms on the production of biomass, gas exchange, and nutrient content in upland rice. The experiment was conducted under greenhouse conditions in a completely randomized design in a factorial 7 × 3 + 1, with four replications. The treatments consisted of combining seven microorganisms with three application forms (microbiolized seed; microbiolized seed + soil drenched with a microorganism suspension at 7 and 15 days after sowing (DAS); and microbiolized seed + plant sprayed with a microorganism suspension at 7 and 15 DAS) and a control (water). Treatments with Serratia sp. (BRM32114), Bacillus sp. (BRM32110 and BRM32109), and Trichoderma asperellum pool provided, on average, the highest photosynthetic rate values and dry matter biomass of rice shoots. Plants treated with Burkolderia sp. (BRM32113), Serratia sp. (BRM32114), and Pseudomonas sp. (BRM32111 and BRM32112) led to the greatest nutrient uptake by rice shoots. Serratia sp. (BRM 32114) was the most effective for promoting an increase in the photosynthetic rate, and for the greatest accumulation of nutrients and dry matter at 84 DAS, in rice shoots, which differed from the control treatment. The use of microorganisms can bring numerous benefits of rice, such as improving physiological characteristics, nutrient uptake, biomass production, and grain yield.

  4. Phase Identification and Internal Stress Analysis of Steamside Oxides on Plant Exposed Superheater Tubes

    NASA Astrophysics Data System (ADS)

    Pantleon, Karen; Montgomery, Melanie

    2012-05-01

    During long-term, high-temperature exposure of superheater tubes in thermal power plants, various oxides are formed on the inner side (steamside) of the tubes, and oxide spallation is a serious problem for the power plant industry. Most often, oxidation in a steam atmosphere is investigated in laboratory experiments just mimicking the actual conditions in the power plant for simplified samples. On real plant-exposed superheater tubes, the steamside oxides are solely investigated microscopically. The feasibility of X-ray diffraction for the characterization of steamside oxidation on real plant-exposed superheater tubes was proven in the current work; the challenges for depth-resolved phase analysis and phase-specific residual stress analysis at the inner side of the tubes with concave surface curvature are discussed. Essential differences between the steamside oxides formed on two different steels typically applied for superheaters, ferritic-martensitic X20CrMoV12-1 and lean austenitic stainless steel TP347H, respectively, are revealed by X-ray diffraction.

  5. Pigmented Rice Bran and Plant Sterol Combination Reduces Serum Lipids in Overweight and Obese Adults

    PubMed Central

    Hongu, Nobuko; Kitts, David D.; Zawistowski, Jerzy; Dossett, Cynthia M.; Kopeć, Aneta; Pope, Benjamin T.; Buchowski, Maciej S.

    2015-01-01

    Objective This study investigated the dietary effect of including pigmented rice bran with or without plant sterols on lipid profiles during energy restriction–induced weight loss in overweight and obese adults not taking cholesterol-lowering medication. In addition, the study examined the effect of intervention on biomarkers of oxidative stress and inflammation. Methods A group of 24 overweight and obese adults (age: 43 ± 6 years, body mass index 32 ± 1 kg/m2, 18 females) were randomized to a 25% calorie-restricted diet containing either pigmented rice bran (RB) or the RB with addition of plant sterols (RB + PS) snack bars for 8 weeks. The individualized nutrient-balanced diet contained ~70% of daily energy needs assessed from indirect calorimetry measured resting energy expenditure (EE) and physical activity-related EE assessed using accelerometry. Anthropometrics, blood pressure, blood lipids, glucose, urinary F2-isoprostanes, C-reactive protein, insulin, and leptin were measured at baseline and after 8 weeks of intervention. Results Participants lost approximately 4.7 ± 2.2 kg (p < 0.001). Weight loss was not significant between the RB + PS and RB group (p = 0.056). Changes in body fat corresponded to changes in body weight. Average decrease in total cholesterol was significantly higher in the RB + PS group than in the RB group (difference 36 ± 25 g/dL vs 7 ± 16 g/dL; p = 0.044). A similar pattern was observed for the decrease in low-density lipoprotein (LDL) cholesterol (difference 22.3 ± 25.2 g/dL vs 4.4 ± 18.9 g/dL; p = 0.062). Changes in systolic blood pressure, serum levels of leptin, and F2-isoprostanes were significant between baseline values and after 8 weeks on the diet in both groups (p < 0.05) but did not differ between the 2 groups. Conclusions A nutrient-balanced and energy-restricted diet supplemented with rice bran and plant sterols resulted in a significant decrease in total and LDL cholesterol in overweight and obese adults. PMID

  6. Gasification of agricultural residues in a demonstrative plant: Vine pruning and rice husks.

    PubMed

    Biagini, Enrico; Barontini, Federica; Tognotti, Leonardo

    2015-10-01

    Tests with vine pruning and rice husks were carried out in a demonstrative downdraft gasifier (350 kW), to prove the reactor operability, quantify the plant efficiency, and thus extend the range of potential energy feedstocks. Pressure drops, syngas flow rate and composition were monitored to study the material and energy balances, and performance indexes. Interesting results were obtained for vine pruning (syngas heating value 5.7 MJ/m(3), equivalent ratio 0.26, cold gas efficiency 65%, power efficiency 21%), while poorer values were obtained for rice husks (syngas heating value 2.5-3.8 MJ/m(3), equivalent ratio 0.4, cold gas efficiency 31-42%, power efficiency 10-13%). The work contains also a comparison with previous results (wood pellets, corn cobs, Miscanthus) for defining an operating diagram, based on material density and particle size and shape, and the critical zones (reactor obstruction, bridging, no bed buildup, combustion regime). Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Efficient use of energy in anoxia-tolerant plants with focus on germinating rice seedlings.

    PubMed

    Atwell, Brian J; Greenway, Hank; Colmer, Timothy D

    2015-04-01

    Anoxia tolerance in plants is distinguished by direction of the sparse supply of energy to processes crucial to cell maintenance and sometimes to growth, as in rice seedlings. In anoxic rice coleoptiles energy is used to synthesise proteins, take up K(+) , synthesise cell walls and lipids, and in cell maintenance. Maintenance of electrochemical H(+) gradients across the tonoplast and plasma membrane is crucial for solute compartmentation and thus survival. These gradients sustain some H(+) -solute cotransport and regulate cytoplasmic pH. Pyrophosphate (PPi ), the alternative energy donor to ATP, allows direction of energy to the vacuolar H(+) -PPi ase, sustaining H(+) gradients across the tonoplast. When energy production is critically low, operation of a biochemical pHstat allows H(+) -solute cotransport across plasma membranes to continue for at least for 18 h. In active (e.g. growing) cells, PPi produced during substantial polymer synthesis allows conversion of PPi to ATP by PPi -phosphofructokinase (PFK). In quiescent cells with little polymer synthesis and associated PPi formation, the PPi required by the vacuolar H(+) -PPi ase and UDPG pyrophosphorylase involved in sucrose mobilisation via sucrose synthase might be produced by conversion of ATP to PPi through reversible glycolytic enzymes, presumably pyruvate orthophosphate dikinase. These hypotheses need testing with species characterised by contrasting anoxia tolerance.

  8. Evaluation of plant growth promoting and colonization ability of endophytic diazotrophs from deep water rice.

    PubMed

    Verma, S C; Ladha, J K; Tripathi, A K

    2001-10-04

    A study of the diversity of endophytic bacteria present in seeds of a deepwater rice variety revealed the presence of seven types of BOX-PCR fingerprints. In order to evaluate the plant growth promoting potential the presence of nitrogenase, indole acetic acid production and mineral phosphate solubilization were estimated in the representative BOX-PCR types. The seven representatives of BOX-PCR types produced indole acetic acid, reduced acetylene and showed specific immunological cross-reaction with anti-dinitrogenase reductase antibody. Only four types showed mineral phosphate solubilizing ability. Comparison of cellulase and pectinase activities showed differences among different BOX-PCR types. PCR fingerprinting data showed that one strain isolated from the surface sterilized seeds as well as the aerial parts of the seedlings of rice variety showed low cellulase and pectinase but relatively high ARA. On the basis of 16S rDNA nucleotide sequence and BIOLOG system of bacterial identification, this strain was identified as Pantoea agglomerans. For studying the endophytic colonization this strain was genetically tagged with the reporter gene, gusA. Histochemical analysis of the seedling grown in hydroponics showed that the tagged strain colonized the root surface, root hairs, root cap, points of lateral root emergence, root cortex and the stelar region. Treatment of the roots with 2,4-D produced short thickened lateral roots which showed better colonization by P. agglomerans.

  9. Evaluation of Streptomyces spp. for their plant-growth-promotion traits in rice.

    PubMed

    Gopalakrishnan, Subramaniam; Vadlamudi, Srinivas; Apparla, Shravya; Bandikinda, Prakash; Vijayabharathi, Rajendran; Bhimineni, Ratna Kumari; Rupela, Om

    2013-08-01

    Five strains of Streptomyces (CAI-17, CAI-68, CAI-78, KAI-26, and KAI-27) were previously reported to have potential for charcoal rot control and plant growth promotion (PGP) in sorghum. In this study, those 5 Streptomyces strains were characterized for their enzymatic activities and evaluated for their PGP capabilities on rice. All the Streptomyces strains were able to produce lipase and β-1,3-glucanase; grew in NaCl (up to 8%), at pH 5-13, and at temperatures 20-40 °C; and were resistant to ampicillin, sensitive to nalidixic acid, and highly sensitive to chloramphenicol, kanamycin, streptomycin, and tetracycline. They were highly tolerant to the fungicide bavistin but were highly sensitive to benlate, benomyl, and radonil. When evaluated on rice in the field, Streptomyces significantly enhanced tiller and panicle numbers, stover and grain yields, dry matter, root length, volume and dry weight, compared with the control. In the rhizosphere at harvest, microbial biomass carbon and nitrogen, dehydrogenase activity, total nitrogen, available phosphorus, and % organic carbon were also found significantly higher in Streptomyces-treated plots than in the control plots. This study further confirms that the selected Streptomyces have PGP activities.

  10. Bacillus safensis with plant-derived smoke stimulates rice growth under saline conditions.

    PubMed

    Khan, Muhammad Hafeez Ullah; Khattak, Jabar Zaman Khan; Jamil, Muhammad; Malook, Ijaz; Khan, Shahid Ullah; Jan, Mehmood; Din, Ismail; Saud, Shah; Kamran, Muhammad; Alharby, Hesham; Fahad, Shah

    2017-09-03

    Salinity is a worldwide environmental problem of agricultural lands. Smoke and plant growth-promoting bacteria (PGPR) are individually used to improve plant growth, but the combined effects of these have not been studied yet under saline conditions. The combined effect of plant growth-promoting bacteria Bacillus safensis and plant-derived smoke Cymbopogon jwarancusa was studied under different salinity level as 50, 100, and 150 mM on rice (cv. Basmati-385). Smoke dilutions of C. jwarancusa (C-500 and C-1000) and bacterial culture of B. safensis were used to soak seeds for 10 h. It was observed that the salt concentration decreases the germination percentage, vegetative growth, ion contents (K(+) and Ca(2+)), and photosynthetic pigments (Chl "a," Chl "b," and carotene) while an increase occurred in Na(+), total soluble protein (TSP), proline, total soluble sugar, catalase (CAT), and peroxidase (POD) contents. The combined effect of B. safensis and smoke primed seeds increased the germination percentage, seedling growth, ion contents (K(+), Ca(2+)), and photosynthetic pigments (Chl "a," Chl "b," carotene) and reduced the Na(+) ion content, total soluble protein, proline content, total soluble sugar, CAT, and POD activity by lowering the drastic effect of salt stress. It was concluded that combined effect of smoke and PGPR is more effective than individual effect.

  11. Generation and Analysis of Transposon Ac/Ds-Induced Chromosomal Rearrangements in Rice Plants.

    PubMed

    Xuan, Yuan Hu; Peterson, Thomas; Han, Chang-Deok

    2016-01-01

    Closely-located transposable elements (TEs) have been known to induce chromosomal breakage and rearrangements via alternative transposition. To study genome rearrangements in rice, an Ac/Ds system has been employed. This system comprises an immobile Ac element expressed under the control of CaMV 35S promoter, and a modified Ds element. A starter line carried Ac and a single copy of Ds at the OsRLG5 (Oryza sativa receptor-like gene 5). To enhance the transpositional activity, seed-derived calli were cultured and regenerated into plants. Among 270 lines regenerated from the starter, one line was selected that contained a pair of inversely-oriented Ds elements at the OsRLG5 (Oryza sativa receptor-like gene 5). The selected line was again subjected to tissue culture to obtain a regenerant population. Among 300 regenerated plants, 107 (36 %) contained chromosomal rearrangements including deletions, duplications, and inversions of various sizes. From 34 plants, transposition mechanisms leading to such genomic rearrangements were analyzed. The rearrangements were induced by sister chromatid transposition (SCT), homologous recombination (HR), and single chromatid transposition (SLCT). Among them, 22 events (65 %) were found to be transmitted to the next generation. These results demonstrate a great potential of tissue culture regeneration and the Ac/Ds system in understanding alternative transposition mechanisms and in developing chromosome engineering in plants.

  12. Estimation of the rice-planting field in Bangladesh by satellite remote sensing

    NASA Astrophysics Data System (ADS)

    Furuta, E.; Suzuki, G.; Yamassaki, M.; Teraoka, T.; Fujiwara, H.; Ogino, Y.; Akashi, M.; Lahrita, L.; Naruse, N.; Takahashi, Y.

    2016-12-01

    In Bangladesh, price of rice has been unstable due to a large increase in production. To control the price can become a political issue, because rice agriculture is one of the most important industries in Bangladesh, whereas the total area of the paddy field is accurately unknown, owing to unsustainable and on-site surveys for the area (1). Satellite remote sensing is an effective solution to research the all area of domestic paddy field. Microwave satellite imaging has a large merit to be observable regardless of the weather conditions, however, research institutions have been limited to observing continuously since the cost is high for developing countries, such as Bangladesh. This study aims to establish the way to grasp the paddy field using optical satellite images for free of charge (Landsat-8). We have focused on seasonal changes in the water and the vegetation indices obtained from paddy fields. We have performed image calculations of Normalized Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI) of the well-known paddy field in Bangladesh Rice Research Institute. We found that there are seasonal changes of NDVI and NDWI calculated from paddy field. The characteristics are as follows; the NDVI and the NDWI values varies by 0.17-0.25 up and 0.11-0.19 down, respectively, at the transition from the dry to the rainy season, on the other hand, the NDVI and the NDWI changes by 0.21-0.29 down and 0.09-0.17 up from the rainy to the dry season. These features make us to distinguish the paddy field from the other cultivated area. The decrease of NDVI means that rice bares, The increase of NDWI can be interpreted that the paddy field is covered with water for the preparation for planting it. Our estimated area of paddy field in Bangladesh (85,900km ) corresponds well with the previous reported value of 117,700km (1). We have established the way to grasp the paddy field using optical satellite images for free of charge, on the bases of the

  13. Biochar increases plant available water in a sandy soil under an aerobic rice cropping system

    NASA Astrophysics Data System (ADS)

    de Melo Carvalho, M. T.; de Holanda Nunes Maia, A.; Madari, B. E.; Bastiaans, L.; van Oort, P. A. J.; Heinemann, A. B.; Soler da Silva, M. A.; Petter, F. A.; Meinke, H.

    2014-03-01

    The main objective of this study was to assess the impact of biochar rate (0, 8, 16 and 32 t ha-1) on the water retention capacity (WRC) of a sandy Dystric Plinthosol. The applied biochar was a by-product of slow pyrolysis (∼450 °C) of eucalyptus wood, milled to pass through a 2000 μm sieve that resulted in a material with an intrinsic porosity ≤10 μm and a specific surface area of ∼3.2 m2 g-1. The biochar was incorporated into the top 15 cm of the soil under an aerobic rice system. Our study focused on both the effects on WRC and rice yields at 2 and 3 years after application. Undisturbed soil samples were collected from 16 plots in two soil layers (5-10 and 15-20 cm). Soil water retention curves were modelled using a nonlinear mixed model which appropriately accounts for uncertainties inherent of spatial variability and repeated measurements taken within a specific soil sample. We found an increase in plant available water in the upper soil layer proportional to the rate of biochar, with about 0.8% for each t ha-1 of biochar amendment at 2 and 3 years after application. The impact of biochar on soil WRC was most likely related to an increase in overall porosity of the sandy soil, which was evident from an increase in saturated soil moisture and macro porosity with 0.5% and 1.6% for each t ha-1 of biochar applied, respectively. The increment in soil WRC did not translate into an increase in rice yield, essentially because in both seasons the amount of rainfall during critical period for rice production exceeded 650 mm. The use of biochar as a soil amendment can be a worthy strategy to guarantee yield stability under water limited conditions. Our findings raise the importance of assessing the feasibility of very high application rates of biochar and the inclusion of a detailed analysis of its physical and chemical properties as part of future investigations.

