WorldWideScience

Sample records for plant defence responses

  1. Grape marc extract acts as elicitor of plant defence responses.

    Science.gov (United States)

    Goupil, Pascale; Benouaret, Razik; Charrier, Olivia; Ter Halle, Alexandra; Richard, Claire; Eyheraguibel, Boris; Thiery, Denis; Ledoigt, Gérard

    2012-07-01

    Plant protection based on novel alternative strategies is a major concern in agriculture to sustain pest management. The marc extract of red grape cultivars reveals plant defence inducer properties. Treatment with grape marc extract efficiently induced hypersensitive reaction-like lesions with cell death evidenced by Evans Blue staining of tobacco leaves. Examination of the infiltration zone and the surrounding areas under UV light revealed the accumulation of autofluorescent compounds. Both leaf infiltration and a foliar spray of the red grape extract on tobacco leaves induced defence gene expression. The PR1 and PR2 target genes were upregulated locally and systemically in tobacco plants following grape marc extract treatment. The grape extract elicited an array of plant defence responses making this natural compound a potential phytosanitary product with a challenging issue and a rather attractive option for sustainable agriculture and environmentally friendly practices.

  2. Signalling network construction for modelling plant defence response.

    Directory of Open Access Journals (Sweden)

    Dragana Miljkovic

    Full Text Available Plant defence signalling response against various pathogens, including viruses, is a complex phenomenon. In resistant interaction a plant cell perceives the pathogen signal, transduces it within the cell and performs a reprogramming of the cell metabolism leading to the pathogen replication arrest. This work focuses on signalling pathways crucial for the plant defence response, i.e., the salicylic acid, jasmonic acid and ethylene signal transduction pathways, in the Arabidopsis thaliana model plant. The initial signalling network topology was constructed manually by defining the representation formalism, encoding the information from public databases and literature, and composing a pathway diagram. The manually constructed network structure consists of 175 components and 387 reactions. In order to complement the network topology with possibly missing relations, a new approach to automated information extraction from biological literature was developed. This approach, named Bio3graph, allows for automated extraction of biological relations from the literature, resulting in a set of (component1, reaction, component2 triplets and composing a graph structure which can be visualised, compared to the manually constructed topology and examined by the experts. Using a plant defence response vocabulary of components and reaction types, Bio3graph was applied to a set of 9,586 relevant full text articles, resulting in 137 newly detected reactions between the components. Finally, the manually constructed topology and the new reactions were merged to form a network structure consisting of 175 components and 524 reactions. The resulting pathway diagram of plant defence signalling represents a valuable source for further computational modelling and interpretation of omics data. The developed Bio3graph approach, implemented as an executable language processing and graph visualisation workflow, is publically available at http://ropot.ijs.si/bio3graph/and can be

  3. Priming, induction and modulation of plant defence responses by bacterial lipopolysaccharides

    DEFF Research Database (Denmark)

    Newman, Mari-Anne; Dow, J. Maxwell; Molinaro, Antonio

    2007-01-01

    Bacterial lipopolysaccharides (LPSs) have multiple roles in plant-microbe interactions. LPS contributes to the low permeability of the outer membrane, which acts as a barrier to protect bacteria from plant-derived antimicrobial substances. Conversely, perception of LPS by plant cells can lead...... to the triggering of defence responses or to the priming of the plant to respond more rapidly and/or to a greater degree to subsequent pathogen challenge. LPS from symbiotic bacteria can have quite different effects on plants to those of pathogens. Some details are emerging of the structures within LPS...... that are responsible for induction of these different plant responses. The lipid A moiety is not solely responsible for all of the effects of LPS in plants; core oligosaccharide and O-antigen components can elicit specific responses. Here, we review the effects of LPS in induction of defence-related responses...

  4. Understanding plant defence responses against herbivore attacks: an essential first step towards the development of sustainable resistance against pests.

    Science.gov (United States)

    Santamaria, M Estrella; Martínez, Manuel; Cambra, Inés; Grbic, Vojislava; Diaz, Isabel

    2013-08-01

    Plant-herbivore relationships are complex interactions encompassing elaborate networks of molecules, signals and strategies used to overcome defences developed by each other. Herbivores use multiple feeding strategies to obtain nutrients from host plants. In turn, plants respond by triggering defence mechanisms to inhibit, block or modify the metabolism of the pest. As part of these defences, herbivore-challenged plants emit volatiles to attract natural enemies and warn neighbouring plants of the imminent threat. In response, herbivores develop a variety of strategies to suppress plant-induced protection. Our understanding of the plant-herbivore interphase is limited, although recent molecular approaches have revealed the participation of a battery of genes, proteins and volatile metabolites in attack-defence processes. This review describes the intricate and dynamic defence systems governing plant-herbivore interactions by examining the diverse strategies plants employ to deny phytophagous arthropods the ability to breach newly developed mechanisms of plant resistance. A cornerstone of this understanding is the use of transgenic tools to unravel the complex networks that control these interactions.

  5. Hexanoic acid protects tomato plants against Botrytis cinerea by priming defence responses and reducing oxidative stress.

    Science.gov (United States)

    Finiti, Ivan; de la O Leyva, María; Vicedo, Begonya; Gómez-Pastor, Rocío; López-Cruz, Jaime; García-Agustín, Pilar; Real, Maria Dolores; González-Bosch, Carmen

    2014-08-01

    Treatment with the resistance priming inducer hexanoic acid (Hx) protects tomato plants from Botrytis cinerea by activating defence responses. To investigate the molecular mechanisms underlying hexanoic acid-induced resistance (Hx-IR), we compared the expression profiles of three different conditions: Botrytis-infected plants (Inf), Hx-treated plants (Hx) and Hx-treated + infected plants (Hx+Inf). The microarray analysis at 24 h post-inoculation showed that Hx and Hx+Inf plants exhibited the differential expression and priming of many Botrytis-induced genes. Interestingly, we found that the activation by Hx of other genes was not altered by the fungus at this time point. These genes may be considered to be specific targets of the Hx priming effect and may help to elucidate its mechanisms of action. It is noteworthy that, in Hx and Hx+Inf plants, there was up-regulation of proteinase inhibitor genes, DNA-binding factors, enzymes involved in plant hormone signalling and synthesis, and, remarkably, the genes involved in oxidative stress. Given the relevance of the oxidative burst occurring in plant-pathogen interactions, the effect of Hx on this process was studied in depth. We showed by specific staining that reactive oxygen species (ROS) accumulation in Hx+Inf plants was reduced and more restricted around infection sites. In addition, these plants showed higher ratios of reduced to oxidized glutathione and ascorbate, and normal levels of antioxidant activities. The results obtained indicate that Hx protects tomato plants from B. cinerea by regulating and priming Botrytis-specific and non-specific genes, preventing the harmful effects of oxidative stress produced by infection. © 2013 BSPP AND JOHN WILEY & SONS LTD.

  6. Identification of plant defence regulators through transcriptional ...

    Indian Academy of Sciences (India)

    2015-02-04

    Feb 4, 2015 ... defence-related genes also supports constitutive activation of defence in cdd1. We screened T-DNA ..... identified through this work as novel plant defence regu- ... to drought stress than untransformed plants (Lee et al. 2012).

  7. Antagonism between salicylic and abscisic acid reflects early host-pathogen conflict and moulds plant defence responses.

    Science.gov (United States)

    de Torres Zabala, Marta; Bennett, Mark H; Truman, William H; Grant, Murray R

    2009-08-01

    The importance of phytohormone balance is increasingly recognized as central to the outcome of plant-pathogen interactions. Recently it has been demonstrated that abscisic acid signalling pathways are utilized by the bacterial phytopathogen Pseudomonas syringae to promote pathogenesis. In this study, we examined the dynamics, inter-relationship and impact of three key acidic phytohormones, salicylic acid, abscisic acid and jasmonic acid, and the bacterial virulence factor, coronatine, during progression of P. syringae infection of Arabidopsis thaliana. We show that levels of SA and ABA, but not JA, appear to play important early roles in determining the outcome of the infection process. SA is required in order to mount a full innate immune responses, while bacterial effectors act rapidly to activate ABA biosynthesis. ABA suppresses inducible innate immune responses by down-regulating SA biosynthesis and SA-mediated defences. Mutant analyses indicated that endogenous ABA levels represent an important reservoir that is necessary for effector suppression of plant-inducible innate defence responses and SA synthesis prior to subsequent pathogen-induced increases in ABA. Enhanced susceptibility due to loss of SA-mediated basal resistance is epistatically dominant over acquired resistance due to ABA deficiency, although ABA also contributes to symptom development. We conclude that pathogen-modulated ABA signalling rapidly antagonizes SA-mediated defences. We predict that hormonal perturbations, either induced or as a result of environmental stress, have a marked impact on pathological outcomes, and we provide a mechanistic basis for understanding priming events in plant defence.

  8. Long-distance signalling in plant defence.

    Science.gov (United States)

    Heil, Martin; Ton, Jurriaan

    2008-06-01

    Plants use inducible defence mechanisms to fend off harmful organisms. Resistance that is induced in response to local attack is often expressed systemically, that is, in organs that are not yet damaged. In the search for translocated defence signals, biochemical studies follow the physical movement of putative signals, and grafting experiments use mutants that are impaired in the production or perception of these signals. Long-distance signals can directly activate defence or can prime for the stronger and faster induction of defence. Historically, research has focused on the vascular transport of signalling metabolites, but volatiles can play a crucial role as well. We compare the advantages and constraints of vascular and airborne signals for the plant, and discuss how they can act in synergy to achieve optimised resistance in distal plant parts.

  9. Salicylic acid-independent plant defence pathways

    NARCIS (Netherlands)

    Pieterse, C.M.J.; Loon, L.C. van

    1999-01-01

    Salicylic acid is an important signalling molecule involved in both locally and systemically induced disease resistance responses. Recent advances in our understanding of plant defence signalling have revealed that plants employ a network of signal transduction pathways, some of which are

  10. Early season herbivore differentially affects plant defence responses to subsequently colonizing herbivores and their abundance in the field

    NARCIS (Netherlands)

    Poelman, E.H.; Broekgaarden, C.; Loon, van J.J.A.; Dicke, M.

    2008-01-01

    Induction of plant defences by early season herbivores can mediate interspecific herbivore competition. We have investigated plant-mediated competition between three herbivorous insects through studies at different levels of biological integration. We have addressed (i) gene expression; (ii) insect

  11. Comparison of defence responses to Botrytis cinerea infection in tomato plants propagated in vitro and grown in vivo

    Directory of Open Access Journals (Sweden)

    Jacek Patykowski

    2013-12-01

    Full Text Available Defence reactions: O2 - generation, superoxide dismutase, catalase, guaiacol peroxidase and ascorbate peroxidase activities after B. cinerea infection in tomato plants propagated in vitro and grown in vivo have been compared. Infection resulted in rapid O2 - generation. Superoxide dismutase activity increase was slower than O2 - response. In plants propagated in vitro catalase and guaiacol peroxidase activities after infection were induced less strongly than in plants grown in vivo. K2HPO4 pretreatment of plants grown in vitro enhanced significantly the activities of catalase and guaiacol peroxidase after infection. Slight restriction of B. cinerea infection development in in vitro propagated plants pretreated with K2HP04 was observed.

  12. Salicylic acid-independent plant defence pathways

    OpenAIRE

    Pieterse, C.M.J.; Loon, L.C. van

    1999-01-01

    Salicylic acid is an important signalling molecule involved in both locally and systemically induced disease resistance responses. Recent advances in our understanding of plant defence signalling have revealed that plants employ a network of signal transduction pathways, some of which are independent of salicylic acid. Evidence is emerging that jasmonic acid and ethylene play key roles in these salicylic acid-independent pathways. Cross-talk between the salicylic acid-dependent and the salicy...

  13. Phospholipase D and phosphatidic acid in plant defence response: from protein–protein and lipid–protein interactions to hormone signalling

    Science.gov (United States)

    Zhao, Jian

    2015-01-01

    Phospholipase Ds (PLDs) and PLD-derived phosphatidic acids (PAs) play vital roles in plant hormonal and environmental responses and various cellular dynamics. Recent studies have further expanded the functions of PLDs and PAs into plant–microbe interaction. The molecular diversities and redundant functions make PLD–PA an important signalling complex regulating lipid metabolism, cytoskeleton dynamics, vesicle trafficking, and hormonal signalling in plant defence through protein–protein and protein–lipid interactions or hormone signalling. Different PLD–PA signalling complexes and their targets have emerged as fast-growing research topics for understanding their numerous but not yet established roles in modifying pathogen perception, signal transduction, and downstream defence responses. Meanwhile, advanced lipidomics tools have allowed researchers to reveal further the mechanisms of PLD–PA signalling complexes in regulating lipid metabolism and signalling, and their impacts on jasmonic acid/oxylipins, salicylic acid, and other hormone signalling pathways that essentially mediate plant defence responses. This review attempts to summarize the progress made in spatial and temporal PLD/PA signalling as well as PLD/PA-mediated modification of plant defence. It presents an in-depth discussion on the functions and potential mechanisms of PLD–PA complexes in regulating actin filament/microtubule cytoskeleton, vesicle trafficking, and hormonal signalling, and in influencing lipid metabolism-derived metabolites as critical signalling components in plant defence responses. The discussion puts PLD–PA in a broader context in order to guide future research. PMID:25680793

  14. A saponin-detoxifying enzyme mediates suppression of plant defences

    Science.gov (United States)

    Bouarab, K.; Melton, R.; Peart, J.; Baulcombe, D.; Osbourn, A.

    2002-08-01

    Plant disease resistance can be conferred by constitutive features such as structural barriers or preformed antimicrobial secondary metabolites. Additional defence mechanisms are activated in response to pathogen attack and include localized cell death (the hypersensitive response). Pathogens use different strategies to counter constitutive and induced plant defences, including degradation of preformed antimicrobial compounds and the production of molecules that suppress induced plant defences. Here we present evidence for a two-component process in which a fungal pathogen subverts the preformed antimicrobial compounds of its host and uses them to interfere with induced defence responses. Antimicrobial saponins are first hydrolysed by a fungal saponin-detoxifying enzyme. The degradation product of this hydrolysis then suppresses induced defence responses by interfering with fundamental signal transduction processes leading to disease resistance.

  15. The dual nature of trehalose in citrus canker disease: a virulence factor for Xanthomonas citri subsp. citri and a trigger for plant defence responses

    KAUST Repository

    Piazza, A.; Zimaro, T.; Garavaglia, B. S.; Ficarra, F. A.; Thomas, L.; Marondedze, C.; Feil, R.; Lunn, J. E.; Gehring, Christoph A; Ottado, J.; Gottig, N.

    2015-01-01

    and proteomic analyses of infected leaves showed that infection with XccΔotsA triggered only weak defence responses in the plant compared with infection with Xcc, and had less impact on the host plant's metabolism than the wild-type strain. These results

  16. Phospholipase D and phosphatidic acid in plant defence response: from protein-protein and lipid-protein interactions to hormone signalling.

    Science.gov (United States)

    Zhao, Jian

    2015-04-01

    Phospholipase Ds (PLDs) and PLD-derived phosphatidic acids (PAs) play vital roles in plant hormonal and environmental responses and various cellular dynamics. Recent studies have further expanded the functions of PLDs and PAs into plant-microbe interaction. The molecular diversities and redundant functions make PLD-PA an important signalling complex regulating lipid metabolism, cytoskeleton dynamics, vesicle trafficking, and hormonal signalling in plant defence through protein-protein and protein-lipid interactions or hormone signalling. Different PLD-PA signalling complexes and their targets have emerged as fast-growing research topics for understanding their numerous but not yet established roles in modifying pathogen perception, signal transduction, and downstream defence responses. Meanwhile, advanced lipidomics tools have allowed researchers to reveal further the mechanisms of PLD-PA signalling complexes in regulating lipid metabolism and signalling, and their impacts on jasmonic acid/oxylipins, salicylic acid, and other hormone signalling pathways that essentially mediate plant defence responses. This review attempts to summarize the progress made in spatial and temporal PLD/PA signalling as well as PLD/PA-mediated modification of plant defence. It presents an in-depth discussion on the functions and potential mechanisms of PLD-PA complexes in regulating actin filament/microtubule cytoskeleton, vesicle trafficking, and hormonal signalling, and in influencing lipid metabolism-derived metabolites as critical signalling components in plant defence responses. The discussion puts PLD-PA in a broader context in order to guide future research. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  17. Development of a qPCR strategy to select bean genes involved in plant defence response and regulated by the Trichoderma velutinum - Rhizoctonia solani interaction

    Directory of Open Access Journals (Sweden)

    Sara Mayo

    2016-08-01

    Full Text Available Bean production is affected by a wide diversity of fungal pathogens, among them Rhizoctonia solani is one of the most important. A strategy to control bean infectious diseases, mainly those caused by fungi, is based on the use of biocontrol agents that can reduce the negative effects of plant pathogens and also can promote positive responses in the plant. Trichoderma is a fungal genus that is able to induce the expression of genes involved in plant defence response and also to promote plant growth, root development and nutrient uptake. In this article, a strategy that combines in silico analysis and real time PCR to detect additional bean defence-related genes, regulated by the presence of Trichoderma velutinum and/or R. solani has been applied. Based in this strategy, from From the 48 bean genes initially analysed, 14 were selected, and only WRKY33, CH5b and hGS showed an up-regulatory response in the presence of T. velutinum. The other genes were or not affected (OSM34 or down-regulated by the presence of this fungus. R. solani infection resulted in a down-regulation of most of the genes analyzed, except PR1, OSM34 and CNGC2 that were not affected, and the presence of both, T. velutinum and R. solani, up-regulates hGS and down-regulates all the other genes analyzed, except CH5b which was not significantly affected.As conclusion, the strategy described in the present work has been shown to be effective to detect genes involved in plant defence, which respond to the presence of a biocontrol agent or to a pathogen and also to the presence of both. The selected genes show significant homology with previously described plant defence genes and they are expressed in bean leaves of plants treated with T. velutinum and/or infected with R. solani.

