RNA-Seq reveals virus–virus and virus–plant interactions in nature

PubMed Central

Kamitani, Mari; Nagano, Atsushi J.; Honjo, Mie N.; Kudoh, Hiroshi

2016-01-01

Abstract As research on plant viruses has focused mainly on crop diseases, little is known about these viruses in natural environments. To understand the ecology of viruses in natural systems, comprehensive information on virus–virus and virus–host interactions is required. We applied RNA-Seq to plants from a natural population of Arabidopsis halleri subsp. gemmifera to simultaneously determine the presence/absence of all sequence-reported viruses, identify novel viruses and quantify the host transcriptome. By introducing the criteria of read number and genome coverage, we detected infections by Turnip mosaic virus (TuMV), Cucumber mosaic virus and Brassica yellows virus. Active TuMV replication was observed by ultramicroscopy. De novo assembly further identified a novel partitivirus, Arabidopsis halleri partitivirus 1. Interestingly, virus reads reached a maximum level that was equivalent to that of the host's total mRNA, although asymptomatic infection was common. AhgAGO2, a key gene in host defence systems, was upregulated in TuMV-infected plants. Multiple infection was frequent in TuMV-infected leaves, suggesting that TuMV facilitates multiple infection, probably by suppressing host RNA silencing. Revealing hidden plant–virus interactions in nature can enhance our understanding of biological interactions and may have agricultural applications. PMID:27549115

Suppressive effects of 3-methylcholanthrene on the in vitro antitumor activity of naturally cytotoxic cells

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

Lill, P.H.; Gangemi, D.

1986-01-01

Transient suppression of splenic natural killer (NK), natural cytotoxic (NC) and peritoneal macrophage cytotoxicity was observed following a single injection of 3-methylcholanthrene (3-MC) into C3H/HeN mice. Natural killer cell activity was depressed by 30-60% 4-6 d after injection of 1.0 mg 3-MC. Levels of NK reactivity returned to normal 8 d post 3-MC injection, and no suppression of natural killing was seen when tested 6 wk after 3-MC treatment. 3-MC did not affect propionibacterium acnes augmentation of NK cell activity when tested both 6 d and 6 wk after carcinogen injection. The results indicate that the observed suppression of naturallymore » cytotoxic cells may not be important in allowing 3-MC-induced tumors to grow, since suppression is not long-lasting. Therefore, any effect on tumor growth mediated by a suppression of naturally cytotoxic cells would have to be exerted at the earliest stages of tumor development.« less

Mimicry technology: suppressing small RNA activity in plants.

PubMed

Rubio-Somoza, Ignacio; Manavella, Pablo Andrés

2011-01-01

Small RNA suppression constitutes one of the major difficulties for a full molecular characterization of their specific roles in plants. Taking advantage of the latest insights into the new post-biogenesis layer of regulation in microRNA (miRNA) activity, it is possible to overcome the above-mentioned limitation (Nat Genet 39:1033-1037, 2007). We engineered the IPS1 non-coding RNA to bear a complementary sequence to a given miRNA family, resulting in specific sequestration of RISC complexes. MIMIC technology allows for the constitutive release of all of the potential targets of a miRNA family as well as tissue-specific and inducible suppression of its activity.

Plum pox virus capsid protein suppresses plant pathogen-associated molecular pattern (PAMP)-triggered immunity.

PubMed

Nicaise, Valerie; Candresse, Thierry

2017-08-01

The perception of pathogen-associated molecular patterns (PAMPs) by immune receptors launches defence mechanisms referred to as PAMP-triggered immunity (PTI). Successful pathogens must suppress PTI pathways via the action of effectors to efficiently colonize their hosts. So far, plant PTI has been reported to be active against most classes of pathogens, except viruses, although this defence layer has been hypothesized recently as an active part of antiviral immunity which needs to be suppressed by viruses for infection success. Here, we report that Arabidopsis PTI genes are regulated upon infection by viruses and contribute to plant resistance to Plum pox virus (PPV). Our experiments further show that PPV suppresses two early PTI responses, the oxidative burst and marker gene expression, during Arabidopsis infection. In planta expression of PPV capsid protein (CP) was found to strongly impair these responses in Nicotiana benthamiana and Arabidopsis, revealing its PTI suppressor activity. In summary, we provide the first clear evidence that plant viruses acquired the ability to suppress PTI mechanisms via the action of effectors, highlighting a novel strategy employed by viruses to escape plant defences. © 2016 BSPP AND JOHN WILEY & SONS LTD.

Quantifying the effect of crop spatial arrangement on weed suppression using functional-structural plant modelling.

PubMed

Evers, Jochem B; Bastiaans, Lammert

2016-05-01

Suppression of weed growth in a crop canopy can be enhanced by improving crop competitiveness. One way to achieve this is by modifying the crop planting pattern. In this study, we addressed the question to what extent a uniform planting pattern increases the ability of a crop to compete with weed plants for light compared to a random and a row planting pattern, and how this ability relates to crop and weed plant density as well as the relative time of emergence of the weed. To this end, we adopted the functional-structural plant modelling approach which allowed us to explicitly include the 3D spatial configuration of the crop-weed canopy and to simulate intra- and interspecific competition between individual plants for light. Based on results of simulated leaf area development, canopy photosynthesis and biomass growth of the crop, we conclude that differences between planting pattern were small, particularly if compared to the effects of relative time of emergence of the weed, weed density and crop density. Nevertheless, analysis of simulated weed biomass demonstrated that a uniform planting of the crop improved the weed-suppression ability of the crop canopy. Differences in weed suppressiveness between planting patterns were largest with weed emergence before crop emergence, when the suppressive effect of the crop was only marginal. With simultaneous emergence a uniform planting pattern was 8 and 15 % more competitive than a row and a random planting pattern, respectively. When weed emergence occurred after crop emergence, differences between crop planting patterns further decreased as crop canopy closure was reached early on regardless of planting pattern. We furthermore conclude that our modelling approach provides promising avenues to further explore crop-weed interactions and aid in the design of crop management strategies that aim at improving crop competitiveness with weeds.

Limiting similarity and Darwin's naturalization hypothesis: understanding the drivers of biotic resistance against invasive plant species.

PubMed

Yannelli, F A; Koch, C; Jeschke, J M; Kollmann, J

2017-03-01

Several hypotheses have been proposed to explain biotic resistance of a recipient plant community based on reduced niche opportunities for invasive alien plant species. The limiting similarity hypothesis predicts that invasive species are less likely to establish in communities of species holding similar functional traits. Likewise, Darwin's naturalization hypothesis states that invasive species closely related to the native community would be less successful. We tested both using the invasive alien Ambrosia artemisiifolia L. and Solidago gigantea Aiton, and grassland species used for ecological restoration in central Europe. We classified all plant species into groups based on functional traits obtained from trait databases and calculated the phylogenetic distance among them. In a greenhouse experiment, we submitted the two invasive species at two propagule pressures to competition with communities of ten native species from the same functional group. In another experiment, they were submitted to pairwise competition with native species selected from each functional group. At the community level, highest suppression for both invasive species was observed at low propagule pressure and not explained by similarity in functional traits. Moreover, suppression decreased asymptotically with increasing phylogenetic distance to species of the native community. When submitted to pairwise competition, suppression for both invasive species was also better explained by phylogenetic distance. Overall, our results support Darwin's naturalization hypothesis but not the limiting similarity hypothesis based on the selected traits. Biotic resistance of native communities against invasive species at an early stage of establishment is enhanced by competitive traits and phylogenetic relatedness.

Host plant species determines symbiotic bacterial community mediating suppression of plant defenses

USDA-ARS?s Scientific Manuscript database

Herbivore associated bacteria are vital mediators of plant and insect interactions. Host plants play an important role in shaping the gut bacterial community of insects. Colorado potato beetles (CPB; Leptinotarsa decemlineata) use several Solanum plants as hosts in their natural environment. We prev...

Effectors from Wheat Rust Fungi Suppress Multiple Plant Defense Responses.

PubMed

Ramachandran, Sowmya R; Yin, Chuntao; Kud, Joanna; Tanaka, Kiwamu; Mahoney, Aaron K; Xiao, Fangming; Hulbert, Scot H

2017-01-01

Fungi that cause cereal rust diseases (genus Puccinia) are important pathogens of wheat globally. Upon infection, the fungus secretes a number of effector proteins. Although a large repository of putative effectors has been predicted using bioinformatic pipelines, the lack of available high-throughput effector screening systems has limited functional studies on these proteins. In this study, we mined the available transcriptomes of Puccinia graminis and P. striiformis to look for potential effectors that suppress host hypersensitive response (HR). Twenty small (<300 amino acids), secreted proteins, with no predicted functions were selected for the HR suppression assay using Nicotiana benthamiana, in which each of the proteins were transiently expressed and evaluated for their ability to suppress HR caused by four cytotoxic effector-R gene combinations (Cp/Rx, ATR13/RPP13, Rpt2/RPS-2, and GPA/RBP-1) and one mutated R gene-Pto(Y207D). Nine out of twenty proteins, designated Shr1 to Shr9 (suppressors of hypersensitive response), were found to suppress HR in N. benthamiana. These effectors varied in the effector-R gene defenses they suppressed, indicating these pathogens can interfere with a variety of host defense pathways. In addition to HR suppression, effector Shr7 also suppressed PAMP-triggered immune response triggered by flg22. Finally, delivery of Shr7 through Pseudomonas fluorescens EtHAn suppressed nonspecific HR induced by Pseudomonas syringae DC3000 in wheat, confirming its activity in a homologous system. Overall, this study provides the first evidence for the presence of effectors in Puccinia species suppressing multiple plant defense responses.

Complementarity among natural enemies enhances pest suppression.

PubMed

Dainese, Matteo; Schneider, Gudrun; Krauss, Jochen; Steffan-Dewenter, Ingolf

2017-08-15

Natural enemies have been shown to be effective agents for controlling insect pests in crops. However, it remains unclear how different natural enemy guilds contribute to the regulation of pests and how this might be modulated by landscape context. In a field exclusion experiment in oilseed rape (OSR), we found that parasitoids and ground-dwelling predators acted in a complementary way to suppress pollen beetles, suggesting that pest control by multiple enemies attacking a pest during different periods of its occurrence in the field improves biological control efficacy. The density of pollen beetle significantly decreased with an increased proportion of non-crop habitats in the landscape. Parasitism had a strong effect on pollen beetle numbers in landscapes with a low or intermediate proportion of non-crop habitats, but not in complex landscapes. Our results underline the importance of different natural enemy guilds to pest regulation in crops, and demonstrate how biological control can be strengthened by complementarity among natural enemies. The optimization of natural pest control by adoption of specific management practices at local and landscape scales, such as establishing non-crop areas, low-impact tillage, and temporal crop rotation, could significantly reduce dependence on pesticides and foster yield stability through ecological intensification in agriculture.

Natural suppression of Meloidogyne incognita by Pasteuria penetrans in cotton

USDA-ARS?s Scientific Manuscript database

The endospore-forming bacterium Pasteuria penetrans is an obligate parasite of root-knot nematodes (Meloidogyne spp.). This bacterium is commonly found in agricultural soils and has been associated with suppression of Meloidogyne spp. In a field site naturally infested with both P. penetrans and M...

Suppression of Host Photosynthesis by the Parasitic Plant Rhinanthus minor

PubMed Central

Cameron, Duncan D.; Geniez, Jean-Michelle; Seel, Wendy E.; Irving, Louis J.

2008-01-01

Background and Aims Parasitism is well understood to have wide-ranging deleterious effects on host performance in species thus far characterized. Photosynthetic performance reductions have been noted in the Striga–Zea mays association; however, no such information exists for facultative hemiparasitic plants and their hosts, nor are the effects of host species understood. Methods Chlorophyll fluorimetry was used to study the effects of parasitism by the hemiparasite Rhinanthus minor on the grass Phleum bertolinii and the forb Plantago lanceolata, and the effects of host species on the photosynthetic apparatus of R. minor. Key Results Parasitism by Rhinanthus led to a significant decrease in the host, and total (host + parasite) biomass in Phleum; however, in Plantago, no significant repression of growth was noted. Maximum quantum yield (Fv/Fm) was reduced in parasitized Plantago, relative to control plants, but not in Phleum. Fv/Fm was significantly lower in R. minor parasitizing Phleum than Plantago, suggesting Phleum to be a superior host to Plantago for R. minor. Steady-state quantum yield (ΦPSII) was significantly depressed in parasitized Phleum, but only at low irradiances in Plantago. ΦPSII was very low for R. minor grown on Plantago, but not Phleum. Conclusions Shown here is the first evidence of the suppression of host photosynthesis by a facultative hemiparasitic plant, which has significant effects on total biomass production. Host identity is a significant factor in parasite success, with the forb Plantago lanceolata exhibiting apparent chemical as well as previously identified physical defences to parasitism. It is proposed that the electron transport rate (as denoted by ΦPSII) represents the limiting factor for biomass accumulation in this system, and that Plantago is able to suppress the growth of Rhinanthus by suppressing the electron transport rate. PMID:18211886

Chapter 14: Effects of fire suppression and postfire management activities on plant invasions

Treesearch

Matthew L. Brooks

2008-01-01

This chapter explains how various fire suppression and postfire management activities can increase or decrease the potential for plant invasions following fire. A conceptual model is used to summarize the basic processes associated with plant invasions and show how specific fire management activities can be designed to minimize the potential for invasion. The...

Assessment and management of soil microbial community structure for disease suppression.

PubMed

Mazzola, Mark

2004-01-01

Identification of the biological properties contributing to the function of suppressive soils is a necessary first step to the management of such systems for use in the control of soilborne diseases. The development and application of molecular methods for the characterization and monitoring of soil microbial properties will enable a more rapid and detailed assessment of the biological nature of soil suppressiveness. Although suppressive soils have provided a wealth of microbial resources that have subsequently been applied for the biological control of soilborne plant pathogens, the full functional capabilities of the phenomena have not been realized in production agricultural ecosystems. Cultural practices, such as the application of soil amendments, have the capacity to enhance disease suppression, though the biological modes of action may vary from that initially resident to the soil. Plants have a distinct impact on characteristics and activity of resident soil microbial communities, and therefore play an important role in determining the development of the disease-suppressive state. Likewise, plant genotype will modulate these same biological communities, and should be considered when developing strategies to exploit the potential of such a natural disease control system. Implementation of consistently effective practices to manage this resource in an economically and environmentally feasible manner will require more detailed investigation of these biologically complex systems and refinement of currently available methodologies.

Isolation and Identification of Plant Growth Promoting Rhizobacteria from Cucumber Rhizosphere and Their Effect on Plant Growth Promotion and Disease Suppression

PubMed Central

Islam, Shaikhul; Akanda, Abdul M.; Prova, Ananya; Islam, Md. T.; Hossain, Md. M.

2016-01-01

Plant growth promoting rhizobacteria (PGPR) are the rhizosphere bacteria that may be utilized to augment plant growth and suppress plant diseases. The objectives of this study were to identify and characterize PGPR indigenous to cucumber rhizosphere in Bangladesh, and to evaluate their ability to suppress Phytophthora crown rot in cucumber. A total of 66 isolates were isolated, out of which 10 (PPB1, PPB2, PPB3, PPB4, PPB5, PPB8, PPB9, PPB10, PPB11, and PPB12) were selected based on their in vitro plant growth promoting attributes and antagonism of phytopathogens. Phylogenetic analysis of 16S rRNA sequences identified these isolates as new strains of Pseudomonas stutzeri, Bacillus subtilis, Stenotrophomonas maltophilia, and Bacillus amyloliquefaciens. The selected isolates produced high levels (26.78–51.28 μg mL-1) of indole-3-acetic acid, while significant acetylene reduction activities (1.79–4.9 μmole C2H4 mg-1 protein h-1) were observed in eight isolates. Cucumber plants grown from seeds that were treated with these PGPR strains displayed significantly higher levels of germination, seedling vigour, growth, and N content in root and shoot tissue compared to non-treated control plants. All selected isolates were able to successfully colonize the cucumber roots. Moreover, treating cucumber seeds with these isolates significantly suppressed Phytophthora crown rot caused by Phytophthora capsici, and characteristic morphological alterations in P. capsici hyphae that grew toward PGPR colonies were observed. Since these PGPR inoculants exhibited multiple traits beneficial to the host plants, they may be applied in the development of new, safe, and effective seed treatments as an alternative to chemical fungicides. PMID:26869996

Turnabout Is Fair Play: Herbivory-Induced Plant Chitinases Excreted in Fall Armyworm Frass Suppress Herbivore Defenses in Maize1[OPEN

PubMed Central

Alves, Patrick C.M.S.; Gaffoor, Iffa; Acevedo, Flor E.; Peiffer, Michelle; Jin, Shan; Han, Yang; Shakeel, Samina; Felton, Gary W.

2016-01-01

The perception of herbivory by plants is known to be triggered by the deposition of insect-derived factors such as saliva and oral secretions, oviposition materials, and even feces. Such insect-derived materials harbor chemical cues that may elicit herbivore and/or pathogen-induced defenses in plants. Several insect-derived molecules that trigger herbivore-induced defenses in plants are known; however, insect-derived molecules suppressing them are largely unknown. In this study, we identified two plant chitinases from fall armyworm (Spodoptera frugiperda) larval frass that suppress herbivore defenses while simultaneously inducing pathogen defenses in maize (Zea mays). Fall armyworm larvae feed in enclosed whorls of maize plants, where frass accumulates over extended periods of time in close proximity to damaged leaf tissue. Our study shows that maize chitinases, Pr4 and Endochitinase A, are induced during herbivory and subsequently deposited on the host with the feces. These plant chitinases mediate the suppression of herbivore-induced defenses, thereby increasing the performance of the insect on the host. Pr4 and Endochitinase A also trigger the antagonistic pathogen defense pathway in maize and suppress fungal pathogen growth on maize leaves. Frass-induced suppression of herbivore defenses by deposition of the plant-derived chitinases Pr4 and Endochitinase A is a unique way an insect can co-opt the plant’s defense proteins for its own benefit. It is also a phenomenon unlike the induction of herbivore defenses by insect oral secretions in most host-herbivore systems. PMID:26979328

Ralstonia solanacearum novel E3 ubiquitin ligase (NEL) effectors RipAW and RipAR suppress pattern-triggered immunity in plants.

PubMed

Nakano, Masahito; Oda, Kenji; Mukaihara, Takafumi

2017-07-01

Ralstonia solanacearum is the causal agent of bacterial wilt in solanaceous crops. This pathogen injects more than 70 effector proteins into host plant cells via the Hrp type III secretion system to cause a successful infection. However, the function of these effectors in plant cells, especially in the suppression of plant immunity, remains largely unknown. In this study, we characterized two Ralstonia solanacearum effectors, RipAW and RipAR, which share homology with the IpaH family of effectors from animal and plant pathogenic bacteria, that have a novel E3 ubiquitin ligase (NEL) domain. Recombinant RipAW and RipAR show E3 ubiquitin ligase activity in vitro. RipAW and RipAR localized to the cytoplasm of plant cells and significantly suppressed pattern-triggered immunity (PTI) responses such as the production of reactive oxygen species and the expression of defence-related genes when expressed in leaves of Nicotiana benthamiana. Mutation in the conserved cysteine residue in the NEL domain of RipAW completely abolished the E3 ubiquitin ligase activity in vitro and the ability to suppress PTI responses in plant leaves. These results indicate that RipAW suppresses plant PTI responses through the E3 ubiquitin ligase activity. Unlike other members of the IpaH family of effectors, RipAW and RipAR had no leucine-rich repeat motifs in their amino acid sequences. A conserved C-terminal region of RipAW is indispensable for PTI suppression. Transgenic Arabidopsis plants expressing RipAW and RipAR showed increased disease susceptibility, suggesting that RipAW and RipAR contribute to bacterial virulence in plants.

Tomato Reproductive Success Is Equally Affected by Herbivores That Induce or That Suppress Defenses.

PubMed

Liu, Jie; Legarrea, Saioa; Kant, Merijn R

2017-01-01

Herbivory induces plant defenses. These responses are often costly, yet enable plants under attack to reach a higher fitness than they would have reached without these defenses. Spider mites ( Tetranychus ssp.) are polyphagous plant-pests. While most strains of the species Tetranychus urticae induce defenses at the expense of their performance, the species Tetranychus evansi suppresses plant defenses and thereby maintains a high performance. Most data indicate that suppression is a mite-adaptive trait. Suppression is characterized by a massive down-regulation of plant gene-expression compared to plants infested with defense-inducing mites as well as compared to control plants, albeit to a lesser extent. Therefore, we hypothesized that suppression may also benefit a plant since the resources saved during down-regulation could be used to increase reproduction. To test this hypothesis, we compared fruit and viable seed production of uninfested tomato plants with that of plants infested with defense-inducing or defense-suppressing mites. Mite-infested plants produced fruits faster than control plants albeit in lower total amounts. The T. evansi -infested plants produced the lowest number of fruits. However, the number of viable seeds was equal across treatments at the end of the experiment. Nonetheless, at this stage control plants were still alive and productive and therefore reach a higher lifetime fitness than mite-infested plants. Our results indicate that plants have plastic control over reproduction and can speed up fruit- and seed production when conditions are unfavorable. Moreover, we showed that although suppressed plants are less productive in terms of fruit production than induced plants, their lifetime fitness was equal under laboratory conditions. However, under natural conditions the fitness of plants such as tomato will also depend on the efficiency of seed dispersal by animals. Hence, we argue that the fitness of induced plants in the field may be

Tomato Reproductive Success Is Equally Affected by Herbivores That Induce or That Suppress Defenses

PubMed Central

Liu, Jie; Legarrea, Saioa; Kant, Merijn R.

2017-01-01

Herbivory induces plant defenses. These responses are often costly, yet enable plants under attack to reach a higher fitness than they would have reached without these defenses. Spider mites (Tetranychus ssp.) are polyphagous plant-pests. While most strains of the species Tetranychus urticae induce defenses at the expense of their performance, the species Tetranychus evansi suppresses plant defenses and thereby maintains a high performance. Most data indicate that suppression is a mite-adaptive trait. Suppression is characterized by a massive down-regulation of plant gene-expression compared to plants infested with defense-inducing mites as well as compared to control plants, albeit to a lesser extent. Therefore, we hypothesized that suppression may also benefit a plant since the resources saved during down-regulation could be used to increase reproduction. To test this hypothesis, we compared fruit and viable seed production of uninfested tomato plants with that of plants infested with defense-inducing or defense-suppressing mites. Mite-infested plants produced fruits faster than control plants albeit in lower total amounts. The T. evansi-infested plants produced the lowest number of fruits. However, the number of viable seeds was equal across treatments at the end of the experiment. Nonetheless, at this stage control plants were still alive and productive and therefore reach a higher lifetime fitness than mite-infested plants. Our results indicate that plants have plastic control over reproduction and can speed up fruit- and seed production when conditions are unfavorable. Moreover, we showed that although suppressed plants are less productive in terms of fruit production than induced plants, their lifetime fitness was equal under laboratory conditions. However, under natural conditions the fitness of plants such as tomato will also depend on the efficiency of seed dispersal by animals. Hence, we argue that the fitness of induced plants in the field may be

The Pseudomonas syringae type III effector HopG1 targets mitochondria, alters plant development, and suppresses plant innate immunity

PubMed Central

Block, Anna; Guo, Ming; Li, Guangyong; Elowsky, Christian; Clemente, Thomas E.; Alfano, James R.

2009-01-01

Summary The bacterial plant pathogen Pseudomonas syringae uses a type III protein secretion system to inject type III effectors into plant cells. Primary targets of these effectors appear to be effector-triggered immunity (ETI) and pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI). The type III effector HopG1 is a suppressor of ETI that is broadly conserved in bacterial plant pathogens. Here we show that HopG1 from P. syringae pv. tomato DC3000 also suppresses PTI. Interestingly, HopG1 localizes to plant mitochondria, suggesting that its suppression of innate immunity may be linked to a perturbation of mitochondrial function. While HopG1 possesses no obvious mitochondrial signal peptide, its N-terminal two-thirds was sufficient for mitochondrial localization. A HopG1-GFP fusion lacking HopG1’s N-terminal 13 amino acids was not localized to the mitochondria reflecting the importance of the N-terminus for targeting. Constitutive expression of HopG1 in Arabidopsis thaliana, Nicotiana tabacum (tobacco) and Lycopersicon esculentum (tomato) dramatically alters plant development resulting in dwarfism, increased branching and infertility. Constitutive expression of HopG1 in planta leads to reduced respiration rates and an increased basal level of reactive oxygen species. These findings suggest that HopG1’s target is mitochondrial and that effector/target interaction promotes disease by disrupting mitochondrial functions. PMID:19863557

Rhizosphere Microbiome Recruited from a Suppressive Compost Improves Plant Fitness and Increases Protection against Vascular Wilt Pathogens of Tomato

PubMed Central

Antoniou, Anastasis; Tsolakidou, Maria-Dimitra; Stringlis, Ioannis A.; Pantelides, Iakovos S.

2017-01-01

Suppressive composts represent a sustainable approach to combat soilborne plant pathogens and an alternative to the ineffective chemical fungicides used against those. Nevertheless, suppressiveness to plant pathogens and reliability of composts are often inconsistent with unpredictable effects. While suppressiveness is usually attributed to the compost’s microorganisms, the mechanisms governing microbial recruitment by the roots and the composition of selected microbial communities are not fully elucidated. Herein, the purpose of the study was to evaluate the impact of a compost on tomato plant growth and its suppressiveness against Fusarium oxysporum f. sp. lycopersici (Foxl) and Verticillium dahliae (Vd). First, growth parameters of tomato plants grown in sterile peat-based substrates including 20 and 30% sterile compost (80P/20C-ST and 70P/30C-ST) or non-sterile compost (80P/20C and 70P/30C) were evaluated in a growth room experiment. Plant height, total leaf surface, and fresh and dry weight of plants grown in the non-sterile compost mixes were increased compared to the plants grown in the sterile compost substrates, indicating the plant growth promoting activity of the compost’s microorganisms. Subsequently, compost’s suppressiveness against Foxl and Vd was evaluated with pathogenicity experiments on tomato plants grown in 70P/30C-ST and 70P/30C substrates. Disease intensity was significantly less in plants grown in the non-sterile compost than in those grown in the sterile compost substrate; AUDPC was 2.3- and 1.4-fold less for Foxl and Vd, respectively. Moreover, fungal quantification in planta demonstrated reduced colonization in plants grown in the non-sterile mixture. To further investigate these findings, we characterized the culturable microbiome attracted by the roots compared to the unplanted compost. Bacteria and fungi isolated from unplanted compost and the rhizosphere of plants were sequence-identified. Community-level analysis revealed

Evolutionary Agroecology: the potential for cooperative, high density, weed-suppressing cereals.

PubMed

Weiner, Jacob; Andersen, Sven B; Wille, Wibke K-M; Griepentrog, Hans W; Olsen, Jannie M

2010-09-01

Evolutionary theory can be applied to improve agricultural yields and/or sustainability, an approach we call Evolutionary Agroecology. The basic idea is that plant breeding is unlikely to improve attributes already favored by millions of years of natural selection, whereas there may be unutilized potential in selecting for attributes that increase total crop yield but reduce plants' individual fitness. In other words, plant breeding should be based on group selection. We explore this approach in relation to crop-weed competition, and argue that it should be possible to develop high density cereals that can utilize their initial size advantage over weeds to suppress them much better than under current practices, thus reducing or eliminating the need for chemical or mechanical weed control. We emphasize the role of density in applying group selection to crops: it is competition among individuals that generates the 'Tragedy of the Commons', providing opportunities to improve plant production by selecting for attributes that natural selection would not favor. When there is competition for light, natural selection of individuals favors a defensive strategy of 'shade avoidance', but a collective, offensive 'shading' strategy could increase weed suppression and yield in the high density, high uniformity cropping systems we envision.

A novel Meloidogyne enterolobii effector MeTCTP promotes parasitism by suppressing programmed cell death in host plants.

PubMed

Zhuo, Kan; Chen, Jiansong; Lin, Borong; Wang, Jing; Sun, Fengxia; Hu, Lili; Liao, Jinling

2017-01-01

Meloidogyne enterolobii is one of the most important plant-parasitic nematodes that can overcome the Mi-1 resistance gene and damage many economically important crops. Translationally controlled tumour protein (TCTP) is a multifunctional protein that exists in various eukaryotes and plays an important role in parasitism. In this study, a novel M. enterolobii TCTP effector, named MeTCTP, was identified and functionally characterized. MeTCTP was specifically expressed within the dorsal gland and was up-regulated during M. enterolobii parasitism. Transient expression of MeTCTP in protoplasts from tomato roots showed that MeTCTP was localized in the cytoplasm of the host cells. Transgenic Arabidopsis thaliana plants overexpressing MeTCTP were more susceptible to M. enterolobii infection than wild-type plants in a dose-dependent manner. By contrast, in planta RNA interference (RNAi) targeting MeTCTP suppressed the expression of MeTCTP in infecting nematodes and attenuated their parasitism. Furthermore, MeTCTP could suppress programmed cell death triggered by the pro-apoptotic protein BAX. These results demonstrate that MeTCTP is a novel plant-parasitic nematode effector that promotes parasitism, probably by suppressing programmed cell death in host plants. © 2016 BSPP and John Wiley & Sons Ltd.

Homologous RXLR effectors from Hyaloperonospora arabidopsidis and Phytophthora sojae suppress immunity in distantly related plants.

PubMed

Anderson, Ryan G; Casady, Megan S; Fee, Rachel A; Vaughan, Martha M; Deb, Devdutta; Fedkenheuer, Kevin; Huffaker, Alisa; Schmelz, Eric A; Tyler, Brett M; McDowell, John M

2012-12-01

Diverse pathogens secrete effector proteins into plant cells to manipulate host cellular processes. Oomycete pathogens contain large complements of predicted effector genes defined by an RXLR host cell entry motif. The genome of Hyaloperonospora arabidopsidis (Hpa, downy mildew of Arabidopsis) contains at least 134 candidate RXLR effector genes. Only a small subset of these genes is conserved in related oomycetes from the Phytophthora genus. Here, we describe a comparative functional characterization of the Hpa RXLR effector gene HaRxL96 and a homologous gene, PsAvh163, from the Glycine max (soybean) pathogen Phytophthora sojae. HaRxL96 and PsAvh163 are induced during the early stages of infection and carry a functional RXLR motif that is sufficient for protein uptake into plant cells. Both effectors can suppress immune responses in soybean. HaRxL96 suppresses immunity in Nicotiana benthamiana, whereas PsAvh163 induces an HR-like cell death response in Nicotiana that is dependent on RAR1 and Hsp90.1. Transgenic Arabidopsis plants expressing HaRxL96 or PsAvh163 exhibit elevated susceptibility to virulent and avirulent Hpa, as well as decreased callose deposition in response to non-pathogenic Pseudomonas syringae. Both effectors interfere with defense marker gene induction, but do not affect salicylic acid biosynthesis. Together, these experiments demonstrate that evolutionarily conserved effectors from different oomycete species can suppress immunity in plant species that are divergent from the source pathogen's host. © 2012 The Authors. The Plant Journal © 2012 Blackwell Publishing Ltd.

Effects of three fire-suppressant foams on the germination and physiological responses of plants.

PubMed

Song, Uhram; Mun, Saeromi; Waldman, Bruce; Lee, Eun Ju

2014-10-01

Suppressant foams used to fight forest fires may leave residual effects on surviving biota that managers need to consider prior to using them. We examined how three fire-suppressant foams (FSFs) (Forexpan S, Phos-Chek-WD881, and Silv-ex) affected seed germination and physiological responses of three plant species. Exposure to FSFs, whether in diluted concentrations or those typical in the field, reduced final germination percentages of seeds grown in petri dishes and within growth chambers. However, the FSFs did not cause total germination failure in any treatment. Inhibition of germination increased with longer exposure times, but only to diluted FSF solutions. Unlike in the laboratory experiments, none of the three FSFs affected seedling emergence when tested in field conditions. Further, we found no evidence of long-term phytotoxic effects on antioxidant enzyme activity nor chlorophyll content of the plant saplings. Therefore, although the three FSFs showed evidence of phytotoxicity to plants in laboratory tests, their actual impact on terrestrial ecosystems may be minimal. We suggest that the benefits of using these FSFs to protect plants in threatened forest ecosystems outweigh their minor risks.

Effects of Three Fire-Suppressant Foams on the Germination and Physiological Responses of Plants

NASA Astrophysics Data System (ADS)

Song, Uhram; Mun, Saeromi; Waldman, Bruce; Lee, Eun Ju

2014-10-01

Suppressant foams used to fight forest fires may leave residual effects on surviving biota that managers need to consider prior to using them. We examined how three fire-suppressant foams (FSFs) (Forexpan S, Phos-Chek-WD881, and Silv-ex) affected seed germination and physiological responses of three plant species. Exposure to FSFs, whether in diluted concentrations or those typical in the field, reduced final germination percentages of seeds grown in petri dishes and within growth chambers. However, the FSFs did not cause total germination failure in any treatment. Inhibition of germination increased with longer exposure times, but only to diluted FSF solutions. Unlike in the laboratory experiments, none of the three FSFs affected seedling emergence when tested in field conditions. Further, we found no evidence of long-term phytotoxic effects on antioxidant enzyme activity nor chlorophyll content of the plant saplings. Therefore, although the three FSFs showed evidence of phytotoxicity to plants in laboratory tests, their actual impact on terrestrial ecosystems may be minimal. We suggest that the benefits of using these FSFs to protect plants in threatened forest ecosystems outweigh their minor risks.

Nematode suppression and growth stimulation in corn plants (Zea mays L.) irrigated with domestic effluent.

PubMed

Barros, Kenia Kelly; do Nascimento, Clístenes Williams Araújo; Florencio, Lourdinha

2012-01-01

Treated wastewater has great potential for agricultural use due to its concentrations of nutrients and organic matter, which are capable of improving soil characteristics. Additionally, effluents can induce suppression of plant diseases caused by soil pathogens. This study evaluates the effect of irrigation with effluent in a UASB reactor on maize (Zea mays L.) development and on suppression of the diseases caused by nematodes of the genus Meloidogyne. Twelve lysimeters of 1 m(3) each were arranged in a completely randomized design, with four treatments and three replicates. The following treatments were used: T1 (W+I), irrigation with water and infestation with nematodes; T2 (W+I+NPK), irrigation with water, infestation with nematodes and fertilization with nitrogen (N), phosphorus (P) and potassium (K); T3 (E+I), irrigation with effluent and infestation with nematodes; and T4 (E+I+P), irrigation with effluent, infestation with nematodes and fertilization with phosphorus. The plants irrigated with the effluent plus the phosphorus fertilizer had better growth and productivity and were more resistant to the disease symptoms caused by the nematodes. The suppression levels may have been due to the higher levels of Zn and NO(3)(-) found in the leaf tissue of the plants irrigated with the effluent and phosphorus fertilizer.

A bacterial cysteine protease effector protein interferes with photosynthesis to suppress plant innate immune responses.

PubMed

Rodríguez-Herva, José J; González-Melendi, Pablo; Cuartas-Lanza, Raquel; Antúnez-Lamas, María; Río-Alvarez, Isabel; Li, Ziduo; López-Torrejón, Gema; Díaz, Isabel; Del Pozo, Juan C; Chakravarthy, Suma; Collmer, Alan; Rodríguez-Palenzuela, Pablo; López-Solanilla, Emilia

2012-05-01

The bacterial pathogen Pseudomonas syringae pv tomato DC3000 suppresses plant innate immunity with effector proteins injected by a type III secretion system (T3SS). The cysteine protease effector HopN1, which reduces the ability of DC3000 to elicit programmed cell death in non-host tobacco, was found to also suppress the production of defence-associated reactive oxygen species (ROS) and callose when delivered by Pseudomonas fluorescens heterologously expressing a P. syringae T3SS. Purified His(6) -tagged HopN1 was used to identify tomato PsbQ, a member of the oxygen evolving complex of photosystem II (PSII), as an interacting protein. HopN1 localized to chloroplasts and both degraded PsbQ and inhibited PSII activity in chloroplast preparations, whereas a HopN1(D299A) non-catalytic mutant lost these abilities. Gene silencing of NtPsbQ in tobacco compromised ROS production and programmed cell death by DC3000. Our data reveal PsbQ as a contributor to plant immunity responses and a target for pathogen suppression. © 2012 Blackwell Publishing Ltd.

Are Local Filters Blind to Provenance? Ant Seed Predation Suppresses Exotic Plants More than Natives

PubMed Central

Pearson, Dean E.; Icasatti, Nadia S.; Hierro, Jose L.; Bird, Benjamin J.

2014-01-01

The question of whether species’ origins influence invasion outcomes has been a point of substantial debate in invasion ecology. Theoretically, colonization outcomes can be predicted based on how species’ traits interact with community filters, a process presumably blind to species’ origins. Yet, exotic plant introductions commonly result in monospecific plant densities not commonly seen in native assemblages, suggesting that exotic species may respond to community filters differently than natives. Here, we tested whether exotic and native species differed in their responses to a local community filter by examining how ant seed predation affected recruitment of eighteen native and exotic plant species in central Argentina. Ant seed predation proved to be an important local filter that strongly suppressed plant recruitment, but ants suppressed exotic recruitment far more than natives (89% of exotic species vs. 22% of natives). Seed size predicted ant impacts on recruitment independent of origins, with ant preference for smaller seeds resulting in smaller seeded plant species being heavily suppressed. The disproportionate effects of provenance arose because exotics had generally smaller seeds than natives. Exotics also exhibited greater emergence and earlier peak emergence than natives in the absence of ants. However, when ants had access to seeds, these potential advantages of exotics were negated due to the filtering bias against exotics. The differences in traits we observed between exotics and natives suggest that higher-order introduction filters or regional processes preselected for certain exotic traits that then interacted with the local seed predation filter. Our results suggest that the interactions between local filters and species traits can predict invasion outcomes, but understanding the role of provenance will require quantifying filtering processes at multiple hierarchical scales and evaluating interactions between filters. PMID:25099535

A novel nematode effector suppresses plant immunity by activating host reactive oxygen species-scavenging system.

PubMed

Lin, Borong; Zhuo, Kan; Chen, Shiyan; Hu, Lili; Sun, Longhua; Wang, Xiaohong; Zhang, Lian-Hui; Liao, Jinling

2016-02-01

Evidence is emerging that plant-parasitic nematodes can secrete effectors to interfere with the host immune response, but it remains unknown how these effectors can conquer host immune responses. Here, we depict a novel effector, MjTTL5, that could suppress plant immune response. Immunolocalization and transcriptional analyses showed that MjTTL5 is expressed specifically within the subventral gland of Meloidogyne javanica and up-regulated in the early parasitic stage of the nematode. Transgenic Arabidopsis lines expressing MjTTL5 were significantly more susceptible to M. javanica infection than wild-type plants, and vice versa, in planta silencing of MjTTL5 substantially increased plant resistance to M. javanica. Yeast two-hybrid, coimmunoprecipitation and bimolecular fluorescent complementation assays showed that MjTTL5 interacts specifically with Arabidopsis ferredoxin : thioredoxin reductase catalytic subunit (AtFTRc), a key component of host antioxidant system. The expression of AtFTRc is induced by the infection of M. javanica. Interaction between AtFTRc and MjTTL could drastically increase host reactive oxygen species-scavenging activity, and result in suppression of plant basal defenses and attenuation of host resistance to the nematode infection. Our results demonstrate that the host ferredoxin : thioredoxin system can be exploited cunningly by M. javanica, revealing a novel mechanism utilized by plant-parasitic nematodes to subjugate plant innate immunity and thereby promoting parasitism. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Ralstonia solanacearum Type III Effector RipAY Is a Glutathione-Degrading Enzyme That Is Activated by Plant Cytosolic Thioredoxins and Suppresses Plant Immunity.

PubMed

Mukaihara, Takafumi; Hatanaka, Tadashi; Nakano, Masahito; Oda, Kenji

2016-04-12

The plant pathogen Ralstonia solanacearum uses a large repertoire of type III effector proteins to succeed in infection. To clarify the function of effector proteins in host eukaryote cells, we expressed effectors in yeast cells and identified seven effector proteins that interfere with yeast growth. One of the effector proteins, RipAY, was found to share homology with the ChaC family proteins that function as γ-glutamyl cyclotransferases, which degrade glutathione (GSH), a tripeptide that plays important roles in the plant immune system. RipAY significantly inhibited yeast growth and simultaneously induced rapid GSH depletion when expressed in yeast cells. The in vitro GSH degradation activity of RipAY is specifically activated by eukaryotic factors in the yeast and plant extracts. Biochemical purification of the yeast protein identified that RipAY is activated by thioredoxin TRX2. On the other hand, RipAY was not activated by bacterial thioredoxins. Interestingly, RipAY was activated by plant h-type thioredoxins that exist in large amounts in the plant cytosol, but not by chloroplastic m-, f-, x-, y- and z-type thioredoxins, in a thiol-independent manner. The transient expression of RipAY decreased the GSH level in plant cells and affected the flg22-triggered production of reactive oxygen species (ROS) and expression of pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) marker genes in Nicotiana benthamiana leaves. These results indicate that RipAY is activated by host cytosolic thioredoxins and degrades GSH specifically in plant cells to suppress plant immunity. Ralstonia solanacearum is the causal agent of bacterial wilt disease of plants. This pathogen injects virulence effector proteins into host cells to suppress disease resistance responses of plants. In this article, we report a biochemical activity of R. solanacearum effector protein RipAY. RipAY can degrade GSH, a tripeptide that plays important roles in the plant immune system, with

A Phytophthora sojae effector PsCRN63 forms homo-/hetero-dimers to suppress plant immunity via an inverted association manner.

PubMed

Li, Qi; Zhang, Meixiang; Shen, Danyu; Liu, Tingli; Chen, Yanyu; Zhou, Jian-Min; Dou, Daolong

2016-05-31

Oomycete pathogens produce a large number of effectors to promote infection. Their mode of action are largely unknown. Here we show that a Phytophthora sojae effector, PsCRN63, suppresses flg22-induced expression of FRK1 gene, a molecular marker in pathogen-associated molecular patterns (PAMP)-triggered immunity (PTI). However, PsCRN63 does not suppress upstream signaling events including flg22-induced MAPK activation and BIK1 phosphorylation, indicating that it acts downstream of MAPK cascades. The PsCRN63-transgenic Arabidopsis plants showed increased susceptibility to bacterial pathogen Pseudomonas syringae pathovar tomato (Pst) DC3000 and oomycete pathogen Phytophthora capsici. The callose deposition were suppressed in PsCRN63-transgenic plants compared with the wild-type control plants. Genes involved in PTI were also down-regulated in PsCRN63-transgenic plants. Interestingly, we found that PsCRN63 forms an dimer that is mediated by inter-molecular interactions between N-terminal and C-terminal domains in an inverted association manner. Furthermore, the N-terminal and C-terminal domains required for the dimerization are widely conserved among CRN effectors, suggesting that homo-/hetero-dimerization of Phytophthora CRN effectors is required to exert biological functions. Indeed, the dimerization was required for PTI suppression and cell death-induction activities of PsCRN63.

SacB-SacR gene cassette as the negative selection marker to suppress Agrobacterium overgrowth in Agrobacterium-mediated plant transformation

USDA-ARS?s Scientific Manuscript database

Agrobacterium overgrowth is a common problem in Agrobacterium-mediated plant transformation. To suppress the Agrobacterium overgrowth, various antibiotics have been used during plant tissue culture steps. The antibiotics are expensive and may adversely affect plant cell differentiation and reduce ...

Silencing of tryptamine biosynthesis for production of nonnatural alkaloids in plant culture.

PubMed

Runguphan, Weerawat; Maresh, Justin J; O'Connor, Sarah E

2009-08-18

Natural products have long served as both a source and inspiration for pharmaceuticals. Modifying the structure of a natural product often improves the biological activity of the compound. Metabolic engineering strategies to ferment "unnatural" products have been enormously successful in microbial organisms. However, despite the importance of plant derived natural products, metabolic engineering strategies to yield unnatural products from complex, lengthy plant pathways have not been widely explored. Here, we show that RNA mediated suppression of tryptamine biosynthesis in Catharanthus roseus hairy root culture eliminates all production of monoterpene indole alkaloids, a class of natural products derived from two starting substrates, tryptamine and secologanin. To exploit this chemically silent background, we introduced an unnatural tryptamine analog to the production media and demonstrated that the silenced plant culture could produce a variety of novel products derived from this unnatural starting substrate. The novel alkaloids were not contaminated by the presence of the natural alkaloids normally present in C. roseus. Suppression of tryptamine biosynthesis therefore did not appear to adversely affect expression of downstream biosynthetic enzymes. Targeted suppression of substrate biosynthesis therefore appears to be a viable strategy for programming a plant alkaloid pathway to more effectively produce desirable unnatural products. Moreover, although tryptamine is widely found among plants, this silenced line demonstrates that tryptamine does not play an essential role in growth or development in C. roseus root culture. Silencing the biosynthesis of an early starting substrate enhances our ability to harness the rich diversity of plant based natural products.

Insect herbivory and plant adaptation in an early successional community.

PubMed

Agrawal, Anurag A; Hastings, Amy P; Fines, Daniel M; Bogdanowicz, Steve; Huber, Meret

2018-05-01

To address the role of insect herbivores in adaptation of plant populations and the persistence of selection through succession, we manipulated herbivory in a long-term field experiment. We suppressed insects in half of 16 plots over nine years and examined the genotypic structure and chemical defense of common dandelion (Taraxacum officinale), a naturally colonizing perennial apomictic plant. Insect suppression doubled dandelion abundance in the first few years, but had negligible effects thereafter. Using microsatellite DNA markers, we genotyped >2500 plants and demonstrate that insect suppression altered the genotypic composition of plots in both sampling years. Phenotypic and genotypic estimates of defensive terpenes and phenolics from the field plots allowed us to infer phenotypic plasticity and the response of dandelion populations to insect-mediated natural selection. The effects of insect suppression on plant chemistry were, indeed, driven both by plasticity and plant genotypic identity. In particular, di-phenolic inositol esters were more abundant in plots exposed to herbivory (due to the genotypic composition of the plots) and were also induced in response to herbivory. This field experiment thus demonstrates evolutionary sorting of plant genotypes in response to insect herbivores that was in same direction as the plastic defensive response within genotypes. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

Natural Gas Processing Plants in the United States: 2010 Update

EIA Publications

2011-01-01

This special report presents an analysis of natural gas processing plants in the United States as of 2009 and highlights characteristics of this segment of the industry. The purpose of the paper is to examine the role of natural gas processing plants in the natural gas supply chain and to provide an overview and summary of processing plant characteristics in the United States, such as locations, capacities, and operations.

Arsenic-phosphorus interactions in the soil-plant-microbe system: Dynamics of uptake, suppression and toxicity to plants.

PubMed

Anawar, Hossain M; Rengel, Zed; Damon, Paul; Tibbett, Mark

2018-02-01

High arsenic (As) concentrations in the soil, water and plant systems can pose a direct health risk to humans and ecosystems. Phosphate (Pi) ions strongly influence As availability in soil, its uptake and toxicity to plants. Better understanding of As(V)-Pi interactions in soils and plants will facilitate a potential remediation strategy for As contaminated soils, reducing As uptake by crop plants and toxicity to human populations via manipulation of soil Pi content. However, the As(V)-Pi interactions in soil-plant systems are complex, leading to contradictory findings among different studies. Therefore, this review investigates the role of soil type, soil properties, minerals, Pi levels in soil and plant, Pi transporters, mycorrhizal association and microbial activities on As-Pi interactions in soils and hydroponics, and uptake by plants, elucidate the key mechanisms, identify key knowledge gaps and recommend new research directions. Although Pi suppresses As uptake by plants in hydroponic systems, in soils it could either increase or decrease As availability and toxicity to plants depending on the soil types, properties and charge characteristics. In soil, As(V) availability is typically increased by the addition of Pi. At the root surface, the Pi transport system has high affinity for Pi over As(V). However, Pi concentration in plant influences the As transport from roots to shoots. Mycorrhizal association may reduce As uptake via a physiological shift to the mycorrhizal uptake pathway, which has a greater affinity for Pi over As(V) than the root epidermal uptake pathway. Copyright © 2017 Elsevier Ltd. All rights reserved.

Direct and indirect plant defenses are not suppressed by endosymbionts of a specialist root herbivore

USDA-ARS?s Scientific Manuscript database

Insect endosymbionts influence many important metabolic and developmental processes of their host. It has been speculated that they may also help to manipulate and suppress plant defenses to the benefit of herbivores. Recently, endosymbionts of the root herbivore Diabrotica virgifera virgifera have ...

Antibiotic production by soil bacteria: diversity, activity and natural functions

USDA-ARS?s Scientific Manuscript database

The living components of soils, the micro- and macrobiota, play an essential role in several life support functions as they enable soils to recycle nutrients, inactive contaminants, suppress plant pathogens and serve as a suitable substrate for plant growth. Beneficial bacteria occur naturally in s...

Natural selection on plant physiological traits in an urban environment

NASA Astrophysics Data System (ADS)

Lambrecht, Susan C.; Mahieu, Stephanie; Cheptou, Pierre-Olivier

2016-11-01

Current rates of urbanization are creating new opportunities for studying urban plant ecology, but our knowledge of urban plant physiology lags behind that of other ecosystems. Moreover, higher temperatures, elevated CO2, and increased inorganic nitrogen deposition along with altered moisture regimes of urban as compared to rural areas creates a compelling analog for studying adaptations of plants to climate change. We grew plants under common conditions in a greenhouse to determine whether populations of Crepis sancta (Asteraceae) differed in phenological, morphological, and physiological traits. We also used a field experiment to test for natural selection on these traits in urban Montpellier, France. Urban plants flowered and senesced later than rural plants, and natural selection favored later phenology in the urban habitat. Natural selection also favored larger plants with more leaves, and increased photosynthesis and leaf nitrogen concentration. Ours is the first study to document selection on plant functional traits in an urban habitat and, as such, advances our understanding of urban plant ecology and possible adaptations to climate change.

Nitrate dynamics in natural plants: insights based on the concentration and natural isotope abundances of tissue nitrate

PubMed Central

Liu, Xue-Yan; Koba, Keisuke; Makabe, Akiko; Liu, Cong-Qiang

2014-01-01

The dynamics of nitrate (NO−3), a major nitrogen (N) source for natural plants, has been studied mostly through experimental N addition, enzymatic assay, isotope labeling, and genetic expression. However, artificial N supply may not reasonably reflect the N strategies in natural plants because NO−3 uptake and reduction may vary with external N availability. Due to abrupt application and short operation time, field N addition, and isotopic labeling hinder the elucidation of in situ NO−3-use mechanisms. The concentration and natural isotopes of tissue NO−3 can offer insights into the plant NO−3 sources and dynamics in a natural context. Furthermore, they facilitate the exploration of plant NO−3 utilization and its interaction with N pollution and ecosystem N cycles without disturbing the N pools. The present study was conducted to review the application of the denitrifier method for concentration and isotope analyses of NO−3 in plants. Moreover, this study highlights the utility and advantages of these parameters in interpreting NO−3 sources and dynamics in natural plants. We summarize the major sources and reduction processes of NO−3 in plants, and discuss the implications of NO−3 concentration in plant tissues based on existing data. Particular emphasis was laid on the regulation of soil NO−3 and plant ecophysiological functions in interspecific and intra-plant NO−3 variations. We introduce N and O isotope systematics of NO−3 in plants and discuss the principles and feasibilities of using isotopic enrichment and fractionation factors; the correlation between concentration and isotopes (N and O isotopes: δ18O and Δ17O); and isotope mass-balance calculations to constrain sources and reduction of NO−3 in possible scenarios for natural plants are deliberated. Finally, we offer a preliminary framework of intraplant δ18O-NO−3 variation, and summarize the uncertainties in using tissue NO−3 parameters to interpret plant NO−3 utilization

Nitrate dynamics in natural plants: insights based on the concentration and natural isotope abundances of tissue nitrate.

PubMed

Liu, Xue-Yan; Koba, Keisuke; Makabe, Akiko; Liu, Cong-Qiang

2014-01-01

The dynamics of nitrate (NO(-) 3), a major nitrogen (N) source for natural plants, has been studied mostly through experimental N addition, enzymatic assay, isotope labeling, and genetic expression. However, artificial N supply may not reasonably reflect the N strategies in natural plants because NO(-) 3 uptake and reduction may vary with external N availability. Due to abrupt application and short operation time, field N addition, and isotopic labeling hinder the elucidation of in situ NO(-) 3-use mechanisms. The concentration and natural isotopes of tissue NO(-) 3 can offer insights into the plant NO(-) 3 sources and dynamics in a natural context. Furthermore, they facilitate the exploration of plant NO(-) 3 utilization and its interaction with N pollution and ecosystem N cycles without disturbing the N pools. The present study was conducted to review the application of the denitrifier method for concentration and isotope analyses of NO(-) 3 in plants. Moreover, this study highlights the utility and advantages of these parameters in interpreting NO(-) 3 sources and dynamics in natural plants. We summarize the major sources and reduction processes of NO(-) 3 in plants, and discuss the implications of NO(-) 3 concentration in plant tissues based on existing data. Particular emphasis was laid on the regulation of soil NO(-) 3 and plant ecophysiological functions in interspecific and intra-plant NO(-) 3 variations. We introduce N and O isotope systematics of NO(-) 3 in plants and discuss the principles and feasibilities of using isotopic enrichment and fractionation factors; the correlation between concentration and isotopes (N and O isotopes: δ(18)O and Δ(17)O); and isotope mass-balance calculations to constrain sources and reduction of NO(-) 3 in possible scenarios for natural plants are deliberated. Finally, we offer a preliminary framework of intraplant δ(18)O-NO(-) 3 variation, and summarize the uncertainties in using tissue NO(-) 3 parameters to interpret

The Ustilago maydis Effector Pep1 Suppresses Plant Immunity by Inhibition of Host Peroxidase Activity

PubMed Central

Zechmann, Bernd; Hillmer, Morten; Doehlemann, Gunther

2012-01-01

The corn smut Ustilago maydis establishes a biotrophic interaction with its host plant maize. This interaction requires efficient suppression of plant immune responses, which is attributed to secreted effector proteins. Previously we identified Pep1 (Protein essential during penetration-1) as a secreted effector with an essential role for U. maydis virulence. pep1 deletion mutants induce strong defense responses leading to an early block in pathogenic development of the fungus. Using cytological and functional assays we show that Pep1 functions as an inhibitor of plant peroxidases. At sites of Δpep1 mutant penetrations, H2O2 strongly accumulated in the cell walls, coinciding with a transcriptional induction of the secreted maize peroxidase POX12. Pep1 protein effectively inhibited the peroxidase driven oxidative burst and thereby suppresses the early immune responses of maize. Moreover, Pep1 directly inhibits peroxidases in vitro in a concentration-dependent manner. Using fluorescence complementation assays, we observed a direct interaction of Pep1 and the maize peroxidase POX12 in vivo. Functional relevance of this interaction was demonstrated by partial complementation of the Δpep1 mutant defect by virus induced gene silencing of maize POX12. We conclude that Pep1 acts as a potent suppressor of early plant defenses by inhibition of peroxidase activity. Thus, it represents a novel strategy for establishing a biotrophic interaction. PMID:22589719

Fungal Community Structure in Disease Suppressive Soils Assessed by 28S LSU Gene Sequencing

PubMed Central

Penton, C. Ryan; Gupta, V. V. S. R.; Tiedje, James M.; Neate, Stephen M.; Ophel-Keller, Kathy; Gillings, Michael; Harvey, Paul; Pham, Amanda; Roget, David K.

2014-01-01

Natural biological suppression of soil-borne diseases is a function of the activity and composition of soil microbial communities. Soil microbe and phytopathogen interactions can occur prior to crop sowing and/or in the rhizosphere, subsequently influencing both plant growth and productivity. Research on suppressive microbial communities has concentrated on bacteria although fungi can also influence soil-borne disease. Fungi were analyzed in co-located soils ‘suppressive’ or ‘non-suppressive’ for disease caused by Rhizoctonia solani AG 8 at two sites in South Australia using 454 pyrosequencing targeting the fungal 28S LSU rRNA gene. DNA was extracted from a minimum of 125 g of soil per replicate to reduce the micro-scale community variability, and from soil samples taken at sowing and from the rhizosphere at 7 weeks to cover the peak Rhizoctonia infection period. A total of ∼994,000 reads were classified into 917 genera covering 54% of the RDP Fungal Classifier database, a high diversity for an alkaline, low organic matter soil. Statistical analyses and community ordinations revealed significant differences in fungal community composition between suppressive and non-suppressive soil and between soil type/location. The majority of differences associated with suppressive soils were attributed to less than 40 genera including a number of endophytic species with plant pathogen suppression potentials and mycoparasites such as Xylaria spp. Non-suppressive soils were dominated by Alternaria, Gibberella and Penicillum. Pyrosequencing generated a detailed description of fungal community structure and identified candidate taxa that may influence pathogen-plant interactions in stable disease suppression. PMID:24699870

Evaluation of an antibiotic producing strain of Pseudomonas flourescens for suppression of plant-parasitic nematodes

USDA-ARS?s Scientific Manuscript database

The antibiotic 2,4-diacetylphloroglucinol (DAPG), produced by some strains of Pseudomonas spp., is involved in suppression of several fungal root pathogens as well as plant-parasitic nematodes. The primary objective of this study was to determine whether Wood1R, a D-genotype strain of DAPG-producin...

Forage radish winter cover crop suppresses winter annual weeds in fall and before corn planting

USDA-ARS?s Scientific Manuscript database

Forage radish (Raphanus sativus L. var. longipinnatus) is a new winter cover crop in the Mid-Atlantic region. The objective of this project was to characterize the repeatability, amount, and duration of weed suppression during and after a fall-planted forage radish cover crop and to quantify the sub...

The novel GrCEP12 peptide from the plant-parasitic nematode Globodera rostochiensis suppresses flg22-mediated PTI.

PubMed

Chen, Shiyan; Chronis, Demosthenis; Wang, Xiaohong

2013-09-01

The potato cyst nematode Globodera rostochiensis is a biotrophic pathogen that secretes effector proteins into host root cells to promote successful plant parasitism. In addition to the role in generating within root tissue the feeding cells essential for nematode development, (1) nematode secreted effectors are becoming recognized as suppressors of plant immunity. (2)(-) (4) Recently we reported that the effector ubiquitin carboxyl extension protein (GrUBCEP12) from G. rostochiensis is processed into free ubiquitin and a 12-amino acid GrCEP12 peptide in planta. Transgenic potato lines overexpressing the derived GrCEP12 peptide showed increased susceptibility to G. rostochiensis and to an unrelated bacterial pathogen Streptomyces scabies, suggesting that GrCEP12 has a role in suppressing host basal defense or possibly pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) during the parasitic interaction. (3) To determine if GrCEP12 functions as a PTI suppressor we evaluated whether GrCEP12 suppresses flg22-induced PTI responses in Nicotiana benthamiana. Interestingly, we found that transient expression of GrCEP12 in N. benthamiana leaves suppressed reactive oxygen species (ROS) production and the induction of two PTI marker genes triggered by the bacterial PAMP flg22, providing direct evidence that GrCEP12 indeed has an activity in PTI suppression.

Metabolic engineering of microorganisms for the synthesis of plant natural products.

PubMed

Marienhagen, Jan; Bott, Michael

2013-01-20

Of more than 200,000 plant natural products known to date, many demonstrate important pharmacological activities or are of biotechnological significance. However, isolation from natural sources is usually limited by low abundance and environmental, seasonal as well as regional variation, whereas total chemical synthesis is typically commercially unfeasible considering the complex structures of most plant natural products. With advances in DNA sequencing and recombinant DNA technology many of the biosynthetic pathways responsible for the production of these valuable compounds have been elucidated, offering the opportunity of a functional integration of biosynthetic pathways in suitable microorganisms. This approach offers promise to provide sufficient quantities of the desired plant natural products from inexpensive renewable resources. This review covers recent advancements in the metabolic engineering of microorganisms for the production of plant natural products such as isoprenoids, phenylpropanoids and alkaloids, and highlights general approaches and strategies to gain access to the rich biochemical diversity of plants by employing the biosynthetic power of microorganisms. Copyright © 2012 Elsevier B.V. All rights reserved.