  14. Diurnal and phenological variations of O 3 and CO 2 fluxes of rice canopy exposed to different O 3 concentrations

    NASA Astrophysics Data System (ADS)

    Tong, Lei; Wang, Xiaoke; Geng, Chunmei; Wang, Wei; Lu, Fei; Song, Wenzhi; Liu, Hongjie; Yin, Baohui; Sui, Lihua; Wang, Qiong

    2011-10-01

    A dynamic chamber system was designed to measure simultaneously the diurnal and phenological canopy ozone (O 3) and carbon dioxide (CO 2) fluxes in the paddy field under different O 3 concentrations (0, 40, 80 and 120 nmol mol -1). On the diurnal timescale, a decreasing trend of canopy O 3 flux was observed from morning to evening and the O 3 flux increased with increasing O 3 concentration, while canopy CO 2 flux generally followed the track of photosynthetic active radiation, with higher values at noon except at the end of the growing season when rice was senescent. The constant CO 2 flux among different O 3 treatments in this experiment suggested that the photosynthesis of the rice canopy was not affected by short-duration (ca. 10 min) O 3 exposure of elevated concentration. The daily mean O 3 and CO 2 fluxes increased with rice growth until the dough stage and the late jointing stage, respectively, then decreased with rice aging. The peak values of O 3 flux appeared later than those of CO 2 flux because the latter was closely synchronized with the leaf area index of the rice canopy. Diurnal mean canopy O 3 flux varied from 18.7 to 43.3 nmol m -2 s -1, and nocturnal mean canopy O 3 flux varied from 2.7 to 17.8 nmol m -2 s -1 and from 7.0 to 25.4 nmol m -2 s -1 for the 40 and 80 nmol mol -1 O 3 treatments, respectively. The considerable amount of nocturnal O 3 flux indicated a significant contribution of non-stomatal factors to canopy O 3 uptake. The adjusted Jarvis multiplicative models were used and well parameterized to fit the measured O 3 and CO 2 fluxes of our rice cultivar from environmental variables. Although more validation work is needed, the present results suggest that the models can be considered as a tool for canopy flux predictions in the paddy field.

  15. Efficient generation of marker-free transgenic rice plants using an improved transposon-mediated transgene reintegration strategy.

    PubMed

    Gao, Xiaoqing; Zhou, Jie; Li, Jun; Zou, Xiaowei; Zhao, Jianhua; Li, Qingliang; Xia, Ran; Yang, Ruifang; Wang, Dekai; Zuo, Zhaoxue; Tu, Jumin; Tao, Yuezhi; Chen, Xiaoyun; Xie, Qi; Zhu, Zengrong; Qu, Shaohong

    2015-01-01

    Marker-free transgenic plants can be developed through transposon-mediated transgene reintegration, which allows intact transgene insertion with defined boundaries and requires only a few primary transformants. In this study, we improved the selection strategy and validated that the maize (Zea mays) Activator/Dissociation (Ds) transposable element can be routinely used to generate marker-free transgenic plants. A Ds-based gene of interest was linked to green fluorescent protein in transfer DNA (T-DNA), and a green fluorescent protein-aided counterselection against T-DNA was used together with polymerase chain reaction (PCR)-based positive selection for the gene of interest to screen marker-free progeny. To test the efficacy of this strategy, we cloned the Bacillus thuringiensis (Bt) δ-endotoxin gene into the Ds elements and transformed transposon vectors into rice (Oryza sativa) cultivars via Agrobacterium tumefaciens. PCR assays of the transposon empty donor site exhibited transposition in somatic cells in 60.5% to 100% of the rice transformants. Marker-free (T-DNA-free) transgenic rice plants derived from unlinked germinal transposition were obtained from the T1 generation of 26.1% of the primary transformants. Individual marker-free transgenic rice lines were subjected to thermal asymmetric interlaced-PCR to determine Ds(Bt) reintegration positions, reverse transcription-PCR and enzyme-linked immunosorbent assay to detect Bt expression levels, and bioassays to confirm resistance against the striped stem borer Chilo suppressalis. Overall, we efficiently generated marker-free transgenic plants with optimized transgene insertion and expression. The transposon-mediated marker-free platform established in this study can be used in rice and possibly in other important crops. © 2015 American Society of Plant Biologists. All Rights Reserved.

  16. Multiwalled carbon nanotubes enter broccoli cells enhancing growth and water uptake of plants exposed to salinity.

    PubMed

    Martínez-Ballesta, M Carmen; Zapata, Lavinia; Chalbi, Najla; Carvajal, Micaela

    2016-06-08

    Carbon nanotubes have been shown to improve the germination and growth of some plant species, extending the applicability of the emerging nano-biotechnology field to crop science. In this work, exploitation of commercial multiwalled carbon nanotubes (MWCNTs) in control and 100 mM NaCl-treated broccoli was performed. Transmission electron microscopy demonstrated that MWCNTs can enter the cells in adult plants with higher accumulation under salt stress. Positive effect of MWCNTs on growth in NaCl-treated plants was consequence of increased water uptake, promoted by more-favourable energetic forces driving this process, and enhanced net assimilation of CO2. MWCNTs induced changes in the lipid composition, rigidity and permeability of the root plasma membranes relative to salt-stressed plants. Also, enhanced aquaporin transduction occurred, which improved water uptake and transport, alleviating the negative effects of salt stress. Our work provides new evidences about the effect of MWCNTs on plasma membrane properties of the plant cell. The positive response to MWCNTs in broccoli plants opens novel perspectives for their technological uses in new agricultural practices, especially when 1plants are exposed to saline environments.

  17. Changes of primary and secondary metabolites in barley plants exposed to CdO nanoparticles.

    PubMed

    Večeřová, Kristýna; Večeřa, Zbyněk; Dočekal, Bohumil; Oravec, Michal; Pompeiano, Antonio; Tříska, Jan; Urban, Otmar

    2016-11-01

    The environmental fate of airborne nanoparticles and their toxicity to plants is not yet fully understood. Pot-grown barley plants with second leaves developed were therefore exposed to CdO nanoparticles (CdONPs) of ecologically relevant size (7-60 nm) and concentration (2.03 ± 0.45 × 10(5) particles cm(-3)) in air for 3 weeks. An experiment was designed to test the effects of different treatments when only leaves (T1); leaves and soil substrate (T2); and leaves, soil, and water supply were exposed to nanoparticles (T3). A fourth, control group of plants was left without treatment (T0). Although CdONPs were directly absorbed by leaves from the air, a part of leaf-allocated Cd was also transported from roots by transpiration flow. Chromatographic assays revealed that CdONPs had a significant effect on total content of primary metabolites (amino acids and saccharides) but no significant effect on total content of secondary metabolites (phenolic compounds, Krebs cycle acids, and fatty acids). In addition, the compositions of individual metabolite classes were affected by CdONP treatment. For example, tryptophan and phenylalanine were the most affected amino acids in both analysed organs, while ferulic acid and isovitexin constituted the polyphenols most affected in leaves. Even though CdONP treatment had no effect on total fatty acids content, there were significant changes in the composition of saturated and unsaturated fatty acids in both the roots and leaves of treated plants. Although the results indicate the most pronounced effect in T3 plants as compared to T1 and T2 plants, even just leaf exposure to CdONPs has the potential to induce changes in plant metabolism. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Circumnutation and its dependence on the gravity response in rice, morning glory and pea plants: verification by spaceflight experiments

    NASA Astrophysics Data System (ADS)

    Takahashi, Hideyuki; Kobayashi, Akie; Fujii, Nobuharu; Yano, Sachiko; Shimazu, Toru; Kim, Hyejeong; Tomita, Yuuta; Miyazawa, Yutaka

    Plant organs display helical growth movement known as circumnutation. This movement helps plant organs find suitable environmental cues. The amplitude, period and shape of the circumnutation differ depending on plant species or organs. Although the mechanism for circumnutation is unclear, it has long been argued whether circumnutation is involved with gravitropic response. Previously, we showed that shoots of weeping morning glory (we1 and we2) are impaired in not only the differentiation of endodermis (gravisensing cells) and gravitropic response, but also winding and circumnutation (Kitazawa et al., PNAS 102: 18742-18747, 2005). Here, we report a reduced circumnutation in the shoots of rice and the roots of pea mutants defective in gravitropic response. Coleoptiles of clinorotated rice seedlings and decapped roots of pea seedlings also showed a reduction of their circumnutational movement. These results suggest that circumnutation is tightly related with gravitropic response. In the proposed spaceflight experiments, “Plant Rotation”, we will verify the hypothesis that circumnutation requires gravity response, by using microgravity environment in KIBO module of the International Space Station. We will grow rice and morning glory plants under both muG and 1G conditions on orbit and monitor their growth by a camera. The downlinked images will be analyzed for the measurements of plant growth and nutational movements. This experiment will enable us to answer the question whether circumnutation depends on gravity response or not.

  19. Increased Susceptibility to Aphids of Flowering Wheat Plants Exposed to Low Temperatures.

    PubMed

    Lacoste, C; Nansen, C; Thompson, S; Moir-Barnetson, L; Mian, A; McNee, M; Flower, K C

    2015-06-01

    Frost is known to directly affect flowering wheat plants (Triticum aestivum L.) and lead to reduced grain yield. Additionally, it may increase wheat susceptibility to economically important pests, such as aphids (Hemiptera: Aphididae). Wheat plants at flowering stage were exposed to one of the three temperature treatments: ambient (11-12°C), 0°C, and -3°C for 60 min. Preference (3-choice) and performance (no-choice) bioassays with aphids (Rhopalosiphum padi L.) were conducted 1, 3, 6, and 12 d after temperature treatments to assess effects of temperature-induced stress over time. As an initial feasibility study of using remote sensing technologies to detect frost-induced stress in flowering wheat plants, hyperspectral imaging data were acquired from wheat plants used in preference bioassays. Element analysis of wheat plants was included to determine the effect of temperature-induced stress on the nutritional composition of flowering wheat plants. The results from this study support the following cause-effect scenario: a 60-min exposure to low temperatures caused a significant decrease in potassium and copper content of wheat plants 6 d after temperature exposure, and it coincided with a marked increase in preference by aphids of wheat plants. The preference exhibited by aphids correlated positively with performance of aphids, so the preference-performance hypothesis was confirmed and possibly driven by potassium and copper content of wheat plants. In addition, we demonstrated that hyperspectral imaging data can be used to detect frost-induced susceptibility to aphid infestation in flowering wheat plants. These findings justify further research into airborne remote sensing of frost-induced stress and the possible secondary effects on crop susceptibility to arthropod pests. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. The effect of silicon on the leaf proteome of rice (Oryza sativa L.) plants under cadmium-stress.

    PubMed

    Nwugo, Chika C; Huerta, Alfredo J

    2011-02-04

    The best known silicon (Si)-accumulating plant, rice (Oryza sativa L.), stores most of its Si in leaves, but the importance of Si has been limited to a mechanical role. Our initial studies showed that Si-induced cadmium (Cd) tolerance is mediated by the enhancement of instantaneous water-use-efficiency, carboxylation efficiency of ribulose-1,5-bisphosphate carboxylase oxygenase (RuBisCO), and light-use-efficiency in leaves of rice plants. In this study, we investigated changes in the rice leaf proteome in order to identify molecular mechanisms involved in Si-induced Cd tolerance. Our study identified 60 protein spots that were differentially regulated due to Cd and/or Si treatments. Among them, 50 were significantly regulated by Si, including proteins associated with photosynthesis, redox homeostasis, regulation/protein synthesis, pathogen response and chaperone activity. Interestingly, we observed a Si-induced up-regulation of a class III peroxidase and a thaumatin-like protein irrespective of Cd treatment, in addition to a Cd-induced up-regulation of protein disulfide isomerase, a HSP70 homologue, a NADH-ubiquinone oxidoreductase, and a putative phosphogluconate dehydrogenase, especially in the presence of Si. Taken together, our study sheds light on molecular mechanisms involved in Si-induced Cd tolerance in rice leaves and suggests a more active involvement of Si in plant physiological processes than previously proposed.

  1. An osmotin from the resurrection plant Tripogon loliiformis (TlOsm) confers tolerance to multiple abiotic stresses in transgenic rice.

    PubMed

    Le, Trang T T; Williams, Brett; Mundree, Sagadevan G

    2017-05-03

    Osmotin is a key protein associated with abiotic and biotic stress response in plants. In this study, an osmotin from the resurrection plant Tripogon loliiformis (TlOsm) was characterized and functionally analyzed under abiotic stress conditions in T. loliiformis as well as in transgenic Nicotiana tabacum (tobacco) and Oryza sativa (rice) plants. Real-time PCR analysis on mixed elicitor cDNA libraries from T. loliiformis showed that TlOsm was upregulated a 1000-fold during the early stages of osmotic stresses (cold, drought, and salinity) in both shoots and roots but downregulated in shoots during heat stress. There was no change in TlOsm gene expression in roots of heat-stressed plants and during plant development. The plasma membrane localization of TlOsm was showed in fluorescent-tagged TlOsm tobacco plants using confocal laser scanning microscopic analysis. Transgenic rice plants expressing TlOsm were assessed for enhanced tolerance to salinity, drought and cold stresses. Constitutively expressed TlOsm in transgenic rice plants showed increased tolerance to cold, drought and salinity stress when compared with the wild-type and vector control counterparts. This was evidenced by maintained growth, retained higher water content and membrane integrity, and improved survival rate of TlOsm-expressing plants. The results thus indicate the involvement of TlOsm in plant response to multiple abiotic stresses, possibly through the signaling pathway, and highlight its potential applications for engineering crops with improved tolerance to cold, drought and salinity stress. © 2017 Scandinavian Plant Physiology Society.

  2. Isomer pattern and elimination of dioxins in workers exposed at a municipal waste incineration plant

    PubMed Central

    YAMAMOTO, Kenya; KUDO, Mitsuhiro; ARITO, Heihachiro; OGAWA, Yasutaka; TAKATA, Tsutomu

    2015-01-01

    The aim of this study was to clarify patterns of serum concentrations of dioxins in the employees of a waste incineration plant and to estimate elimination rates and half-lives of serum dioxin isomers, and the maximum serum concentrations of dioxin isomers at the time of plant shutdown. Sixteen subjects participating 3 times or more in annual health examinations during an 8-yr period from 2000 to 2007 were recruited for this study. Serum concentrations of dioxins expressed as TEQ/g lipid decreased gradually after plant shutdown with the highest decrease observed in polychlorinated dibenzofurans (PCDFs) followed by polychlorinated deibenzo-p-dioxins (PCDDs) and then coplanar PCBs. The serum toxic equivalency (TEQ) concentrations of PCDF and PCDD congeners in the employees were higher than those in the general population survey by the Ministry of the Environment, Japan, whereas the serum concentrations of coplanar PCBs were similar to those in the general population. The estimated half-lives and elimination rates of PCDDs and PCDFs in the highly exposed workers increased compared with the moderately exposed workers. The estimated geometric mean serum concentrations of PCDDs, PCDFs and total dioxins at the time of plant shutdown were 35, 53 and 107 pg TEQ/g lipid, respectively. PMID:26118856

  3. Characterization of the origin recognition complex (ORC) from a higher plant, rice (Oryza sativa L.).

    PubMed

    Mori, Yoko; Yamamoto, Taichi; Sakaguchi, Norihiro; Ishibashi, Toyotaka; Furukawa, Tomoyuki; Kadota, Yasuhiro; Kuchitsu, Kazuyuki; Hashimoto, Junji; Kimura, Seisuke; Sakaguchi, Kengo

    2005-06-20

    The origin recognition complex (ORC) protein plays a critical role in DNA replication through binding to sites (origins) where replication commences. The protein is composed of six subunits (ORC1 to 6) in animals and yeasts. Our knowledge of the ORC protein in plants is, however, much less complete. We have performed cDNA cloning and characterization of ORC subunits in rice (Oryza sativa L. cv. Nipponbare) in order to facilitate study of plant DNA replication mechanisms. Our previous report provided a description of a gene, ORC1 (OsORC1), that encodes one of the protein subunits. The present report extends this initial analysis to include the genes that encode four other rice ORC subunits, OsORC2, 3, 4 and 5. Northern hybridization analyses demonstrated the presence of abundant transcripts for all OsORC subunits in shoot apical meristems (SAM) and cultured cells, but not in mature leaves. Interestingly, only OsORC5 showed high levels of expression in organs in which cell proliferation is not active, such as flag leaves, the ears and the non-tip roots. The pattern of expression of OsORC2 also differed from other OsORC subunits. When cell proliferation was temporarily halted for 6-10 days by removal of sucrose from the growth medium, expression of OsORC1, OsORC3, OsORC4 and OsORC5 was substantially reduced. However, the level of expression of OsORC2 remained constant. We suggest from these results that expression of OsORC1, 3, 4 and 5 are correlated with cell proliferation, but the expression of OsORC2 is not.

  4. Biochemical characterization of rice trehalose-6-phosphate phosphatases supports distinctive functions of these plant enzymes.

    PubMed

    Shima, Shuhei; Matsui, Hirokazu; Tahara, Satoshi; Imai, Ryozo

    2007-03-01

    Substantial levels of trehalose accumulate in bacteria, fungi, and invertebrates, where it serves as a storage carbohydrate or as a protectant against environmental stresses. In higher plants, trehalose is detected at fairly low levels; therefore, a regulatory or signaling function has been proposed for this molecule. In many organisms, trehalose-6-phosphate phosphatase is the enzyme governing the final step of trehalose biosynthesis. Here we report that OsTPP1 and OsTPP2 are the two major trehalose-6-phosphate phosphatase genes expressed in vegetative tissues of rice. Similar to results obtained from our previous OsTPP1 study, complementation analysis of a yeast trehalose-6-phosphate phosphatase mutant and activity measurement of the recombinant protein demonstrated that OsTPP2 encodes a functional trehalose-6-phosphate phosphatase enzyme. OsTPP2 expression is transiently induced in response to chilling and other abiotic stresses. Enzymatic characterization of recombinant OsTPP1 and OsTPP2 revealed stringent substrate specificity for trehalose 6-phosphate and about 10 times lower K(m) values for trehalose 6-phosphate as compared with trehalose-6-phosphate phosphatase enzymes from microorganisms. OsTPP1 and OsTPP2 also clearly contrasted with microbial enzymes, in that they are generally unstable, almost completely losing activity when subjected to heat treatment at 50 degrees C for 4 min. These characteristics of rice trehalose-6-phosphate phosphatase enzymes are consistent with very low cellular substrate concentration and tightly regulated gene expression. These data also support a plant-specific function of trehalose biosynthesis in response to environmental stresses.