  18. Inducible indirect defence of plants : from mechanisms to ecological functions

    NARCIS (Netherlands)

    Dicke, M.; Poecke, van R.M.P.; Boer, de J.G.

    2003-01-01

    Inducible defences allow plants to be phenotypically plastic. Inducible indirect defence of plants by attracting carnivorous enemies of herbivorous arthropods can vary with plant species and genotype, with herbivore species or instar and potentially with other environmental conditions. So far,

  19. The dual nature of trehalose in citrus canker disease: a virulence factor for Xanthomonas citri subsp. citri and a trigger for plant defence responses

    KAUST Repository

    Piazza, A.

    2015-03-14

    Xanthomonas citri subsp. citri (Xcc) is a bacterial pathogen that causes citrus canker in susceptible Citrus spp. The Xcc genome contains genes encoding enzymes from three separate pathways of trehalose biosynthesis. Expression of genes encoding trehalose-6-phosphate synthase (otsA) and trehalose phosphatase (otsB) was highly induced during canker development, suggesting that the two-step pathway of trehalose biosynthesis via trehalose-6-phosphate has a function in pathogenesis. This pathway was eliminated from the bacterium by deletion of the otsA gene. The resulting XccΔotsA mutant produced less trehalose than the wild-type strain, was less resistant to salt and oxidative stresses, and was less able to colonize plant tissues. Gene expression and proteomic analyses of infected leaves showed that infection with XccΔotsA triggered only weak defence responses in the plant compared with infection with Xcc, and had less impact on the host plant\\'s metabolism than the wild-type strain. These results suggested that trehalose of bacterial origin, synthesized via the otsA-otsB pathway, in Xcc, plays a role in modifying the host plant\\'s metabolism to its own advantage but is also perceived by the plant as a sign of pathogen attack. Thus, trehalose biosynthesis has both positive and negative consequences for Xcc. On the one hand, it enables this bacterial pathogen to survive in the inhospitable environment of the leaf surface before infection and exploit the host plant\\'s resources after infection, but on the other hand, it is a tell-tale sign of the pathogen\\'s presence that triggers the plant to defend itself against infection. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  20. Transgenerational effects alter plant defence and resistance in nature.

    Science.gov (United States)

    Colicchio, J

    2017-04-01

    Trichomes, or leaf hairs, are epidermal extensions that take a variety of forms and perform many functions in plants, including herbivore defence. In this study, I document genetically determined variation, within-generation plasticity, and a direct role of trichomes in herbivore defence 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 interannual variation in herbivore density and the high cost of plant defence 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. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

  1. Boosting plant defence by beneficial soil microorganisms

    NARCIS (Netherlands)

    Pozo, Maria J.; Loon, L.C. van; Pieterse, C.M.J.

    2004-01-01

    Plants in their environment face potential deleterious organisms such as fungi, bacteria, viruses, nematodes, etc. Many of them are able to cause plant diseases, responsible of important losses in crop production worldwide. But often the outcome of these interactions is not disease, since plants

  2. Cytokinins as key regulators in plant–microbe–insect interactions: connecting plant growth and defence

    NARCIS (Netherlands)

    Giron, D.; Frago, E.; Glevarec, G.; Pieterse, C.M.J.; Dicke, M.

    2013-01-01

    1. Plant hormones play important roles in regulating plant growth and defence by mediating developmental processes and signalling networks involved in plant responses to a wide range of parasitic and mutualistic biotic interactions. 2. Plants are known to rapidly respond to pathogen and herbivore

  3. Assessment of defence in depth for nuclear power plants

    International Nuclear Information System (INIS)

    2005-01-01

    Defence in depth is a comprehensive approach to safety that has been developed by nuclear power experts to ensure with high confidence that the public and the environment are protected from any hazards posed by the use of nuclear power for the generation of electricity. The concepts of defence in depth and safety culture have served the nuclear power industry well as a basic philosophy for the safe design and operation of nuclear power plants. Properly applied, defence in depth ensures that no single human error or equipment failure at one level of defence, nor even a combination of failures at more than one level of defence, propagates to jeopardize defence in depth at the subsequent level or leads to harm to the public or the environment. The importance of the concept of defence in depth is underlined in IAEA Safety Standards, in particular in the requirements set forth in the Safety Standards: Safety of Nuclear Power Plants: Design (NS-R-1) and Safety Assessment and Verification for Nuclear Power Plants (NS-G-1.2). A specific report, Defence in Depth in Nuclear Safety (INSAG-10), describes the objectives, strategy, implementation and future development in the area of defence in depth in nuclear and radiation safety. In the report Basic Safety Principles for Nuclear Power Plants (INSAG-12), defence in depth is recognized as one of the fundamental safety principles that underlie the safety of nuclear power plants. In consonance with those high level publications, this Safety Report provides more specific technical information on the implementation of this concept in the siting, design, construction and operation of nuclear power plants. It describes a method for comprehensive and balanced review of the provisions required for implementing defence in depth in existing plants. This publication is intended to provide guidance primarily for the self-assessment by plant operators of the comprehensiveness and quality of defence in depth provisions. It can be used

  4. Getting prepared for future attack : induction of plant defences by herbivore egg deposition and consequences for the insect community

    NARCIS (Netherlands)

    Pashalidou, F.G.

    2015-01-01

    Plants have evolved intriguing defences against insect herbivores. Compared to constitutive Plants have evolved intriguing defences against insect herbivores. Compared to constitutive defences that are always present, plants can respond with inducible defences when they are attacked. Insect

  5. How insects overcome two-component plant chemical defence

    DEFF Research Database (Denmark)

    Pentzold, Stefan; Zagrobelny, Mika; Rook, Frederik

    2014-01-01

    Insect herbivory is often restricted by glucosylated plant chemical defence compounds that are activated by plant β-glucosidases to release toxic aglucones upon plant tissue damage. Such two-component plant defences are widespread in the plant kingdom and examples of these classes of compounds...... are alkaloid, benzoxazinoid, cyanogenic and iridoid glucosides as well as glucosinolates and salicinoids. Conversely, many insects have evolved a diversity of counteradaptations to overcome this type of constitutive chemical defence. Here we discuss that such counter-adaptations occur at different time points......, before and during feeding as well as during digestion, and at several levels such as the insects’ feeding behaviour, physiology and metabolism. Insect adaptations frequently circumvent or counteract the activity of the plant β-glucosidases, bioactivating enzymes that are a key element in the plant’s two...

  6. Metabolic Engineering of Chemical Defence Pathways in Plant Disease Control

    DEFF Research Database (Denmark)

    Rook, Frederik

    2016-01-01

    on each topic. The chapter reviews the some of the scientific and technical challenges in metabolic engineering and the new possibilities emerging from recent technological developments. It concludes by discussing the outlook for bioengineered chemical defences as part of crop protection strategies, also...... with antimicrobial properties for use in crop protection. It presents an overview of the metabolic engineering efforts made in the area of plant chemical defence. For in-depth information on the characteristics of a specific class of chemical defence compounds, the reader is referred to the specialized reviews...

  7. Infection biology and defence responses in sorghum against Colletotrichum sublineolum

    DEFF Research Database (Denmark)

    Puttalingaiah, Basavaraju; Shetty, Nandini Prasad; Shetty, H. S.

    2009-01-01

    Aims: To investigate the infection biology of Colletotrichum sublineolum (isolate CP2126) and defence responses in leaves of resistant (SC146), intermediately resistant (SC326) and susceptible (BTx623) sorghum genotypes. Methods and Results: Infection biology and defence responses were studied...

  8. Post-translational modification of host proteins in pathogen-triggered defence signalling in plants

    NARCIS (Netherlands)

    Stulemeijer, I.J.E.; Joosten, M.H.A.J.

    2008-01-01

    Microbial plant pathogens impose a continuous threat to global food production. Similar to animals, an innate immune system allows plants to recognize pathogens and swiftly activate defence. To activate a rapid response, receptor-mediated pathogen perception and subsequent downstream signalling

  9. Can genetically based clines in plant defence explain greater herbivory at higher latitudes?

    Science.gov (United States)

    Anstett, Daniel N; Ahern, Jeffrey R; Glinos, Julia; Nawar, Nabanita; Salminen, Juha-Pekka; Johnson, Marc T J

    2015-12-01

    Greater plant defence is predicted to evolve at lower latitudes in response to increased herbivore pressure. However, recent studies question the generality of this pattern. In this study, we tested for genetically based latitudinal clines in resistance to herbivores and underlying defence traits of Oenothera biennis. We grew plants from 137 populations from across the entire native range of O. biennis. Populations from lower latitudes showed greater resistance to multiple specialist and generalist herbivores. These patterns were associated with an increase in total phenolics at lower latitudes. A significant proportion of the phenolics were driven by the concentrations of two major ellagitannins, which exhibited opposing latitudinal clines. Our analyses suggest that these findings are unlikely to be explained by local adaptation of herbivore populations or genetic variation in phenology. Rather greater herbivory at high latitudes can be explained by latitudinal clines in the evolution of plant defences. © 2015 John Wiley & Sons Ltd/CNRS.

  10. Chemical defence and toxins of plants

    NARCIS (Netherlands)

    Yamane, H.; Konno, K.; Sabelis, M.; Takabayashi, J.; Sassa, T.; Oikawa, H.; Mander, L.; Lui, H.W.

    2010-01-01

    Higher plants protect themselves by producing a variety of secondary metabolites and proteins that are involved in defense against herbivores as well as microbial pathogens. Concerning microbial pathogenesis in plants, in many cases, it is known that phytotoxins that are produced by plant pathogens

  11. Chemical defence and toxins of plants

    OpenAIRE

    Yamane, H.; Konno, K.; Sabelis, M.; Takabayashi, J.; Sassa, T.; Oikawa, H.; Mander, L.; Lui, H.W.

    2010-01-01

    Higher plants protect themselves by producing a variety of secondary metabolites and proteins that are involved in defense against herbivores as well as microbial pathogens. Concerning microbial pathogenesis in plants, in many cases, it is known that phytotoxins that are produced by plant pathogens play an important role in disease development causing chlorosis, necrosis, or wilting. This chapter mainly focuses on the chemical structures, distribution, and biosynthesis of defense-related natu...

  12. Identification of plant defence regulators through transcriptional ...

    Indian Academy of Sciences (India)

    ... of 4- week-old soil grown plants of Col-0 and T-DNA insertion mutant line of At2g19810 (SALK_151571). ... repeated at least twice with similar results (hpi – hours post inoculation). .... work of systemic acquired resistance in plants.

  13. Ecological trade-offs between jasmonic acid-dependent direct and indirect plant defences in tritrophic interactions.

    Science.gov (United States)

    Wei, Jianing; Wang, Lizhong; Zhao, Jiuhai; Li, Chuanyou; Ge, Feng; Kang, Le

    2011-01-01

    Recent studies on plants genetically modified in jasmonic acid (JA) signalling support the hypothesis that the jasmonate family of oxylipins plays an important role in mediating direct and indirect plant defences. However, the interaction of two modes of defence in tritrophic systems is largely unknown. In this study, we examined the preference and performance of a herbivorous leafminer (Liriomyza huidobrensis) and its parasitic wasp (Opius dissitus) on three tomato genotypes: a wild-type (WT) plant, a JA biosynthesis (spr2) mutant, and a JA-overexpression 35S::prosys plant. Their proteinase inhibitor production and volatile emission were used as direct and indirect defence factors to evaluate the responses of leafminers and parasitoids. Here, we show that although spr2 mutant plants are compromised in direct defence against the larval leafminers and in attracting parasitoids, they are less attractive to adult flies compared with WT plants. Moreover, in comparison to other genotypes, the 35S::prosys plant displays greater direct and constitutive indirect defences, but reduced success of parasitism by parasitoids. Taken together, these results suggest that there are distinguished ecological trade-offs between JA-dependent direct and indirect defences in genetically modified plants whose fitness should be assessed in tritrophic systems and under natural conditions. © The Authors (2010). Journal compilation © New Phytologist Trust (2010).

  14. Trichoderma harzianum T-78 supplementation of compost stimulates the antioxidant defence system in melon plants.

    Science.gov (United States)

    Bernal-Vicente, Agustina; Pascual, José A; Tittarelli, Fabio; Hernández, José A; Diaz-Vivancos, Pedro

    2015-08-30

    Compost is emerging as an alternative plant growing medium in efforts to achieve more sustainable agriculture. The addition of specific microorganisms such as Trichoderma harzianum to plant growth substrates increases yields and reduces plant diseases, but the mechanisms of such biostimulants and the biocontrol effects are not yet fully understood. In this work we investigated how the addition of citrus and vineyard composts, either alone or in combination with T. harzianum T-78, affects the antioxidant defence system in melon plants under nursery conditions. Compost application and/or Trichoderma inoculation modulated the antioxidant defence system in melon plants. The combination of citrus compost and Trichoderma showed a biostimulant effect that correlated with an increase in ascorbate recycling enzymes (monodehydroascorbate reductase, dehydroascorbate reductase) and peroxidase. Moreover, the inoculation of both composts with Trichoderma increased the activity of antioxidant enzymes, especially those involved in ascorbate recycling. Based on the long-established relationship between ascorbic acid and plant defence responses as well as plant growth and development, it can be suggested that ascorbate recycling activities play a major role in the protection provided by Trichoderma and its biostimulant effect and that these outcomes are linked to increases in antioxidant enzymes. We can conclude that the combination of citrus compost and T. harzianum T-78 constitutes a viable, environmentally friendly strategy for improving melon plant production. © 2014 Society of Chemical Industry.

  15. Role of stress-related hormones in plant defence during early infection of the cyst nematode Heterodera schachtii in Arabidopsis

    Science.gov (United States)

    Kammerhofer, Nina; Radakovic, Zoran; Regis, Jully M A; Dobrev, Petre; Vankova, Radomira; Grundler, Florian M W; Siddique, Shahid; Hofmann, Julia; Wieczorek, Krzysztof

    2015-01-01

    Heterodera schachtii, a plant-parasitic cyst nematode, invades host roots and induces a specific syncytial feeding structure, from which it withdraws all required nutrients, causing severe yield losses. The system H. schachtii–Arabidopsis is an excellent research model for investigating plant defence mechanisms. Such responses are suppressed in well-established syncytia, whereas they are induced during early parasitism. However, the mechanisms by which the defence responses are modulated and the role of phytohormones are largely unknown. The aim of this study was to elucidate the role of hormone-based defence responses at the onset of nematode infection. First, concentrations of main phytohormones were quantified and the expression of several hormone-related genes was analysed using quantitative real-time (qRT)-PCR or GeneChip. Further, the effects of individual hormones were evaluated via nematode attraction and infection assays using plants with altered endogenous hormone concentrations. Our results suggest a pivotal and positive role for ethylene during nematode attraction, whereas jasmonic acid triggers early defence responses against H. schachtii. Salicylic acid seems to be a negative regulator during later syncytium and female development. We conclude that nematodes are able to impose specific changes in hormone pools, thus modulating hormone-based defence and signal transduction in strict dependence on their parasitism stage. PMID:25825039

  16. Interactive effects of above- and belowground herbivory and plant competition on plant growth and defence

    NARCIS (Netherlands)

    Jing, Y.; Raaijmakers, C.; Kostenko, O.; Kos, M.; Mulder, P.P.J.; Bezemer, T.M.

    2015-01-01

    Competition and herbivory are two major factors that can influence plant growth and plant defence. Although these two factors are often studied separately, they do not operate independently. We examined how aboveground herbivory by beet armyworm larvae (Spodoptera exigua) and belowground herbivory

  17. Plant response to butterfly eggs

    NARCIS (Netherlands)

    Griese, Eddie; Dicke, Marcel; Hilker, Monika; Fatouros, Nina E.