Avian use of natural versus planted woodlands in eastern South Dakota, USA

USGS Publications Warehouse

Bakker, K.K.; Higgins, K.F.

2003-01-01

We compared avian use of naturally occurring and planted woodlands in eastern South Dakota, USA, to evaluate whether planted woodlands support the same avian communities as natural woodlands. A stratified cluster sample was used to randomly select 307 public areas in which to survey planted (n = 425) and natural (n = 99) woodland patches. Eighty-five species of birds were detected in eastern South Dakota woodlands, 36 of which occurred in ??? 5 of 524 patches surveyed. The probability of occurrence for 8 of 13 woodland-obligate species was significantly greater in natural woodland habitats than in planted woodland habitats. Four of these species breed in relatively high numbers in eastern South Dakota. Only one woodland-obligate occurred less frequently in natural woodlands. Probability of occurrence for 6 edge and generalist species, including the brown-headed cowbird (Molothrus ater [Boddaert]), was significantly higher in planted woodlands. The avian community of planted woodlands was dominated by edge and generalist species. The homogeneous vegetation structure typical of planted woodlands does not appear to provide the habitat characteristics needed by woodland-obligate birds. We conclude that planted woodlands do not support significant numbers of woodland-obligate species and may negatively impact grassland-nesting birds by attracting edge and generalist bird species and predators into previously treeless habitats. Planted woodlands cannot be considered equal replacement habitats for natural woodland patches when managing for nongame woodland bird species. However, the preservation and maintenance of natural woodlands is critical for woodland-obligate species diversity in the northern Great Plains.

PlantNATsDB: a comprehensive database of plant natural antisense transcripts.

PubMed

Chen, Dijun; Yuan, Chunhui; Zhang, Jian; Zhang, Zhao; Bai, Lin; Meng, Yijun; Chen, Ling-Ling; Chen, Ming

2012-01-01

Natural antisense transcripts (NATs), as one type of regulatory RNAs, occur prevalently in plant genomes and play significant roles in physiological and pathological processes. Although their important biological functions have been reported widely, a comprehensive database is lacking up to now. Consequently, we constructed a plant NAT database (PlantNATsDB) involving approximately 2 million NAT pairs in 69 plant species. GO annotation and high-throughput small RNA sequencing data currently available were integrated to investigate the biological function of NATs. PlantNATsDB provides various user-friendly web interfaces to facilitate the presentation of NATs and an integrated, graphical network browser to display the complex networks formed by different NATs. Moreover, a 'Gene Set Analysis' module based on GO annotation was designed to dig out the statistical significantly overrepresented GO categories from the specific NAT network. PlantNATsDB is currently the most comprehensive resource of NATs in the plant kingdom, which can serve as a reference database to investigate the regulatory function of NATs. The PlantNATsDB is freely available at http://bis.zju.edu.cn/pnatdb/.

Plant-Soil Feedback: Bridging Natural and Agricultural Sciences.

PubMed

Mariotte, Pierre; Mehrabi, Zia; Bezemer, T Martijn; De Deyn, Gerlinde B; Kulmatiski, Andrew; Drigo, Barbara; Veen, G F Ciska; van der Heijden, Marcel G A; Kardol, Paul

2018-02-01

In agricultural and natural systems researchers have demonstrated large effects of plant-soil feedback (PSF) on plant growth. However, the concepts and approaches used in these two types of systems have developed, for the most part, independently. Here, we present a conceptual framework that integrates knowledge and approaches from these two contrasting systems. We use this integrated framework to demonstrate (i) how knowledge from complex natural systems can be used to increase agricultural resource-use efficiency and productivity and (ii) how research in agricultural systems can be used to test hypotheses and approaches developed in natural systems. Using this framework, we discuss avenues for new research toward an ecologically sustainable and climate-smart future. Copyright © 2017 Elsevier Ltd. All rights reserved.

Naturalization of European plants on other continents: The role of donor habitats.

PubMed

Kalusová, Veronika; Chytrý, Milan; van Kleunen, Mark; Mucina, Ladislav; Dawson, Wayne; Essl, Franz; Kreft, Holger; Pergl, Jan; Weigelt, Patrick; Winter, Marten; Pyšek, Petr

2017-12-26

The success of European plant species as aliens worldwide is thought to reflect their association with human-disturbed environments. However, an explicit test including all human-made, seminatural and natural habitat types of Europe, and their contributions as donor habitats of naturalized species to the rest of the globe, has been missing. Here we combine two databases, the European Vegetation Checklist and the Global Naturalized Alien Flora, to assess how human influence in European habitats affects the probability of naturalization of their plant species on other continents. A total of 9,875 native European vascular plant species were assigned to 39 European habitat types; of these, 2,550 species have become naturalized somewhere in the world. Species that occur in both human-made habitats and seminatural or natural habitats in Europe have the highest probability of naturalization (64.7% and 64.5% of them have naturalized). Species associated only with human-made or seminatural habitats still have a significantly higher probability of becoming naturalized (41.7% and 28.6%, respectively) than species confined to natural habitats (19.4%). Species associated with arable land and human settlements were recorded as naturalized in the largest number of regions worldwide. Our findings highlight that plant species' association with native-range habitats disturbed by human activities, combined with broad habitat range, play an important role in shaping global patterns of plant invasions.

Risk in nuclear power plants due to natural hazard phenomena

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

Lu, S.C.

1995-12-01

For the safety of nuclear power plants, it is important to identify potential areas of vulnerabilities to internal as well as external events to which nuclear power plants are exposed. This paper summarizes the risk in nuclear power plants due to natural hazard phenomena such as earthquakes, winds and tornadoes, floods, etc. The reported results are based on a limited number of probabilistic risk assessments (PRAS) performed for a few of the operating nuclear power plants within the United States. The summary includes an importance ranking of various natural hazard phenomena based on their contribution to the plant risk alongmore » with insights observed from the PRA studies.« less

[Application of natural plant pigment in hair dyes].

PubMed

Hu, Yu-Li; Luo, Jiao-Yang; Zhao, Hong-Zheng; Zhang, Shan-Shan; Yang, Shi-Hai; Yang, Mei-Hua

2016-09-01

With the development of living condition, more and more people tend to show unique personality, thus hair dyes as hair cosmetics are highly favored. By the year 2012, the global sales of hair dye had exceeded $15 billion, with a sustained growth at a rate of 8%-10% annually. However, the harm caused by long-term use of hair dyes has aroused widespread public concern, so people begin to seek non-toxic or low toxic natural plant hair dyes. The types of commonly used hair dyes and the corresponding dyeing mechanisms were summarized in this manuscript, and the representative natural botanic dyes were listed. Thereafter, their effective fractions, constituents and application status were described. In addition, the values of botanic hair dyes and their broad market prospect were discussed. Finally, the problems that exist in the research and development of plant hair dyes were issued. This review may help to provide thought for developing novel, green and ecological natural plant hair dyes. Copyright© by the Chinese Pharmaceutical Association.

Naturally Occurring Fish Poisons from Plants

ERIC Educational Resources Information Center

Cannon, Jonathan G.; Burton, Robert A.; Wood, Steven G.; Owen, Noel L.

2004-01-01

The fish poisons derived from plants used throughout the world, not only as piscicides but also for a range of other uses, including insecticident and in folk medicines, is presented. The aim of this review is to provide a useful background for students interested in natural products.

Distinct regions of the Phytophthora essential effector Avh238 determine its function in cell death activation and plant immunity suppression.

PubMed

Yang, Bo; Wang, Qunqing; Jing, Maofeng; Guo, Baodian; Wu, Jiawei; Wang, Haonan; Wang, Yang; Lin, Long; Wang, Yan; Ye, Wenwu; Dong, Suomeng; Wang, Yuanchao

2017-04-01

Phytophthora pathogens secrete effectors to manipulate host innate immunity, thus facilitating infection. Among the RXLR effectors highly induced during Phytophthora sojae infection, Avh238 not only contributes to pathogen virulence but also triggers plant cell death. However, the detailed molecular basis of Avh238 functions remains largely unknown. We mapped the regions responsible for Avh238 functions in pathogen virulence and plant cell death induction using a strategy that combines investigation of natural variation and large-scale mutagenesis assays. The correlation between cellular localization and Avh238 functions was also evaluated. We found that the 79 th residue (histidine or leucine) of Avh238 determined its cell death-inducing activity, and that the 53 amino acids in its C-terminal region are responsible for promoting Phytophthora infection. Transient expression of Avh238 in Nicotiana benthamiana revealed that nuclear localization is essential for triggering cell death, while Avh238-mediated suppression of INF1-triggered cell death requires cytoplasmic localization. Our results demonstrate that a representative example of an essential Phytophthora RXLR effector can evolve to escape recognition by the host by mutating one nucleotide site, and can also retain plant immunosuppressive activity to enhance pathogen virulence in planta. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

The effector SPRYSEC-19 of Globodera rostochiensis suppresses CC-NB-LRR-mediated disease resistance in plants.

PubMed

Postma, Wiebe J; Slootweg, Erik J; Rehman, Sajid; Finkers-Tomczak, Anna; Tytgat, Tom O G; van Gelderen, Kasper; Lozano-Torres, Jose L; Roosien, Jan; Pomp, Rikus; van Schaik, Casper; Bakker, Jaap; Goverse, Aska; Smant, Geert

2012-10-01

The potato cyst nematode Globodera rostochiensis invades roots of host plants where it transforms cells near the vascular cylinder into a permanent feeding site. The host cell modifications are most likely induced by a complex mixture of proteins in the stylet secretions of the nematodes. Resistance to nematodes conferred by nucleotide-binding-leucine-rich repeat (NB-LRR) proteins usually results in a programmed cell death in and around the feeding site, and is most likely triggered by the recognition of effectors in stylet secretions. However, the actual role of these secretions in the activation and suppression of effector-triggered immunity is largely unknown. Here we demonstrate that the effector SPRYSEC-19 of G. rostochiensis physically associates in planta with the LRR domain of a member of the SW5 resistance gene cluster in tomato (Lycopersicon esculentum). Unexpectedly, this interaction did not trigger defense-related programmed cell death and resistance to G. rostochiensis. By contrast, agroinfiltration assays showed that the coexpression of SPRYSEC-19 in leaves of Nicotiana benthamiana suppresses programmed cell death mediated by several coiled-coil (CC)-NB-LRR immune receptors. Furthermore, SPRYSEC-19 abrogated resistance to Potato virus X mediated by the CC-NB-LRR resistance protein Rx1, and resistance to Verticillium dahliae mediated by an unidentified resistance in potato (Solanum tuberosum). The suppression of cell death and disease resistance did not require a physical association of SPRYSEC-19 and the LRR domains of the CC-NB-LRR resistance proteins. Altogether, our data demonstrated that potato cyst nematodes secrete effectors that enable the suppression of programmed cell death and disease resistance mediated by several CC-NB-LRR proteins in plants.

Plant Water Stress Affects Interactions Between an Invasive and a Naturalized Aphid Species on Cereal Crops.

PubMed

Foote, N E; Davis, T S; Crowder, D W; Bosque-Pérez, N A; Eigenbrode, S D

2017-06-01

In cereal cropping systems of the Pacific Northwestern United States (PNW), climate change is projected to increase the frequency of drought during summer months, which could increase water stress for crop plants. Yet, it remains uncertain how interactions between herbivore species are affected by drought stress. Here, interactions between two cereal aphids present in PNW cereal systems, Metopolophium festucae (Theobald) subsp. cerealium (a newly invasive species) and Rhopalosiphum padi L. (a naturalized species), were tested relative to wheat water stress. When aphids were confined in leaf cages on wheat, asymmetrical facilitation occurred; per capita fecundity of R. padi was increased by 46% when M. festucae cerealium was also present, compared to when only R. padi was present. Imposed water stress did not influence this interaction. When aphids were confined on whole wheat plants, asymmetrical competition occurred; cocolonization inhibited M. festucae cerealium population growth but did not affect R. padi population growth. Under conditions of plant water stress, however, the inhibitory effect of R. padi on M. festucae cerealium was not observed. We conclude that beneficial effects of cocolonization on R. padi are due to a localized plant response to M. festucae cerealium feeding, and that cocolonization of plants is likely to suppress M. festucae cerealium populations under ample water conditions, but not when plants are water stressed. This suggests that plant responses to water stress alter the outcome of competition between herbivore species, with implications for the structure of pest communities on wheat during periods of drought. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.

Suppression of RNA Silencing by a Plant DNA Virus Satellite Requires a Host Calmodulin-Like Protein to Repress RDR6 Expression

PubMed Central

Li, Fangfang; Huang, Changjun; Li, Zhenghe; Zhou, Xueping

2014-01-01

In plants, RNA silencing plays a key role in antiviral defense. To counteract host defense, plant viruses encode viral suppressors of RNA silencing (VSRs) that target different effector molecules in the RNA silencing pathway. Evidence has shown that plants also encode endogenous suppressors of RNA silencing (ESRs) that function in proper regulation of RNA silencing. The possibility that these cellular proteins can be subverted by viruses to thwart host defense is intriguing but has not been fully explored. Here we report that the Nicotiana benthamiana calmodulin-like protein Nbrgs-CaM is required for the functions of the VSR βC1, the sole protein encoded by the DNA satellite associated with the geminivirus Tomato yellow leaf curl China virus (TYLCCNV). Nbrgs-CaM expression is up-regulated by the βC1. Transgenic plants over-expressing Nbrgs-CaM displayed developmental abnormities reminiscent of βC1-associated morphological alterations. Nbrgs-CaM suppressed RNA silencing in an Agrobacterium infiltration assay and, when over-expressed, blocked TYLCCNV-induced gene silencing. Genetic evidence showed that Nbrgs-CaM mediated the βC1 functions in silencing suppression and symptom modulation, and was required for efficient virus infection. Moreover, the tobacco and tomato orthologs of Nbrgs-CaM also possessed ESR activity, and were induced by betasatellite to promote virus infection in these Solanaceae hosts. We further demonstrated that βC1-induced Nbrgs-CaM suppressed the production of secondary siRNAs, likely through repressing RNA-DEPENDENT RNA POLYMERASE 6 (RDR6) expression. RDR6-deficient N. benthamiana plants were defective in antiviral response and were hypersensitive to TYLCCNV infection. More significantly, TYLCCNV could overcome host range restrictions to infect Arabidopsis thaliana when the plants carried a RDR6 mutation. These findings demonstrate a distinct mechanism of VSR for suppressing PTGS through usurpation of a host ESR, and highlight an essential

Multiple Candidate Effectors from the Oomycete Pathogen Hyaloperonospora arabidopsidis Suppress Host Plant Immunity

PubMed Central

Fabro, Georgina; Steinbrenner, Jens; Coates, Mary; Ishaque, Naveed; Baxter, Laura; Studholme, David J.; Körner, Evelyn; Allen, Rebecca L.; Piquerez, Sophie J. M.; Rougon-Cardoso, Alejandra; Greenshields, David; Lei, Rita; Badel, Jorge L.; Caillaud, Marie-Cecile; Sohn, Kee-Hoon; Van den Ackerveken, Guido; Parker, Jane E.; Beynon, Jim; Jones, Jonathan D. G.

2011-01-01

Oomycete pathogens cause diverse plant diseases. To successfully colonize their hosts, they deliver a suite of effector proteins that can attenuate plant defenses. In the oomycete downy mildews, effectors carry a signal peptide and an RxLR motif. Hyaloperonospora arabidopsidis (Hpa) causes downy mildew on the model plant Arabidopsis thaliana (Arabidopsis). We investigated if candidate effectors predicted in the genome sequence of Hpa isolate Emoy2 (HaRxLs) were able to manipulate host defenses in different Arabidopsis accessions. We developed a rapid and sensitive screening method to test HaRxLs by delivering them via the bacterial type-three secretion system (TTSS) of Pseudomonas syringae pv tomato DC3000-LUX (Pst-LUX) and assessing changes in Pst-LUX growth in planta on 12 Arabidopsis accessions. The majority (∼70%) of the 64 candidates tested positively contributed to Pst-LUX growth on more than one accession indicating that Hpa virulence likely involves multiple effectors with weak accession-specific effects. Further screening with a Pst mutant (ΔCEL) showed that HaRxLs that allow enhanced Pst-LUX growth usually suppress callose deposition, a hallmark of pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI). We found that HaRxLs are rarely strong avirulence determinants. Although some decreased Pst-LUX growth in particular accessions, none activated macroscopic cell death. Fewer HaRxLs conferred enhanced Pst growth on turnip, a non-host for Hpa, while several reduced it, consistent with the idea that turnip's non-host resistance against Hpa could involve a combination of recognized HaRxLs and ineffective HaRxLs. We verified our results by constitutively expressing in Arabidopsis a sub-set of HaRxLs. Several transgenic lines showed increased susceptibility to Hpa and attenuation of Arabidopsis PTI responses, confirming the HaRxLs' role in Hpa virulence. This study shows TTSS screening system provides a useful tool to test whether candidate

A Virulence Essential CRN Effector of Phytophthora capsici Suppresses Host Defense and Induces Cell Death in Plant Nucleus.

PubMed

Mafurah, Joseph Juma; Ma, Huifei; Zhang, Meixiang; Xu, Jing; He, Feng; Ye, Tingyue; Shen, Danyu; Chen, Yanyu; Rajput, Nasir Ahmed; Dou, Daolong

2015-01-01

Phytophthora capsici is a soil-borne plant pathogen with a wide range of hosts. The pathogen secretes a large array of effectors during infection of host plants, including Crinkler (CRN) effectors. However, it remains largely unknown on the roles of these effectors in virulence especially in P. capsici. In this study, we identified a cell death-inducing CRN effector PcCRN4 using agroinfiltration approach. Transient expression of PcCRN4 gene induced cell death in N. benthamiana, N. tabacum and Solanum lycopersicum. Overexpression of the gene in N. benthamiana enhanced susceptibility to P. capsici. Subcellular localization results showed that PcCRN4 localized to the plant nucleus, and the localization was required for both of its cell death-inducing activity and virulent function. Silencing PcCRN4 gene in P. capsici significantly reduced pathogen virulence. The expression of the pathogenesis-related gene PR1b in N. benthamiana was significantly induced when plants were inoculated with PcCRN4-silenced P. capsici transformant compared to the wilt-type. Callose deposits were also abundant at sites inoculated with PcCRN4-silenced transformant, indicating that silencing of PcCRN4 in P. capsici reduced the ability of the pathogen to suppress plant defenses. Transcriptions of cell death-related genes were affected when PcCRN4-silenced line were inoculated on Arabidopsis thaliana, suggesting that PcCRN4 may induce cell death by manipulating cell death-related genes. Overall, our results demonstrate that PcCRN4 is a virulence essential effector and it needs target to the plant nucleus to suppress plant immune responses.

Natural Antioxidants in Foods and Medicinal Plants: Extraction, Assessment and Resources

PubMed Central

Xu, Dong-Ping; Li, Ya; Meng, Xiao; Zhou, Tong; Zhou, Yue; Zheng, Jie; Zhang, Jiao-Jiao; Li, Hua-Bin

2017-01-01

Natural antioxidants are widely distributed in food and medicinal plants. These natural antioxidants, especially polyphenols and carotenoids, exhibit a wide range of biological effects, including anti-inflammatory, anti-aging, anti-atherosclerosis and anticancer. The effective extraction and proper assessment of antioxidants from food and medicinal plants are crucial to explore the potential antioxidant sources and promote the application in functional foods, pharmaceuticals and food additives. The present paper provides comprehensive information on the green extraction technologies of natural antioxidants, assessment of antioxidant activity at chemical and cellular based levels and their main resources from food and medicinal plants. PMID:28067795

Natural Antioxidants in Foods and Medicinal Plants: Extraction, Assessment and Resources.

PubMed

Xu, Dong-Ping; Li, Ya; Meng, Xiao; Zhou, Tong; Zhou, Yue; Zheng, Jie; Zhang, Jiao-Jiao; Li, Hua-Bin

2017-01-05

Natural antioxidants are widely distributed in food and medicinal plants. These natural antioxidants, especially polyphenols and carotenoids, exhibit a wide range of biological effects, including anti-inflammatory, anti-aging, anti-atherosclerosis and anticancer. The effective extraction and proper assessment of antioxidants from food and medicinal plants are crucial to explore the potential antioxidant sources and promote the application in functional foods, pharmaceuticals and food additives. The present paper provides comprehensive information on the green extraction technologies of natural antioxidants, assessment of antioxidant activity at chemical and cellular based levels and their main resources from food and medicinal plants.

Herbivorous insects and plant pathogen work together to suppress an invasive tree performance

USDA-ARS?s Scientific Manuscript database

Exotic, invasive plants continue to plague managed as well as natural ecosystems. Land managers rely heavily on cultural, mechanical, or herbicidal tools (singly or in combination) to control weedy invasive plants. While these tools are effective, managers and consumers are increasingly opting for m...

Fuel prices, emission standards, and generation costs for coal vs natural gas power plants.

PubMed

Pratson, Lincoln F; Haerer, Drew; Patiño-Echeverri, Dalia

2013-05-07

Low natural gas prices and stricter, federal emission regulations are promoting a shift away from coal power plants and toward natural gas plants as the lowest-cost means of generating electricity in the United States. By estimating the cost of electricity generation (COE) for 304 coal and 358 natural gas plants, we show that the economic viability of 9% of current coal capacity is challenged by low natural gas prices, while another 56% would be challenged by the stricter emission regulations. Under the current regulations, coal plants would again become the dominant least-cost generation option should the ratio of average natural gas to coal prices (NG2CP) rise to 1.8 (it was 1.42 in February 2012). If the more stringent emission standards are enforced, however, natural gas plants would remain cost competitive with a majority of coal plants for NG2CPs up to 4.3.

Suppression of Poxvirus Replication by Resveratrol.

PubMed

Cao, Shuai; Realegeno, Susan; Pant, Anil; Satheshkumar, Panayampalli S; Yang, Zhilong

2017-01-01

Poxviruses continue to cause serious diseases even after eradication of the historically deadly infectious human disease, smallpox. Poxviruses are currently being developed as vaccine vectors and cancer therapeutic agents. Resveratrol is a natural polyphenol stilbenoid found in plants that has been shown to inhibit or enhance replication of a number of viruses, but the effect of resveratrol on poxvirus replication is unknown. In the present study, we found that resveratrol dramatically suppressed the replication of vaccinia virus (VACV), the prototypic member of poxviruses, in various cell types. Resveratrol also significantly reduced the replication of monkeypox virus, a zoonotic virus that is endemic in Western and Central Africa and causes human mortality. The inhibitory effect of resveratrol on poxviruses is independent of VACV N1 protein, a potential resveratrol binding target. Further experiments demonstrated that resveratrol had little effect on VACV early gene expression, while it suppressed VACV DNA synthesis, and subsequently post-replicative gene expression.

Do Refuge Plants Favour Natural Pest Control in Maize Crops?

PubMed Central

Quispe, Reinaldo; Mazón, Marina; Rodríguez-Berrío, Alexander

2017-01-01

The use of non-crop plants to provide the resources that herbivorous crop pests’ natural enemies need is being increasingly incorporated into integrated pest management programs. We evaluated insect functional groups found on three refuges consisting of five different plant species each, planted next to a maize crop in Lima, Peru, to investigate which refuge favoured natural control of herbivores considered as pests of maize in Peru, and which refuge plant traits were more attractive to those desirable enemies. Insects occurring in all the plants, including the maize crop itself, were sampled weekly during the crop growing cycle, from February to June 2011. All individuals collected were identified and classified into three functional groups: herbivores, parasitoids, and predators. Refuges were compared based on their effectiveness in enhancing the populations of predator and parasitoid insects of the crop enemies. Refuges A and B were the most effective, showing the highest richness and abundance of both predators and parasitoids, including several insect species that are reported to attack the main insect pests of maize (Spodoptera frugiperda and Rhopalosiphum maidis), as well as other species that serve as alternative hosts of these natural enemies. PMID:28718835

Radon emissions from natural gas power plants at The Pennsylvania State University.

PubMed

Stidworthy, Alison G; Davis, Kenneth J; Leavey, Jeff

2016-11-01

Burning natural gas in power plants may emit radon ( 222 Rn) into the atmosphere. On the University Park campus of The Pennsylvania State University, atmospheric radon enhancements were measured and modeled in the vicinity of their two power plants. The three-part study first involved measuring ambient outdoor radon concentrations from August 2014 through January 2015 at four sites upwind and downwind of the power plants at distances ranging from 80 m to 310 m. For each plant, one site served as a background site, while three other sites measured radon concentration enhancements downwind. Second, the radon content of natural gas flowing into the power plant was measured, and third, a plume dispersion model was used to predict the radon concentrations downwind of the power plants. These predictions are compared to the measured downwind enhancements in radon to determine whether the observed radon concentration enhancements could be attributed to the power plants' emissions. Atmospheric radon concentrations were consistently low as compared to the EPA action level of 148 Bq m -3 , averaging 34.5 ± 2.7 Bq m -3 around the East Campus Steam Plant (ECSP) and 31.6 ± 2.7 Bq m -3 around the West Campus Steam Plant (WCSP). Significant concentrations of radon, ranging from 516 to 1,240 Bq m -3 , were detected in the natural gas. The measured enhancements downwind of the ECSP averaged 6.2 Bq m -3 compared to modeled enhancements of 0.08 Bq m -3 . Measured enhancements around the WCSP averaged -0.2 Bq m -3 compared to the modeled enhancements of 0.05 Bq m -3 , which were not significant compared to observational error. The comparison of the measured to modeled downwind radon enhancements shows no correlation over time. The measurements of radon levels in the vicinity of the power plants appear to be unaffected by the emissions from the power plants. Radon measurements at sites surrounding power plants that utilize natural gas did not indicate that the radon concentrations

Climate change may threaten habitat suitability of threatened plant species within Chinese nature reserves

PubMed Central

Wan, Jizhong

2016-01-01

Climate change has the potential to alter the distributions of threatened plant species, and may therefore diminish the capacity of nature reserves to protect threatened plant species. Chinese nature reserves contain a rich diversity of plant species that are at risk of becoming more threatened by climate change. Hence, it is urgent to identify the extent to which future climate change may compromise the suitability of threatened plant species habitats within Chinese nature reserves. Here, we modelled the climate suitability of 82 threatened plant species within 168 nature reserves across climate change scenarios. We used Maxent modelling based on species occurrence localities and evaluated climate change impacts using the magnitude of change in climate suitability and the degree of overlap between current and future climatically suitable habitats. There was a significant relationship between overlap with current and future climate suitability of all threatened plant species habitats and the magnitude of changes in climate suitability. Our projections estimate that the climate suitability of more than 60 threatened plant species will decrease and that climate change threatens the habitat suitability of plant species in more than 130 nature reserves under the low, medium, and high greenhouse gas concentration scenarios by both 2050s and 2080s. Furthermore, future climate change may substantially threaten tree plant species through changes in annual mean temperature. These results indicate that climate change may threaten plant species that occur within Chinese nature reserves. Therefore, we suggest that climate change projections should be integrated into the conservation and management of threatened plant species within nature reserves. PMID:27326373

Can plant-natural enemy communication withstand disruption by biotic and abiotic factors?

PubMed

Clavijo McCormick, Andrea

2016-12-01

The attraction of natural enemies towards herbivore-induced plant volatiles is a well-documented phenomenon. However, the majority of published studies are carried under optimal water and nutrient regimes and with just one herbivore. But what happens when additional levels of ecological complexity are added? Does the presence of a second herbivore, microorganisms, and abiotic stress interfere with plant-natural enemy communication? or is communication stable enough to withstand disruption by additional biotic and abiotic factors?Investigating the effects of these additional levels of ecological complexity is key to understanding the stability of tritrophic interactions in natural ecosystems and may aid to forecast the impact of environmental disturbances on these, especially in climate change scenarios, which are often associated with modifications in plant and arthropod species distribution and increased levels of abiotic stress.This review explores the literature on natural enemy attraction to herbivore-induced volatiles when, besides herbivory, plants are challenged by additional biotic and abiotic factors.The aim of this review was to establish the impact of different biotic and abiotic factors on plant-natural enemy communication and to highlight critical aspects to guide future research efforts.

Screening and Characterization of Potentially Suppressive Soils against Gaeumannomyces graminis under Extensive Wheat Cropping by Chilean Indigenous Communities.

PubMed

Durán, Paola; Jorquera, Milko; Viscardi, Sharon; Carrion, Victor J; Mora, María de la Luz; Pozo, María J

2017-01-01

Wheat production around the world is severely compromised by the occurrence of "take-all" disease, which is caused by the soil-borne pathogen Gaeumannomyces graminis var. tritici (Ggt). In this context, suppressive soils are those environments in which plants comparatively suffer less soil-borne pathogen diseases than expected, owing to native soil microorganism activities. In southern Chile, where 85% of the national cereal production takes place, several studies have suggested the existence of suppressive soils under extensive wheat cropping. Thus, this study aimed to screen Ggt-suppressive soil occurrence in 16 locations managed by indigenous "Mapuche" communities, using extensive wheat cropping for more than 10 years. Ggt growth inhibition in vitro screenings allowed the identification of nine putative suppressive soils. Six of these soils, including Andisols and Ultisols, were confirmed to be suppressive, since they reduced take-all disease in wheat plants growing under greenhouse conditions. Suppressiveness was lost upon soil sterilization, and recovered by adding 1% of the natural soil, hence confirming that suppressiveness was closely associated to the soil microbiome community composition. Our results demonstrate that long-term extensive wheat cropping, established by small Mapuche communities, can generate suppressive soils that can be used as effective microorganism sources for take-all disease biocontrol. Accordingly, suppressive soil identification and characterization are key steps for the development of environmentally-friendly and efficient biotechnological applications for soil-borne disease control.

Compressed Natural Gas Technology for Alternative Fuel Power Plants

NASA Astrophysics Data System (ADS)

Pujotomo, Isworo

2018-02-01

Gas has great potential to be converted into electrical energy. Indonesia has natural gas reserves up to 50 years in the future, but the optimization of the gas to be converted into electricity is low and unable to compete with coal. Gas is converted into electricity has low electrical efficiency (25%), and the raw materials are more expensive than coal. Steam from a lot of wasted gas turbine, thus the need for utilizing exhaust gas results from gas turbine units. Combined cycle technology (Gas and Steam Power Plant) be a solution to improve the efficiency of electricity. Among other Thermal Units, Steam Power Plant (Combined Cycle Power Plant) has a high electrical efficiency (45%). Weakness of the current Gas and Steam Power Plant peak burden still using fuel oil. Compressed Natural Gas (CNG) Technology may be used to accommodate the gas with little land use. CNG gas stored in the circumstances of great pressure up to 250 bar, in contrast to gas directly converted into electricity in a power plant only 27 bar pressure. Stored in CNG gas used as a fuel to replace load bearing peak. Lawyer System on CNG conversion as well as the power plant is generally only used compressed gas with greater pressure and a bit of land.

Methods of natural gas liquefaction and natural gas liquefaction plants utilizing multiple and varying gas streams

DOEpatents

Wilding, Bruce M; Turner, Terry D

2014-12-02

A method of natural gas liquefaction may include cooling a gaseous NG process stream to form a liquid NG process stream. The method may further include directing the first tail gas stream out of a plant at a first pressure and directing a second tail gas stream out of the plant at a second pressure. An additional method of natural gas liquefaction may include separating CO.sub.2 from a liquid NG process stream and processing the CO.sub.2 to provide a CO.sub.2 product stream. Another method of natural gas liquefaction may include combining a marginal gaseous NG process stream with a secondary substantially pure NG stream to provide an improved gaseous NG process stream. Additionally, a NG liquefaction plant may include a first tail gas outlet, and at least a second tail gas outlet, the at least a second tail gas outlet separate from the first tail gas outlet.

Cyanide production by Pseudomonas fluorescens helps suppress black root rot of tobacco under gnotobiotic conditions

PubMed Central

Voisard, Christophe; Keel, Christoph; Haas, Dieter; Dèfago, Geneviève

1989-01-01

Pseudomonas fluorescens CHA0 suppresses black root rot of tobacco, a disease caused by the fungus Thielaviopsis basicola. Strain CHA0 excretes several metabolites with antifungal properties. The importance of one such metabolite, hydrogen cyanide, was tested in a gnotobiotic system containing an artificial, iron-rich soil. A cyanidenegative (hcn) mutant, CHA5, constructed by a gene replacement technique, protected the tobacco plant less effectively than did the wild-type CHA0. Complementation of strain CHA5 by the cloned wild-type hcn+ genes restored the strain's ability to suppress disease. An artificial transposon carrying the hcn+ genes of strain CHA0 (Tnhcn) was constructed and inserted into the genome of another P.fluorescens strain, P3, which naturally does not produce cyanide and gives poor plant protection. The P3::Tnhcn derivative synthesized cyanide and exhibited an improved ability to suppress disease. All bacterial strains colonized the roots similarly and did not influence significantly the survival of T.basicola in soil. We conclude that bacterial cyanide is an important but not the only factor involved in suppression of black root rot. Images PMID:16453871

On high suppression of NO x and CO emissions in gas-turbine plants with combined gas-and-steam cycles

NASA Astrophysics Data System (ADS)

Ivanov, A. A.; Ermakov, A. N.; Shlyakhov, R. A.

2010-12-01

In this work are given results of analyzing processes of production of nitrogen oxides (NO x ) and afterburning of CO when firing natural gas at combined-cycle gas-turbine plants. It is shown that for suppressing emissions of the said microcomponents it is necessary to lower temperature in hot local zones of the flame in which NOx is formed, and, in so doing, to avoid chilling of cold flame zones that prevents afterburning of CO. The required lowering of the combustion temperature can be provided by combustion of mixtures of methane with steam, with high mixing uniformity that ensures the same and optimum fraction of the steam "ballast" in each microvolume of the flame. In addition to chilling, the steam ballast makes it possible to maintain a fairly high concentration of hydroxil radicals in the flame zone as well, and this provides high burning out of fuel and reduction in carbon monoxide emissions (active steam ballast). Due to this fact the fraction of steam when firing its mixtures with methane in a gas-turbine plant can be increased up to the weight ratio 4: 1. In this case, the concentrations of NO x and CO in emissions can be reduced to ultra-low values (less than 3 ppm).

Factors driving natural regeneration beneath a planted urban forest

Treesearch

Danica A. Doroski; Alexander J. Felson; Mark A. Bradford; Mark P. Ashton; Emily E. Oldfield; Richard A. Hallett; Sara E. Kuebbing

2018-01-01

Cities around the world are investing in urban forest plantings as a form of green infrastructure. The aim is that these plantations will develop into naturally-regenerating native forest stands. However, woody plant recruitment is often cited as the most limiting factor to creating self-sustaining urban forests. As such, there is interest in site treatments that...

Comparative Metatranscriptomics of Wheat Rhizosphere Microbiomes in Disease Suppressive and Non-suppressive Soils for Rhizoctonia solani AG8

PubMed Central

Hayden, Helen L.; Savin, Keith W.; Wadeson, Jenny; Gupta, Vadakattu V. S. R.; Mele, Pauline M.

2018-01-01

The soilborne fungus Rhizoctonia solani anastomosis group (AG) 8 is a major pathogen of grain crops resulting in substantial production losses. In the absence of resistant cultivars of wheat or barley, a sustainable and enduring method for disease control may lie in the enhancement of biological disease suppression. Evidence of effective biological control of R. solani AG8 through disease suppression has been well documented at our study site in Avon, South Australia. A comparative metatranscriptomic approach was applied to assess the taxonomic and functional characteristics of the rhizosphere microbiome of wheat plants grown in adjacent fields which are suppressive and non-suppressive to the plant pathogen R. solani AG8. Analysis of 12 rhizosphere metatranscriptomes (six per field) was undertaken using two bioinformatic approaches involving unassembled and assembled reads. Differential expression analysis showed the dominant taxa in the rhizosphere based on mRNA annotation were Arthrobacter spp. and Pseudomonas spp. for non-suppressive samples and Stenotrophomonas spp. and Buttiauxella spp. for the suppressive samples. The assembled metatranscriptome analysis identified more differentially expressed genes than the unassembled analysis in the comparison of suppressive and non-suppressive samples. Suppressive samples showed greater expression of a polyketide cyclase, a terpenoid biosynthesis backbone gene (dxs) and many cold shock proteins (csp). Non-suppressive samples were characterised by greater expression of antibiotic genes such as non-heme chloroperoxidase (cpo) which is involved in pyrrolnitrin synthesis, and phenazine biosynthesis family protein F (phzF) and its transcriptional activator protein (phzR). A large number of genes involved in detoxifying reactive oxygen species (ROS) and superoxide radicals (sod, cat, ahp, bcp, gpx1, trx) were also expressed in the non-suppressive rhizosphere samples most likely in response to the infection of wheat roots by R

Transgenerational Effects Alter Plant Defense and Resistance in Nature

PubMed Central

Colicchio, Jack

2017-01-01

Trichomes, or leaf hairs, are epidermal extensions that take a variety of forms and perform many functions in plants, including herbivore defense. In this study, I document genetically determined variation, within-generation plasticity, and a direct role of trichomes in herbivore defense for Mimulus guttatus. After establishing the relationship between trichomes and herbivory, I test for transgenerational effects of wounding on trichome density and herbivore resistance. Patterns of inter-annual variation in herbivore density and the high cost of plant defense makes plant-herbivore interactions a system in which transgenerational phenotypic plasticity (TPP) is apt to evolve. Here, I demonstrate that parental damage alters offspring trichome density and herbivore resistance in nature. Moreover, this response varies between populations. This is among the first studies to demonstrate that TPP contributes to variation in nature, and also suggests that selection can modify TPP in response to local conditions. PMID:28102915

Patients' recovery experiences of indoor plants and viewsof nature in a rehabilitation center.

PubMed

Raanaas, Ruth Kjærsti; Patil, Grete; Alve, Grete

2015-01-01

There is an increasing interest in the possible healing factors connected to the presence of nature elements in health institutions. The aim of the present study is to get a deeper understanding of how residents in a residential rehabilitation center experience the views through windows and the indoor plants, and whether and how the view and the plants can impact their recovery process. In-depth individual and group interviews were conducted among 16 residents at a rehabilitation center in Norway. The participants said that the indoor plants and the view of nature were pleasant to look at and elicited feelings of relaxation and positive emotions which contributed to opportunities for reflection and contemplation. They expressed a feeling of connectedness to nature: a feeling of wholeness and spirituality elicited by the nature elements. They also expressed that the presence of nature elements contributed to a sense of being taken care of. The nature elements, such as a view of nature or indoor plants, seem to enhance opportunities for reflection, feelings of meaningfulness and sense of being taken care of which may strengthen their feeling of well-being and make them more resilient to the stressors in life.

Screening and Characterization of Potentially Suppressive Soils against Gaeumannomyces graminis under Extensive Wheat Cropping by Chilean Indigenous Communities

PubMed Central

Durán, Paola; Jorquera, Milko; Viscardi, Sharon; Carrion, Victor J.; Mora, María de la Luz; Pozo, María J.

2017-01-01

Wheat production around the world is severely compromised by the occurrence of “take-all” disease, which is caused by the soil-borne pathogen Gaeumannomyces graminis var. tritici (Ggt). In this context, suppressive soils are those environments in which plants comparatively suffer less soil-borne pathogen diseases than expected, owing to native soil microorganism activities. In southern Chile, where 85% of the national cereal production takes place, several studies have suggested the existence of suppressive soils under extensive wheat cropping. Thus, this study aimed to screen Ggt-suppressive soil occurrence in 16 locations managed by indigenous “Mapuche” communities, using extensive wheat cropping for more than 10 years. Ggt growth inhibition in vitro screenings allowed the identification of nine putative suppressive soils. Six of these soils, including Andisols and Ultisols, were confirmed to be suppressive, since they reduced take-all disease in wheat plants growing under greenhouse conditions. Suppressiveness was lost upon soil sterilization, and recovered by adding 1% of the natural soil, hence confirming that suppressiveness was closely associated to the soil microbiome community composition. Our results demonstrate that long-term extensive wheat cropping, established by small Mapuche communities, can generate suppressive soils that can be used as effective microorganism sources for take-all disease biocontrol. Accordingly, suppressive soil identification and characterization are key steps for the development of environmentally-friendly and efficient biotechnological applications for soil-borne disease control. PMID:28861064

Induced plant-defenses suppress herbivore reproduction but also constrain predation of their offspring.

PubMed

Ataide, Livia M S; Pappas, Maria L; Schimmel, Bernardus C J; Lopez-Orenes, Antonio; Alba, Juan M; Duarte, Marcus V A; Pallini, Angelo; Schuurink, Robert C; Kant, Merijn R

2016-11-01

Inducible anti-herbivore defenses in plants are predominantly regulated by jasmonic acid (JA). On tomato plants, most genotypes of the herbivorous generalist spider mite Tetranychus urticae induce JA defenses and perform poorly on it, whereas the Solanaceae specialist Tetranychus evansi, who suppresses JA defenses, performs well on it. We asked to which extent these spider mites and the predatory mite Phytoseiulus longipes preying on these spider mites eggs are affected by induced JA-defenses. By artificially inducing the JA-response of the tomato JA-biosynthesis mutant def-1 using exogenous JA and isoleucine (Ile), we first established the relationship between endogenous JA-Ile-levels and the reproductive performance of spider mites. For both mite species we observed that they produced more eggs when levels of JA-Ile were low. Subsequently, we allowed predatory mites to prey on spider mite-eggs derived from wild-type tomato plants, def-1 and JA-Ile-treated def-1 and observed that they preferred, and consumed more, eggs produced on tomato plants with weak JA defenses. However, predatory mite oviposition was similar across treatments. Our results show that induced JA-responses negatively affect spider mite performance, but positively affect the survival of their offspring by constraining egg-predation. Copyright © 2016 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Natural plant chemicals: source of industrial and medicinal materials

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

Balandrin, M.F.; Klocke, J.A.; Wurtele, E.S.

1985-01-01

Many higher plants produce economically important organic compounds such as oils, resins, tannins, natural rubber, gums, waxes, dyes, flavors and fragrances, pharmaceuticals, and pesticides. However, most species of higher plants have never been described, much less surveyed for chemical or biologically active constituents, and new sources of commercially valuable materials remain to be discovered. Advances in biotechnology, particularly methods for culturing plants cells and tissues, should provide new means for the commercial processing of even rare plants and the chemicals they produce. These new technologies will extend and enhance the usefulness of plants as renewable resources of valuable chemicals. Inmore » the future, biologically active plant-derived chemicals can be expected to play an increasingly significant role in the commercial development of new products for regulating plant growth and for insect and weed control. 65 references.« less

Plant growth-promoting rhizobacteria strain Bacillus amyloliquefaciens NJN-6-enriched bio-organic fertilizer suppressed Fusarium wilt and promoted the growth of banana plants.

PubMed

Yuan, Jun; Ruan, Yunze; Wang, Beibei; Zhang, Jian; Waseem, Raza; Huang, Qiwei; Shen, Qirong

2013-04-24

Bacillus amyloliquefaciens strain NJN-6 is an important plant growth-promoting rhizobacteria (PGPR) which can produce secondary metabolites antagonistic to several soil-borne pathogens. In this study, the ability of a bio-organic fertilizer (BIO) containing NJN-6 strain to promote the growth and suppress Fusarium wilt of banana plants was evaluated in a pot experiment. The results showed that the application of BIO significantly decreased the incidence of Fusarium wilt and promoted the growth of banana plants compared to that for the organic fertilizer (OF). To determine the beneficial mechanism of the strain, the colonization of NJN-6 strain on banana roots was evaluated using scanning electron microscopy (SEM). The plant growth-promoting hormones indole-3-acetic acid (IAA) and gibberellin A3 (GA3), along with antifungal lipopeptides iturin A, were detected when the NJN-6 strain was incubated in both Landy medium with additional l-tryptophan and in root exudates of banana plants. In addition, some antifungal volatile organic compounds and iturin A were also detected in BIO. In summary, strain NJN-6 could colonize the roots of banana plants after the application of BIO and produced active compounds which were beneficial for the growth of banana plants.

Effect of Sunn Hemp (Crotalaria juncea L.) Cutting Date and Planting Density on Weed Suppression in Georgia, USA

USDA-ARS?s Scientific Manuscript database

A field study was conducted in 2008 and 2009 at the USDA, ARS, Plant Genetic Resources Conservation Unit in Griffin, GA to investigate weed suppression by sunn hemp (Crotalaria juncea L). The objectives were to: 1) evaluate the effects of apical meristem removal (AMR) at three dates [5, 6, and 7 wks...

Climate change will increase the naturalization risk from garden plants in Europe.

PubMed

Dullinger, Iwona; Wessely, Johannes; Bossdorf, Oliver; Dawson, Wayne; Essl, Franz; Gattringer, Andreas; Klonner, Günther; Kreft, Holger; Kuttner, Michael; Moser, Dietmar; Pergl, Jan; Pyšek, Petr; Thuiller, Wilfried; van Kleunen, Mark; Weigelt, Patrick; Winter, Marten; Dullinger, Stefan; Beaumont, Linda

2017-01-01

Plant invasions often follow initial introduction with a considerable delay. The current non-native flora of a region may hence contain species that are not yet naturalized but may become so in the future, especially if climate change lifts limitations on species spread. In Europe, non-native garden plants represent a huge pool of potential future invaders. Here, we evaluate the naturalization risk from this species pool and how it may change under a warmer climate. Europe. We selected all species naturalized anywhere in the world but not yet in Europe from the set of non-native European garden plants. For this subset of 783 species, we used species distribution models to assess their potential European ranges under different scenarios of climate change. Moreover, we defined geographical hotspots of naturalization risk from those species by combining projections of climatic suitability with maps of the area available for ornamental plant cultivation. Under current climate, 165 species would already find suitable conditions in > 5% of Europe. Although climate change substantially increases the potential range of many species, there are also some that are predicted to lose climatically suitable area under a changing climate, particularly species native to boreal and Mediterranean biomes. Overall, hotspots of naturalization risk defined by climatic suitability alone, or by a combination of climatic suitability and appropriate land cover, are projected to increase by up to 102% or 64%, respectively. Our results suggest that the risk of naturalization of European garden plants will increase with warming climate, and thus it is very likely that the risk of negative impacts from invasion by these plants will also grow. It is therefore crucial to increase awareness of the possibility of biological invasions among horticulturalists, particularly in the face of a warming climate.

Climate change will increase the naturalization risk from garden plants in Europe

PubMed Central

Wessely, Johannes; Bossdorf, Oliver; Dawson, Wayne; Essl, Franz; Gattringer, Andreas; Klonner, Günther; Kreft, Holger; Kuttner, Michael; Moser, Dietmar; Pergl, Jan; Pyšek, Petr; Thuiller, Wilfried; van Kleunen, Mark; Weigelt, Patrick; Winter, Marten; Dullinger, Stefan; Beaumont, Linda

2016-01-01

Abstract Aim Plant invasions often follow initial introduction with a considerable delay. The current non‐native flora of a region may hence contain species that are not yet naturalized but may become so in the future, especially if climate change lifts limitations on species spread. In Europe, non‐native garden plants represent a huge pool of potential future invaders. Here, we evaluate the naturalization risk from this species pool and how it may change under a warmer climate. Location Europe. Methods We selected all species naturalized anywhere in the world but not yet in Europe from the set of non‐native European garden plants. For this subset of 783 species, we used species distribution models to assess their potential European ranges under different scenarios of climate change. Moreover, we defined geographical hotspots of naturalization risk from those species by combining projections of climatic suitability with maps of the area available for ornamental plant cultivation. Results Under current climate, 165 species would already find suitable conditions in > 5% of Europe. Although climate change substantially increases the potential range of many species, there are also some that are predicted to lose climatically suitable area under a changing climate, particularly species native to boreal and Mediterranean biomes. Overall, hotspots of naturalization risk defined by climatic suitability alone, or by a combination of climatic suitability and appropriate land cover, are projected to increase by up to 102% or 64%, respectively. Main conclusions Our results suggest that the risk of naturalization of European garden plants will increase with warming climate, and thus it is very likely that the risk of negative impacts from invasion by these plants will also grow. It is therefore crucial to increase awareness of the possibility of biological invasions among horticulturalists, particularly in the face of a warming climate. PMID:28111525

Exploring the Potential for Using Inexpensive Natural Reagents Extracted from Plants to Teach Chemical Analysis

ERIC Educational Resources Information Center

Hartwell, Supaporn Kradtap

2012-01-01

A number of scientific articles report on the use of natural extracts from plants as chemical reagents, where the main objective is to present the scientific applications of those natural plant extracts. The author suggests that natural reagents extracted from plants can be used as alternative low cost tools in teaching chemical analysis,…

Plants and their active compounds: natural molecules to target angiogenesis.

PubMed

Lu, Kai; Bhat, Madhavi; Basu, Sujit

2016-07-01

Angiogenesis, or new blood vessel formation, is an important process in the pathogenesis of several diseases and thus has been targeted for the prevention and treatment for many disorders. However, the anti-angiogenic agents that are currently in use are mainly synthetic compounds and humanized monoclonal antibodies, which are either expensive or toxic, thereby limiting their use in many patients. Therefore, it is necessary to identify less toxic, inexpensive, novel and effective anti-angiogenic molecules. Several studies have indicated that natural plant products can meet these criteria. In this review, we discuss the anti-angiogenic properties of natural compounds isolated from plants and the molecular mechanisms by which these molecules act. Finally, we summarize the advantages of using plant products as anti-angiogenic agents. Compared with currently available anti-angiogenic drugs, plant products may not only have similar therapeutic potential but are also inexpensive, less toxic, and easy to administer. However, novel and effective strategies are necessary to improve their bioavailability for clinical use.

Indirect plant defense against insect herbivores: a review.

PubMed

Aljbory, Zainab; Chen, Ming-Shun

2018-02-01

Plants respond to herbivore attack by launching 2 types of defenses: direct defense and indirect defense. Direct defense includes all plant traits that increase the resistance of host plants to insect herbivores by affecting the physiology and/or behavior of the attackers. Indirect defense includes all traits that by themselves do not have significant direct impact on the attacking herbivores, but can attract natural enemies of the herbivores and thus reduce plant loss. When plants recognize herbivore-associated elicitors, they produce and release a blend of volatiles that can attract predators, parasites, and other natural enemies. Known herbivore-associated elicitors include fatty acid-amino acid conjugates, sulfur-containing fatty acids, fragments of cell walls, peptides, esters, and enzymes. Identified plant volatiles include terpenes, nitrogenous compounds, and indoles. In addition, constitive traits including extrafloral nectars, food bodies, and domatia can be further induced to higher levels and attract natural enemies as well as provide food and shelter to carnivores. A better understanding of indirect plant defense at global and componential levels via advanced high throughput technologies may lead to utilization of indirect defense in suppression of herbivore damage to plants. © 2016 Institute of Zoology, Chinese Academy of Sciences.

Effect of land use and soil organic matter quality on the structure and function of microbial communities in pastoral soils: Implications for disease suppression

PubMed Central

O’Callaghan, Maureen; Condron, Leo M.; Kowalchuk, George A.; Van Nostrand, Joy D.; Zhou, Jizhong; Wakelin, Steven A.

2018-01-01

Cropping soils vary in extent of natural suppression of soil-borne plant diseases. However, it is unknown whether similar variation occurs across pastoral agricultural systems. We examined soil microbial community properties known to be associated with disease suppression across 50 pastoral fields varying in management intensity. The composition and abundance of the disease-suppressive community were assessed from both taxonomic and functional perspectives. Pseudomonas bacteria were selected as a general taxonomic indicator of disease suppressive potential, while genes associated with the biosynthesis of a suite of secondary metabolites provided functional markers (GeoChip 5.0 microarray analysis). The composition of both the Pseudomonas communities and disease suppressive functional genes were responsive to land use. Underlying soil properties explained 37% of the variation in Pseudomonas community structure and up to 61% of the variation in the abundance of disease suppressive functional genes. Notably, measures of soil organic matter quality, C:P ratio, and aromaticity of the dissolved organic matter content (carbon recalcitrance), influenced both the taxonomic and functional disease suppressive potential of the pasture soils. Our results suggest that key components of the soil microbial community may be managed on-farm to enhance disease suppression and plant productivity. PMID:29734390

Effect of land use and soil organic matter quality on the structure and function of microbial communities in pastoral soils: Implications for disease suppression.

PubMed

Dignam, Bryony E A; O'Callaghan, Maureen; Condron, Leo M; Kowalchuk, George A; Van Nostrand, Joy D; Zhou, Jizhong; Wakelin, Steven A

2018-01-01

Cropping soils vary in extent of natural suppression of soil-borne plant diseases. However, it is unknown whether similar variation occurs across pastoral agricultural systems. We examined soil microbial community properties known to be associated with disease suppression across 50 pastoral fields varying in management intensity. The composition and abundance of the disease-suppressive community were assessed from both taxonomic and functional perspectives. Pseudomonas bacteria were selected as a general taxonomic indicator of disease suppressive potential, while genes associated with the biosynthesis of a suite of secondary metabolites provided functional markers (GeoChip 5.0 microarray analysis). The composition of both the Pseudomonas communities and disease suppressive functional genes were responsive to land use. Underlying soil properties explained 37% of the variation in Pseudomonas community structure and up to 61% of the variation in the abundance of disease suppressive functional genes. Notably, measures of soil organic matter quality, C:P ratio, and aromaticity of the dissolved organic matter content (carbon recalcitrance), influenced both the taxonomic and functional disease suppressive potential of the pasture soils. Our results suggest that key components of the soil microbial community may be managed on-farm to enhance disease suppression and plant productivity.

[Plants as a source of natural harmful substances].

PubMed

Czerwiecki, Ludwik

2005-01-01

In this review the several data concerning phytotoxins as natural harmful substances of plants and phycotoxins--toxicants of algae were described. For example plants are source of pyrrolizidine alkaloids, glycoalkaloids, glucosinolates as well as glycosides, saponine and psolarens. Possible adverse effects of phytoestrogens as endocrine disruptors versus beneficial influence these substances on human organism were mentioned. About lectins as possible factors of some diseases was reported, as well as some proteins as allergens of soy and peanuts was mentioned. Accumulated by shellfish and fish the most important phycotoxins such as saxitoxin, okadaic acid, brevetoxins and ciguatoxins were described. Phycotoxins produced several poisoning symptoms. Microcystins and nodularin--cyanobacterial phycotoxins of freshwater, was mentioned. In conclusion, the need of limitation of permissible levels of some plant toxicants, development of analytical methods as well as knowledge of influence of some technological processes on toxic plant substances was highlighted. The importance of balanced diet as a tool of defense against plant toxicants was concluded.

Plant biochemistry: a naturally decaffeinated arabica coffee.

PubMed

Silvarolla, Maria B; Mazzafera, Paulo; Fazuoli, Luiz C

2004-06-24

The adverse side effects of caffeine have increased the market for decaffeinated coffee to about 10% of coffee consumption worldwide (http://www.ncausa.org), despite the loss of key flavour compounds in the industrial decaffeinating process. We have discovered a naturally decaffeinated Coffea arabica plant from Ethiopia, a species normally recognized for the high quality of its beans. It should be possible to transfer this trait to commercial varieties of arabica coffee plants by intraspecific hybridization--a process likely to be simpler than an interspecific hybridization strategy, which could require more than 30 years of breeding to fix the decaffeinated trait and would probably result in an inferior cup of coffee.

FT Raman microscopy of untreated natural plant fibres

NASA Astrophysics Data System (ADS)

Edwards, H. G. M.; Farwell, D. W.; Webster, D.

1997-11-01

The application of FT-Raman microscopy to the non-destructive analysis of natural plant fibres is demonstrated with samples of flax, jute, ramie, cotton, kapok, sisal and coconut fibre. Vibrational assignments are proposed and characteristic features of each material are presented. Samples were not pre-treated chemically before analysis and were used directly from their respective storage collection; the adaptation of the Raman microscopic technique to the identification of specimens of natural fibres in archaeological burial sites is explored for its forensic potential.

Using Plants to Explore the Nature & Structural Complexity of Life

ERIC Educational Resources Information Center

Howard, Ava R.

2014-01-01

Use of real specimens brings the study of biology to life. This activity brings easily acquired plant specimens into the classroom to tackle common alternative conceptions regarding life, size, complexity, the nature of science, and plants as multicellular organisms. The activity occurs after a discussion of the characteristics of life and engages…

Assessing the Greenhouse Gas Emissions from Natural Gas Fired Power Plants

NASA Astrophysics Data System (ADS)

Hajny, K. D.; Shepson, P. B.; Rudek, J.; Stirm, B. H.; Kaeser, R.; Stuff, A. A.

2017-12-01

Natural gas is often discussed as a "bridge fuel" to transition to renewable energy as it only produces 51% the amount of CO2 per unit energy as coal. This, coupled with rapid increases in production fueled by technological advances, has led to a near tripling of natural gas used for electricity generation since 2005. One concern with this idea of a "bridge fuel" is that methane, the primary component of natural gas, is itself a potent greenhouse gas with 28 and 84 times the global warming potential of CO2 based on mass over a 100 and 20 year period, respectively. Studies have estimated that leaks from the point of extraction to end use of 3.2% would offset the climate benefits of natural gas. Previous work from our group saw that 3 combined cycle power plants emitted unburned CH4 from the stacks and leaked additional CH4 from equipment on site, but total loss rates were still less than 2.2%. Using Purdue's Airborne Laboratory for Atmospheric Research (ALAR) we completed additional aircraft based mass balance experiments combined with passes directly over power plant stacks to expand on the previous study. In this work, we have measured at 12 additional natural gas fired power plants including a mix of operation types (baseload, peaking, intermediate) and firing methods (combined cycle, simple thermal, combustion turbine). We have also returned to the 3 plants previously sampled to reinvestigate emissions for each of those, to assess reproducibility of the results. Here we report the comparison of reported continuous emissions monitoring systems (CEMS) data for CO2 to our emission rates calculated from mass balance experiments, as well as a comparison of calculated CH4 emission rates to estimated emission rates based on the EPA emission factor of 1 g CH4/mmbtu natural gas and CEMS reported heat input. We will also discuss emissions from a coal-fired plant which has been sampled by the group in the past and has since converted to natural gas. Lastly, we discuss the

What Has Natural Variation Taught Us about Plant Development, Physiology, and Adaptation?

PubMed Central

Alonso-Blanco, Carlos; Aarts, Mark G.M.; Bentsink, Leonie; Keurentjes, Joost J.B.; Reymond, Matthieu; Vreugdenhil, Dick; Koornneef, Maarten

2009-01-01

Nearly 100 genes and functional polymorphisms underlying natural variation in plant development and physiology have been identified. In crop plants, these include genes involved in domestication traits, such as those related to plant architecture, fruit and seed structure and morphology, as well as yield and quality traits improved by subsequent crop breeding. In wild plants, comparable traits have been dissected mainly in Arabidopsis thaliana. In this review, we discuss the major contributions of the analysis of natural variation to our understanding of plant development and physiology, focusing in particular on the timing of germination and flowering, plant growth and morphology, primary metabolism, and mineral accumulation. Overall, functional polymorphisms appear in all types of genes and gene regions, and they may have multiple mutational causes. However, understanding this diversity in relation to adaptation and environmental variation is a challenge for which tools are now available. PMID:19574434

Review on research of suppression male fertility and male contraceptive drug development by natural products.