  5. Analysis of substrate specificity of pig CYP2B22 and CYP2C49 towards herbicides by transgenic rice plants.

    PubMed

    Kawahigashi, Hiroyuki; Hirose, Sakiko; Ozawa, Kenjirou; Ido, Yoshiko; Kojima, Misaki; Ohkawa, Hideo; Ohkawa, Yasunobu

    2005-12-01

    We introduced two novel types of pig (Sus scrofa) cytochrome P450, CYP2B22 and CYP2C49, into rice plants (Oryza sativa L. cv. 'Nipponbare') to produce herbicide-tolerant plants and to confirm the metabolic activities of the cytochrome P450 species. In germination tests, both types of transgenic plants showed tolerance to various herbicides with different modes of action. CYP2B22 rice plants showed tolerance towards 12 herbicides including chlortoluron (100 microM), amiprofos-methyl (2.5 microM), pendimethalin (10 microM), metolachlor (2.5 microM), and esprocarb (20 microM). CYP2C49 rice plants showed tolerance towards 13 herbicides, including chlortoluron (100 microM), norflurazon (0.5 microM), amiprofos-methyl (2.5 microM), alachlor (0.8 microM), and isoxaben (1 microM). The herbicide tolerance was considered to reflect the substrate specificity of the introduced P450 species. We used (14)C-labeled metolachlor and norflurazon to confirm the P450 activity in the transgenic rice plants. The herbicides were metabolized more quickly in the transgenic rice plants than in the nontransgenic rice plants. Therefore, CYP2B22 and CYP2C49 rice plants became more tolerant to various herbicides than nontransgenic control plants because of accelerated metabolism of the herbicides by the introduced P450 species. Assuming that public and commercial acceptance is forthcoming, these transgenic rice plants may become useful tools for the breeding of herbicide-tolerant crops.

  6. Comparative transcriptomics of rice plants under cold, iron, and salt stresses.

    PubMed

    do Amaral, Marcelo Nogueira; Arge, Luis Willian Pacheco; Benitez, Letícia Carvalho; Danielowski, Rodrigo; Silveira, Solange Ferreira da Silveira; Farias, Daniel da Rosa; de Oliveira, Antonio Costa; da Maia, Luciano Carlos; Braga, Eugenia Jacira Bolacel

    2016-09-01

    Abiotic stresses such as salinity, iron toxicity, and low temperatures are the main limiting factors of rice (Oryza sativa L.) yield. The elucidation of the genes involved in responses to these stresses is extremely important to understand the mechanisms that confer tolerance, as well as for the development of cultivars adapted to these conditions. In this study, the RNA-seq technique was used to compare the transcriptional profile of rice leaves (cv. BRS Querência) in stage V3, exposed to cold, iron, and salt stresses for 24 h. A range of 41 to 51 million reads was aligned, in which a total range of 88.47 to 89.21 % was mapped in the reference genome. For cold stress, 7905 differentially expressed genes (DEGs) were observed, 2092 for salt and 681 for iron stress; 370 of these were common to the three DEG stresses. Functional annotation by software MapMan demonstrated that cold stress usually promoted the greatest changes in the overall metabolism, and an enrichment analysis of overrepresented gene ontology (GO) terms showed that most of them are contained in plastids, ribosome, and chloroplasts. Saline stress induced a more complex interaction network of upregulated overrepresented GO terms with a relatively low number of genes compared with cold stress. Our study demonstrated a high number of differentially expressed genes under cold stress and a greater relationship between salt and iron stress levels. The physiological process most affected at the molecular level by the three stresses seems to be photosynthesis.

  7. Genome-Wide Association Study for Traits Related to Plant and Grain Morphology, and Root Architecture in Temperate Rice Accessions.

    PubMed

    Biscarini, Filippo; Cozzi, Paolo; Casella, Laura; Riccardi, Paolo; Vattari, Alessandra; Orasen, Gabriele; Perrini, Rosaria; Tacconi, Gianni; Tondelli, Alessandro; Biselli, Chiara; Cattivelli, Luigi; Spindel, Jennifer; McCouch, Susan; Abbruscato, Pamela; Valé, Giampiero; Piffanelli, Pietro; Greco, Raffaella

    2016-01-01

    In this study we carried out a genome-wide association analysis for plant and grain morphology and root architecture in a unique panel of temperate rice accessions adapted to European pedo-climatic conditions. This is the first study to assess the association of selected phenotypic traits to specific genomic regions in the narrow genetic pool of temperate japonica. A set of 391 rice accessions were GBS-genotyped yielding-after data editing-57000 polymorphic and informative SNPS, among which 54% were in genic regions. In total, 42 significant genotype-phenotype associations were detected: 21 for plant morphology traits, 11 for grain quality traits, 10 for root architecture traits. The FDR of detected associations ranged from 3 · 10-7 to 0.92 (median: 0.25). In most cases, the significant detected associations co-localised with QTLs and candidate genes controlling the phenotypic variation of single or multiple traits. The most significant associations were those for flag leaf width on chromosome 4 (FDR = 3 · 10-7) and for plant height on chromosome 6 (FDR = 0.011). We demonstrate the effectiveness and resolution of the developed platform for high-throughput phenotyping, genotyping and GWAS in detecting major QTLs for relevant traits in rice. We identified strong associations that may be used for selection in temperate irrigated rice breeding: e.g. associations for flag leaf width, plant height, root volume and length, grain length, grain width and their ratio. Our findings pave the way to successfully exploit the narrow genetic pool of European temperate rice and to pinpoint the most relevant genetic components contributing to the adaptability and high yield of this germplasm. The generated data could be of direct use in genomic-assisted breeding strategies.

  8. Genome-Wide Association Study for Traits Related to Plant and Grain Morphology, and Root Architecture in Temperate Rice Accessions

    PubMed Central

    Cozzi, Paolo; Casella, Laura; Riccardi, Paolo; Vattari, Alessandra; Orasen, Gabriele; Perrini, Rosaria; Tacconi, Gianni; Tondelli, Alessandro; Biselli, Chiara; Cattivelli, Luigi; Spindel, Jennifer; McCouch, Susan; Abbruscato, Pamela; Valé, Giampiero; Piffanelli, Pietro; Greco, Raffaella

    2016-01-01

    Background In this study we carried out a genome-wide association analysis for plant and grain morphology and root architecture in a unique panel of temperate rice accessions adapted to European pedo-climatic conditions. This is the first study to assess the association of selected phenotypic traits to specific genomic regions in the narrow genetic pool of temperate japonica. A set of 391 rice accessions were GBS-genotyped yielding—after data editing—57000 polymorphic and informative SNPS, among which 54% were in genic regions. Results In total, 42 significant genotype-phenotype associations were detected: 21 for plant morphology traits, 11 for grain quality traits, 10 for root architecture traits. The FDR of detected associations ranged from 3 · 10−7 to 0.92 (median: 0.25). In most cases, the significant detected associations co-localised with QTLs and candidate genes controlling the phenotypic variation of single or multiple traits. The most significant associations were those for flag leaf width on chromosome 4 (FDR = 3 · 10−7) and for plant height on chromosome 6 (FDR = 0.011). Conclusions We demonstrate the effectiveness and resolution of the developed platform for high-throughput phenotyping, genotyping and GWAS in detecting major QTLs for relevant traits in rice. We identified strong associations that may be used for selection in temperate irrigated rice breeding: e.g. associations for flag leaf width, plant height, root volume and length, grain length, grain width and their ratio. Our findings pave the way to successfully exploit the narrow genetic pool of European temperate rice and to pinpoint the most relevant genetic components contributing to the adaptability and high yield of this germplasm. The generated data could be of direct use in genomic-assisted breeding strategies. PMID:27228161

  9. SET DOMAIN GROUP701 encodes a H3K4-methytransferase and regulates multiple key processes of rice plant development.

    PubMed

    Liu, Kunpeng; Yu, Yu; Dong, Aiwu; Shen, Wen-Hui

    2017-07-01

    Chromatin-based epigenetic information plays an important role in developmental gene regulation, in response to environment, and in natural variation of gene expression levels. Histone H3 lysine 4 di/trimethylation (H3K4me2/3) is abundant in euchromatin and is generally associated with transcriptional activation. Strikingly, however, enzymes catalyzing H3K4me2/3 remain poorly characterized in crops so far. Here, we investigated the function of the rice SET DOMAIN GROUP 701 (SDG701) gene by molecular and biochemical characterization of the gene product, and by studying effects of its loss or gain of function on plant growth and development. We demonstrated that SDG701 encodes a methytransferase specifically catalyzing H3K4 methylation. Overexpression and knockdown experiments showed that SDG701 is crucial for proper sporophytic plant development as well as for gametophytic transmission that directly impacts rice grain production. In-depth analysis of plant flowering time revealed that SDG701 promotes rice flowering under either long-day or short-day photoperiods. Consistently, the SDG701 protein was found to bind chromatin to promote H3K4me3 and to enhance expression of the rice Hd3a and RFT1 florigens. Collectively, our results establish SDG701 as a major rice H3K4-specific methyltransferase and provide important insights into function of H3K4me3 deposition in transcription activation of florigens in promoting plant flowering. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  10. Efficient Generation of Marker-Free Transgenic Rice Plants Using an Improved Transposon-Mediated Transgene Reintegration Strategy1

    PubMed Central

    Gao, Xiaoqing; Zhou, Jie; Li, Jun; Zou, Xiaowei; Zhao, Jianhua; Li, Qingliang; Xia, Ran; Yang, Ruifang; Wang, Dekai; Zuo, Zhaoxue; Tu, Jumin; Tao, Yuezhi; Chen, Xiaoyun; Xie, Qi; Zhu, Zengrong

    2015-01-01

    Marker-free transgenic plants can be developed through transposon-mediated transgene reintegration, which allows intact transgene insertion with defined boundaries and requires only a few primary transformants. In this study, we improved the selection strategy and validated that the maize (Zea mays) Activator/Dissociation (Ds) transposable element can be routinely used to generate marker-free transgenic plants. A Ds-based gene of interest was linked to green fluorescent protein in transfer DNA (T-DNA), and a green fluorescent protein-aided counterselection against T-DNA was used together with polymerase chain reaction (PCR)-based positive selection for the gene of interest to screen marker-free progeny. To test the efficacy of this strategy, we cloned the Bacillus thuringiensis (Bt) δ-endotoxin gene into the Ds elements and transformed transposon vectors into rice (Oryza sativa) cultivars via Agrobacterium tumefaciens. PCR assays of the transposon empty donor site exhibited transposition in somatic cells in 60.5% to 100% of the rice transformants. Marker-free (T-DNA-free) transgenic rice plants derived from unlinked germinal transposition were obtained from the T1 generation of 26.1% of the primary transformants. Individual marker-free transgenic rice lines were subjected to thermal asymmetric interlaced-PCR to determine Ds(Bt) reintegration positions, reverse transcription-PCR and enzyme-linked immunosorbent assay to detect Bt expression levels, and bioassays to confirm resistance against the striped stem borer Chilo suppressalis. Overall, we efficiently generated marker-free transgenic plants with optimized transgene insertion and expression. The transposon-mediated marker-free platform established in this study can be used in rice and possibly in other important crops. PMID:25371551

  11. Root morphology, hydraulic conductivity and plant water relations of high-yielding rice grown under aerobic conditions

    PubMed Central

    Kato, Yoichiro; Okami, Midori

    2011-01-01

    Background and Aims Increasing physical water scarcity is a major constraint for irrigated rice (Oryza sativa) production. ‘Aerobic rice culture’ aims to maximize yield per unit water input by growing plants in aerobic soil without flooding or puddling. The objective was to determine (a) the effect of water management on root morphology and hydraulic conductance, and (b) their roles in plant–water relationships and stomatal conductance in aerobic culture. Methods Root system development, stomatal conductance (gs) and leaf water potential (Ψleaf) were monitored in a high-yielding rice cultivar (‘Takanari’) under flooded and aerobic conditions at two soil moisture levels [nearly saturated (> –10 kPa) and mildly dry (> –30 kPa)] over 2 years. In an ancillary pot experiment, whole-plant hydraulic conductivity (soil-leaf hydraulic conductance; Kpa) was measured under flooded and aerobic conditions. Key Results Adventitious root emergence and lateral root proliferation were restricted even under nearly saturated conditions, resulting in a 72–85 % reduction in total root length under aerobic culture conditions. Because of their reduced rooting size, plants grown under aerobic conditions tended to have lower Kpa than plants grown under flooded conditions. Ψleaf was always significantly lower in aerobic culture than in flooded culture, while gs was unchanged when the soil moisture was at around field capacity. gs was inevitably reduced when the soil water potential at 20-cm depth reached –20 kPa. Conclusions Unstable performance of rice in water-saving cultivations is often associated with reduction in Ψleaf. Ψleaf may reduce even if Kpa is not significantly changed, but the lower Ψleaf would certainly occur in case Kpa reduces as a result of lower water-uptake capacity under aerobic conditions. Rice performance in aerobic culture might be improved through genetic manipulation that promotes lateral root branching and rhizogenesis as well as deep

  12. Greenhouse gas emissions from rice microcosms amended with a plant microbial fuel cell.

    PubMed

    Arends, Jan B A; Speeckaert, Jonas; Blondeel, Evelyne; De Vrieze, Jo; Boeckx, Pascal; Verstraete, Willy; Rabaey, Korneel; Boon, Nico

    2014-04-01

    Methane (CH4) release from wetlands is an important source of greenhouse gas emissions. Gas exchange occurs mainly through the aerenchyma of plants, and production of greenhouse gases is heavily dependent on rhizosphere biogeochemical conditions (i.e. substrate availability and redox potential). It is hypothesized that by introducing a biocatalyzed anode electrode in the rhizosphere of wetland plants, a competition for carbon and electrons can be invoked between electrical current-generating bacteria and methanogenic Archaea. The anode electrode is part of a bioelectrochemical system (BES) capable of harvesting electrical current from microbial metabolism. In this work, the anode of a BES was introduced in the rhizosphere of rice plants (Oryza sativa), and the impact on methane emissions was monitored. Microbial current generation was able to outcompete methanogenic processes when the bulk matrix contained low concentrations of organic carbon, provided that the electrical circuit with the effective electroactive microorganisms was in place. When interrupting the electrical circuit or supplying an excess of organic carbon, methanogenic metabolism was able to outcompete current generating metabolism. The qPCR results showed hydrogenotrophic methanogens were the most abundant methanogenic group present, while mixotrophic or acetoclastic methanogens were hardly detected in the bulk rhizosphere or on the electrodes. Competition for electron donor and acceptor were likely the main drivers to lower methane emissions. Overall, electrical current generation with BESs is an interesting option to control CH4 emissions from wetlands but needs to be applied in combination with other mitigation strategies to be successful and feasible in practice.

  13. Interaction between two rice mitogen activated protein kinases and its possible role in plant defense

    PubMed Central

    2013-01-01

    Background The canonical mitogen activated protein kinase (MAPK) signaling pathway plays a vital role in carrying out the normal growth and development of the plant. The pathway, connecting the upstreams signal with the downstream target is considered to be linear, mostly starting with a MAPKKK and ending in a MAPK. Results Here we report a novel interaction between two rice MAPKs, OsMPK20-4 and OsMPK3 suggesting the complex nature of the pathway rather than a linear one at individual steps. The interaction between OsMPK20-4 and OsMPK3 found by yeast two-hybrid analysis was confirmed in planta by co-immunoprecipitation and fluorescence resonance energy transfer (FRET) assays. The interaction is specific and is phosphorylation independent. The results suggest a role of the interaction between OsMPK20-4 and OsMPK3 in basic plant defense. Conclusions The current novel work showing the physical interaction between two plant MAPKs, OsMPK20-4 and OsMPK3 is the diversion from the dogma of a typical MAPK cascade thereby opening a new dimension to the MAPK signal transduction. PMID:23984709

  14. Rice cytokinin GATA transcription Factor1 regulates chloroplast development and plant architecture.

    PubMed

    Hudson, Darryl; Guevara, David R; Hand, Andrew J; Xu, Zhenhua; Hao, Lixin; Chen, Xi; Zhu, Tong; Bi, Yong-Mei; Rothstein, Steven J

    2013-05-01

    Chloroplast biogenesis has been well documented in higher plants, yet the complex methods used to regulate chloroplast activity under fluctuating environmental conditions are not well understood. In rice (Oryza sativa), the CYTOKININ-RESPONSIVE GATA TRANSCRIPTION FACTOR1 (Cga1) shows increased expression following light, nitrogen, and cytokinin treatments, while darkness and gibberellin reduce expression. Strong overexpression of Cga1 produces dark green, semidwarf plants with reduced tillering, whereas RNA interference knockdown results in reduced chlorophyll and increased tillering. Coexpression, microarray, and real-time expression analyses demonstrate a correlation between Cga1 expression and the expression of important nucleus-encoded, chloroplast-localized genes. Constitutive Cga1 overexpression increases both chloroplast biogenesis and starch production but also results in delayed senescence and reduced grain filling. Growing the transgenic lines under different nitrogen regimes indicates potential agricultural applications for Cga1, including manipulation of biomass, chlorophyll/chloroplast content, and harvest index. These results indicate a conserved mechanism by which Cga1 regulates chloroplast development in higher plants.

  15. Activity of chlorantraniliprole and thiamethoxam seed treatments on life stages of the rice water weevil as affected by the distribution of insecticides in rice plants.