    2017-01-01

    Plants employ various defences killing the insect attacker in an early stage. Oviposition by cabbage white butterflies (Pieris spp.) on brassicaceous plants, including Brassica nigra, induces a hypersensitive response (HR) - like leaf necrosis promoting desiccation of eggs. To gain a deeper insight

  18. Cyclic lipopeptides from Bacillus subtilis activate distinct patterns of defence responses in grapevine.

    Science.gov (United States)

    Farace, Giovanni; Fernandez, Olivier; Jacquens, Lucile; Coutte, François; Krier, François; Jacques, Philippe; Clément, Christophe; Barka, Essaid Ait; Jacquard, Cédric; Dorey, Stéphan

    2015-02-01

    Non-self-recognition of microorganisms partly relies on the perception of microbe-associated molecular patterns (MAMPs) and leads to the activation of an innate immune response. Bacillus subtilis produces three main families of cyclic lipopeptides (LPs), namely surfactins, iturins and fengycins. Although LPs are involved in induced systemic resistance (ISR) activation, little is known about defence responses induced by these molecules and their involvement in local resistance to fungi. Here, we showed that purified surfactin, mycosubtilin (iturin family) and plipastatin (fengycin family) are perceived by grapevine plant cells. Although surfactin and mycosubtilin stimulated grapevine innate immune responses, they differentially activated early signalling pathways and defence gene expression. By contrast, plipastatin perception by grapevine cells only resulted in early signalling activation. Gene expression analysis suggested that mycosubtilin activated salicylic acid (SA) and jasmonic acid (JA) signalling pathways, whereas surfactin mainly induced an SA-regulated response. Although mycosubtilin and plipastatin displayed direct antifungal activity, only surfactin and mycosubtilin treatments resulted in a local long-lasting enhanced tolerance to the necrotrophic fungus Botrytis cinerea in grapevine leaves. Moreover, challenge with specific strains overproducing surfactin and mycosubtilin led to a slightly enhanced stimulation of the defence response compared with the LP-non-producing strain of B. subtilis. Altogether, our results provide the first comprehensive view of the involvement of LPs from B. subtilis in grapevine plant defence and local resistance against the necrotrophic pathogen Bo. cinerea. Moreover, this work is the first to highlight the ability of mycosubtilin to trigger an immune response in plants. © 2014 BSPP AND JOHN WILEY & SONS LTD.

  19. Instar-specific sensitivity of specialist Manduca sexta larvae to induced defences in their host plant Nicotiana attenuata

    NARCIS (Netherlands)

    Van Dam, N.M.; Hermenau, U.; Baldwin, I.T.

    2001-01-01

    1. The time delay associated with the activation of induced defences is thought to be a liability for this type of defence because it allows herbivores to remove biomass before the defence is fully induced. When defences are costly and plants grow with competitors, however, it may be more

  20. Life-history constraints in grassland plant species: a growth-defence trade-off is the norm

    Science.gov (United States)

    E.M. Lind; E.T. Borer; E.W. Seabloom; P.B. Adler; J.D. Bakker; D.M. Blumenthal; M. Crawley; K.F. Davies; J. Firn; D.S. Gruner; S. Harpole; Y. Hautier; H. Hillebrand; J.M.H. Knops; B.A. Melbourne; B. Mortensen; A.C. Risch; M. Schuetz; C.J. Stevens; P.D. Wragg

    2013-01-01

    Plant growth can be limited by resource acquisition and defence against consumers, leading to contrasting trade-off possibilities. The competition-defence hypothesis posits a trade-off between competitive ability and defence against enemies (e.g. herbivores and pathogens). The growth-defence hypothesis suggests that strong competitors for nutrients are also defended...

  1. Strategies to increase Vitamin C in plants: from plant defence perspective to food biofortification

    Directory of Open Access Journals (Sweden)

    Vittoria eLocato

    2013-05-01

    Full Text Available Vitamin C participates in several physiological processes, among others, immune stimulation, synthesis of collagen, hormones, neurotransmitters and iron absorption. Severe deficiency leads to scurvy, whereas a limited vitamin C intake causes general symptoms, such as increased susceptibility to infections, fatigue, insomnia and weight loss. Surprisingly vitamin C deficiencies are spread in both developing and developed countries, with the latter actually trying to overcome this lack through dietary supplements and food fortification. Therefore new strategies aimed to increase vitamin C in food plants would be of interest to improve human health. Interestingly, plants are not only living bioreactors for vitamin C production in optimal growing conditions, but also they can increase their vitamin C content as consequence of stress conditions. An overview of the different approaches aimed at increasing vitamin C level in plant food is given. They include genotype selection by classical breeding, bio-engineering and changes of the agronomic conditions, on the basis of the emerging concepts that plant can enhance vitamin C synthesis as part of defence responses.

  2. Damage-associated responses of the host contribute to defence against cyst nematodes but not root-knot nematodes

    NARCIS (Netherlands)

    Shah, Syed Jehangir; Anjam, Muhammad Shahzad; Mendy, Badou; Anwer, Muhammad Arslan; Habash, Samer S.; Lozano-Torres, Jose L.; Grundler, Florian M.W.; Siddique, Shahid

    2017-01-01

    When nematodes invade and subsequently migrate within plant roots, they generate cell wall fragments (in the form of oligogalacturonides; OGs) that can act as damage-associated molecular patterns and activate host defence responses. However, the molecular mechanisms mediating damage responses in

  3. Mechanisms and ecological consequences of plant defence induction and suppression in herbivore communities.

    Science.gov (United States)

    Kant, M R; Jonckheere, W; Knegt, B; Lemos, F; Liu, J; Schimmel, B C J; Villarroel, C A; Ataide, L M S; Dermauw, W; Glas, J J; Egas, M; Janssen, A; Van Leeuwen, T; Schuurink, R C; Sabelis, M W; Alba, J M

    2015-06-01

    Plants are hotbeds for parasites such as arthropod herbivores, which acquire nutrients and energy from their hosts in order to grow and reproduce. Hence plants are selected to evolve resistance, which in turn selects for herbivores that can cope with this resistance. To preserve their fitness when attacked by herbivores, plants can employ complex strategies that include reallocation of resources and the production of defensive metabolites and structures. Plant defences can be either prefabricated or be produced only upon attack. Those that are ready-made are referred to as constitutive defences. Some constitutive defences are operational at any time while others require activation. Defences produced only when herbivores are present are referred to as induced defences. These can be established via de novo biosynthesis of defensive substances or via modifications of prefabricated substances and consequently these are active only when needed. Inducibility of defence may serve to save energy and to prevent self-intoxication but also implies that there is a delay in these defences becoming operational. Induced defences can be characterized by alterations in plant morphology and molecular chemistry and are associated with a decrease in herbivore performance. These alterations are set in motion by signals generated by herbivores. Finally, a subset of induced metabolites are released into the air as volatiles and function as a beacon for foraging natural enemies searching for prey, and this is referred to as induced indirect defence. The objective of this review is to evaluate (1) which strategies plants have evolved to cope with herbivores and (2) which traits herbivores have evolved that enable them to counter these defences. The primary focus is on the induction and suppression of plant defences and the review outlines how the palette of traits that determine induction/suppression of, and resistance/susceptibility of herbivores to, plant defences can give rise to

  4. Mechanisms and ecological consequences of plant defence induction and suppression in herbivore communities

    Science.gov (United States)

    Kant, M. R.; Jonckheere, W.; Knegt, B.; Lemos, F.; Liu, J.; Schimmel, B. C. J.; Villarroel, C. A.; Ataide, L. M. S.; Dermauw, W.; Glas, J. J.; Egas, M.; Janssen, A.; Van Leeuwen, T.; Schuurink, R. C.; Sabelis, M. W.; Alba, J. M.

    2015-01-01

    Background Plants are hotbeds for parasites such as arthropod herbivores, which acquire nutrients and energy from their hosts in order to grow and reproduce. Hence plants are selected to evolve resistance, which in turn selects for herbivores that can cope with this resistance. To preserve their fitness when attacked by herbivores, plants can employ complex strategies that include reallocation of resources and the production of defensive metabolites and structures. Plant defences can be either prefabricated or be produced only upon attack. Those that are ready-made are referred to as constitutive defences. Some constitutive defences are operational at any time while others require activation. Defences produced only when herbivores are present are referred to as induced defences. These can be established via de novo biosynthesis of defensive substances or via modifications of prefabricated substances and consequently these are active only when needed. Inducibility of defence may serve to save energy and to prevent self-intoxication but also implies that there is a delay in these defences becoming operational. Induced defences can be characterized by alterations in plant morphology and molecular chemistry and are associated with a decrease in herbivore performance. These alterations are set in motion by signals generated by herbivores. Finally, a subset of induced metabolites are released into the air as volatiles and function as a beacon for foraging natural enemies searching for prey, and this is referred to as induced indirect defence. Scope The objective of this review is to evaluate (1) which strategies plants have evolved to cope with herbivores and (2) which traits herbivores have evolved that enable them to counter these defences. The primary focus is on the induction and suppression of plant defences and the review outlines how the palette of traits that determine induction/suppression of, and resistance/susceptibility of herbivores to, plant defences can

  5. The evolution of plant chemical defence - new roles for hydroxynitrile glucosides in Lotus japonicus

    DEFF Research Database (Denmark)

    Knudsen, Camilla

    Plants are sessile organisms well-known to produce a vast array of chemical compounds of which many are used in chemical defence against herbivores and pathogens. The biosynthesis of these plant chemical defence compounds poses a considerable risk of self-toxicity for the plant itself. Several...... on hydroxynitrile glucoside metabolism in the legume model plant Lotus japonicus. Lotus japonicus produces both cyanogenic and non-cyanogenic hydroxynitrile glucosides as chemical defence compounds. The cyanogenic glucosides linamarin and lotaustralin are stored in the cell vacuole as inactive glycosides and, upon...... function and evolution. Further, it contributes to our understanding of the formation and role of biosynthetic gene clusters in plant chemical defence. The bifurcation in hydroxynitrile glucoside biosynthesis and catabolism observed in Lotus japonicus makes it a very suitable model system to study...

  6. Effects of fudioxonil on Botrytis cinerea and on grapevine defence response

    Directory of Open Access Journals (Sweden)

    Anne-Noëlle PETIT

    2011-05-01

    Full Text Available Normal 0 14 false false false IT ZH-TW X-NONE MicrosoftInternetExplorer4 Botrytis bunch rot of grapes is mainly controlled by applying fungicides at three crop stages: the end of flowering (BBCH 68, bunch closure (BBCH 77 and the beginning of veraison (BBCH 81. The phenylpyrroles derivative fudioxonil is among the most effective fungicides registered to control Botrytis cinerea. Its effectiveness was investigated in relation to spray timing, fungicide resistance and defence responses of grapevine. Frequencies of B. cinerea strains which were resistant to fungicides were evaluated at harvest. The frequencies of resistant phenotypes were similar in all treatments except for a class of multidrug resistant strains (MDR 1 whose frequency increased after fudioxonil applications. None of the treatments tested induced defence responses in flowers/berries after fungicide application, suggesting that fudioxonil effectiveness was not related to a stimulation of plant defence processes. The standard program of three fungicide applications provided the best control of B. cinerea  in the Champagne region in comparison with a single treatment of fudioxonil at any of the crop stages tested.

  7. Chemicals on plant surfaces as a heretofore unrecognized, but ecologically informative, class for investigations into plant defence.

    Science.gov (United States)

    LoPresti, Eric F

    2016-11-01

    Plants produce and utilize a great diversity of chemicals for a variety of physiological and ecological purposes. Many of these chemicals defend plants against herbivores, pathogens and competitors. The location of these chemicals varies within the plant, some are located entirely within plant tissues, others exist in the air- (or water-) space around plants, and still others are secreted onto plant surfaces as exudates. I argue herein that the location of a given defensive chemical has profound implications for its ecological function; specifically, I focus on the characteristics of chemical defences secreted onto plant surfaces. Drawing from a broad literature encompassing ecology, evolution, taxonomy and physiology, I found that these external chemical defences (ECDs) are common and widespread in plants and algae; hundreds of examples have been detailed, yet they are not delineated as a separate class from internal chemical defences (ICDs). I propose a novel typology for ECDs and, using existing literature, explore the ecological consequences of the hypothesized unique characteristics of ECDs. The axis of total or proportional investment in ECDs versus ICDs should be considered as one axis of investment by a plant, in the same way as quantitative versus qualitative chemical defences or induced versus constitutive defences is considered. The ease of manipulating ECDs in many plant systems presents a powerful tool to help test plant defence theory (e.g. optimal defence). The framework outlined here integrates various disciplines of botany and ecology and suggests a need for further examinations of exudates in a variety of contexts, as well as recognition of the effects of within-plant localization of defences. © 2015 Cambridge Philosophical Society.

  8. How insects overcome two-component plant chemical defence: plant β-glucosidases as the main target for herbivore adaptation.

    Science.gov (United States)

    Pentzold, Stefan; Zagrobelny, Mika; Rook, Fred; Bak, Søren

    2014-08-01

    Insect herbivory is often restricted by glucosylated plant chemical defence compounds that are activated by plant β-glucosidases to release toxic aglucones upon plant tissue damage. Such two-component plant defences are widespread in the plant kingdom and examples of these classes of compounds are alkaloid, benzoxazinoid, cyanogenic and iridoid glucosides as well as glucosinolates and salicinoids. Conversely, many insects have evolved a diversity of counteradaptations to overcome this type of constitutive chemical defence. Here we discuss that such counter-adaptations occur at different time points, before and during feeding as well as during digestion, and at several levels such as the insects’ feeding behaviour, physiology and metabolism. Insect adaptations frequently circumvent or counteract the activity of the plant β-glucosidases, bioactivating enzymes that are a key element in the plant’s two-component chemical defence. These adaptations include host plant choice, non-disruptive feeding guilds and various physiological adaptations as well as metabolic enzymatic strategies of the insect’s digestive system. Furthermore, insect adaptations often act in combination, may exist in both generalists and specialists, and can act on different classes of defence compounds. We discuss how generalist and specialist insects appear to differ in their ability to use these different types of adaptations: in generalists, adaptations are often inducible, whereas in specialists they are often constitutive. Future studies are suggested to investigate in detail how insect adaptations act in combination to overcome plant chemical defences and to allow ecologically relevant conclusions.

  9. Effects of antimony on redox activities and antioxidant defence systems in sunflower (Helianthus annuus L. plants.

    Directory of Open Access Journals (Sweden)

    Alfonso Ortega

    Full Text Available The alterations induced by the toxicity of antimony (Sb in the roots and leaves of sunflower plants were determined. The plants were grown hydroponically with different concentrations of Sb, a heavy metal which reduces biomass production and growth. There was preferential accumulation of Sb in the tissues of the roots, with the concentrations in the leaves being much lower. The accumulation of other mineral elements was also altered, especially that of Fe and Zn. Chlorophyll content declined, as also did the photosynthetic efficiency, but the carotenoid content remained unaltered. The total content of phenolics, flavonoids, and phenylpropanoid glycosides rose, evidence of their participation in the defence response. Increases were observed in the amount of superoxide anion in both roots and leaves, and in lipid peroxidation levels, especially with the highest Sb concentration of 1.0 mM. The induced oxidative stress leads to a strong increase in the SOD, POX and APX antioxidant activities, while the GR activity was only increased in the leaves and at the 1.0 mM Sb concentration. In contrast, the DHAR activity increased considerably in both organs. The GSNOR activity increased only in roots, and the total RSNOs increased. The total amount of AsA + DHA increased in roots and remained unaltered in leaves, whereas that of GSH + GSSG decreased considerably in all cases. As a whole, these results are evidence for the development of a strong oxidative stress induced by Sb, with there being a clear imbalance in the content of the compounds that constitute the AsA/GSH cycle. 0.5 mM Sb enhances GST expression, especially in leaves. This, together with the increase that was observed in the amount of GSH, may play an important part in detoxification. This oxidative stress affects both the phenolic and the ROS/RNS metabolic processes, which seems to implicate their involvement in the plant's defence and response to the stress.

  10. Fitness consequences of indirect plant defence in the annual weed, Sinapis arvensis

    NARCIS (Netherlands)

    Gols, R.; Wagenaar, R.; Poelman, E.H.; Kruidhof, H.M.; van Loon, J.J.A.; Harvey, J.A.

    2015-01-01

    Plant traits that enhance the attraction of the natural enemies of their herbivores have been postulated to function as an 'indirect defence'. An important underlying assumption is that this enhanced attraction results in increased plant fitness due to reduced herbivory. This assumption has been

  11. A plant EPF-type zinc-finger protein, CaPIF1, involved in defence against pathogens.

    Science.gov (United States)

    Oh, Sang-Keun; Park, Jeong Mee; Joung, Young Hee; Lee, Sanghyeob; Chung, Eunsook; Kim, Soo-Yong; Yu, Seung Hun; Choi, Doil

    2005-05-01

    SUMMARY To understand better the defence responses of plants to pathogen attack, we challenged hot pepper plants with bacterial pathogens and identified transcription factor-encoding genes whose expression patterns were altered during the subsequent hypersensitive response. One of these genes, CaPIF1 (Capsicum annuum Pathogen-Induced Factor 1), was characterized further. This gene encodes a plant-specific EPF-type protein that contains two Cys(2)/His(2) zinc fingers. CaPIF1 expression was rapidly and specifically induced when pepper plants were challenged with bacterial pathogens to which they are resistant. In contrast, challenge with a pathogen to which the plants are susceptible only generated weak CaPIF1 expression. CaPIF1 expression was also strongly induced in pepper leaves by the exogenous application of ethephon, an ethylene-releasing compound, and salicylic acid, whereas methyl jasmonate had only moderate effects. CaPIF1 localized to the nuclei of onion epidermis when expressed as a CaPIF1-smGFP fusion protein. Transgenic tobacco plants over-expressing CaPIF1 driven by the CaMV 35S promoter showed increased resistance to challenge with a tobacco-specific pathogen or non-host bacterial pathogens. These plants also showed constitutive up-regulation of multiple defence-related genes. Moreover, virus-induced silencing of the CaPIF1 orthologue in Nicotiana benthamiana enhanced susceptibility to the same host or non-host bacterial pathogens. These observations provide evidence that an EPF-type Cys(2)/His(2) zinc-finger protein plays a crucial role in the activation of the pathogen defence response in plants.