PubMed

Bajaj, Vijay Kumar; Gupta, Radhey S

2013-08-01

Male contraceptive development in the present scenario is most viable aspect of research due to uncontrolled population growth in the world. In this respect investigators are busy to find out a safe male contraceptive drug. Researchers have started their finding for a suitable drug from natural sources because these are safe and easily acceptable for common man, most of natural sources are plants and their products. In this review 137 plants and their effects on reproduction and reproductive physiology are summarized. Some of them have intense effect on male reproductive system and do not produce any side effects. Reproductive toxicological studies are also important aspects of these kinds of researches, so it is important that drugs are safe and widely acceptable. An ideal male contraceptive can influence semen, testes, hormone level, accessory reproductive organs and general physiology of animals and produced some alterations. Many plants in this review are showing antifertility as well as antispermatogenic effects, so these may be used for further study for contraceptives development but it is important to find out the mechanism of reaction and further laboratory and clinical research on some plants are needed for final male contraceptive drug development. In conclusion this review will help for finding suitable plant products for male contraceptive clinical and laboratory studies.

Evidence on Possible Mycoplasma Etiology of Aster Yellows Disease I. Suppression of Symptom Development in Plants by Antibiotics

PubMed Central

Davis, R. E.; Whitcomb, R. F.

1970-01-01

Antibiotics suppressed development of aster yellows (AY) disease symptoms in plants of china aster [Callistephus chinensis (L.) Nees.] and annual chrysanthemum (Chrysanthemum carinatum, Schousb.). When inoculated chrysanthemum plants were treated by any of several techniques with tetracycline antibiotics or chloramphenicol, symptoms failed to appear during treatment but appeared 1 to 4 weeks after treatments were terminated. Under continuous administration of chlortetracycline, aster plants with AY symptoms developed symptomless axillary growth, including flowers. Streptomycin, oleandomycin, kanamycin, tylosin, carbomycin, polymyxin, bacitracin, neomycin, sulfanilamide, penicillin, vancomycin, or cycloserine had no discernible effect on development of AY symptoms. Treatment of plants with tetracycline antibiotics before exposure to inoculative (pathogen-transmitting) vectors delayed the appearance of symptoms or prevented AY infection. Remission of AY symptoms in inoculated plants treated with chlortetracycline was correlated with an inhibition of multiplication of AY agent, as measured by bioassay of extracts. The data give additional support to the hypothesis that aster yellows disease is caused by a mycoplasma-like microorganism. Images PMID:16557820

Caterpillar-induced plant volatiles attract conspecific adults in nature

PubMed Central

El-Sayed, Ashraf M.; Knight, Alan L.; Byers, John A.; Judd, Gary J. R.; Suckling, David M.

2016-01-01

Plants release volatiles in response to caterpillar feeding that attract natural enemies of the herbivores, a tri-trophic interaction which has been considered an indirect plant defence against herbivores. The caterpillar-induced plant volatiles have been reported to repel or attract conspecific adult herbivores. To date however, no volatile signals that either repel or attract conspecific adults under field conditions have been chemically identified. Apple seedlings uniquely released seven compounds including acetic acid, acetic anhydride, benzyl alcohol, benzyl nitrile, indole, 2-phenylethanol, and (E)-nerolidol only when infested by larvae of the light brown apple moth, Epiphyas postvittana. In field tests in New Zealand, a blend of two of these, benzyl nitrile and acetic acid, attracted a large number of conspecific male and female adult moths. In North America, male and female adults of the tortricid, oblique-banded leafroller, Choristoneura rosaceana, were most attracted to a blend of 2-phenylethanol and acetic acid. Both sexes of the eye-spotted bud moth, Spilonota ocellana, were highly attracted to a blend of benzyl nitrile and acetic acid. This study provides the first identification of caterpillar-induced plant volatiles that attract conspecific adult herbivores under natural conditions, challenging the expectation of herbivore avoidance of these induced volatiles. PMID:27892474

Priming of plant resistance by natural compounds. Hexanoic acid as a model

PubMed Central

Aranega-Bou, Paz; de la O Leyva, Maria; Finiti, Ivan; García-Agustín, Pilar; González-Bosch, Carmen

2014-01-01

Some alternative control strategies of currently emerging plant diseases are based on the use of resistance inducers. This review highlights the recent advances made in the characterization of natural compounds that induce resistance by a priming mechanism. These include vitamins, chitosans, oligogalacturonides, volatile organic compounds, azelaic and pipecolic acid, among others. Overall, other than providing novel disease control strategies that meet environmental regulations, natural priming agents are valuable tools to help unravel the complex mechanisms underlying the induced resistance (IR) phenomenon. The data presented in this review reflect the novel contributions made from studying these natural plant inducers, with special emphasis placed on hexanoic acid (Hx), proposed herein as a model tool for this research field. Hx is a potent natural priming agent of proven efficiency in a wide range of host plants and pathogens. It can early activate broad-spectrum defenses by inducing callose deposition and the salicylic acid (SA) and jasmonic acid (JA) pathways. Later it can prime pathogen-specific responses according to the pathogen’s lifestyle. Interestingly, Hx primes redox-related genes to produce an anti-oxidant protective effect, which might be critical for limiting the infection of necrotrophs. Our Hx-IR findings also strongly suggest that it is an attractive tool for the molecular characterization of the plant alarmed state, with the added advantage of it being a natural compound. PMID:25324848

Managing invasive plants in natural areas: Moving beyond weed control

Treesearch

Dean Pearson; Yvette Ortega

2009-01-01

Exotic invasive plants present one of the greatest challenges to natural resource management. These weeds can alter entire communities and ecosystems, substantially degrading important ecosystem services such as forage for wild and domestic herbivores, water and soil quality, recreational values, and wildlife habitat. Traditionally, weed management in natural areas has...

Cameroonian Medicinal Plants: Pharmacology and Derived Natural Products

PubMed Central

Kuete, Victor; Efferth, Thomas

2010-01-01

Many developing countries including Cameroon have mortality patterns that reflect high levels of infectious diseases and the risk of death during pregnancy and childbirth, in addition to cancers, cardiovascular diseases and chronic respiratory diseases that account for most deaths in the developed world. Several medicinal plants are used traditionally for their treatment. In this review, plants used in Cameroonian traditional medicine with evidence for the activities of their crude extracts and/or derived products have been discussed. A considerable number of plant extracts and isolated compounds possess significant antimicrobial, anti-parasitic including antimalarial, anti-proliferative, anti-inflammatory, anti-diabetes, and antioxidant effects. Most of the biologically active compounds belong to terpenoids, phenolics, and alkaloids. Terpenoids from Cameroonian plants showed best activities as anti-parasitic, but rather poor antimicrobial effects. The best antimicrobial, anti-proliferative, and antioxidant compounds were phenolics. In conclusion, many medicinal plants traditionally used in Cameroon to treat various ailments displayed good activities in vitro. This explains the endeavor of Cameroonian research institutes in drug discovery from indigenous medicinal plants. However, much work is still to be done to standardize methodologies and to study the mechanisms of action of isolated natural products. PMID:21833168

Population abundance of Frankliniella occidentalis (Thysanoptera: Thripidae) and natural enemies on plant hosts in central Chile.

PubMed

Ripa, Renato; Funderburk, Joe; Rodriguez, Fernando; Espinoza, Fernanda; Mound, Laurence

2009-04-01

Populations of the invasive Frankliniella occidentalis (Pergande) are serious pests of agricultural crops in the Aconcagua Valley of central Chile. An extensive survey was conducted of 55 plant species in 24 families to identify plant hosts of F. occidentalis and to determine its relative abundance on each host during each season. A more intensive study was conducted on selected plant species serving as reproductive hosts to determine the population dynamics of F. occidentalis and to evaluate the potential importance of Orius species and other natural enemies for controlling F. occidentalis. Adults of F. occidentalis were active during each season of the year inhabiting the flowers of 91% of the sampled plant species in 22 families, and 86% of these plant species in 19 families served as reproductive hosts. The number of host plant species used was greatest in the spring and least in the winter. All of the hosts except Medicago sativa L. were used only when flowering. Populations of F. occidentalis were significantly aggregated in M. sativa in the terminal buds over the leaves when the host was not flowering, and in the flowers, followed by the terminal buds, followed by the leaves when the host was flowering. Larvae were 1.3-2.3 times more abundant on dates when M. sativa was flowering. There were no identifiable patterns in plant hosts based on endemicity or plant family. Most of the plant species used by F. occidentalis were inferior quality hosts where populations either declined or were stable. Populations of F. occidentalis on low-quality hosts generally escaped predation by Orius species and competition by other species of thrips. Only 25% of the food hosts and 28% of the reproductive hosts for F. occidentalis in the extensive survey, respectively, were host plants for Orius. Parasitoids and other predators were not found to be important in suppressing thrips on any of the plant hosts. Populations of F. occidentalis increased on only a few hosts, including M

Use of space for development of commercial plant natural products

NASA Astrophysics Data System (ADS)

Draeger, Norman A.

1997-01-01

Plant experiments conducted in environments where conditions are carefully controlled reveal fundamental information about physiological processes. An important environmental parameter is gravity, the effects of which may be better understood in part through experiments conducted in space. New insights gained can be used to develop commercial plant natural products in industries such as pharmaceuticals and biocontrol.

Discovery and resupply of pharmacologically active plant-derived natural products: A review

PubMed Central

Linder, Thomas; Wawrosch, Christoph; Uhrin, Pavel; Temml, Veronika; Wang, Limei; Schwaiger, Stefan; Heiss, Elke H.; Rollinger, Judith M.; Schuster, Daniela; Breuss, Johannes M.; Bochkov, Valery; Mihovilovic, Marko D.; Kopp, Brigitte; Bauer, Rudolf; Dirsch, Verena M.; Stuppner, Hermann

2016-01-01

Medicinal plants have historically proven their value as a source of molecules with therapeutic potential, and nowadays still represent an important pool for the identification of novel drug leads. In the past decades, pharmaceutical industry focused mainly on libraries of synthetic compounds as drug discovery source. They are comparably easy to produce and resupply, and demonstrate good compatibility with established high throughput screening (HTS) platforms. However, at the same time there has been a declining trend in the number of new drugs reaching the market, raising renewed scientific interest in drug discovery from natural sources, despite of its known challenges. In this survey, a brief outline of historical development is provided together with a comprehensive overview of used approaches and recent developments relevant to plant-derived natural product drug discovery. Associated challenges and major strengths of natural product-based drug discovery are critically discussed. A snapshot of the advanced plant-derived natural products that are currently in actively recruiting clinical trials is also presented. Importantly, the transition of a natural compound from a “screening hit” through a “drug lead” to a “marketed drug” is associated with increasingly challenging demands for compound amount, which often cannot be met by re-isolation from the respective plant sources. In this regard, existing alternatives for resupply are also discussed, including different biotechnology approaches and total organic synthesis. While the intrinsic complexity of natural product-based drug discovery necessitates highly integrated interdisciplinary approaches, the reviewed scientific developments, recent technological advances, and research trends clearly indicate that natural products will be among the most important sources of new drugs also in the future. PMID:26281720

Discovery and resupply of pharmacologically active plant-derived natural products: A review.

PubMed

Atanasov, Atanas G; Waltenberger, Birgit; Pferschy-Wenzig, Eva-Maria; Linder, Thomas; Wawrosch, Christoph; Uhrin, Pavel; Temml, Veronika; Wang, Limei; Schwaiger, Stefan; Heiss, Elke H; Rollinger, Judith M; Schuster, Daniela; Breuss, Johannes M; Bochkov, Valery; Mihovilovic, Marko D; Kopp, Brigitte; Bauer, Rudolf; Dirsch, Verena M; Stuppner, Hermann

2015-12-01

Medicinal plants have historically proven their value as a source of molecules with therapeutic potential, and nowadays still represent an important pool for the identification of novel drug leads. In the past decades, pharmaceutical industry focused mainly on libraries of synthetic compounds as drug discovery source. They are comparably easy to produce and resupply, and demonstrate good compatibility with established high throughput screening (HTS) platforms. However, at the same time there has been a declining trend in the number of new drugs reaching the market, raising renewed scientific interest in drug discovery from natural sources, despite of its known challenges. In this survey, a brief outline of historical development is provided together with a comprehensive overview of used approaches and recent developments relevant to plant-derived natural product drug discovery. Associated challenges and major strengths of natural product-based drug discovery are critically discussed. A snapshot of the advanced plant-derived natural products that are currently in actively recruiting clinical trials is also presented. Importantly, the transition of a natural compound from a "screening hit" through a "drug lead" to a "marketed drug" is associated with increasingly challenging demands for compound amount, which often cannot be met by re-isolation from the respective plant sources. In this regard, existing alternatives for resupply are also discussed, including different biotechnology approaches and total organic synthesis. While the intrinsic complexity of natural product-based drug discovery necessitates highly integrated interdisciplinary approaches, the reviewed scientific developments, recent technological advances, and research trends clearly indicate that natural products will be among the most important sources of new drugs also in the future. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Modern plant metabolomics: Advanced natural product gene discoveries, improved technologies, and future prospects

DOE PAGES

Sumner, Lloyd W.; Lei, Zhentian; Nikolau, Basil J.; ...

2014-10-24

Plant metabolomics has matured and modern plant metabolomics has accelerated gene discoveries and the elucidation of a variety of plant natural product biosynthetic pathways. This study highlights specific examples of the discovery and characterization of novel genes and enzymes associated with the biosynthesis of natural products such as flavonoids, glucosinolates, terpenoids, and alkaloids. Additional examples of the integration of metabolomics with genome-based functional characterizations of plant natural products that are important to modern pharmaceutical technology are also reviewed. This article also provides a substantial review of recent technical advances in mass spectrometry imaging, nuclear magnetic resonance imaging, integrated LC-MS-SPE-NMR formore » metabolite identifications, and x-ray crystallography of microgram quantities for structural determinations. The review closes with a discussion on the future prospects of metabolomics related to crop species and herbal medicine.« less

Bemisia tabaci Q carrying tomato yellow leaf curl virus strongly suppresses host plant defenses

PubMed Central

Shi, Xiaobin; Pan, Huipeng; Zhang, Hongyi; Jiao, Xiaoguo; Xie, Wen; Wu, Qingjun; Wang, Shaoli; Fang, Yong; Chen, Gong; Zhou, Xuguo; Zhang, Youjun

2014-01-01

The concurrence of tomato yellow leaf curl virus (TYLCV) with the spread of its vector Bemisia tabaci Q rather than B in China suggests a more mutualistic relationship between TYLCV and Q. Here, we investigated the hypothesis that viruliferous B and Q have different effects on plant defenses. We found the fecundity of nonviruliferous B, nonviruliferous Q, viruliferous Q and viruliferous B was 11.080, 12.060, 10.760, and 11.220 respectively on plants previously attacked by the other biotype, however, on their respective noninfested control leaves fecundity was 12.000, 10.880, 9.760, and 8.020 respectively. Only viruliferous B had higher fecundity on viruliferous Q-infested plants than on control plants. The longevity of viruliferous B showed the same phenomenon. At 1 d infestion, the jasmonic acid content in leaves noninfested and in leaves infested with nonviruliferous B, nonviruliferous Q, viruliferous B and viruliferous Q was 407.000, 281.333, 301.333, 266.667 and 134.000 ng/g FW, respectively. The JA content was lowest in viruliferous Q-infested leaves. The proteinase inhibitor activity and expression of JA-related upstream gene LOX and downstream gene PI II showed the same trend. The substantial suppression of host defenses by Q carrying TYLCV probably enhances the spread of Q and TYLCV in China. PMID:24912756

Computational genomic identification and functional reconstitution of plant natural product biosynthetic pathways

PubMed Central

2016-01-01

Covering: 2003 to 2016 The last decade has seen the first major discoveries regarding the genomic basis of plant natural product biosynthetic pathways. Four key computationally driven strategies have been developed to identify such pathways, which make use of physical clustering, co-expression, evolutionary co-occurrence and epigenomic co-regulation of the genes involved in producing a plant natural product. Here, we discuss how these approaches can be used for the discovery of plant biosynthetic pathways encoded by both chromosomally clustered and non-clustered genes. Additionally, we will discuss opportunities to prioritize plant gene clusters for experimental characterization, and end with a forward-looking perspective on how synthetic biology technologies will allow effective functional reconstitution of candidate pathways using a variety of genetic systems. PMID:27321668

Comparison of bacterial and fungal communities between natural and planted pine forests in subtropical China.

PubMed

Nie, Ming; Meng, Han; Li, Ke; Wan, Jia-Rong; Quan, Zhe-Xue; Fang, Chang-Ming; Chen, Jia-Kuan; Li, Bo

2012-01-01

To improve our understanding of the changes in bacterial and fungal diversity in natural pine and planted forests in subtropical region of China, we examined bacterial and fungal communities from a native and a nearby planted pine forest of the Mt. Lushan by constructing clone libraries of 16S and 18S rRNA genes. For bacterial communities, Proteobacteria and Acidobacteria were dominant bacterial taxa in both two types of forest soils. The Shannon-Wiener diversity index, rarefaction curve analysis, and LibShuff analysis suggest that these two forests contained similar diversity of bacterial communities. Low soil acidity (pH ≈ 4) of our study forests might be one of the most important selection factors determining growth of acidophilic Acidobacteria and Proteobacteria. However, the natural forest harbored greater level of fungal diversity than the planted forest according to the Shannon-Wiener diversity index and rarefaction curve analysis. Basidiomycota and Ascomycota were dominant fungal taxa in the soils of natural and planted forests, respectively. Our results suggest that fungal community was more sensitive than the bacterial community in characterizing the differences in plant cover impacts on the microbial flora in the natural and planted forests. The natural and planted forests may function differently due to the differences in soil fungal diversity and relative abundance.

Plant landscape design simulating natural community by using AHP method based on TWINSPAN classification

NASA Astrophysics Data System (ADS)

Wang, Li Han

2018-06-01

Taking the forest vegetation in Zijin Mountain (Purple Mountain) Area of Nanjing as the research object, based on the simulation natural and semi natural plant communities, the systematic research on the construction of Nanjing regional plant landscape is carried out by the method such as literature and theory, investigation and evaluation, discussion and reference. On the basis of TWINSPAN classification, the species composition (flora and geographical composition), community structure, species diversity, interspecific relationship and ecological niche of Zijin Mountain natural vegetation are studied and analyzed as a basis for simulation design and planting. Then, from the three levels of ornamental value, resource development and utilization potential and biological characteristics, a comprehensive evaluation system used for wild ornamental plant resources in Zijin Mountain is built. Finally, some suggestions on the planting species of deep forest vegetation in Zijin Mountain are put forward.

The role of type III effectors from Xanthomonas axonopodis pv. manihotis in virulence and suppression of plant immunity.

PubMed

Medina, Cesar Augusto; Reyes, Paola Andrea; Trujillo, Cesar Augusto; Gonzalez, Juan Luis; Bejarano, David Alejandro; Montenegro, Nathaly Andrea; Jacobs, Jonathan M; Joe, Anna; Restrepo, Silvia; Alfano, James R; Bernal, Adriana

2018-03-01

Xanthomonas axonopodis pv. manihotis (Xam) causes cassava bacterial blight, the most important bacterial disease of cassava. Xam, like other Xanthomonas species, requires type III effectors (T3Es) for maximal virulence. Xam strain CIO151 possesses 17 predicted T3Es belonging to the Xanthomonas outer protein (Xop) class. This work aimed to characterize nine Xop effectors present in Xam CIO151 for their role in virulence and modulation of plant immunity. Our findings demonstrate the importance of XopZ, XopX, XopAO1 and AvrBs2 for full virulence, as well as a redundant function in virulence between XopN and XopQ in susceptible cassava plants. We tested their role in pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity (ETI) using heterologous systems. AvrBs2, XopR and XopAO1 are capable of suppressing PTI. ETI suppression activity was only detected for XopE4 and XopAO1. These results demonstrate the overall importance and diversity in functions of major virulence effectors AvrBs2 and XopAO1 in Xam during cassava infection. © 2017 BSPP AND JOHN WILEY & SONS LTD.

Use of space for development of commercial plant natural products

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

Draeger, N.A.

1997-01-01

Plant experiments conducted in environments where conditions are carefully controlled reveal fundamental information about physiological processes. An important environmental parameter is gravity, the effects of which may be better understood in part through experiments conducted in space. New insights gained can be used to develop commercial plant natural products in industries such as pharmaceuticals and biocontrol. {copyright} {ital 1997 American Institute of Physics.}

Antisense suppression of phospholipase D alpha retards abscisic acid- and ethylene-promoted senescence of postharvest Arabidopsis leaves.

PubMed Central

Fan, L; Zheng, S; Wang, X

1997-01-01

Membrane disruption has been proposed to be a key event in plant senescence, and phospholipase D (PLD; EC 3.1.4.4) has been thought to play an important role in membrane deterioration. We recently cloned and biochemically characterized three different PLDs from Arabidopsis. In this study, we investigated the role of the most prevalent phospholipid-hydrolyzing enzyme, PLD alpha, in membrane degradation and senescence in Arabidopsis. The expression of PLD alpha was suppressed by introducing a PLD alpha antisense cDNA fragment into Arabidopsis. When incubated with abscisic acid and ethylene, leaves detached from the PLD alpha-deficient transgenic plants showed a slower rate of senescence than did those from wild-type and transgenic control plants. The retardation of senescence was demonstrated by delayed leaf yellowing, lower ion leakage, greater photosynthetic activity, and higher content of chlorophyll and phospholipids in the PLD alpha antisense leaves than in those of the wild type. Treatment of detached leaves with abscisic acid and ethylene stimulated PLD alpha expression, as indicated by increases in PLD alpha mRNA, protein, and activity. In the absence of abscisic acid and ethylene, however, detached leaves from the PLD alpha-deficient and wild-type plants showed a similar rate of senescence. In addition, the suppression of PLD alpha did not alter natural plant growth and development. These data suggest that PLD alpha is an important mediator in phytohormone-promoted senescence in detached leaves but is not a direct promoter of natural senescence. The physiological relevance of these findings is discussed. PMID:9437863

Predicting Microstegium vimineum invasion in natural plant communities of the southern Blue Ridge Mountains, USA

Treesearch

Dean P. Anderson; Monica G. Turner; Scott M. Pearson; Thomas P. Albright; Robert K. Peet; Ann Wieben

2012-01-01

Shade-tolerant non-native invasive plant species may make deep incursions into natural plant communities, but detecting such species is challenging because occurrences are often sparse. We developed Bayesian models of the distribution of Microstegium vimineum in natural plant communities of the southern Blue Ridge Mountains, USA to address three objectives: (1) to...

Transgenic Strategies for Enhancement of Nematode Resistance in Plants

PubMed Central

Ali, Muhammad A.; Azeem, Farrukh; Abbas, Amjad; Joyia, Faiz A.; Li, Hongjie; Dababat, Abdelfattah A.

2017-01-01

Plant parasitic nematodes (PPNs) are obligate biotrophic parasites causing serious damage and reduction in crop yields. Several economically important genera parasitize various crop plants. The root-knot, root lesion, and cyst nematodes are the three most economically damaging genera of PPNs on crops within the family Heteroderidae. It is very important to devise various management strategies against PPNs in economically important crop plants. Genetic engineering has proven a promising tool for the development of biotic and abiotic stress tolerance in crop plants. Additionally, the genetic engineering leading to transgenic plants harboring nematode resistance genes has demonstrated its significance in the field of plant nematology. Here, we have discussed the use of genetic engineering for the development of nematode resistance in plants. This review article also provides a detailed account of transgenic strategies for the resistance against PPNs. The strategies include natural resistance genes, cloning of proteinase inhibitor coding genes, anti-nematodal proteins and use of RNA interference to suppress nematode effectors. Furthermore, the manipulation of expression levels of genes induced and suppressed by nematodes has also been suggested as an innovative approach for inducing nematode resistance in plants. The information in this article will provide an array of possibilities to engineer resistance against PPNs in different crop plants. PMID:28536595

Transgenic Strategies for Enhancement of Nematode Resistance in Plants.

PubMed

Ali, Muhammad A; Azeem, Farrukh; Abbas, Amjad; Joyia, Faiz A; Li, Hongjie; Dababat, Abdelfattah A

2017-01-01

Plant parasitic nematodes (PPNs) are obligate biotrophic parasites causing serious damage and reduction in crop yields. Several economically important genera parasitize various crop plants. The root-knot, root lesion, and cyst nematodes are the three most economically damaging genera of PPNs on crops within the family Heteroderidae. It is very important to devise various management strategies against PPNs in economically important crop plants. Genetic engineering has proven a promising tool for the development of biotic and abiotic stress tolerance in crop plants. Additionally, the genetic engineering leading to transgenic plants harboring nematode resistance genes has demonstrated its significance in the field of plant nematology. Here, we have discussed the use of genetic engineering for the development of nematode resistance in plants. This review article also provides a detailed account of transgenic strategies for the resistance against PPNs. The strategies include natural resistance genes, cloning of proteinase inhibitor coding genes, anti-nematodal proteins and use of RNA interference to suppress nematode effectors. Furthermore, the manipulation of expression levels of genes induced and suppressed by nematodes has also been suggested as an innovative approach for inducing nematode resistance in plants. The information in this article will provide an array of possibilities to engineer resistance against PPNs in different crop plants.

Effect of sunn hemp (Crotalaria juncea L.) cutting date and planting density on weed suppression in Georgia, USA.

PubMed

Morris, J Bradley; Chase, Carlene; Treadwell, Danielle; Koenig, Rosie; Cho, Alyssa; Morales-Payan, Jose Pable; Murphy, Tim; Antonious, George F

2015-01-01

A field study was conducted in 2008 and 2009 at the USDA, ARS, Plant Genetic Resources Conservation Unit in Griffin, GA, to investigate weed suppression by sunn hemp (Crotalaria juncea L). The objectives were to (1) evaluate the effects of apical meristem removal (AMR) at three dates [5, 6, and 7 wks after planting (WAP) on May 14, 2008 and May 21, 2009] and (2) assess the impact of seeding rates (11, 28, and 45 kg ha(-1)) on weed biomass reduction. Weed species were identified at 4, 8, and 12 wks after sunn hemp planting. Sunn hemp cutting date had no significant effect on weed suppression in 2008 but significant differences for grass weeds at 4, 8, and 12 WAP and for yellow nutsedge at 8 and 12 WAP did occur when compared to the control in 2009. In comparison to the sunn hemp-free control plot in 2009, all three seeding rates had reduced grass weed dry weights at 4, 8, and 12 WAP. The total mass of yellow nutsedge when grown with sunn hemp was reduced compared to the total mass of yellow nutsedge grown in the weedy check for all seeding rates at 8 and 12 WAP. Lower grass weed biomass was observed by 12 WAP for cutting dates and seeding rates during 2008 and 2009. Sunn hemp cutting date and seeding rate reduced branch numbers in both years. The reduction in sunn hemp seeding rates revealed a decrease in weed populations.

Evidence for a plant-associated natural habitat for Cronobacter spp.

PubMed

Schmid, Michael; Iversen, Carol; Gontia, Iti; Stephan, Roger; Hofmann, Andreas; Hartmann, Anton; Jha, Bhavanath; Eberl, Leo; Riedel, Kathrin; Lehner, Angelika

2009-10-01

Cronobacter (Enterobacter sakazakii) species are responsible for rare cases of necrotising enterocolitis and bacteraemia in infants, as well as cases of meningitis with high case fatality rates in neonates and immunocompromised infants. Some physiological features, such as the production of a yellow pigment, the formation of a gum-like extracellular polysaccharide and the ability to persist in a desiccated state, suggest an environmental niche for these organisms. To date, the natural habitat of Cronobacter spp. remains unknown. In this report, the isolation and characterisation of two Cronobacter sakazakii strains from plant roots is described. Also, the root colonisation behaviour of Cronobacter strains originating from clinical and plant sources is assessed. The nine strains investigated showed features often found in plant-associated and rhizosphere microorganisms, including solubilisation of mineral phosphate and production of indole acetic acid. Siderophore production was observed for all except one strain. In addition, the capability to endophytically colonise tomato and maize roots was demonstrated for several strains, either by fluorescence in situ hybridisation, using fluorescently labelled oligonucleotide probes, or by using strains tagged with green fluorescent protein and confocal laser scanning microscopy. The results provide evidence that plants may be the natural habitat of Cronobacter spp.

Inhibition of Th1 and Th17 Cells by Medicinal Plants and Their Derivatives: A Systematic Review.

PubMed

Asadi-Samani, Majid; Bagheri, Nader; Rafieian-Kopaei, Mahmoud; Shirzad, Hedayatollah

2017-08-01

Searching for new natural drugs that are capable of targeting Th1 and Th17 may lead to development of more effective treatments for inflammatory and autoimmune diseases. Most of the natural drugs can be derived from plants that are used in traditional medicine and folk medicine. The aim of this systematic review is to identify and introduce plants or plant derivatives that are effective on inflammatory diseases by inhibiting Th1 and Th17 responses. To achieve this purpose, the search terms herb, herbal medicine, herbal drug, medicinal plant, phytochemical, traditional Chinese medicine, Ayurvedic medicine, natural compound, inflammation, inflammatory diseases, Th1, Th17, T helper 1 or T helper 17 were used separately in Title/Keywords/Abstract in Web of Science and PubMed databases. In articles investigating the effect of the medicinal plants and their derivatives in inhibiting Th1 and Th17 cells, the effects of eight extracts of the medicinal plants, 21 plant-based compounds and some of their derivatives, and eight drugs derived from the medicinal plants' compounds in inhibiting Th1 and Th17 cells were reviewed. The results showed that medicinal plants and their derivates are able to suppress Th17 and Th1 T cell functions as well as cytokine secretion and differentiation. The results can be used to produce herbal drugs that suppress Th, especially Th17, responses. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

The Effector SPRYSEC-19 of Globodera rostochiensis Suppresses CC-NB-LRR-Mediated Disease Resistance in Plants1[C][W][OA

PubMed Central

Postma, Wiebe J.; Slootweg, Erik J.; Rehman, Sajid; Finkers-Tomczak, Anna; Tytgat, Tom O.G.; van Gelderen, Kasper; Lozano-Torres, Jose L.; Roosien, Jan; Pomp, Rikus; van Schaik, Casper; Bakker, Jaap; Goverse, Aska; Smant, Geert

2012-01-01

The potato cyst nematode Globodera rostochiensis invades roots of host plants where it transforms cells near the vascular cylinder into a permanent feeding site. The host cell modifications are most likely induced by a complex mixture of proteins in the stylet secretions of the nematodes. Resistance to nematodes conferred by nucleotide-binding-leucine-rich repeat (NB-LRR) proteins usually results in a programmed cell death in and around the feeding site, and is most likely triggered by the recognition of effectors in stylet secretions. However, the actual role of these secretions in the activation and suppression of effector-triggered immunity is largely unknown. Here we demonstrate that the effector SPRYSEC-19 of G. rostochiensis physically associates in planta with the LRR domain of a member of the SW5 resistance gene cluster in tomato (Lycopersicon esculentum). Unexpectedly, this interaction did not trigger defense-related programmed cell death and resistance to G. rostochiensis. By contrast, agroinfiltration assays showed that the coexpression of SPRYSEC-19 in leaves of Nicotiana benthamiana suppresses programmed cell death mediated by several coiled-coil (CC)-NB-LRR immune receptors. Furthermore, SPRYSEC-19 abrogated resistance to Potato virus X mediated by the CC-NB-LRR resistance protein Rx1, and resistance to Verticillium dahliae mediated by an unidentified resistance in potato (Solanum tuberosum). The suppression of cell death and disease resistance did not require a physical association of SPRYSEC-19 and the LRR domains of the CC-NB-LRR resistance proteins. Altogether, our data demonstrated that potato cyst nematodes secrete effectors that enable the suppression of programmed cell death and disease resistance mediated by several CC-NB-LRR proteins in plants. PMID:22904163

Tumor-suppressive effects of natural-type interferon-β through CXCL10 in melanoma

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

Kobayashi, Hikaru; Nobeyama, Yoshimasa, E-mail: nobederm@jikei.ac.jp; Nakagawa, Hidemi

2015-08-21

Introduction: Type 1 interferon is in widespread use as adjuvant therapy to inhibit melanoma progression. Considering the tumor-suppressive effects of local administration of interferon-β (IFN-β) on lymphatic metastasis, the present study was conducted to identify melanoma-suppressive molecules that are up-regulated by IFN-β treatment of lymphatic endothelial cells. Materials and methods: Lymphatic endothelial cells, fibroblasts, and melanoma cells were treated with natural-type IFN-β, and melanoma cells were treated with CXCL10. Genome-wide oligonucleotide microarray analysis was performed using lymphatic endothelial cells with or without IFN-β treatment. Quantitative real-time reverse transcription-PCR and an enzyme-linked immunosorbent assay were performed to examine CXCL10 expression. Amore » proliferation assay was performed to examine the effects of IFN-β and CXCL10 in melanoma cells. Results: Genome-wide microarray analyses detected CXCL10 as a gene encoding a secretory protein that was up-regulated by IFN-β in lymphatic endothelial cells. IFN-β treatment significantly induced CXCL10 in dermal lymphatic endothelial cells and melanoma cells that are highly sensitive to IFN-β. CXCL10 reduced melanoma cell proliferation in IFN-β-sensitive cells as well as resistant cells. Melanoma cells in which CXCL10 was knocked down were sensitive to IFN-β. CXCR3-B, which encodes the CXCL10 receptor, was up-regulated in melanoma cells with high sensitivity to IFN-β and down-regulated in melanoma cells with medium to low sensitivity. Conclusions: Our data suggest that IFN-β suppresses proliferation and metastasis from the local lymphatic system and melanoma cells via CXCL10. Down-regulation of CXCR3-B by IFN-β may be associated with resistance to IFN-β. - Highlights: • We search melanoma-suppressive molecules induced by IFN-β. • IFN-β induces a high amount of CXCL10 from lymphatic endothelial cells. • CXCL10 induction level in melanoma cells is

Quality of healing of gastric ulcers: Natural products beyond acid suppression

PubMed Central

Kangwan, Napapan; Park, Jong-Min; Kim, Eun-Hee; Hahm, Ki Baik

2014-01-01

Gastric ulcer is a chronic disease featured with unexpected complications, including bleeding, stenosis and perforation, as well as a high incidence of recurrence. Clinical treatments for gastric ulcer have allowed the rapid development of potent anti-ulcer drugs during the last several decades. Gastric ulcer healing is successful with conventional treatments including H2-receptor antagonists, and proton pump inhibitors (PPIs) have been essential for ulcer healing and prevention of complications. Additionally, Helicobacter pylori eradication therapy is effective in reducing ulcer recurrence and leads to physiological changes in the gastric mucosa which affect the ulcer healing process. However, in spite of these advancements, some patients have suffered from recurrence or intractability in spite of continuous anti-ulcer therapy. A new concept of the quality of ulcer healing (QOUH) was initiated that considers the reconstruction of the mucosal structure and its function for preventing ulcer recurrence. Although several gastroprotection provided these achievements of the QOUH, which PPI or other acid suppressants did not accomplish, we found that gastroprotection that originated from natural products, such as a newer formulation from either Artemisia or S-allyl cysteine from garlic, were very effective in the QOUH, as well as improving clinical symptoms with fewer side effects. In this review, we will introduce the importance of the QOUH in ulcer healing and the achievements from natural products. PMID:24891974

Quality of healing of gastric ulcers: Natural products beyond acid suppression.

PubMed

Kangwan, Napapan; Park, Jong-Min; Kim, Eun-Hee; Hahm, Ki Baik

2014-02-15

Gastric ulcer is a chronic disease featured with unexpected complications, including bleeding, stenosis and perforation, as well as a high incidence of recurrence. Clinical treatments for gastric ulcer have allowed the rapid development of potent anti-ulcer drugs during the last several decades. Gastric ulcer healing is successful with conventional treatments including H2-receptor antagonists, and proton pump inhibitors (PPIs) have been essential for ulcer healing and prevention of complications. Additionally, Helicobacter pylori eradication therapy is effective in reducing ulcer recurrence and leads to physiological changes in the gastric mucosa which affect the ulcer healing process. However, in spite of these advancements, some patients have suffered from recurrence or intractability in spite of continuous anti-ulcer therapy. A new concept of the quality of ulcer healing (QOUH) was initiated that considers the reconstruction of the mucosal structure and its function for preventing ulcer recurrence. Although several gastroprotection provided these achievements of the QOUH, which PPI or other acid suppressants did not accomplish, we found that gastroprotection that originated from natural products, such as a newer formulation from either Artemisia or S-allyl cysteine from garlic, were very effective in the QOUH, as well as improving clinical symptoms with fewer side effects. In this review, we will introduce the importance of the QOUH in ulcer healing and the achievements from natural products.

Plant-Derived Natural Products as Sources of Anti-Quorum Sensing Compounds

PubMed Central

Koh, Chong-Lek; Sam, Choon-Kook; Yin, Wai-Fong; Tan, Li Ying; Krishnan, Thiba; Chong, Yee Meng; Chan, Kok-Gan

2013-01-01

Quorum sensing is a system of stimuli and responses in relation to bacterial cell population density that regulates gene expression, including virulence determinants. Consequently, quorum sensing has been an attractive target for the development of novel anti-infective measures that do not rely on the use of antibiotics. Anti-quorum sensing has been a promising strategy to combat bacterial infections as it is unlikely to develop multidrug resistant pathogens since it does not impose any selection pressure. A number of anti-quorum sensing approaches have been documented and plant-based natural products have been extensively studied in this context. Plant matter is one of the major sources of chemicals in use today in various industries, ranging from the pharmaceutical, cosmetic, and food biotechnology to the textile industries. Just like animals and humans, plants are constantly exposed to bacterial infections, it is therefore logical to expect that plants have developed sophisticated of chemical mechanisms to combat pathogens. In this review, we have surveyed the various types of plant-based natural products that exhibit anti-quorum sensing properties and their anti-quorum sensing mechanisms. PMID:23669710

Checklist of the vascular plants of Steamboat Mountain Research Natural Area.

Treesearch

S. Reid Schuller; Robert E. Frenkel

1981-01-01

Lists 237 vascular plant taxa found in the 570-hectare Steamboat Mountain Research Natural Area. Notes on habitats, community types, and abundance are included for most taxa. This research note provides scientists, educators, and land managers with baseline information on the presence, location, and abundance of vascular plants within the Steamboat Mountain Research...

Soil-to-plant transfer factors of natural radionuclides (226Ra and 40K) in selected Thai medicinal plants.

PubMed

Saenboonruang, Kiadtisak; Phonchanthuek, Endu; Prasandee, Kamonkhuan

2018-04-01

A soil-to-plant transfer factor (TF) is an important parameter that could be used to estimate radionuclides levels in medicinal plants. This work reports concentrations of natural radionuclides ( 226 Ra and 40 K) and TFs in six Thai medicinal plants grown in central Thailand using an HPGe gamma ray spectrometer. Either root, leaf, or flower parts of each medicinal plant were selected for use in the investigation according to their practical uses in traditional medicine. The results showed that due to K being essential in plants, 40 K had higher arithmetic means of activity concentrations and geometric means of TFs (geometric standard deviations in parentheses) of 610 ± 260 Bq kg -1 dry weight (DW) and 2.0 (1.4), respectively, than 226 Ra, which had the activity concentrations and TFs of 4.8 ± 2.6 Bq kg -1 DW and 0.17 (1.8), respectively. The results also showed that the leaves of medicinal plants had higher activity concentrations and TFs than root and flower parts, probably due to higher metabolic activities in leaves. Furthermore, there was good agreement between the results from the current work and other similar reports on medicinal plants. The information obtained from this work could strengthen knowledge of natural radionuclides in plants and particularly increase available TF data on Thai medicinal plants. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effect of stimulation by foliage plant display images on prefrontal cortex activity: a comparison with stimulation using actual foliage plants.

PubMed

Igarashi, Miho; Song, Chorong; Ikei, Harumi; Miyazaki, Yoshifumi

2015-01-01

Natural scenes like forests and flowers evoke neurophysiological responses that can suppress anxiety and relieve stress. We examined whether images of natural objects can elicit neural responses similar to those evoked by real objects by comparing the activation of the prefrontal cortex during presentation of real foliage plants with a projected image of the same foliage plants. Oxy-hemoglobin concentrations in the prefrontal cortex were measured using time-resolved near-infrared spectroscopy while the subjects viewed the real plants or a projected image of the same plants. Compared with a projected image of foliage plants, viewing the actual foliage plants significantly increased oxy-hemoglobin concentrations in the prefrontal cortex. However, using the modified semantic differential method, subjective emotional response ratings ("comfortable vs. uncomfortable" and "relaxed vs. awakening") were similar for both stimuli. The frontal cortex responded differently to presentation of actual plants compared with images of these plants even when the subjective emotional response was similar. These results may help explain the physical and mental health benefits of urban, domestic, and workplace foliage. © 2014 The Authors. Journal of Neuroimaging published by the American Society of Neuroimaging.

Plants as natural antioxidants for meat products

NASA Astrophysics Data System (ADS)

Tomović, V.; Jokanović, M.; Šojić, B.; Škaljac, S.; Ivić, M.

2017-09-01

The meat industry is demanding antioxidants from natural sources to replace synthetic antioxidants because of the negative health consequences or beliefs regarding some synthetic ones. Plants materials provide good alternatives. Spices and herbs, generally used for their flavouring characteristics, can be added to meat products in various forms: whole, ground, or as isolates from their extracts. These natural antioxidants contain some active compounds, which exert antioxidative potential in meat products. This antioxidant activity is most often due to phenolic acids, phenolic diterpenes, flavonoids and volatile oils. Each of these compounds often has strong H-donating activity, thus making them extremely effective antioxidants; some compounds can chelate metals and donate H to oxygen radicals, thus slowing oxidation via two mechanisms. Numerous studies have demonstrated the efficacy of natural antioxidants when used in meat products. Based on this literature review, it can be concluded that natural antioxidants are added to fresh and processed meat and meat products to delay, retard, or prevent lipid oxidation, retard development of off-flavours (rancidity), improve colour stability, improve microbiological quality and extend shelf-life, without any damage to the sensory or nutritional properties.

NPACT: Naturally Occurring Plant-based Anti-cancer Compound-Activity-Target database

PubMed Central

Mangal, Manu; Sagar, Parul; Singh, Harinder; Raghava, Gajendra P. S.; Agarwal, Subhash M.

2013-01-01

Plant-derived molecules have been highly valued by biomedical researchers and pharmaceutical companies for developing drugs, as they are thought to be optimized during evolution. Therefore, we have collected and compiled a central resource Naturally Occurring Plant-based Anti-cancer Compound-Activity-Target database (NPACT, http://crdd.osdd.net/raghava/npact/) that gathers the information related to experimentally validated plant-derived natural compounds exhibiting anti-cancerous activity (in vitro and in vivo), to complement the other databases. It currently contains 1574 compound entries, and each record provides information on their structure, manually curated published data on in vitro and in vivo experiments along with reference for users referral, inhibitory values (IC50/ED50/EC50/GI50), properties (physical, elemental and topological), cancer types, cell lines, protein targets, commercial suppliers and drug likeness of compounds. NPACT can easily be browsed or queried using various options, and an online similarity tool has also been made available. Further, to facilitate retrieval of existing data, each record is hyperlinked to similar databases like SuperNatural, Herbal Ingredients’ Targets, Comparative Toxicogenomics Database, PubChem and NCI-60 GI50 data. PMID:23203877

Contrasting natural regeneration and tree planting in fourteen North American cities

Treesearch

David J. Nowak

2012-01-01

Field data from randomly located plots in 12 cities in the United States and Canada were used to estimate the proportion of the existing tree population that was planted or occurred via natural regeneration. In addition, two cities (Baltimore and Syracuse) were recently re-sampled to estimate the proportion of newly established trees that were planted. Results for the...

Use of naturally growing aquatic plants for wastewater purification.

PubMed

Zimmels, Y; Kirzhner, F; Roitman, S

2004-01-01

This paper examines potential uses of naturally growing aquatic plants for wastewater purification. These plants enhance the removal of pollutants by consuming part of them in the form of plant nutrients. This applies to urban and agricultural wastewater, in particular, where treatment units of different sizes can be applied at the pollution source. The effectiveness of wastewater purification by different plants was tested on laboratory and pilot scales. The growth rate of the plants was related to the wastewater content in the water. Batch and semicontinuous experiments verified that the plants are capable of decreasing all tested indicators for water quality to levels that permit the use of the purified water for irrigation. This applies to biochemical oxygen demand (BOD), chemical oxygen demand, total suspended solids. pH, and turbidity. In specific cases, the turbidity reached the level of drinking water. Comparison of BOD concentrations with typical levels in water treatment facilities across the country indicates the effectiveness of water purification with plants. A major effect of treatment with plants was elimination of the disturbing smell from the wastewater. It is shown that mixtures of wastewater and polluted water from the Kishon River are amenable in varying degrees to treatment by the plants. The higher the wastewater content in the mixture, the more effective the treatment by the plants. In this context, a scheme for rehabilitation and restoration of the Kishon River is presented and technical and economical aspects of the purification technology are considered.

Uptake of the natural radioactive gas radon by an epiphytic plant.

PubMed

Li, Peng; Zhang, Ruiwen; Gu, Mintian; Zheng, Guiling

2018-01-15

Radon ( 222 Rn) is a natural radioactive gas and the major radioactive contributor to human exposure. The present effective ways to control Rn contamination are ventilation and adsorption with activated carbon. Plants are believed to be negligible in reducing airborne Rn. Here, we found epiphytic Tillandsia brachycaulos (Bromeliaceae) was effective in reducing airborne Rn via the leaves. Rn concentrations in the Rn chamber after Tillandsia plant treatments decreased more than those in the natural situation. The specialized foliar trichomes densely covering Tillandsia leaves play a major role in the uptake of Rn because the amplified rough leaf surface area facilitates deposition of Rn progeny particles and the powdery epicuticular wax layer of foliar trichomes uptakes liposoluble Rn. The results provide us a new ecological strategy for Rn contamination control, and movable epiphytic Tillandsia plants can be applied widely in Rn removal systems. Copyright © 2017 Elsevier B.V. All rights reserved.

Expression of the SIN3 homologue from banana, MaSIN3, suppresses ABA responses globally during plant growth in Arabidopsis.

PubMed

Luxmi, Raj; Garg, Rashmi; Srivastava, Sudhakar; Sane, Aniruddha P

2017-11-01

The SIN3 family of co-repressors is a family of highly conserved eukaryotic repressor proteins that regulates diverse functions in yeasts and animals but remains largely uncharacterized functionally even in plants like Arabidopsis. The sole SIN3 homologue in banana, MaSIN3, was identified as a 1408 amino acids, nuclear localized protein conserved to other SIN3s in the PAH, HID and HCR domains. Interestingly, MaSIN3 over-expression in Arabidopsis mimics a state of reduced ABA responses throughout plant development affecting growth processes such as germination, root growth, stomatal closure and water loss, flowering and senescence. The reduction in ABA responses is not due to reduced ABA levels but due to suppression of expression of several transcription factors mediating ABA responses. Transcript levels of negative regulators of germination (ABI3, ABI5, PIL5, RGL2 and RGL3) are reduced post-imbibition while those responsible for GA biosynthesis are up-regulated in transgenic MaSIN3 over-expressers. ABA-associated transcription factors are also down-regulated in response to ABA treatment. The HDAC inhibitors, SAHA and sodium butyrate, in combination with ABA differentially suppress germination in control and transgenic lines suggesting the recruitment by MaSIN3 of HDACs involved in suppression of ABA responses in different processes. The studies provide an insight into the ability of MaSIN3 to specifically affect a subset of developmental processes governed largely by ABA. Copyright © 2017 Elsevier B.V. All rights reserved.

Proof of the Wave Nature of Plants

NASA Astrophysics Data System (ADS)

Wagner, Orvin

2008-03-01

I assume plants operate with a set of frequencies. These frequencies and the means of these frequencies are equal in all directions. We can then write (vh/λ)avh=(vv/λ)avv where the subscripts h and v represent horizontal and vertical respectively and av is average,. or vv/vh=(1/λh)av/(1/λv)av. I use an internodal spacing as λ/2 or the the distance between adjacent branches, leaves, etc. The ratios, vv/vh, are ratios of small integers for sufficient samplings. For example, for Ponderosa pine the ratio is 3/1 or for delicious apple 4/3. Note that these ratios represent the shape of the tree or other plant and their interactions with gravity. These ratios are derivable by other means such as use the ratio of # of horizontal needles per unit length from a horizontal sample to the # of needles per unit length from a vertical sample from p-pine. Or measure the vertical and horizontal velocities. My literature provides many other proofs of the wave nature of plants. I suggest that the waves in and related waves outside of plants (outside 4.9 m/s) are a dark matter related since they travel at such low velocities. See my present web site at home.budget.net/˜oedphd.

Biosynthesis and molecular actions of specialized 1,4-naphthoquinone natural products produced by horticultural plants

PubMed Central

Widhalm, Joshua R; Rhodes, David

2016-01-01

The 1,4-naphthoquinones (1,4-NQs) are a diverse group of natural products found in every kingdom of life. Plants, including many horticultural species, collectively synthesize hundreds of specialized 1,4-NQs with ecological roles in plant–plant (allelopathy), plant–insect and plant–microbe interactions. Numerous horticultural plants producing 1,4-NQs have also served as sources of traditional medicines for hundreds of years. As a result, horticultural species have been at the forefront of many basic studies conducted to understand the metabolism and function of specialized plant 1,4-NQs. Several 1,4-NQ natural products derived from horticultural plants have also emerged as promising scaffolds for developing new drugs. In this review, the current understanding of the core metabolic pathways leading to plant 1,4-NQs is provided with additional emphasis on downstream natural products originating from horticultural species. An overview on the biochemical mechanisms of action, both from an ecological and pharmacological perspective, of 1,4-NQs derived from horticultural plants is also provided. In addition, future directions for improving basic knowledge about plant 1,4-NQ metabolism are discussed. PMID:27688890

Search for bioactive natural products from medicinal plants of Bangladesh.

PubMed

Ahmed, Firoj; Sadhu, Samir Kumar; Ishibashi, Masami

2010-10-01

In our continuous search for bioactive natural products from natural resources, we explored medicinal plants of Bangladesh, targeting cancer-related tumor necrosis factor-related apoptosis-inducing ligand-signaling pathway, along with some other biological activities such as prostaglandin inhibitory activity, 1,1-diphenyl-2-picrylhydrazyl free-radical-scavenging activity, and cell growth inhibitory activity. Along with this, we describe a short field study on Sundarbans mangrove forests, Bangladesh, in the review.

Phytohormonal basis for the plant growth promoting action of naturally occurring biostimulators.

PubMed

Kurepin, Leonid V; Zaman, Mohammad; Pharis, Richard P

2014-07-01

There is increasing interest in the use of naturally occurring 'biostimulators' for enhancing the growth of agricultural and horticultural crops. Bacteria, fungi and protozoa, as well as marine algae-based seaweed extracts, can produce or contain biostimulators. The activity of biostimulators to promote plant growth is often attributed to their ability to directly or indirectly provide mineral nutrients (mostly N, but also P, S and other macro- and micro-nutrients) to plants. Alternatively, biostimulators are postulated to increase the plant's ability to assimilate these mineral nutrients, often in return for photo-assimilates (as occurs with certain bacteria and fungi associations). Although optimal growth of plants depends on the availability of adequate mineral nutritients, that growth (and also development, including reproduction) is also regulated by plant hormones (phytohormones), including gibberellins, auxins and cytokinins. This review describes and discusses the evidence that the presence or application of biostimulators also increases plant growth directly via phytohormone action and also influences the plant's ability to control its own hormone biosynthesis and homeostasis. Finally, it discusses the need for a better understanding of the role(s) that are played by the naturally occurring biostimulators associated with the plant in the crop field. It is suggested that better understanding will allow for optimal crop yield returns, since disruptions of phytohormone homeostasis in plant organs and tissues can yield either beneficial or sub-optimal outcomes. © 2013 Society of Chemical Industry.

Hepatitis C Virus Induces Regulatory T Cells by Naturally Occurring Viral Variants to Suppress T Cell Responses

PubMed Central

Cusick, Matthew F.; Schiller, Jennifer J.; Gill, Joan C.; Eckels, David D.

2011-01-01

Regulatory T cell markers are increased in chronically infected individuals with the hepatitis C virus (HCV), but to date, the induction and maintenance of Tregs in HCV infection has not been clearly defined. In this paper, we demonstrate that naturally occurring viral variants suppress T cell responses to cognate NS3358-375 in an antigen-specific manner. Of four archetypal variants, S370P induced regulatory T cell markers in comparison to NS3358-375-stimulated CD4 T cells. Further, the addition of variant-specific CD4 T cells back into a polyclonal culture in a dose-dependent manner inhibited the T cell response. These results suggest that HCV is able to induce antigen-specific regulatory T cells to suppress the antiviral T cell response in an antigen-specific manner, thus contributing to a niche within the host that could be conducive to HCV persistence. PMID:21197453

Soil Conditions That Can Alter Natural Suppression of Escherichia coli O157:H7 in Ohio Specialty Crop Soils

PubMed Central

Williams, Michele L.; LeJeune, Jeffrey T.

2015-01-01

Food-borne pathogen persistence in soil fundamentally affects the production of safe vegetables and small fruits. Interventions that reduce pathogen survival in soil would have positive impacts on food safety by minimizing preharvest contamination entering the food chain. Laboratory-controlled studies determined the effects of soil pH, moisture content, and soil organic matter (SOM) on the survivability of this pathogen through the creation of single-parameter gradients. Longitudinal field-based studies were conducted in Ohio to quantify the extent to which field soils suppressed Escherichia coli O157:H7 survival. In all experiments, heat-sensitive microorganisms were responsible for the suppression of E. coli O157 in soil regardless of the chemical composition of the soil. In laboratory-based studies, soil pH and moisture content were primary drivers of E. coli O157 survival, with increases in pH after 48 h (P = 0.02) and decreases in moisture content after 48 h (P = 0.007) significantly increasing the log reduction of E. coli O157 numbers. In field-based experiments, E. coli O157 counts from both heated and unheated samples were sensitive to both season (P = 0.004 for heated samples and P = 0.001 for unheated samples) and region (P = 0.002 for heated samples and P = 0.001 for unheated samples). SOM was observed to be a more significant driver of pathogen suppression than the other two factors after 48 h at both planting and harvest (P = 0.002 at planting and P = 0.058 at harvest). This research reinforces the need for both laboratory-controlled experiments and longitudinal field-based experiments to unravel the complex relationships controlling the survival of introduced organisms in soil. PMID:25934621

Potato plants with genetically engineered tropane alkaloid precursors.

PubMed

Küster, Nadine; Rosahl, Sabine; Dräger, Birgit

2017-02-01

Solanum tuberosum tropinone reductase I reduced tropinone in vivo. Suppression of tropinone reductase II strongly reduced calystegines in sprouts. Overexpression of putrescine N -methyltransferase did not alter calystegine accumulation. Calystegines are hydroxylated alkaloids formed by the tropane alkaloid pathway. They accumulate in potato (Solanum tuberosum L., Solanaceae) roots and sprouting tubers. Calystegines inhibit various glycosidases in vitro due to their sugar-mimic structure, but functions of calystegines in plants are not understood. Enzymes participating in or competing with calystegine biosynthesis, including putrescine N-methyltransferase (PMT) and tropinone reductases (TRI and TRII), were altered in their activity in potato plants by RNA interference (RNAi) and by overexpression. The genetically altered potato plants were investigated for the accumulation of calystegines and for intermediates of their biosynthesis. An increase in N-methylputrescine provided by DsPMT expression was not sufficient to increase calystegine accumulation. Overexpression and gene knockdown of StTRI proved that S. tuberosum TRI is a functional tropinone reductase in vivo, but no influence on calystegine accumulation was observed. When StTRII expression was suppressed by RNAi, calystegine formation was severely compromised in the transformed plants. Under phytochamber and green house conditions, the StTRII RNAi plants did not show phenotypic alterations. Further investigation of calystegines function in potato plants under natural conditions is enabled by the calystegine deprived StTRII RNAi plants.

Bacteria Associated to Plants Naturally Selected in a Historical PCB Polluted Soil Show Potential to Sustain Natural Attenuation.

PubMed

Vergani, Lorenzo; Mapelli, Francesca; Marasco, Ramona; Crotti, Elena; Fusi, Marco; Di Guardo, Antonio; Armiraglio, Stefano; Daffonchio, Daniele; Borin, Sara

2017-01-01

The exploitation of the association between plants and microorganisms is a promising approach able to boost natural attenuation processes for soil clean-up in vast polluted areas characterized by mixed chemical contamination. We aimed to explore the selection of root-associated bacterial communities driven by different plant species spontaneously established in abandoned agricultural soils within a historical polluted site in north Italy. The site is highly contaminated by chlorinated persistent organic pollutants, mainly constituted by polychlorobiphenyls (PCBs), together with heavy metals and metalloids, in variable concentrations and uneven distribution. The overall structure of the non-vegetated and root-associated soil fractions bacterial communities was described by high-throughput sequencing of the 16S rRNA gene, and a collection of 165 rhizobacterial isolates able to use biphenyl as unique carbon source was assayed for plant growth promotion (PGP) traits and bioremediation potential. The results showed that the recruitment of specific bacterial communities in the root-associated soil fractions was driven by both soil fractions and plant species, explaining 21 and 18% of the total bacterial microbiome variation, respectively. PCR-based detection in the soil metagenome of bacterial bphA gene, encoding for the biphenyl dioxygenase α subunit, indicated that the soil in the site possesses metabolic traits linked to PCB degradation. Biphenyl-utilizing bacteria isolated from the rhizosphere of the three different plant species showed low phylogenetic diversity and well represented functional traits, in terms of PGP and bioremediation potential. On average, 72% of the strains harbored the bphA gene and/or displayed catechol 2,3-dioxygenase activity, involved in aromatic ring cleavage. PGP traits, including 1-aminocyclopropane-1-carboxylic acid deaminase activity potentially associated to plant stress tolerance induction, were widely distributed among the isolates

Bacteria Associated to Plants Naturally Selected in a Historical PCB Polluted Soil Show Potential to Sustain Natural Attenuation

PubMed Central

Vergani, Lorenzo; Mapelli, Francesca; Marasco, Ramona; Crotti, Elena; Fusi, Marco; Di Guardo, Antonio; Armiraglio, Stefano; Daffonchio, Daniele; Borin, Sara

2017-01-01

The exploitation of the association between plants and microorganisms is a promising approach able to boost natural attenuation processes for soil clean-up in vast polluted areas characterized by mixed chemical contamination. We aimed to explore the selection of root-associated bacterial communities driven by different plant species spontaneously established in abandoned agricultural soils within a historical polluted site in north Italy. The site is highly contaminated by chlorinated persistent organic pollutants, mainly constituted by polychlorobiphenyls (PCBs), together with heavy metals and metalloids, in variable concentrations and uneven distribution. The overall structure of the non-vegetated and root-associated soil fractions bacterial communities was described by high-throughput sequencing of the 16S rRNA gene, and a collection of 165 rhizobacterial isolates able to use biphenyl as unique carbon source was assayed for plant growth promotion (PGP) traits and bioremediation potential. The results showed that the recruitment of specific bacterial communities in the root-associated soil fractions was driven by both soil fractions and plant species, explaining 21 and 18% of the total bacterial microbiome variation, respectively. PCR-based detection in the soil metagenome of bacterial bphA gene, encoding for the biphenyl dioxygenase α subunit, indicated that the soil in the site possesses metabolic traits linked to PCB degradation. Biphenyl-utilizing bacteria isolated from the rhizosphere of the three different plant species showed low phylogenetic diversity and well represented functional traits, in terms of PGP and bioremediation potential. On average, 72% of the strains harbored the bphA gene and/or displayed catechol 2,3-dioxygenase activity, involved in aromatic ring cleavage. PGP traits, including 1-aminocyclopropane-1-carboxylic acid deaminase activity potentially associated to plant stress tolerance induction, were widely distributed among the isolates

PSTha5a23, a candidate effector from the obligate biotrophic pathogen Puccinia striiformis f. sp. tritici, is involved in plant defense suppression and rust pathogenicity.