    PubMed

    Lanka, Srinivas K; Stout, Michael J; Beuzelin, Julien M; Ottea, James A

    2014-02-01

    The systemic insecticides chlorantraniliprole (CAP) and thiamethoxam (TMX), applied to rice as seed treatments, may affect multiple life stages of the rice water weevil, Lissorhoptrus oryzophilus. Effects of CAP and TMX on adult survival, egg-laying and first- and late-instar survivals were determined by infesting plants treated as seeds with different rates of insecticides. The biological activity was related to insecticidal concentrations in leaves, shoots and roots. CAP did not affect adult survival but decreased egg numbers and reduced the survival of the first and late instars. The greatest reduction in weevil population occurred in late instars feeding on roots. In contrast, TMX reduced adult survival and egg and larval numbers. The high biological activity of CAP on root-feeding stages was consistent with the accumulation of CAP in roots, whereas in TMX-treated plants the high activity on adults correlated with high concentrations of TMX in leaves and stems. The differential activity of insecticides on adults suggests poor inherent potency of CAP as an adulticide and/or its limited systemicity in foliage. The distribution of insecticide in specific plant parts can be attributed to the different physicochemical properties of CAP and TMX. The field implications of this research on management of L. oryzophilus are discussed. © 2013 Society of Chemical Industry.

  16. Variations in heavy metal accumulation, growth and yield of rice plants grown at different sewage sludge amendment rates.

    PubMed

    Singh, R P; Agrawal, M

    2010-05-01

    Use of sewage sludge in agriculture is an alternative disposal technique for this waste. The present field study was conducted to assess the suitability of sewage sludge amendment in soil for rice (Oryza sativa L. cv. Pusa sugandha 3) by evaluating the heavy metal accumulation, growth, biomass and yield responses of plants grown at 0, 3, 4.5, 6, 9, 12 kgm(-2) sewage sludge amendment (SSA) rate. Sewage sludge amendment modified the physico-chemical properties of soil, thus increasing the availability of heavy metals in soil and consequently with higher accumulation in plant parts. Root length decreased, whereas shoot length, number of leaves, leaf area and total biomass increased significantly when grown under various SSA rates. Yield of rice increased by 60%, 111%, 125%, 134% and 137% at 3, 4.5, 6, 9 and 12 kgm(-2) SSA, respectively, as compared to those grown in unamended soil. Sewage sludge amendment rates above 4.5 kgm(-2) though increased the yield of rice, but caused risk of food chain contamination as concentrations of Ni and Cd in rice grains were found to be above the Indian safe limits (1.5 mgkg(-1)) of human consumption above 4.5 kgm(-2) SSA and of Pb (2.5 mgkg(-1)) above 6 kgm(-2) SSA. Since aboveground parts of the rice also showed higher concentration than the permissible levels of Ni, Cd and Pb at 4.5 kgm(-2) SSA rate, it cannot be used as fodder. The rice husk may be used as bioresource for energy production. Efforts should be made to treat the effluents from small scale industries before discharge into the sewerage system.

  17. Genetic analysis of inflorescence and plant height components in sorghum (Panicoidae) and comparative genetics with rice (Oryzoidae).

    PubMed

    Zhang, Dong; Kong, Wenqian; Robertson, Jon; Goff, Valorie H; Epps, Ethan; Kerr, Alexandra; Mills, Gabriel; Cromwell, Jay; Lugin, Yelena; Phillips, Christine; Paterson, Andrew H

    2015-04-19

    Domestication has played an important role in shaping characteristics of the inflorescence and plant height in cultivated cereals. Taking advantage of meta-analysis of QTLs, phylogenetic analyses in 502 diverse sorghum accessions, GWAS in a sorghum association panel (n = 354) and comparative data, we provide insight into the genetic basis of the domestication traits in sorghum and rice. We performed genome-wide association studies (GWAS) on 6 traits related to inflorescence morphology and 6 traits related to plant height in sorghum, comparing the genomic regions implicated in these traits by GWAS and QTL mapping, respectively. In a search for signatures of selection, we identify genomic regions that may contribute to sorghum domestication regarding plant height, flowering time and pericarp color. Comparative studies across taxa show functionally conserved 'hotspots' in sorghum and rice for awn presence and pericarp color that do not appear to reflect corresponding single genes but may indicate co-regulated clusters of genes. We also reveal homoeologous regions retaining similar functions for plant height and flowering time since genome duplication an estimated 70 million years ago or more in a common ancestor of cereals. In most such homoeologous QTL pairs, only one QTL interval exhibits strong selection signals in modern sorghum. Intersections among QTL, GWAS and comparative data advance knowledge of genetic determinants of inflorescence and plant height components in sorghum, and add new dimensions to comparisons between sorghum and rice.

  18. Development of a standard operating procedure (SOP) for the precise quantification of transgene expression levels in rice plants.

    PubMed

    James, Victoria A.; Worland, Barbara; Snape, John W.; Vain, Philippe

    2004-04-01

    Variation in transgene expression levels can result from uncontrolled differences in experimental protocols. It is important to quantify and eliminate this unwanted variation as much as possible in order to attain precision in transgenic studies. Large-scale transgenic studies could, by their design, generate additional variation. The influence of different plant growth, sampling and analysis strategies in generating spurious variation in transgene expression level quantification in rice plant populations was assessed. The use of multiple independent plant phenotypic analyses (enzymatic assays in this study) was identified as the major source of spurious variation (doubling or tripling the variation). The quantification of transgene expression levels was also found to be significantly influenced by plant age, the choice of leaf sampled and leaf size. All of these factors reduced the precision of molecular genetic studies and generated artefactual results in transgenic studies. Identification of the sources of extraneous variation allowed the development of a new standard operating procedure (SOP) for rice, designed to control spurious variation. SOP allowed the influence of differences in growth period and independent phenotypic analyses to be minimized. The coefficient of variation in transgene expression levels, between and within genetically identical rice plants, was reduced to approximately 10 to 15% using SOP. Adoption of quality assurance (QA) criteria such as SOP is key to improving the reproducibility of transgenic studies.

  19. [Competition and allelopathy of rice isogenic lines having similar genetic background but different plant morphology against weed].

    PubMed

    Yu, Liuqing; Lu, Yongliang; Zhou, Yongjun; Guo, Longbiao; Qian, Qian

    2005-04-01

    Zhefu 802 rice isogenic lines IG1, IG4, IG25 and IG26 have the same genetic background but different plant morphology. This paper studied their competition and allelopathy against barnyardgrass. The results showed that IG1 and IG4 had higher plant height, bigger tiller angle and less root vitality than IG25 and IG26, and provided 15% and 17% control of barnyardgrass plant dry weight, which were significantly higher than IG26. The competition ability of test rice isogenic lines against the weed was positively correlated with their plant height and tiller angle, but negatively correlated with their root vitality. The inhibition rate of the water extract of IG1 leaves on barnyardgrass root length was 77.6%, significantly higher than that of non-allelopathic material Xiushui 63, while the IG4 which has the similar plant morphology with IG1 didn't show any significant allelopathy. It seems that there were no correlations between allelopathy and morphological characters of rice under the same genetic background.

  20. Genetic analysis of inflorescence and plant height components in sorghum (Panicoidae) and comparative genetics with rice (Oryzoidae)

    SciTech Connect

    Zhang, Dong; Kong, Wenqian; Robertson, Jon; Goff, Valorie H; Epps, Ethan; Kerr, Alexandra; Mills, Gabriel; Cromwell, Jay; Lugin, Yelena; Phillips, Christine; Paterson, Andrew H

    2015-12-01

    Domestication has played an important role in shaping characteristics of the inflorescence and plant height in cultivated cereals. Taking advantage of meta-analysis of QTLs, phylogenetic analyses in 502 diverse sorghum accessions, GWAS in a sorghum association panel (n = 354) and comparative data, we provide insight into the genetic basis of the domestication traits in sorghum and rice. We performed genome-wide association studies (GWAS) on 6 traits related to inflorescence morphology and 6 traits related to plant height in sorghum, comparing the genomic regions implicated in these traits by GWAS and QTL mapping, respectively. In a search for signatures of selection, we identify genomic regions that may contribute to sorghum domestication regarding plant height, flowering time and pericarp color. Comparative studies across taxa show functionally conserved ‘hotspots’ in sorghum and rice for awn presence and pericarp color that do not appear to reflect corresponding single genes but may indicate co-regulated clusters of genes. We also reveal homoeologous regions retaining similar functions for plant height and flowering time since genome duplication an estimated 70 million years ago or more in a common ancestor of cereals. In most such homoeologous QTL pairs, only one QTL interval exhibits strong selection signals in modern sorghum. Intersections among QTL, GWAS and comparative data advance knowledge of genetic determinants of inflorescence and plant height components in sorghum, and add new dimensions to comparisons between sorghum and rice.

  1. Overexpression of the CC-type glutaredoxin, OsGRX6 affects hormone and nitrogen status in rice plants

    PubMed Central

    El-Kereamy, Ashraf; Bi, Yong-Mei; Mahmood, Kashif; Ranathunge, Kosala; Yaish, Mahmoud W.; Nambara, Eiji; Rothstein, Steven J.

    2015-01-01

    Glutaredoxins (GRXs) are small glutathione dependent oxidoreductases that belong to the Thioredoxin (TRX) superfamily and catalyze the reduction of disulfide bonds of their substrate proteins. Plant GRXs include three different groups based on the motif sequence, namely CPYC, CGFS, and CC-type proteins. The rice CC-type proteins, OsGRX6 was identified during the screening for genes whose expression changes depending on the level of available nitrate. Overexpression of OsGRX6 in rice displayed a semi-dwarf phenotype. The OsGRX6 overexpressors contain a higher nitrogen content than the wild type, indicating that OsGRX6 plays a role in homeostatic regulation of nitrogen use. Consistent with this, OsGRX6 overexpressors displayed delayed chlorophyll degradation and senescence compared to the wild type plants. To examine if the growth defect of these transgenic lines attribute to disturbed plant hormone actions, plant hormone levels were measured. The levels of two cytokinins (CKs), 2-isopentenyladenine and trans-zeatin, and gibberellin A1 (GA1) were increased in these lines. We also found that these transgenic lines were less sensitive to exogenously applied GA, suggesting that the increase in GA1 is a result of the feedback regulation. These data suggest that OsGRX6 affects hormone signaling and nitrogen status in rice plants. PMID:26579177

  2. Genetic analysis of inflorescence and plant height components in sorghum (Panicoidae) and comparative genetics with rice (Oryzoidae)

    DOE PAGES

    Zhang, Dong; Kong, Wenqian; Robertson, Jon; ...

    2015-12-01

    Domestication has played an important role in shaping characteristics of the inflorescence and plant height in cultivated cereals. Taking advantage of meta-analysis of QTLs, phylogenetic analyses in 502 diverse sorghum accessions, GWAS in a sorghum association panel (n = 354) and comparative data, we provide insight into the genetic basis of the domestication traits in sorghum and rice. We performed genome-wide association studies (GWAS) on 6 traits related to inflorescence morphology and 6 traits related to plant height in sorghum, comparing the genomic regions implicated in these traits by GWAS and QTL mapping, respectively. In a search for signatures ofmore » selection, we identify genomic regions that may contribute to sorghum domestication regarding plant height, flowering time and pericarp color. Comparative studies across taxa show functionally conserved ‘hotspots’ in sorghum and rice for awn presence and pericarp color that do not appear to reflect corresponding single genes but may indicate co-regulated clusters of genes. We also reveal homoeologous regions retaining similar functions for plant height and flowering time since genome duplication an estimated 70 million years ago or more in a common ancestor of cereals. In most such homoeologous QTL pairs, only one QTL interval exhibits strong selection signals in modern sorghum. Intersections among QTL, GWAS and comparative data advance knowledge of genetic determinants of inflorescence and plant height components in sorghum, and add new dimensions to comparisons between sorghum and rice.« less

  3. Calcium-dependent protein kinase OsCPK10 mediates both drought tolerance and blast disease resistance in rice plants.

    PubMed

    Bundó, Mireia; Coca, María

    2017-05-17

    Plant growth and productivity is negatively affected by different stresses. Most stresses trigger calcium signals that initiate acclimation responses in plants. The multigene family of plant calcium-dependent protein kinases (CPKs) functions in multiple stress responses by transducing calcium signals into phosphorylation events. This work reports that the OsCPK10 isoform positively mediates tolerance to different stresses in rice plants by enhancing their antioxidant capacity and protecting them from reactive oxygen species (ROS) damage, with the uncontrolled generation of ROS being a common feature of these stresses. Here, we show that the constitutive accumulation of an HA-tagged OsCPK10 full-length protein enhances the hydrogen peroxide detoxifying capacity of rice plants during desiccation. This is achived by modulating the accumulation of catalase proteins, which reduces the extent of lipid peroxidation and protects the integrity of cell membranes, resulting in drought tolerance. OsCPK10HA accumulation also confers blast disease resistance by interfering with fungal necrotrophic growth via a reduction in the accumulation of hydrogen peroxide. Furthermore, we show by bimolecular complementation assays that OsCPK10 is a plasma membrane protein that physically interacts in vivo with catalase A. OsCPK10 therefore appears to be a good molecular target to improve tolerance to abiotic stresses as well as to blast disease, which limit rice crop productivity. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  4. OsPIN5b modulates rice (Oryza sativa) plant architecture and yield by changing auxin homeostasis, transport and distribution.

    PubMed

    Lu, Guangwen; Coneva, Viktoriya; Casaretto, José A; Ying, Shan; Mahmood, Kashif; Liu, Fang; Nambara, Eiji; Bi, Yong-Mei; Rothstein, Steven J

    2015-09-01

    Plant architecture attributes such as tillering, plant height and panicle size are important agronomic traits that determine rice (Oryza sativa) productivity. Here, we report that altered auxin content, transport and distribution affect these traits, and hence rice yield. Overexpression of the auxin efflux carrier-like gene OsPIN5b causes pleiotropic effects, mainly reducing plant height, leaf and tiller number, shoot and root biomass, seed-setting rate, panicle length and yield parameters. Conversely, reduced expression of OsPIN5b results in higher tiller number, more vigorous root system, longer panicles and increased yield. We show that OsPIN5b is an endoplasmic reticulum (ER) -localized protein that participates in auxin homeostasis, transport and distribution in vivo. This work describes an example of an auxin-related gene where modulating its expression can simultaneously improve plant architecture and yield potential in rice, and reveals an important effect of hormonal signaling on these traits. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

  5. Influence of sulfur on the accumulation of mercury in rice plant (Oryza sativa L.) growing in mercury contaminated soils.

    PubMed

    Li, Yunyun; Zhao, Jiating; Guo, Jingxia; Liu, Mengjiao; Xu, Qinlei; Li, Hong; Li, Yu-Feng; Zheng, Lei; Zhang, Zhiyong; Gao, Yuxi

    2017-09-01

    Sulfur (S) is an essential element for plant growth and its biogeochemical cycling is strongly linked to the species of heavy metals in soil. In this work, the effects of S (sulfate and elemental sulfur) treatment on the accumulation, distribution and chemical forms of Hg in rice growing in Hg contaminated soil were investigated. It was found that S could promote the formation of iron plaque on the root surface and decrease total mercury (T-Hg) and methylmercury (MeHg) accumulation in rice grains, straw, and roots. Hg in the root was dominated in the form of RS-Hg-SR. Sulfate treatment increased the percentage of RS-Hg-SR to T-Hg in the rice root and changed the Hg species in soil. The dominant Hg species (70%) in soil was organic substance bound fractions. Sulfur treatment decreased Hg motility in the rhizosphere soils by promoting the conversion of RS-Hg-SR to HgS. This study is significant since it suggests that low dose sulfur treatment in Hg-containing water irrigated soil can decrease both T-Hg and MeHg accumulation in rice via inactivating Hg in the soil and promoting the formation of iron plaque in rice root, which may reduce health risk for people consuming those crops. Copyright © 2017. Published by Elsevier Ltd.

  6. Evaluation of rhizosphere, rhizoplane and phyllosphere bacteria and fungi isolated from rice in Kenya for plant growth promoters.

    PubMed

    Mwajita, Mwashasha Rashid; Murage, Hunja; Tani, Akio; Kahangi, Esther M

    2013-01-01

    Rice (Oryza sativa L.) is the most important staple food crop in many developing countries, and is ranked third in Kenya after maize and wheat. Continuous cropping without replenishing soil nutrients is a major problem in Kenya resulting to declining soil fertility. The use of chemical fertilizers to avert the problem of low soil fertility is currently limited due to rising costs and environmental concerns. Many soil micro-organisms are able to solubilize the unavailable phosphorus, increase uptake of nitrogen and also synthesize growth promoting hormones including auxin. The aim of this study was to isolate and characterize phyllosphere, rhizoplane and rhizosphere micro-organisms from Kenyan rice with growth promoting habits. In this study whole plant rice samples were collected from different rice growing regions of Kenya. 76.2%, over 80% and 38.5% of the bacterial isolates were positive for phosphate solubilization, nitrogenase activity and IAA production whereas 17.5% and 5% of the fungal isolates were positive for phosphate solubilization and IAA production respectively. Hence these micro-organisms have potential for utilization as bio-fertilizers in rice production.