  12. A defence in depth approach to safety assessment of existing nuclear power plant

    International Nuclear Information System (INIS)

    Butcher, P.; Holloway, N.J.

    1998-01-01

    The safety assessment of plant built to earlier standards requires an approach to prioritisation of upgrades that is based on sound engineering and safety principles. The principles of defence in depth are universally accepted and can form the basis of a prioritisation scheme for safety issues, and hence for the upgrading required to address them. The described scheme includes criteria for acceptability and issue prioritisation that are based on the number of lines of defence and the consequences of their failure. They are thus equivalent in concept to risk criteria, but are based on deterministic principles. This scheme has been applied successfully to the RBMK plant at Ignalina in Lithuania, for which a Western-style Safety Analysis Report has recently been produced and reviewed by joint Western and Eastern teams. An extended Safety Improvement Programme (SIP2) has been developed and agreed, based on prioritisations from the defence in depth assessment. (author)

  13. Plant parasitic nematode effectors target host defence and nuclear functions to establish feeding cells

    Directory of Open Access Journals (Sweden)

    Michaël eQuentin

    2013-03-01

    Full Text Available Plant parasitic nematodes are microscopic worms, the most damaging species of which have adopted a sedentary lifestyle within their hosts. These obligate endoparasites have a biotrophic relationship with plants, in which they induce the differentiation of root cells into hypertrophied, multinucleate feeding cells. Effectors synthesised in the oesophageal glands of the nematode are injected into the plant cells via the syringe-like stylet and play a key role in manipulating the host machinery. The establishment of specialized feeding cells requires these effectors to modulate many aspects of plant cell morphogenesis and physiology, including defence responses. This cell reprogramming requires changes to host nuclear processes. Some proteins encoded by parasitism genes target host nuclei. Several of these proteins were immunolocalised within feeding cell nuclei or shown to interact with host nuclear proteins. Comparative genomics and functional analyses are gradually revealing the roles of nematode effectors. We describe here these effectors and their hypothesised roles in the unique feeding behaviour of these pests.

  14. Defence responses of arabidopsis thaliana to infection by pseudomonas syringae are regulated by the circadian clock

    KAUST Repository

    Bhardwaj, Vaibhav

    2011-10-31

    The circadian clock allows plants to anticipate predictable daily changes in abiotic stimuli, such as light; however, whether the clock similarly allows plants to anticipate interactions with other organisms is unknown. Here we show that Arabidopsis thaliana (Arabidopsis) has circadian clock-mediated variation in resistance to the virulent bacterial pathogen Pseudomonas syringae pv. tomato DC3000 (Pst DC3000), with plants being least susceptible to infection in the subjective morning. We suggest that the increased resistance to Pst DC3000 observed in the morning in Col-0 plants results from clock-mediated modulation of pathogen associated molecular pattern (PAMP)-triggered immunity. Analysis of publicly available microarray data revealed that a large number of Arabidopsis defence-related genes showed both diurnal- and circadian-regulation, including genes involved in the perception of the PAMP flagellin which exhibit a peak in expression in the morning. Accordingly, we observed that PAMP-triggered callose deposition was significantly higher in wild-type plants inoculated with Pst DC3000 hrpA in the subjective morning than in the evening, while no such temporal difference was evident in arrhythmic plants. Our results suggest that PAMP-triggered immune responses are modulated by the circadian clock and that temporal regulation allows plants to anticipate and respond more effectively to pathogen challenges in the daytime. © 2011 Bhardwaj et al.

  15. Soil microbial species loss affects plant biomass and survival of an introduced bacterial strain, but not inducible plant defences.

    Science.gov (United States)

    Kurm, Viola; van der Putten, Wim H; Pineda, Ana; Hol, W H Gera

    2018-02-12

    Plant growth-promoting rhizobacteria (PGPR) strains can influence plant-insect interactions. However, little is known about the effect of changes in the soil bacterial community in general and especially the loss of rare soil microbes on these interactions. Here, the influence of rare soil microbe reduction on induced systemic resistance (ISR) in a wild ecotype of Arabidopsis thaliana against the aphid Myzus persicae was investigated. To create a gradient of microbial abundances, soil was inoculated with a serial dilution of a microbial community and responses of Arabidopsis plants that originated from the same site as the soil microbes were tested. Plant biomass, transcription of genes involved in plant defences, and insect performance were measured. In addition, the effects of the PGPR strain Pseudomonas fluorescens SS101 on plant and insect performance were tested under the influence of the various soil dilution treatments. Plant biomass showed a hump-shaped relationship with soil microbial community dilution, independent of aphid or Pseudomonas treatments. Both aphid infestation and inoculation with Pseudomonas reduced plant biomass, and led to downregulation of PR1 (salicylic acid-responsive gene) and CYP79B3 (involved in synthesis of glucosinolates). Aphid performance and gene transcription were unaffected by soil dilution. Neither the loss of rare microbial species, as caused by soil dilution, nor Pseudomonas affect the resistance of A. thaliana against M. persicae. However, both Pseudomonas survival and plant biomass respond to rare species loss. Thus, loss of rare soil microbial species can have a significant impact on both above- and below-ground organisms. © The Author(s) 2018. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  16. Jasmonate-deficient plants have reduced direct and indirect defences against herbivores

    NARCIS (Netherlands)

    Thaler, J.S.; Farag, M.A.; Paré, P.W.; Dicke, M.

    2002-01-01

    Plants employ a variety of defence mechanisms, some of which act directly by having a negative effect on herbivores and others that act indirectly by attracting natural enemies of herbivores. In this study we asked if a common jasmonate-signalling pathway links the regulation of direct and indirect

  17. The roles of plant phenolics in defence and communication during Agrobacterium and Rhizobium infection.

    Science.gov (United States)

    Bhattacharya, Amita; Sood, Priyanka; Citovsky, Vitaly

    2010-09-01

    Phenolics are aromatic benzene ring compounds with one or more hydroxyl groups produced by plants mainly for protection against stress. The functions of phenolic compounds in plant physiology and interactions with biotic and abiotic environments are difficult to overestimate. Phenolics play important roles in plant development, particularly in lignin and pigment biosynthesis. They also provide structural integrity and scaffolding support to plants. Importantly, phenolic phytoalexins, secreted by wounded or otherwise perturbed plants, repel or kill many microorganisms, and some pathogens can counteract or nullify these defences or even subvert them to their own advantage. In this review, we discuss the roles of phenolics in the interactions of plants with Agrobacterium and Rhizobium.

  18. The multiple strategies of an insect herbivore to overcome plant cyanogenic glucoside defence

    DEFF Research Database (Denmark)

    Pentzold, Stefan; Zagrobelny, Mika; Roelsgaard, Pernille Sølvhøj

    2014-01-01

    Cyanogenic glucosides (CNglcs) are widespread plant defence compounds that release toxic hydrogen cyanide by plant bglucosidase activity after tissue damage. Specialised insect herbivores have evolved counter strategies and some sequester CNglcs, but the underlying mechanisms to keep CNglcs intact...... during feeding and digestion are unknown. We show that CNglc-sequestering Zygaena filipendulae larvae combine behavioural, morphological, physiological and biochemical strategies at different time points during feeding and digestion to avoid toxic hydrolysis of the CNglcs present in their Lotus food...

  19. Buckwheat trypsin inhibitor with helical hairpin structure belongs to a new family of plant defence peptides.

    Science.gov (United States)

    Oparin, Peter B; Mineev, Konstantin S; Dunaevsky, Yakov E; Arseniev, Alexander S; Belozersky, Mikhail A; Grishin, Eugene V; Egorov, Tsezi A; Vassilevski, Alexander A

    2012-08-15

    A new peptide trypsin inhibitor named BWI-2c was obtained from buckwheat (Fagopyrum esculentum) seeds by sequential affinity, ion exchange and reversed-phase chromatography. The peptide was sequenced and found to contain 41 amino acid residues, with four cysteine residues involved in two intramolecular disulfide bonds. Recombinant BWI-2c identical to the natural peptide was produced in Escherichia coli in a form of a cleavable fusion with thioredoxin. The 3D (three-dimensional) structure of the peptide in solution was determined by NMR spectroscopy, revealing two antiparallel α-helices stapled by disulfide bonds. Together with VhTI, a trypsin inhibitor from veronica (Veronica hederifolia), BWI-2c represents a new family of protease inhibitors with an unusual α-helical hairpin fold. The linker sequence between the helices represents the so-called trypsin inhibitory loop responsible for direct binding to the active site of the enzyme that cleaves BWI-2c at the functionally important residue Arg(19). The inhibition constant was determined for BWI-2c against trypsin (1.7×10(-1)0 M), and the peptide was tested on other enzymes, including those from various insect digestive systems, revealing high selectivity to trypsin-like proteases. Structural similarity shared by BWI-2c, VhTI and several other plant defence peptides leads to the acknowledgement of a new widespread family of plant peptides termed α-hairpinins.

  20. Uncovering the defence responses of Eucalyptus to pests and pathogens in the genomics age.

    Science.gov (United States)

    Naidoo, Sanushka; Külheim, Carsten; Zwart, Lizahn; Mangwanda, Ronishree; Oates, Caryn N; Visser, Erik A; Wilken, Febé E; Mamni, Thandekile B; Myburg, Alexander A

    2014-09-01

    Long-lived tree species are subject to attack by various pests and pathogens during their lifetime. This problem is exacerbated by climate change, which may increase the host range for pathogens and extend the period of infestation by pests. Plant defences may involve preformed barriers or induced resistance mechanisms based on recognition of the invader, complex signalling cascades, hormone signalling, activation of transcription factors and production of pathogenesis-related (PR) proteins with direct antimicrobial or anti-insect activity. Trees have evolved some unique defence mechanisms compared with well-studied model plants, which are mostly herbaceous annuals. The genome sequence of Eucalyptus grandis W. Hill ex Maiden has recently become available and provides a resource to extend our understanding of defence in large woody perennials. This review synthesizes existing knowledge of defence mechanisms in model plants and tree species and features mechanisms that may be important for defence in Eucalyptus, such as anatomical variants and the role of chemicals and proteins. Based on the E. grandis genome sequence, we have identified putative PR proteins based on sequence identity to the previously described plant PR proteins. Putative orthologues for PR-1, PR-2, PR-4, PR-5, PR-6, PR-7, PR-8, PR-9, PR-10, PR-12, PR-14, PR-15 and PR-17 have been identified and compared with their orthologues in Populus trichocarpa Torr. & A. Gray ex Hook and Arabidopsis thaliana (L.) Heynh. The survey of PR genes in Eucalyptus provides a first step in identifying defence gene targets that may be employed for protection of the species in future. Genomic resources available for Eucalyptus are discussed and approaches for improving resistance in these hardwood trees, earmarked as a bioenergy source in future, are considered. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Arbuscular Mycorrhizal Fungi and Plant Chemical Defence: Effects of Colonisation on Aboveground and Belowground Metabolomes.

    Science.gov (United States)

    Hill, Elizabeth M; Robinson, Lynne A; Abdul-Sada, Ali; Vanbergen, Adam J; Hodge, Angela; Hartley, Sue E

    2018-02-01

    Arbuscular mycorrhizal fungal (AMF) colonisation of plant roots is one of the most ancient and widespread interactions in ecology, yet the systemic consequences for plant secondary chemistry remain unclear. We performed the first metabolomic investigation into the impact of AMF colonisation by Rhizophagus irregularis on the chemical defences, spanning above- and below-ground tissues, in its host-plant ragwort (Senecio jacobaea). We used a non-targeted metabolomics approach to profile, and where possible identify, compounds induced by AMF colonisation in both roots and shoots. Metabolomics analyses revealed that 33 compounds were significantly increased in the root tissue of AMF colonised plants, including seven blumenols, plant-derived compounds known to be associated with AMF colonisation. One of these was a novel structure conjugated with a malonyl-sugar and uronic acid moiety, hitherto an unreported combination. Such structural modifications of blumenols could be significant for their previously reported functional roles associated with the establishment and maintenance of AM colonisation. Pyrrolizidine alkaloids (PAs), key anti-herbivore defence compounds in ragwort, dominated the metabolomic profiles of root and shoot extracts. Analyses of the metabolomic profiles revealed an increase in four PAs in roots (but not shoots) of AMF colonised plants, with the potential to protect colonised plants from below-ground organisms.

  2. Application of glycerol as a foliar spray activates the defence response and enhances disease resistance of Theobroma cacao.

    Science.gov (United States)

    Zhang, Yufan; Smith, Philip; Maximova, Siela N; Guiltinan, Mark J

    2015-01-01

    Previous work has implicated glycerol-3-phosphate (G3P) as a mobile inducer of systemic immunity in plants. We tested the hypothesis that the exogenous application of glycerol as a foliar spray might enhance the disease resistance of Theobroma cacao through the modulation of endogenous G3P levels. We found that exogenous application of glycerol to cacao leaves over a period of 4 days increased the endogenous level of G3P and decreased the level of oleic acid (18:1). Reactive oxygen species (ROS) were produced (a marker of defence activation) and the expression of many pathogenesis-related genes was induced. Notably, the effects of glycerol application on G3P and 18:1 fatty acid content, and gene expression levels, in cacao leaves were dosage dependent. A 100 mm glycerol spray application was sufficient to stimulate the defence response without causing any observable damage, and resulted in a significantly decreased lesion formation by the cacao pathogen Phytophthora capsici; however, a 500 mm glycerol treatment led to chlorosis and cell death. The effects of glycerol treatment on the level of 18:1 and ROS were constrained to the locally treated leaves without affecting distal tissues. The mechanism of the glycerol-mediated defence response in cacao and its potential use as part of a sustainable farming system are discussed. © 2014 BSPP AND JOHN WILEY & SONS LTD.

  3. An Indirect Defence Trait Mediated through Egg-Induced Maize Volatiles from Neighbouring Plants.

    Directory of Open Access Journals (Sweden)

    Daniel M Mutyambai

    C. sesamiae parasitic wasps indicated that these parasitoids preferred volatiles from oviposited and neighbouring landrace plants compared to those from the control plants. This effect was absent in the standard commercial hybrid we tested. There was no HIPV induction and no difference in parasitoid attraction in neighbouring and control hybrid maize plants. These results show plant-plant signalling: 'Nyamula' maize plants emitting oviposition-induced volatiles attractive to the herbivore's natural enemies can induce this indirect defence trait in conspecific neighbouring undamaged maize plants. Maize plants growing in a field may thus benefit from this indirect defence through airborne signalling which may enhance the fitness of the volatile-emitting plant by increasing predation pressure on herbivores.

  4. The wheat NB-LRR gene TaRCR1 is required for host defence response to the necrotrophic fungal pathogen Rhizoctonia cerealis.

    Science.gov (United States)

    Zhu, Xiuliang; Lu, Chungui; Du, Lipu; Ye, Xingguo; Liu, Xin; Coules, Anne; Zhang, Zengyan

    2017-06-01

    The necrotrophic fungus Rhizoctonia cerealis is the major pathogen causing sharp eyespot disease in wheat (Triticum aestivum). Nucleotide-binding leucine-rich repeat (NB-LRR) proteins often mediate plant disease resistance to biotrophic pathogens. Little is known about the role of NB-LRR genes involved in wheat response to R. cerealis. In this study, a wheat NB-LRR gene, named TaRCR1, was identified in response to R. cerealis infection using Artificial Neural Network analysis based on comparative transcriptomics and its defence role was characterized. The transcriptional level of TaRCR1 was enhanced after R. cerealis inoculation and associated with the resistance level of wheat. TaRCR1 was located on wheat chromosome 3BS and encoded an NB-LRR protein that was consisting of a coiled-coil domain, an NB-ARC domain and 13 imperfect leucine-rich repeats. TaRCR1 was localized in both the cytoplasm and the nucleus. Silencing of TaRCR1 impaired wheat resistance to R. cerealis, whereas TaRCR1 overexpression significantly increased the resistance in transgenic wheat. TaRCR1 regulated certain reactive oxygen species (ROS)-scavenging and production, and defence-related genes, and peroxidase activity. Furthermore, H 2 O 2 pretreatment for 12-h elevated expression levels of TaRCR1 and the above defence-related genes, whereas treatment with a peroxidase inhibitor for 12 h reduced the resistance of TaRCR1-overexpressing transgenic plants and expression levels of these defence-related genes. Taken together, TaRCR1 positively contributes to defence response to R. cerealis through maintaining ROS homoeostasis and regulating the expression of defence-related genes. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  5. Plasma membrane order and fluidity are diversely triggered by elicitors of plant defence.