PubMed

Cheng, Yulin; Wu, Kuan; Yao, Juanni; Li, Shumin; Wang, Xiaojie; Huang, Lili; Kang, Zhensheng

2017-05-01

During the infection of host plants, pathogens can deliver virulence-associated 'effector' proteins to promote plant susceptibility. However, little is known about effector function in the obligate biotrophic pathogen Puccinia striiformis f. sp. tritici (Pst) that is an important fungal pathogen in wheat production worldwide. Here, they report their findings on an in planta highly induced candidate effector from Pst, PSTha5a23. The PSTha5a23 gene is unique to Pst and shows a low level of intra-species polymorphism. It has a functional N-terminal signal peptide and is translocated to the host cytoplasm after infection. Overexpression of PSTha5a23 in Nicotiana benthamiana was found to suppress the programmed cell death triggered by BAX, PAMP-INF1 and two resistance-related mitogen-activated protein kinases (MKK1 and NPK1). Overexpression of PSTha5a23 in wheat also suppressed pattern-triggered immunity (PTI)-associated callose deposition. In addition, silencing of PSTha5a23 did not change Pst virulence phenotypes; however, overexpression of PSTha5a23 significantly enhanced Pst virulence in wheat. These results indicate that the Pst candidate effector PSTha5a23 plays an important role in plant defense suppression and rust pathogenicity, and also highlight the utility of gene overexpression in plants as a tool for studying effectors from obligate biotrophic pathogens. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

Harnessing Biomedical Natural Language Processing Tools to Identify Medicinal Plant Knowledge from Historical Texts.

PubMed

Sharma, Vivekanand; Law, Wayne; Balick, Michael J; Sarkar, Indra Neil

2017-01-01

The growing amount of data describing historical medicinal uses of plants from digitization efforts provides the opportunity to develop systematic approaches for identifying potential plant-based therapies. However, the task of cataloguing plant use information from natural language text is a challenging task for ethnobotanists. To date, there have been only limited adoption of informatics approaches used for supporting the identification of ethnobotanical information associated with medicinal uses. This study explored the feasibility of using biomedical terminologies and natural language processing approaches for extracting relevant plant-associated therapeutic use information from historical biodiversity literature collection available from the Biodiversity Heritage Library. The results from this preliminary study suggest that there is potential utility of informatics methods to identify medicinal plant knowledge from digitized resources as well as highlight opportunities for improvement.

Harnessing Biomedical Natural Language Processing Tools to Identify Medicinal Plant Knowledge from Historical Texts

PubMed Central

Sharma, Vivekanand; Law, Wayne; Balick, Michael J.; Sarkar, Indra Neil

2017-01-01

The growing amount of data describing historical medicinal uses of plants from digitization efforts provides the opportunity to develop systematic approaches for identifying potential plant-based therapies. However, the task of cataloguing plant use information from natural language text is a challenging task for ethnobotanists. To date, there have been only limited adoption of informatics approaches used for supporting the identification of ethnobotanical information associated with medicinal uses. This study explored the feasibility of using biomedical terminologies and natural language processing approaches for extracting relevant plant-associated therapeutic use information from historical biodiversity literature collection available from the Biodiversity Heritage Library. The results from this preliminary study suggest that there is potential utility of informatics methods to identify medicinal plant knowledge from digitized resources as well as highlight opportunities for improvement. PMID:29854223

Rehabilitation of Understocked Loblolly-Shortleaf Pine Stands - II. Development of Intermediate and Suppressed Trees Following Release in Natural Stands

Treesearch

James B. Baker; Michael G. Shelton

1998-01-01

Development of 86 intermediate and suppressed loblolly pine (Pinus taeda L.) trees, that had been recently released from overtopping pines and hardwoods, was monitored over a 15 year period. The trees were growing in natural stands on good sites (site index = 90 ft at 50 years) that had been recently cut to stocking levels ranging from 10 to 50 percent. At time of...

Shifts in plant foliar and floral metabolomes in response to the suppression of the associated microbiota.

PubMed

Gargallo-Garriga, Albert; Sardans, Jordi; Pérez-Trujillo, Míriam; Guenther, Alex; Llusià, Joan; Rico, Laura; Terradas, Jaume; Farré-Armengol, Gerard; Filella, Iolanda; Parella, Teodor; Peñuelas, Josep

2016-04-06

The phyllospheric microbiota is assumed to play a key role in the metabolism of host plants. Its role in determining the epiphytic and internal plant metabolome, however, remains to be investigated. We analyzed the Liquid Chromatography-Mass Spectrometry (LC-MS) profiles of the epiphytic and internal metabolomes of the leaves and flowers of Sambucus nigra with and without external antibiotic treatment application. The epiphytic metabolism showed a degree of complexity similar to that of the plant organs. The suppression of microbial communities by topical applications of antibiotics had a greater impact on the epiphytic metabolome than on the internal metabolomes of the plant organs, although even the latter changed significantly both in leaves and flowers. The application of antibiotics decreased the concentration of lactate in both epiphytic and organ metabolomes, and the concentrations of citraconic acid, acetyl-CoA, isoleucine, and several secondary compounds such as terpenes and phenols in the epiphytic extracts. The metabolite pyrogallol appeared in the floral epiphytic community only after the treatment. The concentrations of the amino acid precursors of the ketoglutarate-synthesis pathway tended to decrease in the leaves and to increase in the foliar epiphytic extracts. These results suggest that anaerobic and/or facultative anaerobic bacteria were present in high numbers in the phyllosphere and in the apoplasts of S. nigra. The results also show that microbial communities play a significant role in the metabolomes of plant organs and could have more complex and frequent mutualistic, saprophytic, and/or parasitic relationships with internal plant metabolism than currently assumed.

Strategies for engineering plant natural products: the iridoid-derived monoterpene indole alkaloids of Catharanthus roseus.

PubMed

O'Connor, Sarah E

2012-01-01

The manipulation of pathways to make unnatural variants of natural compounds, a process often termed combinatorial biosynthesis, has been robustly successful in prokaryotic systems. The development of approaches to generate new-to-nature compounds from plant-based pathways is, in comparison, much less advanced. Success will depend on the specific chemistry of the pathway, as well as on the suitability of the plant system for transformation and genetic manipulation. As plant pathways are elucidated, and can be heterologously expressed in hosts that are more amenable to genetic manipulation, biosynthetic production of new-to-nature compounds from plant pathways will become more widespread. In this chapter, some of the key strategies that have been developed for metabolic engineering of plant pathways, namely directed biosynthesis, mutasynthesis, and pathway incorporation of engineered enzymes are highlighted. The iridoid-derived monoterpene indole alkaloids from C. roseus, which are the focus of this chapter, provide an excellent system for developing these strategies. Copyright © 2012 Elsevier Inc. All rights reserved.

Suppression of the invasive plant mile-a-minute (Mikania micrantha) by local crop sweet potato (Ipomoea batatas) by means of higher growth rate and competition for soil nutrients.

PubMed

Shen, Shicai; Xu, Gaofeng; Clements, David Roy; Jin, Guimei; Chen, Aidong; Zhang, Fudou; Kato-Noguchi, Hisashi

2015-01-28

There are a variety of ways of increasing crop diversity to increase agricultural sustainability and in turn having a positive influence on nearby natural ecosystems. Competitive crops may provide potent management tools against invasive plants. To elucidate the competitive mechanisms between a sweet potato crop (Ipomoea batatas) and an invasive plant, mile-a-minute (Mikania micrantha), field experiments were carried out in Longchuan County of Yunnan Province, Southwest China, utilizing a de Wit replacement series. The trial incorporated seven ratios of sweet potato and mile-a-minute plants in 25 m(2) plots. In monoculture, the total biomass, biomass of adventitious root, leafstalk length, and leaf area of sweet potato were all higher than those of mile-a-minute, and in mixed culture the plant height, branch, leaf, stem node, adventitious root, flowering and biomass of mile-a-minute were suppressed significantly (P < 0.05). The relative yield (RY) of mile-a-minute and sweet potato was less than 1.0 in mixed culture, indicating that intraspecific competition was less than interspecific competition. The competitive balance index of sweet potato demonstrated a higher competitive ability than mile-a-minute. Except pH, other soil nutrient contents of initial soil (CK) were significantly higher than those of seven treatments. The concentrations of soil organic matter, total N, total K, available N, available P, available K, exchange Ca, exchange Mg, available Mn, and available B were significantly greater (P < 0.05) in mile-a-minute monoculture soil than in sweet potato monoculture soil, and were reduced by the competition of sweet potato in the mixture. Evidently sweet potato has a competitive advantage in terms of plant growth characteristics and greater absorption of soil nutrients. Thus, planting sweet potato is a promising technique for reducing infestations of mile-a-minute, providing weed management benefits and economic returns from harvest of sweet

Exploring growth-defence trade-offs in Arabidopsis: phytochrome B inactivation requires JAZ10 to suppress plant immunity but not to trigger shade-avoidance responses.

PubMed

Cerrudo, Ignacio; Caliri-Ortiz, M Emilia; Keller, Mercedes M; Degano, M Eugenia; Demkura, Patricia V; Ballaré, Carlos L

2017-05-01

Under conditions that involve a high risk of competition for light among neighbouring plants, shade-intolerant species often display increased shoot elongation and greater susceptibility to pathogens and herbivores. The functional links between morphological and defence responses to crowding are not well understood. In Arabidopsis, the protein JAZ10 is thought to play a key role connecting the inactivation of the photoreceptor phytochrome B (phyB), which takes place under competition for light, with the repression of jasmonate-mediated plant defences. Here, we show that a null mutation of the JAZ10 gene in Arabidopsis did not affect plant growth nor did it suppress the shade-avoidance responses elicited by phyB inactivation. However, the jaz10 mutation restored many of the defence traits that are missing in the phyB mutant, including the ability to express robust responses to jasmonate and to accumulate indolic glucosinolates. Furthermore, the jaz10phyB double mutant showed a significantly increased resistance to the pathogenic fungus Botrytis cinerea compared with the phyB parental line. Our results demonstrate that, by inactivating JAZ10, it is possible to partially uncouple shade avoidance from defence suppression in Arabidopsis. These findings may provide clues to improve plant resistance to pathogens in crops that are planted at high density. © 2016 John Wiley & Sons Ltd.

Identification of the plants use as natural herbal shampoo in Manipur.

PubMed

Singh, S R; Phurailatpam, A K; Senjam, P

2014-01-01

A field survey was conducted in the year, 2011 - 12 in Imphal valley of Manipur, on the use of herbs as ingredient sources for the preparation of traditional natural herbal shampoo referred to as 'Chinghi', by Meitei community. Methodological field survey and personal interview of local people aged between 30-70 years of both sexes using standard questionnaires were carried out to collect information on the plants use in the herbal shampoo preparation. The survey revealed the therapeutic application of 35 plant species representing 28 genera and 18 families available in the Imphal valley. Tree species contributed immensely, yielding 38%, while herbs 32%, shrubs 27%, and climbing shrubs 3%, respectively being the record of the total number of plants used as ingredient in herbal shampoo preparation. These natural shampoos are used for a wide range of common hair care like anti-ageing of the hair, blackness, shininess and smoothness of the hair. It is prepared from young leaves and tender stalk of shoot of trees or shrubs, or whole plant of the herbs and fresh fruits boiled with local sticky rice water locally called 'Chinghi'. Fermented lime peel is also used as a herbal shampoo. The study shows details of their scientific, common, and local names, including their family, parts used, habit of the plants, and the benefit to the hair health as a whole.

Nonnative invasive plants: Maintaining biotic and soceioeconomic integrity along the urban-rural-natural gradient

Treesearch

Cynthia D. Huebner; David J. Nowak; Richard V. Pouyat; Allison R. Bodine

2012-01-01

In this chapter, we evaluate nonnative invasive plant species of the urban-rural-natural area gradient in order to reduce negative impacts of invasive plants on native species and ecosystems. This evaluation includes addressing (i) the concept of urban areas as the primary source of invasive plant species and characteristics of urban nonnative plants, including their...

Naturally seeded versus planted ponderosa pine seedlings in group-selection openings

Treesearch

Philip M. McDonald; Gary Fiddler; Martin Ritchie; Paula Anderson

2009-01-01

The purpose of this article was to determine whether natural regeneration or planted seedlings should be used in group-selection openings. The answer dependson the survival and growth rate of both types of seedlings, and that could depend on the size of the openings and the effect of trees on their edge. In thisside-by-side study, the natural pine seedlings originated...

Promotion of interferon-gamma production by natural killer cells via suppression of murine peritoneal macrophage prostaglandin E₂ production using intravenous anesthetic propofol.

PubMed

Inada, Takefumi; Kubo, Kozue; Shingu, Koh

2010-10-01

Propofol is an intravenous anesthetic, widely used for general anesthesia during surgery, which inevitably involves tissue trauma with inflammation. At sites of inflammation, prostanoids, especially prostaglandin E₂ (PGE₂), are abundant. This study addresses the effect of propofol on macrophage PGE₂ production. Using thioglycollate-elicited murine peritoneal macrophages, propofol (7.5-30 μM) suppressed lipopolysaccharide-induced PGE₂ production. The suppression was via the direct inhibition of cyclooxygenase (COX) enzyme activity and due neither to the downregulation of COX expression nor the inhibition of arachidonic acid release from plasma membranes. In macrophage:natural killer (NK) cell co-culture, propofol dramatically increased interferon-gamma (IFN-γ) production, and the actions of propofol were mimicked by a selective COX-2 inhibitor, NS-398, as well as the selective EP4 receptor antagonist L-161,982, suggesting a role of PGE₂ suppression in the upregulation of IFN-γ production. Furthermore, in purified NK cell culture, PGE₂ directly suppressed the production of IFN-γ by activated NK cells, which was reversed by selective inhibition of EP4 activity. Taken together, our results show that, in macrophage:NK cell co-culture, propofol, through the suppression of macrophage PGE₂ production, upregulates NK cell IFN-γ production by alleviating EP4 receptor-mediated suppression of IFN-γ production. Propofol may potentially exert considerable influence on inflammation and immunity by suppressing PGE₂ synthesis. Copyright © 2010 Elsevier B.V. All rights reserved.

Plant management in natural areas: balancing chemical, mechanical, and cultural control methods

Treesearch

Steven Manning; James Miller

2011-01-01

After determining the best course of action for control of an invasive plant population, it is important to understand the variety of methods available to the integrated pest management professional. A variety of methods are now widely used in managing invasive plants in natural areas, including chemical, mechanical, and cultural control methods. Once the preferred...

Plant extracts and natural compounds used against UVB-induced photoaging.

PubMed

Cavinato, Maria; Waltenberger, Birgit; Baraldo, Giorgia; Grade, Carla V C; Stuppner, Hermann; Jansen-Dürr, Pidder

2017-08-01

Skin is continuously exposed to a variety of environmental stresses, including ultraviolet (UV) radiation. UVB is an inherent component of sunlight that crosses the epidermis and reaches the upper dermis, leading to increased oxidative stress, activation of inflammatory response and accumulation of DNA damage among other effects. The increase in UVB radiation on earth due to the destruction of stratospheric ozone poses a major environmental threat to the skin, increasing the risk of damage with long-term consequences, such as photoaging and photocarcinogenesis. Extracts from plants and natural compounds have been historically used in traditional medicine in the form of teas and ointments but the effect of most of these compounds has yet to be verified. Regarding the increasing concern of the population with issues related to quality of life and appearance, the cosmetic market for anti-aging and photoprotective products based on natural compounds is continuously growing, and there is increasing requirement of expansion on research in this field. In this review we summarized the most current and relevant information concerning plant extracts and natural compounds that are able to protect or mitigate the deleterious effects caused by photoaging in different experimental models.

The hidden consequences of fire suppression

Treesearch

Carol Miller

2012-01-01

Wilderness managers need a way to quantify and monitor the effects of suppressing lightning-caused wildfires, which can alter natural fire regimes, vegetation, and habitat. Using computerized models of fire spread, weather, and fuels, it is now possible to quantify many of the hidden consequences of fire suppression. Case study watersheds in Yosemite and Sequoia-Kings...

Efficacy of Neoseiulus californicus and Phytoseiulus persimilis in suppression of Tetranychus urticae in young clementine plants.

PubMed

Abad-Moyano, Raquel; Pina, Tatiana; Pérez-Panadés, Jordi; Carbonell, Emilio A; Urbaneja, Alberto

2010-04-01

Tetranychus urticae is one of the most damaging tetranychid mites affecting clementine orchards in Spain, where natural control is insufficient. Furthermore, in clementine nurseries, tender foliage is highly susceptible to attack and natural enemies are almost always absent. Therefore, acaricides are often used indiscriminately. Alternative control measures are necessary, both in commercial orchards and clementine nurseries. In order to assess the efficacy of inoculative releases of N. californicus and P. persimilis to reduce T. urticae populations in young Spanish clementine plants, a semi-field experiment was conducted and repeated in three seasons (spring, summer and autumn). Phytoseiulus persimilis was highly effective in reducing both T. urticae infestations and the damage level inflicted on plants at both release rates evaluated (40 and 80 phytoseiids/plant) and all three periods considered. By contrast, N. californicus demonstrated low performance under certain conditions. The results of this study could be adapted and transferred to nurseries and young citrus plantations.

Improving management of nonnative invasive plants in wilderness and other natural areas

Treesearch

John M. Randall

2000-01-01

Nonnative invasive plants invade wilderness and other natural areas throughout North America and invasive organisms as a group are now considered the second worst threat to biodiversity, behind only habitat loss and fragmentation. In the past 10-20 years there have been upsurges in interest in the ecology of plant invasions among researchers and in concern about how to...

Genetic variation in plant volatile emission does not result in differential attraction of natural enemies in the field.

PubMed

Wason, Elizabeth L; Hunter, Mark D

2014-02-01

Volatile organic chemical (VOC) emission by plants may serve as an adaptive plant defense by attracting the natural enemies of herbivores. For plant VOC emission to evolve as an adaptive defense, plants must show genetic variability for the trait. To date, such variability has been investigated primarily in agricultural systems, yet relatively little is known about genetic variation in VOCs emitted by natural populations of native plants. Here, we investigate intraspecific variation in constitutive and herbivore-induced plant VOC emission using the native common milkweed plant (Asclepias syriaca) and its monarch caterpillar herbivore (Danaus plexippus) in complementary field and common garden greenhouse experiments. In addition, we used a common garden field experiment to gauge natural enemy attraction to milkweed VOCs induced by monarch damage. We found evidence of genetic variation in the total constitutive and induced concentrations of VOCs and the composition of VOC blends emitted by milkweed plants. However, all milkweed genotypes responded similarly to induction by monarchs in terms of their relative change in VOC concentration and blend. Natural enemies attacked decoy caterpillars more frequently on damaged than on undamaged milkweed, and natural enemy visitation was associated with higher total VOC concentrations and with VOC blend. Thus, we present evidence that induced VOCs emitted by milkweed may function as a defense against herbivores. However, plant genotypes were equally attractive to natural enemies. Although milkweed genotypes diverge phenotypically in their VOC concentrations and blends, they converge into similar phenotypes with regard to magnitude of induction and enemy attraction.

Sargassum as a Natural Solution to Enhance Dune Plant Growth

NASA Astrophysics Data System (ADS)

Williams, Amy; Feagin, Rusty

2010-11-01

Many beach management practices focus on creating an attractive environment for tourists, but can detrimentally affect long-term dune integrity. One such practice is mechanical beach raking in which the wrack line is removed from the beach front. In Texas, Sargassum fluitans and natans, types of brown alga, are the main components of wrack and may provide a subsidy to the ecosystem. In this study, we used greenhouse studies to test the hypothesis that the addition of sargassum can increase soil nutrients and produce increased growth in dune plants. We also conducted an analysis of the nutrients in the sargassum to determine the mechanisms responsible for any growth enhancement. Panicum amarum showed significant enhancement of growth with the addition of sargassum, and while Helianthus debilis, Ipomoea stolonifera, Sporobolus virginicus, and Uniola paniculata responded slightly differently to the specific treatments, none were impaired by the addition of sargassum. In general, plants seemed to respond well to unwashed sargassum and multiple additions of sargassum, indicating that plants may have adapted to capitalize on the subsidy in its natural state directly from the ocean. For coastal managers, the use of sargassum as a fertilizer could be a positive, natural, and efficient method of dealing with the accumulation of wrack on the beach.

Active Suppression of Early Immune Response in Tobacco by the Human Pathogen Salmonella Typhimurium

PubMed Central

Shirron, Natali; Yaron, Sima

2011-01-01

The persistence of enteric pathogens on plants has been studied extensively, mainly due to the potential hazard of human pathogens such as Salmonella enterica being able to invade and survive in/on plants. Factors involved in the interactions between enteric bacteria and plants have been identified and consequently it was hypothesized that plants may be vectors or alternative hosts for enteric pathogens. To survive, endophytic bacteria have to escape the plant immune systems, which function at different levels through the plant-bacteria interactions. To understand how S. enterica survives endophyticaly we conducted a detailed analysis on its ability to elicit or evade the plant immune response. The models of this study were Nicotiana tabacum plants and cells suspension exposed to S. enterica serovar Typhimurium. The plant immune response was analyzed by looking at tissue damage and by testing oxidative burst and pH changes. It was found that S. Typhimurium did not promote disease symptoms in the contaminated plants. Live S. Typhimurium did not trigger the production of an oxidative burst and pH changes by the plant cells, while heat killed or chloramphenicol treated S. Typhimurium and purified LPS of Salmonella were significant elicitors, indicating that S. Typhimurium actively suppress the plant response. By looking at the plant response to mutants defective in virulence factors we showed that the suppression depends on secreted factors. Deletion of invA reduced the ability of S. Typhimurium to suppress oxidative burst and pH changes, indicating that a functional SPI1 TTSS is required for the suppression. This study demonstrates that plant colonization by S. Typhimurium is indeed an active process. S. Typhimurium utilizes adaptive strategies of altering innate plant perception systems to improve its fitness in the plant habitat. All together these results suggest a complex mechanism for perception of S. Typhimurium by plants. PMID:21541320

Phosphite, an analog of phosphate, suppresses the coordinated expression of genes under phosphate starvation.

PubMed

Varadarajan, Deepa K; Karthikeyan, Athikkattuvalasu S; Matilda, Paino Durzo; Raghothama, Kashchandra G

2002-07-01

Phosphate (Pi) and its analog phosphite (Phi) are acquired by plants via Pi transporters. Although the uptake and mobility of Phi and Pi are similar, there is no evidence suggesting that plants can utilize Phi as a sole source of phosphorus. Phi is also known to interfere with many of the Pi starvation responses in plants and yeast (Saccharomyces cerevisiae). In this study, effects of Phi on plant growth and coordinated expression of genes induced by Pi starvation were analyzed. Phi suppressed many of the Pi starvation responses that are commonly observed in plants. Enhanced root growth and root to shoot ratio, a hallmark of Pi stress response, was strongly inhibited by Phi. The negative effects of Phi were not obvious in plants supplemented with Pi. The expression of Pi starvation-induced genes such as LePT1, LePT2, AtPT1, and AtPT2 (high-affinity Pi transporters); LePS2 (a novel acid phosphatase); LePS3 and TPSI1 (novel genes); and PAP1 (purple acid phosphatase) was suppressed by Phi in plants and cell cultures. Expression of luciferase reporter gene driven by the Pi starvation-induced AtPT2 promoter was also suppressed by Phi. These analyses showed that suppression of Pi starvation-induced genes is an early response to addition of Phi. These data also provide evidence that Phi interferes with gene expression at the level of transcription. Synchronized suppression of multiple Pi starvation-induced genes by Phi points to its action on the early molecular events, probably signal transduction, in Pi starvation response.

Natural metabolites for parasitic weed management.

PubMed

Vurro, Maurizio; Boari, Angela; Evidente, Antonio; Andolfi, Anna; Zermane, Nadjia

2009-05-01

Compounds of natural origin, such as phytotoxins produced by fungi or natural amino acids, could be used in parasitic weed management strategies by interfering with the early growth stages of the parasites. These metabolites could inhibit seed germination or germ tube elongation, so preventing attachment to the host plant, or, conversely, stimulate seed germination in the absence of the host, contributing to a reduction in the parasite seed bank. Some of the fungal metabolites assayed were very active even at very low concentrations, such as some macrocyclic trichothecenes, which at 0.1 microM strongly suppressed the germination of Orobanche ramosa L. seeds. Interesting results were also obtained with some novel toxins, such as phyllostictine A, highly active in reducing germ tube elongation and seed germination both of O. ramosa and of Cuscuta campestris Yuncker. Among the amino acids tested, methionine and arginine were particularly interesting, as they were able to suppress seed germination at concentrations lower than 1 mM. Some of the fungal metabolites tested were also able to stimulate the germination of O. ramosa seeds. The major findings in this research field are described and discussed.

Legacy effects of anaerobic soil disinfestation on soil bacterial community composition and production of pathogen-suppressing volatiles

PubMed Central

van Agtmaal, Maaike; van Os, Gera J.; Hol, W.H. Gera; Hundscheid, Maria P.J.; Runia, Willemien T.; Hordijk, Cornelis A.; de Boer, Wietse

2015-01-01

There is increasing evidence that microbial volatiles (VOCs) play an important role in natural suppression of soil-borne diseases, but little is known on the factors that influence production of suppressing VOCs. In the current study we examined whether a stress-induced change in soil microbial community composition would affect the production by soils of VOCs suppressing the plant-pathogenic oomycete Pythium. Using pyrosequencing of 16S ribosomal gene fragments we compared the composition of bacterial communities in sandy soils that had been exposed to anaerobic disinfestation (AD), a treatment used to kill harmful soil organisms, with the composition in untreated soils. Three months after the AD treatment had been finished, there was still a clear legacy effect of the former anaerobic stress on bacterial community composition with a strong increase in relative abundance of the phylum Bacteroidetes and a significant decrease of the phyla Acidobacteria, Planctomycetes, Nitrospirae, Chloroflexi, and Chlorobi. This change in bacterial community composition coincided with loss of production of Pythium suppressing soil volatiles (VOCs) and of suppression of Pythium impacts on Hyacinth root development. One year later, the composition of the bacterial community in the AD soils was reflecting that of the untreated soils. In addition, both production of Pythium-suppressing VOCs and suppression of Pythium in Hyacinth bioassays had returned to the levels of the untreated soil. GC/MS analysis identified several VOCs, among which compounds known to be antifungal, that were produced in the untreated soils but not in the AD soils. These compounds were again produced 15 months after the AD treatment. Our data indicate that soils exposed to a drastic stress can temporarily lose pathogen suppressive characteristics and that both loss and return of these suppressive characteristics coincides with shifts in the soil bacterial community composition. Our data are supporting the

Productivity as related to diversity and age in planted versus natural forests

Treesearch

Qinfeng Guo; Hai Ren

2014-01-01

Little is known about the performance of plantations relative to natural forests of the same climate zone and age. China has more plantations than any other country as a consequence of massive afforestation efforts.We use data from China to comparatively examine tree biomass and productivity of planted and natural stands in relation to climate zone, latitude, elevation...

Epigenetic Variation in Mangrove Plants Occurring in Contrasting Natural Environment

PubMed Central

Lira-Medeiros, Catarina Fonseca; Parisod, Christian; Fernandes, Ricardo Avancini; Mata, Camila Souza; Cardoso, Monica Aires; Ferreira, Paulo Cavalcanti Gomes

2010-01-01

Background Epigenetic modifications, such as cytosine methylation, are inherited in plant species and may occur in response to biotic or abiotic stress, affecting gene expression without changing genome sequence. Laguncularia racemosa, a mangrove species, occurs in naturally contrasting habitats where it is subjected daily to salinity and nutrient variations leading to morphological differences. This work aims at unraveling how CpG-methylation variation is distributed among individuals from two nearby habitats, at a riverside (RS) or near a salt marsh (SM), with different environmental pressures and how this variation is correlated with the observed morphological variation. Principal Findings Significant differences were observed in morphological traits such as tree height, tree diameter, leaf width and leaf area between plants from RS and SM locations, resulting in smaller plants and smaller leaf size in SM plants. Methyl-Sensitive Amplified Polymorphism (MSAP) was used to assess genetic and epigenetic (CpG-methylation) variation in L. racemosa genomes from these populations. SM plants were hypomethylated (14.6% of loci had methylated samples) in comparison to RS (32.1% of loci had methylated samples). Within-population diversity was significantly greater for epigenetic than genetic data in both locations, but SM also had less epigenetic diversity than RS. Frequency-based (GST) and multivariate (βST) methods that estimate population structure showed significantly greater differentiation among locations for epigenetic than genetic data. Co-Inertia analysis, exploring jointly the genetic and epigenetic data, showed that individuals with similar genetic profiles presented divergent epigenetic profiles that were characteristic of the population in a particular environment, suggesting that CpG-methylation changes may be associated with environmental heterogeneity. Conclusions In spite of significant morphological dissimilarities, individuals of L. racemosa from salt

Isolation, identification and expression analysis of salt-induced genes in Suaeda maritima, a natural halophyte, using PCR-based suppression subtractive hybridization

PubMed Central

Sahu, Binod B; Shaw, Birendra P

2009-01-01

Background Despite wealth of information generated on salt tolerance mechanism, its basics still remain elusive. Thus, there is a need of continued effort to understand the salt tolerance mechanism using suitable biotechnological techniques and test plants (species) to enable development of salt tolerant cultivars of interest. Therefore, the present study was undertaken to generate information on salt stress responsive genes in a natural halophyte, Suaeda maritima, using PCR-based suppression subtractive hybridization (PCR-SSH) technique. Results Forward and reverse SSH cDNA libraries were constructed after exposing the young plants to 425 mM NaCl for 24 h. From the forward SSH cDNA library, 429 high quality ESTs were obtained. BLASTX search and TIGR assembler programme revealed overexpression of 167 unigenes comprising 89 singletons and 78 contigs with ESTs redundancy of 81.8%. Among the unigenes, 32.5% were found to be of special interest, indicating novel function of these genes with regard to salt tolerance. Literature search for the known unigenes revealed that only 17 of them were salt-inducible. A comparative analysis of the existing SSH cDNA libraries for NaCl stress in plants showed that only a few overexpressing unigenes were common in them. Moreover, the present study also showed increased expression of phosphoethanolamine N-methyltransferase gene, indicating the possible accumulation of a much studied osmoticum, glycinebetaine, in halophyte under salt stress. Functional categorization of the proteins as per the Munich database in general revealed that salt tolerance could be largely determined by the proteins involved in transcription, signal transduction, protein activity regulation and cell differentiation and organogenesis. Conclusion The study provided a clear indication of possible vital role of glycinebetaine in the salt tolerance process in S. maritima. However, the salt-induced expression of a large number of genes involved in a wide range of

Introduction of a Chimeric Chalcone Synthase Gene into Petunia Results in Reversible Co-Suppression of Homologous Genes in trans.

PubMed Central

Napoli, C; Lemieux, C; Jorgensen, R

1990-01-01

We attempted to overexpress chalcone synthase (CHS) in pigmented petunia petals by introducing a chimeric petunia CHS gene. Unexpectedly, the introduced gene created a block in anthocyanin biosynthesis. Forty-two percent of plants with the introduced CHS gene produced totally white flowers and/or patterned flowers with white or pale nonclonal sectors on a wild-type pigmented background; none of hundreds of transgenic control plants exhibited such phenotypes. Progeny testing of one plant demonstrated that the novel color phenotype co-segregated with the introduced CHS gene; progeny without this gene were phenotypically wild type. The somatic and germinal stability of the novel color patterns was variable. RNase protection analysis of petal RNAs isolated from white flowers showed that, although the developmental timing of mRNA expression of the endogenous CHS gene was not altered, the level of the mRNA produced by this gene was reduced 50-fold from wild-type levels. Somatic reversion of plants with white flowers to phenotypically parental violet flowers was associated with a coordinate rise in the steady-state levels of the mRNAs produced by both the endogenous and the introduced CHS genes. Thus, in the altered white flowers, the expression of both genes was coordinately suppressed, indicating that expression of the introduced CHS gene was not alone sufficient for suppression of endogenous CHS transcript levels. The mechanism responsible for the reversible co-suppression of homologous genes in trans is unclear, but the erratic and reversible nature of this phenomenon suggests the possible involvement of methylation. PMID:12354959

Investigation of Natural Radioactivity in a Monazite Processing Plant in Japan.

PubMed

Iwaoka, Kazuki; Yajima, Kazuaki; Suzuki, Toshikazu; Yonehara, Hidenori; Hosoda, Masahiro; Tokonami, Shinji; Kanda, Reiko

2017-09-01

Monazite is a naturally occurring radioactive material that is processed for use in a variety of domestic applications. At present, there is little information available on potential radiation doses experienced by people working with monazite. The ambient dose rate and activity concentration of natural radionuclides in raw materials, products, and dust in work sites as well as the Rn and Rn concentrations in work sites were measured in a monazite processing plant in Japan. Dose estimations for plant workers were also conducted. The activity concentration of the U series in raw materials and products for the monazite processing plant was found to be higher than the relevant values described in the International Atomic Energy Agency Safety Standards. The ambient dose rates in the raw material yard were higher than those in other work sites. Moreover, the activity concentrations of dust in the milling site were higher than those in other work sites. The Rn concentrations in all work sites were almost the same as those in regular indoor environments in Japan. The Rn concentrations in all work sites were much higher than those in regular indoor environments in Japan. The maximum value of the effective dose for workers was 0.62 mSv y, which is lower than the reference level range (1-20 mSv y) for abnormally high levels of natural background radiation published in the International Commission of Radiological Protection Publication 103.

Beyond theories of plant invasions: Lessons from natural landscapes

USGS Publications Warehouse

Stohlgren, Thomas J.

2002-01-01

There are a growing number of contrasting theories about plant invasions, but most are only weakly supported by small-scale field experiments, observational studies, and mathematical models. Among the most contentious theories is that species-rich habitats should be less vulnerable to plant invasion than species-poor sites, stemming from earlier theories that competition is a major force in structuring plant communities. Early ecologists such as Charles Darwin (1859) and Charles Elton (1958) suggested that a lack of intense interspecific competition on islands made these low-diversity habitats vulnerable to invasion. Small-scale field experiments have supported and contradicted this theory, as have various mathematical models. In contrast, many large-scale observational studies and detailed vegetation surveys in continental areas often report that species-rich areas are more heavily invaded than species-poor areas, but there are exceptions here as well. In this article, I show how these seemingly contrasting patterns converge once appropriate spatial and temporal scales are considered in complex natural environments. I suggest ways in which small-scale experiments, mathematical models, and large- scale observational studies can be improved and better integrated to advance a theoretically based understanding of plant invasions.

Disease Suppressive Soils: New Insights from the Soil Microbiome.

PubMed

Schlatter, Daniel; Kinkel, Linda; Thomashow, Linda; Weller, David; Paulitz, Timothy

2017-11-01

Soils suppressive to soilborne pathogens have been identified worldwide for almost 60 years and attributed mainly to suppressive or antagonistic microorganisms. Rather than identifying, testing and applying potential biocontrol agents in an inundative fashion, research into suppressive soils has attempted to understand how indigenous microbiomes can reduce disease, even in the presence of the pathogen, susceptible host, and favorable environment. Recent advances in next-generation sequencing of microbiomes have provided new tools to reexamine and further characterize the nature of these soils. Two general types of suppression have been described: specific and general suppression, and theories have been developed around these two models. In this review, we will present three examples of currently-studied model systems with features representative of specific and general suppressiveness: suppression to take-all (Gaeumannomyces graminis var. tritici), Rhizoctonia bare patch of wheat (Rhizoctonia solani AG-8), and Streptomyces. To compare and contrast the two models of general versus specific suppression, we propose a number of hypotheses about the nature and ecology of microbial populations and communities of suppressive soils. We outline the potential and limitations of new molecular techniques that can provide novel ways of testing these hypotheses. Finally, we consider how this greater understanding of the phytobiome can facilitate sustainable disease management in agriculture by harnessing the potential of indigenous soil microbes.

Natural genetic variation for morphological and molecular determinants of plant growth and yield.

PubMed

Nunes-Nesi, Adriano; Nascimento, Vitor de Laia; de Oliveira Silva, Franklin Magnum; Zsögön, Agustin; Araújo, Wagner L; Sulpice, Ronan

2016-05-01

The rates of increase in yield of the main commercial crops have been steadily falling in many areas worldwide. This generates concerns because there is a growing demand for plant biomass due to the increasing population. Plant yield should thus be improved in the context of climate change and decreasing natural resources. It is a major challenge which could be tackled by improving and/or altering light-use efficiency, CO2 uptake and fixation, primary metabolism, plant architecture and leaf morphology, and developmental plant processes. In this review, we discuss some of the traits which could lead to yield increase, with a focus on how natural genetic variation could be harnessed. Moreover, we provide insights for advancing our understanding of the molecular aspects governing plant growth and yield, and propose future avenues for improvement of crop yield. We also suggest that knowledge accumulated over the last decade in the field of molecular physiology should be integrated into new ideotypes. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Engineering of new-to-nature halogenated indigo precursors in plants.

PubMed

Fräbel, Sabine; Wagner, Bastian; Krischke, Markus; Schmidts, Volker; Thiele, Christina M; Staniek, Agata; Warzecha, Heribert

2018-03-01

Plants are versatile chemists producing a tremendous variety of specialized compounds. Here, we describe the engineering of entirely novel metabolic pathways in planta enabling generation of halogenated indigo precursors as non-natural plant products. Indican (indolyl-β-D-glucopyranoside) is a secondary metabolite characteristic of a number of dyers plants. Its deglucosylation and subsequent oxidative dimerization leads to the blue dye, indigo. Halogenated indican derivatives are commonly used as detection reagents in histochemical and molecular biology applications; their production, however, relies largely on chemical synthesis. To attain the de novo biosynthesis in a plant-based system devoid of indican, we employed a sequence of enzymes from diverse sources, including three microbial tryptophan halogenases substituting the amino acid at either C5, C6, or C7 of the indole moiety. Subsequent processing of the halotryptophan by bacterial tryptophanase TnaA in concert with a mutant of the human cytochrome P450 monooxygenase 2A6 and glycosylation of the resulting indoxyl derivatives by an endogenous tobacco glucosyltransferase yielded corresponding haloindican variants in transiently transformed Nicotiana benthamiana plants. Accumulation levels were highest when the 5-halogenase PyrH was utilized, reaching 0.93 ± 0.089 mg/g dry weight of 5-chloroindican. The identity of the latter was unambiguously confirmed by NMR analysis. Moreover, our combinatorial approach, facilitated by the modular assembly capabilities of the GoldenBraid cloning system and inspired by the unique compartmentation of plant cells, afforded testing a number of alternative subcellular localizations for pathway design. In consequence, chloroplasts were validated as functional biosynthetic venues for haloindican, with the requisite reducing augmentation of the halogenases as well as the cytochrome P450 monooxygenase fulfilled by catalytic systems native to the organelle. Thus, our study

Loose Plant Architecture1 (LPA1) determines lamina joint bending by suppressing auxin signalling that interacts with C-22-hydroxylated and 6-deoxo brassinosteroids in rice

PubMed Central

Liu, Jing Miao; Park, Soon Ju; Huang, Jin; Lee, Eun Jin; Xuan, Yuan Hu; Je, Byoung Il; Kumar, Vikranth; Priatama, Ryza A.; Raj K, Vimal; Kim, Sung Hoon; Min, Myung Ki; Cho, Jun Hyeon; Kim, Tae Ho; Chandran, Anil Kumar Nalini; Jung, Ki Hong; Takatsuto, Suguru; Fujioka, Shozo; Han, Chang-deok

2016-01-01

Lamina inclination is a key agronomical character that determines plant architecture and is sensitive to auxin and brassinosteroids (BRs). Loose Plant Architecture1 (LPA1) in rice (Oryza sativa) and its Arabidopsis homologues (SGR5/AtIDD15) have been reported to control plant architecture and auxin homeostasis. This study explores the role of LPA1 in determining lamina inclination in rice. LPA1 acts as a positive regulator to suppress lamina bending. Genetic and biochemical data indicate that LPA1 suppresses the auxin signalling that interacts with C-22-hydroxylated and 6-deoxo BRs, which regulates lamina inclination independently of OsBRI1. Mutant lpa1 plants are hypersensitive to indole-3-acetic acid (IAA) during the lamina inclination response, which is suppressed by the brassinazole (Brz) inhibitor of C-22 hydroxylase involved in BR synthesis. A strong synergic effect is detected between lpa1 and d2 (the defective mutant for catalysis of C-23-hydroxylated BRs) during IAA-mediated lamina inclination. No significant interaction between LPA1 and OsBRI1 was identified. The lpa1 mutant is sensitive to C-22-hydroxylated and 6-deoxo BRs in the d61-1 (rice BRI1 mutant) background. We present evidence verifying that two independent pathways function via either BRs or BRI1 to determine IAA-mediated lamina inclination in rice. RNA sequencing analysis and qRT-PCR indicate that LPA1 influences the expression of three OsPIN genes (OsPIN1a, OsPIN1c and OsPIN3a), which suggests that auxin flux might be an important factor in LPA1-mediated lamina inclination in rice. PMID:26826218

Medicinal plants and natural products in amelioration of arsenic toxicity: a short review.

PubMed

Bhattacharya, Sanjib

2017-12-01

Chronic arsenic toxicity (arsenicosis) is considered a serious public health menace worldwide, as there is no specific, safe, and efficacious therapeutic management of arsenicosis. To collate the studies on medicinal plants and natural products with arsenic toxicity ameliorative effect, active pre-clinically and/or clinically. Literature survey was carried out by using Google, Scholar Google and Pub-Med. Only the scientific journal articles found on the internet for last two decades were considered. Minerals and semi-synthetic or synthetic analogs of natural products were excluded. Literature study revealed that 34 medicinal plants and 14 natural products exhibited significant protection from arsenic toxicity, mostly in preclinical trials and a few in clinical studies. This research could lead to development of a potentially useful agent in clinical management of arsenicosis in humans.

Suppression of Damping-Off Disease in Host Plants by the Rhizoplane Bacterium Lysobacter sp. Strain SB-K88 Is Linked to Plant Colonization and Antibiosis against Soilborne Peronosporomycetes

PubMed Central

Islam, Md. Tofazzal; Hashidoko, Yasuyuki; Deora, Abhinandan; Ito, Toshiaki; Tahara, Satoshi

2005-01-01

We previously demonstrated that xanthobaccin A from the rhizoplane bacterium Lysobacter sp. strain SB-K88 suppresses damping-off disease caused by Pythium sp. in sugar beet. In this study we focused on modes of Lysobacter sp. strain SB-K88 root colonization and antibiosis of the bacterium against Aphanomyces cochlioides, a pathogen of damping-off disease. Scanning electron microscopic analysis of 2-week-old sugar beet seedlings from seeds previously inoculated with SB-K88 revealed dense colonization on the root surfaces and a characteristic perpendicular pattern of Lysobacter colonization possibly generated via development of polar, brush-like fimbriae. In colonized regions a semitransparent film apparently enveloping the root and microcolonies were observed on the root surface. This Lysobacter strain also efficiently colonized the roots of several plants, including spinach, tomato, Arabidopsis thaliana, and Amaranthus gangeticus. Plants grown from both sugar beet and spinach seeds that were previously treated with Lysobacter sp. strain SB-K88 displayed significant resistance to the damping-off disease triggered by A. cochlioides. Interestingly, zoospores of A. cochlioides became immotile within 1 min after exposure to a SB-K88 cell suspension, a cell-free supernatant of SB-K88, or pure xanthobaccin A (MIC, 0.01 μg/ml). In all cases, lysis followed within 30 min in the presence of the inhibiting factor(s). Our data indicate that Lysobacter sp. strain SB-K88 has a direct inhibitory effect on A. cochlioides, suppressing damping-off disease. Furthermore, this inhibitory effect of Lysobacter sp. strain SB-K88 is likely due to a combination of antibiosis and characteristic biofilm formation at the rhizoplane of the host plant. PMID:16000790

Antisense suppression of violaxanthin de-epoxidase in tobacco does not affect plant performance in controlled growth conditions.

PubMed

Chang, S H; Bugos, R C; Sun, W H; Yamamoto, H Y

2000-01-01

Violaxanthin de-epoxidase (VDE) catalyzes the de-epoxidation of violaxanthin to antheraxanthin and zeaxanthin in the xanthophyll cycle. Tobacco was transformed with an antisense VDE construct under control of the cauliflower mosaic virus 35S promoter to determine the effect of reduced levels of VDE on plant growth. Screening of 40 independent transformants revealed 18 antisense lines with reduced levels of VDE activity with two in particular (TAS32 and TAS39) having greater than 95% reduction in VDE activity. Northern analysis demonstrated that these transformants had greatly suppressed levels of VDE mRNA. De-epoxidation of violaxanthin was inhibited to such an extent that no zeaxanthin and only very low levels of antheraxanthin could be detected after exposure of leaves to high light (2000 mumol m(-2) s(-1) for 20 min) with no observable effect on levels of other carotenoids and chlorophyll. Non-photochemical quenching was greatly reduced in the antisense VDE tobacco, demonstrating that a significant level of the non-photochemical quenching in tobacco requires de-epoxidation of violaxanthin. Although the antisense plants demonstrated a greatly impaired de-epoxidation of violaxanthin, no effect on plant growth or photosynthetic rate was found when plants were grown at a photon flux density of 500 or 1000 mumol m(-2) s(-1) under controlled growth conditions as compared to wild-type tobacco.

The Sinorhizobium (Ensifer) fredii HH103 Type 3 Secretion System Suppresses Early Defense Responses to Effectively Nodulate Soybean.

PubMed

Jiménez-Guerrero, Irene; Pérez-Montaño, Francisco; Monreal, José Antonio; Preston, Gail M; Fones, Helen; Vioque, Blanca; Ollero, Francisco Javier; López-Baena, Francisco Javier

2015-07-01

Plants that interact with pathogenic bacteria in their natural environments have developed barriers to block or contain the infection. Phytopathogenic bacteria have evolved mechanisms to subvert these defenses and promote infection. Thus, the type 3 secretion system (T3SS) delivers bacterial effectors directly into the plant cells to alter host signaling and suppress defenses, providing an appropriate environment for bacterial multiplication. Some rhizobial strains possess a symbiotic T3SS that seems to be involved in the suppression of host defenses to promote nodulation and determine the host range. In this work, we show that the inactivation of the Sinorhizobium (Ensifer) fredii HH103 T3SS negatively affects soybean nodulation in the early stages of the symbiotic process, which is associated with a reduction of the expression of early nodulation genes. This symbiotic phenotype could be the consequence of the bacterial triggering of soybean defense responses associated with the production of salicylic acid (SA) and the impairment of the T3SS mutant to suppress these responses. Interestingly, the early induction of the transcription of GmMPK4, which negatively regulates SA accumulation and defense responses in soybean via WRKY33, could be associated with the differential defense responses induced by the parental and the T3SS mutant strain.

Natural gums of plant origin as edible coatings for food industry applications.

PubMed

Saha, Anuradha; Tyagi, Shvetambri; Gupta, Rajinder K; Tyagi, Yogesh K

2017-12-01

Natural plant-based gums and their derivatives are widely utilized in food industries, however, their applications as edible coatings to extend fresh fruits and vegetable shelf-life has been explored recently. These natural polymeric polysaccharides have many advantages as compared to synthetic polymers, because they are biodegradable, nontoxic, economical and easily available in the environment. Natural gums can also be semi synthetically modified to produce derivatives, which can easily compete with the synthetic preservatives available on the food market. In this review, the recent developments in the use of natural gums and their derivatives as edible coatings have been explored and discussed.

Water-soluble metal nanoparticles stabilized by plant polyphenols for improving the catalytic properties in oxidation of alcohols

NASA Astrophysics Data System (ADS)

Mao, H.; Liao, Y.; Ma, J.; Zhao, S. L.; Huo, F. W.

2015-12-01

Plant polyphenols extracted from plants are one of the most abundant biomasses in nature, which are typical water soluble natural polymers. Herein, we reported a facile approach for the synthesis of platinum nanoparticle (PtNP) aqueous colloid by utilizing black wattle tannin (BWT, a typical plant polyphenol) as amphiphilic stabilizer. The phenolic hydroxyls of BWT provide the PtNPs with enough hydrophilicity, and their reduction ability could protect the PtNPs from deactivation caused by oxygen atmosphere. Additionally, the hydrophilic nature of BWT could efficiently promote the oxidation of alcohols in water, meanwhile, the hydrophobic and rigid backbones of plant polyphenols are able to suppress the PtNPs from aggregating, thus ensuring the high dispersion of the PtNPs during reactions. Under mild aerobic conditions, the as-prepared BWT-Pt colloid catalyst exhibited high activity in a series of biphasic oxidation of aromatic alcohols and aliphatic alcohols. As for the cycling stability, the BWT-Pt catalyst showed no obvious decrease during the 7 cycles, revealing superior cycling stability as compared with the counterparts using PVP or PEG as the stabilizer.Plant polyphenols extracted from plants are one of the most abundant biomasses in nature, which are typical water soluble natural polymers. Herein, we reported a facile approach for the synthesis of platinum nanoparticle (PtNP) aqueous colloid by utilizing black wattle tannin (BWT, a typical plant polyphenol) as amphiphilic stabilizer. The phenolic hydroxyls of BWT provide the PtNPs with enough hydrophilicity, and their reduction ability could protect the PtNPs from deactivation caused by oxygen atmosphere. Additionally, the hydrophilic nature of BWT could efficiently promote the oxidation of alcohols in water, meanwhile, the hydrophobic and rigid backbones of plant polyphenols are able to suppress the PtNPs from aggregating, thus ensuring the high dispersion of the PtNPs during reactions. Under mild aerobic

Finding and defining the natural automata acting in living plants: Toward the synthetic biology for robotics and informatics in vivo.

PubMed

Kawano, Tomonori; Bouteau, François; Mancuso, Stefano

2012-11-01

The automata theory is the mathematical study of abstract machines commonly studied in the theoretical computer science and highly interdisciplinary fields that combine the natural sciences and the theoretical computer science. In the present review article, as the chemical and biological basis for natural computing or informatics, some plants, plant cells or plant-derived molecules involved in signaling are listed and classified as natural sequential machines (namely, the Mealy machines or Moore machines) or finite state automata. By defining the actions (states and transition functions) of these natural automata, the similarity between the computational data processing and plant decision-making processes became obvious. Finally, their putative roles as the parts for plant-based computing or robotic systems are discussed.

Suppression of glycolate oxidase causes glyoxylate accumulation that inhibits photosynthesis through deactivating Rubisco in rice.

PubMed

Lu, Yusheng; Li, Yong; Yang, Qiaosong; Zhang, Zhisheng; Chen, Yan; Zhang, Sheng; Peng, Xin-Xiang

2014-03-01

Glycolate oxidase (GLO) is a key enzyme for photorespiration in plants. Previous studies have demonstrated that suppression of GLO causes photosynthetic inhibition, and the accumulated glycolate with the deactivated Rubisco is likely involved in the regulation. Using isolated Rubisco and chloroplasts, it has been found that only glyoxylate can effectively inactivate Rubisco and meanwhile inhibit photosynthesis, but little in vivo evidence has been acquired and reported. In this study, we have generated the transgenic rice (Oryza sativa) plants with GLO being constitutively silenced, and conducted the physiological and biochemical analyses on these plants to explore the regulatory mechanism. When GLO was downregulated, the net photosynthetic rate (Pn) was reduced and the plant growth was correspondingly stunted. Surprisingly, glyoxylate, as a product of the GLO catalysis, was accumulated in response to the GLO suppression, like its substrate glycolate. Furthermore, the glyoxylate content was found to be inversely proportional to the Pn while the Pn is directly proportional to the Rubisco activation state in the GLO-suppressed plants. A mathematical fitting equation using least square method also demonstrated that the Rubisco activation state was inversely proportional to the glyoxylate content. Despite that the further analyses we have conducted failed to reveal how glyoxylate was accumulated in response to the GLO suppression, the current results do strongly suggest that there may exist an unidentified, alternative pathway to produce glyoxylate, and that the accumulated glyoxylate inhibits photosynthesis by deactivating Rubisco, and causes the photorespiratory phenotype in the GLO-suppressed rice plants. © 2013 Scandinavian Plant Physiology Society.

Compost made of organic wastes suppresses fusariosis

NASA Astrophysics Data System (ADS)

Kuryntseva, Polina; Galitskaya, Polina; Biktasheva, Liliya; Selivanovkaya, Svetlana

2017-04-01

Fungal plant diseases cause dramatic yield losses worldwide. Usually, pesticides are used for soil sanitation, and it results in practically pest-free soils, although pesticides cause a biological vacuum, which present many horticultural disadvantages. Suppressive composts, which possess both fertilizing properties for plants and inhibiting properties for plant pathogens, represent an effective and environmentally friendly alternative to conventional pesticides. In this study, composts obtained from agricultural organic wastes were applied to suppress Fusarium oxysporum of tomato plants in model experiments. Composts were made of mixtures of the widespread organic wastes sampled in Tatarstan (Russia): straw (SW), corn wastes (CW), chicken manure (ChM), cattle manure (CM) and swine manure (SM). 11 two- and three-component mixtures were prepared to obtain the optimal carbon-nitrogen, moisture and pH balances, and composted for 210 days. It was found that the thermophilic phase of composting in all the mixtures lasted from 2 to 35 days, and was characterized by significant fluctuations in temperature, i.e. from 27°C to 59°C. In the initial mixtures, the dissolved organic carbon (DOC) content was between 10 and 62 mg kg-1; it fell significantly on day 13, and then continuously decreased up to day 102, and subsequently remained low. For all the mixtures, maximal respiration activity was observed in the beginning of composting (231.9 mg CO2-C g-1 day-1). After 23 days, this parameter decreased significantly, and fluctuations subsided. The phytotoxicity of the initial compost mixtures varied from 18% (SW+SM) to 100% (CW+ChM+SM, CW+ChM); however, the trends in the dynamics were similar. After 120 days of composting, 5 of 11 samples were not phytotoxic. After 120 days of composting, each mixture was divided into two parts; one was inoculated with a biopreparation consisting of four microbial strains (Trichoderma asperellum, Pseudomonas putida, Pseudomonas fluorescens and

Quantifying the consequences of fire suppression in two California national parks

Treesearch

Carol Miller; Brett Davis

2009-01-01

Excluding fire can have untold ecological effects. Decades of fire suppression in national parks and other protected areas have altered natural fire regimes, vegetation, and wildlife habitat (Chang 1996; Keane et al. 2002). Management actions to suppress lightning-ignited wildfires removes one of the most important natural processes from fire-dependent ecosystems, and...

Biological and Chemical Aspects of Natural Biflavonoids from Plants: A Brief Review.

PubMed

Gontijo, Vanessa Silva; Dos Santos, Marcelo Henrique; Viegas, Claudio

2017-01-01

Biflavonoids belong to a subclass of the plant flavonoids family and are limited to several species in the plant kingdom. In the literature, biflavonoids are extensively reported for their pharmacological properties including anti-inflammatory, antioxidant, inhibitory activity against phospholipase A2 (PLA2) and antiprotozoal activity. These activities have been discovered from the small number of biflavonoid structures that have been investigated, although the natural biflavonoids library is likely to be large. In addition, many medicinal properties and traditional use of plants are attributed to the presence of bioflavonoids among their secondary metabolites. Structurally, biflavonoids are polyphenol compounds comprising of two identical or non-identical flavonflavonoid units joined in a symmetrical or unsymmetrical manner through an alkyl or an alkoxy-based linker of varying length. Due to their chemical and biological importance, several bioprospective phytochemical studies and chemical approaches using coupling and molecular rearrangement strategies have been developed to identify and synthesize new bioactive biflavonoids. In this brief review, we present some basic structural aspects for classification and nomenclature of bioflavonoids and a compilation of the literature data published in the last 7 years, concerning the discovery of new natural biflavonoids of plant origin and their pharmacological and biological properties. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

The mechanism for weed suppression by a forage radish cover crop

USDA-ARS?s Scientific Manuscript database

In the Mid-Atlantic region, forage radish (Raphanus sativus L. var. longipinnatus) winter cover crops planted prior to 1 September suppress winter annual weeds from fall until early April. Little is known about the mechanism of this weed suppression. Published research reports suggest that allelopat...

Disease Suppressive Soils: New Insights from the Soil Microbiome

USDA-ARS?s Scientific Manuscript database

In this review, we will present three currently-studied model systems with features representative of specific and general suppressiveness. Based on these systems, we will consider hypotheses about the fundamental nature of specific and general disease-suppressive soil microbial communities, explore...

Finding and defining the natural automata acting in living plants: Toward the synthetic biology for robotics and informatics in vivo

PubMed Central

Kawano, Tomonori; Bouteau, François; Mancuso, Stefano

2012-01-01

The automata theory is the mathematical study of abstract machines commonly studied in the theoretical computer science and highly interdisciplinary fields that combine the natural sciences and the theoretical computer science. In the present review article, as the chemical and biological basis for natural computing or informatics, some plants, plant cells or plant-derived molecules involved in signaling are listed and classified as natural sequential machines (namely, the Mealy machines or Moore machines) or finite state automata. By defining the actions (states and transition functions) of these natural automata, the similarity between the computational data processing and plant decision-making processes became obvious. Finally, their putative roles as the parts for plant-based computing or robotic systems are discussed. PMID:23336016

Integrating natural and social science perspectives on plant disease risk, management and policy formulation

PubMed Central

Mills, Peter; Dehnen-Schmutz, Katharina; Ilbery, Brian; Jeger, Mike; Jones, Glyn; Little, Ruth; MacLeod, Alan; Parker, Steve; Pautasso, Marco; Pietravalle, Stephane; Maye, Damian

2011-01-01

Plant diseases threaten both food security and the botanical diversity of natural ecosystems. Substantial research effort is focused on pathogen detection and control, with detailed risk management available for many plant diseases. Risk can be assessed using analytical techniques that account for disease pressure both spatially and temporally. We suggest that such technical assessments of disease risk may not provide an adequate guide to the strategies undertaken by growers and government to manage plant disease. Instead, risk-management strategies need to account more fully for intuitive and normative responses that act to balance conflicting interests between stakeholder organizations concerned with plant diseases within the managed and natural environments. Modes of effective engagement between policy makers and stakeholders are explored in the paper, together with an assessment of such engagement in two case studies of contemporary non-indigenous diseases in one food and in one non-food sector. Finally, a model is proposed for greater integration of stakeholders in policy decisions. PMID:21624923

Integrating natural and social science perspectives on plant disease risk, management and policy formulation.

PubMed

Mills, Peter; Dehnen-Schmutz, Katharina; Ilbery, Brian; Jeger, Mike; Jones, Glyn; Little, Ruth; MacLeod, Alan; Parker, Steve; Pautasso, Marco; Pietravalle, Stephane; Maye, Damian

2011-07-12

Plant diseases threaten both food security and the botanical diversity of natural ecosystems. Substantial research effort is focused on pathogen detection and control, with detailed risk management available for many plant diseases. Risk can be assessed using analytical techniques that account for disease pressure both spatially and temporally. We suggest that such technical assessments of disease risk may not provide an adequate guide to the strategies undertaken by growers and government to manage plant disease. Instead, risk-management strategies need to account more fully for intuitive and normative responses that act to balance conflicting interests between stakeholder organizations concerned with plant diseases within the managed and natural environments. Modes of effective engagement between policy makers and stakeholders are explored in the paper, together with an assessment of such engagement in two case studies of contemporary non-indigenous diseases in one food and in one non-food sector. Finally, a model is proposed for greater integration of stakeholders in policy decisions.

Contour detection improved by context-adaptive surround suppression.

PubMed

Sang, Qiang; Cai, Biao; Chen, Hao

2017-01-01

Recently, many image processing applications have taken advantage of a psychophysical and neurophysiological mechanism, called "surround suppression" to extract object contour from a natural scene. However, these traditional methods often adopt a single suppression model and a fixed input parameter called "inhibition level", which needs to be manually specified. To overcome these drawbacks, we propose a novel model, called "context-adaptive surround suppression", which can automatically control the effect of surround suppression according to image local contextual features measured by a surface estimator based on a local linear kernel. Moreover, a dynamic suppression method and its stopping mechanism are introduced to avoid manual intervention. The proposed algorithm is demonstrated and validated by a broad range of experimental results.