  7. Toxic tetrapyrrole accumulation in protoporphyrinogen IX oxidase-overexpressing transgenic rice plants.

    PubMed

    Jung, Sunyo; Lee, Hye-Jung; Lee, Yonghyuk; Kang, Kiyoon; Kim, Young Soon; Grimm, Bernhard; Back, Kyoungwhan

    2008-07-01

    We generated transgenic rice plants (Oryza sativa cv. Dongjin) over-expressing human protoporphyrinogen IX oxidase (PPO) with the aim to increase mitochondrial PPO activity and confer herbicide resistance (Lee et al., Pestic Biochem Physiol 80:65-74, 2004). The transgenic plants showed during further leaf development the formation of severe necrotic spots and growth retardation. Several experiments were performed to examine the reasons for the formation of necrotic leaf lesions. Human PPO is normally located in mitochondria. An in vitro organellar import experiment revealed translocation of human PPO into pea chloroplasts, but not into mitochondria. Using a specific antibody raised against human PPO confirmed its plastidic localisation. The heme and chlorophyll contents were lower in necrotic leaves than wild-type leaves. Interestingly, mature and necrotic leaves of 12-week-old transgenic plants contained up to 14- and 24-fold more protoporphyrin IX, respectively, than mature wild-type leaves. Enhanced levels of Mg-Protoporphyrin IX, Mg-Protoporphyrin IX monomethyl ester and protochlorophyllide were concurrently observed in transgenic plants relative to wild type. Accumulated porphyrins and Mg-porphyrins likely act as photosensitizers and cause high formation of the reactive oxygen species. These high levels of tetrapyrrole intermediates correlated with increased rates of 5-aminolevulinic acid synthesis in transgenic plants. Tetrapyrrole-induced photooxidation was confirmed by increased lipid peroxidation and subsequent cell death. The transgenic phenotype is the consequence of a highly modified tetrapyrrole metabolism due to additional expression of human PPO. A possible regulatory role of PPO in graminaceous seedlings is discussed.

  8. Dominance and epistasis are the main contributors to heterosis for plant height in rice.

    PubMed

    Shen, Guojing; Zhan, Wei; Chen, Huaxia; Xing, Yongzhong

    2014-02-01

    The genetic basis of heterosis has been debated for over 100 years regarding whether dominance or overdominance plays a more important role and the answer is still unclear. The major limitation to assess the contribution of a single locus has been the genetic background noise due to genome-wide segregation of multiple loci. To dissect the genetic basis of heterosis at a single locus for plant height, we developed a set of 202 chromosome segment substitution lines (CSSLs) of an elite hybrid, Shanyou 63, the best hybrid rice in China in the 1990s. Fifteen CSSLs had varied plant heights within lines. A total of 15 partial dominance QTLs for plant height were detected in these 15 CSSL-F2 populations. All hybrids between the 15 CSSLs and the recurrent parent, Zhenshan 97, were shorter than the corresponding CSSLs, but taller than Zhenshan 97. These indicated that these 15 QTLs were also heterosis loci (HLs) contributed to heterosis acted in dominance. Each HL contributed from -7.4 to 14.4% of midparent heterosis. Additive by additive (AA) and additive by dominance (AD) interactions were detected in the Tetra-F2 population segregating at the four major QTLs with the largest effects on plant height. Substantial negative AA effects were detected between two major QTLs QPH7.2 and QPH7.3, which increased heterosis in the study. Thus we concluded that dominance and epistasis are the major genetic basis of plant height heterosis, which could explain the better parent heterosis in Shanyou 63.

  9. Dental health in workers previously exposed to mercury vapour at a chloralkali plant.

    PubMed Central

    Holland, R I; Ellingsen, D G; Olstad, M L; Kjuus, H

    1994-01-01

    OBJECTIVES--The dental health of 73 workers previously exposed to mercury vapour at a chloralkali plant was studied and compared with that of 51 non-exposed referents. METHODS--A record of oral, periodontal, gingival and mucosal conditions, including teeth, restorations, prostheses, and oral hygiene, was established during a 30 min examination. The participants' periodontal conditions were assessed according to the community periodontal index of treatment needs (CPITN). The results with the CPITN index were also compared with previously published data for another similar population. RESULTS--There was no significant difference between the exposed workers and the referents with respect to the number of remaining teeth, amount of amalgam restorations, crowns, bridges, or endodontically treated teeth. The oral hygiene among the exposed workers was significantly better than among the referents, but the periodontal health conditions did not significantly differ between the two groups, nor from those of another Norwegian population. DISCUSSION--The present results seem to contradict previous reports claiming tooth loss as a possible result of exposure to mercury vapour. PMID:8000488

  10. Evaluation of Host-Plant Resistance of Selected Rice Genotypes to the Rice Water Weevil (Coleoptera: Curculionidae).

    PubMed

    Vyavhare, Suhas S; Gealy, David R; Way, Michael O; Tabien, Rodante E; Pearson, Rebecca A

    2016-08-30

    The rice water weevil, Lissorhoptrus oryzophilus Kuschel, is the most important insect pest of rice in the United States. Management of L. oryzophilus mainly depends upon the use of insecticides due to the lack of effective alternative management tactics. A 3-yr field study was conducted to determine if difference exists among rice genotypes and cultivars of inbred tropical japonica subspecies commercially grown in the southern United States [Cocodrie (PI 606331), CL171, and CL151 (PI 654463)] and the germplasm lines of indica subspecies adapted to tropical climates of Asia [WC 4644 (PI 312777), TNI (PI 495830), Rondo (PI 615022), 4612 (PI 615039), TeQing (PI 536047), and 4593 (PI 615031)] for resistance to L. oryzophilus Experiments were established as a split-plot design with cultivars as main plots and insecticide treatment as subplots. No significant differences were observed in number of L. oryzophilus larvae recovered across cultivars and genotypes, indicating no significant variation in their preference to L. oryzophilus oviposition. Insecticide treatment had a significant impact on L. oryzophilus larval density. However, grain yield did not vary significantly between treated and untreated plots for any of the cultivars and genotypes. The amount of yield loss in response to L. oryzophilus infestation did not vary significantly across genotypes and cultivars, indicating no variation among these genotypes for resistance to L. oryzophilus.

  11. Evaluation of Host-Plant Resistance of Selected Rice Genotypes to the Rice Water Weevil (Coleoptera: Curculionidae).

    PubMed

    Vyavhare, Suhas S; Gealy, David R; Way, Michael O; Tabien, Rodante E; Pearson, Rebecca A

    2016-12-01

    The rice water weevil, Lissorhoptrus oryzophilus Kuschel, is the most important insect pest of rice in the United States. Management of L. oryzophilus mainly depends upon the use of insecticides due to the lack of effective alternative management tactics. A 3-yr field study was conducted to determine if difference exists among rice genotypes and cultivars of inbred tropical japonica subspecies commercially grown in the southern United States [Cocodrie (PI 606331), CL171, and CL151 (PI 654463)] and the germplasm lines of indica subspecies adapted to tropical climates of Asia [WC 4644 (PI 312777), TNI (PI 495830), Rondo (PI 615022), 4612 (PI 615039), TeQing (PI 536047), and 4593 (PI 615031)] for resistance to L. oryzophilus Experiments were established as a split-plot design with cultivars as main plots and insecticide treatment as subplots. No significant differences were observed in number of L. oryzophilus larvae recovered across cultivars and genotypes, indicating no significant variation in their preference to L. oryzophilus oviposition. Insecticide treatment had a significant impact on L. oryzophilus larval density. However, grain yield did not vary significantly between treated and untreated plots for any of the cultivars and genotypes. The amount of yield loss in response to L. oryzophilus infestation did not vary significantly across genotypes and cultivars, indicating no variation among these genotypes for resistance to L. oryzophilus.

  12. Bioaccumulation and tolerance characteristics of a submerged plant (Ceratophyllum demersum L.) exposed to toxic metal lead.

    PubMed

    Chen, Min; Zhang, Ling-Lei; Li, Jia; He, Xiao-Jia; Cai, Jun-Chi

    2015-12-01

    A hydroponic study was conducted to investigate the lead bioaccumulation and tolerance characteristics of Ceratophyllum demersum L. exposed to various lead concentrations (5-80 μM) for 7, 14 or 21 days. Lead accumulation increased with increasing concentrations of metal in the solution, to a maximum accumulation of 4016.4 mg kg(-1) dw. Unexpectedly, the release of accumulated lead from the plants into solution was observed for all experimental groups except those exposed to 5 μM. Both the biomass and protein content of the plants responded significantly to lead stress. Malondialdehyde (MDA) levels increased substantially at lead concentrations below 20 μM, further indicating that this metal is toxic to the plants. To reveal the mechanism underlying the defense against lead stress, plants were also assayed for the activities of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD), as well as other relevant enzymes such as phenylalanine ammonia-lyase (PAL) and polyphenol oxidase (PPO). The activities of both SOD and CAT increased at lower lead concentrations and with shorter exposure times, followed by a decline, but the activities of POD and its isoenzymes continued to increase under all conditions. Moreover, increases in the activities of PAL and PPO were observed only for the 14-day treatment, and these two enzymes were not sensitive to lead concentration. These results suggest that C. demersum exhibits strong tolerance within a specific concentration range of lead in solution; according to regression analysis, 40 μM is suggested to be this plant's tolerance threshold for lead in water. Furthermore, the malfunction of this tolerance mechanism might accelerate the metal-release process. These attributes are likely to be beneficial for utilizing C. demersum in phytoremediation applications.

  13. Iron isotope fingerprints of redox and biogeochemical cycling in the soil-water-rice plant system of a paddy field.

    PubMed

    Garnier, J; Garnier, J-M; Vieira, C L; Akerman, A; Chmeleff, J; Ruiz, R I; Poitrasson, F

    2017-01-01

    The iron isotope composition was used to investigate dissimilatory iron reduction (DIR) processes in an iron-rich waterlogged paddy soil, the iron uptake strategies of plants and its translocation in the different parts of the rice plant along its growth. Fe concentration and isotope composition (δ(56)Fe) in irrigation water, precipitates from irrigation water, soil, pore water solution at different depths under the surface water, iron plaque on rice roots, rice roots, stems, leaves and grains were measured. Over the 8.5-10cm of the vertical profiles investigated, the iron pore water concentration (0.01 to 24.3mg·l(-1)) and δ(56)Fe (-0.80 to -3.40‰) varied over a large range. The significant linear co-variation between Ln[Fe] and δ(56)Fe suggests an apparent Rayleigh-type behavior of the DIR processes. An average net fractionation factor between the pore water and the soil substrate of Δ(56)Fe≈-1.15‰ was obtained, taking the average of all the δ(56)Fe values weighted by the amount of Fe for each sample. These results provide a robust field study confirmation of the conceptual model of Crosby et al. (2005, 2007) for interpreting the iron isotope fractionation observed during DIR, established from a series of laboratories experiments. In addition, the strong enrichment of heavy Fe isotope measured in the root relative to the soil solution suggest that the iron uptake by roots is more likely supplied by iron from plaque and not from the plant-available iron in the pore water. Opposite to what was previously observed for plants following strategy II for iron uptake from soils, an iron isotope fractionation factor of -0.9‰ was found from the roots to the rice grains, pointing to isotope fractionation during rice plant growth. All these features highlight the insights iron isotope composition provides into the biogeochemical Fe cycling in the soil-water-rice plant systems studied in nature.

  14. Modulation of plant defense responses to herbivores by simultaneous recognition of different herbivore-associated elicitors in rice

    PubMed Central

    Shinya, Tomonori; Hojo, Yuko; Desaki, Yoshitake; Christeller, John T.; Okada, Kazunori; Shibuya, Naoto; Galis, Ivan

    2016-01-01

    Induced plant defense responses against insect herbivores are triggered by wounding and/or perception of herbivore elicitors from their oral secretions (OS) and/or saliva. In this study, we analyzed OS isolated from two rice chewing herbivores, Mythimna loreyi and Parnara guttata. Both types of crude OS had substantial elicitor activity in rice cell system that allowed rapid detection of early and late defense responses, i.e. accumulation of reactive oxygen species (ROS) and defense secondary metabolites, respectively. While the OS from M. loreyi contained large amounts of previously reported insect elicitors, fatty acid-amino acid conjugates (FACs), the elicitor-active P. guttata’s OS contained no detectable FACs. Subsequently, elicitor activity associated with the high molecular mass fraction in OS of both herbivores was identified, and shown to promote ROS and metabolite accumulations in rice cells. Notably, the application of N-linolenoyl-Gln (FAC) alone had only negligible elicitor activity in rice cells; however, the activity of isolated elicitor fraction was substantially promoted by this FAC. Our results reveal that plants integrate various independent signals associated with their insect attackers to modulate their defense responses and reach maximal fitness in nature. PMID:27581373

  15. Modulation of plant defense responses to herbivores by simultaneous recognition of different herbivore-associated elicitors in rice.

    PubMed

    Shinya, Tomonori; Hojo, Yuko; Desaki, Yoshitake; Christeller, John T; Okada, Kazunori; Shibuya, Naoto; Galis, Ivan

    2016-09-01

    Induced plant defense responses against insect herbivores are triggered by wounding and/or perception of herbivore elicitors from their oral secretions (OS) and/or saliva. In this study, we analyzed OS isolated from two rice chewing herbivores, Mythimna loreyi and Parnara guttata. Both types of crude OS had substantial elicitor activity in rice cell system that allowed rapid detection of early and late defense responses, i.e. accumulation of reactive oxygen species (ROS) and defense secondary metabolites, respectively. While the OS from M. loreyi contained large amounts of previously reported insect elicitors, fatty acid-amino acid conjugates (FACs), the elicitor-active P. guttata's OS contained no detectable FACs. Subsequently, elicitor activity associated with the high molecular mass fraction in OS of both herbivores was identified, and shown to promote ROS and metabolite accumulations in rice cells. Notably, the application of N-linolenoyl-Gln (FAC) alone had only negligible elicitor activity in rice cells; however, the activity of isolated elicitor fraction was substantially promoted by this FAC. Our results reveal that plants integrate various independent signals associated with their insect attackers to modulate their defense responses and reach maximal fitness in nature.

  16. Genome-wide binding analysis of the transcription activator ideal plant architecture1 reveals a complex network regulating rice plant architecture.

    PubMed

    Lu, Zefu; Yu, Hong; Xiong, Guosheng; Wang, Jing; Jiao, Yongqing; Liu, Guifu; Jing, Yanhui; Meng, Xiangbing; Hu, Xingming; Qian, Qian; Fu, Xiangdong; Wang, Yonghong; Li, Jiayang

    2013-10-01

    Ideal plant architecture1 (IPA1) is critical in regulating rice (Oryza sativa) plant architecture and substantially enhances grain yield. To elucidate its molecular basis, we first confirmed IPA1 as a functional transcription activator and then identified 1067 and 2185 genes associated with IPA1 binding sites in shoot apices and young panicles, respectively, through chromatin immunoprecipitation sequencing assays. The Squamosa promoter binding protein-box direct binding core motif GTAC was highly enriched in IPA1 binding peaks; interestingly, a previously uncharacterized indirect binding motif TGGGCC/T was found to be significantly enriched through the interaction of IPA1 with proliferating cell nuclear antigen promoter binding factor1 or promoter binding factor2. Genome-wide expression profiling by RNA sequencing revealed IPA1 roles in diverse pathways. Moreover, our results demonstrated that IPA1 could directly bind to the promoter of rice teosinte branched1, a negative regulator of tiller bud outgrowth, to suppress rice tillering, and directly and positively regulate dense and erect panicle1, an important gene regulating panicle architecture, to influence plant height and panicle length. The elucidation of target genes of IPA1 genome-wide will contribute to understanding the molecular mechanisms underlying plant architecture and to facilitating the breeding of elite varieties with ideal plant architecture.

  17. Genome-Wide Binding Analysis of the Transcription Activator IDEAL PLANT ARCHITECTURE1 Reveals a Complex Network Regulating Rice Plant Architecture[W

    PubMed Central

    Lu, Zefu; Yu, Hong; Xiong, Guosheng; Wang, Jing; Jiao, Yongqing; Liu, Guifu; Jing, Yanhui; Meng, Xiangbing; Hu, Xingming; Qian, Qian; Fu, Xiangdong; Wang, Yonghong; Li, Jiayang

    2013-01-01

    IDEAL PLANT ARCHITECTURE1 (IPA1) is critical in regulating rice (Oryza sativa) plant architecture and substantially enhances grain yield. To elucidate its molecular basis, we first confirmed IPA1 as a functional transcription activator and then identified 1067 and 2185 genes associated with IPA1 binding sites in shoot apices and young panicles, respectively, through chromatin immunoprecipitation sequencing assays. The SQUAMOSA PROMOTER BINDING PROTEIN-box direct binding core motif GTAC was highly enriched in IPA1 binding peaks; interestingly, a previously uncharacterized indirect binding motif TGGGCC/T was found to be significantly enriched through the interaction of IPA1 with proliferating cell nuclear antigen PROMOTER BINDING FACTOR1 or PROMOTER BINDING FACTOR2. Genome-wide expression profiling by RNA sequencing revealed IPA1 roles in diverse pathways. Moreover, our results demonstrated that IPA1 could directly bind to the promoter of rice TEOSINTE BRANCHED1, a negative regulator of tiller bud outgrowth, to suppress rice tillering, and directly and positively regulate DENSE AND ERECT PANICLE1, an important gene regulating panicle architecture, to influence plant height and panicle length. The elucidation of target genes of IPA1 genome-wide will contribute to understanding the molecular mechanisms underlying plant architecture and to facilitating the breeding of elite varieties with ideal plant architecture. PMID:24170127

  18. 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.

  19. Differential distribution of proteins expressed in companion cells in the sieve element-companion cell complex of rice plants.