    Science.gov (United States)

    Sandor, Roman; Der, Christophe; Grosjean, Kevin; Anca, Iulia; Noirot, Elodie; Leborgne-Castel, Nathalie; Lochman, Jan; Simon-Plas, Françoise; Gerbeau-Pissot, Patricia

    2016-09-01

    Although plants are exposed to a great number of pathogens, they usually defend themselves by triggering mechanisms able to limit disease development. Alongside signalling events common to most such incompatible interactions, modifications of plasma membrane (PM) physical properties could be new players in the cell transduction cascade. Different pairs of elicitors (cryptogein, oligogalacturonides, and flagellin) and plant cells (tobacco and Arabidopsis) were used to address the issue of possible modifications of plant PM biophysical properties induced by elicitors and their links to other events of the defence signalling cascade. We observed an increase of PM order whatever the elicitor/plant cell pair used, provided that a signalling cascade was induced. Such membrane modification is dependent on the NADPH oxidase-mediated reactive oxygen species production. Moreover, cryptogein, which is the sole elicitor able to trap sterols, is also the only one able to trigger an increase in PM fluidity. The use of cryptogein variants with altered sterol-binding properties confirms the strong correlation between sterol removal from the PM and PM fluidity enhancement. These results propose PM dynamics as a player in early signalling processes triggered by elicitors of plant defence. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  6. Expression profiling of marker genes responsive to the defence-associated phytohormones salicylic acid, jasmonic acid and ethylene in Brachypodium distachyon.

    Science.gov (United States)

    Kouzai, Yusuke; Kimura, Mamiko; Yamanaka, Yurie; Watanabe, Megumi; Matsui, Hidenori; Yamamoto, Mikihiro; Ichinose, Yuki; Toyoda, Kazuhiro; Onda, Yoshihiko; Mochida, Keiichi; Noutoshi, Yoshiteru

    2016-03-02

    Brachypodium distachyon is a promising model plants for grasses. Infections of Brachypodium by various pathogens that severely impair crop production have been reported, and the species accordingly provides an alternative platform for investigating molecular mechanisms of pathogen virulence and plant disease resistance. To date, we have a broad picture of plant immunity only in Arabidopsis and rice; therefore, Brachypodium may constitute a counterpart that displays the commonality and uniqueness of defence systems among plant species. Phytohormones play key roles in plant biotic stress responses, and hormone-responsive genes are used to qualitatively and quantitatively evaluate disease resistance responses during pathogen infection. For these purposes, defence-related phytohormone marker genes expressed at time points suitable for defence-response monitoring are needed. Information about their expression profiles over time as well as their response specificity is also helpful. However, useful marker genes are still rare in Brachypodium. We selected 34 candidates for Brachypodium marker genes on the basis of protein-sequence similarity to known marker genes used in Arabidopsis and rice. Brachypodium plants were treated with the defence-related phytohormones salicylic acid, jasmonic acid and ethylene, and their transcription levels were measured 24 and 48 h after treatment. Two genes for salicylic acid, 7 for jasmonic acid and 2 for ethylene were significantly induced at either or both time points. We then focused on 11 genes encoding pathogenesis-related (PR) 1 protein and compared their expression patterns with those of Arabidopsis and rice. Phylogenetic analysis suggested that Brachypodium contains several PR1-family genes similar to rice genes. Our expression profiling revealed that regulation patterns of some PR1 genes as well as of markers identified for defence-related phytohormones are closely related to those in rice. We propose that the Brachypodium immune

  7. Inducible defences in Acacia sieberiana in response to giraffe ...

    African Journals Online (AJOL)

    . The resultant browsing pressure has led to the evolution of both physical and chemical responses in Acacia trees. In an observational study, we investigated the physical and chemical defenses in Acacia sieberiana var. woodii in response to ...

  8. Convergent evolution of plant and animal embryo defences by hyperstable non-digestible storage proteins.

    Science.gov (United States)

    Pasquevich, María Yanina; Dreon, Marcos Sebastián; Qiu, Jian-Wen; Mu, Huawei; Heras, Horacio

    2017-11-20

    Plants have evolved sophisticated embryo defences by kinetically-stable non-digestible storage proteins that lower the nutritional value of seeds, a strategy that have not been reported in animals. To further understand antinutritive defences in animals, we analysed PmPV1, massively accumulated in the eggs of the gastropod Pomacea maculata, focusing on how its structure and structural stability features affected its capacity to withstand passage through predator guts. The native protein withstands >50 min boiling and resists the denaturing detergent sodium dodecyl sulphate (SDS), indicating an unusually high structural stability (i.e., kinetic stability). PmPV1 is highly resistant to in vitro proteinase digestion and displays structural stability between pH 2.0-12.0 and 25-85 °C. Furthermore, PmPV1 withstands in vitro and mice digestion and is recovered unchanged in faeces, supporting an antinutritive defensive function. Subunit sequence similarities suggest a common origin and tolerance to mutations. This is the first known animal genus that, like plant seeds, lowers the nutritional value of eggs by kinetically-stable non-digestible storage proteins that survive the gut of predators unaffected. The selective pressure of the harsh gastrointestinal environment would have favoured their appearance, extending by convergent evolution the presence of plant-like hyperstable antinutritive proteins to unattended reproductive stages in animals.

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

    Science.gov (United States)

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

    2015-01-01

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

  10. The Xanthomonas campestris type III effector XopJ targets the host cell proteasome to suppress salicylic-acid mediated plant defence.

    Directory of Open Access Journals (Sweden)

    Suayib Üstün

    Full Text Available The phytopathogenic bacterium Xanthomonas campestris pv. vesicatoria (Xcv requires type III effector proteins (T3Es for virulence. After translocation into the host cell, T3Es are thought to interact with components of host immunity to suppress defence responses. XopJ is a T3E protein from Xcv that interferes with plant immune responses; however, its host cellular target is unknown. Here we show that XopJ interacts with the proteasomal subunit RPT6 in yeast and in planta to inhibit proteasome activity. A C235A mutation within the catalytic triad of XopJ as well as a G2A exchange within the N-terminal myristoylation motif abolishes the ability of XopJ to inhibit the proteasome. Xcv ΔxopJ mutants are impaired in growth and display accelerated symptom development including tissue necrosis on susceptible pepper leaves. Application of the proteasome inhibitor MG132 restored the ability of the Xcv ΔxopJ to attenuate the development of leaf necrosis. The XopJ dependent delay of tissue degeneration correlates with reduced levels of salicylic acid (SA and changes in defence- and senescence-associated gene expression. Necrosis upon infection with Xcv ΔxopJ was greatly reduced in pepper plants with reduced expression of NPR1, a central regulator of SA responses, demonstrating the involvement of SA-signalling in the development of XopJ dependent phenotypes. Our results suggest that XopJ-mediated inhibition of the proteasome interferes with SA-dependent defence response to attenuate onset of necrosis and to alter host transcription. A central role of the proteasome in plant defence is discussed.

  11. Damage-associated responses of the host contribute to defence against cyst nematodes but not root-knot nematodes.

    Science.gov (United States)

    Shah, Syed Jehangir; Anjam, Muhammad Shahzad; Mendy, Badou; Anwer, Muhammad Arslan; Habash, Samer S; Lozano-Torres, Jose L; Grundler, Florian M W; Siddique, Shahid

    2017-12-16

    When nematodes invade and subsequently migrate within plant roots, they generate cell wall fragments (in the form of oligogalacturonides; OGs) that can act as damage-associated molecular patterns and activate host defence responses. However, the molecular mechanisms mediating damage responses in plant-nematode interactions remain unexplored. Here, we characterized the role of a group of cell wall receptor proteins in Arabidopsis, designated as polygalacturonase-inhibiting proteins (PGIPs), during infection with the cyst nematode Heterodera schachtii and the root-knot nematode Meloidogyne incognita. PGIPs are encoded by a family of two genes in Arabidopsis, and are involved in the formation of active OG elicitors. Our results show that PGIP gene expression is strongly induced in response to cyst nematode invasion of roots. Analyses of loss-of-function mutants and overexpression lines revealed that PGIP1 expression attenuates infection of host roots by cyst nematodes, but not root-knot nematodes. The PGIP1-mediated attenuation of cyst nematode infection involves the activation of plant camalexin and indole-glucosinolate pathways. These combined results provide new insights into the molecular mechanisms underlying plant damage perception and response pathways during infection by cyst and root-knot nematodes, and establishes the function of PGIP in plant resistance to cyst nematodes. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  12. Harnessing ant defence at fruits reduces bruchid seed predation in a symbiotic ant–plant mutualism

    Science.gov (United States)

    Pringle, Elizabeth G.

    2014-01-01

    In horizontally transmitted mutualisms, mutualists disperse separately and reassemble in each generation with partners genetically unrelated to those in the previous generation. Because of this, there should be no selection on either partner to enhance the other's reproductive output directly. In symbiotic ant–plant mutualisms, myrmecophytic plants host defensive ant colonies, and ants defend the plants from herbivores. Plants and ants disperse separately, and, although ant defence can indirectly increase plant reproduction by reducing folivory, it is unclear whether ants can also directly increase plant reproduction by defending seeds. The neotropical tree Cordia alliodora hosts colonies of Azteca pittieri ants. The trees produce domatia where ants nest at stem nodes and also at the node between the peduncle and the rachides of the infloresence. Unlike the stem domatia, these reproductive domatia senesce after the tree fruits each year. In this study, I show that the tree's resident ant colony moves into these ephemeral reproductive domatia, where they tend honeydew-producing scale insects and patrol the nearby developing fruits. The presence of ants significantly reduced pre-dispersal seed predation by Amblycerus bruchid beetles, thereby directly increasing plant reproductive output. PMID:24807259

  13. Harnessing ant defence at fruits reduces bruchid seed predation in a symbiotic ant-plant mutualism.

    Science.gov (United States)

    Pringle, Elizabeth G

    2014-06-22

    In horizontally transmitted mutualisms, mutualists disperse separately and reassemble in each generation with partners genetically unrelated to those in the previous generation. Because of this, there should be no selection on either partner to enhance the other's reproductive output directly. In symbiotic ant-plant mutualisms, myrmecophytic plants host defensive ant colonies, and ants defend the plants from herbivores. Plants and ants disperse separately, and, although ant defence can indirectly increase plant reproduction by reducing folivory, it is unclear whether ants can also directly increase plant reproduction by defending seeds. The neotropical tree Cordia alliodora hosts colonies of Azteca pittieri ants. The trees produce domatia where ants nest at stem nodes and also at the node between the peduncle and the rachides of the infloresence. Unlike the stem domatia, these reproductive domatia senesce after the tree fruits each year. In this study, I show that the tree's resident ant colony moves into these ephemeral reproductive domatia, where they tend honeydew-producing scale insects and patrol the nearby developing fruits. The presence of ants significantly reduced pre-dispersal seed predation by Amblycerus bruchid beetles, thereby directly increasing plant reproductive output.

  14. DNA Damage Response and Immune Defence: Links and Mechanisms

    Directory of Open Access Journals (Sweden)

    Björn Schumacher

    2016-08-01

    Full Text Available DNA damage plays a causal role in numerous human pathologies including cancer, premature aging and chronic inflammatory conditions. In response to genotoxic insults, the DNA damage response (DDR orchestrates DNA damage checkpoint activation and facilitates the removal of DNA lesions. The DDR can also arouse the immune system by for example inducing the expression of antimicrobial peptides as well as ligands for receptors found on immune cells. The activation of immune signalling is triggered by different components of the DDR including DNA damage sensors, transducer kinases, and effectors. In this review, we describe recent advances on the understanding of the role of DDR in activating immune signalling. We highlight evidence gained into (i which molecular and cellular pathways of DDR activate immune signalling, (ii how DNA damage drives chronic inflammation, and (iii how chronic inflammation causes DNA damage and pathology in humans.

  15. A novel Meloidogyne graminicola effector, MgMO237, interacts with multiple host defence-related proteins to manipulate plant basal immunity and promote parasitism.

    Science.gov (United States)

    Chen, Jiansong; Hu, Lili; Sun, Longhua; Lin, Borong; Huang, Kun; Zhuo, Kan; Liao, Jinling

    2018-02-27

    Plant-parasitic nematodes can secrete effector proteins into the host tissue to facilitate their parasitism. In this study, we report a novel effector protein, MgMO237, from Meloidogyne graminicola, which is exclusively expressed within the dorsal oesophageal gland cell and markedly up-regulated in parasitic third-/fourth-stage juveniles of M. graminicola. Transient expression of MgMO237 in protoplasts from rice roots showed that MgMO237 was localized in the cytoplasm and nucleus of the host cells. Rice plants overexpressing MgMO237 showed an increased susceptibility to M. graminicola. In contrast, rice plants expressing RNA interference vectors targeting MgMO237 showed an increased resistance to M. graminicola. In addition, yeast two-hybrid and co-immunoprecipitation assays showed that MgMO237 interacted specifically with three rice endogenous proteins, i.e. 1,3-β-glucan synthase component (OsGSC), cysteine-rich repeat secretory protein 55 (OsCRRSP55) and pathogenesis-related BetvI family protein (OsBetvI), which are all related to host defences. Moreover, MgMO237 can suppress host defence responses, including the expression of host defence-related genes, cell wall callose deposition and the burst of reactive oxygen species. These results demonstrate that the effector MgMO237 probably promotes the parasitism of M. graminicola by interacting with multiple host defence-related proteins and suppressing plant basal immunity in the later parasitic stages of nematodes. © 2018 BSPP AND JOHN WILEY & SONS LTD.

  16. Variation in the effectiveness of biotic defence: the case of an opportunistic ant-plant protection mutualism.

    Science.gov (United States)

    Giusto, Bruno; Anstett, Marie-Charlotte; Dounias, Edmond; McKey, Doyle B

    2001-11-01

    Benefits to plants in facultative ant protection mutualisms are highly variable. This allows examination of the sources of this variation and the mechanisms by which ants protect plants. We studied opportunistic interactions between ants and an extrafloral nectary-bearing vine, Dioscorea praehensilis, during 3 different years. Variation in plant protection among years was striking. Several factors affected the effectiveness of the biotic defence. Stems recently emerged from the underground tuber were self-supporting, contacting no other plants and encountering few foraging ants. Stems then became lianescent, and contact with supporting plants greatly increased ant recruitment. Both species and number of ant workers influenced the effect of ants on the major herbivore, the chrysomelid beetle Lilioceris latipennis. Protective actions included limitation of oviposition (reduction in the number of eggs laid on the plant) and predation, leading to increased larval mortality. The probability of successful predation was strongly dependent on larval size. If temporarily low ant-patrolling activity allows larvae to grow beyond a critical size, their mechanical (thick integument) or chemical (plant-derived compounds in a fecal shield) defences become more effective against ants. Secondary metabolites derived from the host plant thus appear to be important for the anti-predator mechanisms of this beetle, being necessary for its survival and reproduction on a host plant that actively recruits ants as a biotic defence against herbivores.

  17. Plant responses to water stress

    Science.gov (United States)

    Kar, Rup Kumar

    2011-01-01

    Terrestrial plants most often encounter drought stress because of erratic rainfall which has become compounded due to present climatic changes.Responses of plants to water stress may be assigned as either injurious change or tolerance index. One of the primary and cardinal changes in response to drought stress is the generation of reactive oxygen species (ROS), which is being considered as the cause of cellular damage. However, recently a signaling role of such ROS in triggering the ROS scavenging system that may confer protection or tolerance against stress is emerging. Such scavenging system consists of antioxidant enzymes like SOD, catalase and peroxidases, and antioxidant compounds like ascorbate, reduced glutathione; a balance between ROS generation and scavenging ultimately determines the oxidative load. As revealed in case of defence against pathogen, signaling via ROS is initiated by NADPH oxidase-catalyzed superoxide generation in the apoplastic space (cell wall) followed by conversion to hydrogen peroxide by the activity of cell wall-localized SOD. Wall peroxidase may also play role in ROS generation for signaling. Hydrogen peroxide may use Ca2+ and MAPK pathway as downstream signaling cascade. Plant hormones associated with stress responses like ABA and ethylene play their role possibly via a cross talk with ROS towards stress tolerance, thus projecting a dual role of ROS under drought stress. PMID:22057331

  18. Evading plant defence: Infestation of poisonous milkweed fruits (Asclepiadaceae) by the fruit fly Dacus siliqualactis (Diptera: Tephritidae).

    Science.gov (United States)

    Schneider, Michael; Wunder, Cora; Reuss, Esther; Toennes, Stefan W; Mebs, Dietrich

    2017-12-01

    To cope with toxic metabolites plants use for defence, herbivorous insects employ various adaptive strategies. For oviposition, the fruit fly Dacus siliqualactis (Tephritidae) uses milkweed plants of the genus Gomphocarpus (Asclepiadaceae) by circumventing the plant's physical (gluey latex) and chemical (toxic cadenolides) defence. With its long, telescope-like ovipositor, the fly penetrates the exo- and endocarp of the fruit and places the eggs on the unripe seeds located in the centre of the fruit. Whereas most plant parts contain high concentrations of cardenolides such as gomphoside, calotropin/calacatin and gomphogenin, only the seeds exhibit low cardenolide levels. By surmounting physical barriers (fruit membranes, latex), the fly secures a safe environment and a latex-free food source of low toxicity for the developing larvae. One amino acid substitution (Q111V) at the cardenolide binding site of the fly's Na + , K + -ATPase was detected, but the significance of that substitution: reducing cardenolide sensitivity or not, is unclear. However, poisoning of the larvae by low levels of cardenolides is assumed to be prevented by non-resorption and excretion of the polar cardenolides, which cannot passively permeate the midgut membrane. This example of an insect-plant interaction demonstrates that by morphological and behavioural adaptation, a fruit fly manages to overcome even highly effective defence mechanisms of its host plant. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. The role of web sharing, species recognition and host-plant defence in interspecific competition between two herbivorous mite species.