Kainic Acid-Induced Excitotoxicity Experimental Model: Protective Merits of Natural Products and Plant Extracts

PubMed Central

Mohd Sairazi, Nur Shafika; Sirajudeen, K. N. S.; Asari, Mohd Asnizam; Muzaimi, Mustapha; Mummedy, Swamy; Sulaiman, Siti Amrah

2015-01-01

Excitotoxicity is well recognized as a major pathological process of neuronal death in neurodegenerative diseases involving the central nervous system (CNS). In the animal models of neurodegeneration, excitotoxicity is commonly induced experimentally by chemical convulsants, particularly kainic acid (KA). KA-induced excitotoxicity in rodent models has been shown to result in seizures, behavioral changes, oxidative stress, glial activation, inflammatory mediator production, endoplasmic reticulum stress, mitochondrial dysfunction, and selective neurodegeneration in the brain upon KA administration. Recently, there is an emerging trend to search for natural sources to combat against excitotoxicity-associated neurodegenerative diseases. Natural products and plant extracts had attracted a considerable amount of attention because of their reported beneficial effects on the CNS, particularly their neuroprotective effect against excitotoxicity. They provide significant reduction and/or protection against the development and progression of acute and chronic neurodegeneration. This indicates that natural products and plants extracts may be useful in protecting against excitotoxicity-associated neurodegeneration. Thus, targeting of multiple pathways simultaneously may be the strategy to maximize the neuroprotection effect. This review summarizes the mechanisms involved in KA-induced excitotoxicity and attempts to collate the various researches related to the protective effect of natural products and plant extracts in the KA model of neurodegeneration. PMID:26793262

Natural Competence and Recombination in the Plant Pathogen Xylella fastidiosa ▿

PubMed Central

Kung, Stephanie H.; Almeida, Rodrigo P. P.

2011-01-01

Homologous recombination is one of many forces contributing to the diversity, adaptation, and emergence of pathogens. For naturally competent bacteria, transformation is one possible route for the acquisition of novel genetic material. This study demonstrates that Xylella fastidiosa, a generalist bacterial plant pathogen responsible for many emerging plant diseases, is naturally competent and able to homologously recombine exogenous DNA into its genome. Several factors that affect transformation and recombination efficiencies, such as nutrient availability, growth stage, and methylation of transforming DNA, were identified. Recombination was observed in at least one out of every 106 cells when exogenous plasmid DNA was supplied and one out of every 107 cells when different strains were grown together in vitro. Based on previous genomic studies and experimental data presented here, there is mounting evidence that recombination can occur at relatively high rates and could play a large role in shaping the genetic diversity of X. fastidiosa. PMID:21666009

Plants and other natural products used in the management of oral infections and improvement of oral health.

PubMed

Chinsembu, Kazhila C

2016-02-01

Challenges of resistance to synthetic antimicrobials have opened new vistas in the search for natural products. This article rigorously reviews plants and other natural products used in oral health: Punica granatum L. (pomegranate), Matricaria recutita L. (chamomile), Camellia sinensis (L.) Kuntze (green tea), chewing sticks made from Diospyros mespiliformis Hochst. ex A.D.C., Diospyros lycioides Desf., and Salvadora persica L. (miswak), honey and propolis from the manuka tree (Leptospermum scoparium J.R. Forst. & G. Forst.), rhein from Rheum rhabarbarum L. (rhubarb), dried fruits of Vitis vinifera L. (raisins), essential oils, probiotics and mushrooms. Further, the review highlights plants from Africa, Asia, Brazil, Mexico, Europe, and the Middle East. Some of the plants' antimicrobial properties and chemical principles have been elucidated. While the use of natural products for oral health is prominent in resource-poor settings, antimicrobial testing is mainly conducted in the following countries (in decreasing order of magnitude): India, South Africa, Brazil, Japan, France, Egypt, Iran, Mexico, Kenya, Switzerland, Nigeria, Australia, Uganda, and the United Kingdom. While the review exposes a dire gap for more studies on clinical efficacy and toxicity, the following emerging trend was noted: basic research on plants for oral health is mainly done in Brazil, Europe and Australia. Brazil, China, India and New Zealand generally conduct value addition of natural products for fortification of toothpastes. African countries focus on bioprospecting and primary production of raw plants and other natural products with antimicrobial efficacies. The Middle East and Egypt predominantly research on plants used as chewing sticks. More research and funding are needed in the field of natural products for oral health, especially in Africa where oral diseases are fuelled by human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS). Copyright © 2015 Elsevier B

Top predators suppress rather than facilitate plants in a trait-mediated tri-trophic cascade.

PubMed

Griffin, John N; Butler, Jack; Soomdat, Nicole N; Brun, Karen E; Chejanovski, Zachary A; Silliman, Brian R

2011-10-23

Classical ecological theory states that in tri-trophic systems, predators indirectly facilitate plants by reducing herbivore densities through consumption, while more recent work has revealed that predators can generate the same positive effect on plants non-consumptively by inducing changes in herbivore traits (e.g. feeding rates). Based on observations in US salt marshes dominated by vast monocultures of cordgrass, we hypothesized that sit-and-wait substrate-dwelling predators (crabs) could actually strengthen per capita impacts of potent grazers (snails), by non-consumptively inducing a vertical habitat shift of snails to their predation refuge high on canopy leaves that are vulnerable to grazing. A two-month field experiment supported this hypothesis, revealing that predators non-consumptively increased the mean climbing height of snails on grasses, increased grazing damage per leaf and ultimately suppressed cordgrass biomass, relative to controls. While seemingly counterintuitive, our results can be explained by (i) the vulnerability of refuge resources to grazing, and (ii) universal traits that drove the vertical habitat shift--i.e. relative habitat domains of predator and prey, and the hunting mode of the top predator. These results underline the fact that not only should we continue to incorporate non-consumptive effects into our understanding of top-down predator impacts, but we should do so in a spatially explicit manner.

Emodin, a natural inhibitor of protein kinase CK2, suppresses growth, hyphal development, and biofilm formation of Candida albicans.

PubMed

Janeczko, Monika; Masłyk, Maciej; Kubiński, Konrad; Golczyk, Hieronim

2017-06-01

Emodin (1,3,8-trihydroxy-6-methyl-anthraquinone) is a natural secondary plant product, originally isolated from the rhizomes of Rheum palmatum. Many reports show its diuretic, vasorelaxant, antibacterial, antiviral, anti-ulcerogenic, immunosuppressive, hepatoprotective, anti-inflammatory and anticancer potential. Emodin is a pleiotropic molecule capable of interacting with several major molecular targets, e.g. NF-κB, AKT/mTOR and STAT3. The compound can also act as an inhibitor of some protein kinases, with special affinity to protein kinase CK2. The aim of the presented report was to evaluate antifungal properties of emodin and its activity towards CK2 isolated from Candida cells. Our studies revealed that the compound suppressed growth of the cells of reference strains as well as clinical Candida strains, with minimal inhibitory concentration and minimal fungicidal concentration values between 12.5 and 200 μg/mL. Moreover, at a low concentration, the compound was able to effectively stop hyphal formation, thus showing a distinct antivirulent potential. Interestingly, we showed that emodin added to Candida culture inhibited the phosphorylation of many cellular proteins, presumably owing to the inhibition of protein kinase CK2. Notably, the enzyme isolated from the Candida cells was susceptible to emodin with IC 50 of 2.8 μg/mL. Indeed, our computational modelling revealed that emodin was able to occupy the ATP-binding pocket of CK2. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Plant-plant interactions mediate the plastic and genotypic response of Plantago asiatica to CO2: an experiment with plant populations from naturally high CO2 areas.

PubMed

van Loon, Marloes P; Rietkerk, Max; Dekker, Stefan C; Hikosaka, Kouki; Ueda, Miki U; Anten, Niels P R

2016-06-01

The rising atmospheric CO2 concentration ([CO2]) is a ubiquitous selective force that may strongly impact species distribution and vegetation functioning. Plant-plant interactions could mediate the trajectory of vegetation responses to elevated [CO2], because some plants may benefit more from [CO2] elevation than others. The relative contribution of plastic (within the plant's lifetime) and genotypic (over several generations) responses to elevated [CO2] on plant performance was investigated and how these patterns are modified by plant-plant interactions was analysed. Plantago asiatica seeds originating from natural CO2 springs and from ambient [CO2] sites were grown in mono stands of each one of the two origins as well as mixtures of both origins. In total, 1944 plants were grown in [CO2]-controlled walk-in climate rooms, under a [CO2] of 270, 450 and 750 ppm. A model was used for upscaling from leaf to whole-plant photosynthesis and for quantifying the influence of plastic and genotypic responses. It was shown that changes in canopy photosynthesis, specific leaf area (SLA) and stomatal conductance in response to changes in growth [CO2] were mainly determined by plastic and not by genotypic responses. We further found that plants originating from high [CO2] habitats performed better in terms of whole-plant photosynthesis, biomass and leaf area, than those from ambient [CO2] habitats at elevated [CO2] only when both genotypes competed. Similarly, plants from ambient [CO2] habitats performed better at low [CO2], also only when both genotypes competed. No difference in performance was found in mono stands. The results indicate that natural selection under increasing [CO2] will be mainly driven by competitive interactions. This supports the notion that plant-plant interactions have an important influence on future vegetation functioning and species distribution. Furthermore, plant performance was mainly driven by plastic and not by genotypic responses to changes in

Ecological genomics of natural plant populations: the Israeli perspective.

PubMed

Nevo, Eviatar

2009-01-01

The genomic era revolutionized evolutionary population biology. The ecological genomics of the wild progenitors of wheat and barley reviewed here was central in the research program of the Institute of Evolution, University of Haifa, since 1975 ( http://evolution.haifa.ac.il ). We explored the following questions: (1) How much of the genomic and phenomic diversity of wild progenitors of cultivars (wild emmer wheat, Triticum dicoccoides, the progenitor of most wheat, plus wild relatives of the Aegilops species; wild barley, Hordeum spontaneum, the progenitor of cultivated barley; wild oat, Avena sterilis, the progenitor of cultivated oats; and wild lettuce species, Lactuca, the progenitor and relatives of cultivated lettuce) are adaptive and processed by natural selection at both coding and noncoding genomic regions? (2) What is the origin and evolution of genomic adaptation and speciation processes and their regulation by mutation, recombination, and transposons under spatiotemporal variables and stressful macrogeographic and microgeographic environments? (3) How much genetic resources are harbored in the wild progenitors for crop improvement? We advanced ecological genetics into ecological genomics and analyzed (regionally across Israel and the entire Near East Fertile Crescent and locally at microsites, focusing on the "Evolution Canyon" model) hundreds of populations and thousands of genotypes for protein (allozyme) and deoxyribonucleic acid (DNA) (coding and noncoding) diversity, partly combined with phenotypic diversity. The environmental stresses analyzed included abiotic (climatic and microclimatic, edaphic) and biotic (pathogens, demographic) stresses. Recently, we introduced genetic maps, cloning, and transformation of candidate genes. Our results indicate abundant genotypic and phenotypic diversity in natural plant populations. The organization and evolution of molecular and organismal diversity in plant populations, at all genomic regions and

Suppression of a Natural Killer Cell Response by Simian Immunodeficiency Virus Peptides

PubMed Central

Schafer, Jamie L.; Ries, Moritz; Guha, Natasha; Connole, Michelle; Colantonio, Arnaud D.; Wiertz, Emmanuel J.; Wilson, Nancy A.; Kaur, Amitinder; Evans, David T.

2015-01-01

Natural killer (NK) cell responses in primates are regulated in part through interactions between two highly polymorphic molecules, the killer-cell immunoglobulin-like receptors (KIRs) on NK cells and their major histocompatibility complex (MHC) class I ligands on target cells. We previously reported that the binding of a common MHC class I molecule in the rhesus macaque, Mamu-A1*002, to the inhibitory receptor Mamu-KIR3DL05 is stabilized by certain simian immunodeficiency virus (SIV) peptides, but not by others. Here we investigated the functional implications of these interactions by testing SIV peptides bound by Mamu-A1*002 for the ability to modulate Mamu-KIR3DL05+ NK cell responses. Twenty-eight of 75 SIV peptides bound by Mamu-A1*002 suppressed the cytolytic activity of primary Mamu-KIR3DL05+ NK cells, including three immunodominant CD8+ T cell epitopes previously shown to stabilize Mamu-A1*002 tetramer binding to Mamu-KIR3DL05. Substitutions at C-terminal positions changed inhibitory peptides into disinhibitory peptides, and vice versa, without altering binding to Mamu-A1*002. The functional effects of these peptide variants on NK cell responses also corresponded to their effects on Mamu-A1*002 tetramer binding to Mamu-KIR3DL05. In assays with mixtures of inhibitory and disinhibitory peptides, low concentrations of inhibitory peptides dominated to suppress NK cell responses. Consistent with the inhibition of Mamu-KIR3DL05+ NK cells by viral epitopes presented by Mamu-A1*002, SIV replication was significantly higher in Mamu-A1*002+ CD4+ lymphocytes co-cultured with Mamu-KIR3DL05+ NK cells than with Mamu-KIR3DL05- NK cells. These results demonstrate that viral peptides can differentially affect NK cell responses by modulating MHC class I interactions with inhibitory KIRs, and provide a mechanism by which immunodeficiency viruses may evade NK cell responses. PMID:26333068

Methods for suppressing isomerization of olefin metathesis products

DOEpatents

Firth, Bruce E.; Kirk, Sharon E.; Gavaskar, Vasudeo S.

2015-09-22

A method for suppressing isomerization of an olefin metathesis product produced in a metathesis reaction includes adding an isomerization suppression agent to a mixture that includes the olefin metathesis product and residual metathesis catalyst from the metathesis reaction under conditions that are sufficient to passivate at least a portion of the residual metathesis catalyst. The isomerization suppression agent is phosphorous acid, a phosphorous acid ester, phosphinic acid, a phosphinic acid ester or combinations thereof. Methods of refining natural oils are described.

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

PubMed

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

2009-01-01

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

In vivo assessment of plant extracts for control of plant diseases: A sesquiterpene ketolactone isolated from Curcuma zedoaria suppresses wheat leaf rust.

PubMed

Han, Jae Woo; Shim, Sang Hee; Jang, Kyoung Soo; Choi, Yong Ho; Dang, Quang Le; Kim, Hun; Choi, Gyung Ja

2018-02-01

As an alternative to synthetic pesticides, natural materials such as plant extracts and microbes have been considered to control plant diseases. In this study, methanol extracts of 120 plants were explored for in vivo antifungal activity against Rhizoctonia solani, Botrytis cinerea, Phytophthora infestans, Puccinia triticina, and Blumeria graminis f. sp. hordei. Of the 120 plant extracts, eight plant extracts exhibited a disease control efficacy of more than 90% against at least one of five plant diseases. In particular, a methanol extract of Curcuma zedoaria rhizomes exhibited strong activity against wheat leaf rust caused by P. triticina. When the C. zedoaria methanol extracts were partitioned with various solvents, the layers of n-hexane, methylene chloride, and ethyl acetate showed disease control values of 100, 80, and 43%, respectively, against wheat leaf rust. From the C. zedoaria rhizome extracts, an antifungal substance was isolated and identified as a sesquiterpene ketolactone based on the mass and nuclear magnetic resonance spectral data. The active compound controlled the development of rice sheath blight, wheat leaf rust, and tomato late blight. Considering the in vivo antifungal activities of the sesquiterpene ketolactone and the C. zedoaria extracts, these results suggest that C. zedoaria can be used as a potent fungicide in organic agriculture.

Suppression of Plant Immune Responses by the Pseudomonas savastanoi pv. savastanoi NCPPB 3335 Type III Effector Tyrosine Phosphatases HopAO1 and HopAO2

PubMed Central

Castañeda-Ojeda, María Pilar; Moreno-Pérez, Alba; Ramos, Cayo; López-Solanilla, Emilia

2017-01-01

The effector repertoire of the olive pathogen P. savastanoi pv. savastanoi NCPPB 3335 includes two members of the HopAO effector family, one of the most diverse T3E families of the P. syringae complex. The study described here explores the phylogeny of these dissimilar members, HopAO1 and HopAO2, among the complex and reveals their activities as immune defense suppressors. Although HopAO1 is predominantly encoded by phylogroup 3 strains isolated from woody organs of woody hosts, both HopAO1 and HopAO2 are phylogenetically clustered according to the woody/herbaceous nature of their host of isolation, suggesting host specialization of the HopAO family across the P. syringae complex. HopAO1 and HopAO2 translocate into plant cells and show hrpL-dependent expression, which allows their classification as actively deployed type III effectors. Our data also show that HopAO1 and HopAO2 possess phosphatase activity, a hallmark of the members of this family. Both of them exert an inhibitory effect on early plant defense responses, such as ROS production and callose deposition, and are able to suppress ETI responses induced by the effectorless polymutant of P. syringae pv. tomato DC3000 (DC3000D28E) in Nicotiana. Moreover, we demonstrate that a ΔhopAO1 mutant of P. savastanoi NCPBB 3335 exhibits a reduced fitness and virulence in olive plants, which supports the relevance of this effector during the interaction of this strain with its host plants. This work contributes to the field with the first report regarding functional analysis of HopAO homologs encoded by P. syringae or P. savastanoi strains isolated from woody hosts. PMID:28529516

Role of Bacterial Communities in the Natural Suppression of Rhizoctonia solani Bare Patch Disease of Wheat (Triticum aestivum L.)

PubMed Central

Yin, Chuntao; Hulbert, Scot H.; Schroeder, Kurtis L.; Mavrodi, Olga; Mavrodi, Dmitri; Dhingra, Amit; Schillinger, William F.

2013-01-01

Rhizoctonia bare patch and root rot disease of wheat, caused by Rhizoctonia solani AG-8, develops as distinct patches of stunted plants and limits the yield of direct-seeded (no-till) wheat in the Pacific Northwest of the United States. At the site of a long-term cropping systems study near Ritzville, WA, a decline in Rhizoctonia patch disease was observed over an 11-year period. Bacterial communities from bulk and rhizosphere soil of plants from inside the patches, outside the patches, and recovered patches were analyzed by using pyrosequencing with primers designed for 16S rRNA. Taxa in the class Acidobacteria and the genus Gemmatimonas were found at higher frequencies in the rhizosphere of healthy plants outside the patches than in that of diseased plants from inside the patches. Dyella and Acidobacteria subgroup Gp7 were found at higher frequencies in recovered patches. Chitinophaga, Pedobacter, Oxalobacteriaceae (Duganella and Massilia), and Chyseobacterium were found at higher frequencies in the rhizosphere of diseased plants from inside the patches. For selected taxa, trends were validated by quantitative PCR (qPCR), and observed shifts of frequencies in the rhizosphere over time were duplicated in cycling experiments in the greenhouse that involved successive plantings of wheat in Rhizoctonia-inoculated soil. Chryseobacterium soldanellicola was isolated from the rhizosphere inside the patches and exhibited significant antagonism against R. solani AG-8 in vitro and in greenhouse tests. In conclusion, we identified novel bacterial taxa that respond to conditions affecting bare patch disease symptoms and that may be involved in suppression of Rhizoctonia root rot and bare batch disease. PMID:24056471

Naturally occurring radioactive material (NORM) from a former phosphoric acid processing plant.

PubMed

Beddow, H; Black, S; Read, D

2006-01-01

In recent years there has been an increasing awareness of the radiological impact of non-nuclear industries that extract and/or process ores and minerals containing naturally occurring radioactive material (NORM). These industrial activities may result in significant radioactive contamination of (by-) products, wastes and plant installations. In this study, scale samples were collected from a decommissioned phosphoric acid processing plant. To determine the nature and concentration of NORM retained in pipe-work and associated process plant, four main areas of the site were investigated: (1) the 'Green Acid Plant', where crude acid was concentrated; (2) the green acid storage tanks; (3) the Purified White Acid (PWA) plant, where inorganic impurities were removed; and (4) the solid waste, disposed of on-site as landfill. The scale samples predominantly comprise the following: fluorides (e.g. ralstonite); calcium sulphate (e.g. gypsum); and an assemblage of mixed fluorides and phosphates (e.g. iron fluoride hydrate, calcium phosphate), respectively. The radioactive inventory is dominated by 238U and its decay chain products, and significant fractionation along the series occurs. Compared to the feedstock ore, elevated concentrations (< or =8.8 Bq/g) of 238U were found to be retained in installations where the process stream was rich in fluorides and phosphates. In addition, enriched levels (< or =11 Bq/g) of 226Ra were found in association with precipitates of calcium sulphate. Water extraction tests indicate that many of the scales and waste contain significantly soluble materials and readily release radioactivity into solution.

Spatial arrangements affect suppression of invasive Alternanthera philoxeroides by native Hemarthria compressa

NASA Astrophysics Data System (ADS)

Liao, Jianxiong; Tao, Min; Jiang, Mingxi

2014-08-01

It has been hypothesized that differences in spatial arrangements change the relative frequency of intra- and interspecific encounters between plant species. Manipulating spatial arrangement may play a role in invasive plant suppression when native species are used as competitors against introduced species. In this study, a replacement series experiment was performed to investigate the effects of intraspecifically random and aggregated spatial arrangements on interactions between the native plant Hemarthria compressa and the invasive plant Alternanthera philoxeroides, to test the possibility and effectiveness of H. compressa in suppressing A. philoxeroides. When both species were planted in intraspecifically random spatial patterns, H. compressa had a competitive advantage over A. philoxeroides at relative densities of 2:2 and 3:1. However, aggregation increased the strength, and therefore the cost, of intraspecific competition in H. compressa, resulting in lower biomass production, which reduced its effectiveness as an interspecific competitor. As the relative density of H. compressa in mixtures decreased, plants allocated more biomass to belowground parts, but fewer interspecific encounters lowered its inhibitory effects on A. philoxeroides. The results not only confirm that the frequency of conspecific and heterospecific encounters can influence competitive outcomes, but also suggest that a reduction in the degree of spatial aggregation in H. compressa and an increase in its relative densities may be essential to increase the suppression of A. philoxeroides.

A review of the use of engineered nanomaterials to suppress plant disease and enhance crop yield

NASA Astrophysics Data System (ADS)

Servin, Alia; Elmer, Wade; Mukherjee, Arnab; De la Torre-Roche, Roberto; Hamdi, Helmi; White, Jason C.; Bindraban, Prem; Dimkpa, Christian

2015-02-01

Nanotechnology has the potential to play a critical role in global food production, food security, and food safety. The applications of nanotechnology in agriculture include fertilizers to increase plant growth and yield, pesticides for pest and disease management, and sensors for monitoring soil quality and plant health. Over the past decade, a number of patents and products incorporating nanomaterials into agricultural practices (e.g., nanopesticides, nanofertilizers, and nanosensors) have been developed. The collective goal of all of these approaches is to enhance the efficiency and sustainability of agricultural practices by requiring less input and generating less waste than conventional products and approaches. This review evaluates the current literature on the use of nanoscale nutrients (metals, metal oxides, carbon) to suppress crop disease and subsequently enhance growth and yield. Notably, this enhanced yield may not only be directly linked to the reduced presence of pathogenic organisms, but also to the potential nutritional value of the nanoparticles themselves, especially for the essential micronutrients necessary for host defense. We also posit that these positive effects are likely a result of the greater availability of the nutrients in the "nano" form. Last, we offer comments on the current regulatory perspective for such applications.

Autophagy-induced RelB/p52 activation mediates tumour-associated macrophage repolarisation and suppression of hepatocellular carcinoma by natural compound baicalin

PubMed Central

Tan, H-Y; Wang, N; Man, K; Tsao, S-W; Che, C-M; Feng, Y

2015-01-01

The plasticity of tumour-associated macrophages (TAMs) has implicated an influential role in hepatocellular carcinoma (HCC). Repolarisation of TAM towards M1 phenotype characterises an immune-competent microenvironment that favours tumour regression. To investigate the role and mechanism of TAM repolarisation in suppression of HCC by a natural compound baicalin, Orthotopic HCC implantation model was used to investigate the effect of baicalin on HCC; liposome-clodronate was introduced to suppress macrophage populations in mice; bone marrow-derived monocytes (BMDMs) were induced to unpolarised, M1-like, M2-like macrophages and TAM using different conditioned medium. We observed that oral administration of baicalin (50 mg/kg) completely blocked orthotopic growth of implanted HCC. Suppression of HCC by baicalin was diminished when mice macrophage was removed by clodronate treatment. Baicalin induced repolarisation of TAM to M1-like phenotype without specific toxicity to either phenotype of macrophages. Baicalin initiated TAM reprogramming to M1-like macrophage, and promoted pro-inflammatory cytokines production. Co-culturing of HCC cells with baicalin-treated TAMs resulted in reduced proliferation and motility in HCC. Baicalin had minimal effect on derivation of macrophage polarisation factors by HCC cells, while directly induced repolarisation of TAM and M2-like macrophage. This effect was associated with elevated autophagy, and transcriptional activation of RelB/p52 pathway. Suppression of autophagy or RelB abolished skewing of baicalin-treated TAM. Autophagic degradation of TRAF2 in baicalin-treated TAM might be responsible for RelB/p52 activation. Our findings unveil the essential role of TAM repolarisation in suppressive effect of baicalin on HCC, which requires autophagy-associated activation of RelB/p52. PMID:26492375

Plant Natural Products Calycosin and Gallic Acid Synergistically Attenuate Neutrophil Infiltration and Subsequent Injury in Isoproterenol-Induced Myocardial Infarction: A Possible Role for Leukotriene B4 12-Hydroxydehydrogenase?

PubMed Central

Cheng, Yuanyuan; Tse, Hung Fat; Le, X. Chris; Rong, Jianhui

2015-01-01

Leukotriene B4 12-hydroxydehydrogenase (LTB4DH) catalyzes the oxidation of proinflammatory LTB4 into less bioactive 12-oxo-LTB4. We recently discovered that LTB4DH was induced by two different natural products in combination. We previously isolated gallic acid from Radix Paeoniae through a bioactivity-guided fractionation procedure. The purpose of this study is to test the hypothesis that LTB4DH inducers may suppress neutrophil-mediated inflammation in myocardial infarction. We first isolated the active compound(s) from another plant, Radix Astragali, by the similar strategy. By evaluating LTB4DH induction, we identified calycosin and formononetin from Radix Astragali by HPLC-ESI-MS technique. We confirmed that gallic acid and commercial calycosin or formononetin could synergistically induce LTB4DH expression in HepG2 cells and human neutrophils. Moreover, calycosin and gallic acid attenuated the effects of LTB4 on the survival and chemotaxis of neutrophil cell culture. We further demonstrated that calycosin and gallic acid synergistically suppressed neutrophil infiltration and protected cardiac integrity in the isoproterenol-induced mice model of myocardial infarction. Calycosin and gallic acid dramatically suppressed isoproterenol-induced increase in myeloperoxidase (MPO) activity and malondialdehyde (MDA) level. Collectively, our results suggest that LTB4DH inducers (i.e., calycosin and gallic acid) may be a novel combined therapy for the treatment of neutrophil-mediated myocardial injury. PMID:26265982

Trait differences between naturalized and invasive plant species independent of residence time and phylogeny.

PubMed

Gallagher, R V; Randall, R P; Leishman, M R

2015-04-01

The ability to predict which alien plants will transition from naturalized to invasive prior to their introduction to novel regions is a key goal for conservation and has the potential to increase the efficacy of weed risk assessment (WRA). However, multiple factors contribute to plant invasion success (e.g., functional traits, range characteristics, residence time, phylogeny), and they all must be taken into account simultaneously in order to identify meaningful correlates of invasion success. We compiled 146 pairs of phylogenetically paired (congeneric) naturalized and invasive plant species in Australia with similar minimum residence times (i.e., time since introduction in years). These pairs were used to test for differences in 5 functional traits (flowering duration, leaf size, maximum height, specific leaf area [SLA], seed mass) and 3 characteristics of species' native ranges (biome occupancy, mean annual temperature, and rainfall breadth) between naturalized and invasive species. Invasive species, on average, had larger SLA, longer flowering periods, and were taller than their congeneric naturalized relatives. Invaders also exhibited greater tolerance for different environmental conditions in the native range, where they occupied more biomes and a wider breadth of rainfall and temperature conditions than naturalized congeners. However, neither seed mass nor leaf size differed between pairs of naturalized and invasive species. A key finding was the role of SLA in distinguishing between naturalized and invasive pairs. Species with high SLA values were typically associated with faster growth rates, more rapid turnover of leaf material, and shorter lifespans than those species with low SLA. This suite of characteristics may contribute to the ability of a species to transition from naturalized to invasive across a wide range of environmental contexts and disturbance regimes. Our findings will help in the refinement of WRA protocols, and we advocate the inclusion

Economic and Environmental Assessment of Natural Gas Plants with Carbon Capture and Storage (NGCC-CCS)

EPA Science Inventory

The CO2 intensity of electricity produced by state-of-the-art natural gas combined-cycle turbines (NGCC) isapproximately one-third that of the U.S. fleet of existing coal plants. Compared to new nuclear plants and coal plantswith integrated carbon capture, NGCC has a lower invest...

Natural radionuclides in waste water discharged from coal-fired power plants in Serbia.

PubMed

Janković, Marija M; Todorović, Dragana J; Sarap, Nataša B; Krneta Nikolić, Jelena D; Rajačić, Milica M; Pantelić, Gordana K

2016-12-01

Investigation of the natural radioactivity levels in water around power plants, as well as in plants, coal, ash, slag and soil, and to assess the associated radiation hazard is becoming an emerging and interesting topic. This paper is focused on the results of the radioactivity analysis in waste water samples from five coal-fired power plants in Serbia (Nikola Tesla A, Nikola Tesla B, Kolubara, Morava and Kostolac), which were analyzed in the period 2003-2015. River water samples taken upstream and downstream from the power plants, drain water and overflow water were analyzed. In the water samples gamma spectrometry analysis was performed as well as determination of gross alpha and beta activity. Natural radionuclide 40 K was detected by gamma spectrometry, while the concentrations of other radionuclides, 226 Ra, 235 U and 238 U, usually were below the minimum detection activity (MDA). 232 Th and artificial radionuclide 137 Cs were not detected in these samples. Gross alpha and beta activities were determined by the α/β low level proportional counter Thermo Eberline FHT 770 T. In the analyzed samples, gross alpha activity ranged from MDA to 0.47 Bq L - 1 , while the gross beta activity ranged from MDA to 1.55 Bq L - 1 .

Bacillus thuringiensis plants expressing Cry1Ac, Cry2Ab and Cry1F are not toxic to the assassin bug, Zelus renardii

USDA-ARS?s Scientific Manuscript database

Cotton and maize delivering insecticidal crystal (Cry) proteins from the bacterium, Bacillus thuringiensis (Bt), have been commercialized since 1996. Bt plants are subjected to environmental risk assessments for non-target organisms, especially natural enemies that suppress pest populations. In th...

18β-Glycyrrhetinic Acid, a Novel Naturally Derived Agent, Suppresses Prolactin Hyperactivity and Reduces Antipsychotic-Induced Hyperprolactinemia in In Vitro and In Vivo Models.

PubMed

Wang, Di; Zhang, Yongfeng; Wang, Chunyue; Jia, Dongxu; Cai, Guangsheng; Lu, Jiahui; Wang, Di; Zhang, Zhang-Jin

2016-09-01

The purpose of this study was to examine the effects of 18β-glycyrrhetinic acid (GA), a novel naturally derived agent, in suppressing prolactin (PRL) hyperactivity and reducing antipsychotic-induced hyperprolactinemia (hyperPRL) and the underlying mechanisms in in vitro and in vivo models. GA treatment for 24 h inhibited PRL synthesis and secretion in MMQ cells and cultured pituitary cells in a dose-dependent fashion; but this effect was not reproduced in GH3 cells that lack the expression of functional dopamine D2 receptors. GA suppressed elevated PRL level and growth hormone, and normalized several sex hormones in a rat model of hyperPRL, produced by repeated injection of the dopamine blocker metoclopramide. GA also modulated the expression 5-HT1A and 5-HT2A receptors in both in vivo and in vitro models. These results indicate that GA is effective in suppressing PRL hyperactivity caused by the blockade of dopamine D2 receptors. This suppressive effect of GA may be related to its modulation of the serotonergic system. This study provides additional evidence in support of GA as an adjunct for the treatment of hyperPRL.

Autoimmune Lymphoproliferative Syndrome-FAS Patients Have an Abnormal Regulatory T Cell (Treg) Phenotype but Display Normal Natural Treg-Suppressive Function on T Cell Proliferation.

PubMed

Mazerolles, Fabienne; Stolzenberg, Marie-Claude; Pelle, Olivier; Picard, Capucine; Neven, Benedicte; Fischer, Alain; Magerus-Chatinet, Aude; Rieux-Laucat, Frederic

2018-01-01

Autoimmune lymphoproliferative syndrome (ALPS) with FAS mutation (ALPS-FAS) is a nonmalignant, noninfectious, lymphoproliferative disease with autoimmunity. Given the central role of natural regulatory T cells (nTregs) in the control of lymphoproliferation and autoimmunity, we assessed nTreg-suppressive function in 16 patients with ALPS-FAS. The proportion of CD25 high CD127 low Tregs was lower in ALPS-FAS patients than in healthy controls. This subset was correlated with a reduced CD25 expression in CD3 + CD4 + T cells from ALPS patients and thus an abnormally low proportion of CD25 high FOXP3 + Helios + T cells. The ALPS patients also displayed a high proportion of naïve Treg (FOXP3 low CD45RA + ) and an unusual subpopulation (CD4 + CD127 low CD15s + CD45RA + ). Despite this abnormal phenotype, the CD25 high CD127 low Tregs' suppressive function was unaffected. Furthermore, conventional T cells from FAS -mutated patients showed normal levels of sensitivity to Treg suppression. An abnormal Treg phenotype is observed in circulating lymphocytes of ALPS patients. However, these Tregs displayed a normal suppressive function on T effector proliferation in vitro . This is suggesting that lymphoproliferation observed in ALPS patients does not result from Tregs functional defect or T effector cells insensitivity to Tregs suppression.

Selecting native perennial plants for ecological intensification in Mediterranean greenhouse horticulture.

PubMed

Rodríguez, E; González, M; Paredes, D; Campos, M; Benítez, E

2017-12-04

Natural control by predators and parasitoids provides an important and often unnoticed ecosystem service to agricultural landscapes by reducing pest populations in crops. The current model of horticultural intensification in south-eastern Spain produces high yields but has also resulted in a landscape almost completely covered by plastic. Promoting natural areas among greenhouses could enhance biodiversity, by being beneficial insects, and reduce pest pressure outdoors. The first step is to ascertain how pests and their natural enemies (NEs) use Mediterranean vegetation for selecting the best plants for pest suppression outdoors. The abundance of the two major horticultural pests, the tobacco whitefly, Bemisia tabaci, and the western flower thrips, Frankliniella occidentalis, together with their NEs, were assayed in 22 flowering perennial plants, which were newly planted in an experimental field surrounded by greenhouses. Eight plant species were identified as the most critical species for sustaining pest populations outdoors. A set of five plant species supported a medium level of pests, and another set of ten plant species supported the lowest level of both pests. Tobacco whitefly occurred in a few plants species, whereas western flower thrips occurred on almost all the plant species studied, and was favoured by the presence of flowers in perennial plants. The results suggest that plant diversity may provide relatively few acceptable host plants for tobacco whitefly than for western flower thrips. NEs were generally collected in plants that also supported abundance of pests, indicating that host/prey availability, more than food resources from flowers, was a stronger predictor of NE abundance in perennial plants. Field trials using the plants with the lowest host acceptance by pests are needed in order to ascertain whether pest abundance outdoors is reduced.

Biochar-enhanced composts reduce the potential leaching of nutrients and heavy metals and suppress plant-parasitic nematodes in excessively fertilized cucumber soils.

PubMed

Cao, Yune; Gao, Yanming; Qi, Yanbin; Li, Jianshe

2018-03-01

Excessive fertilization is a common agricultural practice that has largely reduced soil nutrient retention capacity and led to nutrient leaching in China. To reduce nutrient leaching, in this study, we evaluated the application of biochar, compost, and biochar-compost on soil properties, leaching water quality, and cucumber plant growth in soils with different nutrient levels. In general, the concentrations of nutrients and heavy metals in leaching water were higher under high-nutrient conditions than under low-nutrient conditions. Both biochar and compost efficiently enhanced soil cation exchange capacity (CEC), water holding capacity (WHC), and microbial biomass carbon (MBC), nitrogen (MBN), and phosphorus (MBP), reduced the potential leaching of nutrients and heavy metals, and improved plant growth. The efficiency of biochar and compost in soil CEC, WHC, MBC, MBN, and MBP and plant growth was enhanced when applied jointly. In addition, biochar and biochar-enhanced compost efficiently suppressed plant-parasitic nematode infestation in a soil with high levels of both N and P. Our results suggest that biochar-enhanced compost can reduce the potential environmental risks in excessively fertilized vegetable soils.

Chitin amendment increases soil suppressiveness toward plant pathogens and modulates the actinobacterial and oxalobacteraceal communities in an experimental agricultural field.

PubMed

Cretoiu, Mariana Silvia; Korthals, Gerard W; Visser, Johnny H M; van Elsas, Jan Dirk

2013-09-01

A long-term experiment on the effect of chitin addition to soil on the suppression of soilborne pathogens was set up and monitored for 8 years in an experimental field, Vredepeel, The Netherlands. Chitinous matter obtained from shrimps was added to soil top layers on two different occasions, and the suppressiveness of soil toward Verticillium dahliae, as well as plant-pathogenic nematodes, was assessed, in addition to analyses of the abundances and community structures of members of the soil microbiota. The data revealed that chitin amendment had raised the suppressiveness of soil, in particular toward Verticillium dahliae, 9 months after the (second) treatment, extending to 2 years following treatment. Moreover, major effects of the added chitin on the soil microbial communities were detected. First, shifts in both the abundances and structures of the chitin-treated soil microbial communities, both of total soil bacteria and fungi, were found. In addition, the abundances and structures of soil actinobacteria and the Oxalobacteraceae were affected by chitin. At the functional gene level, the abundance of specific (family-18 glycoside hydrolase) chitinase genes carried by the soil bacteria also revealed upshifts as a result of the added chitin. The effects of chitin noted for the Oxalobacteraceae were specifically related to significant upshifts in the abundances of the species Duganella violaceinigra and Massilia plicata. These effects of chitin persisted over the time of the experiment.

Chitin Amendment Increases Soil Suppressiveness toward Plant Pathogens and Modulates the Actinobacterial and Oxalobacteraceal Communities in an Experimental Agricultural Field

PubMed Central

Cretoiu, Mariana Silvia; Korthals, Gerard W.; Visser, Johnny H. M.

2013-01-01

A long-term experiment on the effect of chitin addition to soil on the suppression of soilborne pathogens was set up and monitored for 8 years in an experimental field, Vredepeel, The Netherlands. Chitinous matter obtained from shrimps was added to soil top layers on two different occasions, and the suppressiveness of soil toward Verticillium dahliae, as well as plant-pathogenic nematodes, was assessed, in addition to analyses of the abundances and community structures of members of the soil microbiota. The data revealed that chitin amendment had raised the suppressiveness of soil, in particular toward Verticillium dahliae, 9 months after the (second) treatment, extending to 2 years following treatment. Moreover, major effects of the added chitin on the soil microbial communities were detected. First, shifts in both the abundances and structures of the chitin-treated soil microbial communities, both of total soil bacteria and fungi, were found. In addition, the abundances and structures of soil actinobacteria and the Oxalobacteraceae were affected by chitin. At the functional gene level, the abundance of specific (family-18 glycoside hydrolase) chitinase genes carried by the soil bacteria also revealed upshifts as a result of the added chitin. The effects of chitin noted for the Oxalobacteraceae were specifically related to significant upshifts in the abundances of the species Duganella violaceinigra and Massilia plicata. These effects of chitin persisted over the time of the experiment. PMID:23811512

Plants' Metabolites as Potential Antiobesity Agents

PubMed Central

Gooda Sahib, Najla; Saari, Nazamid; Ismail, Amin; Khatib, Alfi; Mahomoodally, Fawzi; Abdul Hamid, Azizah

2012-01-01

Obesity and obesity-related complications are on the increase both in the developed and developing world. Since existing pharmaceuticals fail to come up with long-term solutions to address this issue, there is an ever-pressing need to find and develop new drugs and alternatives. Natural products, particularly medicinal plants, are believed to harbor potential antiobesity agents that can act through various mechanisms either by preventing weight gain or promoting weight loss amongst others. The inhibition of key lipid and carbohydrate hydrolyzing and metabolizing enzymes, disruption of adipogenesis, and modulation of its factors or appetite suppression are some of the plethora of targeted approaches to probe the antiobesity potential of medicinal plants. A new technology such as metabolomics, which deals with the study of the whole metabolome, has been identified to be a promising technique to probe the progression of diseases, elucidate their pathologies, and assess the effects of natural health products on certain pathological conditions. This has been applied to drug research, bone health, and to a limited extent to obesity research. This paper thus endeavors to give an overview of those plants, which have been reported to have antiobesity effects and highlight the potential and relevance of metabolomics in obesity research. PMID:22666121

Diversity and natural functions of antibiotics produced by beneficial and plant pathogenic bacteria.

PubMed

Raaijmakers, Jos M; Mazzola, Mark

2012-01-01

Soil- and plant-associated environments harbor numerous bacteria that produce antibiotic metabolites with specific or broad-spectrum activities against coexisting microorganisms. The function and ecological importance of antibiotics have long been assumed to yield a survival advantage to the producing bacteria in the highly competitive but resource-limited soil environments through direct suppression. Although specific antibiotics may enhance producer persistence when challenged by competitors or predators in soil habitats, at subinhibitory concentrations antibiotics exhibit a diversity of other roles in the life history of the producing bacteria. Many processes modulated by antibiotics may be inherently critical to the producing bacterium, such as the acquisition of substrates or initiation of developmental changes that will ensure survival under stressful conditions. Antibiotics may also have roles in more complex interactions, including in virulence on host plants or in shaping the outcomes of multitrophic interactions. The innate functions of antibiotics to producing bacteria in their native ecosystem are just beginning to emerge, but current knowledge already reveals a breadth of activities well beyond the historical perspective of antibiotics as weaponry in microbial conflicts.

The nature of plant species

PubMed Central

Rieseberg, Loren H.; Wood, Troy E.; Baack, Eric J.

2008-01-01

Many botanists doubt the existence of plant species1–5, viewing them as arbitrary constructs of the human mind, as opposed to discrete, objective entities that represent reproductively independent lineages or ‘units of evolution’. However, the discreteness of plant species and their correspondence with reproductive communities have not been tested quantitatively, allowing zoologists to argue that botanists have been overly influenced by a few ‘botanical horror stories’, such as dandelions, blackberries and oaks6,7. Here we analyse phenetic and/or crossing relationships in over 400 genera of plants and animals. We show that although discrete phenotypic clusters exist in most genera (>80%), the correspondence of taxonomic species to these clusters is poor (<60%) and no different between plants and animals. Lack of congruence is caused by polyploidy, asexual reproduction and over-differentiation by taxonomists, but not by contemporary hybridization. Nonetheless, crossability data indicate that 70% of taxonomic species and 75% of phenotypic clusters in plants correspond to reproductively independent lineages (as measured by postmating isolation), and thus represent biologically real entities. Contrary to conventional wisdom8, plant species are more likely than animal species to represent reproductively independent lineages. PMID:16554818

The nature of plant species.

PubMed

Rieseberg, Loren H; Wood, Troy E; Baack, Eric J

2006-03-23

Many botanists doubt the existence of plant species, viewing them as arbitrary constructs of the human mind, as opposed to discrete, objective entities that represent reproductively independent lineages or 'units of evolution'. However, the discreteness of plant species and their correspondence with reproductive communities have not been tested quantitatively, allowing zoologists to argue that botanists have been overly influenced by a few 'botanical horror stories', such as dandelions, blackberries and oaks. Here we analyse phenetic and/or crossing relationships in over 400 genera of plants and animals. We show that although discrete phenotypic clusters exist in most genera (> 80%), the correspondence of taxonomic species to these clusters is poor (< 60%) and no different between plants and animals. Lack of congruence is caused by polyploidy, asexual reproduction and over-differentiation by taxonomists, but not by contemporary hybridization. Nonetheless, crossability data indicate that 70% of taxonomic species and 75% of phenotypic clusters in plants correspond to reproductively independent lineages (as measured by postmating isolation), and thus represent biologically real entities. Contrary to conventional wisdom, plant species are more likely than animal species to represent reproductively independent lineages.

Use of Plant and Herb Derived Medicine for Therapeutic Usage in Cardiology.

PubMed

Koo, Ye Eun; Song, Jiwon; Bae, Soochan

2018-04-22

Cardiovascular diseases (CVDs) have become prominent in mortality and morbidity rates. Prevalent cardiovascular conditions, such as hypertension, atherosclerosis and oxidative stress, are increasing at an alarming rate. Conventional drugs have been associated with adverse effects, suggesting a need for an alternative measure to ameliorate CVD. A number of plant- and herb-derived preventative food and therapeutic drugs for cardiovascular conditions are progressively used for their various benefits. Naturally derived food and drugs have fewer side effects because they come from natural elements; preventative food, such as grape seed, inhibits changes of histopathology and biomarkers in vital organs whereas therapeutic drugs, for instance Xanthone, improve heart functions by suppressing oxidative stress of myocyte. This review closely examines the various plant- and herb-derived drugs that have assumed an essential role in treating inflammation and oxidative stress for prevalent cardiovascular conditions. Furthermore, the use of plant-derived medicine with other synthetic particles, such as nanoparticles, for targeted therapy is investigated for its effective clinical use in the future.

A checklist of the vascular plants in Abbott Creek Research Natural Area, Oregon.

Treesearch

Rod Mitchell

1979-01-01

This paper is a checklist of 277 vascular plant taxa that have been collected or encountered in Abbott Creek Research Natural Area, Oregon; a brief description of five forested and two nonforested vegetation types is included.

Wall extensibility: its nature, measurement and relationship to plant cell growth

NASA Technical Reports Server (NTRS)

Cosgrove, D. J.

1993-01-01

Expansive growth of plant cells is controlled principally by processes that loosen the wall and enable it to expand irreversibly. The central role of wall relaxation for cell expansion is reviewed. The most common methods for assessing the extension properties of plant cell walls ( wall extensibility') are described, categorized and assessed critically. What emerges are three fundamentally different approaches which test growing cells for their ability (a) to enlarge at different values of turgor, (b) to induce wall relaxation, and (c) to deform elastically or plastically in response to an applied tensile force. Analogous methods with isolated walls are similarly reviewed. The results of these different assays are related to the nature of plant cell growth and pertinent biophysical theory. I argue that the extensibilities' measured by these assays are fundamentally different from one another and that some are more pertinent to growth than others.

The Chemistry and Biological Activities of Natural Products from Northern African Plant Families: From Taccaceae to Zygophyllaceae.

PubMed

Ntie-Kang, Fidele; Njume, Leonel E; Malange, Yvette I; Günther, Stefan; Sippl, Wolfgang; Yong, Joseph N

2016-04-01

Traditional medicinal practices have a profound influence on the daily lives of people living in developing countries, particularly in Africa, since the populations cannot generally afford the cost of Western medicines. We have undertaken to investigate the correlation between the uses of plants in Traditional African medicine and the biological activities of the derived natural products, with the aim to validate the use of traditional medicine in Northern African communities. The literature is covered for the period 1959-2015 and part III of this review series focuses on plant families with names beginning with letters T to Z. The authors have focused on curating data from journals in natural products and phytomedicine. Within each journal home page, a query search based on country name was conducted. All articles "hits" were then verified, one at a time, that the species was harvested within the Northern African geographical regions. The current data partly constitutes the bases for the development of the Northern African natural compounds database. The review discusses 284 plant-based natural compounds from 34 species and 11 families. It was observed that the ethnobotanical uses of less than 40 % of the plant species surveyed correlated with the bioactivities of compounds identified.

Lessons from natural and artificial polyploids in higher plants.

PubMed

Hegarty, M; Coate, J; Sherman-Broyles, S; Abbott, R; Hiscock, S; Doyle, J

2013-01-01

Polyploidy in higher plants is a major source of genetic novelty upon which selection may act to drive evolution, as evidenced by the widespread success of polyploid species in the wild. However, research into the effects of polyploidy can be confounded by the entanglement of several processes: genome duplication, hybridisation (allopolyploidy is frequent in plants) and subsequent evolution. The discovery of the chemical agent colchicine, which can be used to produce artificial polyploids on demand, has enabled scientists to unravel these threads and understand the complex genomic changes involved in each. We present here an overview of lessons learnt from studies of natural and artificial polyploids, and from comparisons between the 2, covering basic cellular and metabolic consequences through to alterations in epigenetic gene regulation, together with 2 in-depth case studies in Senecio and Glycine. See also the sister article focusing on animals by Arai and Fujimoto in this themed issue. Copyright © 2013 S. Karger AG, Basel.

Methods for suppressing isomerization of olefin metathesis products

DOEpatents

Firth, Bruce E.; Kirk, Sharon E.

2015-10-27

A method for suppressing isomerization of an olefin metathesis product produced in a metathesis reaction includes adding an isomerization suppression agent that includes nitric acid to a mixture that includes the olefin metathesis product and residual metathesis catalyst from the metathesis reaction under conditions that are sufficient to passivate at least a portion of the residual metathesis catalyst. Methods of refining a natural oil are described.

Plant tendrils: Nature's hygroscopic springs

NASA Astrophysics Data System (ADS)

Gerbode, Sharon; Puzey, Joshua; McCormick, Andrew; Mahadevan, L.

2012-02-01

Plant tendrils are specialized climbing organs that have fascinated biologists and physicists alike for centuries. Initially straight tendrils attach at the tip to an elevated rigid support and then winch the plant upward by coiling into a helical morphology characterized by two helices of opposite handedness connected by a helical perversion. In his renowned treatise on twining and tendril-bearing plants, Charles Darwin surmised that coiled tendrils serve as soft, springy attachments for the climbing plant. Yet, the true effect of the perverted helical shape of a coiled plant tendril has not been fully revealed. Using a combination of experiments on Cucurbitaceae tendrils, physical models constructed from strained rubber sheets, and numerical models of helical perversions, we have uncovered that tendril coiling occurs via anisotropic shrinkage of a strip of specialized cells in the interior of the tendril. Furthermore, variations in the mechanical behavior of tendrils as they become drier and ``woodier'' adds a new twist to the story of tendril coiling.

Silymarin Suppresses Cellular Inflammation By Inducing Reparative Stress Signaling.

PubMed

Lovelace, Erica S; Wagoner, Jessica; MacDonald, James; Bammler, Theo; Bruckner, Jacob; Brownell, Jessica; Beyer, Richard P; Zink, Erika M; Kim, Young-Mo; Kyle, Jennifer E; Webb-Robertson, Bobbie-Jo M; Waters, Katrina M; Metz, Thomas O; Farin, Federico; Oberlies, Nicholas H; Polyak, Stephen J

2015-08-28

Silymarin, a characterized extract of the seeds of milk thistle (Silybum marianum), suppresses cellular inflammation. To define how this occurs, transcriptional profiling, metabolomics, and signaling studies were performed in human liver and T cell lines. Cellular stress and metabolic pathways were modulated within 4 h of silymarin treatment: activation of Activating Transcription Factor 4 (ATF-4) and adenosine monophosphate protein kinase (AMPK) and inhibition of mammalian target of rapamycin (mTOR) signaling, the latter being associated with induction of DNA-damage-inducible transcript 4 (DDIT4). Metabolomics analyses revealed silymarin suppression of glycolytic, tricarboxylic acid (TCA) cycle, and amino acid metabolism. Anti-inflammatory effects arose with prolonged (i.e., 24 h) silymarin exposure, with suppression of multiple pro-inflammatory mRNAs and signaling pathways including nuclear factor kappa B (NF-κB) and forkhead box O (FOXO). Studies with murine knock out cells revealed that silymarin inhibition of both mTOR and NF-κB was partially AMPK dependent, whereas silymarin inhibition of mTOR required DDIT4. Other natural products induced similar stress responses, which correlated with their ability to suppress inflammation. Thus, natural products activate stress and repair responses that culminate in an anti-inflammatory cellular phenotype. Natural products like silymarin may be useful as tools to define how metabolic, stress, and repair pathways regulate cellular inflammation.

Silymarin Suppresses Cellular Inflammation By Inducing Reparative Stress Signaling

PubMed Central

Lovelace, Erica S.; Wagoner, Jessica; MacDonald, James; Bammler, Theo; Bruckner, Jacob; Brownell, Jessica; Beyer, Richard; Zink, Erika M.; Kim, Young-Mo; Kyle, Jennifer E.; Webb-Robertson, Bobbie-Jo; Waters, Katrina M.; Metz, Thomas O.; Farin, Federico; Oberlies, Nicholas H.; Polyak, Stephen J.

2016-01-01

Silymarin, a characterized extract of the seeds of milk thistle (Silybum marianum), suppresses cellular inflammation. To define how this occurs, transcriptional profiling, metabolomics, and signaling studies were performed in human liver and T cell lines. Cellular stress and metabolic pathways were modulated within 4 h of silymarin treatment: activation of Activating Transcription Factor 4 (ATF-4) and adenosine monophosphate protein kinase (AMPK) and inhibition of mammalian target of rapamycin (mTOR) signaling, the latter being associated with induction of DNA-damage-inducible transcript 4 (DDIT4). Metabolomics analyses revealed silymarin suppression of glycolytic, tricarboxylic acid (TCA) cycle, and amino acid metabolism. Anti-inflammatory effects arose with prolonged (i.e. 24 h) silymarin exposure, with suppression of multiple pro-inflammatory mRNAs and signaling pathways including nuclear factor kappa B (NF-κB) and forkhead box O (FOXO). Studies with murine knock out cells revealed that silymarin inhibition of both mTOR and NF-κB was partially AMPK dependent, while silymarin inhibition of mTOR required DDIT4. Other natural products induced similar stress responses, which correlated with their ability to suppress inflammation. Thus, natural products activate stress and repair responses that culminate in an anti-inflammatory cellular phenotype. Natural products like silymarin may be useful as tools to define how metabolic, stress, and repair pathways regulate cellular inflammation. PMID:26186142

Plant essential oils potency as natural antibiotic in Indonesian medicinal herb of “jamu”

NASA Astrophysics Data System (ADS)

Soetjipto, H.; Martono, Y.

2017-02-01

The main purposes of this study are to compile antibacterial activity data of essential oils from Indonesian’s plants in order which can be used as a natural antibiotic in “jamu” to increase potential Indonesian medicinal herb. By using Agar Diffusing method, Bioautography and Gas Chromatography Mass Spectrum, respectively, antibacterial activity and chemical compounds of 12 plants essential oils were studied in the Natural Product Chemistry Laboratory, Department of Chemistry, Faculty of Science and Mathematics, Satya Wacana Christian University, Salatiga since 2007 until 2015. The results of this studies showed that all of the essential oils have a medium to a strong antibacterial activity which are in the range of 30 - 2,500 μg and 80-5,000 μg. Further on, the essential oils analyzed by GCMS showed that each essential oils have different dominant compounds. These data can be used as basic doses in the usage of essential oils as natural antibiotics.

Succession Influences Wild Bees in a Temperate Forest Landscape: The Value of Early Successional Stages in Naturally Regenerated and Planted Forests

PubMed Central

Taki, Hisatomo; Okochi, Isamu; Okabe, Kimiko; Inoue, Takenari; Goto, Hideaki; Matsumura, Takeshi; Makino, Shun'ichi

2013-01-01

In many temperate terrestrial forest ecosystems, both natural human disturbances drive the reestablishment of forests. Succession in plant communities, in addition to reforestation following the creation of open sites through harvesting or natural disturbances, can affect forest faunal assemblages. Wild bees perform an important ecosystem function in human-altered and natural or seminatural ecosystems, as they are essential pollinators for both crops and wild flowering plants. To maintain high abundance and species richness for pollination services, it is important to conserve and create seminatural and natural land cover with optimal successional stages for wild bees. We examined the effects of forest succession on wild bees. In particular, we evaluated the importance of early successional stages for bees, which has been suspected but not previously demonstrated. A range of successional stages, between 1 and 178 years old, were examined in naturally regenerated and planted forests. In total 4465 wild bee individuals, representing 113 species, were captured. Results for total bees, solitary bees, and cleptoparasitic bees in both naturally regenerated and planted conifer forests indicated a higher abundance and species richness in the early successional stages. However, higher abundance and species richness of social bees in naturally regenerated forest were observed as the successional stages progressed, whereas the abundance of social bees in conifer planted forest showed a concave-shaped relationship when plotted. The results suggest that early successional stages of both naturally regenerated and conifer planted forest maintain a high abundance and species richness of solitary bees and their cleptoparasitic bees, although social bees respond differently in the early successional stages. This may imply that, in some cases, active forest stand management policies, such as the clear-cutting of planted forests for timber production, would create early successional

Succession influences wild bees in a temperate forest landscape: the value of early successional stages in naturally regenerated and planted forests.

PubMed

Taki, Hisatomo; Okochi, Isamu; Okabe, Kimiko; Inoue, Takenari; Goto, Hideaki; Matsumura, Takeshi; Makino, Shun'ichi

2013-01-01

In many temperate terrestrial forest ecosystems, both natural human disturbances drive the reestablishment of forests. Succession in plant communities, in addition to reforestation following the creation of open sites through harvesting or natural disturbances, can affect forest faunal assemblages. Wild bees perform an important ecosystem function in human-altered and natural or seminatural ecosystems, as they are essential pollinators for both crops and wild flowering plants. To maintain high abundance and species richness for pollination services, it is important to conserve and create seminatural and natural land cover with optimal successional stages for wild bees. We examined the effects of forest succession on wild bees. In particular, we evaluated the importance of early successional stages for bees, which has been suspected but not previously demonstrated. A range of successional stages, between 1 and 178 years old, were examined in naturally regenerated and planted forests. In total 4465 wild bee individuals, representing 113 species, were captured. Results for total bees, solitary bees, and cleptoparasitic bees in both naturally regenerated and planted conifer forests indicated a higher abundance and species richness in the early successional stages. However, higher abundance and species richness of social bees in naturally regenerated forest were observed as the successional stages progressed, whereas the abundance of social bees in conifer planted forest showed a concave-shaped relationship when plotted. The results suggest that early successional stages of both naturally regenerated and conifer planted forest maintain a high abundance and species richness of solitary bees and their cleptoparasitic bees, although social bees respond differently in the early successional stages. This may imply that, in some cases, active forest stand management policies, such as the clear-cutting of planted forests for timber production, would create early successional

Sesamin from Cuscuta palaestina natural plant extracts: Directions for new prospective applications.

PubMed

Abu-Lafi, Saleh; Makhamra, Sadam; Rayan, Ibrahim; Barriah, Waseim; Nasser, Ahmed; Abu Farkh, Basheer; Rayan, Anwar

2018-01-01

The aim of this study is to disclose the potential bioactive components of Cuscuta palaestina, a native parasitic natural plant of flora palaestina and to open direction towards new prospective application. GC-MS analysis identified 18 components in the methanolic extract of C. palaestina for the first time. The most appealing among them are Sesamin and two other phytosterols (Campesterol and Stigmasterol), all of which are documented in the scientific literature for their anticancer activity. Quantitation of Sesamin extracted from C. palaestina by HPLC-PDA with the use of three organic solvents showed that the Sesamin content in the methanolic extract was the highest. Following the disclosure of Sesamin presence in C. palaestina, we raised the question of whether it is produced naturally in C. palaestina or acquired from the host plant. The quantitation of Sesamin in C. palaestina was performed while being with five different host plants, and was compared with the amount of Sesamin in C. palaestina grown alone. The findings reveal that Sesamin is an endogenous secondary metabolite in C. palaestina. Thus, further studies are required to prove if C. palaestina can be used as an alternative source of anticancer phytochemicals, mainly Sesamin, and if proteins in the Sesamin production pathway could be valid biological targets for the development of novel and selective pesticides for control/ eradication of C. palaestina and maybe some other Cuscuta species. As well, the findings from this study raise a big question of whether inferring Sesamin production in C. palaestina could reduce its attack ability to host plants.