    PubMed

    Fukuda, Akari; Fujimaki, Syu; Mori, Tomoko; Suzui, Nobuo; Ishiyama, Keiki; Hayakawa, Toshihiko; Yamaya, Tomoyuki; Fujiwara, Toru; Yoneyama, Tadakatsu; Hayashi, Hiroaki

    2005-11-01

    Sieve tubes are comprised of sieve elements, enucleated cells that are incapable of RNA and protein synthesis. The proteins in sieve elements are supplied from the neighboring companion cells through plasmodesmata. In rice plants, it was unclear whether or not all proteins produced in companion cells had the same distribution pattern in the sieve element-companion cell complex. In this study, the distribution pattern of four proteins, beta-glucuronidase (GUS), green fluorescent protein (GFP), thioredoxin h (TRXh) and glutathione S-transferase (GST) were analyzed. The foreign proteins GUS and GFP were expressed in transgenic rice plants under the control of the TRXh gene promoter (PTRXh), a companion cell-specific promoter. Analysis of leaf cross-sections of PTRXh-GUS and PTRXh-GFP plants indicated high accumulation of GUS and GFP, respectively, in companion cells rather than in sieve elements. GUS and GFP were also detected in phloem sap collected from leaf sheaths of the transgenic rice plants, suggesting these proteins could enter sieve elements. Relative amounts of GFP and endogenous phloem proteins, TRXh and GST, in phloem sap and total leaf extracts were compared. Compared to TRXh and GST, GFP content was higher in total leaf extracts, but lower in phloem sap, suggesting that GFP accumulated mainly in companion cells rather than in sieve elements. On the other hand, TRXh and GST appeared to accumulate in sieve elements rather than in companion cells. These results indicate the evidence for differential distribution of proteins between sieve elements and companion cells in rice plants.

  20. A Study on the Tritium Behavior in the Rice Plant after a Short-Term Exposure of HTO

    SciTech Connect

    Yook, D-S.; Lee, K. J.; Choi, Y-H.

    2002-02-26

    In many Asian countries including Korea, rice is a very important food crop. Its grain is consumed by humans and its straw is used to feed animals. In Korea, there are four CANDU type reactors that release relatively large amounts of tritium into the environment. Since 1997, KAERI (Korea Atomic Energy Research Institute) has carried out the experimental studies to obtain domestic data on various parameters concerning the direct contamination of plant. In this study, the behavior of tritium in the rice plant is predicted and compared with the measurement performed at KAERI. Using the conceptual model of the soil-plant-atmosphere tritiated water transport system which was suggested by Charles E. Murphy, tritium concentrations in the soil and in leaves to time were derived. If the effect of tritium concentration in the soil is considered, the tritium concentration in leaves is described as a double exponential model. On the other hand if the tritium concentration in the soil is disregarded, the tritium concentration in leaves is described by a single exponential term as other models (e.g. Belot's or STAR-H3 model). Also concentration of organically bound tritium in the seed is predicted and compared with measurements. The results can be used to predict the tritium concentration in the rice plant at a field around the site and the ingestion dose following the release of tritium to the environment.

  1. Arabidopsis thaliana: A Model Host Plant to Study Plant–Pathogen Interaction Using Rice False Smut Isolates of Ustilaginoidea virens

    PubMed Central

    Andargie, Mebeaselassie; Li, Jianxiong

    2016-01-01

    Rice false smut fungus which is a biotrophic fungal pathogen causes an important rice disease and brings a severe damage where rice is cultivated. We established a new fungal-plant pathosystem where Ustilaginoidea virens was able to interact compatibly with the model plant Arabidopsis thaliana. Disease symptoms were apparent on the leaves of the plants after 6 days of post inoculation in the form of chlorosis. Cytological studies showed that U. virens caused a heavy infestation inside the cells of the chlorotic tissues. Development and colonization of aerial mycelia in association with floral organ, particularly on anther and stigma of the flowers after 3 weeks of post inoculation was evident which finally caused infection on the developing seeds and pod tissues. The fungus adopts a uniquely biotrophic infection strategy in roots and spreads without causing a loss of host cell viability. We have also demonstrated that U. virens isolates infect Arabidopsis and the plant subsequently activates different defense response mechanisms which are witnessed by the expression of pathogenesis-related genes, PR-1, PR-2, PR-5, PDF1.1, and PDF1.2. The established A. thaliana–U. virens pathosystem will now permit various follow-up molecular genetics and gene expression experiments to be performed to identify the defense signals and responses that restrict fungal hyphae colonization in planta and also provide initial evidence for tissue-adapted fungal infection strategies. PMID:26941759

  2. P1-independent replication and local movement of Rice yellow mottle virus in host and non-host plant species.

    PubMed

    Nummert, Grete; Sõmera, Merike; Uffert, Gabriela; Abner, Erik; Truve, Erkki

    2017-02-01

    Sobemovirus P1 protein, characterized previously as a suppressor of posttranscriptional gene silencing, is required for systemic virus spread and infection in plants. Mutations in the ORF1 initiation codon do not affect viral replication indicating P1 is not necessary for this process. Wild type, recombinant and P1 deletion mutants of Cocksfoot mottle virus and Rice yellow mottle virus were used to infect oat, rice, wheat, barley, Arabidopsis thaliana and Nicotiana benthamiana plants. Wild type RYMV, RYMV without P1 and RYMV with CfMV P1 were detected in inoculated leaves of all tested plant species. We found that RYMV does not need P1 for replication and for local movement neither in host nor non-host species tested in this study. However, it is crucial for successful systemic spread of the virus in its host plant rice. Moreover, adding CfMV P1 into RYMV genome did not help it to overcome restriction to the inoculated leaf. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Silicon isotope fractionation in rice and cucumber plants over a life cycle: Laboratory studies at different external silicon concentrations

    NASA Astrophysics Data System (ADS)

    Sun, Yan; Wu, Lianghuan; Li, Xiaoyan; Sun, Li; Gao, Jianfei; Ding, Tiping

    2016-11-01

    Understanding the variations of silicon isotopes in terrestrial higher plants can be helpful toward elucidating the global biogeochemical silicon cycle. We studied silicon isotope fractionation in rice and cucumber plants over their entire life cycles. These two different silicon-absorbing plants were grown hydroponically at different external silicon concentrations. The ranges of δ30Si values in rice were -1.89‰ to 1.69‰, -1.81‰ to 1.96‰, and -2.08‰ to 2.02‰ at 0.17 mM, 1.70 mM, and 8.50 mM silicon concentrations, respectively. The ranges of δ30Si values in cucumber were -1.38‰ to 1.21‰, -1.33‰ to 1.26‰, and -1.62‰ to 1.40‰ at 0.085 mM, 0.17 mM, and 1.70 mM external silicon concentrations, respectively. A general increasing trend in δ30Si values from lower to upper plant parts reflected the preferential incorporation of lighter silicon isotopes from transpired water to biogenic opal. Furthermore, the active uptake mechanism regulated by several transporters might have also played an important role in the preferential transport of heavy silicon isotopes into aboveground plant parts. This suggested that silicon isotope fractionation in both rice and cucumber was a Rayleigh-like process. The data on δ30Si values for the whole plants and nutrient solutions indicated that biologically mediated silicon isotope fractionation occurred during silicon uptake by roots. At lower external silicon concentrations, heavy silicon isotopes entered plants more readily than light silicon isotopes. Conversely, at higher external silicon concentrations, light silicon isotopes entered plants more readily than heavy silicon isotopes.

  4. Effect of photoperiodic pretreatments on symptom development in plants exposed to ozone

    SciTech Connect

    Godish, T.

    1980-01-01

    Results presented in this report on the effects of photoperiodic pretreatment on ozone sensitivity of plants are significantly different from the lone previous report on this subject. Juhren et al (5) studied the effects of photoperiodic pretreatments on sensitivity of pinto beans exposed to oxidants (presumably ozone). They reported that pinto bean plants were most sensitive to oxidants under short photoperiods (8 hours) and least sensitive to long photoperiods (16 hours). In studies of tomato and peas presented in this report, minimum sensitivity for tomato was observed under the 8 hour pretreatment; for peas minimum sensitivity was observed for the 8 and 10 hour pretreatments. Maximum sensitivity for tomato was observed for the 12-hour photoperiodic pretreatment; peas showed maximum sensitivity under the 14-hour photoperiod. 7 references, 1 table.

  5. Rice ( Oryza) hemoglobins

    PubMed Central

    Arredondo-Peter, Raúl; Moran, Jose F.; Sarath, Gautam

    2014-01-01

    Hemoglobins (Hbs) corresponding to non-symbiotic (nsHb) and truncated (tHb) Hbs have been identified in rice ( Oryza). This review discusses the major findings from the current studies on rice Hbs. At the molecular level, a family of the nshb genes, consisting of hb1, hb2, hb3, hb4 and hb5, and a single copy of the thb gene exist in Oryza sativa var. indica and O. sativa var. japonica, Hb transcripts coexist in rice organs and Hb polypeptides exist in rice embryonic and vegetative organs and in the cytoplasm of differentiating cells. At the structural level, the crystal structure of rice Hb1 has been elucidated, and the structures of the other rice Hbs have been modeled. Kinetic analysis indicated that rice Hb1 and 2, and possibly rice Hb3 and 4, exhibit a very high affinity for O 2, whereas rice Hb5 and tHb possibly exhibit a low to moderate affinity for O 2. Based on the accumulated information on the properties of rice Hbs and data from the analysis of other plant and non-plant Hbs, it is likely that Hbs play a variety of roles in rice organs, including O 2-transport, O 2-sensing, NO-scavenging and redox-signaling. From an evolutionary perspective, an outline for the evolution of rice Hbs is available. Rice nshb and thb genes vertically evolved through different lineages, rice nsHbs evolved into clade I and clade II lineages and rice nshbs and thbs evolved under the effect of neutral selection. This review also reveals lacunae in our ability to completely understand rice Hbs. Primary lacunae are the absence of experimental information about the precise functions of rice Hbs, the properties of modeled rice Hbs and the cis-elements and trans-acting factors that regulate the expression of rice hb genes, and the partial understanding of the evolution of rice Hbs. PMID:25653837

  6. Rice ( Oryza) hemoglobins.

    PubMed

    Arredondo-Peter, Raúl; Moran, Jose F; Sarath, Gautam

    2014-01-01

    Hemoglobins (Hbs) corresponding to non-symbiotic (nsHb) and truncated (tHb) Hbs have been identified in rice ( Oryza). This review discusses the major findings from the current studies on rice Hbs. At the molecular level, a family of the nshb genes, consisting of hb1, hb2, hb3, hb4 and hb5, and a single copy of the thb gene exist in Oryza sativa var. indica and O. sativa var. japonica, Hb transcripts coexist in rice organs and Hb polypeptides exist in rice embryonic and vegetative organs and in the cytoplasm of differentiating cells. At the structural level, the crystal structure of rice Hb1 has been elucidated, and the structures of the other rice Hbs have been modeled. Kinetic analysis indicated that rice Hb1 and 2, and possibly rice Hb3 and 4, exhibit a very high affinity for O 2, whereas rice Hb5 and tHb possibly exhibit a low to moderate affinity for O 2. Based on the accumulated information on the properties of rice Hbs and data from the analysis of other plant and non-plant Hbs, it is likely that Hbs play a variety of roles in rice organs, including O 2-transport, O 2-sensing, NO-scavenging and redox-signaling. From an evolutionary perspective, an outline for the evolution of rice Hbs is available. Rice nshb and thb genes vertically evolved through different lineages, rice nsHbs evolved into clade I and clade II lineages and rice nshbs and thbs evolved under the effect of neutral selection. This review also reveals lacunae in our ability to completely understand rice Hbs. Primary lacunae are the absence of experimental information about the precise functions of rice Hbs, the properties of modeled rice Hbs and the cis-elements and trans-acting factors that regulate the expression of rice hb genes, and the partial understanding of the evolution of rice Hbs.

  7. Integrative Analysis of the microRNAome and Transcriptome Illuminates the Response of Susceptible Rice Plants to Rice Stripe Virus.

    PubMed

    Yang, Jian; Zhang, Fen; Li, Jing; Chen, Jian-Ping; Zhang, Heng-Mu

    2016-01-01

    Rice stripe virus (RSV) is one of the most serious rice viruses in East Asia. To investigate how rice responds to RSV infection, we integrated miRNA expression with parallel mRNA transcription profiling by deep sequencing. A total of 570 miRNAs were identified of which 69 miRNAs (56 up-regulated and 13 down-regulated) were significantly modified by RSV infection. Digital gene expression (DGE) analysis showed that 1274 mRNAs (431 up-regulated and 843 down-regulated genes) were differentially expressed as a result of RSV infection. The differential expression of selected miRNAs and mRNAs was confirmed by qRT-PCR. Gene ontology (GO) and pathway enrichment analysis showed that a complex set of miRNA and mRNA networks were selectively regulated by RSV infection. In particular, 63 differentially expressed miRNAs were found to be significantly and negatively correlated with 160 target mRNAs. Interestingly, 22 up-regulated miRNAs were negatively correlated with 24 down-regulated mRNAs encoding disease resistance-related proteins, indicating that the host defense responses were selectively suppressed by RSV infection. The suppression of both osa-miR1423-5p- and osa-miR1870-5p-mediated resistance pathways was further confirmed by qRT-PCR. Chloroplast functions were also targeted by RSV, especially the zeaxanthin cycle, which would affect the stability of thylakoid membranes and the biosynthesis of ABA. All these modifications may contribute to viral symptom development and provide new insights into the pathogenicity mechanisms of RSV.

  8. Integrative Analysis of the microRNAome and Transcriptome Illuminates the Response of Susceptible Rice Plants to Rice Stripe Virus

    PubMed Central

    Yang, Jian; Zhang, Fen; Li, Jing; Chen, Jian-Ping; Zhang, Heng-Mu

    2016-01-01

    Rice stripe virus (RSV) is one of the most serious rice viruses in East Asia. To investigate how rice responds to RSV infection, we integrated miRNA expression with parallel mRNA transcription profiling by deep sequencing. A total of 570 miRNAs were identified of which 69 miRNAs (56 up-regulated and 13 down-regulated) were significantly modified by RSV infection. Digital gene expression (DGE) analysis showed that 1274 mRNAs (431 up-regulated and 843 down-regulated genes) were differentially expressed as a result of RSV infection. The differential expression of selected miRNAs and mRNAs was confirmed by qRT-PCR. Gene ontology (GO) and pathway enrichment analysis showed that a complex set of miRNA and mRNA networks were selectively regulated by RSV infection. In particular, 63 differentially expressed miRNAs were found to be significantly and negatively correlated with 160 target mRNAs. Interestingly, 22 up-regulated miRNAs were negatively correlated with 24 down-regulated mRNAs encoding disease resistance-related proteins, indicating that the host defense responses were selectively suppressed by RSV infection. The suppression of both osa-miR1423-5p- and osa-miR1870-5p-mediated resistance pathways was further confirmed by qRT-PCR. Chloroplast functions were also targeted by RSV, especially the zeaxanthin cycle, which would affect the stability of thylakoid membranes and the biosynthesis of ABA. All these modifications may contribute to viral symptom development and provide new insights into the pathogenicity mechanisms of RSV. PMID:26799317

  9. Health risk assessment of workers exposed to metals from an aluminium production plant.

    PubMed

    Buranatrevedh, Surasak

    2010-12-01

    Foundry is an industry involved various kinds of metals and chemicals. Workers who work in foundry industry are at risk of exposure to these metals and chemicals. Objective of this study was to conduct quantitative health risk assessment for workers who exposed to metals from an aluminium production industry. The U.S. National Academy of Sciences' four steps of health risk assessment were used to conduct quantitative health risk assessment in this study. This study showed that there were 6 types of metals involved in the aluminium foundry in this study. These metals could cause various health effects but not cancers. Workers were mostly exposed to these metals by inhalation. Calculated reference dose (RfD) for inhalation of aluminium used in this assessment was 0.000015 mg/kg/day. Calculated RID for inhalation of manganese used in this assessment was 0.000002 mg/kg/day. Calculated RfD for inhalation of copper used in this assessment was 0.000028 mg/kg/day. Calculated RID for inhalation of zinc used in this assessment was 0.000083 mg/ kg/day. Calculated RID for inhalation of magnesium used in this assessment was 0.949833 mg/kg/day. Calculated RID for inhalation of iron used in this assessment was 10.6219 mg/kg/day. Maximum daily doses (MDDs) for workers who exposed to metals measured in this foundry were 0, 0, 0.000463, 0.0000927, 0.000162 and 0 mg/kg/day for manganese, zinc, aluminium, iron, magnesium and copper, respectively. Finally, risk characterization for workers exposed to metals in this aluminium foundry showed that workers in this foundry had 31 times higher risk of developing diseases from aluminium than persons who were not exposed to aluminium. These workers had the same risk of developing diseases from other metals and chemicals as persons who were not exposed to those metals and chemicals. Workers who exposed to aluminium in this aluminium production plant had 31 times risk of developing non-carcinogenic effects from aluminium compared with normal

  10. Expression and purification of soluble bio-active rice plant catalase-A from recombinant Escherichia coli.

    PubMed

    Ray, Mamata; Mishra, Panchanand; Das, Priyanka; Sabat, Surendra Chandra

    2012-01-01

    Catalase in plants is a heme-coordinated tetrameric protein that primarily disproportionates hydrogen peroxide into water and oxygen. It plays an important role in maintaining cellular concentration of hydrogen peroxide to a level, necessary for all aspects of normal plant growth and development. Except for its recombinant expression in transgenic plants and insect cell line, the protein is yet to be synthesized in its bio-active form in prokaryotic expression system. Attempts made in past for recombinant expression of plant catalase in Escherichia coli consistently resulted in formation of insoluble and inactive aggregates of inclusion body. Here we have shown the specific requirement of a thioredoxin fusion partner, the involvement of trigger factor protein and the low temperature treatment during induction period for synthesis of completely solubilized rice plant catalase-A in recombinant E. coli. Furthermore, the bacteria required the supplementation of δ-aminolevulinic acid to produce bio-active recombinant rice catalase-A. The molecular and biochemical properties of the purified recombinant protein showed the characteristic features of a typical mono-functional plant catalase. These results attest to the usefulness of the present protocol for production of plant catalase using E. coli as heterologous expression system.