    Science.gov (United States)

    Sato, Yukie; Alba, Juan M; Egas, Martijn; Sabelis, Maurice W

    2016-11-01

    When competing with indigenous species, invasive species face a problem, because they typically start with a few colonizers. Evidently, some species succeeded, begging an answer to the question how they invade. Here, we investigate how the invasive spider mite Tetranychus evansi interacts with the indigenous species T. urticae when sharing the solanaceous host plant tomato: do they choose to live together or to avoid each other's colonies? Both species spin protective, silken webs on the leaf surfaces, under which they live in groups of con- and possibly heterospecifics. In Spain, T. evansi invaded the non-crop field where native Tetranychus species including T. urticae dominated. Moreover, T. evansi outcompetes T. urticae when released together on a tomato plant. However, molecular plant studies suggest that T. urticae benefits from the local down-regulation of tomato plant defences by T. evansi, whereas T. evansi suffers from the induction of these defences by T. urticae. Therefore, we hypothesize that T. evansi avoids leaves infested with T. urticae whereas T. urticae prefers leaves infested by T. evansi. Using wild-type tomato and a mutant lacking jasmonate-mediated anti-herbivore defences, we tested the hypothesis and found that T. evansi avoided sharing webs with T. urticae in favour of a web with conspecifics, whereas T. urticae more frequently chose to share webs with T. evansi than with conspecifics. Also, T. evansi shows higher aggregation on a tomato plant than T. urticae, irrespective of whether the mites occur on the plant together or not.

  20. Defence in depth for electric power supplies in Indian nuclear power plants

    International Nuclear Information System (INIS)

    Gupta, S.K.; Srivasista, K.; Solanki, R.B.

    2009-01-01

    The purpose of electric power supply system in a nuclear power plant is to supply and distribute reliable electric power to safety related systems and systems important to safety in various forms, arrangements and combinations of redundancy and diversity in order to perform safety functions required during operational states and design basis events (DBE) such as shutting down the reactor, maintaining the reactor in safe shutdown state, containment isolation and reactor core cooling preventing significant release of radioactive material to the environment. Hence the design basis of electric power supply systems includes identification of DBE that require power supplies, adequacy of redundancy and diversity, environmental conditions to which electric equipment are qualified, identification of loads requiring interrupted and uninterrupted power supplies, time sequence in which emergency loads are to be supplied in case of interruption, provisions for maintaining and testing, consideration for minimum duration capability of emergency power supplies during station blackout etc. Based on operation experience, results of probability safety assessment and certain weaknesses noticed in defence in depth of electric power supply systems, several continuous design improvements have been made in Indian nuclear power plants during operating phase and life extension. Instituting various tests during initial commissioning, subsequent operation and life extension has ensured high standards of performance of electric power supplies. Some of these aspects are highlighted in this paper

  1. Can Plant Defence Mechanisms Provide New Approaches for the Sustainable Control of the Two-Spotted Spider Mite Tetranychus urticae?

    Directory of Open Access Journals (Sweden)

    Blas Agut

    2018-02-01

    Full Text Available Tetranychus urticae (T. urticae Koch is a cosmopolitan, polyphagous mite which causes economic losses in both agricultural and ornamental plants. Some traits of T. urticae hamper its management, including a short life cycle, arrhenotokous parthenogenesis, its haplodiploid sex determination system, and its extraordinary ability to adapt to different hosts and environmental conditions. Currently, the use of chemical and biological control are the major control methods used against this mite. In recent years, some studies have focused on plant defence mechanisms against herbivores. Various families of plant compounds (such as flavonoids, glucosinolates, or acyl sugars have been shown to behave as acaricides. Plants can be induced upon appropriate stimuli to increase their resistance against spider mites. This knowledge, together with the understanding of mechanisms by which T. urticae detoxifies and adapts to pesticides, may complement the control of this pest. Herein, we describe plant volatile compounds (VOCs with repellent activity, and new findings about defence priming against spider mites, which interfere with the T. urticae performance. The use of VOCs and defence priming can be integrated into current management practices and reduce the damage caused by T. urticae in the field by implementing new, more sustainable crop management tools.

  2. Role of stress-related hormones in plant defence during early infection of the cyst nematode Heterodera schachtii in Arabidopsis

    Czech Academy of Sciences Publication Activity Database

    Kammerhofer, N.; Radakovic, Z.; Regis, J.M.A.; Dobrev, Petre; Vaňková, Radomíra; Grundler, F.M.W.; Siddique, S.; Hofmann, J.; Wieczorek, K.

    2015-01-01

    Roč. 207, č. 3 (2015), s. 778-789 ISSN 0028-646X R&D Projects: GA MŠk LD14120 Institutional support: RVO:61389030 Keywords : defence responses * early infection * ethylene Subject RIV: ED - Physiology Impact factor: 7.210, year: 2015

  3. Plant Protein Inhibitors of Enzymes: Their Role in Animal Nutrition and Plant Defence.

    Science.gov (United States)

    Richardson, Michael

    1981-01-01

    Current information and research related to plant protein inhibitors of enzymes are reviewed, including potential uses of the inhibitors for medical treatment and for breeding plant varieties with greater resistance to insects. (DC)

  4. Airborne signals from Trichoderma fungi stimulate iron uptake responses in roots resulting in priming of jasmonic acid-dependent defences in shoots of Arabidopsis thaliana and Solanum lycopersicum.

    Science.gov (United States)

    Martínez-Medina, Ainhoa; Van Wees, Saskia C M; Pieterse, Corné M J

    2017-11-01

    Root colonization by Trichoderma fungi can trigger induced systemic resistance (ISR). In Arabidopsis, Trichoderma-ISR relies on the transcription factor MYB72, which plays a dual role in the onset of ISR and the activation of Fe uptake responses. Volatile compounds (VCs) from rhizobacteria are important elicitors of MYB72 in Arabidopsis roots. Here, we investigated the mode of action of VCs from Trichoderma fungi in the onset of ISR and Fe uptake responses. VCs from Trichoderma asperellum and Trichoderma harzianum were applied in an in vitro split-plate system with Arabidopsis or tomato seedlings. Locally, Trichoderma-VCs triggered MYB72 expression and molecular, physiological and morphological Fe uptake mechanisms in Arabidopsis roots. In leaves, Trichoderma-VCs primed jasmonic acid-dependent defences, leading to an enhanced resistance against Botrytis cinerea. By using Arabidopsis micrografts of VCs-exposed rootstocks and non-exposed scions, we demonstrated that perception of Trichoderma-VCs by the roots leads to a systemic signal that primes shoots for enhanced defences. Trichoderma-VCs also elicited Fe deficiency responses and shoot immunity in tomato, suggesting that this phenomenon is expressed in different plant species. Our results indicate that Trichoderma-VCs trigger locally a readjustment of Fe homeostasis in roots, which links to systemic elicitation of ISR by priming of jasmonic acid-dependent defences. © 2017 John Wiley & Sons Ltd.

  5. Knowing your friends and foes--plant receptor-like kinases as initiators of symbiosis or defence.

    Science.gov (United States)

    Antolín-Llovera, Meritxell; Petutsching, Elena Kristin; Ried, Martina Katharina; Lipka, Volker; Nürnberger, Thorsten; Robatzek, Silke; Parniske, Martin

    2014-12-01

    The decision between defence and symbiosis signalling in plants involves alternative and modular plasma membrane-localized receptor complexes. A critical step in their activation is ligand-induced homo- or hetero-oligomerization of leucine-rich repeat (LRR)- and/or lysin motif (LysM) receptor-like kinases (RLKs). In defence signalling, receptor complexes form upon binding of pathogen-associated molecular patterns (PAMPs), including the bacterial flagellin-derived peptide flg22, or chitin. Similar mechanisms are likely to operate during the perception of microbial symbiont-derived (lipo)-chitooligosaccharides. The structurally related chitin-oligomer ligands chitooctaose and chitotetraose trigger defence and symbiosis signalling, respectively, and their discrimination involves closely related, if not identical, LysM-RLKs. This illustrates the demand for and the challenges imposed on decision mechanisms that ensure appropriate signal initiation. Appropriate signalling critically depends on abundance and localization of RLKs at the cell surface. This is regulated by internalization, which also provides a mechanism for the removal of activated signalling RLKs. Abundance of the malectin-like domain (MLD)-LRR-RLK Symbiosis Receptor-like Kinase (SYMRK) is additionally controlled by cleavage of its modular ectodomain, which generates a truncated and rapidly degraded RLK fragment. This review explores LRR- and LysM-mediated signalling, the involvement of MLD-LRR-RLKs in symbiosis and defence, and the role of endocytosis in RLK function. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  6. The Mediator subunit SFR6/MED16 controls defence gene expression mediated by salicylic acid and jasmonate responsive pathways.

    Science.gov (United States)

    Wathugala, Deepthi L; Hemsley, Piers A; Moffat, Caroline S; Cremelie, Pieter; Knight, Marc R; Knight, Heather

    2012-07-01

    • Arabidopsis SENSITIVE TO FREEZING6 (SFR6) controls cold- and drought-inducible gene expression and freezing- and osmotic-stress tolerance. Its identification as a component of the MEDIATOR transcriptional co-activator complex led us to address its involvement in other transcriptional responses. • Gene expression responses to Pseudomonas syringae, ultraviolet-C (UV-C) irradiation, salicylic acid (SA) and jasmonic acid (JA) were investigated in three sfr6 mutant alleles by quantitative real-time PCR and susceptibility to UV-C irradiation and Pseudomonas infection were assessed. • sfr6 mutants were more susceptible to both Pseudomonas syringae infection and UV-C irradiation. They exhibited correspondingly weaker PR (pathogenesis-related) gene expression than wild-type Arabidopsis following these treatments or after direct application of SA, involved in response to both UV-C and Pseudomonas infection. Other genes, however, were induced normally in the mutants by these treatments. sfr6 mutants were severely defective in expression of plant defensin genes in response to JA; ectopic expression of defensin genes was provoked in wild-type but not sfr6 by overexpression of ERF5. • SFR6/MED16 controls both SA- and JA-mediated defence gene expression and is necessary for tolerance of Pseudomonas syringae infection and UV-C irradiation. It is not, however, a universal regulator of stress gene transcription and is likely to mediate transcriptional activation of specific regulons only. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

  7. Abscisic acid deficiency increases defence responses against Myzus persicae in Arabidopsis.

    Science.gov (United States)

    Hillwig, Melissa S; Chiozza, Mariana; Casteel, Clare L; Lau, Siau Ting; Hohenstein, Jessica; Hernández, Enrique; Jander, Georg; MacIntosh, Gustavo C

    2016-02-01

    Comparison of Arabidopsis thaliana (Arabidopsis) gene expression induced by Myzus persicae (green peach aphid) feeding, aphid saliva infiltration and abscisic acid (ABA) treatment showed a significant positive correlation. In particular, ABA-regulated genes are over-represented among genes that are induced by M. persicae saliva infiltration into Arabidopsis leaves. This suggests that the induction of ABA-related gene expression could be an important component of the Arabidopsis-aphid interaction. Consistent with this hypothesis, M. persicae populations induced ABA production in wild-type plants. Furthermore, aphid populations were smaller on Arabidopsis aba1-1 mutants, which cannot synthesize ABA, and showed a significant preference for wild-type plants compared with the mutant. Total free amino acids, which play an important role in aphid nutrition, were not altered in the aba1-1 mutant line, but the levels of isoleucine (Ile) and tryptophan (Trp) were differentially affected by aphids in wild-type and mutant plants. Recently, indole glucosinolates have been shown to promote aphid resistance in Arabidopsis. In this study, 4-methoxyindol-3-ylmethylglucosinolate was more abundant in the aba1-1 mutant than in wild-type Arabidopsis, suggesting that the induction of ABA signals that decrease the accumulation of defence compounds may be beneficial for aphids. © 2015 BSPP AND JOHN WILEY & SONS LTD.

  8. The combined use of Pochonia chlamydosporia and plant defence activators - a potential sustainable control strategy for Meloidogyne chitwoodi

    Directory of Open Access Journals (Sweden)

    Maria Clara VIEIRA DOS SANTOS

    2014-05-01

    Full Text Available Sustainable strategies are required for control of the root-knot nematode Meloidogyne chitwoodi to reduce dependence on toxic chemical pesticides. The efficacy of the nematophagous fungus Pochonia chlamydosporia in biocontrol could be enhanced by integration with control measures that reduce initial nematode infestations. The use of foliar sprays with plant defence activators can reduce the susceptibility of potato plants to M. chitwoodi. This study assessed effects of combined soil application of P. chlamydosporia with foliar sprays of benzothiadiazole (BTH or cis-jasmone on infection of potatoes by M. chitwoodi. Solanum tuberosum, cv. Désirée plants were grown in soil mixed with 5000 chlamydospores g-1 of soil, sprayed twice with BTH or cis-jasmone and inoculated with 300 M. chitwoodi second-stage juveniles. Forty-five days after inoculation, nematode reproduction, numbers of colony-forming units of the fungus g-1 of soil and g-1 of root, and egg parasitism were assessed by standard techniques. Foliar sprays of BTH or cis-jasmone combined with the fungus reduced nematode reproduction (P<0.05, LSD. The presence of the fungus slightly increased the efficacy of cis-jasmone, as the number of eggs per egg mass was less in plants treated both with cis-jasmone and the fungus than in the plants treated only with the defence activator. The proportion of parasitized eggs was greater in the cis-jasmone treatment where rhizosphere colonisation was less, suggesting that P. chlamydosporia became a poorer rhizosphere coloniser but a more efficient nematode parasite. The addition of P. chlamydosporia to soil in combination with application of inducers of plant defence could be an alternative control strategy to be used against M. chitwoodi in potato.

  9. Partial demethylation of oligogalacturonides by pectin methyl esterase 1 is required for eliciting defence responses in wild strawberry (Fragaria vesca).

    Science.gov (United States)

    Osorio, Sonia; Castillejo, Cristina; Quesada, Miguel A; Medina-Escobar, Nieves; Brownsey, Geoff J; Suau, Rafael; Heredia, Antonio; Botella, Miguel A; Valpuesta, Victoriano

    2008-04-01

    In addition to the role of the cell wall as a physical barrier against pathogens, some of its constituents, such as pectin-derived oligogalacturonides (OGA), are essential components for elicitation of defence responses. To investigate how modifications of pectin alter defence responses, we expressed the fruit-specific Fragaria x ananassa pectin methyl esterase FaPE1 in the wild strawberry Fragaria vesca. Pectin from transgenic ripe fruits differed from the wild-type with regard to the degree and pattern of methyl esterification, as well as the average size of pectin polymers. Purified oligogalacturonides from the transgenic fruits showed a reduced degree of esterification compared to oligogalacturonides from wild-type fruits. This reduced esterification is necessary to elicit defence responses in strawberry. The transgenic F. vesca lines had constitutively activated pathogen defence responses, resulting in higher resistance to the necrotropic fungus Botrytis cinerea. Further studies in F. vesca and Nicotiana benthamiana leaves showed that the elicitation capacity of the oligogalacturonides is more specific than previously envisaged.

  10. Phenylpropanoid Defences in Nicotiana tabacum Cells: Overlapping Metabolomes Indicate Common Aspects to Priming Responses Induced by Lipopolysaccharides, Chitosan and Flagellin-22.

    Directory of Open Access Journals (Sweden)

    Msizi I Mhlongo

    Full Text Available Plants have evolved both constitutive and inducible defence strategies to cope with different biotic stimuli and stresses. Exposure of a plant to a challenging stress can lead to a primed state that allows it to launch a more rapid and stronger defence. Here we applied a metabolomic approach to study and compare the responses induced in Nicotiana tabacum cells by microbe-associated molecular pattern (MAMP molecules, namely lipopolysaccharides (LPS, chitosan (CHT and flagellin-22 (FLG22. Early response metabolites, extracted with methanol, were analysed by UHPLC-MS/MS. Using multivariate statistical tools the metabolic profiles induced by these elicitors were analysed. In the metabolic fingerprint of these agents a total of 19 cinnamic acid derivatives conjugated to quinic acids (chlorogenic acids, shikimic acid, tyramine, polyamines or glucose were found as discriminant biomarkers. In addition, treatment with the phytohormones salicylic acid (SA, methyljasmonic acid (MJ and abscisic acid (ABA resulted in differentially-induced phenylpropanoid pathway metabolites. The results indicate that the phenylpropanoid pathway is activated by these elicitors while hydroxycinnamic acid derivatives are commonly associated with the metabolic response to the MAMPs, and that the activated responses are modulated by both SA and MJ, with ABA not playing a role.