Sesamin from Cuscuta palaestina natural plant extracts: Directions for new prospective applications

PubMed Central

Abu-Lafi, Saleh; Makhamra, Sadam; Rayan, Ibrahim; Barriah, Waseim; Nasser, Ahmed; Abu Farkh, Basheer

2018-01-01

The aim of this study is to disclose the potential bioactive components of Cuscuta palaestina, a native parasitic natural plant of flora palaestina and to open direction towards new prospective application. GC-MS analysis identified 18 components in the methanolic extract of C. palaestina for the first time. The most appealing among them are Sesamin and two other phytosterols (Campesterol and Stigmasterol), all of which are documented in the scientific literature for their anticancer activity. Quantitation of Sesamin extracted from C. palaestina by HPLC-PDA with the use of three organic solvents showed that the Sesamin content in the methanolic extract was the highest. Following the disclosure of Sesamin presence in C. palaestina, we raised the question of whether it is produced naturally in C. palaestina or acquired from the host plant. The quantitation of Sesamin in C. palaestina was performed while being with five different host plants, and was compared with the amount of Sesamin in C. palaestina grown alone. The findings reveal that Sesamin is an endogenous secondary metabolite in C. palaestina. Thus, further studies are required to prove if C. palaestina can be used as an alternative source of anticancer phytochemicals, mainly Sesamin, and if proteins in the Sesamin production pathway could be valid biological targets for the development of novel and selective pesticides for control/ eradication of C. palaestina and maybe some other Cuscuta species. As well, the findings from this study raise a big question of whether inferring Sesamin production in C. palaestina could reduce its attack ability to host plants. PMID:29634770

Suppression of plant growth by nitrogen dioxide.

PubMed

Taylor, O C; Eaton, F M

1966-01-01

Nicotiana glutinosa and pinto bean seedlings (Phaseolus vulgaris) were exposed for short periods (3 days or less) to high concentrations of NO(2) (4.11-20.53 mg/m(3) to compare the resulting leaf lesions with ozone damage produced at concentrations of 0.43 to 0.86 mg/m(3). Although the same physiological age leaf tissue was damaged by both toxicants, damage caused by NO(2) was unlike that caused by ozone. Pinto bean (Phaseolus vulgaris) and Pearson improved tomato (Lycopersicon esculentum) seedlings were continuously exposed for 10 to 22 days, to low concentrations of NO(2) (less than 1.03 mg/m(3)). These exposures caused significant growth suppression, increase in green color (total chlorophyll content), and distortion of leaves.

[Research progress in chemical communication among insect-resistant genetically modified plants, insect pests and natural enemies].

PubMed

Liu, Qing-Song; Li, Yun-He; Chen, Xiu-Ping; Peng, Yu-Fa

2014-08-01

Semiochemicals released by plants or insects play an important role in the communication among plants, phytophagous insects and their natural enemies. They thus form a chemical information network which regulates intra- and inter-specific behaviors and sustains the composition and structure of plant and insect communities. The application of insect-resistant genetically modified (IRGM) crops may affect the chemical communication within and among the tritrophic levels, and thus cause disturbances to the biotic community structure and the stability of the farmland ecosystem. This has raised concerns about the environmental safety of IRGM crops and triggered research worldwide. In the current article we provided a brief summary of the chemical communication among plants, herbivores and natural enemies; analyzed the potential of IRGM crops to affect the chemical communication between plants and arthropods and the related mechanisms; and discussed the current research progress and the future prospects in this field. We hope that this will promote the research in this field by Chinese scientists and increase our understanding of the potential effects of growing of IRGM crops on the arthropod community structure.

Syringyl lignin is unaltered by severe sinapyl alcohol dehydrogenase suppression in tobacco.

PubMed

Barakate, Abdellah; Stephens, Jennifer; Goldie, Alison; Hunter, William N; Marshall, David; Hancock, Robert D; Lapierre, Catherine; Morreel, Kris; Boerjan, Wout; Halpin, Claire

2011-12-01

The manipulation of lignin could, in principle, facilitate efficient biofuel production from plant biomass. Despite intensive study of the lignin pathway, uncertainty exists about the enzyme catalyzing the last step in syringyl (S) monolignol biosynthesis, the reduction of sinapaldehyde to sinapyl alcohol. Traditional schemes of the pathway suggested that both guaiacyl (G) and S monolignols are produced by a single substrate-versatile enzyme, cinnamyl alcohol dehydrogenase (CAD). This was challenged by the discovery of a novel sinapyl alcohol dehydrogenase (SAD) that preferentially uses sinapaldehyde as a substrate and that was claimed to regulate S lignin biosynthesis in angiosperms. Consequently, most pathway schemes now show SAD (or SAD and CAD) at the sinapaldehyde reduction step, although functional evidence is lacking. We cloned SAD from tobacco (Nicotiana tabacum) and suppressed it in transgenic plants using RNA interference-inducing vectors. Characterization of lignin in the woody stems shows no change to content, composition, or structure, and S lignin is normal. By contrast, plants additionally suppressed in CAD have changes to lignin structure and S:G ratio and have increased sinapaldehyde in lignin, similar to plants suppressed in CAD alone. These data demonstrate that CAD, not SAD, is the enzyme responsible for S lignin biosynthesis in woody angiosperm xylem.

Characterization of the RNA silencing suppression activity of the Ebola virus VP35 protein in plants and mammalian cells.

PubMed

Zhu, Yali; Cherukuri, Nil Celebi; Jackel, Jamie N; Wu, Zetang; Crary, Monica; Buckley, Kenneth J; Bisaro, David M; Parris, Deborah S

2012-03-01

Ebola virus (EBOV) causes a lethal hemorrhagic fever for which there is no approved effective treatment or prevention strategy. EBOV VP35 is a virulence factor that blocks innate antiviral host responses, including the induction of and response to alpha/beta interferon. VP35 is also an RNA silencing suppressor (RSS). By inhibiting microRNA-directed silencing, mammalian virus RSSs have the capacity to alter the cellular environment to benefit replication. A reporter gene containing specific microRNA target sequences was used to demonstrate that prior expression of wild-type VP35 was able to block establishment of microRNA silencing in mammalian cells. In addition, wild-type VP35 C-terminal domain (CTD) protein fusions were shown to bind small interfering RNA (siRNA). Analysis of mutant proteins demonstrated that reporter activity in RSS assays did not correlate with their ability to antagonize double-stranded RNA (dsRNA)-activated protein kinase R (PKR) or bind siRNA. The results suggest that enhanced reporter activity in the presence of VP35 is a composite of nonspecific translational enhancement and silencing suppression. Moreover, most of the specific RSS activity in mammalian cells is RNA binding independent, consistent with VP35's proposed role in sequestering one or more silencing complex proteins. To examine RSS activity in a system without interferon, VP35 was tested in well-characterized plant silencing suppression assays. VP35 was shown to possess potent plant RSS activity, and the activities of mutant proteins correlated strongly, but not exclusively, with RNA binding ability. The results suggest the importance of VP35-protein interactions in blocking silencing in a system (mammalian) that cannot amplify dsRNA.

Factors associated with Leguminous Green Manure Incorporation and Fusarium wilt suppression in watermelon

USDA-ARS?s Scientific Manuscript database

A fall planted Vicia villosa cover crop incorporated in spring as a green manure can suppress Fusarium wilt [Fusarium oxysporum f. sp. niveum (FON)] of watermelon in Maryland and Delaware. Experiments were conducted to determine whether the mechanism of this suppression was general or specific, and ...

[Effects of plant viruses on vector and non-vector herbivorous arthropods and their natural enemies: a mini review].

PubMed

He, Xiao-Chan; Xu, Hong-Xing; Zhou, Xiao-Jun; Zheng, Xu-Song; Sun, Yu-Jian; Yang, Ya-Jun; Tian, Jun-Ce; Lü, Zhong-Xian

2014-05-01

Plant viruses transmitted by arthropods, as an important biotic factor, may not only directly affect the yield and quality of host plants, and development, physiological characteristics and ecological performances of their vector arthropods, but also directly or indirectly affect the non-vector herbivorous arthropods and their natural enemies in the same ecosystem, thereby causing influences to the whole agro-ecosystem. This paper reviewed the progress on the effects of plant viruses on herbivorous arthropods, including vector and non-vector, and their natural enemies, and on their ecological mechanisms to provide a reference for optimizing the management of vector and non-vector arthropod populations and sustainable control of plant viruses in agro-ecosystem.

Increasing leaf temperature reduces the suppression of isoprene emission by elevated CO₂ concentration.

PubMed

Potosnak, Mark J; Lestourgeon, Lauren; Nunez, Othon

2014-05-15

Including algorithms to account for the suppression of isoprene emission by elevated CO2 concentration affects estimates of global isoprene emission for future climate change scenarios. In this study, leaf-level measurements of isoprene emission were made to determine the short-term interactive effect of leaf temperature and CO2 concentration. For both greenhouse plants and plants grown under field conditions, the suppression of isoprene emission was reduced by increasing leaf temperature. For each of the four different tree species investigated, aspen (Populus tremuloides Michx.), cottonwood (Populus deltoides W. Bartram ex Marshall), red oak (Quercus rubra L.), and tundra dwarf willow (Salix pulchra Cham.), the suppression of isoprene by elevated CO2 was eliminated at increased temperature, and the maximum temperature where suppression was observed ranged from 25 to 35°C. Hypotheses proposed to explain the short-term suppression of isoprene emission by increased CO2 concentration were tested against this observation. Hypotheses related to cofactors in the methylerythritol phosphate (MEP) pathway were consistent with reduced suppression at elevated leaf temperature. Also, reduced solubility of CO2 with increased temperature can explain the reduced suppression for the phosphoenolpyruvate (PEP) carboxylase competition hypothesis. Some global models of isoprene emission include the short-term suppression effect, and should be modified to include the observed interaction. If these results are consistent at longer timescales, there are implications for predicting future global isoprene emission budgets and the reduced suppression at increased temperature could explain some of the variable responses observed in long-term CO2 exposure experiments. Copyright © 2014 Elsevier B.V. All rights reserved.

Indirect suppression of photosynthesis on individual leaves by arthropod herbivory

PubMed Central

Nabity, Paul D.; Zavala, Jorge A.; DeLucia, Evan H.

2009-01-01

Background Herbivory reduces leaf area, disrupts the function of leaves, and ultimately alters yield and productivity. Herbivore damage to foliage typically is assessed in the field by measuring the amount of leaf tissue removed and disrupted. This approach assumes the remaining tissues are unaltered, and plant photosynthesis and water balance function normally. However, recent application of thermal and fluorescent imaging technologies revealed that alterations to photosynthesis and transpiration propagate into remaining undamaged leaf tissue. Scope and Conclusions This review briefly examines the indirect effects of herbivory on photosynthesis, measured by gas exchange or chlorophyll fluorescence, and identifies four mechanisms contributing to the indirect suppression of photosynthesis in remaining leaf tissues: severed vasculature, altered sink demand, defence-induced autotoxicity, and defence-induced down-regulation of photosynthesis. We review the chlorophyll fluorescence and thermal imaging techniques used to gather layers of spatial data and discuss methods for compiling these layers to achieve greater insight into mechanisms contributing to the indirect suppression of photosynthesis. We also elaborate on a few herbivore-induced gene-regulating mechanisms which modulate photosynthesis and discuss the difficult nature of measuring spatial heterogeneity when combining fluorescence imaging and gas exchange technology. Although few studies have characterized herbivore-induced indirect effects on photosynthesis at the leaf level, an emerging literature suggests that the loss of photosynthetic capacity following herbivory may be greater than direct loss of photosynthetic tissues. Depending on the damage guild, ignoring the indirect suppression of photosynthesis by arthropods and other organisms may lead to an underestimate of their physiological and ecological impacts. PMID:18660492

Determining light requirements of groundcover plants from subtropical natural forest using hemispherical photography

NASA Astrophysics Data System (ADS)

Zhang, Yi; Zhong, Yonglin; Xu, Mingfeng; Su, Zhiyao

2017-01-01

In order to determine light requirements of indigenous groundcover plants for potential use in urban landscaping, we conducted a plant census in Yinpingshan Nature Reserve, Dongguan, China, and measured canopy structure and understory light regimes using hemispherical photography. We found that canopy openness, transmitted direct solar radiation, and transmitted diffuse solar radiation exhibited highly significant spatial heterogeneity. Species composition and diversity of groundcover plants were highly dependent on canopy structure and understory light condition. Greater diversity and more stems of groundcover plants were associated with greater canopy openness and understory radiation in most cases. Highly significant differences in species composition were detected along canopy openness, transmitted direct solar radiation, and transmitted diffuse solar radiation gradients, respectively. We also detected indicator species for specific understory light regimes, which will provide useful information when applying such species in urban greening under various light environments.

When suppressing one stereotype leads to rebound of another: on the procedural nature of stereotype rebound.

PubMed

Geeraert, Nicolas

2013-09-01

A known consequence of stereotype suppression is post-suppressional rebound (PSR), an ironic activation of the suppressed stereotype. This is typically explained as an unintended by-product from a dual-process model of mental control. Relying on this model, stereotype rebound is believed to be conceptual. Alternative accounts predict PSR to be featural or procedural. According to the latter account, stereotype rebound would not be limited to the suppressed social category, but could occur for a target from any social category. The occurrence of procedural stereotype rebound was examined across five experiments. Suppression of one particular stereotype consistently led to rebound for social targets belonging to the same or a different stereotype in an essay-writing task (Experiments 1-3) and led to facilitation in recognition of stereotype-consistent words (Experiment 4). Finally, stereotype suppression was shown to impact on assessments of stereotype use but not on heuristic thinking (Experiment 5).

Habitat Management to Suppress Pest Populations: Progress and Prospects.

PubMed

Gurr, Geoff M; Wratten, Steve D; Landis, Douglas A; You, Minsheng

2017-01-31

Habitat management involving manipulation of farmland vegetation can exert direct suppressive effects on pests and promote natural enemies. Advances in theory and practical techniques have allowed habitat management to become an important subdiscipline of pest management. Improved understanding of biodiversity-ecosystem function relationships means that researchers now have a firmer theoretical foundation on which to design habitat management strategies for pest suppression in agricultural systems, including landscape-scale effects. Supporting natural enemies with shelter, nectar, alternative prey/hosts, and pollen (SNAP) has emerged as a major research topic and applied tactic with field tests and adoption often preceded by rigorous laboratory experimentation. As a result, the promise of habitat management is increasingly being realized in the form of practical worldwide implementation. Uptake is facilitated by farmer participation in research and is made more likely by the simultaneous delivery of ecosystem services other than pest suppression.

Lime sulfur toxicity to broad mite, to its host plants and to natural enemies.

PubMed

Venzon, Madelaine; Oliveira, Rafael M; Perez, André L; Rodríguez-Cruz, Fredy A; Martins Filho, Sebastião

2013-06-01

An acaricidal effect of lime sulfur has not been demonstrated for Polyphagotarsonemus latus. However, lime sulfur can cause toxicity to natural enemies and to host plants. In this study, the toxicity of different concentrations of lime sulfur to P. latus, to the predatory mite Amblyseius herbicolus and to the predatory insect Chrysoperla externa was evaluated. Additionally, the phytotoxicity of lime sulfur to two P. latus hosts, chili pepper and physic nut plants, was determined. Lime sulfur at a concentration of 9.5 mL L(-1) restrained P. latus population growth. However, this concentration was deleterious to natural enemies. The predatory mite A. herbicolus showed a negative value of instantaneous growth rate, and only 50% of the tested larvae of C. externa reached adulthood when exposed to 10 mL L(-1) . Physic nut had severe injury symptoms when sprayed with all tested lime sulfur concentrations. For chili pepper plants, no phytoxicity was observed at any tested concentration. Lime sulfur might be used for P. latus control on chili pepper but not on physic nut owing to phytotoxicity. Care should be taken when using lime sulfur in view of negative effects on natural enemies. Selective lime sulfur concentration integrated with other management tactics may provide an effective and sustainable P. latus control on chili pepper. © 2012 Society of Chemical Industry.

Allelopathy relationship between plants and their use in organic farming

NASA Astrophysics Data System (ADS)

Marian, M.; Voşgan, Z.; Mare Roşca, O.; Mihalescu, L.

2017-05-01

Allelopathy is a process still little studied in the plant world, if we refer to the diversity of biochemical compounds, through which plants can interact with each other, with fungi or bacteria. Biochemical "dialogue" between organisms may have stimulatory or inhibitory effects, contributing to numerical setting of the populations, the assertion of some species over others, the establishment and strengthen of plant communities. Practically, the allelopathy can be exploited in organic farming in understanding and identifying compatibility between species, to finding natural substances with herbicide potential. In experiments conducted, diluted extracts of Taraxacum officinale and Cirsium vulgare strongly inhibited the germination and growth of corn and beans, while Hedera helix produced the same effect, but at higher concentrations of the extract. Humulus lupulus extract has a stimulating effect on the two species and it is possible to use as natural fertilizer. Extracts of Chenopodium album works as stimulator for Beta vulgaris, and potent inhibitor for Triticum aestivum. Agropyron repens is an aggressive competitor for Lycopersicon esculentum and Capsicum annuum, producing a strong inhibition. Juglans regia extracts and especially those of Satureja hortensis, can be used as natural herbicides for up delay germination and growth suppression for the species: Echinochloa crus-galli and Setaria glauca.

Suppression of cell wall-related genes associated with stunting of Oryza glaberrima infected with Rice tungro spherical virus

PubMed Central

Budot, Bernard O.; Encabo, Jaymee R.; Ambita, Israel Dave V.; Atienza-Grande, Genelou A.; Satoh, Kouji; Kondoh, Hiroaki; Ulat, Victor J.; Mauleon, Ramil; Kikuchi, Shoshi; Choi, Il-Ryong

2014-01-01

Rice tungro disease is a complex disease caused by the interaction between Rice tungro bacilliform virus and Rice tungro spherical virus (RTSV). RTSV alone does not cause recognizable symptoms in most Asian rice (Oryza sativa) plants, whereas some African rice (O. glaberrima) plants were found to become stunted by RTSV. Stunting of rice plants by virus infections usually accompanies the suppression of various cell wall-related genes. The expression of cell wall-related genes was examined in O. glaberrima and O. sativa infected with RTSV to see the relationship between the severity of stunting and the suppression of cell wall-related genes by RTSV. The heights of four accessions of O. glaberrima were found to decline by 14–34% at 28 days post-inoculation (dpi) with RTSV, whereas the height reduction of O. sativa plants by RTSV was not significant. RTSV accumulated more in O. glaberrima plants than in O. sativa plants, but the level of RTSV accumulation was not correlated with the degree of height reduction among the four accessions of O. glaberrima. Examination for expression of genes for cellulose synthase A5 (CESA5) and A6 (CESA6), cellulose synthase-like A9 (CSLA9) and C7, and α-expansin 1 (expansin 1) and 15 precursors in O. glaberrima and O. sativa plants between 7 and 28 dpi with RTSV showed that the genes such as those for CESA5, CESA6, CSLA9, and expansin 1were more significantly suppressed in stunted plants of O. glaberrima at 14 dpi with RTSV than in O. sativa, suggesting that stunting of O. glaberrima might be associated with these cell wall-related genes suppressed by RTSV. Examination for expression of these genes in O. sativa plants infected with other rice viruses in previous studies indicated that the suppression of the expansin 1 gene is likely to be a signature response commonly associated with virus-induced stunting of Oryza species. These results suggest that stunting of O. glaberrima by RTSV infection might be associated with the suppression

The impact of three recent coal-fired power plant closings on Pittsburgh air quality: A natural experiment.

PubMed

Russell, Marie C; Belle, Jessica H; Liu, Yang

2017-01-01

Relative to the rest of the United States, the region of southwestern Pennsylvania, including metropolitan Pittsburgh, experiences high ambient concentrations of fine particulate matter (PM 2.5 ), which is known to be associated with adverse respiratory and cardiovascular health impacts. This study evaluates whether the closing of three coal-fired power plants within the southwestern Pennsylvania region resulted in a significant decrease in PM 2.5 concentration. Both PM 2.5 data obtained from EPA ground stations in the study region and aerosol optical depth (AOD) data retrieved from the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments onboard the Terra and Aqua satellites were used to investigate regional air quality from January 2011 through December 2014. The impact of the plant closings on PM 2.5 concentration and AOD was evaluated using a series of generalized additive models. The model results show that monthly fuel consumption of the Elrama plant, which closed in October of 2012, and monthly fuel consumption of both the Mitchell and Hatfield's Ferry plants, which closed in October of 2013, were significant predictors of both PM 2.5 concentration and AOD at EPA ground stations in the study region, after controlling for multiple meteorological factors and long-term, region-wide air quality improvements. The model's power to predict PM 2.5 concentration increased from an adjusted R 2 of 0.61 to 0.68 after excluding data from ground stations with higher uncertainty due to recent increases in unconventional natural gas extraction activities. After preliminary analyses of mean PM 2.5 concentration and AOD showed a downward trend following each power plant shutdown, results from a series of generalized additive models confirmed that the activity of the three plants that closed, measured by monthly fuel consumption, was highly significant in predicting both AOD and PM 2.5 at 12 EPA ground stations; further research on PM 2.5 emissions from

Linearity assumption in soil-to-plant transfer factors of natural uranium and radium in Helianthus annuus L.

PubMed

Rodríguez, P Blanco; Tomé, F Vera; Fernández, M Pérez; Lozano, J C

2006-05-15

The linearity assumption of the validation of soil-to-plant transfer factors of natural uranium and (226)Ra was tested using Helianthus annuus L. (sunflower) grown in a hydroponic medium. Transfer of natural uranium and (226)Ra was tested in both the aerial fraction of plants and in the overall seedlings (roots and shoots). The results show that the linearity assumption can be considered valid in the hydroponic growth of sunflowers for the radionuclides studied. The ability of sunflowers to translocate uranium and (226)Ra was also investigated, as well as the feasibility of using sunflower plants to remove uranium and radium from contaminated water, and by extension, their potential for phytoextraction. In this sense, the removal percentages obtained for natural uranium and (226)Ra were 24% and 42%, respectively. Practically all the uranium is accumulated in the roots. However, 86% of the (226)Ra activity concentration in roots was translocated to the aerial part.

Production of virus resistant plants

DOEpatents

Dougherty, W.G.; Lindbo, J.A.

1996-12-10

A method of suppressing virus gene expression in plants using untranslatable plus sense RNA is disclosed. The method is useful for the production of plants that are resistant to virus infection. 9 figs.

RNAi trigger fragment truncation attenuates soybean FAD2-1 transcript suppression and yields intermediate oil phenotypes.

PubMed

Wagner, Nicholas; Mroczka, Andrew; Roberts, Peter D; Schreckengost, William; Voelker, Toni

2011-09-01

Suppression of the microsomal ω6 oleate desaturase during the seed development of soybean (Glycine max) with the 420-bp soybean FAD2-1A intron as RNAi trigger shifts the conventional fatty acid composition of soybean oil from 20% oleic and 60% polyunsaturates to one containing greater than 80% oleic acid and less than 10% polyunsaturates. To determine whether RNAi could be attenuated by reducing the trigger fragment length, transgenic plants were generated to express successively shorter 5' or 3' deletion derivatives of the FAD2-1A intron. We observed a gradual reduction in transcript suppression with shorter trigger fragments. Fatty acid composition was less affected with shorter triggers, and triggers less than 60 bp had no phenotypic effect. No trigger sequences conferring significantly higher or lower suppression efficiencies were found, and the primary determinant of suppression effect was sequence length. The observed relationship of transcript suppression with the induced fatty acid phenotype indicates that RNAi is a saturation process and not a step change between suppressed and nonsuppressed states and intermediate suppression states can be achieved. © 2010 Monsanto. Plant Biotechnology Journal © 2010 Society for Experimental Biology and Blackwell Publishing Ltd.

Performance of the Natural Mortality Factors of Aphis gossypii (Hemiptera: Aphididae) as a Function of Cotton Plant Variety and Phenology.

PubMed

Chamuene, António; Araújo, Tamíris Alves; Silva, Gerson; Costa, Thiago Leandro; Berger, Paulo Geraldo; Picanço, Marcelo Coutinho

2018-04-05

Natural mortality factors are responsible for regulating pest populations in the field. However, plant attributes such as the variety and phenological stage can influence the performance of these factors. Therefore, we investigated the performance of the natural mortality factors of Aphis gossypii (Glover; Hemiptera: Aphididae) as a function of the plant variety and phenology. To investigate the performance of these factors, we evaluated the mortality of A. gossypii caused by natural mortality factors for 2 yr in field conditions in transgenic (Bacillus thuringiensis/Roundup Ready) and non-transgenic cotton crops during vegetative, flowering, and fruiting stages. The natural mortality factors were affected similarly between the transgenic and non-transgenic plants; however, differences were observed in their performance, depending on the phenological stage of the cotton plant. Compared with other stages, predation was higher in the flowering stage, whereas the mortality caused by rainfall was higher in the vegetative stage. Coccinellid beetles were primarily responsible for the predation on A. gossypii. These findings highlight that the performance of the natural mortality factors of A. gossypii varied more as a function of the phenological stage of cotton than of the variety.

Syringyl Lignin Is Unaltered by Severe Sinapyl Alcohol Dehydrogenase Suppression in Tobacco[W

PubMed Central

Barakate, Abdellah; Stephens, Jennifer; Goldie, Alison; Hunter, William N.; Marshall, David; Hancock, Robert D.; Lapierre, Catherine; Morreel, Kris; Boerjan, Wout; Halpin, Claire

2011-01-01

The manipulation of lignin could, in principle, facilitate efficient biofuel production from plant biomass. Despite intensive study of the lignin pathway, uncertainty exists about the enzyme catalyzing the last step in syringyl (S) monolignol biosynthesis, the reduction of sinapaldehyde to sinapyl alcohol. Traditional schemes of the pathway suggested that both guaiacyl (G) and S monolignols are produced by a single substrate-versatile enzyme, cinnamyl alcohol dehydrogenase (CAD). This was challenged by the discovery of a novel sinapyl alcohol dehydrogenase (SAD) that preferentially uses sinapaldehyde as a substrate and that was claimed to regulate S lignin biosynthesis in angiosperms. Consequently, most pathway schemes now show SAD (or SAD and CAD) at the sinapaldehyde reduction step, although functional evidence is lacking. We cloned SAD from tobacco (Nicotiana tabacum) and suppressed it in transgenic plants using RNA interference–inducing vectors. Characterization of lignin in the woody stems shows no change to content, composition, or structure, and S lignin is normal. By contrast, plants additionally suppressed in CAD have changes to lignin structure and S:G ratio and have increased sinapaldehyde in lignin, similar to plants suppressed in CAD alone. These data demonstrate that CAD, not SAD, is the enzyme responsible for S lignin biosynthesis in woody angiosperm xylem. PMID:22158465

Modelling of plant-soil carbon, nitrogen and phosphorus cycling in semi-natural terrestrial ecosystems

NASA Astrophysics Data System (ADS)

Davies, Jessica; Quinton, John; Rowe, Ed; Tipping, Ed

2013-04-01

In recent centuries pools and fluxes of C, N and P in natural and semi-natural UK ecosystems have been transformed by atmospheric pollution leading to: acidification; eutrophication of surface waters; loss of biodiversity; and increased greenhouse gas emissions. In addition, climate change now threatens to perturb these systems further. Understanding in this field is vital in determining the consequences of artificial nutrient enrichment and land use and climate change, and mitigating against their effects. The N14CP model has been recently developed to assess the temporal responses of soil C, N and P pools to nutrient enrichment in semi-natural ecosystems, and explore the connections between these nutrients. It is a dynamic, mechanistic model, driven by: climate; CO2, N (fixation and pollutant deposition), and P (weathering and atmospheric deposition) inputs; and plant cover type. It explicitly links C, N, and P in both plants and soils, using plant element stoichiometry as the primary constraint. Net primary production, and plant/soil element pools, are calculated over time, and output fluxes of dissolved organic and inorganic, and gaseous, forms of C, N, and P produced. Radiocarbon data are used to constrain Soil Organic Matter (SOM) turnover. The SOM is represented as three pools, undergoing first-order decomposition reactions with turn-over rates ranging from 2 to 1000 years. The N14CP modelling methodology is discussed and its calibration and verification using observations from 200 northern European sites presented. Whilst the primary period of interest with respect to nutrient enrichment is from the industrial revolution onwards, plant-soil C, N and P are simulated at these sites for a period spanning from the start of the Holocene (to provide a spin-up period) to the present day. Clearly, during this time span land cover and usage will have changed at these sites, and histories of these changes are used as an input to the model. The influence of these land

The Role of Natural Enemy Foraging Guilds in Controlling Cereal Aphids in Michigan Wheat

PubMed Central

Safarzoda, Shahlo; Bahlai, Christine A.; Fox, Aaron F.; Landis, Douglas A.

2014-01-01

Insect natural enemies (predators and parasitoids) provide important ecosystem services by suppressing populations of insect pests in many agricultural crops. However, the role of natural enemies against cereal aphids in Michigan winter wheat (Triticum aestivum L.) is largely unknown. The objectives of this research were to characterize the natural enemy community in wheat fields and evaluate the role of different natural enemy foraging guilds (foliar-foraging versus ground-dwelling predators) in regulating cereal aphid population growth. We investigated these objectives during the spring and summer of 2012 and 2013 in four winter wheat fields on the Michigan State University campus farm in East Lansing, Michigan. We monitored and measured the impact of natural enemies by experimentally excluding or allowing their access to wheat plants infested with Rhopalosiphum padi (L.) and Sitobion avenae (F.) (Hemiptera: Aphidae). Our results indicate that the natural enemy community in the wheat fields consisted mostly of foliar-foraging and ground-dwelling predators with relatively few parasitoids. In combination, these natural enemy groups were very effective at reducing cereal aphid populations. We also investigated the role of each natural enemy foraging guild (foliar-foraging versus ground-dwelling predators) independently. Overall, our results suggest that, in combination, natural enemies can almost completely halt early-season aphid population increase. Independently, ground-dwelling predators were more effective at suppressing cereal aphid populations than foliar-foraging predators under the conditions we studied. Our results differ from studies in Europe and the US Great Plains where foliar foraging predators and parasitoids are frequently more important cereal aphid natural enemies. PMID:25473951

Gathering "tea"--from necessity to connectedness with nature. Local knowledge about wild plant gathering in the Biosphere Reserve Grosses Walsertal (Austria).

PubMed

Grasser, Susanne; Schunko, Christoph; Vogl, Christian R

2012-08-13

Wild plant gathering is an essential element in livelihood strategies all over the world. However due to changing circumstances in Europe, the reason for gathering has altered from one of necessity in the past to a pleasurable activity today. Wild plant gathering has therefore also received renewed attention as a form of intangible cultural heritage expressing local preferences, habits and man's relationship with nature. In the Biosphere Reserve Grosses Walsertal (Austria), local people's knowledge of the gathering of wild plants and their perception of their own gathering activities are being documented. The focus of this paper is on the uses of herbal teas and the informal guidelines for gathering plants that have been issued by the Bergtee (mountain tea) association. Thirty-six free-list interviews were conducted with subsequent semi-structured interviews and three focus group meetings held with members of the Bergtee association. Participatory observation (gathering and processing plants, mixing and marketing tea) also allowed for greater understanding of what had been reported. In total, 140 different gathered plant species were listed by respondents. Herbal tea is the most frequently mentioned use. The Bergtee association, founded by a young man and two middle-aged women in the valley, is a good example of the link between biological and cultural diversity, with the aim of sharing the biosphere reserve's natural treasures as well as local plant-related knowledge in the form of herbal tea products. The association's informal guidelines for gathering reflect people's attitude to nature: monetary income does not play a major role in gathering plants; instead people's appreciation of the value of the nature around them is to the fore. Gathering wild plants can be seen as an expression of people's regional identity. The conscious appreciation of nature and related local knowledge is crucial for the sustainable conservation and use of the Biosphere Reserve

RNA-Seq effectively monitors gene expression in Eutrema salsugineum plants growing in an extreme natural habitat and in controlled growth cabinet conditions

PubMed Central

2013-01-01

Background The investigation of extremophile plant species growing in their natural environment offers certain advantages, chiefly that plants adapted to severe habitats have a repertoire of stress tolerance genes that are regulated to maximize plant performance under physiologically challenging conditions. Accordingly, transcriptome sequencing offers a powerful approach to address questions concerning the influence of natural habitat on the physiology of an organism. We used RNA sequencing of Eutrema salsugineum, an extremophile relative of Arabidopsis thaliana, to investigate the extent to which genetic variation and controlled versus natural environments contribute to differences between transcript profiles. Results Using 10 million cDNA reads, we compared transcriptomes from two natural Eutrema accessions (originating from Yukon Territory, Canada and Shandong Province, China) grown under controlled conditions in cabinets and those from Yukon plants collected at a Yukon field site. We assessed the genetic heterogeneity between individuals using single-nucleotide polymorphisms (SNPs) and the expression patterns of 27,016 genes. Over 39,000 SNPs distinguish the Yukon from the Shandong accessions but only 4,475 SNPs differentiated transcriptomes of Yukon field plants from an inbred Yukon line. We found 2,989 genes that were differentially expressed between the three sample groups and multivariate statistical analyses showed that transcriptomes of individual plants from a Yukon field site were as reproducible as those from inbred plants grown under controlled conditions. Predicted functions based upon gene ontology classifications show that the transcriptomes of field plants were enriched by the differential expression of light- and stress-related genes, an observation consistent with the habitat where the plants were found. Conclusion Our expectation that comparative RNA-Seq analysis of transcriptomes from plants originating in natural habitats would be confounded

Overexpression of the PAP1 Transcription Factor Reveals a Complex Regulation of Flavonoid and Phenylpropanoid Metabolism in Nicotiana tabacum Plants Attacked by Spodoptera litura

PubMed Central

Mitsunami, Tomoko; Nishihara, Masahiro; Galis, Ivan; Alamgir, Kabir Md; Hojo, Yuko; Fujita, Kohei; Sasaki, Nobuhiro; Nemoto, Keichiro; Sawasaki, Tatsuya; Arimura, Gen-ichiro

2014-01-01

Anthocyanin pigments and associated flavonoids have demonstrated antioxidant properties and benefits for human health. Consequently, current plant bioengineers have focused on how to modify flavonoid metabolism in plants. Most of that research, however, does not consider the role of natural biotic stresses (e.g., herbivore attack). To understand the influence of herbivore attack on the metabolic engineering of flavonoids, we examined tobacco plants overexpressing the Arabidopsis PAP1 gene (encoding an MYB transcription factor), which accumulated anthocyanin pigments and other flavonoids/phenylpropanoids. In comparison to wild-type and control plants, transgenic plants exhibited greater resistance to Spodoptera litura. Moreover, herbivory suppressed the PAP1-induced increase of transcripts of flavonoid/phenylpropanoid biosynthetic genes (e.g., F3H) and the subsequent accumulation of these genes' metabolites, despite the unaltered PAP1 mRNA levels after herbivory. The instances of down-regulation were independent of the signaling pathways mediated by defense-related jasmonates but were relevant to the levels of PAP1-induced and herbivory-suppressed transcription factors, An1a and An1b. Although initially F3H transcripts were suppressed by herbivory, after the S. litura feeding was interrupted, F3H transcripts increased. We hypothesize that in transgenic plants responding to herbivory, there is a complex mechanism regulating enriched flavonoid/phenylpropanoid compounds, via biotic stress signals. PMID:25268129

Potential synergistic effects of cereal rye biomass and soybean planting density on weed suppression

USDA-ARS?s Scientific Manuscript database

Increasing crop density is a cultural weed management practice that can complement the use of cover crops for weed suppression. In this research, we created a range of cover crop biomass and soybean densities in order to assess their weed suppressive ability alone and in combination. The experiment ...

Plant and Insect Viruses in Managed and Natural Environments: Novel and Neglected Transmission Pathways.

PubMed

Jones, Roger A C

2018-01-01

The capacity to spread by diverse transmission pathways enhances a virus' ability to spread effectively and survive when circumstances change. This review aims to improve understanding of how plant and insect viruses spread through natural and managed environments by drawing attention to 12 novel or neglected virus transmission pathways whose contribution is underestimated. For plant viruses, the pathways reviewed are vertical and horizontal transmission via pollen, and horizontal transmission by parasitic plants, natural root grafts, wind-mediated contact, chewing insects, and contaminated water or soil. For insect viruses, they are transmission by plants serving as passive "vectors," arthropod vectors, and contamination of pollen and nectar. Based on current understanding of the spatiotemporal dynamics of virus spread, the likely roles of each pathway in creating new primary infection foci, enlarging previously existing infection foci, and promoting generalized virus spread are estimated. All pathways except transmission via parasitic plants, root grafts, and wind-mediated contact transmission are likely to produce new primary infection foci. All 12 pathways have the capability to enlarge existing infection foci, but only to a limited extent when spread occurs via virus-contaminated soil or vertical pollen transmission. All pathways except those via parasitic plant, root graft, contaminated soil, and vertical pollen transmission likely contribute to generalized virus spread, but to different extents. For worst-case scenarios, where mixed populations of host species occur under optimal virus spread conditions, the risk that host species jumps or virus emergence events will arise is estimated to be "high" for all four insect virus pathways considered, and, "very high" or "moderate" for plant viruses transmitted by parasitic plant and root graft pathways, respectively. To establish full understanding of virus spread and thereby optimize effective virus disease

Synthetic mimicking of plant oils and comparison with naturally grown products in polyurethane synthesis.

PubMed

Coles, Stuart R; Barker, Guy; Clark, Andrew J; Kirwan, Kerry; Jacobs, Daniel; Makenji, Kylash; Pink, David

2008-06-11

The use of plant oils as industrial feedstocks can often be hampered by their lack of optimization towards a particular process, as well as their development being risky; growing suitable volumes of crops to test can take up to five years. To circumvent this, we aimed to discover a method that would mimic plant oil profiles in the laboratory, and show that they exhibited similar properties to the naturally grown plant oils in a given process. Using the synthesis of polyurethanes as an example, we have synthesized six different polymers and demonstrated that plant oils will produce polymers with similar physical properties to those oils mimicked in the laboratory. The use of this mimicking process can be extended to other types of polymers to obtain a method for predicting the properties of a given material based on the plant oil composition of a crop before it is grown in bulk.

Production of red-flowered plants by genetic engineering of multiple flavonoid biosynthetic genes.

PubMed

Nakatsuka, Takashi; Abe, Yoshiko; Kakizaki, Yuko; Yamamura, Saburo; Nishihara, Masahiro

2007-11-01

Orange- to red-colored flowers are difficult to produce by conventional breeding techniques in some floricultural plants. This is due to the deficiency in the formation of pelargonidin, which confers orange to red colors, in their flowers. Previous researchers have reported that brick-red colored flowers can be produced by introducing a foreign dihydroflavonol 4-reductase (DFR) with different substrate specificity in Petunia hybrida, which does not accumulate pelargonidin pigments naturally. However, because these experiments used dihydrokaempferol (DHK)-accumulated mutants as transformation hosts, this strategy cannot be applied directly to other floricultural plants. Thus in this study, we attempted to produce red-flowered plants by suppressing two endogenous genes and expressing one foreign gene using tobacco as a model plant. We used a chimeric RNAi construct for suppression of two genes (flavonol synthase [FLS] and flavonoid 3'-hydroxylase [F3'H]) and expression of the gerbera DFR gene in order to accumulate pelargonidin pigments in tobacco flowers. We successfully produced red-flowered tobacco plants containing high amounts of additional pelargonidin as confirmed by HPLC analysis. The flavonol content was reduced in the transgenic plants as expected, although complete inhibition was not achieved. Expression analysis also showed that reduction of the two-targeted genes and expression of the foreign gene occurred simultaneously. These results demonstrate that flower color modification can be achieved by multiple gene regulation without use of mutants if the vector constructs are designed resourcefully.

Plant species composition alters the sign and strength of an emergent multi-predator effect by modifying predator foraging behaviour.

PubMed

Wilby, Andrew; Anglin, Linda Anderson; Nesbit, Christopher M

2013-01-01

The prediction of pest-control functioning by multi-predator communities is hindered by the non-additive nature of species functioning. Such non-additivity, commonly termed an emergent multi-predator effect, is known to be affected by elements of the ecological context, such as the structure and composition of vegetation, in addition to the traits of the predators themselves. Here we report mesocosm experiments designed to test the influence of plant density and species composition (wheat monoculture or wheat and faba bean polyculture) on the emergence of multi-predator effects between Adalia bipunctata and Chrysoperla carnea, in their suppression of populations of the aphid Metopolophium dirhodum. The mesocosm experiments were followed by a series of behavioural observations designed to identify how interactions among predators are modified by plant species composition and whether these effects are consistent with the observed influence of plant species composition on aphid population suppression. Although plant density was shown to have no influence on the multi-predator effect on aphid population growth, plant composition had a marked effect. In wheat monoculture, Adalia and Chrysoperla mixed treatments caused greater suppression of M. dirhodum populations than expected. However this positive emergent effect was reversed to a negative multi-predator effect in wheat and faba bean polyculture. The behavioural observations revealed that although dominant individuals did not respond to the presence of faba bean plants, the behaviour of sub-dominants was affected markedly, consistent with their foraging for extra-floral nectar produced by the faba bean. This interaction between plant composition and predator community composition on the foraging behaviour of sub-dominants is thought to underlie the observed effect of plant composition on the multi-predator effect. Thus, the emergence of multi-predator effects is shown to be strongly influenced by plant species

Planted and natural tree seedling survival and density in three floodplain restorations on abandoned agricultural fields

Treesearch

Allen E. Plocher

2003-01-01

In three floodplain forest restorations, established in abandoned agricultural fields in Illinois, permanent plots were sampled for 3 years to determine survivorship and density of planted tree seedlings, and species composition and density of natural regeneration. Planted tree survivorship decreased over time at all sites and after 3 years ranged from 32 to 61 percent...

The cost of carbon capture and storage for natural gas combined cycle power plants.

PubMed

Rubin, Edward S; Zhai, Haibo

2012-03-20

This paper examines the cost of CO(2) capture and storage (CCS) for natural gas combined cycle (NGCC) power plants. Existing studies employ a broad range of assumptions and lack a consistent costing method. This study takes a more systematic approach to analyze plants with an amine-based postcombustion CCS system with 90% CO(2) capture. We employ sensitivity analyses together with a probabilistic analysis to quantify costs for plants with and without CCS under uncertainty or variability in key parameters. Results for new baseload plants indicate a likely increase in levelized cost of electricity (LCOE) of $20-32/MWh (constant 2007$) or $22-40/MWh in current dollars. A risk premium for plants with CCS increases these ranges to $23-39/MWh and $25-46/MWh, respectively. Based on current cost estimates, our analysis further shows that a policy to encourage CCS at new NGCC plants via an emission tax or carbon price requires (at 95% confidence) a price of at least $125/t CO(2) to ensure NGCC-CCS is cheaper than a plant without CCS. Higher costs are found for nonbaseload plants and CCS retrofits.

Assessment of soil contamination by (210)Po and (210)Pb around heavy oil and natural gas fired power plants.

PubMed

Al-Masri, M S; Haddad, Kh; Doubal, A W; Awad, I; Al-Khatib, Y

2014-06-01

Soil contamination by (210)Pb and (210)Po around heavy oil and natural gas power plants has been investigated; fly and bottom ash containing enhanced levels of (210)Pb and (210)Po were found to be the main source of surface soil contamination. The results showed that (210)Pb and (210)Po in fly-ash (economizer, superheater) is highly enriched with (210)Pb and (210)Po, while bottom-ash (boiler) is depleted. The highest (210)Pb and (210)Po activity concentrations were found to be in economizer ash, whereas the lowest activity concentration was in the recirculator ash. On the other hand, (210)Pb and (210)Po activity concentrations in soil samples were found to be higher inside the plant site area than those samples collected from surrounding areas. The highest levels were found in the vicinity of Mhardeh and Tishreen power plants; both plants are operated by heavy oil and natural fuels, while the lowest values were found to be in those samples collected from Nasrieh power plant, which is only operated by one type of fuel, viz. natural gas. In addition, the levels of surface soil contamination have decreased as the distance from the power plant site center increased. Copyright © 2014 Elsevier Ltd. All rights reserved.

The environmental geochemistry of trace elements and naturally radionuclides in a coal gangue brick-making plant.

PubMed

Zhou, Chuncai; Liu, Guijian; Cheng, Siwei; Fang, Ting; Lam, Paul K S

2014-08-28

An investigation focused on the transformation and distribution behaviors of trace elements and natural radionuclides around a coal gangue brick plant was conducted. Simultaneous sampling of coal gangue, brick, fly ash and flue gas were implemented. Soil, soybean and earthworm samples around the brick plant were also collected for comprehensive ecological assessment. During the firing process, trace elements were released and redistributed in the brick, fly ash and the flue gas. Elements can be divided into two groups according to their releasing characteristics, high volatile elements (release ratio higher than 30%) are represented by Cd, Cu, Hg, Pb, Se and Sn, which emitted mainly in flue gas that would travel and deposit at the northeast and southwest direction around the brick plant. Cadmium, Ni and Pb are bio-accumulated in the soybean grown on the study area, which indicates potential health impacts in case of human consumption. The high activity of natural radionuclides in the atmosphere around the plant as well as in the made-up bricks will increase the health risk of respiratory system.

The Environmental Geochemistry of Trace Elements and Naturally Radionuclides in a Coal Gangue Brick-Making Plant

PubMed Central

Zhou, Chuncai; Liu, Guijian; Cheng, Siwei; Fang, Ting; Lam, Paul K. S.

2014-01-01

An investigation focused on the transformation and distribution behaviors of trace elements and natural radionuclides around a coal gangue brick plant was conducted. Simultaneous sampling of coal gangue, brick, fly ash and flue gas were implemented. Soil, soybean and earthworm samples around the brick plant were also collected for comprehensive ecological assessment. During the firing process, trace elements were released and redistributed in the brick, fly ash and the flue gas. Elements can be divided into two groups according to their releasing characteristics, high volatile elements (release ratio higher than 30%) are represented by Cd, Cu, Hg, Pb, Se and Sn, which emitted mainly in flue gas that would travel and deposit at the northeast and southwest direction around the brick plant. Cadmium, Ni and Pb are bio-accumulated in the soybean grown on the study area, which indicates potential health impacts in case of human consumption. The high activity of natural radionuclides in the atmosphere around the plant as well as in the made-up bricks will increase the health risk of respiratory system. PMID:25164252

Weed suppression by grasses for orchard floor management

USDA-ARS?s Scientific Manuscript database

Fruit trees in orchards of the mid-Atlantic region are often planted in vegetation-free rows alternating with grass travel alleys. The tree rows can be maintained vegetation-free by herbicides or tillage but soil degradation or tree injury can result from these practices. Grasses that suppress wee...

An Automated High-Throughput System to Fractionate Plant Natural Products for Drug Discovery

PubMed Central

Tu, Ying; Jeffries, Cynthia; Ruan, Hong; Nelson, Cynthia; Smithson, David; Shelat, Anang A.; Brown, Kristin M.; Li, Xing-Cong; Hester, John P.; Smillie, Troy; Khan, Ikhlas A.; Walker, Larry; Guy, Kip; Yan, Bing

2010-01-01

The development of an automated, high-throughput fractionation procedure to prepare and analyze natural product libraries for drug discovery screening is described. Natural products obtained from plant materials worldwide were extracted and first prefractionated on polyamide solid-phase extraction cartridges to remove polyphenols, followed by high-throughput automated fractionation, drying, weighing, and reformatting for screening and storage. The analysis of fractions with UPLC coupled with MS, PDA and ELSD detectors provides information that facilitates characterization of compounds in active fractions. Screening of a portion of fractions yielded multiple assay-specific hits in several high-throughput cellular screening assays. This procedure modernizes the traditional natural product fractionation paradigm by seamlessly integrating automation, informatics, and multimodal analytical interrogation capabilities. PMID:20232897

Occupational exposure to natural radioactivity in a zircon sand milling plant.

PubMed

Ballesteros, Luisa; Zarza, Isidoro; Ortiz, Josefina; Serradell, Vicente

2008-10-01

Raw zirconium sand is one of the substances (naturally occurring radioactive material, NORM) which is widely used in the ceramic industry. This sand contains varying concentrations of natural radionuclides: mostly U-238 but also Th-232 and U-235, together with their daughters, and therefore may need to be regulated by Directive 96/29/EURATOM. This paper describes the method used to perform the radiological study on a zircon sand milling plant and presents the results obtained. Internal and external doses were evaluated using radioactivity readings from sand, airborne dust, intermediate materials and end products. The results on total effective dose show the need for this type of industry to be carefully controlled, since values near to 1 mSv were obtained.

Fitness consequences of occasional outcrossing in a functionally asexual plant (Oenothera biennis).

PubMed

Maron, John L; Johnson, Marc T J; Hastings, Amy P; Agrawal, Anurag A

2018-02-01

Many clonal organisms occasionally outcross, but the long-term consequences of such infrequent events are often unknown. During five years, representing three to five plant generations, we followed 16 experimental field populations of the forb, Oenothera biennis, originally planted with the same 18 original genotypes. Oenothera biennis usually self fertilizes, which, due to its genetic system (permanent translocation heterozygosity), results in seeds that are clones of the maternal plant. However, rare outcrossing produces genetically novel offspring (but without recombination or increased heterozygosity). We sought to understand whether novel genotypes produced through natural outcrossing had greater fecundity or different multigenerational dynamics compared to our original genotypes. We further assessed whether any differences in fitness or abundances through time between original and novel genotypes were exaggerated in the presence vs. absence of insect herbivores. Over the course of the experiment, we genotyped >12,500 plants using microsatellite DNA markers to identify and track the frequency of specific genotypes and estimated fecundity on a subset (>3,000) of plants. The effective outcrossing rate was 7.3% in the first year and ultimately 50% of the plants were of outcrossed origin by the final year of the experiment. Lifetime fruit production per plant was on average 32% higher across all novel genotypes produced via outcrossing compared to the original genotypes, and this fecundity advantage was significantly enhanced in populations lacking herbivores. Among 43 novel genotypes that were abundant enough to phenotype with replication, plants produced nearly 30% more fruits than the average of their specific two parental genotypes, and marginally more fruits (8%) than their most fecund parent. Mean per capita fecundity of novel genotypes predicted their relative frequencies at the end of the experiment. Novel genotypes increased more dramatically in

The nature of the near-infrared interline sky background using fibre Bragg grating OH suppression

NASA Astrophysics Data System (ADS)

Trinh, Christopher Q.; Ellis, Simon C.; Bland-Hawthorn, Joss; Horton, Anthony J.; Lawrence, Jon S.; Leon-Saval, Sergio G.

2013-07-01

We analyse the near-infrared interline sky background, OH and O2 emission in 19 h of H-band observations with the GNOSIS OH-suppression unit and the IRIS2 spectrograph at the 3.9-m Anglo-Australian Telescope. We find that the long-term behaviour of OH emission is best described by a gradual decrease during the first half of the night followed by a gradual increase during the second half of the night following the behaviour of the solar elevation angle. We measure the interline background at 1.520 μm where the instrumental thermal background is very low and study its variation with zenith distance, time after sunset, ecliptic latitude, lunar zenith distance and lunar distance to determine the presence of non-thermal atmospheric emission, zodiacal scattered light and scattered moonlight. Zodiacal scattered light is too faint to be detected in the summed observations. Scattered moonlight due to Mie scattering by atmospheric aerosols is seen at small lunar distances (ρ ≲ 11°), but is otherwise too faint to detect. Except at very small lunar distances the interline background at a resolving power of R ≈ 2400 when using OH-suppression fibres is dominated by a non-thermal atmospheric source with a temporal behaviour that resembles atmospheric OH emission, suggesting that the interline background contains instrumentally scattered OH. However, the interline background dims more rapidly than OH early in the night, suggesting contributions from rapid dimming molecules. The absolute interline background is 560 ± 120 photons s-1 m-2 μm- 1 arcsec-2 under dark conditions. This value is similar to previous measurements without OH suppression, suggesting that non-suppressed atmospheric emission is responsible for the interline background level. Future OH-suppression fibre designs may address this by the suppression of more sky lines using more accurate sky-line measurements taken from high-resolution spectra.

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.

[Sugar Chain Construction of Functional Natural Products Using Plant Glucosyltransferases].

PubMed

Mizukami, Hajime

2015-01-01

Plant secondary product glycosyltransferases belong to family 1 of the glycosyltransferase superfamily and mediate the transfer of a glycosyl residue from activated nucleotide sugars to lipophilic small molecules, thus affecting the solubility, stability and pharmacological activities of the sugar-accepting compounds. The biotechnological application of plant glycosyltransferases in glycoside synthesis has attracted attention because enzymatic glycosylation offers several advantages over chemical methods, including (1) avoiding the use of harsh conditions and toxic catalysts, (2) providing strict control of regio-and stereo-selectivity and (3) high efficiency. This review describes the in vivo and in vitro glycosylation of natural organic compounds using glycosyltransferases, focusing on our investigation of enzymatic synthesis of curcumin glycosides. Our current efforts toward functional characterization of some glycosyltransferases involved in the biosynthesis of iridoids and crocin, as well as in the sugar chain elongation of quercetin glucosides, are described. Finally, I describe the relationship of the structure of sugar chains and the intestinal absorption which was investigated using chemoenzymatically synthesized quercetin glycosides.

Suppression of Metastasis by Primary Tumor and Acceleration of Metastasis Following Primary Tumor Resection: A Natural Law?

PubMed

Hanin, Leonid; Rose, Jason

2018-03-01

We study metastatic cancer progression through an extremely general individual-patient mathematical model that is rooted in the contemporary understanding of the underlying biomedical processes yet is essentially free of specific biological assumptions of mechanistic nature. The model accounts for primary tumor growth and resection, shedding of metastases off the primary tumor and their selection, dormancy and growth in a given secondary site. However, functional parameters descriptive of these processes are assumed to be essentially arbitrary. In spite of such generality, the model allows for computing the distribution of site-specific sizes of detectable metastases in closed form. Under the assumption of exponential growth of metastases before and after primary tumor resection, we showed that, regardless of other model parameters and for every set of site-specific volumes of detected metastases, the model-based likelihood-maximizing scenario is always the same: complete suppression of metastatic growth before primary tumor resection followed by an abrupt growth acceleration after surgery. This scenario is commonly observed in clinical practice and is supported by a wealth of experimental and clinical studies conducted over the last 110 years. Furthermore, several biological mechanisms have been identified that could bring about suppression of metastasis by the primary tumor and accelerated vascularization and growth of metastases after primary tumor resection. To the best of our knowledge, the methodology for uncovering general biomedical principles developed in this work is new.

Weed suppression by grasses for orchard floor management

USDA-ARS?s Scientific Manuscript database

Fruit trees in orchards of the mid-Atlantic region of the U.S. are often planted in vegetation-free rows alternating with grass travel alleys. The tree rows can be maintained vegetation-free by herbicides or tillage, but soil degradation or tree injury can result. Grass that is managed to suppress...

Evaluation of plant-based natural coagulants for municipal wastewater treatment.

PubMed

Maurya, Sandhya; Daverey, Achlesh

2018-01-01

In this study, four plant-based natural coagulants (banana peel powder, banana stem juice, papaya seed powder and neem leaf powder) were evaluated for the removal of turbidity, chemical oxygen demand (COD) and total suspended solids (TSS) from municipal wastewater. The experiments were conducted at room temperature without adjusting the initial pH. The maximum turbidity removal was observed with banana peel powder (59.6%) at 0.4 g/L of dosage. Papaya seed powder and banana stem juice were the most effective for TSS removal (66.66%) and COD removal (66.67%), respectively. Significant linear relationships between turbidity and TSS ( R 2  = 0.67-0.88) and turbidity removals and COD removals ( R 2  = 0.68-0.8) were observed. Interestingly, all the natural coagulants tested in the study did not change the pH of the wastewater, which is an added advantage. FTIR analysis of banana peels revealed that functional groups such as carboxylic acid, hydroxyl and aliphatic amines might be responsible for promoting the coagulation-flocculation by neutralizing the charge on impurities in water. Overall, the results suggest the potential of low-cost natural coagulants in municipal wastewater treatment.

Polychlorinated biphenyls and polybrominated diphenylethers in soils from planted forests and adjacent natural forests on a tropical island.

PubMed

Liu, Xin; Wang, Shuai; Jiang, Yishan; Sun, Yingtao; Li, Jun; Zhang, Gan

2017-08-01

Transformation from natural forests to planted forests in tropical regions is an expanding global phenomenon causing major modifications of land cover and soil properties, e.g. soil organic carbon (SOC). This study investigated accumulations of POPs in soils under eucalyptus and rubber forests as compared with adjacent natural forests on Hainan Island, China. Results showed that due to the greater forest filter effect and the higher SOC, the natural forest have accumulated larger amounts of POPs in the top 20 cm soil. Based on correlation and air-soil equilibrium analysis, we highlighted the importance of SOC in the distribution of POPs. It is assumed that the elevated mobility of POPs in the planted forests was caused by greater loss of SOC and extensive leaching in the soil profile. This suggests that a better understanding of global POPs fate should take into consideration the role of planted forests. Copyright © 2017 Elsevier Ltd. All rights reserved.

Suppression of Native Soil Organic Matter Decomposition by Post-Fermentation Sludge in Agriculture Soil as Assessed by 13C Natural Abundance

NASA Astrophysics Data System (ADS)

Stelmach, W.; Bieganowski, A.; Kuzyakov, Y.

2016-12-01

Anaerobic digestion of organic wastes results in the production of biogas and post-fermentation sludge. Post-fermentation sludge, which is rich in nutrients and contains more easily accessible inorganic-N than comparable composts, can be used as an alternative fertilizer in organic agriculture systems. While the effects of post fermentation sludge application on crop health and productivity have been extensively studied, little is known about its effects on soil parameters and long-term soil health. Thus, the main aim of this study was to determine the effects of post-fermentation sludge fertilization on agriculture soil quality. Specifically, it examined the efficiency and sequence of sludge utilisation by microorganisms and its influence on the utilisation/stabilization of native soil organic matter (SOM).To determine changes in SOM turnover after the addition of sludge, we utilized a natural stable carbon isotope labelling approach. Sludge produced from C4 plant residues (e.g. maize) was applied to soil under C3 cropping, resulting in distinct stable isotope signatures of fertilizer and SOM. Measuring the carbon isotope composition of CO2 produced in this microcosm experiment permitted accurate determination of the proportion of CO2 fluxes arising from both C sources. The addition of post-fermentation sludge increased the CO2 emissions from the soil by 30%. δ13C analysis of the total CO2 efflux revealed that post-fermentation sludge decreased SOM decomposition by 42% compared to control. Only 34% of the post-fermentation sludge had been mineralized after two months of incubation in the soil.The collective results of our study reveal that application of post-fermentation sludge suppresses SOM decomposition, suggesting its use as a fertilizer could positively influence long-term soil quality. Finally, the success of the natural abundance microcosm labeling approach in our study supports its use as an effective method of analyzing the effects of various

Natural genetic and induced plant resistance, as a control strategy to plant-parasitic nematodes alternative to pesticides.

PubMed

Molinari, Sergio

2011-03-01

Plant-parasitic nematodes are pests of a wide range of economically important crops, causing severe losses to agriculture. Natural genetic resistance of plants is expected to be a valid solution of the many problems nematodes cause all over the world. Progress in resistance applications is particularly important for the less-developed countries of tropical and subtropical regions, since use of resistant cultivars may be the only possible and economically feasible control strategy in those farming systems. Resistance is being considered of particular importance also in modern high-input production systems of developed countries, as the customary reliance on chemical nematicides has been restricted or has come to an end. This review briefly describes the genetic bases of resistance to nematodes in plants and focuses on the chances and problems of its exploitation as a key element in an integrated management program. Much space is dedicated to the major problem of resistance durability, in that the intensive use of resistant cultivars is likely to increasingly induce the selection of virulent populations able to "break" the resistance. Protocols of pest-host suitability are described, as bioassays are being used to evaluate local nematode populations in their potential to be selected on resistant germplasm and endanger resistant crops. The recent progress in using robust and durable resistances against nematodes as an efficient method for growers in vegetable cropping systems is reported, as well as the possible use of chemicals that do not show any unfavorable impact on environment, to induce in plants resistance against plant-parasitic nematodes.