  11. Recent advances in the dissection of drought-stress regulatory networks and strategies for development of drought-tolerant transgenic rice plants

    PubMed Central

    Todaka, Daisuke; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

    2015-01-01

    Advances have been made in the development of drought-tolerant transgenic plants, including cereals. Rice, one of the most important cereals, is considered to be a critical target for improving drought tolerance, as present-day rice cultivation requires large quantities of water and as drought-tolerant rice plants should be able to grow in small amounts of water. Numerous transgenic rice plants showing enhanced drought tolerance have been developed to date. Such genetically engineered plants have generally been developed using genes encoding proteins that control drought regulatory networks. These proteins include transcription factors, protein kinases, receptor-like kinases, enzymes related to osmoprotectant or plant hormone synthesis, and other regulatory or functional proteins. Of the drought-tolerant transgenic rice plants described in this review, approximately one-third show decreased plant height under non-stressed conditions or in response to abscisic acid treatment. In cereal crops, plant height is a very important agronomic trait directly affecting yield, although the improvement of lodging resistance should also be taken into consideration. Understanding the regulatory mechanisms of plant growth reduction under drought stress conditions holds promise for developing transgenic plants that produce high yields under drought stress conditions. Plant growth rates are reduced more rapidly than photosynthetic activity under drought conditions, implying that plants actively reduce growth in response to drought stress. In this review, we summarize studies on molecular regulatory networks involved in response to drought stress. In a separate section, we highlight progress in the development of transgenic drought-tolerant rice plants, with special attention paid to field trial investigations. PMID:25741357

  12. Recent advances in the dissection of drought-stress regulatory networks and strategies for development of drought-tolerant transgenic rice plants.

    PubMed

    Todaka, Daisuke; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

    2015-01-01

    Advances have been made in the development of drought-tolerant transgenic plants, including cereals. Rice, one of the most important cereals, is considered to be a critical target for improving drought tolerance, as present-day rice cultivation requires large quantities of water and as drought-tolerant rice plants should be able to grow in small amounts of water. Numerous transgenic rice plants showing enhanced drought tolerance have been developed to date. Such genetically engineered plants have generally been developed using genes encoding proteins that control drought regulatory networks. These proteins include transcription factors, protein kinases, receptor-like kinases, enzymes related to osmoprotectant or plant hormone synthesis, and other regulatory or functional proteins. Of the drought-tolerant transgenic rice plants described in this review, approximately one-third show decreased plant height under non-stressed conditions or in response to abscisic acid treatment. In cereal crops, plant height is a very important agronomic trait directly affecting yield, although the improvement of lodging resistance should also be taken into consideration. Understanding the regulatory mechanisms of plant growth reduction under drought stress conditions holds promise for developing transgenic plants that produce high yields under drought stress conditions. Plant growth rates are reduced more rapidly than photosynthetic activity under drought conditions, implying that plants actively reduce growth in response to drought stress. In this review, we summarize studies on molecular regulatory networks involved in response to drought stress. In a separate section, we highlight progress in the development of transgenic drought-tolerant rice plants, with special attention paid to field trial investigations.

  13. Ectopic expression of a novel OsExtensin-like gene consistently enhances plant lodging resistance by regulating cell elongation and cell wall thickening in rice.

    PubMed

    Fan, Chunfen; Li, Ying; Hu, Zhen; Hu, Huizhen; Wang, Guangya; Li, Ao; Wang, Youmei; Tu, Yuanyuan; Xia, Tao; Peng, Liangcai; Feng, Shengqiu

    2017-06-02

    Plant lodging resistance is an important integrative agronomic trait of grain yield and quality in crops. Although extensin proteins are tightly associated with plant cell growth and cell wall construction, little has yet been reported about their impacts on plant lodging resistance. In this study, we isolated a novel extensin-like (OsEXTL) gene in rice, and selected transgenic rice plants that expressed OsEXTL under driven with two distinct promoters. Despite different OsEXTL expression levels, two-promoter-driven OsEXTL-transgenic plants, compared to a rice cultivar and an empty vector, exhibited significantly reduced cell elongation in stem internodes, leading to relatively shorter plant heights by 7%-10%. Meanwhile, the OsEXTL-transgenic plants showed remarkably thickened secondary cell walls with higher cellulose levels in the mature plants, resulting in significantly increased detectable mechanical strength (extension and pushing forces) in the mature transgenic plants. Due to reduced plant height and increased plant mechanical strength, the OsEXTL-transgenic plants were detected with largely enhanced lodging resistances in 3 years field experiments, compared to those of the rice cultivar ZH11. In addition, despite relatively short plant heights, the OsEXTL-transgenic plants maintain normal grain yields and biomass production, owing to their increased cellulose levels and thickened cell walls. Hence, this study demonstrates a largely improved lodging resistance in the OsEXTL-transgenic rice plants, and provides insights into novel extensin functions in plant cell growth and development, cell wall network construction and wall structural remodelling. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  14. Cooked rice texture and rice flour pasting properties; impacted by rice temperature during milling.

    PubMed

    Saleh, Mohammed; Meullenet, Jean-Francois

    2015-03-01

    Rice milling plays a key factor in determining rice quality and value. Therefore accurate quality assessments are critical to the rice industry. This study was undertaken to assess the effect of exposing rice to elevated temperatures during milling, on cooked rice texture and rice flour pasting properties. Two long (Cybonnett and Francis) and one medium (Jupiter) rice (oryzae sativa L.) cultivars were milled using McGill laboratory mill for 30 and 40 s after warmed up the mill before milling. Four different milling temperatures per milling duration were achieved. Cooked rice texture properties were assessed using a uniaxial compression test and rice flour pasting properties measured using a TA-2000 rheometer. Results of this study showed that exposure of rice to high temperatures during milling significantly decreased cooked rice firmness. An increase in milled rice temperature after milling from 10.0 to 13.3 °C resulted in a 5.4 and 8.1 N decrease in cooked rice firmness. Although not always significant, the increase in milled rice temperature during milling resulted in an increase in cooked rice stickiness. The increase in milling temperature also showed significant increase in rice flour pasting properties. Changes in rice functional characteristics were attributed to the changes occurring to rice chemical constituents due to temperature exposure as indicated by the increase in rice protein hydrophobicity. Proteins are known to affect rice starch water holding capacity and other starch gelatinization properties.

  15. Pulmonary fibrosis in cable plant workers exposed to mist and vapor of petroleum distillates.

    PubMed

    Skyberg, K; Rønneberg, A; Kamøy, J I; Dale, K; Borgersen, A

    1986-08-01

    Twenty-five cable plant workers exposed to mists and vapors of mineral oils and kerosene for 5-35 years have been investigated in a cross-sectional, matched pairs study. The exposed cohort and the referents were examined by radiology, pulmonary function measurements, and a questionnaire for symptoms of respiratory disease. Lung tissue from a deceased worker with 35 years of exposure was investigated by histopathologic methods and by scanning electron microscopy. Exposure measurements were performed by personal sampling. Previous employment and smoking habits were recorded for all subjects. An increased prevalence of slight basal lung fibrosis was found in chest films of the exposed workers. Pulmonary fibrosis was confirmed histopathologically. A moderately decreased vital capacity (VC) and forced expiratory volume (FEV1) was found. Oil mist was measured to time-weighted average levels of 0.15-0.30 mg/m3 with short-term vapor exposure of up to 4000 mg/m3. It is concluded that mists and vapors from petroleum distillates are the most probable causes of the findings.

  16. Is sulfur accumulation in sulfur dioxide-exposed plants related to biomass reduction

    SciTech Connect

    Lorenzini, G.; Panicucci, A. )

    1994-06-01

    Sulfur (S) is an abundant element in the Earth's crust. It is a major plant nutrient,necessary in plant metabolism. Normally, S is taken up from soil in the sulphate form and assimilated into various compounds. Sulfur dioxide (SO[sub 2]) absorbed from the air can also supply S for nutrition. Of all plant organs, the leaves have the highest S content. SO[sub 2] is an air contaminant, especially a consequence of burning fossil fuels, as well as having significant natural sources. Plants exposed to excessive SO[sub 2] levels may be associated with visible injury and biomass production perturbation. Two questions may be raised: is S accumulation correlated with other responses, such as resistance or tolerance to SO[sub 2] and can S accumulation be a useful tool for diagnostic purposes when SO[sub 2] is suspected of being responsible for altered plants Unfortunately, these questions are not easily answered. It takes a substantial build-up before any increase is significant. Accumulation may also be influenced by the level of S nutrition. Experiments under controlled conditions are essential. Many experiments performed in the past used rather high SO[sub 2] concentrations and short duration, but the extrapolation to [open quote]natural[close quote] situations is difficult. Results here reported refer to experiments carried out in order to get more information on some aspects of sulphur accumulation in plants under realistic, nonmarking, SO[sub 2] pollution conditions, in connection with biomass production. 18 refs., 1 fig., 3 tabs.

  17. Differential morphological, cytological and biochemical responses of two rice cultivars to coumarin

    USDA-ARS?s Scientific Manuscript database

    Plants are often exposed to allelochemicals in the environment produced by neighboring plants. Coumarin is a common allelochemical produced by many higher plants. Two cultivars (susceptible BS-2000 and less susceptible BR-41) of rice (Oryza sativa L.) were selected to compare their differential root...

  18. Bioaccumulation, oxidative stress and genotoxicity in fish (Channa punctatus) exposed to a thermal power plant effluent.

    PubMed

    Javed, Mehjbeen; Ahmad, Irshad; Usmani, Nazura; Ahmad, Masood

    2016-05-01

    Metal bioaccumulation and induction of biomarkers such as lipid peroxidation (LPO), superoxide dismutase (SOD), catalase (CAT), glutathione S transferase (GST), reduced glutathione (GSH) and DNA damage are potential indicators of stress in Channa punctatus exposed to effluents. In canal water, receiving thermal power plant discharges, Fe and Ni concentrations exceeded the recommended guidelines set by the United Nations Environment Programme Global Environment Monitoring System (UNEPGEMS). Fe was highly bioavailable and accumulated in all organs (liver, kidney, muscle and integument). The highest metal pollution index (MPI) value of 41.2 was observed in kidney and the lowest 13.5 in muscle tissue. LPO, SOD, CAT and GST levels were significantly higher in liver and kidney, whereas GSH levels declined significantly compared to fish from the reference site. Concomitant damage to DNA was observed with significantly higher mean tail length in the exposed fish gill cells (26.5µm) and in liver (20.8µm) compared to reference fish. Therefore, it can be concluded that the thermal power plant effluent had the potential to cause oxidative stress and DNA damage in C. punctatus.

  19. Effects of combined amendments on heavy metal accumulation in rice (Oryza sativa L.) planted on contaminated paddy soil.

    PubMed

    Zhou, Hang; Zhou, Xin; Zeng, Min; Liao, Bo-Han; Liu, Li; Yang, Wen-Tao; Wu, Yan-Ming; Qiu, Qiong-Yao; Wang, Ying-Jie

    2014-03-01

    Stabilization of heavy metals in situ was investigated. Two combined amendments (LS, limestone+sepiolite; HZ, hydroxyhistidine+zeolite) were applied at ratios of 0.2%, 0.4%, and 0.8% (w/w) to paddy soil with multi-metal (Pb, Cd, Cu, and Zn) contamination. The effects of these two combined amendments on heavy metal bioavailability in soil, and on uptake and accumulation of heavy metals in rice plants were investigated. Application of LS and HZ significantly increased soil pH values and cation exchange capacity contents, and resulted in a reduction in exchangeable fraction of metals and in extract metal concentrations of amended soils through toxicity characteristic leaching procedure (TCLP). LS and HZ obviously inhibited uptake and accumulation of Pb, Cd, Cu, and Zn in rice plants. Compared with the control soil, concentrations of Pb, Cd, Cu, and Zn in brown rice were decreased by 10.6-31.8%, 16.7-25.5%, 11.5-22.1%, and 11.7-16.3%, respectively, as a result of 0.2% to 0.8% addition of LS, and decreased by 5.1-40.8%, 16.7-20.0%, 8.1-16.2%, and 13.3-21.7%, respectively, as a result of 0.2-0.8% addition of HZ. Significant positive linear correlations were found between heavy metal concentrations in TCLP extracts and those in rice tissues except for Pb. Extracting heavy metals with TCLP was a more suitable method for estimating heavy metal bioavailability concentrations of amended soil than exchangeable fraction of heavy metals, because the latter underestimated heavy metal bioavailability. These results demonstrate that LS and HZ could be effective in reducing heavy metal bioavailability and accumulation in rice grown on multi-metal-contaminated soils. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. [Effects of increased planting density with reduced nitrogen fertilizer application on rice yield, N use efficiency and greenhouse gas emission in Northeast China].

    PubMed

    Zhu, Xiang-cheng; Zhang, Zhen-ping; Zhang, Jun; Deng, Ai-xing; Zhang, Wei-jian

    2016-02-01

    The traditional rice growing practice has to change to save resource and protect environment, and it' s necessary to develop new technology in rice cultivation. Therefore, a two-year field experiment of Japonica rice (Liaoxing 1) was conducted in Northeast China in 2012 and 2013 to investigate the integrated effects of dense planting with less basal nitrogen (N) and unchanged top-dressing N (IR) on rice yield, N use efficiency (NUE) and greenhouse gas emissions. Compared with traditional practice (CK), we increased the rice seedling density by 33.3% and reduced the basal N rate by 20%. The results showed that the average N agronomy efficiency and partial factor productivity were improved by 49.6% (P<0.05) and 20.4% (P<0.05), respectively, while the area and yield-scaled greenhouse gas emissions were reduced by 9.9% and 12.7% (P<0.05), respectively. Although IR cropping mode decreased panicle number and biomass production, it significantly enhanced rice seed setting rate and harvest index, resulting in an unchanged or even highei yield. NH4+-N and NO3(-)-N concentrations in rice rhizosphere soil were reduced, resulting in an increment of N recovery efficiency. Generally, proper dense planting with less basal N applicatior could be a good approach for the trade-off between rice yield, NUE and greenhouse gas emission.

  1. Identification and analysis of brown planthopper-responsive microRNAs in resistant and susceptible rice plants.

    PubMed

    Wu, Yan; Lv, Wentang; Hu, Liang; Rao, Weiwei; Zeng, Ya; Zhu, Lili; He, Yuqing; He, Guangcun

    2017-08-18

    The brown planthopper (BPH) is the most devastating insect pest of rice. The rice gene BPH15 confers resistance to BPH. MicroRNAs (miRNAs) regulate a spectrum of development and defense response processes in plants. In this study, we analyzed six miRNA profiles of a BPH15 introgression line (P15) and a susceptible recipient line (PC) at three time points (0 h, 6 h and 48 h) after BPH attack, and identified 464 known miRNAs and 183 potential novel miRNAs. Before the BPH feeding, we identified 23 miRNAs differentially expressed in P15 and PC. We speculated that the resistant plant is in a priming state by the regulation of miRNAs. After the BPH feeding, 104 miRNAs were found to be expressed differentially in P15 (68 in P15-6/P15-0, 36 in P15-48/P15-0), and 80 miRNAs were found expressed differentially in PC (32 in PC-6/PC-0, 48 in PC-48/PC-0), which illustrated that miRNA expression is activated upon attack. These miRNAs regulate different pathways that contribute to the basal defense and specific resistance of rice to the BPH. Our study provides additional data for scientists to further explore the mechanism of plant defense against insect attack and to find a way for efficient insect control.

  2. 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.

  3. 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.

  4. 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.

  5. Field response of aboveground non-target arthropod community to transgenic Bt-Cry1Ab rice plant residues in postharvest seasons.

    PubMed

    Bai, Yao-Yu; Yan, Rui-Hong; Ye, Gong-Yin; Huang, Fangneng; Wangila, David S; Wang, Jin-Jun; Cheng, Jia-An

    2012-10-01

    Risk assessments of ecological effects of transgenic rice expressing lepidoptera-Cry proteins from Bacillus thuringiensis (Bt) on non-target arthropods have primarily focused on rice plants during cropping season, whereas few studies have investigated the effects in postharvest periods. Harvested rice fallow fields provide a critical over-wintering habitat for arthropods in the Chinese rice ecosystems, particularly in the southern region of the country. During 2006-08, two independent field trials were conducted in Chongqing, China to investigate the effects of transgenic Cry1Ab rice residues on non-target arthropod communities. In each trial, pitfall traps were used to sample arthropods in field plots planted with one non-Bt variety and two Bt rice lines expressing the Cry1Ab protein. Aboveground arthropods in the trial plots during the postharvest season were abundant, while community densities varied significantly between the two trials. A total of 52,386 individual insects and spiders, representing 93 families, was captured in the two trials. Predominant arthropods sampled were detritivores, which accounted for 91.9% of the total captures. Other arthropods sampled included predators (4.2%), herbivores (3.2%), and parasitoids (0.7%). In general, there were no significant differences among non-Bt and Bt rice plots in all arthropod community-specific parameters for both trials, suggesting no adverse impact of the Bt rice plant residues on the aboveground non-target arthropod communities during the postharvest season. The results of this study provide additional evidence that Bt rice is safe to non-target arthropod communities in the Chinese rice ecosystems.