  11. Implementation of Defence in Depth at Nuclear Power Plants. Lessons Learnt from the Fukushima Daiichi Accident

    International Nuclear Information System (INIS)

    Lachaume, Jean-Luc; Miller, Douglass; Rzentkowski, Greg; Lahtinen, Nina; Valtonen, Keijo; Foucher, Laurent; Harikumar, Shri S.; Yamada, Tomoho; Sharafutdinov, Rashet; Kuznetsov, Mark; Carlsson, Lennart; Hanberg, Jan; Theiss, Klaus; Holahan, Gary; Williams, Donna; Nuenighoff, Kay; Wattelle, Emmanuel; Lazo, Edward; White, Andrew; Reig, Javier; Salgado, Nancy; Weightman, Mike

    2016-01-01

    Defence in depth (DiD) is a concept that has been used for many years alongside tools to optimise nuclear safety in reactor design, assessment and regulation. The 2011 Fukushima Daiichi nuclear power plant accident raised many questions and gave unique insight into nuclear safety issues, including DiD. In June 2013, the NEA held a Joint Workshop on Challenges and Enhancements to DiD in Light of the Fukushima Daiichi Accident (NEA, 2014), organised by the NEA Committee on the Safety of Nuclear Installations (CSNI) and the NEA Committee on Nuclear Regulatory Activities (CNRA). It was noted at the time that further work would be beneficial to enhance nuclear safety worldwide, especially with regard to the implementation of DiD. Accordingly, a senior-level task group (STG) was set up to produce a regulatory guidance booklet that would assist member countries in the use of DiD, taking into account lessons learnt from the 2011 accident. This regulatory guidance booklet builds on the work of this NEA workshop, of the International Atomic Energy Agency (IAEA), the Western European Nuclear Regulators Association (WENRA) and of other members of the STG. It uses as its basis the International Nuclear Safety Advisory Group's Defence in Depth in Nuclear Safety study (INSAG-10) (IAEA, 1996). The booklet provides insights into the implementation of DiD by regulators and emergency management authorities after the Fukushima Daiichi accident, aiming to enhance global harmonisation by providing guidance on: - the background to the DiD concept; - the need for independent effectiveness among the safety provisions for the various DiD levels, to the extent practicable; - the need for greater attention to reinforce prevention and mitigation at the various levels; - the vital importance of ensuring that common cause and common mode failures, especially external events acting in combination, do not lead to breaches of safety provisions at several DiD levels, taking note of the

  12. Seismic measures and defence in depth of nuclear power plant. Lessons learned from the great east Japan earthquake

    International Nuclear Information System (INIS)

    Ochiai, Kanehiro

    2011-01-01

    The Great East Japan Earthquake occurred in March 11, 2011 brought about severe accident at nuclear power plant, which gave significant lessons to nuclear experts concerned with safety measures. Concepts of defence in depth was basic philosophy to assure safety of nuclear power plant even against uncertainties exceeding design basis. This concept consisted of prevention, monitoring, and action to mitigate consequences of failures such as a series of physical barriers between the reactor core and the environment, which were called multiple safety systems, each with backup and designed to accommodate human error. As for natural disaster, depth of recognition of characteristic of natural phenomena and its effect and engineering judgment was of prime importance. Different waveforms of ground motion at Fukushima and Onagawa at the Great East Japan Earthquake showed that design ground motion should have large uncertainties. To cope with uncertainties of ground motion, robust seismic measures based on experience were such as design of static seismic intensity and rigid structure of natural period less than 0.1 sec. As for tsunami, defence in depth measures were prepared for the cooling of reactor core, spent fuel and related electric generation equipment with taking into account 1) time lag between tsunami generation and arrival, 2) tsunami affected area could be limited by coastal levee or anti-inundation measure, 3) system redundancy could be assured by different locations of equipments and 4) repair works could be done by shipment of replacement equipment from outside due to limitation of affected regional area. Success examples of Onagawa, Tokai unit 2, Fukushima Daiichi unit 6 and Fukushima Daini Nuclear Power Plants could suggest definite tsunami defence in depth measures. Containment vent system as final heat sink and emergency condenser as reactor core cooling at outage should be properly utilized for Fukushima Daiichi unit 1 Nuclear Power Plant. (T. Tanaka)

  13. ETHYLENE RESPONSE FACTOR 96 positively regulates Arabidopsis resistance to necrotrophic pathogens by direct binding to GCC elements of jasmonate - and ethylene-responsive defence genes.

    Science.gov (United States)

    Catinot, Jérémy; Huang, Jing-Bo; Huang, Pin-Yao; Tseng, Min-Yuan; Chen, Ying-Lan; Gu, Shin-Yuan; Lo, Wan-Sheng; Wang, Long-Chi; Chen, Yet-Ran; Zimmerli, Laurent

    2015-12-01

    The ERF (ethylene responsive factor) family is composed of transcription factors (TFs) that are critical for appropriate Arabidopsis thaliana responses to biotic and abiotic stresses. Here we identified and characterized a member of the ERF TF group IX, namely ERF96, that when overexpressed enhances Arabidopsis resistance to necrotrophic pathogens such as the fungus Botrytis cinerea and the bacterium Pectobacterium carotovorum. ERF96 is jasmonate (JA) and ethylene (ET) responsive and ERF96 transcripts accumulation was abolished in JA-insensitive coi1-16 and in ET-insensitive ein2-1 mutants. Protoplast transactivation and electrophoresis mobility shift analyses revealed that ERF96 is an activator of transcription that binds to GCC elements. In addition, ERF96 mainly localized to the nucleus. Microarray analysis coupled to chromatin immunoprecipitation-PCR of Arabidopsis overexpressing ERF96 revealed that ERF96 enhances the expression of the JA/ET defence genes PDF1.2a, PR-3 and PR-4 as well as the TF ORA59 by direct binding to GCC elements present in their promoters. While ERF96-RNAi plants demonstrated wild-type resistance to necrotrophic pathogens, basal PDF1.2 expression levels were reduced in ERF96-silenced plants. This work revealed ERF96 as a key player of the ERF network that positively regulates the Arabidopsis resistance response to necrotrophic pathogens. © 2015 John Wiley & Sons Ltd.

  14. High CO2 Primes Plant Biotic Stress Defences through Redox-Linked Pathways.

    Science.gov (United States)

    Mhamdi, Amna; Noctor, Graham

    2016-10-01

    Industrial activities have caused tropospheric CO 2 concentrations to increase over the last two centuries, a trend that is predicted to continue for at least the next several decades. Here, we report that growth of plants in a CO 2 -enriched environment activates responses that are central to defense against pathogenic attack. Salicylic acid accumulation was triggered by high-growth CO 2 in Arabidopsis (Arabidopsis thaliana) and other plants such as bean (Phaseolus vulgaris). A detailed analysis in Arabidopsis revealed that elevated CO 2 primes multiple defense pathways, leading to increased resistance to bacterial and fungal challenge. Analysis of gene-specific mutants provided no evidence that activation of plant defense pathways by high CO 2 was caused by stomatal closure. Rather, the activation is partly linked to metabolic effects involving redox signaling. In support of this, genetic modification of redox components (glutathione contents and NADPH-generating enzymes) prevents full priming of the salicylic acid pathway and associated resistance by high CO 2 The data point to a particularly influential role for the nonphosphorylating glyceraldehyde-3-phosphate dehydrogenase, a cytosolic enzyme whose role in plants remains unclear. Our observations add new information on relationships between high CO 2 and oxidative signaling and provide novel insight into plant stress responses in conditions of increased CO 2 . © 2016 American Society of Plant Biologists. All Rights Reserved.

  15. High CO2 Primes Plant Biotic Stress Defences through Redox-Linked Pathways1[OPEN

    Science.gov (United States)

    2016-01-01

    Industrial activities have caused tropospheric CO2 concentrations to increase over the last two centuries, a trend that is predicted to continue for at least the next several decades. Here, we report that growth of plants in a CO2-enriched environment activates responses that are central to defense against pathogenic attack. Salicylic acid accumulation was triggered by high-growth CO2 in Arabidopsis (Arabidopsis thaliana) and other plants such as bean (Phaseolus vulgaris). A detailed analysis in Arabidopsis revealed that elevated CO2 primes multiple defense pathways, leading to increased resistance to bacterial and fungal challenge. Analysis of gene-specific mutants provided no evidence that activation of plant defense pathways by high CO2 was caused by stomatal closure. Rather, the activation is partly linked to metabolic effects involving redox signaling. In support of this, genetic modification of redox components (glutathione contents and NADPH-generating enzymes) prevents full priming of the salicylic acid pathway and associated resistance by high CO2. The data point to a particularly influential role for the nonphosphorylating glyceraldehyde-3-phosphate dehydrogenase, a cytosolic enzyme whose role in plants remains unclear. Our observations add new information on relationships between high CO2 and oxidative signaling and provide novel insight into plant stress responses in conditions of increased CO2. PMID:27578552

  16. The octadecanoid signalling pathway in plants mediates a response to ultraviolet radiation

    International Nuclear Information System (INIS)

    Conconi, A.; Smerdon, M.J.; Howe, G.A.; Ryan, C.A.

    1996-01-01

    Many plant genes that respond to environmental and developmental changes are regulated by jasmonic acid, which is derived from linolenic acid via the octadecanoid pathway. Linolenic acid is an important fatty-acid constituent of membranes in most plant species and its intracellular levels increase in response to certain signals. Here we report that irradiation of tomato leaves with ultraviolet light induces the expression of several plant defensive genes that are normally activated through the octadecanoid pathway after wounding. The response to ultraviolet light is blocked by an inhibitor of the octadecanoid pathway and it does not occur in a tomato mutant defective in this pathway. The ultraviolet irradiation maximally induces the defence genes at levels where cyclobutane pyrimidine dimer formation, an indicator of DNA damage, is less than 0.2 dimers per gene. Our evidence indicates that this plant defence response to certain wavelengths of ultraviolet radiation requires the activation of the octadecanoid defence signalling pathway. (author)

  17. Extraction and quantification of "condensed tannins" as a measure of plant anti-herbivore defence? Revisiting an old problem.

    Science.gov (United States)

    Heil, Martin; Baumann, Birgit; Andary, Claude; Linsenmair, K Eduard; McKey, Doyle

    2002-11-01

    Contents of phenolic compounds in leaf extracts often serve as a measure of plant anti-herbivore defence. This method suffers from the multifunctionality of phenolics and from problems with their colorimetric quantification. Here we present further evidence for the pertinence of these problems. Contents of condensed tannins (CCT) were spectrophotometrically quantified in leaf extracts of 11 closely related mimosoid species, and Spodoptera littoralis caterpillars were reared on artificial diet containing these extracts. The relationship of CCT with caterpillar growth differed considerably among plant species, since both positive and negative correlations were detected. There was, however, a negative correlation of CCT with fungal spore germination, indicating a role of these compounds in resistance to fungi. Detailed knowledge on the structure and biological function of defensive compounds and on the overall composition of leaves is required to estimate a plant's defensive efficacy against a particular group of enemies.

  18. Evidence of viscerally-mediated cold-defence thermoeffector responses in man.

    Science.gov (United States)

    Morris, Nathan B; Filingeri, Davide; Halaki, Mark; Jay, Ollie

    2017-02-15

    Visceral thermoreceptors that modify thermoregulatory responses are widely accepted in animal but not human thermoregulation models. Recently, we have provided evidence of viscerally-mediated sweating alterations in humans during exercise brought about by warm and cool fluid ingestion. In the present study, we characterize the modification of shivering and whole-body thermal sensation during cold stress following the administration of a graded thermal stimuli delivered to the stomach via fluid ingestion at 52, 37, 22 and 7°C. Despite no differences in core and skin temperature, fluid ingestion at 52°C rapidly decreased shivering and sensations of cold compared to 37°C, whereas fluid ingestion at 22 and 7°C led to equivalent increases in these responses. Warm and cold fluid ingestion independently modifies cold defence thermoeffector responses, supporting the presence of visceral thermoreceptors in humans. However, the cold-defence thermoeffector response patterns differed from previously identified hot-defence thermoeffectors. Sudomotor activity is modified by both warm and cold fluid ingestion during heat stress, independently of differences in core and skin temperatures, suggesting independent viscerally-mediated modification of thermoeffectors. The present study aimed to determine whether visceral thermoreceptors modify shivering responses to cold stress. Ten males (mean ± SD: age 27 ± 5 years; height 1.73 ± 0.06 m, weight 78.4 ± 10.7 kg) underwent whole-body cooling via a water perfusion suit at 5°C, on four occasions, to induce a steady-state shivering response, at which point two aliquots of 1.5 ml kg -1 (SML) and 3.0 ml kg -1 (LRG), separated by 20 min, of water at 7, 22, 37 or 52°C were ingested. Rectal, mean skin and mean body temperature (T b ), electromyographic activity (EMG), metabolic rate (M) and whole-body thermal sensation on a visual analogue scale (WBTS) ranging from 0 mm (very cold) to 200 mm (very hot) were all

  19. The Capsicum annuum class IV chitinase ChitIV interacts with receptor-like cytoplasmic protein kinase PIK1 to accelerate PIK1-triggered cell death and defence responses

    Science.gov (United States)

    Kim, Dae Sung; Kim, Nak Hyun; Hwang, Byung Kook

    2015-01-01

    The pepper receptor-like cytoplasmic protein kinase, CaPIK1, which mediates signalling of plant cell death and defence responses was previously identified. Here, the identification of a class IV chitinase, CaChitIV, from pepper plants (Capsicum annuum), which interacts with CaPIK1 and promotes CaPIK1-triggered cell death and defence responses, is reported. CaChitIV contains a signal peptide, chitin-binding domain, and glycol hydrolase domain. CaChitIV expression was up-regulated by Xanthomonas campestris pv. vesicatoria (Xcv) infection. Notably, avirulent Xcv infection rapidly induced CaChitIV expression in pepper leaves. Bimolecular fluorescence complementation and co-immunoprecipitation revealed that CaPIK1 interacts with CaChitIV in planta, and that the CaPIK1–CaChitIV complex is localized mainly in the cytoplasm and plasma membrane. CaChitIV is also localized in the endoplasmic reticulum. Transient co-expression of CaChitIV with CaPIK1 enhanced CaPIK1-triggered cell death response and reactive oxygen species (ROS) and nitric oxide (NO) bursts. Co-silencing of both CaChitIV and CaPIK1 in pepper plants conferred enhanced susceptibility to Xcv infection, which was accompanied by a reduced induction of cell death response, ROS and NO bursts, and defence response genes. Ectopic expression of CaPIK1 in Arabidopsis enhanced basal resistance to Hyaloperonospora arabidopsidis infection. Together, the results suggest that CaChitIV positively regulates CaPIK1-triggered cell death and defence responses through its interaction with CaPIK1. PMID:25694549

  20. Systemic resistance and lipoxygenase-related defence response induced in tomato by Pseudomonas putida strain BTP1

    Directory of Open Access Journals (Sweden)

    Dommes Jacques

    2008-11-01

    Full Text Available Abstract Background Previous studies showed the ability of Pseudomonas putida strain BTP1 to promote induced systemic resistance (ISR in different host plants. Since ISR is long-lasting and not conducive for development of resistance of the targeted pathogen, this phenomenon can take part of disease control strategies. However, in spite of the numerous examples of ISR induced by PGPR in plants, only a few biochemical studies have associated the protective effect with specific host metabolic changes. Results In this study, we showed the protective effect of this bacterium in tomato against Botrytis cinerea. Following treatment by P. putida BTP1, analyses of acid-hydrolyzed leaf extracts showed an accumulation of antifungal material after pathogen infection. The fungitoxic compounds thus mainly accumulate as conjugates from which active aglycones may be liberated through the activity of hydrolytic enzymes. These results suggest that strain BTP1 can elicit systemic phytoalexin accumulation in tomato as one defence mechanism. On another hand, we have shown that key enzymes of the lipoxygenase pathway are stimulated in plants treated with the bacteria as compared with control plants. Interestingly, this stimulation is observed only after pathogen challenge in agreement with the priming concept almost invariably associated with the ISR phenomenon. Conclusion Through the demonstration of phytoalexin accumulation and LOX pathway stimulation in tomato, this work provides new insights into the diversity of defence mechanisms that are inducible by non-pathogenic bacteria in the context of ISR.

  1. Specificity in Mesograzer-Induced Defences in Seagrasses.

    Directory of Open Access Journals (Sweden)

    Begoña Martínez-Crego

    Full Text Available Grazing-induced plant defences that reduce palatability to herbivores are widespread in terrestrial plants and seaweeds, but they have not yet been reported in seagrasses. We investigated the ability of two seagrass species to induce defences in response to direct grazing by three associated mesograzers. Specifically, we conducted feeding-assayed induction experiments to examine how mesograzer-specific grazing impact affects seagrass induction of defences within the context of the optimal defence theory. We found that the amphipod Gammarus insensibilis and the isopod Idotea chelipes exerted a low-intensity grazing on older blades of the seagrass Cymodocea nodosa, which reflects a weak grazing impact that may explain the lack of inducible defences. The isopod Synischia hectica exerted the strongest grazing impact on C. nodosa via high-intensity feeding on young blades with a higher fitness value. This isopod grazing induced defences in C. nodosa as indicated by a consistently lower consumption of blades previously grazed for 5, 12 and 16 days. The lower consumption was maintained when offered tissues with no plant structure (agar-reconstituted food, but showing a reduced size of the previous grazing effect. This indicates that structural traits act in combination with chemical traits to reduce seagrass palatability to the isopod. Increase in total phenolics but not in C:N ratio and total nitrogen of grazed C. nodosa suggests chemical defences rather than a modified nutritional quality as primarily induced chemical traits. We detected no induction of defences in Zostera noltei, which showed the ability to replace moderate losses of young biomass to mesograzers via compensatory growth. Our study provides the first experimental evidence of induction of defences against meso-herbivory that reduce further consumption in seagrasses. It also emphasizes the relevance of grazer identity in determining the level of grazing impact triggering resistance and

  2. Defence responses of arabidopsis thaliana to infection by pseudomonas syringae are regulated by the circadian clock

    KAUST Repository

    Bhardwaj, Vaibhav; Meier, Stuart; Petersen, Lindsay N.; Ingle, Robert A.; Roden, Laura C.