Estimation of Whole Plant Photosynthetic Rate of Irwin Mango under Artificial and Natural Lights Using a Three-Dimensional Plant Model and Ray-Tracing.

PubMed

Jung, Dae Ho; Lee, Joon Woo; Kang, Woo Hyun; Hwang, In Ha; Son, Jung Eek

2018-01-04

Photosynthesis is an important physiological response for determination of CO₂ fertilization in greenhouses and estimation of crop growth. In order to estimate the whole plant photosynthetic rate, it is necessary to investigate how light interception by crops changes with environmental and morphological factors. The objectives of this study were to analyze plant light interception using a three-dimensional (3D) plant model and ray-tracing, determine the spatial distribution of the photosynthetic rate, and estimate the whole plant photosynthetic rate of Irwin mango ( Mangifera indica L. cv. Irwin) grown in greenhouses. In the case of mangoes, it is difficult to measure actual light interception at the canopy level due to their vase shape. A two-year-old Irwin mango tree was used to measure the whole plant photosynthetic rate. Light interception and whole plant photosynthetic rate were measured under artificial and natural light conditions using a closed chamber (1 × 1 × 2 m). A 3D plant model was constructed and ray-tracing simulation was conducted for calculating the photosynthetic rate with a two-variable leaf photosynthetic rate model of the plant. Under artificial light, the estimated photosynthetic rate increased from 2.0 to 2.9 μmolCO₂·m -2 ·s -1 with increasing CO₂ concentration. On the other hand, under natural light, the photosynthetic rate increased from 0.2 μmolCO₂·m -2 ·s -1 at 06:00 to a maximum of 7.3 μmolCO₂·m -2 ·s -1 at 09:00, then gradually decreased to -1.0 μmolCO₂·m -2 ·s -1 at 18:00. In validation, simulation results showed good agreement with measured results with R ² = 0.79 and RMSE = 0.263. The results suggest that this method could accurately estimate the whole plant photosynthetic rate and be useful for pruning and adequate CO₂ fertilization.

Design, test, and evaluation of three active flutter suppression controllers

NASA Technical Reports Server (NTRS)

Adams, William M., Jr.; Christhilf, David M.; Waszak, Martin R.; Mukhopadhyay, Vivek; Srinathkumar, S.

1992-01-01

Three control law design techniques for flutter suppression are presented. Each technique uses multiple control surfaces and/or sensors. The first method uses traditional tools (such as pole/zero loci and Nyquist diagrams) for producing a controller that has minimal complexity and which is sufficiently robust to handle plant uncertainty. The second procedure uses linear combinations of several accelerometer signals and dynamic compensation to synthesize the model rate of the critical mode for feedback to the distributed control surfaces. The third technique starts with a minimum-energy linear quadratic Gaussian controller, iteratively modifies intensity matrices corresponding to input and output noise, and applies controller order reduction to achieve a low-order, robust controller. The resulting designs were implemented digitally and tested subsonically on the active flexible wing wind-tunnel model in the Langley Transonic Dynamics Tunnel. Only the traditional pole/zero loci design was sufficiently robust to errors in the nominal plant to successfully suppress flutter during the test. The traditional pole/zero loci design provided simultaneous suppression of symmetric and antisymmetric flutter with a 24-percent increase in attainable dynamic pressure. Posttest analyses are shown which illustrate the problems encountered with the other laws.

Intragenic Suppression of a Trafficking-Defective Brassinosteroid Receptor Mutant in Arabidopsis

PubMed Central

Belkhadir, Youssef; Durbak, Amanda; Wierzba, Michael; Schmitz, Robert J.; Aguirre, Andrea; Michel, Rene; Rowe, Scott; Fujioka, Shozo; Tax, Frans E.

2010-01-01

The cell surface receptor kinase BRASSINOSTEROID-INSENSITIVE-1 (BRI1) is the major receptor for steroid hormones in Arabidopsis. Plants homozygous for loss-of-function mutations in BRI1 display a reduction in the size of vegetative organs, resulting in dwarfism. The recessive bri1-5 mutation produces receptors that do not accumulate to wild-type levels and are retained mainly in the endoplasmic reticulum. We have isolated a dominant suppressor of the dwarf phenotype of bri1-5 plants. We show that this suppression is caused by a second-site mutation in BRI1, bri1-5R1. The bri1-5R1 mutation partially rescues the phenotypes of bri1-5 in many tissues and enhances bri1-5 phenotypes above wild-type levels in several other tissues. We demonstrate that the phenotypes of bri1-5R1 plants are due to both increased cell expansion and increased cell division. To test the mechanism of bri1-5 suppression, we assessed whether the phenotypic suppression in bri1-5R1 was dependent on ligand availability and the integrity of the signaling pathway. Our results indicate that the suppression of the dwarf phenotypes associated with bri1-5R1 requires both BR biosynthesis and the receptor kinase BRI1-ASSOCIATED KINASE-1 (BAK1). Finally, we show that bri1-5R1 partially restores the accumulation and plasma membrane localization of BRI1. Collectively, our results point toward a model in which bri1-R1 compensates for the protein-folding abnormalities caused by bri1-5, restoring accumulation of the receptor and its delivery to the cell surface. PMID:20457881

Evaluation of antioxidant, in vitro cytotoxicity of micropropagated and naturally grown plants of Leptadenia reticulata (Retz.) Wight & Arn.-an endangered medicinal plant.

PubMed

Mohanty, Sudipta Kumar; Malappa, Kumaraswamy; Godavarthi, Ashok; Subbanarasiman, Balasubramanya; Maniyam, Anuradha

2014-09-01

To evaluate the antioxidant and anti proliferative potential of different solvent extract of micropropagated and naturally grown plants of Leptadenia reticulata against various cancer cell lines. In this study different extract were tested for cytotoxicity against human breast adenocarcinoma cell line MCF-7, human colon adenocarcinoma grade II cell line HT-29 and non cancer skeletal muscle cell line L6 through 3-(4, 5-dimethyl thiazol-2-yl)-5-diphenyl tetrazolium bromide assay. The total antioxidant potential was estimated by three different antioxidant model diphenylpicrylhydrazyl free radical scavenging activity, H2O2 scavenging activity and FeCl3 reducing activity. The ethyl acetate extract of both naturally grown plant and tissue cultured plant exhibited significant cytotoxicity with IC50 values of 21 µg/mL, 26 µg/mL and 22 µg/mL; 20 µg/mL, 30 µg/mL and 18 µg/mL respectively against three cell lines. The diphenylpicrylhydrazyl free radical scavenging activity was found to be highest with IC50 value of 267.13 µg/mL in ethyl acetate extract. The methanolic extract exhibited moderate antioxidant activity with IC50 value of 510.15 µg/mL. A highly positive correlation was observed between the antioxidant potential and cytotoxic activity of the plant. The strong cytotoxicity of ethyl acetate extract revealed anti carcinogenic potential of the plant which supports its traditional use as medicine. The present investigation is new to literature till date and will provide better scientific basis for future pharmacological, in vivo studies and novel source of pure bioactive compounds having anti cancer properties in this plant. Copyright © 2014 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

Jasmonic acid-mediated defense suppresses brassinosteroid-mediated susceptibility to Rice black streaked dwarf virus infection in rice.

PubMed

He, Yuqing; Zhang, Hehong; Sun, Zongtao; Li, Junmin; Hong, Gaojie; Zhu, Qisong; Zhou, Xuebiao; MacFarlane, Stuart; Yan, Fei; Chen, Jianping

2017-04-01

Plant hormones play a vital role in plant immune responses. However, in contrast to the relative wealth of information on hormone-mediated immunity in dicot plants, little information is available on monocot-virus defense systems. We used a high-throughput-sequencing approach to compare the global gene expression of Rice black-streaked dwarf virus (RBSDV)-infected rice plants with that of healthy plants. Exogenous hormone applications and transgenic rice were used to test RBSDV infectivity and pathogenicity. Our results revealed that the jasmonic acid (JA) pathway was induced while the brassinosteroid (BR) pathway was suppressed in infected plants. Foliar application of methyl jasmonate (MeJA) or brassinazole (BRZ) resulted in a significant reduction in RBSDV incidence, while epibrassinolide (BL) treatment increased RBSDV infection. Infection studies using coi1-13 and Go mutants demonstrated JA-mediated resistance and BR-mediated susceptibility to RBSDV infection. A mixture of MeJA and BL treatment resulted in a significant reduction in RBSDV infection compared with a single BL treatment. MeJA application efficiently suppressed the expression of BR pathway genes, and this inhibition depended on the JA coreceptor OsCOI1. Collectively, our results reveal that JA-mediated defense can suppress the BR-mediated susceptibility to RBSDV infection. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Interactions in Natural Colloid Systems "Biosolids" - Soil and Plant

NASA Astrophysics Data System (ADS)

Kalinichenko, Kira V.; Nikovskaya, Galina N.; Ulberg, Zoya R.

2016-04-01

The "biosolids" are complex biocolloid system arising in huge amounts (mln tons per year) from biological municipal wastewater treatment. These contain clusters of nanoparticles of heavy metal compounds (in slightly soluble or unsoluble forms, such as phosphates, sulphates, carbonates, hydroxides, and etc.), cells, humic substances and so on, involved in exopolysaccharides (EPS) net matrix. One may consider that biosolids are the natural nanocomposite. Due to the presence of nitrogen, phosphorus, potassium and other macro- and microelements (heavy metals), vitamins, aminoacids, etc., the biosolids are a depot of bioelements for plant nutrition. Thus, it is generally recognized that most rationally to utilize them for land application. For this purpose the biocolloid process was developed in biosolids system by initiation of microbial vital ability followed by the synthesis of EPS, propagation of ecologically important microorganisms, loosening of the structure and weakening of the coagulation contacts between biosolids colloids, but the structure integrity maintaining [1,2]. It was demonstrated that the applying of biosolids with metabolizing microorganisms to soil provided the improving soil structure, namely the increasing of waterstable aggregates content (70% vs. 20%). It occurs due to flocculation ability of biosolids EPS. The experimental modelling of mutual interactions in systems of soils - biosolids (with metabolizing microorganisms) were realized and their colloid and chemical mechanisms were formulated [3]. As it is known, the most harmonious plant growth comes at a prolonged entering of nutrients under the action of plant roots exudates which include pool of organic acids and polysaccharides [4]. Special investigations showed that under the influence of exudates excreted by growing plants, the biosolids microelements can release gradually from immobilized state into environment and are able to absorb by plants. Thus, the biosolids can serve as an active

Influence of plant origin natural α-pinene with different enantiomeric composition on bacteria, yeasts and fungi.

PubMed

Ložienė, Kristina; Švedienė, Jurgita; Paškevičius, Algimantas; Raudonienė, Vita; Sytar, Oksana; Kosyan, Anatoliy

2018-04-22

Although the nature-identical chemical compounds are cheaper, they not always repeat biological activity of plant origin natural chemical compounds, often react allergies and resistance of microorganisms. The aim of this study was to investigate effects of Juniperus communis origin α-pinene with different enantiomeric composition on bacteria, yeasts and fungi. Results showed that different enantiomeric composition of α-pinene have different activities on microorganisms: essential oil with (1S)-(-) ≈ (1R)-(+) enantiomeric composition of α-pinene influenced on some microorganisms stronger than essential oil with (1S)-(-) < (1R)-(+) enantiomeric composition of α-pinene; the pure natural α-pinene with enantiomeric composition S < R more strongly inhibited growth of investigated bacteria and Candida yeasts, α-pinene with enantiomeric composition S ≈ R - growth of Trichophyton and Aspergillus. (1S)-(-) and (1R)-(+) enantiomeric forms of α-pinene can have also different synergistic effects with other compounds of essential oil. The results of study showed that the same amount of α-pinene with different enantiomeric composition can have diverse antimicrobial potential due different specific interactions with other chemical compounds of essential oil. Therefore, it is very important to determine and present the enantiomeric composition of those plant origin compounds, which are characterized by enantiomerisation, during the course of research of biological activities of natural plant products (essential oils and other) and their isolated compounds. Copyright © 2018 Elsevier B.V. All rights reserved.

Transcriptomic and metabolomic analysis of Yukon Thellungiella plants grown in cabinets and their natural habitat show phenotypic plasticity

PubMed Central

2012-01-01

Background Thellungiella salsuginea is an important model plant due to its natural tolerance to abiotic stresses including salt, cold, and water deficits. Microarray and metabolite profiling have shown that Thellungiella undergoes stress-responsive changes in transcript and organic solute abundance when grown under controlled environmental conditions. However, few reports assess the capacity of plants to display stress-responsive traits in natural habitats where concurrent stresses are the norm. Results To determine whether stress-responsive changes observed in cabinet-grown plants are recapitulated in the field, we analyzed leaf transcript and metabolic profiles of Thellungiella growing in its native Yukon habitat during two years of contrasting meteorological conditions. We found 673 genes showing differential expression between field and unstressed, chamber-grown plants. There were comparatively few overlaps between genes expressed under field and cabinet treatment-specific conditions. Only 20 of 99 drought-responsive genes were expressed both in the field during a year of low precipitation and in plants subjected to drought treatments in cabinets. There was also a general pattern of lower abundance among metabolites found in field plants relative to control or stress-treated plants in growth cabinets. Nutrient availability may explain some of the observed differences. For example, proline accumulated to high levels in cold and salt-stressed cabinet-grown plants but proline content was, by comparison, negligible in plants at a saline Yukon field site. We show that proline accumulated in a stress-responsive manner in Thellungiella plants salinized in growth cabinets and in salt-stressed seedlings when nitrogen was provided at 1.0 mM. In seedlings grown on 0.1 mM nitrogen medium, the proline content was low while carbohydrates increased. The relatively higher content of sugar-like compounds in field plants and seedlings on low nitrogen media suggests that

Efficient electrochemical refrigeration power plant using natural gas with ∼100% CO2 capture

NASA Astrophysics Data System (ADS)

Al-musleh, Easa I.; Mallapragada, Dharik S.; Agrawal, Rakesh

2015-01-01

We propose an efficient Natural Gas (NG) based Solid Oxide Fuel Cell (SOFC) power plant equipped with ∼100% CO2 capture. The power plant uses a unique refrigeration based process to capture and liquefy CO2 from the SOFC exhaust. The capture of CO2 is carried out via condensation and purification using two rectifying columns operating at different pressures. The uncondensed gas mixture, comprising of relatively high purity unconverted fuel, is recycled to the SOFC and found to boost the power generation of the SOFC by 22%, when compared to a stand alone SOFC. If Liquefied Natural Gas (LNG) is available at the plant gate, then the refrigeration available from its evaporation is used for CO2 Capture and Liquefaction (CO2CL). If NG is utilized, then a Mixed Refrigerant (MR) vapor compression cycle is utilized for CO2CL. Alternatively, the necessary refrigeration can be supplied by evaporating the captured liquid CO2 at a lower pressure, which is then compressed to supercritical pressures for pipeline transportation. From rigorous simulations, the power generation efficiency of the proposed processes is found to be 70-76% based on lower heating value (LHV). The benefit of the proposed processes is evident when the efficiency of 73% for a conventional SOFC-Gas turbine power plant without CO2 capture is compared with an equivalent efficiency of 71.2% for the proposed process with CO2CL.

Plant Glandular Trichomes: Natural Cell Factories of High Biotechnological Interest1[OPEN

PubMed Central

2017-01-01

Multicellular glandular trichomes are epidermal outgrowths characterized by the presence of a head made of cells that have the ability to secrete or store large quantities of specialized metabolites. Our understanding of the transcriptional control of glandular trichome initiation and development is still in its infancy. This review points to some central questions that need to be addressed to better understand how such specialized cell structures arise from the plant protodermis. A key and unique feature of glandular trichomes is their ability to synthesize and secrete large amounts, relative to their size, of a limited number of metabolites. As such, they qualify as true cell factories, making them interesting targets for metabolic engineering. In this review, recent advances regarding terpene metabolic engineering are highlighted, with a special focus on tobacco (Nicotiana tabacum). In particular, the choice of transcriptional promoters to drive transgene expression and the best ways to sink existing pools of terpene precursors are discussed. The bioavailability of existing pools of natural precursor molecules is a key parameter and is controlled by so-called cross talk between different biosynthetic pathways. As highlighted in this review, the exact nature and extent of such cross talk are only partially understood at present. In the future, awareness of, and detailed knowledge on, the biology of plant glandular trichome development and metabolism will generate new leads to tap the largely unexploited potential of glandular trichomes in plant resistance to pests and lead to the improved production of specialized metabolites with high industrial or pharmacological value. PMID:28724619

The NS3 protein of Rice hoja blanca tenuivirus suppresses RNA silencing in plant and insect hosts by efficiently binding both siRNAs and miRNAs

PubMed Central

Hemmes, Hans; Lakatos, Lóránt; Goldbach, Rob; Burgyán, József; Prins, Marcel

2007-01-01

RNA silencing plays a key role in antiviral defense as well as in developmental processes in plants and insects. Negative strand RNA viruses such as the plant virus Rice hoja blanca tenuivirus (RHBV) replicate in plants and in their insect transmission vector. Like most plant-infecting viruses, RHBV encodes an RNA silencing suppressor, the NS3 protein, and here it is demonstrated that this protein is capable of suppressing RNA silencing in both plants and insect cells. Biochemical analyses showed that NS3 efficiently binds siRNA as well as miRNA molecules. Binding of NS3 is greatly influenced by the size of small RNA molecules, as 21 nucleotide (nt) siRNA molecules are bound > 100 times more efficiently than 26 nt species. Competition assays suggest that the activity of NS3 is based on binding to siRNAs prior to strand separation during the assembly of the RNA-induced silencing complex. In addition, NS3 has a high affinity for miRNA/miRNA* duplexes, indicating that its activity might also interfere with miRNA-regulated gene expression in both insects and plants. PMID:17513697

Nutrient Presses and Pulses Differentially Impact Plants, Herbivores, Detritivores and Their Natural Enemies

PubMed Central

Murphy, Shannon M.; Wimp, Gina M.; Lewis, Danny

2012-01-01

Anthropogenic nutrient inputs into native ecosystems cause fluctuations in resources that normally limit plant growth, which has important consequences for associated food webs. Such inputs from agricultural and urban habitats into nearby natural systems are increasing globally and can be highly variable, spanning the range from sporadic to continuous. Despite the global increase in anthropogenically-derived nutrient inputs into native ecosystems, the consequences of variation in subsidy duration on native plants and their associated food webs are poorly known. Specifically, while some studies have examined the effects of nutrient subsidies on native ecosystems for a single year (a nutrient pulse), repeated introductions of nutrients across multiple years (a nutrient press) better reflect the persistent nature of anthropogenic nutrient enrichment. We therefore contrasted the effects of a one-year nutrient pulse with a four-year nutrient press on arthropod consumers in two salt marshes. Salt marshes represent an ideal system to address the differential impacts of nutrient pulses and presses on ecosystem and community dynamics because human development and other anthropogenic activities lead to recurrent introductions of nutrients into these natural systems. We found that plant biomass and %N as well as arthropod density fell after the nutrient pulse ended but remained elevated throughout the nutrient press. Notably, higher trophic levels responded more strongly than lower trophic levels to fertilization, and the predator/prey ratio increased each year of the nutrient press, demonstrating that food web responses to anthropogenic nutrient enrichment can take years to fully manifest themselves. Vegetation at the two marshes also exhibited an apparent tradeoff between increasing %N and biomass in response to fertilization. Our research emphasizes the need for long-term, spatially diverse studies of nutrient enrichment in order to understand how variation in the duration

Weed suppression greatly increased by plant diversity in intensively managed grasslands: A continental-scale experiment.

PubMed

Connolly, John; Sebastià, Maria-Teresa; Kirwan, Laura; Finn, John Anthony; Llurba, Rosa; Suter, Matthias; Collins, Rosemary P; Porqueddu, Claudio; Helgadóttir, Áslaug; Baadshaug, Ole H; Bélanger, Gilles; Black, Alistair; Brophy, Caroline; Čop, Jure; Dalmannsdóttir, Sigridur; Delgado, Ignacio; Elgersma, Anjo; Fothergill, Michael; Frankow-Lindberg, Bodil E; Ghesquiere, An; Golinski, Piotr; Grieu, Philippe; Gustavsson, Anne-Maj; Höglind, Mats; Huguenin-Elie, Olivier; Jørgensen, Marit; Kadziuliene, Zydre; Lunnan, Tor; Nykanen-Kurki, Paivi; Ribas, Angela; Taube, Friedhelm; Thumm, Ulrich; De Vliegher, Alex; Lüscher, Andreas

2018-03-01

Grassland diversity can support sustainable intensification of grassland production through increased yields, reduced inputs and limited weed invasion. We report the effects of diversity on weed suppression from 3 years of a 31-site continental-scale field experiment.At each site, 15 grassland communities comprising four monocultures and 11 four-species mixtures based on a wide range of species' proportions were sown at two densities and managed by cutting. Forage species were selected according to two crossed functional traits, "method of nitrogen acquisition" and "pattern of temporal development".Across sites, years and sown densities, annual weed biomass in mixtures and monocultures was 0.5 and 2.0 t  DM ha -1 (7% and 33% of total biomass respectively). Over 95% of mixtures had weed biomass lower than the average of monocultures, and in two-thirds of cases, lower than in the most suppressive monoculture (transgressive suppression). Suppression was significantly transgressive for 58% of site-years. Transgressive suppression by mixtures was maintained across years, independent of site productivity.Based on models, average weed biomass in mixture over the whole experiment was 52% less (95% confidence interval: 30%-75%) than in the most suppressive monoculture. Transgressive suppression of weed biomass was significant at each year across all mixtures and for each mixture.Weed biomass was consistently low across all mixtures and years and was in some cases significantly but not largely different from that in the equiproportional mixture. The average variability (standard deviation) of annual weed biomass within a site was much lower for mixtures (0.42) than for monocultures (1.77). Synthesis and applications . Weed invasion can be diminished through a combination of forage species selected for complementarity and persistence traits in systems designed to reduce reliance on fertiliser nitrogen. In this study, effects of diversity on weed suppression were

Inoculation with arbuscular mycorrhizal fungi suppresses initiation of haustoria in the root hemiparasite Pedicularis tricolor.

PubMed

Li, Ai-Rong; Smith, Sally E; Smith, F Andrew; Guan, Kai-Yun

2012-05-01

Plant parasitism and arbuscular mycorrhizal (AM) associations have many parallels and share a number of regulatory pathways. Despite a rapid increase in investigations addressing the roles of AM fungi in regulating interactions between parasitic plants and their hosts, few studies have tested the effect of AM fungi on the initiation and differentiation of haustoria, the parasite-specific structures exclusively responsible for host attachment and nutrient transfer. In this study, we tested the influence of AM fungi on haustorium formation in a root hemiparasitic plant. Using a facultative root hemiparasitic species (Pedicularis tricolor) with the potential to form AM associations, the effects of inoculation were tested with two AM fungal species, Glomus mosseae and Glomus intraradices, on haustorium initiation in P. tricolor grown alone or with Hordeum vulgare 'Fleet' (barley) as the host plant. This study consisted of two greenhouse pot experiments. Both AM fungal species dramatically suppressed intraspecific haustorium initiation in P. tricolor at a very low colonization level. The suppression over-rode inductive effects of the parasite's host plant on haustoria production and caused significant growth depression of P. tricolor. AM fungi had strong and direct suppressive effects on haustorium formation in the root hemiparasite. The significant role of AM fungi in haustorium initiation of parasitic plants was demonstrated for the first time. This study provides new clues for the regulation of haustorium formation and a route to development of new biocontrol strategies in management of parasitic weeds.

43 CFR 6302.15 - When and how may I collect or disturb natural resources such as rocks and plants in wilderness...

Code of Federal Regulations, 2012 CFR

2012-10-01

... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false When and how may I collect or disturb natural resources such as rocks and plants in wilderness areas? 6302.15 Section 6302.15 Public Lands... disturb natural resources such as rocks and plants in wilderness areas? (a) You may remove or disturb...

43 CFR 6302.15 - When and how may I collect or disturb natural resources such as rocks and plants in wilderness...

Code of Federal Regulations, 2014 CFR

2014-10-01

... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false When and how may I collect or disturb natural resources such as rocks and plants in wilderness areas? 6302.15 Section 6302.15 Public Lands... disturb natural resources such as rocks and plants in wilderness areas? (a) You may remove or disturb...

43 CFR 6302.15 - When and how may I collect or disturb natural resources such as rocks and plants in wilderness...

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false When and how may I collect or disturb natural resources such as rocks and plants in wilderness areas? 6302.15 Section 6302.15 Public Lands... disturb natural resources such as rocks and plants in wilderness areas? (a) You may remove or disturb...

43 CFR 6302.15 - When and how may I collect or disturb natural resources such as rocks and plants in wilderness...

Code of Federal Regulations, 2013 CFR

2013-10-01

... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false When and how may I collect or disturb natural resources such as rocks and plants in wilderness areas? 6302.15 Section 6302.15 Public Lands... disturb natural resources such as rocks and plants in wilderness areas? (a) You may remove or disturb...

Xanthomonas campestris cell–cell signalling molecule DSF (diffusible signal factor) elicits innate immunity in plants and is suppressed by the exopolysaccharide xanthan

PubMed Central

Kakkar, Akanksha; Nizampatnam, Narasimha Rao; Kondreddy, Anil; Pradhan, Binod Bihari; Chatterjee, Subhadeep

2015-01-01

Several secreted and surface-associated conserved microbial molecules are recognized by the host to mount the defence response. One such evolutionarily well-conserved bacterial process is the production of cell–cell signalling molecules which regulate production of multiple virulence functions by a process known as quorum sensing. Here it is shown that a bacterial fatty acid cell–cell signalling molecule, DSF (diffusible signal factor), elicits innate immunity in plants. The DSF family of signalling molecules are highly conserved among many phytopathogenic bacteria belonging to the genus Xanthomonas as well as in opportunistic animal pathogens. Using Arabidopsis, Nicotiana benthamiana, and rice as model systems, it is shown that DSF induces a hypersensitivity reaction (HR)-like response, programmed cell death, the accumulation of autofluorescent compounds, hydrogen peroxide production, and the expression of the PATHOGENESIS-RELATED1 (PR-1) gene. Furthermore, production of the DSF signalling molecule in Pseudomonas syringae, a non-DSF-producing plant pathogen, induces the innate immune response in the N. benthamiana host plant and also affects pathogen growth. By pre- and co-inoculation of DSF, it was demonstrated that the DSF-induced plant defence reduces disease severity and pathogen growth in the host plant. In this study, it was further demonstrated that wild-type Xanthomonas campestris suppresses the DSF-induced innate immunity by secreting xanthan, the main component of extracellular polysaccharide. The results indicate that plants have evolved to recognize a widely conserved bacterial communication system and may have played a role in the co-evolution of host recognition of the pathogen and the communication machinery. PMID:26248667

Naturally occurring radioactive materials (NORMs) generated from lignite-fired power plants in Kosovo.

PubMed

Hasani, F; Shala, F; Xhixha, G; Xhixha, M K; Hodolli, G; Kadiri, S; Bylyku, E; Cfarku, F

2014-12-01

The energy production in Kosovo depends primarily on lignite-fired power plants. During coal combustion, huge amounts of fly ash and bottom ash are generated, which may result in enriched natural radionuclides; therefore, these radionuclides need to be investigated to identify the possible processes that may lead to the radiological exposure of workers and the local population. Lignite samples and NORMs of fly ash and bottom ash generated in lignite-fired power plants in Kosovo are analyzed using a gamma-ray spectrometry method for the activity concentration of natural radionuclides. The average activity concentrations of (40)K, (226)Ra and (232)Th in lignite are found to be 36 ± 8 Bq kg(-1), 9 ± 1 Bq kg(-1) and 9 ± 3 Bq kg(-1), respectively. Indications on the occurrence and geochemical behavior of uranium in the lignite matrix are suggested. The activity concentrations of natural radionuclides in fly ash and bottom ash samples are found to be concentrated from 3 to 5 times that of the feeding lignite. The external gamma-ray absorbed dose rate and the activity concentration index are calculated to assess the radiological hazard arising from ash disposal and recycling in the cement industry. Copyright © 2014 Elsevier Ltd. All rights reserved.

Natural AChE Inhibitors from Plants and their Contribution to Alzheimer’s Disease Therapy

PubMed Central

Murray, Ana Paula; Faraoni, María Belén; Castro, María Julia; Alza, Natalia Paola; Cavallaro, Valeria

2013-01-01

As acetylcholinesterase (AChE) inhibitors are an important therapeutic strategy in Alzheimer’s disease, efforts are being made in search of new molecules with anti-AChE activity. The fact that naturally-occurring compounds from plants are considered to be a potential source of new inhibitors has led to the discovery of an important number of secondary metabolites and plant extracts with the ability of inhibiting the enzyme AChE, which, according to the cholinergic hypothesis, increases the levels of the neurotransmitter acetylcholine in the brain, thus improving cholinergic functions in patients with Alzheimer’s disease and alleviating the symptoms of this neurological disorder. This review summarizes a total of 128 studies which correspond to the most relevant research work published during 2006-2012 (1st semester) on plant-derived compounds, plant extracts and essential oils found to elicit AChE inhibition. PMID:24381530

Role of nanomaterials in plants under challenging environments.

PubMed

Khan, M Nasir; Mobin, M; Abbas, Zahid Khorshid; AlMutairi, Khalid A; Siddiqui, Zahid H

2017-01-01

The application of nanostructured materials, designed for sustainable crop production, reduces nutrient losses, suppresses disease and enhances the yields. Nanomaterials (NMs), with a particle size less than 100 nm, influence key life events of the plants that include seed germination, seedling vigor, root initiation, growth and photosynthesis to flowering. Additionally, NMs have been implicated in the protection of plants against oxidative stress as they mimic the role of antioxidative enzymes such as superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX). However, besides their beneficial effects on plants, applications of NMs have been proved to be phytotoxic too as they enhance the generation of reactive oxygen species (ROS). The elevated level of ROS may damage the cellular membranes, proteins and nucleic acids. Therefore, in such a conflicting and ambiguous nature of NMs in plants, it is necessary to decipher the mechanism of cellular, biochemical and molecular protection render by NMs under stressful environmental conditions. This review systematically summarizes the role of NMs in plants under abiotic stresses such as drought, salt, temperature, metal, UV-B radiation and flooding. Furthermore, suitable strategies adopted by plants in presence of NMs under challenging environments are also being presented. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Convergent Evolution of Pathogen Effectors toward Reactive Oxygen Species Signaling Networks in Plants

PubMed Central

Jwa, Nam-Soo; Hwang, Byung Kook

2017-01-01

Microbial pathogens have evolved protein effectors to promote virulence and cause disease in host plants. Pathogen effectors delivered into plant cells suppress plant immune responses and modulate host metabolism to support the infection processes of pathogens. Reactive oxygen species (ROS) act as cellular signaling molecules to trigger plant immune responses, such as pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity. In this review, we discuss recent insights into the molecular functions of pathogen effectors that target multiple steps in the ROS signaling pathway in plants. The perception of PAMPs by pattern recognition receptors leads to the rapid and strong production of ROS through activation of NADPH oxidase Respiratory Burst Oxidase Homologs (RBOHs) as well as peroxidases. Specific pathogen effectors directly or indirectly interact with plant nucleotide-binding leucine-rich repeat receptors to induce ROS production and the hypersensitive response in plant cells. By contrast, virulent pathogens possess effectors capable of suppressing plant ROS bursts in different ways during infection. PAMP-triggered ROS bursts are suppressed by pathogen effectors that target mitogen-activated protein kinase cascades. Moreover, pathogen effectors target vesicle trafficking or metabolic priming, leading to the suppression of ROS production. Secreted pathogen effectors block the metabolic coenzyme NADP-malic enzyme, inhibiting the transfer of electrons to the NADPH oxidases (RBOHs) responsible for ROS generation. Collectively, pathogen effectors may have evolved to converge on a common host protein network to suppress the common plant immune system, including the ROS burst and cell death response in plants. PMID:29033963

Convergent Evolution of Pathogen Effectors toward Reactive Oxygen Species Signaling Networks in Plants.

PubMed

Jwa, Nam-Soo; Hwang, Byung Kook

2017-01-01

Microbial pathogens have evolved protein effectors to promote virulence and cause disease in host plants. Pathogen effectors delivered into plant cells suppress plant immune responses and modulate host metabolism to support the infection processes of pathogens. Reactive oxygen species (ROS) act as cellular signaling molecules to trigger plant immune responses, such as pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity. In this review, we discuss recent insights into the molecular functions of pathogen effectors that target multiple steps in the ROS signaling pathway in plants. The perception of PAMPs by pattern recognition receptors leads to the rapid and strong production of ROS through activation of NADPH oxidase Respiratory Burst Oxidase Homologs (RBOHs) as well as peroxidases. Specific pathogen effectors directly or indirectly interact with plant nucleotide-binding leucine-rich repeat receptors to induce ROS production and the hypersensitive response in plant cells. By contrast, virulent pathogens possess effectors capable of suppressing plant ROS bursts in different ways during infection. PAMP-triggered ROS bursts are suppressed by pathogen effectors that target mitogen-activated protein kinase cascades. Moreover, pathogen effectors target vesicle trafficking or metabolic priming, leading to the suppression of ROS production. Secreted pathogen effectors block the metabolic coenzyme NADP-malic enzyme, inhibiting the transfer of electrons to the NADPH oxidases (RBOHs) responsible for ROS generation. Collectively, pathogen effectors may have evolved to converge on a common host protein network to suppress the common plant immune system, including the ROS burst and cell death response in plants.

A Meloidogyne incognita effector MiISE5 suppresses programmed cell death to promote parasitism in host plant.

PubMed

Shi, Qianqian; Mao, Zhenchuan; Zhang, Xi; Zhang, Xiaoping; Wang, Yunsheng; Ling, Jian; Lin, Runmao; Li, Denghui; Kang, Xincong; Sun, Wenxian; Xie, Bingyan

2018-05-08

Root-knot nematodes (RKNs) are highly specialized parasites that interact with their host plants using a range of strategies. The esophageal glands are the main places where nematodes synthesize effector proteins, which play central roles in successful invasion. The Meloidogyne incognita effector MiISE5 is exclusively expressed within the subventral esophageal cells and is upregulated during early parasitic stages. In this study, we show that MiISE5 can be secreted to barley cells through infectious hyphae of Magnaporthe oryzae. Transgenic Arabidopsis plants expressing MiISE5 became significantly more susceptible to M. incognita. Inversely, the tobacco rattle virus (TRV)-mediated silence of MiISE5 decreased nematode parasitism. Moreover, transient expression of MiISE5 suppressed cell death caused by Burkholderia glumae in Nicotiana benthamiana. Based on transcriptome analysis of MiISE5 transgenic sample and the wild-type (WT) sample, we obtained 261 DEGs, and the results of GO and KEGG enrichment analysis indicate that MiISE5 can interfere with various metabolic and signaling pathways, especially the JA signaling pathway, to facilitate nematode parasitism. Results from the present study suggest that MiISE5 plays an important role during the early stages of parasitism and provides evidence to decipher the molecular mechanisms underlying the manipulation of host immune defense responses by M. incognita.

Apoplastic Venom Allergen-like Proteins of Cyst Nematodes Modulate the Activation of Basal Plant Innate Immunity by Cell Surface Receptors

PubMed Central

Lozano-Torres, Jose L.; Wilbers, Ruud H. P.; Warmerdam, Sonja; Finkers-Tomczak, Anna; Diaz-Granados, Amalia; van Schaik, Casper C.; Helder, Johannes; Bakker, Jaap; Goverse, Aska; Schots, Arjen; Smant, Geert

2014-01-01

Despite causing considerable damage to host tissue during the onset of parasitism, nematodes establish remarkably persistent infections in both animals and plants. It is thought that an elaborate repertoire of effector proteins in nematode secretions suppresses damage-triggered immune responses of the host. However, the nature and mode of action of most immunomodulatory compounds in nematode secretions are not well understood. Here, we show that venom allergen-like proteins of plant-parasitic nematodes selectively suppress host immunity mediated by surface-localized immune receptors. Venom allergen-like proteins are uniquely conserved in secretions of all animal- and plant-parasitic nematodes studied to date, but their role during the onset of parasitism has thus far remained elusive. Knocking-down the expression of the venom allergen-like protein Gr-VAP1 severely hampered the infectivity of the potato cyst nematode Globodera rostochiensis. By contrast, heterologous expression of Gr-VAP1 and two other venom allergen-like proteins from the beet cyst nematode Heterodera schachtii in plants resulted in the loss of basal immunity to multiple unrelated pathogens. The modulation of basal immunity by ectopic venom allergen-like proteins in Arabidopsis thaliana involved extracellular protease-based host defenses and non-photochemical quenching in chloroplasts. Non-photochemical quenching regulates the initiation of the defense-related programmed cell death, the onset of which was commonly suppressed by venom allergen-like proteins from G. rostochiensis, H. schachtii, and the root-knot nematode Meloidogyne incognita. Surprisingly, these venom allergen-like proteins only affected the programmed cell death mediated by surface-localized immune receptors. Furthermore, the delivery of venom allergen-like proteins into host tissue coincides with the enzymatic breakdown of plant cell walls by migratory nematodes. We, therefore, conclude that parasitic nematodes most likely utilize

Apoplastic venom allergen-like proteins of cyst nematodes modulate the activation of basal plant innate immunity by cell surface receptors.

PubMed

Lozano-Torres, Jose L; Wilbers, Ruud H P; Warmerdam, Sonja; Finkers-Tomczak, Anna; Diaz-Granados, Amalia; van Schaik, Casper C; Helder, Johannes; Bakker, Jaap; Goverse, Aska; Schots, Arjen; Smant, Geert

2014-12-01

Despite causing considerable damage to host tissue during the onset of parasitism, nematodes establish remarkably persistent infections in both animals and plants. It is thought that an elaborate repertoire of effector proteins in nematode secretions suppresses damage-triggered immune responses of the host. However, the nature and mode of action of most immunomodulatory compounds in nematode secretions are not well understood. Here, we show that venom allergen-like proteins of plant-parasitic nematodes selectively suppress host immunity mediated by surface-localized immune receptors. Venom allergen-like proteins are uniquely conserved in secretions of all animal- and plant-parasitic nematodes studied to date, but their role during the onset of parasitism has thus far remained elusive. Knocking-down the expression of the venom allergen-like protein Gr-VAP1 severely hampered the infectivity of the potato cyst nematode Globodera rostochiensis. By contrast, heterologous expression of Gr-VAP1 and two other venom allergen-like proteins from the beet cyst nematode Heterodera schachtii in plants resulted in the loss of basal immunity to multiple unrelated pathogens. The modulation of basal immunity by ectopic venom allergen-like proteins in Arabidopsis thaliana involved extracellular protease-based host defenses and non-photochemical quenching in chloroplasts. Non-photochemical quenching regulates the initiation of the defense-related programmed cell death, the onset of which was commonly suppressed by venom allergen-like proteins from G. rostochiensis, H. schachtii, and the root-knot nematode Meloidogyne incognita. Surprisingly, these venom allergen-like proteins only affected the programmed cell death mediated by surface-localized immune receptors. Furthermore, the delivery of venom allergen-like proteins into host tissue coincides with the enzymatic breakdown of plant cell walls by migratory nematodes. We, therefore, conclude that parasitic nematodes most likely utilize

Mitochondrial catalase suppresses naturally occurring lung cancer in old mice.

PubMed

Ge, Xuang; Pettan-Brewer, Christina; Morton, John; Carter, Katrina; Fatemi, Sy; Rabinovitch, Peter; Ladiges, Warren C

2015-01-01

Lung cancer is generally difficult to detect until the late stages of disease, when it is much more difficult to treat because of the more aggressive and invasive behavior. Advanced lung cancer is much more common in older adults making it even more challenging to treat. Adenocarcinoma belongs to a category of non-small cell lung cancers, which comprise up to 40% of all lung cancers, and about half of these have an activating K-ras mutation. Because treatment relapses are common, more effective unconventional treatment and prevention methods are needed. In this regard, the antioxidant enzyme catalase targeted to mitochondria (mCAT) has been shown to delay aging and cancer in mice, and the progression of transgenic oncogene and syngeneic tumors was suppressed, helping support the notion that attenuation of mitochondria-generated hydrogen peroxide signaling is associated with an antitumor effect. In order to determine if mCAT has any effect on naturally occurring lung cancer of the adenocarcinoma type in old mice, the tumor incidence and progression were examined in the lungs of old mCAT transgenic and wild-type (WT) mice with a CB6F1 (Balb/c X C57BL/6) background. CB6F1 mice with a WT genotype were found to have a high incidence of adenomas at 24 months of age, which progressed to adenocarcinomas at 32 months of age. CB6F1 mice with the mCAT genotype had significantly reduced incidence and severity of lung tumors at both ages. Fibroblasts isolated from the lungs of old mCAT mice, but not WT mice, were shown to secrete soluble factors that inhibited lung tumor cell growth suggesting that stromal fibroblasts play a role in mediating the antitumor effects of mCAT. The aged CB6F1 mouse, with its high incidence of K-ras mutant lung cancer, is an excellent model to further study the anticancer potential of mitochondria-targeted therapy.

Mitochondrial catalase suppresses naturally occurring lung cancer in old mice

PubMed Central

Ge, Xuang; Pettan-Brewer, Christina; Morton, John; Carter, Katrina; Fatemi, Sy; Rabinovitch, Peter; Ladiges, Warren C.

2015-01-01

Lung cancer is generally difficult to detect until the late stages of disease, when it is much more difficult to treat because of the more aggressive and invasive behavior. Advanced lung cancer is much more common in older adults making it even more challenging to treat. Adenocarcinoma belongs to a category of non-small cell lung cancers, which comprise up to 40% of all lung cancers, and about half of these have an activating K-ras mutation. Because treatment relapses are common, more effective unconventional treatment and prevention methods are needed. In this regard, the antioxidant enzyme catalase targeted to mitochondria (mCAT) has been shown to delay aging and cancer in mice, and the progression of transgenic oncogene and syngeneic tumors was suppressed, helping support the notion that attenuation of mitochondria-generated hydrogen peroxide signaling is associated with an antitumor effect. In order to determine if mCAT has any effect on naturally occurring lung cancer of the adenocarcinoma type in old mice, the tumor incidence and progression were examined in the lungs of old mCAT transgenic and wild-type (WT) mice with a CB6F1 (Balb/c X C57BL/6) background. CB6F1 mice with a WT genotype were found to have a high incidence of adenomas at 24 months of age, which progressed to adenocarcinomas at 32 months of age. CB6F1 mice with the mCAT genotype had significantly reduced incidence and severity of lung tumors at both ages. Fibroblasts isolated from the lungs of old mCAT mice, but not WT mice, were shown to secrete soluble factors that inhibited lung tumor cell growth suggesting that stromal fibroblasts play a role in mediating the antitumor effects of mCAT. The aged CB6F1 mouse, with its high incidence of K-ras mutant lung cancer, is an excellent model to further study the anticancer potential of mitochondria-targeted therapy. PMID:26400209

Evaluation, analysis, and documentation support for the 10-kw Signature Suppressed Lightweight Electric Energy Plant (SLEEP). Technical report, April 1987-March 1988

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

Morsch, B.A.; Main, B.W.; Buckman, A.F.

The US Army identified the need for a Signature Suppressed, Lightweight Electric Energy Plant (SLEEP) to improve the survivability of forward deployed units. The US Army Belvoir Research, Development and Engineering Center has the responsibility for procuring generators to meet this requirement. This study was to investigate power-generation technology and determine the most-effective technology to meet the SLEEP requirement. The Stirling was identified as the most-promising technology for SLEEP. Commercial systems and improvements to existing systems cannot meet this requirement. Procurement of SLEEP was determined to be well suited for the Army Streamlined Acquisition Program.

Reminiscences of research on the chemistry and biology of natural sterols in insects, plants and humans.

PubMed

Ikekawa, Nobuo; Fujimoto, Yoshinori; Ishiguro, Masaji

2013-01-01

Natural sterols often occur as a heterogeneous mixture of homologs, which had disturbed the progress of steroid research. Development and application of GC methodology overcame this difficulty and enabled us to obtain detailed sterol profiles. Together, fine synthesis of stereo-defined isomers and homologs of steroids having oxygenated side chains allowed us to compare them with natural samples as well as to investigate structure-activity relationship. Advance of HPLC technology also facilitated the determination of the stereochemical structure of naturally occurring steroidal compounds, which were obtained only in minute amounts. This review highlights three topics out of our steroid research that have been performed mainly at Tokyo Institute of Technology around 1970-1990. These are sterol metabolism in insects focusing on the mechanism of the conversion of plant sterols to cholesterol and ecdysone biosynthesis, the synthesis and biochemical research of active forms of vitamin D3 derivatives, and the synthesis and microanalysis of plant hormone brassinosteroids.

Analysis of Globodera rostochiensis effectors reveals conserved functions of SPRYSEC proteins in suppressing and eliciting plant immune responses.

PubMed

Ali, Shawkat; Magne, Maxime; Chen, Shiyan; Obradovic, Natasa; Jamshaid, Lubna; Wang, Xiaohong; Bélair, Guy; Moffett, Peter

2015-01-01

Potato cyst nematodes (PCNs), including Globodera rostochiensis (Woll.), are important pests of potato. Plant parasitic nematodes produce multiple effector proteins, secreted from their stylets, to successfully infect their hosts. These include proteins delivered to the apoplast and to the host cytoplasm. A number of effectors from G. rostochiensis predicted to be delivered to the host cytoplasm have been identified, including several belonging to the secreted SPRY domain (SPRYSEC) family. SPRYSEC proteins are unique to members of the genus Globodera and have been implicated in both the induction and the repression of host defense responses. We have tested the properties of six different G. rostochiensis SPRYSEC proteins by expressing them in Nicotiana benthamiana and N. tabacum. We have found that all SPRYSEC proteins tested are able to suppress defense responses induced by NB-LRR proteins as well as cell death induced by elicitors, suggesting that defense repression is a common characteristic of members of this effector protein family. At the same time, GrSPRYSEC-15 elicited a defense responses in N. tabacum, which was found to be resistant to a virus expressing GrSPRYSEC-15. These results suggest that SPRYSEC proteins may possess characteristics that allow them to be recognized by the plant immune system.

Synergistic effect of chickpea plants and Mesorhizobium as a natural system for chromium phytoremediation.

PubMed

Velez, Pilar A; Talano, Melina A; Paisio, Cintia E; Agostini, Elizabeth; González, Paola S

2017-09-01

The presence of chromium in soils not only affects the physiological processes of plants but also the microbial rhizosphere composition and metabolic activities of microorganisms. Hence, the inoculation of plants with Cr(VI)-tolerant rhizospheric microorganisms as an alternative to reduce Cr phytotoxicity was studied. In this work, chickpea germination was reduced by Cr(VI) concentrations of 150 and 250 mg/L (6 and 33%, respectively); however lower Cr(VI) concentrations negatively affected the biomass. On the other hand, its symbiont, Mesorhizobium ciceri, was able to grow and remove different Cr(VI) concentrations (5-20 mg/L). The inoculation of chickpea plants with this strain exposed to Cr(VI) showed a significantly enhanced plant growth. In addition, inoculated plants accumulated higher Cr concentration in roots than those noninoculated. It is important to note that Cr was not translocated to shoots independently of inoculation. These results suggest that Mesorhizobium's capability to remove Cr(VI) could be exploited for bioremediation. Moreover, chickpea plants would represent a natural system for phytoremediation or phytostabilization of Cr in situ that could be improved with M. ciceri inoculation. This strategy would be considered as a phytoremediation tool with great economic and ecological relevance.

[Differences in growth and ontogenetic development of plants grown in the Earth gravitational field in the natural and inverse orientation].

PubMed

Smolianina, S O; Berkovich, Iu A; Krivobok, N M; Ivanov, V B

2003-01-01

Wheat plants Triticum aestivum L., Apogee cultivar, were grown in the natural and inverse orientation of the Earth gravitational field. Special vegetation containers with double bottom were used for the cultivation. The upper bottom made of porous titanium served as a hydrophilic porous membrane stabilizing aquatic potential in the root-inhabited zone at a given level. Normal plants yielding viable seeds were obtained for both natural and inverse orientation. In our experiments, the inverse orientation induced dry weight accumulation by the plants as well as development of productive tillering shoots and increased the shoot-root dry weight ratio.

Medicinal Plants in Neurodegenerative Diseases: Perspective of Traditional Persian Medicine.

PubMed

Farzaei, Mohammad Hosein; Shahpiri, Zahra; Mehri, Mohammad Reza; Bahramsoltani, Roodabeh; Rezaei, Mahdi; Raeesdana, Azade; Rahimi, Roja

2018-01-01

Neurodegenerative diseases are a progressive loss of structure and/or function of neurons. Weak therapeutic response and progressive nature of the diseases, as well as a wide range of side effects caused by conventional therapeutic approaches make patients seek for complementary and alternative medicine. The aim of the present paper is to discuss the neuropharmacological basis of medicinal plants and their principle phytochemicals which have been used in traditional Persian medicine for different types of neurodegenerative diseases. Medicinal plants introduced in traditional Persian medicine perform beneficial effects in neurodegenerative diseases via various cellular and molecular mechanisms including suppression of apoptosis mediated by an increase in the expression of anti-apoptotic agents (e.g. Bcl-2) as well as a decrease in the expression and activity of proapoptotic proteins (e.g. Bax, caspase 3 and 9). Alleviating inflammatory responses and suppressing the expression and function of pro-inflammatory cytokines like Tumor necrosis factor α and interleukins, as well as improvement in antioxidative performance mediated by superoxide dismutase and catalase, are among other neuroprotective mechanisms of traditional medicinal plants. Modulation of transcription, transduction, intracellular signaling pathways including ERK, p38, and MAPK, with upstream regulatory activity on inflammatory cascades, apoptosis and oxidative stress associated pathways, play an essential role in the preventive and therapeutic potential of the plants in neurodegenerative diseases. Medicinal plants used in traditional Persian medicine along with their related phytochemicals by affecting various neuropharmacological pathways can be considered as future drugs or adjuvant therapies with conventional pharmacotherapeutics; though, further clinical studies are necessary for the confirmation of their safety and efficacy. Copyright© Bentham Science Publishers; For any queries, please email at

Plant-Pathogen Effectors: Cellular Probes Interfering with Plant Defenses in Spatial and Temporal Manners

PubMed Central

Toruño, Tania Y.; Stergiopoulos, Ioannis; Coaker, Gitta

2017-01-01

Plants possess large arsenals of immune receptors capable of recognizing all pathogen classes. To cause disease, pathogenic organisms must be able to overcome physical barriers, suppress or evade immune perception, and derive nutrients from host tissues. Consequently, to facilitate some of these processes, pathogens secrete effector proteins that promote colonization. This review covers recent advances in the field of effector biology, focusing on conserved cellular processes targeted by effectors from diverse pathogens. The ability of effectors to facilitate pathogen entry into the host interior, suppress plant immune perception, and alter host physiology for pathogen benefit is discussed. Pathogens also deploy effectors in a spatial and temporal manner, depending on infection stage. Recent advances have also enhanced our understanding of effectors acting in specific plant organs and tissues. Effectors are excellent cellular probes that facilitate insight into biological processes as well as key points of vulnerability in plant immune signaling networks. PMID:27359369

Relations between urban bird and plant communities and human well-being and connection to nature.

PubMed

Luck, Gary W; Davidson, Penny; Boxall, Dianne; Smallbone, Lisa

2011-08-01

By 2050, 70% of the world's population will live in urban areas. In many cases urbanization reduces the richness and abundance of native species. Living in highly modified environments with fewer opportunities to interact directly with a diversity of native species may adversely affect residents' personal well-being and emotional connection to nature. We assessed the personal well-being, neighborhood well-being (a measure of a person's satisfaction with their neighborhood), and level of connection to nature of over 1000 residents in 36 residential neighborhoods in southeastern Australia. We modeled these response variables as a function of natural features of each neighborhood (e.g., species richness and abundance of birds, density of plants, and amount of vegetation cover) and demographic characteristics of surveyed residents. Vegetation cover had the strongest positive relations with personal well-being, whereas residents' level of connection to nature was weakly related to variation in species richness and abundance of birds and density of plants. Demographic characteristics such as age and level of activity explained the greatest proportion of variance in well-being and connection to nature. Nevertheless, when controlling for variation in demographic characteristics (examples were provided above), neighborhood well-being was positively related to a range of natural features, including species richness and abundance of birds, and vegetation cover. Demographic characteristics and how well-being was quantified strongly influenced our results, and we suggest demography and metrics of well-being must be considered when attempting to determine relations between the urban environment and human well-being. © 2011 Society for Conservation Biology.

Intermediate-sized natural gas fueled carbonate fuel cell power plants

NASA Astrophysics Data System (ADS)

Sudhoff, Frederick A.; Fleming, Donald K.

1994-04-01

This executive summary of the report describes the accomplishments of the joint US Department of Energy's (DOE) Morgantown Energy Technology Center (METC) and M-C POWER Corporation's Cooperative Research and Development Agreement (CRADA) No. 93-013. This study addresses the intermediate power plant size between 2 megawatt (MW) and 200 MW. A 25 MW natural-gas, fueled-carbonate fuel cell power plant was chosen for this purpose. In keeping with recent designs, the fuel cell will operate under approximately three atmospheres of pressure. An expander/alternator is utilized to expand exhaust gas to atmospheric conditions and generate additional power. A steam-bottoming cycle is not included in this study because it is not believed to be cost effective for this system size. This study also addresses the simplicity and accuracy of a spreadsheet-based simulation with that of a full Advanced System for Process Engineering (ASPEN) simulation. The personal computer can fully utilize the simple spreadsheet model simulation. This model can be made available to all users and is particularly advantageous to the small business user.

Different Traits Determine Introduction, Naturalization and Invasion Success In Woody Plants: Proteaceae as a Test Case

PubMed Central

Moodley, Desika; Geerts, Sjirk; Richardson, David M.; Wilson, John R. U.

2013-01-01

A major aim of invasion ecology is to identify characteristics of successful invaders. However, most plant groups studied in detail (e.g. pines and acacias) have a high percentage of invasive taxa. Here we examine the global introduction history and invasion ecology of Proteaceae—a large plant family with many taxa that have been widely disseminated by humans, but with few known invaders. To do this we compiled a global list of species and used boosted regression tree models to assess which factors are important in determining the status of a species (not introduced, introduced, naturalized or invasive). At least 402 of 1674 known species (24%) have been moved by humans out of their native ranges, 58 species (14%) have become naturalized but not invasive, and 8 species (2%) are invasive. The probability of naturalization was greatest for species with large native ranges, low susceptibility to Phytophthora root-rot fungus, large mammal-dispersed seeds, and with the capacity to resprout. The probability of naturalized species becoming invasive was greatest for species with large native ranges, those used as barrier plants, tall species, species with small seeds, and serotinous species. The traits driving invasiveness of Proteaceae were similar to those for acacias and pines. However, while some traits showed a consistent influence at introduction, naturalization and invasion, others appear to be influential at one stage only, and some have contrasting effects at different stages. Trait-based analyses therefore need to consider different invasion stages separately. On their own, these observations provide little predictive power for risk assessment, but when the causative mechanisms are understood (e.g. Phytophthora susceptibility) they provide valuable insights. As such there is considerable value in seeking the correlates and mechanisms underlying invasions for particular taxonomic or functional groups. PMID:24086442

Effects of invasive alien kahili ginger (Hedychium gardnerianum) on native plant species regeneration in a Hawaiian rainforest

USGS Publications Warehouse

Minden, V.; Jacobi, J.D.; Porembski, S.; Boehmer, H.J.

2010-01-01

Questions: Does the invasive alien Hedychium gardnerianum (1) replace native understory species, (2) suppress natural regeneration of native plant species, (3) increase the invasiveness of other non-native plants and (4) are native forests are able to recover after removal of H. gardnerianum. Location: A mature rainforest in Hawai'i Volcanoes National Park on the island of Hawai'i (about 1200 m. a.s.l.; precipitation approximately 2770mm yr-1). Study sites included natural plots without effects of alien plants, ginger plots with a H. gardnerianum-domimted herb layer and cleared plots treated with herbicide to remove alien plants. Methods: Counting mature trees, saplings and seedlings of native and alien plant species. Using nonparametric H-tests to compare impact of H. gardnerianum on the structure of different sites. Results: Results confirmed the hypothesis that H. gardnerianum has negative effects on natural forest dynamics. Lower numbers of native tree seedlings and saplings were found on ginger-dominated plots. Furthermore, H. gardnerianum did not show negative effects on the invasive alien tree species Psidium cattleianum. Conclusions: This study reveals that where dominance of H. gardnerianum persists, regeneration of the forest by native species will be inhibited. Furthermore, these areas might experience invasion by P. cattleianum, resulting in displacement of native canopy species in the future, leading to a change in forest structure and loss of other species dependent on natural rainforest, such as endemic birds. However, if H. gardnerianum is removed the native Hawaiian forest is likely to regenerate and regain its natural structure. ?? 2009 International Association for Vegetation Science.

An Overview of Natural Plant Products in the Treatment of Hepatocellular Carcinoma.

PubMed

Rawat, Divya; Shrivastava, Somi; Naik, Rayees Ahmad; Chhonker, Saurabh Kumar; Mehrotra, Aditi; Koiri, Raj Kumar

2018-06-03

Liver cancer is the fifth most commonly diagnosed cancer and the second leading cause of cancer related deaths worldwide. Among the liver cancers, hepatocellular carcinoma has been reported to be responsible for 85-90% of primary liver cancer and it is the second most common cause of cancer mortality with 700,000 deaths documented annually. The major risk factors of HCC include chronic infections with the hepatitis B (HBV) or hepatitis C (HCV) virus, chronic liver diseases, alcoholism as well as dietary carcinogens, such as aflatoxins. Highest incidence rates are estimated to occur in Asia and Africa. The effectiveness of current man-made agents in treating chronic liver disease is not satisfactory and they have uninvited side effects. Herbal medicines are extensively used all over the world; however there is still a vast gap in accepting them by the scientific community. Plants are rich in secondary metabolites and phytochemicals obtained from both, dietary and non-dietary sources. Natural plant products are potent therapeutic as well as chemo preventive agents for numerous chronic diseases like cardiovascular, metabolic, neurodegenerative and neoplastic diseases. Dietary phytochemicals such as curcumin, resveratrol, quercetin, silibinin, N-trans-feruloyloctopamine, lycopene, emodin, caffeine, urolithin A and Phloretin have been found to be useful for the treatment of HCC and other diseases and report estimate that 60% of the anticancer medication in current use has been obtained from natural sources. Thus, derivatives from plants have played an essential role in cancer prevention due to their pleiotropic abilities to scavenge free radicals, inhibit cell growth and induce apoptosis. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Large-Scale Identification and Characterization of Heterodera avenae Putative Effectors Suppressing or Inducing Cell Death in Nicotiana benthamiana

PubMed Central

Chen, Changlong; Chen, Yongpan; Jian, Heng; Yang, Dan; Dai, Yiran; Pan, Lingling; Shi, Fengwei; Yang, Shanshan; Liu, Qian

2018-01-01

Heterodera avenae is one of the most important plant pathogens and causes vast losses in cereal crops. As a sedentary endoparasitic nematode, H. avenae secretes effectors that modify plant defenses and promote its biotrophic infection of its hosts. However, the number of effectors involved in the interaction between H. avenae and host defenses remains unclear. Here, we report the identification of putative effectors in H. avenae that regulate plant defenses on a large scale. Our results showed that 78 of the 95 putative effectors suppressed programmed cell death (PCD) triggered by BAX and that 7 of the putative effectors themselves caused cell death in Nicotiana benthamiana. Among the cell-death-inducing effectors, three were found to be dependent on their specific domains to trigger cell death and to be expressed in esophageal gland cells by in situ hybridization. Ten candidate effectors that suppressed BAX-triggered PCD also suppressed PCD triggered by the elicitor PsojNIP and at least one R-protein/cognate effector pair, suggesting that they are active in suppressing both pattern-triggered immunity (PTI) and effector-triggered immunity (ETI). Notably, with the exception of isotig16060, these putative effectors could also suppress PCD triggered by cell-death-inducing effectors from H. avenae, indicating that those effectors may cooperate to promote nematode parasitism. Collectively, our results indicate that the majority of the tested effectors of H. avenae may play important roles in suppressing cell death induced by different elicitors in N. benthamiana. PMID:29379510

A ubiquitin carboxyl extension protein secreted from a plant-parasitic nematode Globodera rostochiensis is cleaved in planta to promote plant parasitism.