  6. Mapping paddy rice planting area in cold temperate climate region through analysis of time series Landsat 8 (OLI), Landsat 7 (ETM+) and MODIS imagery

    PubMed Central

    Qin, Yuanwei; Xiao, Xiangming; Dong, Jinwei; Zhou, Yuting; Zhu, Zhe; Zhang, Geli; Du, Guoming; Jin, Cui; Kou, Weili; Wang, Jie; Li, Xiangping

    2016-01-01

    Accurate and timely rice paddy field maps with a fine spatial resolution would greatly improve our understanding of the effects of paddy rice agriculture on greenhouse gases emissions, food and water security, and human health. Rice paddy field maps were developed using optical images with high temporal resolution and coarse spatial resolution (e.g., Moderate Resolution Imaging Spectroradiometer (MODIS)) or low temporal resolution and high spatial resolution (e.g., Landsat TM/ETM+). In the past, the accuracy and efficiency for rice paddy field mapping at fine spatial resolutions were limited by the poor data availability and image-based algorithms. In this paper, time series MODIS and Landsat ETM+/OLI images, and the pixel- and phenology-based algorithm are used to map paddy rice planting area. The unique physical features of rice paddy fields during the flooding/open-canopy period are captured with the dynamics of vegetation indices, which are then used to identify rice paddy fields. The algorithm is tested in the Sanjiang Plain (path/row 114/27) in China in 2013. The overall accuracy of the resulted map of paddy rice planting area generated by both Landsat ETM+ and OLI is 97.3%, when evaluated with areas of interest (AOIs) derived from geo-referenced field photos. The paddy rice planting area map also agrees reasonably well with the official statistics at the level of state farms (R2 = 0.94). These results demonstrate that the combination of fine spatial resolution images and the phenology-based algorithm can provide a simple, robust, and automated approach to map the distribution of paddy rice agriculture in a year. PMID:27695195

  7. Mapping paddy rice planting area in cold temperate climate region through analysis of time series Landsat 8 (OLI), Landsat 7 (ETM+) and MODIS imagery.

    PubMed

    Qin, Yuanwei; Xiao, Xiangming; Dong, Jinwei; Zhou, Yuting; Zhu, Zhe; Zhang, Geli; Du, Guoming; Jin, Cui; Kou, Weili; Wang, Jie; Li, Xiangping

    2015-07-01

    Accurate and timely rice paddy field maps with a fine spatial resolution would greatly improve our understanding of the effects of paddy rice agriculture on greenhouse gases emissions, food and water security, and human health. Rice paddy field maps were developed using optical images with high temporal resolution and coarse spatial resolution (e.g., Moderate Resolution Imaging Spectroradiometer (MODIS)) or low temporal resolution and high spatial resolution (e.g., Landsat TM/ETM+). In the past, the accuracy and efficiency for rice paddy field mapping at fine spatial resolutions were limited by the poor data availability and image-based algorithms. In this paper, time series MODIS and Landsat ETM+/OLI images, and the pixel- and phenology-based algorithm are used to map paddy rice planting area. The unique physical features of rice paddy fields during the flooding/open-canopy period are captured with the dynamics of vegetation indices, which are then used to identify rice paddy fields. The algorithm is tested in the Sanjiang Plain (path/row 114/27) in China in 2013. The overall accuracy of the resulted map of paddy rice planting area generated by both Landsat ETM+ and OLI is 97.3%, when evaluated with areas of interest (AOIs) derived from geo-referenced field photos. The paddy rice planting area map also agrees reasonably well with the official statistics at the level of state farms (R(2) = 0.94). These results demonstrate that the combination of fine spatial resolution images and the phenology-based algorithm can provide a simple, robust, and automated approach to map the distribution of paddy rice agriculture in a year.

  8. Mapping paddy rice planting area in cold temperate climate region through analysis of time series Landsat 8 (OLI), Landsat 7 (ETM+) and MODIS imagery

    NASA Astrophysics Data System (ADS)

    Qin, Yuanwei; Xiao, Xiangming; Dong, Jinwei; Zhou, Yuting; Zhu, Zhe; Zhang, Geli; Du, Guoming; Jin, Cui; Kou, Weili; Wang, Jie; Li, Xiangping

    2015-07-01

    Accurate and timely rice paddy field maps with a fine spatial resolution would greatly improve our understanding of the effects of paddy rice agriculture on greenhouse gases emissions, food and water security, and human health. Rice paddy field maps were developed using optical images with high temporal resolution and coarse spatial resolution (e.g., Moderate Resolution Imaging Spectroradiometer (MODIS)) or low temporal resolution and high spatial resolution (e.g., Landsat TM/ETM+). In the past, the accuracy and efficiency for rice paddy field mapping at fine spatial resolutions were limited by the poor data availability and image-based algorithms. In this paper, time series MODIS and Landsat ETM+/OLI images, and the pixel- and phenology-based algorithm are used to map paddy rice planting area. The unique physical features of rice paddy fields during the flooding/open-canopy period are captured with the dynamics of vegetation indices, which are then used to identify rice paddy fields. The algorithm is tested in the Sanjiang Plain (path/row 114/27) in China in 2013. The overall accuracy of the resulted map of paddy rice planting area generated by both Landsat ETM+ and OLI is 97.3%, when evaluated with areas of interest (AOIs) derived from geo-referenced field photos. The paddy rice planting area map also agrees reasonably well with the official statistics at the level of state farms (R2 = 0.94). These results demonstrate that the combination of fine spatial resolution images and the phenology-based algorithm can provide a simple, robust, and automated approach to map the distribution of paddy rice agriculture in a year.

  9. Molecular dissection of developmental behavior of tiller number and plant height and their relationship in rice (Oryza sativa L.).

    PubMed

    Yang, Guohua; Xing, Yongzhong; Li, Shaoqing; Ding, Jingzhen; Yue, Bing; Deng, Kai; Li, Yangsheng; Zhu, Yingguo

    2006-12-01

    Plant height and tiller number are two important characters related to yield in rice (Oriza sativa L.). Zhenshan97 x Minghui63 recombinant inbred lines were employed to dissect the genetic basis of development of plant height and tiller number using conditional and unconditional composite interval mapping approaches. The traits were normally distributed with transgressive segregation in both directions. Increasingly negative correlations were observed between tiller number and plant height at five consecutive growth stages. A total of 23 and 24 QTL were identified for tiller number and plant height, respectively. More QTL were detected by conditional mapping than by conventional mapping. Different QTL/genes apparently controlled the traits at different developmental stages. Three genomic regions were identified as putative co-located QTL, which showed opposite additive effects on tiller number and plant height. Furthermore, in the period reaching maximum tiller number, the expression of QTL for tiller number was active, whereas that of QTL for plant height was inactive. These facts provided a possible genetic explanation for the negative correlations between the traits. The research demonstrates conditional mapping to be superior to conventional mapping for this type of research. Implications of the results for hybrid rice improvement are discussed.

  10. Biomonitoring of a worker population exposed to platinum dust in a catalyst production plant

    PubMed Central

    Petrucci, F; Violante, N; Senofonte, O; Cristaudo, A; Di, G; Forte, G; Alimonti, A

    2005-01-01

    Aims: To evaluate the occupational exposure to platinum in an industrial plant engaged in the production, recovery, and recycling of catalytic converters for the automotive traction and chemical industries. Methods: Pt was determined in airborne particulate matter, and blood, urine, and hair of 106 exposed workers, 21 controls from the plant's administrative offices, and 25 unexposed subjects. Results: The highest air Pt level was found in the department of the plant in which supports are coated with acid metal solutions, where values of 2.39 and 4.83 µg/m3 respectively were found in environmental airborne particulate matter and in air collected using personal sampler devices. The percentage of soluble Pt was also highest in this area, varying from 24% to 44% of the total. The biological data confirmed this trend, with mean concentrations in this site being higher than in other working areas: 1.86 µg/l (urine), 0.38 µg/l (blood), and 2.26 µg/kg (hair). The workers employed in the administrative sector, who were not directly exposed to Pt, had levels of contaminant lower than those of other workers, albeit 2–20 times higher than those of external controls. High correlations were obtained between Pt levels detected in airborne samples using personal devices and those found in urine and hair, but not in blood. Conclusions: The background level of Pt in all areas of the factory implies widespread exposure for the workers. The most reliable biomarker was urine. Hair cannot be considered a good index of time related exposure, at least until more reliable methods of washing can be found that are able to remove exogenous Pt completely. PMID:15613605

  11. Regulatory interplay of the Sub1A and CIPK15 pathways in the regulation of α-amylase production in flooded rice plants.

    PubMed

    Kudahettige, N P; Pucciariello, C; Parlanti, S; Alpi, A; Perata, P

    2011-07-01

    Rice (Oryza sativa L.) can successfully germinate and grow even when flooded. Rice varieties possessing the submergence 1A (Sub1A) gene display a distinct flooding-tolerant phenotype, associated with lower carbohydrate consumption and restriction of the fast-elongation phenotype typical of flooding-intolerant rice varieties. Calcineurin B-like interacting protein kinase 15 (CIPK15) was recently indicated as a key regulator of α-amylases under oxygen deprivation, linked to both rice germination and flooding tolerance in adult plants. It is still unknown whether the Sub1A- and CIPK15-mediated pathways act as complementary processes for rice survival under O(2) deprivation. In adult plants Sub1A and CIPK15 may perhaps play an antagonistic role in terms of carbohydrate consumption, with Sub1A acting as a starch degradation repressor and CIPK15 as an activator. In this study, we analysed sugar metabolism in the stem of rice plants under water submergence by selecting cultivars with different traits associated with flooding survival. The relation between the Sub1A and the CIPK15 pathways was investigated. The results show that under O(2) deprivation, the CIPK15 pathway is repressed in the tolerant, Sub1A-containing, FR13A variety. CIPK15 is likely to play a role in the up-regulation of Ramy3D in flooding-intolerant rice varieties that display fast elongation under flooding and that do not possess Sub1A.

  12. Alternate crop and weed host plant oviposition preferences by the Mexican rice borer (Lepidoptera: Crambidae)

    USDA-ARS?s Scientific Manuscript database

    The Mexican rice borer, Eoreuma loftini (Dyar), is the key pest of sugarcane, Saccharum hybrids, in south Texas, having largely displaced the sugarcane borer, Diatraea saccharalis (F.), and it is moving into rice- and sugarcane-growing areas of east Texas and Louisiana. While a number of alternativ...

  13. 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.

  14. Gibberellin homeostasis and plant height control by EUI and a role for gibberellin in root gravity responses in rice.

    PubMed

    Zhang, Yingying; Zhu, Yongyou; Peng, Yu; Yan, Dawei; Li, Qun; Wang, Jianjun; Wang, Linyou; He, Zuhua

    2008-03-01

    The rice Eui (ELONGATED UPPERMOST INTERNODE) gene encodes a cytochrome P450 monooxygenase that deactivates bioactive gibberellins (GAs). In this study, we investigated controlled expression of the Eui gene and its role in plant development. We found that Eui was differentially induced by exogenous GAs and that the Eui promoter had the highest activity in the vascular bundles. The eui mutant was defective in starch granule development in root caps and Eui overexpression enhanced starch granule generation and gravity responses, revealing a role for GA in root starch granule development and gravity responses. Experiments using embryoless half-seeds revealed that RAmy1A and GAmyb were highly upregulated in eui aleurone cells in the absence of exogenous GA. In addition, the GA biosynthesis genes GA3ox1 and GA20ox2 were downregulated and GA2ox1 was upregulated in eui seedlings. These results indicate that EUI is involved in GA homeostasis, not only in the internodes at the heading stage, but also in the seedling stage, roots and seeds. Disturbing GA homeostasis affected the expression of the GA signaling genes GID1 (GIBBERELLIN INSENSITIVE DWARF 1), GID2 and SLR1. Transgenic RNA interference of the Eui gene effectively increased plant height and improved heading performance. By contrast, the ectopic expression of Eui under the promoters of the rice GA biosynthesis genes GA3ox2 and GA20ox2 significantly reduced plant height. These results demonstrate that a slight increase in Eui expression could dramatically change rice morphology, indicating the practical application of the Eui gene in rice molecular breeding for a high yield potential.

  15. Performance evaluation of various classifiers for color prediction of rice paddy plant leaf

    NASA Astrophysics Data System (ADS)

    Singh, Amandeep; Singh, Maninder Lal

    2016-11-01

    The food industry is one of the industries that uses machine vision for a nondestructive quality evaluation of the produce. These quality measuring systems and softwares are precalculated on the basis of various image-processing algorithms which generally use a particular type of classifier. These classifiers play a vital role in making the algorithms so intelligent that it can contribute its best while performing the said quality evaluations by translating the human perception into machine vision and hence machine learning. The crop of interest is rice, and the color of this crop indicates the health status of the plant. An enormous number of classifiers are available to solve the purpose of color prediction, but choosing the best among them is the focus of this paper. Performance of a total of 60 classifiers has been analyzed from the application point of view, and the results have been discussed. The motivation comes from the idea of providing a set of classifiers with excellent performance and implementing them on a single algorithm for the improvement of machine vision learning and, hence, associated applications.

  16. Plant growth-promoting traits of biocontrol potential bacteria isolated from rice rhizosphere.

    PubMed

    Gopalakrishnan, Subramaniam; Upadhyaya, Hd; Vadlamudi, Srinivas; Humayun, Pagidi; Vidya, Meesala Sree; Alekhya, Gottumukkala; Singh, Amit; Vijayabharathi, Rajendran; Bhimineni, Ratna Kumari; Seema, Murali; Rathore, Abhishek; Rupela, Om

    2012-12-01

    Seven isolates of bacteria (SRI-156, SRI-158, SRI-178, SRI-211, SRI-229, SRI-305 and SRI-360) were earlier reported by us as having potential for biocontrol of charcoal rot of sorghum and plant growth promotion (PGP) of the plant. In the present study, the seven isolates were characterized for their physiological traits (tolerance to salinity, pH, temperature and resistance to antibiotics and fungicides) and further evaluated in the field for their PGP of rice. All the seven isolates were able to grow at pH values between 5 and 13, in NaCl concentrations of up to 8% (except SRI-156 and SRI-360), temperatures between 20 and 40°C and were resistant to ampicillin (>100 ppm; except SRI-158 and SRI-178) but sensitive (<10 ppm) to chloramphenicol, kanamycin, nalidixic acid, streptomycin (except SRI-156 and SRI-211) and tetracycline. They were tolerant to fungicides benlate and captan, except SRI-158 and SRI-178, bavistin and sensitive to thiram (except SRI-156 and SRI-211) at field application level. In the field, four of the seven isolates (SRI-158, SRI-211, SRI-229 and SRI-360) significantly enhanced the tiller numbers, stover and grain yields, total dry matter, root length, volume and dry weight over the un-inoculated control. In the rhizosphere soil at harvest, all the isolates significantly enhanced microbial biomass carbon (except SRI-156), microbial biomass nitrogen and dehydrogenase activity (up to 33%, 36% and 39%, respectively) and total N, available P and% organic carbon (up to 10%, 38% and 10%, respectively) compared to the control. This investigation further confirms that the SRI isolates have PGP properties.

  17. Microarray analysis of tomato plants exposed to the nonviruliferous or viruliferous whitefly vector harboring Pepper golden mosaic virus.

    PubMed

    Musser, Richard O; Hum-Musser, Sue M; Gallucci, Matthew; DesRochers, Brittany; Brown, Judith K

    2014-01-01

    Plants are routinely exposed to biotic and abiotic stresses to which they have evolved by synthesizing constitutive and induced defense compounds. Induced defense compounds are usually made, initially, at low levels; however, following further stimulation by specific kinds of biotic and abiotic stresses, they can be synthesized in relatively large amounts to abate the particular stress. cDNA microarray hybridization was used to identify an array of genes that were differentially expressed in tomato plants 15 d after they were exposed to feeding by nonviruliferous whiteflies or by viruliferous whiteflies carrying Pepper golden mosaic virus (PepGMV) (Begomovirus, Geminiviridae). Tomato plants inoculated by viruliferous whiteflies developed symptoms characteristic of PepGMV, whereas plants exposed to nonviruliferous whitefly feeding or nonwounded (negative) control plants exhibited no disease symptoms. The microarray analysis yielded over 290 spotted probes, with significantly altered expression of 161 putative annotated gene targets, and 129 spotted probes of unknown identities. The majority of the differentially regulated "known" genes were associated with the plants exposed to viruliferous compared with nonviruliferous whitefly feeding. Overall, significant differences in gene expression were represented by major physiological functions including defense-, pathogen-, photosynthesis-, and signaling-related responses and were similar to genes identified for other insect-plant systems. Viruliferous whitefly-stimulated gene expression was validated by real-time quantitative polymerase chain reaction of selected, representative candidate genes (messenger RNA): arginase, dehydrin, pathogenesis-related proteins 1 and -4, polyphenol oxidase, and several protease inhibitors. This is the first comparative profiling of the expression of tomato plants portraying different responses to biotic stress induced by viruliferous whitefly feeding (with resultant virus infection

  18. Genome-Wide Association Study for Plant Height and Grain Yield in Rice under Contrasting Moisture Regimes

    PubMed Central

    Ma, Xiaosong; Feng, Fangjun; Wei, Haibin; Mei, Hanwei; Xu, Kai; Chen, Shoujun; Li, Tianfei; Liang, Xiaohua; Liu, Hongyan; Luo, Lijun

    2016-01-01

    Drought is one of the vitally critical environmental stresses affecting both growth and yield potential in rice. Drought resistance is a complicated quantitative trait that is regulated by numerous small effect loci and hundreds of genes controlling various morphological and physiological responses to drought. For this study, 270 rice landraces and cultivars were analyzed for their drought resistance. This was done via determination of changes in plant height and grain yield under contrasting water regimes, followed by detailed identification of the underlying genetic architecture via genome-wide association study (GWAS). We controlled population structure by setting top two eigenvectors and combining kinship matri