PubMed

Chronis, Demosthenis; Chen, Shiyan; Lu, Shunwen; Hewezi, Tarek; Carpenter, Sara C D; Loria, Rosemary; Baum, Thomas J; Wang, Xiaohong

2013-04-01

Nematode effector proteins originating from esophageal gland cells play central roles in suppressing plant defenses and in formation of the plant feeding cells that are required for growth and development of cyst nematodes. A gene (GrUBCEP12) encoding a unique ubiquitin carboxyl extension protein (UBCEP) that consists of a signal peptide for secretion, a mono-ubiquitin domain, and a 12 amino acid carboxyl extension protein (CEP12) domain was cloned from the potato cyst nematode Globodera rostochiensis. This GrUBCEP12 gene was expressed exclusively within the nematode's dorsal esophageal gland cell, and was up-regulated in the parasitic second-stage juvenile, correlating with the time when feeding cell formation is initiated. We showed that specific GrUBCEP12 knockdown via RNA interference reduced nematode parasitic success, and that over-expression of the secreted Gr(Δ) (SP) UBCEP12 protein in potato resulted in increased nematode susceptibility, providing direct evidence that this secreted effector is involved in plant parasitism. Using transient expression assays in Nicotiana benthamiana, we found that Gr(Δ) (SP) UBCEP12 is processed into free ubiquitin and a CEP12 peptide (GrCEP12) in planta, and that GrCEP12 suppresses resistance gene-mediated cell death. A target search showed that expression of RPN2a, a gene encoding a subunit of the 26S proteasome, was dramatically suppressed in Gr(Δ) (SP) UBCEP12 but not GrCEP12 over-expression plants when compared with control plants. Together, these results suggest that, when delivered into host plant cells, Gr(Δ) (SP) UBCEP12 becomes two functional units, one acting to suppress plant immunity and the other potentially affecting the host 26S proteasome, to promote feeding cell formation. © 2013 The Authors The Plant Journal © 2013 Blackwell Publishing Ltd.

Plants with useful traits and related methods

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

Mackenzie, Sally Ann; De la Rosa Santamaria, Roberto

The present invention provides methods for obtaining plants that exhibit useful traits by transient suppression of the MSH1 gene of the plants. Methods for identifying genetic loci that provide for useful traits in plants and plants produced with those loci are also provided. In addition, plants that exhibit the useful traits, parts of the plants including seeds, and products of the plants are provided as well as methods of using the plants.

Plants with useful traits and related methods

DOEpatents

Mackenzie, Sally Ann; De la Rosa Santamaria, Roberto

2017-07-18

The present invention provides methods for obtaining plants that exhibit useful traits by transient suppression of the MSH1 gene of the plants. Methods for identifying genetic loci that provide for useful traits in plants and plants produced with those loci are also provided. In addition, plants that exhibit the useful traits, parts of the plants including seeds, and products of the plants are provided as well as methods of using the plants.

Pine beauty moth (Panolis flammea Schiff.) outbreak management: suppression versus natural enemies

Treesearch

Paulius Zolubas

2003-01-01

Pine beauty moth (Panolis flammea Schiff.) is one of the most serious defoliators that periodically threatens Scotch pine forests on poor sandy soils in Lithuania. Population increase of this pest began in 1999. Because a maximum of only 15% defoliation was predicted in particular areas, no additional funding was required for suppressing the...

Nocturnal Fanning Suppresses Downy Mildew Epidemics in Sweet Basil

PubMed Central

Cohen, Yigal; Ben-Naim, Yariv

2016-01-01

Downy mildew is currently the most serious disease of sweet basil around the world. The oomycete causal agent Peronospora belbahrii requires ≥ 4h free leaf moisture for infection and ≥7.5h of water-saturated atmosphere (relative humidity RH≥95%) at night for sporulation. We show here that continued nocturnal fanning (wind speed of 0.4–1.5 m/s) from 8pm to 8am dramatically suppressed downy mildew development. In three experiments conducted during 2015, percent infected leaves in regular (non-fanned) net-houses reached a mean of 89.9, 94.3 and 96.0% compared to1.2, 1.7 and 0.5% in adjacent fanned net-houses, respectively. Nocturnal fanning reduced the number of hours per night with RH≥95% thus shortened the dew periods below the threshold required for infection or sporulation. In experiments A, B and C, the number of nights with ≥4h of RH≥95% was 28, 10 and 17 in the non-fanned net-houses compared to 5, 0 and 5 in the fanned net-houses, respectively. In the third experiment leaf wetness sensors were installed. Dew formation was strongly suppressed in the fanned net-house as compared to the non-fanned net-house. Healthy potted plants became infected and sporulated a week later if placed one night in the non-fanned house whereas healthy plants placed during that night in the fanned house remained healthy. Infected potted basil plants sporulated heavily after one night of incubation in the non-fanned house whereas almost no sporulation occurred in similar plants incubated that night in the fanned house. The data suggest that nocturnal fanning is highly effective in suppressing downy mildew epidemics in sweet basil. Fanning prevented the within-canopy RH from reaching saturation, reduced dew deposition on the leaves, and hence prevented both infection and sporulation of P. belbahrii. PMID:27171554

Natural products as potential anticonvulsants: caffeoylquinic acids.

PubMed

Kim, Hyo Geun; Oh, Myung Sook

2012-03-01

Current anticonvulsant therapies are generally directed at symptomatic treatment by suppressing excitability within the brain. Consequently, they have adverse effects such as cognitive impairment, dependence, and abuse. The need for more effective and less toxic anticonvulsants has generated renewed interest in natural products for the treatment of convulsions. Caffeoylquinic acids (CQs) are naturally occurring phenolic acids that are distributed widely in plants. There has been increasing interest in the biological activities of CQs in diseases of the central nervous system. In this issue, Nugroho et al. give evidence for the anticonvulsive effect of a CQ-rich extract from Aster glehni Franchet et Sckmidt. They optimized the extract solvent conditions, resulting in high levels of CQs and peroxynitrite-scavenging activity. Then, they investigated the sedative and anticonvulsive effects in pentobarbital- and pentylenetetrazole-induced models in mice. The CQ-rich extract significantly inhibited tonic convulsions as assessed by onset time, tonic extent, and mortality. They suggested that the CQ-rich extract from A. glehni has potential for treating convulsions. This report provides preclinical data which may be used for the development of anticonvulsants from natural products.

Withaferin A suppresses the growth of myelodysplasia and leukemia cell lines by inhibiting cell cycle progression.

PubMed

Okamoto, Shuichiro; Tsujioka, Takayuki; Suemori, Shin-Ichiro; Kida, Jun-Ichiro; Kondo, Toshinori; Tohyama, Yumi; Tohyama, Kaoru

2016-09-01

Treatment outcomes for acute myeloid leukemia and myelodysplastic syndromes (MDS) remain unsatisfactory despite progress in various types of chemotherapy and hematopoietic stem cell transplantation. Therefore, there is a need for the development of new treatment options. We investigated the growth-suppressive effects of withaferin A (WA), a natural plant steroidal lactone, on myelodysplasia and leukemia cell lines. WA exhibited growth-suppressive effects on the cell lines, MDS-L, HL-60, THP-1, Jurkat and Ramos, and induction of cell cycle arrest at G2/M phase at relatively low doses. Evaluation by annexin V/PI also confirmed the induction of partial apoptosis. Gene expression profiling and subsequent gene set enrichment analysis revealed increased expression of heme oxygenase-1 (HMOX1). HMOX1 is known to induce autophagy during anticancer chemotherapy and is considered to be involved in the treatment resistance. Our study indicated increased HMOX1 protein levels and simultaneous increases in the autophagy-related protein LC3A/B in MDS-L cells treated with WA, suggesting increased autophagy. Combined use of WA with chloroquine, an autophagy inhibitor, enhanced early apoptosis and growth suppression. Together with the knowledge that WA had no apparent suppressive effect on the growth of human normal bone marrow CD34-positive cells in the short-term culture, this drug may have a potential for a novel therapeutic approach to the treatment of leukemia or MDS. © 2016 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

Species Diversity in Planted Pine and Natural Hardwoods 24 years After Sharing and Chipping on the Cumberland Plateau, TN

Treesearch

Karen Kuers

2002-01-01

Plant species richness in 24 year-old planted lobiolly pine (Pinus taeda L.), eastern white pine (Pinus strobus L.), yellow-poplar (Liriodendron tulipifera L.), naturally regenerated hardwoods, and mature hardwoods was compared using the North Carolina Vegetation Survey protocol. Comparisons were made in...

Linking wilderness research and management-volume 4. Understanding and managing invasive plants in wilderness and other natural areas: an annotated reading list

Treesearch

Sophie Osborn; Vita Wright; Brett Walker; Amy Cilimburg; Alison Perkins

2002-01-01

Nonnative invasive plants are altering ecosystems around the world with alarming speed. They outcompete native plants and ultimately change the composition and function of the ecosystems they invade. This poses a particular problem in wilderness and other natural areas that are set aside to maintain natural conditions. Wilderness managers are not only faced with the...

Xanthomonas campestris cell-cell signalling molecule DSF (diffusible signal factor) elicits innate immunity in plants and is suppressed by the exopolysaccharide xanthan.

PubMed

Kakkar, Akanksha; Nizampatnam, Narasimha Rao; Kondreddy, Anil; Pradhan, Binod Bihari; Chatterjee, Subhadeep

2015-11-01

Several secreted and surface-associated conserved microbial molecules are recognized by the host to mount the defence response. One such evolutionarily well-conserved bacterial process is the production of cell-cell signalling molecules which regulate production of multiple virulence functions by a process known as quorum sensing. Here it is shown that a bacterial fatty acid cell-cell signalling molecule, DSF (diffusible signal factor), elicits innate immunity in plants. The DSF family of signalling molecules are highly conserved among many phytopathogenic bacteria belonging to the genus Xanthomonas as well as in opportunistic animal pathogens. Using Arabidopsis, Nicotiana benthamiana, and rice as model systems, it is shown that DSF induces a hypersensitivity reaction (HR)-like response, programmed cell death, the accumulation of autofluorescent compounds, hydrogen peroxide production, and the expression of the PATHOGENESIS-RELATED1 (PR-1) gene. Furthermore, production of the DSF signalling molecule in Pseudomonas syringae, a non-DSF-producing plant pathogen, induces the innate immune response in the N. benthamiana host plant and also affects pathogen growth. By pre- and co-inoculation of DSF, it was demonstrated that the DSF-induced plant defence reduces disease severity and pathogen growth in the host plant. In this study, it was further demonstrated that wild-type Xanthomonas campestris suppresses the DSF-induced innate immunity by secreting xanthan, the main component of extracellular polysaccharide. The results indicate that plants have evolved to recognize a widely conserved bacterial communication system and may have played a role in the co-evolution of host recognition of the pathogen and the communication machinery. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Forest service large fire area burned and suppression expenditure trends, 1970-2002.

Treesearch

David E. Calkin; Krista M. Gebert; J. Greg Jones; Ronald P. Neilson

2005-01-01

Extreme fire seasons in recent years and associated high suppression expenditures have brought about a chorus of calls for reform of federal firefighting structure and policy. Given the political nature of the topic, a critical review of past trends in area burned, size of fires, and suppression expenditures is warranted. We examined data relating to emergency wildland...

Early development of matched planted and naturally regenerated Douglas-fir stands after slash burning in the Cascade Range.

Treesearch

R.E. Miller; R.E. Bigley; S. Webster

1993-01-01

We compared matched planted and naturally regenerated plots in 35- to 38- year-old Douglas-fir (Pseudotsuga menziesii var. menziesii) stands at seven locations in western Washington and Oregon. Total number of live stems is similar, but stands planted to Douglas fir average 26 more live stemslac of Douglas-fir and 39 fewer...

Restoration of native plant communities infested by invasive weeds -- Sawmill Creek Research Natural Area

Treesearch

Peter Rice

2000-01-01

Invasive alien weeds established themselves on the Sawmill Creek Research Natural Area, harming elk feeding grounds and threatening the integrity of the native plant community. Management enacted herbicide control over several growing seasons, resulting in greater elk winter forage on study plots. Monitoring the long-term effects of herbicide as a restoration tool...

Modeling of natural acoustic frequencies of a gas-turbine plant combustion chamber

NASA Astrophysics Data System (ADS)

Zubrilin, I. A.; Gurakov, N. I.; Zubrilin, R. A.; Matveev, S. G.

2017-05-01

The paper presents results of determination of natural acoustic frequencies of a gas-turbine plant annular combustion chamber model using 3D-simulation. At the beginning, a calculation procedure for determining natural acoustic frequencies of the gas-turbine plant combustion chamber was worked out. The effect of spatial inhomogeneity of the flow parameters (fluid composition, pressure, temperature) arising in combustion and some geometrical parameters (cooling holes of the flame tube walls) on the calculation results is studied. It is found that the change of the fluid composition in combustion affects the acoustic velocity not more than 5%; therefore, the air with a volume variable temperature can be taken as a working fluid in the calculation of natural acoustic frequencies. It is also shown that the cooling holes of the flame tube walls with diameter less than 2 mm can be neglected in the determination of the acoustic modes in the frequency range of up to 1000 Hz. This reduces the number of the grid-model elements by a factor of six in comparison with a model that considers all of the holes. Furthermore, a method of export of spatial inhomogeneity of the flow parameters from a CFD solver sector model to the annular combustion chamber model in a modal solver is presented. As a result of the obtained model calculation, acoustic modes of the combustion chamber in the frequency range of up to 1000 Hz are determined. For a standard engine condition, a potentially dangerous acoustic mode with a frequency close to the ripple frequency of the precessing vortex core, which is formed behind the burner device of this combustion chamber, is detected.

Wild plant folk nomenclature of the Mongol herdsmen in the Arhorchin National Nature Reserve, Inner Mongolia, PR China.

PubMed

Soyolt; Galsannorbu; Yongping; Wunenbayar; Liu, Guohou; Khasbagan

2013-04-24

Folk names of plants are the root of traditional plant biodiversity knowledge. In pace with social change and economic development, Mongolian knowledge concerning plant diversity is gradually vanishing. Collection and analysis of Mongolian folk names of plants is extremely important. During 2008 to 2012, the authors have been to the Arhorchin National Nature Reserve area 5 times. Fieldwork was done in 13 villages, with 56 local Mongol herdsmen being interviewed. This report documents plant folk names, analyzes the relationship between folk names and scientific names, looks at the structure and special characteristics of folk names, plant use information, and comparative analysis were also improved. Ethnobotanical interviewing methods of free-listing and open-ended questionnaires were used. Ethnobotanical interview and voucher specimen collection were carried out in two ways as local plant specimens were collected beforehand and then used in interviews, and local Mongol herdsmen were invited to the field and interviewed while collecting voucher specimens. Mongolian oral language was used as the working language and findings were originally recorded in Mongolian written language. Scientific names of plants are defined through collection and identification of voucher specimens by the methods of plant taxonomy. A total of 146 folk names of local plants are recorded. Plant folk names corresponded with 111 species, 1 subspecies, 7 varieties, 1 form, which belong to 42 families and 88 genera. The correspondence between plant folk names and scientific names may be classified as one to one correspondence, two or three to one correspondence, and one to multitude correspondence. The structure of folk names were classified as primary names, secondary names and borrowed names. There were 12 folk names that contain animal names and they have correspondence with 15 species. There are nine folk names that contain usage information and they have correspondence with 10 species in

Food plant derived disease tolerance and resistance in a natural butterfly-plant-parasite interactions.

PubMed

Sternberg, Eleanore D; Lefèvre, Thierry; Li, James; de Castillejo, Carlos Lopez Fernandez; Li, Hui; Hunter, Mark D; de Roode, Jacobus C

2012-11-01

Organisms can protect themselves against parasite-induced fitness costs through resistance or tolerance. Resistance includes mechanisms that prevent infection or limit parasite growth while tolerance alleviates the fitness costs from parasitism without limiting infection. Although tolerance and resistance affect host-parasite coevolution in fundamentally different ways, tolerance has often been ignored in animal-parasite systems. Where it has been studied, tolerance has been assumed to be a genetic mechanism, unaffected by the host environment. Here we studied the effects of host ecology on tolerance and resistance to infection by rearing monarch butterflies on 12 different species of milkweed food plants and infecting them with a naturally occurring protozoan parasite. Our results show that monarch butterflies experience different levels of tolerance to parasitism depending on the species of milkweed that they feed on, with some species providing over twofold greater tolerance than other milkweed species. Resistance was also affected by milkweed species, but there was no relationship between milkweed-conferred resistance and tolerance. Chemical analysis suggests that infected monarchs obtain highest fitness when reared on milkweeds with an intermediate concentration, diversity, and polarity of toxic secondary plant chemicals known as cardenolides. Our results demonstrate that environmental factors-such as interacting species in ecological food webs-are important drivers of disease tolerance. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

Herbaceous plant species invading natural areas tend to have stronger adaptive root foraging than other naturalized species

PubMed Central

Keser, Lidewij H.; Visser, Eric J. W.; Dawson, Wayne; Song, Yao-Bin; Yu, Fei-Hai; Fischer, Markus; Dong, Ming; van Kleunen, Mark

2015-01-01

Although plastic root-foraging responses are thought to be adaptive, as they may optimize nutrient capture of plants, this has rarely been tested. We investigated whether nutrient-foraging responses are adaptive, and whether they pre-adapt alien species to become natural-area invaders. We grew 12 pairs of congeneric species (i.e., 24 species) native to Europe in heterogeneous and homogeneous nutrient environments, and compared their foraging responses and performance. One species in each pair is a USA natural-area invader, and the other one is not. Within species, individuals with strong foraging responses, measured as plasticity in root diameter and specific root length, had a higher biomass. Among species, the ones with strong foraging responses, measured as plasticity in root length and root biomass, had a higher biomass. Our results therefore suggest that root foraging is an adaptive trait. Invasive species showed significantly stronger root-foraging responses than non-invasive species when measured as root diameter. Biomass accumulation was decreased in the heterogeneous vs. the homogeneous environment. In aboveground, but not belowground and total biomass, this decrease was smaller in invasive than in non-invasive species. Our results show that strong plastic root-foraging responses are adaptive, and suggest that it might aid in pre-adapting species to becoming natural-area invaders. PMID:25964790

Plant–plant interactions mediate the plastic and genotypic response of Plantago asiatica to CO2: an experiment with plant populations from naturally high CO2 areas

PubMed Central

van Loon, Marloes P.; Rietkerk, Max; Dekker, Stefan C.; Hikosaka, Kouki; Ueda, Miki U.; Anten, Niels P. R.

2016-01-01

Background and Aims The rising atmospheric CO2 concentration ([CO2]) is a ubiquitous selective force that may strongly impact species distribution and vegetation functioning. Plant–plant interactions could mediate the trajectory of vegetation responses to elevated [CO2], because some plants may benefit more from [CO2] elevation than others. The relative contribution of plastic (within the plant’s lifetime) and genotypic (over several generations) responses to elevated [CO2] on plant performance was investigated and how these patterns are modified by plant–plant interactions was analysed. Methods Plantago asiatica seeds originating from natural CO2 springs and from ambient [CO2] sites were grown in mono stands of each one of the two origins as well as mixtures of both origins. In total, 1944 plants were grown in [CO2]-controlled walk-in climate rooms, under a [CO2] of 270, 450 and 750 ppm. A model was used for upscaling from leaf to whole-plant photosynthesis and for quantifying the influence of plastic and genotypic responses. Key Results It was shown that changes in canopy photosynthesis, specific leaf area (SLA) and stomatal conductance in response to changes in growth [CO2] were mainly determined by plastic and not by genotypic responses. We further found that plants originating from high [CO2] habitats performed better in terms of whole-plant photosynthesis, biomass and leaf area, than those from ambient [CO2] habitats at elevated [CO2] only when both genotypes competed. Similarly, plants from ambient [CO2] habitats performed better at low [CO2], also only when both genotypes competed. No difference in performance was found in mono stands. Conclusion The results indicate that natural selection under increasing [CO2] will be mainly driven by competitive interactions. This supports the notion that plant–plant interactions have an important influence on future vegetation functioning and species distribution. Furthermore, plant performance was mainly

The polychlorinated dibenzofuran fingerprint of iron ore sinter plant: Its persistence with suppressant and alternative fuel addition.

PubMed

Thompson, Dennis; Ooi, Tze C; Anderson, David R; Fisher, Ray; Ewan, Bruce C R

2016-07-01

An earlier demonstration that the relative concentrations of isomers of polychlorinated dibenzofuran do not vary as the flamefront of an iron ore sinter plant progresses through the bed, and profiles are similar for two sinter strands has been widened to include studies of the similarity or otherwise between full scale strand and sinter pot profiles, effect of addition of suppressants and of coke fuel substitution with other combustible materials. For dioxin suppressant addition, a study of the whole of the tetra- penta- and hexaCDF isomer range as separated by the DB5MS chromatography column, indicates no significant change in profile: examination of the ratios of the targeted penta- and hexaCDF isomers suggests the profile is similarly unaffected by coke fuel replacement. Addition of KCl at varied levels has also been shown to have no effect on the 'fingerprint' and there is no indication of any effect by the composition of the sinter mix. The recently published full elution sequence for the DB5MS column is applied to the results obtained using this column. It is confirmed that isomers with 1,9-substitution of chlorine atoms are invariably formed in low concentrations. This is consistent with strong interaction between the 1 and 9 substituted chlorine atoms predicted by DFT thermodynamic calculations. Non-1,9-substituted PCDF equilibrium isomer distributions based on DFT-derived thermodynamic data differ considerably from stack gas distributions obtained using SP2331 column separation. A brief preliminary study indicates the same conclusions (apart from the 1,9-interaction effect) hold for the much smaller content of PCDD. Copyright © 2016 Elsevier Ltd. All rights reserved.

Suppression of Collisionless Magnetic Reconnection in Asymmetric Current Sheets

NASA Technical Reports Server (NTRS)

Liu, Yi-Hsin; Hesse, Michael

2016-01-01

Using fully kinetic simulations, we study the suppression of asymmetric reconnection in the limit where the diamagnetic drift speed >> Alfven speed and the magnetic shear angle is moderate. We demonstrate that the slippage between electrons and the magnetic flux mitigates the suppression and can even result in fast reconnection that lacks one of the outflow jets. Through comparing a case where the diamagnetic drift is supported by the temperature gradient with a companion case that has a density gradient instead, we identify a robust suppression mechanism. The drift of the x-line is slowed down locally by the asymmetric nature of the x-line, and then the x-line is run over and swallowed by the faster-moving following flux.

Plant Innate Immunity Induced by Flagellin Suppresses the Hypersensitive Response in Non-Host Plants Elicited by Pseudomonas syringae pv. averrhoi

PubMed Central

Wei, Chia-Fong; Hsu, Shih-Tien; Deng, Wen-Ling; Wen, Yu-Der; Huang, Hsiou-Chen

2012-01-01

A new pathogen, Pseudomonas syringae pv. averrhoi (Pav), which causes bacterial spot disease on carambola was identified in Taiwan in 1997. Many strains of this pathovar have been isolated from different locations and several varieties of hosts. Some of these strains, such as HL1, are nonmotile and elicit a strong hypersensitive response (HR) in nonhost tobacco leaves, while other strains, such as PA5, are motile and elicit a weak HR. Based on the image from a transmission electron microscope, the results showed that HL1 is flagellum-deficient and PA5 has normal flagella. Here we cloned and analyzed the fliC gene and glycosylation island from Pav HL1 and PA5. The amino acid sequences of FliC from HL1 and PA5 are identical to P. s. pvs. tabaci (Pta), glycinea and phaseolicola and share very high similarity with other pathovars of P. syringae. In contrast to the flagellin mutant PtaΔfliC, PA5ΔfliC grows as well as wild type in the host plant, but it elicits stronger HR than wild type does in non-host plants. Furthermore, the purified Pav flagellin, but not the divergent flagellin from Agrobacterium tumefaciens, is able to impair the HR induced by PA5ΔfliC. PA5Δfgt1 possessing nonglycosylated flagella behaved as its wild type in both bacterial growth in host and HR elicitation. Flagellin was infiltrated into tobacco leaves either simultaneously with flagellum-deficient HL1 or prior to the inoculation of wild type HL1, and both treatments impaired the HR induced by HL1. Moreover, the HR elicited by PA5 and PA5ΔfliC was enhanced by the addition of cycloheximide, suggesting that the flagellin is one of the PAMPs (pathogen-associated molecular patterns) contributed to induce the PAMP-triggered immunity (PTI). Taken together, the results shown in this study reveal that flagellin in Pav is capable of suppressing HR via PTI induction during an incompatible interaction. PMID:22911741

Plant innate immunity induced by flagellin suppresses the hypersensitive response in non-host plants elicited by Pseudomonas syringae pv. averrhoi.

PubMed

Wei, Chia-Fong; Hsu, Shih-Tien; Deng, Wen-Ling; Wen, Yu-Der; Huang, Hsiou-Chen

2012-01-01

A new pathogen, Pseudomonas syringae pv. averrhoi (Pav), which causes bacterial spot disease on carambola was identified in Taiwan in 1997. Many strains of this pathovar have been isolated from different locations and several varieties of hosts. Some of these strains, such as HL1, are nonmotile and elicit a strong hypersensitive response (HR) in nonhost tobacco leaves, while other strains, such as PA5, are motile and elicit a weak HR. Based on the image from a transmission electron microscope, the results showed that HL1 is flagellum-deficient and PA5 has normal flagella. Here we cloned and analyzed the fliC gene and glycosylation island from Pav HL1 and PA5. The amino acid sequences of FliC from HL1 and PA5 are identical to P. s. pvs. tabaci (Pta), glycinea and phaseolicola and share very high similarity with other pathovars of P. syringae. In contrast to the flagellin mutant PtaΔfliC, PA5ΔfliC grows as well as wild type in the host plant, but it elicits stronger HR than wild type does in non-host plants. Furthermore, the purified Pav flagellin, but not the divergent flagellin from Agrobacterium tumefaciens, is able to impair the HR induced by PA5ΔfliC. PA5Δfgt1 possessing nonglycosylated flagella behaved as its wild type in both bacterial growth in host and HR elicitation. Flagellin was infiltrated into tobacco leaves either simultaneously with flagellum-deficient HL1 or prior to the inoculation of wild type HL1, and both treatments impaired the HR induced by HL1. Moreover, the HR elicited by PA5 and PA5ΔfliC was enhanced by the addition of cycloheximide, suggesting that the flagellin is one of the PAMPs (pathogen-associated molecular patterns) contributed to induce the PAMP-triggered immunity (PTI). Taken together, the results shown in this study reveal that flagellin in Pav is capable of suppressing HR via PTI induction during an incompatible interaction.

The enrichment behavior of natural radionuclides in pulverized oil shale-fired power plants.

PubMed

Vaasma, Taavi; Kiisk, Madis; Meriste, Tõnis; Tkaczyk, Alan Henry

2014-12-01

The oil shale industry is the largest producer of NORM (Naturally Occurring Radioactive Material) waste in Estonia. Approximately 11-12 million tons of oil shale containing various amounts of natural radionuclides is burned annually in the Narva oil shale-fired power plants, which accounts for approximately 90% of Estonian electricity production. The radionuclide behavior characteristics change during the fuel combustion process, which redistributes the radionuclides between different ash fractions. Out of 24 operational boilers in the power plants, four use circulating fluidized bed (CFB) technology and twenty use pulverized fuel (PF) technology. Over the past decade, the PF boilers have been renovated, with the main objective to increase the efficiency of the filter systems. Between 2009 and 2012, electrostatic precipitators (ESP) in four PF energy blocks were replaced with novel integrated desulphurization technology (NID) for the efficient removal of fly ash and SO2 from flue gases. Using gamma spectrometry, activity concentrations and enrichment factors for the (238)U ((238)U, (226)Ra, (210)Pb) and (232)Th ((232)Th, (228)Ra) family radionuclides as well as (40)K were measured and analyzed in different PF boiler ash fractions. The radionuclide activity concentrations in the ash samples increased from the furnace toward the back end of the flue gas duct. The highest values in different PF boiler ash fractions were in the last field of the ESP and in the NID ash, where radionuclide enrichment factors were up to 4.2 and 3.3, respectively. The acquired and analyzed data on radionuclide activity concentrations in different PF boiler ashes (operating with an ESP and a NID system) compared to CFB boiler ashes provides an indication that changes in the fuel (oil shale) composition and boiler working parameters, as well as technological enhancements in Estonian oil shale fired power plants, have had a combined effect on the distribution patterns of natural radionuclides

Phylogeny, plant species, and plant diversity influence carbon use phenotypes among Fusarium populations in the rhizosphere microbiome

USDA-ARS?s Scientific Manuscript database

Carbon use by microorganisms in the rhizosphere microbiome has been linked to plant pathogen suppression and increased mineralization of soil nutrients for plant uptake, however factors that influence carbon use traits are poorly understood for most microbial groups. This work characterized the rela...

Exploring the nature of science through courage and purpose: a case study of Nikolai Vavilov and plant biodiversity.

PubMed

Cohen, Joel I; Loskutov, Igor G

2016-01-01

Historical biographies facilitate teaching the 'nature of science'. This case study focuses on how Nikolai Vavilov's unrelenting sense of purpose, courage, and charismatic personality was maintained during violent revolutionary change in Russia. The rediscovery of Gregor Mendel's laws of inheritance provided Vavilov with a scientific foundation for crop improvement, this foundation was later bolstered by Vavilov's personal drive to conserve plant biodiversity. As he advanced theories and pragmatic approaches for genetic improvement and conservation of plants, political leaders in Russian came to reject Mendel's principles and eventually Vavilov's work. This rejection occurred because Joseph Stalin was desperate for a quick remedy to the famine and suffering from forced collective agriculture. Vavilov's work continued, modernizing Russian crop research while inspiring other scientists to save seeds stored in the world's first gene bank. Three themes illustrating the nature of science help examine Vavilov's life: explaining natural phenomena, uncompromising human endeavor, and revising scientific knowledge. The case study concludes with four questions to stimulate student inquiry and self-guided research. They also deepen student understanding of Vavilov's personal sacrifices to ensure use and conservation of plant biodiversity.

Design and test of three active flutter suppression controllers

NASA Technical Reports Server (NTRS)

Christhilf, David M.; Waszak, Martin R.; Adams, William M.; Srinathkumar, S.; Mukhopadhyay, Vivek

1991-01-01

Three flutter suppression control law design techniques are presented. Each uses multiple control surfaces and/or sensors. The first uses linear combinations of several accelerometer signals together with dynamic compensation to synthesize the modal rate of the critical mode for feedback to distributed control surfaces. The second uses traditional tools (pole/zero loci and Nyquist diagrams) to develop a good understanding of the flutter mechanism and produce a controller with minimal complexity and good robustness to plant uncertainty. The third starts with a minimum energy Linear Quadratic Gaussian controller, applies controller order reduction, and then modifies weight and noise covariance matrices to improve multi-variable robustness. The resulting designs were implemented digitally and tested subsonically on the Active Flexible Wing (AFW) wind tunnel model. Test results presented here include plant characteristics, maximum attained closed-loop dynamic pressure, and Root Mean Square control surface activity. A key result is that simultaneous symmetric and antisymmetric flutter suppression was achieved by the second control law, with a 24 percent increase in attainable dynamic pressure.

Comparing the plant diversity between artificial forest and nature growth forest in a giant panda habitat.

PubMed

Kang, Dongwei; Wang, Xiaorong; Li, Shuang; Li, Junqing

2017-06-15

Artificial restoration is an important way to restore forests, but little is known about its effect on the habitat restoration of the giant panda. In the present study, we investigated the characteristics of artificial forest in the Wanglang Nature Reserve to determine whether through succession it has formed a suitable habitat for the giant panda. We compared artificial forest characteristics with those of natural habitat used by the giant panda. We found that the dominant tree species in artificial forest differed from those in the natural habitat. The artificial forest had lower plant species richness and diversity in the tree and shrub layers than did the latter, and its community structure was characterized by smaller tree and bamboo sizes, and fewer and lower bamboo clumps, but more trees and larger shrub sizes. The typical community collocation of artificial forest was a "Picea asperata + no-bamboo" model, which differs starkly from the giant panda's natural habitat. After several years of restoration, the artificial forest has failed to become a suitable habitat for the giant panda. Therefore, a simple way of planting individual trees cannot restore giant panda habitat; instead, habitat restoration should be based on the habitat requirements of the giant panda.

Mercury uptake and phytotoxicity in terrestrial plants grown naturally in the Gumuskoy (Kutahya) mining area, Turkey.

PubMed

Sasmaz, Merve; Akgül, Bunyamin; Yıldırım, Derya; Sasmaz, Ahmet

2016-01-01

This study investigated mercury (Hg) uptake and transport from the soil to different plant parts by documenting the distribution and accumulation of Hg in the roots and shoots of 12 terrestrial plant species, all of which grow naturally in surface soils of the Gumuskoy Pb-Ag mining area. Plant samples and their associated soils were collected and analyzed for Hg content by ICP-MS. Mean Hg values in the soils, roots, and shoots of all plants were 6.914, 460, and 206 µg kg(-1), respectively and lower than 1. The mean enrichment factors for the roots (ECR) and shoots (ECS) of these plants were 0.06 and 0.09, respectively and lower than 1. These results show that the roots of the studied plants prevented Hg from reaching the aerial parts of the plants. The mean translocation factor (TLF) was 1.29 and higher than 1. The mean TLF values indicated that all 12 plant species had the ability to transfer Hg from the roots to the shoots but that transfer was more efficient in plants with higher ECR and ECS. Therefore, these plants could be useful for the biomonitoring of environmental pollution and for rehabilitating areas contaminated by Hg.

Strigolactones suppress adventitious rooting in Arabidopsis and pea.

PubMed

Rasmussen, Amanda; Mason, Michael Glenn; De Cuyper, Carolien; Brewer, Philip B; Herold, Silvia; Agusti, Javier; Geelen, Danny; Greb, Thomas; Goormachtig, Sofie; Beeckman, Tom; Beveridge, Christine Anne

2012-04-01

Adventitious root formation is essential for the propagation of many commercially important plant species and involves the formation of roots from nonroot tissues such as stems or leaves. Here, we demonstrate that the plant hormone strigolactone suppresses adventitious root formation in Arabidopsis (Arabidopsis thaliana) and pea (Pisum sativum). Strigolactone-deficient and response mutants of both species have enhanced adventitious rooting. CYCLIN B1 expression, an early marker for the initiation of adventitious root primordia in Arabidopsis, is enhanced in more axillary growth2 (max2), a strigolactone response mutant, suggesting that strigolactones restrain the number of adventitious roots by inhibiting the very first formative divisions of the founder cells. Strigolactones and cytokinins appear to act independently to suppress adventitious rooting, as cytokinin mutants are strigolactone responsive and strigolactone mutants are cytokinin responsive. In contrast, the interaction between the strigolactone and auxin signaling pathways in regulating adventitious rooting appears to be more complex. Strigolactone can at least partially revert the stimulatory effect of auxin on adventitious rooting, and auxin can further increase the number of adventitious roots in max mutants. We present a model depicting the interaction of strigolactones, cytokinins, and auxin in regulating adventitious root formation.

Plant leaves as natural green scaffolds for palladium catalyzed Suzuki-Miyaura coupling reactions.

PubMed

Sharma, Vipul; Kumar, Suneel; Bahuguna, Ashish; Gambhir, Diksha; Sagara, Prateep Singh; Krishnan, Venkata

2016-12-21

This work presents a novel approach of using natural plant leaf surfaces having intricate hierarchical structures as scaffolds for Pd nanoparticles and demonstrated it as a Green dip catalyst for Suzuki-Miyaura coupling reactions in water. The influence of the topographical texture of the plant leaves on the deposition and catalytic properties of Pd nanoparticles are presented and discussed. The catalytic activity can be correlated to the surface texture of the leaves, wherein it has been found that the micro/nanostructures present on the surface strongly influence the assembly and entrapment of the nanoparticles, and thereby control aggregation and leaching of the catalysts. This approach can provide insights for the future design and fabrication of bioinspired supports for catalysis, based on replication of leaf surfaces.

Land-use legacies and present fire regimes interact to mediate herbivory by altering the neighboring plant community

DOE PAGES

Hahn, Philip G.; Orrock, John L.

2014-10-03

Past and present human activities, such as historic agriculture and fire suppression, are widespread and can create depauperate plant communities. Although many studies show that herbivory on focal plants depends on the density of herbivores or the composition of the surrounding plant community, it is unclear whether anthropogenic changes to plant communities alter herbivory. We tested the hypothesis that human activities that alter the plant community lead to subsequent changes in herbivory. At 20 sites distributed across 80 300 hectares, we conducted a field experiment that manipulated insect herbivore access (full exclosures and pseudo-exclosures) to four focal plant species inmore » longleaf pine woodlands with diff erent land-use histories (post-agricultural sites or non-agricultural sites) and degrees of fi re frequency (frequent and infrequent). Plant cover, particularly herbaceous cover, was lower in post-agricultural and fi re suppressed woodlands. Density of the dominant insect herbivore at our site (grasshoppers) was positively related to plant cover. Herbivore access reduced biomass of the palatable forb Solidago odora in frequently burned post-agricultural sites and in infrequently burned non-agricultural woodlands and increased mortality of another forb (Pityopsis graminifolia ), but did not aff ect two other less palatable species ( Schizachyrium scoparium and Tephrosia virginiana ). Herbivory on S. odora exhibited a hump-shaped response to plant cover, with low herbivory at low and high levels of plant cover. Herbivore density had a weak negative effect on herbivory. These findings suggest that changes in plant cover related to past and present human activities can modify damage rates on focal S. odora plants by altering grasshopper foraging behavior rather than by altering local grasshopper density. The resulting changes in herbivory may have the potential to limit natural recovery or restoration eff orts by reducing the establishment or

Land-use legacies and present fire regimes interact to mediate herbivory by altering the neighboring plant community

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

Hahn, Philip G.; Orrock, John L.

Past and present human activities, such as historic agriculture and fire suppression, are widespread and can create depauperate plant communities. Although many studies show that herbivory on focal plants depends on the density of herbivores or the composition of the surrounding plant community, it is unclear whether anthropogenic changes to plant communities alter herbivory. We tested the hypothesis that human activities that alter the plant community lead to subsequent changes in herbivory. At 20 sites distributed across 80 300 hectares, we conducted a field experiment that manipulated insect herbivore access (full exclosures and pseudo-exclosures) to four focal plant species inmore » longleaf pine woodlands with diff erent land-use histories (post-agricultural sites or non-agricultural sites) and degrees of fi re frequency (frequent and infrequent). Plant cover, particularly herbaceous cover, was lower in post-agricultural and fi re suppressed woodlands. Density of the dominant insect herbivore at our site (grasshoppers) was positively related to plant cover. Herbivore access reduced biomass of the palatable forb Solidago odora in frequently burned post-agricultural sites and in infrequently burned non-agricultural woodlands and increased mortality of another forb (Pityopsis graminifolia ), but did not aff ect two other less palatable species ( Schizachyrium scoparium and Tephrosia virginiana ). Herbivory on S. odora exhibited a hump-shaped response to plant cover, with low herbivory at low and high levels of plant cover. Herbivore density had a weak negative effect on herbivory. These findings suggest that changes in plant cover related to past and present human activities can modify damage rates on focal S. odora plants by altering grasshopper foraging behavior rather than by altering local grasshopper density. The resulting changes in herbivory may have the potential to limit natural recovery or restoration eff orts by reducing the establishment or

The potential role of natural gas power plants with carbon capture and storage as a bridge to a low-carbon future

EPA Science Inventory

The CO2 intensity of electricity produced by state-of-the-art natural gas combined-cycle turbines (NGCC) is approximately one-third that of the U.S. fleet of existing coal plants. Compared to new nuclear plants and coal plants with integrated carbon capture, NGCC has a lower inve...

Relationship between humanity and plant natural resources – in the context of food and agriculture

USDA-ARS?s Scientific Manuscript database

Agriculture, the domestication, culture, and management of plants and animals, has led to profound social changes in human evolution and development; it can be considered as the basis for civilization. Roughly 12,000 years ago agriculture appeared independently in several parts of the world. A natur...

Gathering “tea” – from necessity to connectedness with nature. Local knowledge about wild plant gathering in the Biosphere Reserve Grosses Walsertal (Austria)

PubMed Central

2012-01-01

Background Wild plant gathering is an essential element in livelihood strategies all over the world. However due to changing circumstances in Europe, the reason for gathering has altered from one of necessity in the past to a pleasurable activity today. Wild plant gathering has therefore also received renewed attention as a form of intangible cultural heritage expressing local preferences, habits and man’s relationship with nature. In the Biosphere Reserve Grosses Walsertal (Austria), local people’s knowledge of the gathering of wild plants and their perception of their own gathering activities are being documented. The focus of this paper is on the uses of herbal teas and the informal guidelines for gathering plants that have been issued by the Bergtee (mountain tea) association. Methods Thirty-six free-list interviews were conducted with subsequent semi-structured interviews and three focus group meetings held with members of the Bergtee association. Participatory observation (gathering and processing plants, mixing and marketing tea) also allowed for greater understanding of what had been reported. Results In total, 140 different gathered plant species were listed by respondents. Herbal tea is the most frequently mentioned use. The Bergtee association, founded by a young man and two middle-aged women in the valley, is a good example of the link between biological and cultural diversity, with the aim of sharing the biosphere reserve’s natural treasures as well as local plant-related knowledge in the form of herbal tea products. The association’s informal guidelines for gathering reflect people’s attitude to nature: monetary income does not play a major role in gathering plants; instead people’s appreciation of the value of the nature around them is to the fore. Conclusions Gathering wild plants can be seen as an expression of people’s regional identity. The conscious appreciation of nature and related local knowledge is crucial for the sustainable

Direct quantitative evaluation of disease symptoms on living plant leaves growing under natural light.

PubMed

Matsunaga, Tomoko M; Ogawa, Daisuke; Taguchi-Shiobara, Fumio; Ishimoto, Masao; Matsunaga, Sachihiro; Habu, Yoshiki

2017-06-01

Leaf color is an important indicator when evaluating plant growth and responses to biotic/abiotic stress. Acquisition of images by digital cameras allows analysis and long-term storage of the acquired images. However, under field conditions, where light intensity can fluctuate and other factors (shade, reflection, and background, etc.) vary, stable and reproducible measurement and quantification of leaf color are hard to achieve. Digital scanners provide fixed conditions for obtaining image data, allowing stable and reliable comparison among samples, but require detached plant materials to capture images, and the destructive processes involved often induce deformation of plant materials (curled leaves and faded colors, etc.). In this study, by using a lightweight digital scanner connected to a mobile computer, we obtained digital image data from intact plant leaves grown in natural-light greenhouses without detaching the targets. We took images of soybean leaves infected by Xanthomonas campestris pv. glycines , and distinctively quantified two disease symptoms (brown lesions and yellow halos) using freely available image processing software. The image data were amenable to quantitative and statistical analyses, allowing precise and objective evaluation of disease resistance.

Antitumor-promoting activity of scopadulcic acid B, isolated from the medicinal plant Scoparia dulcis L.

PubMed

Nishino, H; Hayashi, T; Arisawa, M; Satomi, Y; Iwashima, A

1993-01-01

Scopadulcic acid B (SDB), a tetracyclic diterpenoid isolated from a medicinal plant, Scoparia dulcis L., inhibited the effects of tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) in vitro and in vivo; SDB inhibited TPA-enhanced phospholipid synthesis in cultured cells, and also suppressed the promoting effect of TPA on skin tumor formation in mice initiated with 7,12-dimethylbenz[a]anthracene. The potency of SDB proved to be stronger than that of other natural antitumor-promoting terpenoids, such as glycyrrhetinic acid.

A Maize Cystatin Suppresses Host Immunity by Inhibiting Apoplastic Cysteine Proteases[C][W

PubMed Central

van der Linde, Karina; Hemetsberger, Christoph; Kastner, Christine; Kaschani, Farnusch; van der Hoorn, Renier A.L.; Kumlehn, Jochen; Doehlemann, Gunther

2012-01-01

Ustilago maydis is a biotrophic pathogen causing maize (Zea mays) smut disease. Transcriptome profiling of infected maize plants indicated that a gene encoding a putative cystatin (CC9) is induced upon penetration by U. maydis wild type. By contrast, cc9 is not induced after infection with the U. maydis effector mutant Δpep1, which elicits massive plant defenses. Silencing of cc9 resulted in a strongly induced maize defense gene expression and a hypersensitive response to U. maydis wild-type infection. Consequently, fungal colonization was strongly reduced in cc9-silenced plants, while recombinant CC9 prevented salicylic acid (SA)–induced defenses. Protease activity profiling revealed a strong induction of maize Cys proteases in SA-treated leaves, which could be inhibited by addition of CC9. Transgenic maize plants overexpressing cc9-mCherry showed an apoplastic localization of CC9. The transgenic plants showed a block in Cys protease activity and SA-dependent gene expression. Moreover, activated apoplastic Cys proteases induced SA-associated defense gene expression in naïve plants, which could be suppressed by CC9. We show that apoplastic Cys proteases play a pivotal role in maize defense signaling. Moreover, we identified cystatin CC9 as a novel compatibility factor that suppresses Cys protease activity to allow biotrophic interaction of maize with the fungal pathogen U. maydis. PMID:22454455

No hormone to rule them all: Interactions of plant hormones during the responses of plants to pathogens.

PubMed

Shigenaga, Alexandra M; Argueso, Cristiana T

2016-08-01

Plant hormones are essential regulators of plant growth and immunity. In the last few decades, a vast amount of information has been obtained detailing the role of different plant hormones in immunity, and how they work together to ultimately shape the outcomes of plant pathogen interactions. Here we provide an overview on the roles of the main classes of plant hormones in the regulation of plant immunity, highlighting their metabolic and signaling pathways and how plants and pathogens utilize these pathways to activate or suppress defence. Copyright © 2016 Elsevier Ltd. All rights reserved.

33 CFR 149.416 - What are the requirements for a dry chemical fire suppression system?

Code of Federal Regulations, 2010 CFR

2010-07-01

... the requirements for a dry chemical fire suppression system? Each natural gas deepwater port must be... dry chemical fire suppression system? 149.416 Section 149.416 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DEEPWATER PORTS DEEPWATER PORTS: DESIGN, CONSTRUCTION...

Changing High School Students' Conceptions of the Nature of Science: The Partnership for Research and Education in Plants (PREP)

ERIC Educational Resources Information Center

Brooks, Eric Dwayne

2011-01-01

This study investigated whether participation in the Partnership for Research and Education in Plants (PREP), a long-term authentic plant research project, in conjunction with explicit verses implicit instruction can change high school students' conceptions of the nature of science (NOS). The participants included a total of 134 students comprised…

Fuel age and fire spread: Natural conditions versus opportunities for fire suppression

USGS Publications Warehouse

Halsey, Richard W.; Keeley, Jon E.; Wilson, Kit

2009-01-01

Wildfires are driven and restrained by an interplay of variables that can lead to many potential outcomes. As every wildland firefighter learns in basic training, the ability of a fire to spread is determined by three basic variables: fuel type and condition, weather, and topography. Fire suppression obviously plays a significant role in determining fire spread as well, so firefighter activity becomes an additional variable.

Thermodynamic model effects on the design and optimization of natural gas plants

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

Diaz, S.; Zabaloy, M.; Brignole, E.A.

1999-07-01

The design and optimization of natural gas plants is carried out on the basis of process simulators. The physical property package is generally based on cubic equations of state. By rigorous thermodynamics phase equilibrium conditions, thermodynamic functions, equilibrium phase separations, work and heat are computed. The aim of this work is to analyze the NGL turboexpansion process and identify possible process computations that are more sensitive to model predictions accuracy. Three equations of state, PR, SRK and Peneloux modification, are used to study the effect of property predictions on process calculations and plant optimization. It is shown that turboexpander plantsmore » have moderate sensitivity with respect to phase equilibrium computations, but higher accuracy is required for the prediction of enthalpy and turboexpansion work. The effect of modeling CO{sub 2} solubility is also critical in mixtures with high CO{sub 2} content in the feed.« less

Suppression of the root-knot nematode [Meloidogyne incognita (Kofoid & White) Chitwood] on tomato by dual inoculation with arbuscular mycorrhizal fungi and plant growth-promoting rhizobacteria.

PubMed

Liu, Runjin; Dai, Mei; Wu, Xia; Li, Min; Liu, Xingzhong

2012-05-01

Arbuscular mycorrhizal (AM) fungi and plant growth-promoting rhizobacteria (PGPR) have potential for the biocontrol of soil-borne diseases. The objectives of this study were to quantify the interactions between AM fungi [Glomus versiforme (Karsten) Berch and Glomus mosseae (Nicol. & Gerd.) Gerdemann & Trappe] and PGPR [Bacillus polymyxa (Prazmowski) Mace and Bacillus sp.] during colonization of roots and rhizosphere of tomato (Lycopersicon esculentum Mill) plants (cultivar Jinguan), and to determine their combined effects on the root-knot nematode, Meloidogyne incognita, and on tomato growth. Three greenhouse experiments were conducted. PGPR increased colonization of roots by AM fungi, and AM fungi increased numbers of PGPR in the rhizosphere. Dual inoculations of AM fungi plus PGPR provided greater control of M. incognita and greater promotion of plant growth than single inoculations, and the best combination was G. mosseae plus Bacillus sp. The results indicate that specific AM fungi and PGPR can stimulate each other and that specific combinations of AM fungi and PGPR can interact to suppress M. incognita and disease development. © Springer-Verlag 2012

Plant centromere organization: a dynamic structure with conserved functions.

PubMed

Ma, Jianxin; Wing, Rod A; Bennetzen, Jeffrey L; Jackson, Scott A

2007-03-01

Although the structural features of centromeres from most multicellular eukaryotes remain to be characterized, recent analyses of the complete sequences of two centromeric regions of rice, together with data from Arabidopsis thaliana and maize, have illuminated the considerable size variation and sequence divergence of plant centromeres. Despite the severe suppression of meiotic chromosomal exchange in centromeric and pericentromeric regions of rice, the centromere core shows high rates of unequal homologous recombination in the absence of chromosomal exchange, resulting in frequent and extensive DNA rearrangement. Not only is the sequence of centromeric tandem and non-tandem repeats highly variable but also the copy number, spacing, order and orientation, providing ample natural variation as the basis for selection of superior centromere performance. This review article focuses on the structural and evolutionary dynamics of plant centromere organization and the potential molecular mechanisms responsible for the rapid changes of centromeric components.

Suppression of overt attentional capture by salient-but-irrelevant color singletons.

PubMed

Gaspelin, Nicholas; Leonard, Carly J; Luck, Steven J

2017-01-01

For more than 2 decades, researchers have debated the nature of cognitive control in the guidance of visual attention. Stimulus-driven theories claim that salient stimuli automatically capture attention, whereas goal-driven theories propose that an individual's attentional control settings determine whether salient stimuli capture attention. In the current study, we tested a hybrid account called the signal suppression hypothesis, which claims that all stimuli automatically generate a salience signal but that this signal can be actively suppressed by top-down attentional mechanisms. Previous behavioral and electrophysiological research has shown that participants can suppress covert shifts of attention to salient-but-irrelevant color singletons. In this study, we used eye-tracking methods to determine whether participants can also suppress overt shifts of attention to irrelevant singletons. We found that under conditions that promote active suppression of the irrelevant singletons, overt attention was less likely to be directed toward the salient distractors than toward nonsalient distractors. This result provides direct evidence that people can suppress salient-but-irrelevant singletons below baseline levels.

A universal expression/silencing vector in plants.

PubMed

Peretz, Yuval; Mozes-Koch, Rita; Akad, Fuad; Tanne, Edna; Czosnek, Henryk; Sela, Ilan

2007-12-01

A universal vector (IL-60 and auxiliary constructs), expressing or silencing genes in every plant tested to date, is described. Plants that have been successfully manipulated by the IL-60 system include hard-to-manipulate species such as wheat (Triticum duram), pepper (Capsicum annuum), grapevine (Vitis vinifera), citrus, and olive (Olea europaea). Expression or silencing develops within a few days in tomato (Solanum lycopersicum), wheat, and most herbaceous plants and in up to 3 weeks in woody trees. Expression, as tested in tomato, is durable and persists throughout the life span of the plant. The vector is, in fact, a disarmed form of Tomato yellow leaf curl virus, which is applied as a double-stranded DNA and replicates as such. However, the disarmed virus does not support rolling-circle replication, and therefore viral progeny single-stranded DNA is not produced. IL-60 does not integrate into the plant's genome, and the construct, including the expressed gene, is not heritable. IL-60 is not transmitted by the Tomato yellow leaf curl virus's natural insect vector. In addition, artificial satellites were constructed that require a helper virus for replication, movement, and expression. With IL-60 as the disarmed helper "virus," transactivation occurs, resulting in an inducible expressing/silencing system. The system's potential is demonstrated by IL-60-derived suppression of a viral-silencing suppressor of Grapevine virus A, resulting in Grapevine virus A-resistant/tolerant plants.

The dynamic relationship between plant architecture and competition

PubMed Central

Ford, E. David

2014-01-01

In this review, structural and functional changes are described in single-species, even-aged, stands undergoing competition for light. Theories of the competition process as interactions between whole plants have been advanced but have not been successful in explaining these changes and how they vary between species or growing conditions. This task now falls to researchers in plant architecture. Research in plant architecture has defined three important functions of individual plants that determine the process of canopy development and competition: (i) resource acquisition plasticity; (ii) morphogenetic plasticity; (iii) architectural variation in efficiency of interception and utilization of light. In this review, this research is synthesized into a theory for competition based on five groups of postulates about the functioning of plants in stands. Group 1: competition for light takes place at the level of component foliage and branches. Group 2: the outcome of competition is determined by the dynamic interaction between processes that exert dominance and processes that react to suppression. Group 3: species differences may affect both exertion of dominance and reaction to suppression. Group 4: individual plants may simultaneously exhibit, in different component parts, resource acquisition and morphogenetic plasticity. Group 5: mortality is a time-delayed response to suppression. Development of architectural models when combined with field investigations is identifying research needed to develop a theory of architectural influences on the competition process. These include analyses of the integration of foliage and branch components into whole-plant growth and precise definitions of environmental control of morphogenetic plasticity and its interaction with acquisition of carbon for plant growth. PMID:24987396

The dynamic relationship between plant architecture and competition.

PubMed

Ford, E David

2014-01-01

In this review, structural and functional changes are described in single-species, even-aged, stands undergoing competition for light. Theories of the competition process as interactions between whole plants have been advanced but have not been successful in explaining these changes and how they vary between species or growing conditions. This task now falls to researchers in plant architecture. Research in plant architecture has defined three important functions of individual plants that determine the process of canopy development and competition: (i) resource acquisition plasticity; (ii) morphogenetic plasticity; (iii) architectural variation in efficiency of interception and utilization of light. In this review, this research is synthesized into a theory for competition based on five groups of postulates about the functioning of plants in stands. Group 1: competition for light takes place at the level of component foliage and branches. Group 2: the outcome of competition is determined by the dynamic interaction between processes that exert dominance and processes that react to suppression. Group 3: species differences may affect both exertion of dominance and reaction to suppression. Group 4: individual plants may simultaneously exhibit, in different component parts, resource acquisition and morphogenetic plasticity. Group 5: mortality is a time-delayed response to suppression. Development of architectural models when combined with field investigations is identifying research needed to develop a theory of architectural influences on the competition process. These include analyses of the integration of foliage and branch components into whole-plant growth and precise definitions of environmental control of morphogenetic plasticity and its interaction with acquisition of carbon for plant growth.

Radiological Impact Associated to Technologically Enhanced Naturally Occurring Radioactive Materials (TENORM) from Coal-Fired Power Plants Emissions - 13436

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

Dinis, Maria de Lurdes; Fiuza, Antonio; Soeiro de Carvalho, Jose

2013-07-01

Certain materials used and produced in a wide range of non-nuclear industries contain enhanced activity concentrations of natural radionuclides. In particular, electricity production from coal is one of the major sources of increased human exposure to naturally occurring radioactive materials. A methodology was developed to assess the radiological impact due to natural radiation background. The developed research was applied to a specific case study, the Sines coal-fired power plant, located in the southwest coastline of Portugal. Gamma radiation measurements were carried out with two different instruments: a sodium iodide scintillation detector counter (SPP2 NF, Saphymo) and a gamma ray spectrometermore » with energy discrimination (Falcon 5000, Canberra). Two circular survey areas were defined within 20 km of the power plant. Forty relevant measurements points were established within the sampling area: 15 urban and 25 suburban locations. Additionally, ten more measurements points were defined, mostly at the 20-km area. The registered gamma radiation varies from 20 to 98.33 counts per seconds (c.p.s.) corresponding to an external gamma exposure rate variable between 87.70 and 431.19 nGy/h. The highest values were measured at locations near the power plant and those located in an area within the 6 and 20 km from the stacks. In situ gamma radiation measurements with energy discrimination identified natural emitting nuclides as well as their decay products (Pb-212, Pb-2142, Ra-226, Th-232, Ac-228, Th-234, Pa-234, U- 235, etc.). According to the results, an influence from the stacks emissions has been identified both qualitatively and quantitatively. The developed methodology accomplished the lack of data in what concerns to radiation rate in the vicinity of Sines coal-fired power plant and consequently the resulting exposure to the nearby population. (authors)« less

Suppression of External NADPH Dehydrogenase—NDB1 in Arabidopsis thaliana Confers Improved Tolerance to Ammonium Toxicity via Efficient Glutathione/Redox Metabolism

PubMed Central

Podgórska, Anna; Borysiuk, Klaudia; Tarnowska, Agata; Jakubiak, Monika; Burian, Maria; Rasmusson, Allan G.

2018-01-01

Environmental stresses, including ammonium (NH4+) nourishment, can damage key mitochondrial components through the production of surplus reactive oxygen species (ROS) in the mitochondrial electron transport chain. However, alternative electron pathways are significant for efficient reductant dissipation in mitochondria during ammonium nutrition. The aim of this study was to define the role of external NADPH-dehydrogenase (NDB1) during oxidative metabolism of NH4+-fed plants. Most plant species grown with NH4+ as the sole nitrogen source experience a condition known as “ammonium toxicity syndrome”. Surprisingly, transgenic Arabidopsis thaliana plants suppressing NDB1 were more resistant to NH4+ treatment. The NDB1 knock-down line was characterized by milder oxidative stress symptoms in plant tissues when supplied with NH4+. Mitochondrial ROS accumulation, in particular, was attenuated in the NDB1 knock-down plants during NH4+ treatment. Enhanced antioxidant defense, primarily concerning the glutathione pool, may prevent ROS accumulation in NH4+-grown NDB1-suppressing plants. We found that induction of glutathione peroxidase-like enzymes and peroxiredoxins in the NDB1-surpressing line contributed to lower ammonium-toxicity stress. The major conclusion of this study was that NDB1 suppression in plants confers tolerance to changes in redox homeostasis that occur in response to prolonged ammonium nutrition, causing cross tolerance among plants. PMID:29747392