    2011-01-01

    of Arabidopsis defence-related genes showed both diurnal- and circadian-regulation, including genes involved in the perception of the PAMP flagellin which exhibit a peak in expression in the morning. Accordingly, we observed that PAMP-triggered callose deposition

  3. Chemical defences against herbivores

    DEFF Research Database (Denmark)

    Pavia, Henrik; Baumgartner, Finn; Cervin, Gunnar

    2012-01-01

    This chapter focuses on the recent and emerging research involving chemical defences against herbivory in aquatic primary producers. It provides an overview of plant chemical defence theories and highlights recent research on aquatic primary producers addressing a number of aspects...... of these theories, concluding with new chemical approaches to tackle the questions and suggestions for future research directions. It explains that aquatic primary producers are a taxonomically and functionally diverse group of organisms that includes macroalgae, microalgae, and vascular plants. It also states...... that despite the fact that aquatic primary producers constitute a large and diverse group of organisms that vary in their evolutionary histories, selection for chemical defences to resist or reduce grazing are commonplace across the phylogenetic boundaries....

  4. Effect of water deficiency on the cellular status and antioxidant defences in anthyllis sericea. A saharian plant

    International Nuclear Information System (INIS)

    Triki, T.; Selmi, A.

    2017-01-01

    Drought is known as an important restricting factor of plant productivity in arid and semi arid areas of the world. The intended increase of temperature in many areas will intensify this problem. In this study the effect of drought stress was studied in a Saharan plant, Anthyllissericea, by Poly-ethylene glycol (PEG-6000) in three different treatments (-0.2 MPa (control), -1.2 MPa (moderate stress) and -2.1 MPa (severe stress)) after 14 days. Nitric oxide (NO) content, Hydrogen peroxide (H/sub 2/O/sub 2/), RWC, lipid peroxidation and enzymatic antioxidant levels from the leaves were analyzed. Initially, plant growth, RWC and the water potentiel (/psi/ w) were decreased with increase of osmotic stress. Drought induces the increase of NO and hydrogen peroxide levels reaching maximum in severe stress period. MDA, proline content and soluble sugars were found to be higher under moderate and severe stress conditions. Plant employs enzymatic antioxidant system to avoid the subproduction of (ROS) resulting by drought. The analysis of CAT, APX and POD activities showed a significant increase during drought stress. Under moderate and severe stress treatments, the higher activities of H/sub 2/O/sub 2/, NO, CAT and POD showed a stronger system of antioxidant defences in the metabolic regulation during the applied stress. These results propose that A. sericea has the capacity to activate important adaptative mechanisms under dry conditions involving activation of enzymatic antioxidative defense system and higher osmoprotectants accumulation. (author)

  5. Parasitism by Cuscuta pentagona sequentially induces JA and SA defence pathways in tomato

    Science.gov (United States)

    Justin B. Runyon; Mark C. Mescher; Gary W. Felton; Consuelo M. De Moraes

    2010-01-01

    While plant responses to herbivores and pathogens are well characterized, responses to attack by other plants remain largely unexplored. We measured phytohormones and C18 fatty acids in tomato attacked by the parasitic plant Cuscuta pentagona, and used transgenic and mutant plants to explore the roles of the defence-related phytohormones salicylic...

  6. Exogenous ascorbic acid improves defence responses of sunflower (Helianthus annuus) exposed to multiple stresses.

    Science.gov (United States)

    Kaya, Armagan

    2017-09-01

    Ascorbic acid is an important antioxidant that plays role both on growth and development and also stress response of the plant. The purpose of this study was to determine the effect of ascorbate on physiological and biochemical changes of sunflower that was exposed to multiple stresses. Chlorophyll and carotenoid contents decreased and glutathione, ascorbate and malondialdehyde contents as well as antioxidant enzyme activities increased for sunflower plant that was exposed to 50 mM NaCl and pendimethalin at different concentrations. These changes were found to be more significant in groups simultaneously exposed to both stress factors. While malondialdehyde content decreased, chlorophyll, carotenoid, ascorbate, glutathione contents and antioxidant enzyme activities increased in plants treated exogenously with ascorbate, compared to the untreated samples. According to the findings of our study; compared to individual stress, the effect of stress is more pronounced in sunflower exposed to multiple stresses, and treatment with exogenous ascorbate reduces the negative effects of stress.

  7. Foliar treatments with Gaultheria procumbens essential oil induce defence responses and resistance against a fungal pathogen in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Sophie eVergnes

    2014-09-01

    Full Text Available Essential oil from Gaultheria procumbens is mainly composed of methylsalicylate (>96%, a compound which can be metabolized in plant tissues to salicylic acid, a phytohormone inducing plant immunity against microbial pathogens. The potential use of G. procumbens essential oil as a biocontrol agent was evaluated on the model plant Arabidopsis thaliana. Expression of a selection of defence genes was detected 1, 6 and 24 hours after essential oil treatment (0.1 ml/L using a high-throughput qPCR-based microfluidic technology. Control treatments included methyl jasmonate and a commercialized salicylic acid analog, benzo(1,2,3-thiadiazole-7carbothiolic acid (BTH. Strong induction of defence markers known to be regulated by the salicylic acid pathway was observed after the treatment with G. procumbens essential oil. Treatment induced the accumulation of total salicylic acid in the wild -type Arabidopsis line Col-0 and analysis of the Arabidopsis line sid2, mutated in a salicylic acid biosynthetic gene, revealed that approximately 30% of methylsalicylate sprayed on the leaves penetrated inside plant tissues and was demethylated by endogenous esterases. Induction of plant resistance by G. procumbens essential oil was tested following inoculation with a GFP-expressing strain of the Arabidopsis fungal pathogen Colletotrichum higginsianum. Flurorescence measurement of infected tissues revealed that treatments led to a strong reduction (60% of pathogen development and that the efficacy of the G. procumbens essential oil was similar to the commercial product BION®. Together, these results show that the G. procubens essential oil is a natural source of methylsalicylate which can be formulated to develop new biocontrol products.

  8. Three lines of defence model and the role of internal audit activities as the response to the global economic crisis

    Science.gov (United States)

    Dragičević Radičević, T.; Stojanović Trivanović, M.; Stanojević, Lj

    2017-05-01

    The existing framework of corporate governance has shown a number of weaknesses, and the result was a new economic crisis at the global level. The main problems were identified as: increased risk of investors, non-transparency of information, conflict of interest between corporation subjects. European Institute of Internal Auditors in response to the strengthening the trust in information, shareholders activism, better communication, which all will lead to the reduction of risks and restore investors confidence, proposed the Model Three Lines of Defence, where the key role has internal audit.

  9. Defence activation in strawberry and pine- Epigenetic changes in treated plants

    OpenAIRE

    Komajda, Ludwika

    2016-01-01

    Strawberry plants (Fragaria x ananassa) and Scots pine (Pinus sylvestris) represent species, withinagriculture and forestry respectively, that are traditionally protected by utilization of pesticidesincluding neurotoxic insecticides. More environmentally friendly protection strategies are thereforehighly desirable. Treating plants with specific metabolites naturally occurring in their tissues might alterepigenetic mechanisms, which in turn may strengthen plants self-defense against diseases a...

  10. Defence responses regulated by jasmonate and delayed senescence caused by ethylene receptor mutation contribute to the tolerance of petunia to Botrytis cinerea.

    Science.gov (United States)

    Wang, Hong; Liu, Gang; Li, Chunxia; Powell, Ann L T; Reid, Michael S; Zhang, Zhen; Jiang, Cai-Zhong

    2013-06-01

    Ethylene and jasmonate (JA) have powerful effects when plants are challenged by pathogens. The inducible promoter-regulated expression of the Arabidopsis ethylene receptor mutant ethylene-insensitive1-1 (etr1-1) causes ethylene insensitivity in petunia. To investigate the molecular mechanisms involved in transgenic petunia responses to Botrytis cinerea related to the ethylene and JA pathways, etr1-1-expressing petunia plants were inoculated with Botrytis cinerea. The induced expression of etr1-1 by a chemical inducer dexamethasone resulted in retarded senescence and reduced disease symptoms on detached leaves and flowers or intact plants. The extent of decreased disease symptoms correlated positively with etr1-1 expression. The JA pathway, independent of the ethylene pathway, activated petunia ethylene response factor (PhERF) expression and consequent defence-related gene expression. These results demonstrate that ethylene induced by biotic stress influences senescence, and that JA in combination with delayed senescence by etr1-1 expression alters tolerance to pathogens. © 2013 BSPP AND JOHN WILEY & SONS LTD.

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

    OpenAIRE

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

    2015-01-01

    eLife digest Many different animals feed on plants, including almost half of all known insect species. Some herbivores?like caterpillars for example?feed by chewing. Others, such as aphids and planthoppers, use syringe-like mouthparts to pierce plants and then feed on the fluids within. To minimize the damage caused by these herbivores, plants activate specific defenses upon attack, including proteins that can inhibit the insect's digestive enzymes. The inhibitors are effective against chewin...

  12. The intrinsically disordered structural platform of the plant defence hub protein RPM1-interacting protein 4 provides insights into its mode of action in the host-pathogen interface and evolution of the nitrate-induced domain protein family.

    Science.gov (United States)

    Sun, Xiaolin; Greenwood, David R; Templeton, Matthew D; Libich, David S; McGhie, Tony K; Xue, Bin; Yoon, Minsoo; Cui, Wei; Kirk, Christopher A; Jones, William T; Uversky, Vladimir N; Rikkerink, Erik H A

    2014-09-01

    Arabidopsis thaliana (At) RPM1-interacting protein 4 (RIN4), targeted by many defence-suppressing bacterial type III effectors and monitored by several resistance proteins, regulates plant immune responses to pathogen-associated molecular patterns and type III effectors. Little is known about the overall protein structure of AtRIN4, especially in its unbound form, and the relevance of structure to its diverse biological functions. AtRIN4 contains two nitrate-induced (NOI) domains and is a member of the NOI family. Using experimental and bioinformatic approaches, we demonstrate that the unbound AtRIN4 is intrinsically disordered under physiological conditions. The intrinsically disordered polypeptide chain of AtRIN4 is interspersed with molecular recognition features (MoRFs) and anchor-identified long-binding regions, potentially allowing it to undergo disorder-to-order transitions upon binding to partner(s). A poly-l-proline II structure, often responsible for protein recognition, is also identified in AtRIN4. By performing bioinformatics analyses on RIN4 homologues from different plant species and the NOI proteins from Arabidopsis, we infer the conservation of intrinsic disorder, MoRFs and long-binding regions of AtRIN4 in other plant species and the NOI family. Intrinsic disorder and MoRFs could provide RIN4 proteins with the binding promiscuity and plasticity required to act as hubs in a pivotal position within plant defence signalling cascades. © 2014 FEBS.

  13. The suppression of tomato defence response genes upon potato cyst nematode infection indicates a key regulatory role of miRNAs.

    Science.gov (United States)

    Święcicka, Magdalena; Skowron, Waldemar; Cieszyński, Piotr; Dąbrowska-Bronk, Joanna; Matuszkiewicz, Mateusz; Filipecki, Marcin; Koter, Marek Daniel

    2017-04-01

    Potato cyst nematode Globodera rostochiensis is an obligate parasite of solanaceous plants, triggering metabolic and morphological changes in roots which may result in substantial crop yield losses. Previously, we used the cDNA-AFLP to study the transcriptional dynamics in nematode infected tomato roots. Now, we present the rescreening of already published, upregulated transcript-derived fragment dataset using the most current tomato transcriptome sequences. Our reanalysis allowed to add 54 novel genes to 135, already found as upregulated in tomato roots upon G. rostochiensis infection (in total - 189). We also created completely new catalogue of downregulated sequences leading to the discovery of 76 novel genes. Functional classification of candidates showed that the 'wound, stress and defence response' category was enriched in the downregulated genes. We confirmed the transcriptional dynamics of six genes by qRT-PCR. To place our results in a broader context, we compared the tomato data with Arabidopsis thaliana, revealing similar proportions of upregulated and downregulated genes as well as similar enrichment of defence related transcripts in the downregulated group. Since transcript suppression is quite common in plant-nematode interactions, we assessed the possibility of miRNA-mediated inverse correlation on several tomato sequences belonging to NB-LRR and receptor-like kinase families. The qRT-PCR of miRNAs and putative target transcripts showed an opposite expression pattern in 9 cases. These results together with in silico analyses of potential miRNA targeting to the full repertoire of tomato R-genes show that miRNA mediated gene suppression may be a key regulatory mechanism during nematode parasitism. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  14. Plant defences against ants provide a pathway to social parasitism in butterflies

    DEFF Research Database (Denmark)

    Patricelli, Dario; Barbero, Francesca; Occhipinti, Andrea

    2015-01-01

    , which in turn may benefit infested Origanum plants by relieving their roots of further damage. Our results suggest a new pathway, whereby social parasites can detect successive resources by employing plant volatiles to simultaneously select their initial plant food and a suitable sequential host....... the exploitation of sequential hosts by the phytophagous-predaceous butterfly Maculinea arion, whose larvae initially feed on Origanum vulgare flowerheads before switching to parasitize Myrmica ant colonies for their main period of growth. Gravid female butterflies were attracted to Origanum plants that emitted...

  15. Mechanisms and ecological consequences of plant defence induction and suppression in herbivore communities

    NARCIS (Netherlands)

    Kant, M.R.; Jonckheere, W.; Knegt, B.; Lemos, F.; Liu, J.; Schimmel, B.C.J.; Villarroel, C.A.; Ataide, L.M.S.; Dermauw, W.; Glas, J.J.; Egas, M.; Janssen, A.; Van Leeuwen, T.; Schuurink, R.C.; Sabelis, M.W.; Alba, J.M.

    2015-01-01

    BACKGROUND: Plants are hotbeds for parasites such as arthropod herbivores, which acquire nutrients and energy from their hosts in order to grow and reproduce. Hence plants are selected to evolve resistance, which in turn selects for herbivores that can cope with this resistance. To preserve their

  16. Fitness consequences of indirect plant defence in the annual weed, Sinapis arvensis

    NARCIS (Netherlands)

    Gols, Rieta; Wagenaar, Roel; Poelman, Erik H.; Kruidhof, H. Marjolein; van Loon, Joop J.A.; Harvey, Jeffrey A.

    2015-01-01

    * Plant traits that enhance the attraction of the natural enemies of their herbivores have been postulated to function as an ‘indirect defence’. An important underlying assumption is that this enhanced attraction results in increased plant fitness due to reduced herbivory. This assumption has been

  17. Fitness consequences of indirect plant defence in the annual weed, Sinapis arvensis

    NARCIS (Netherlands)

    Gols, R.; Wagenaar, R.; Poelman, E.H.; Kruidhof, M.; Loon, van J.J.A.; Harvey, J.A.

    2015-01-01

    1. Plant traits that enhance the attraction of the natural enemies of their herbivores have been postulated to function as an ‘indirect defence’. An important underlying assumption is that this enhanced attraction results in increased plant fitness due to reduced herbivory. This assumption has been

  18. The role of thionins in rice defence against root pathogens.

    Science.gov (United States)

    Ji, Hongli; Gheysen, Godelieve; Ullah, Chhana; Verbeek, Ruben; Shang, Chenjing; De Vleesschauwer, David; Höfte, Monica; Kyndt, Tina

    2015-10-01

    Thionins are antimicrobial peptides that are involved in plant defence. Here, we present an in-depth analysis of the role of rice thionin genes in defence responses against two root pathogens: the root-knot nematode Meloidogyne graminicola and the oomycete Pythium graminicola. The expression of rice thionin genes was observed to be differentially regulated by defence-related hormones, whereas all analysed genes were consistently down-regulated in M. graminicola-induced galls, at least until 7 days post-inoculation (dpi). Transgenic lines of Oryza sativa cv. Nipponbare overproducing OsTHI7 revealed decreased susceptibility to M. graminicola infection and P. graminicola colonization. Taken together, these results demonstrate the role of rice thionin genes in defence against two of the most damaging root pathogens attacking rice. © 2015 BSPP AND JOHN WILEY & SONS LTD.

  19. Early herbivore alert matters: plant-mediated effects of egg deposition on higher trophic levels benefit plant fitness

    NARCIS (Netherlands)

    Pashalidou, F.G.; Frago, E.; Griese, E.; Poelman, E.H.; Loon, van J.J.A.; Dicke, M.; Fatouros, N.E.

    2015-01-01

    Induction of plant defences, specifically in response to herbivore attack, can save costs that would otherwise be needed to maintain defences even in the absence of herbivores. However, plants may suffer considerable damage during the time required to mount these defences against an attacker. This

  20. Plant defences against ants provide a pathway to social parasitism in butterflies

    Science.gov (United States)

    Patricelli, Dario; Barbero, Francesca; Occhipinti, Andrea; Bertea, Cinzia M.; Bonelli, Simona; Casacci, Luca P.; Zebelo, Simon A.; Crocoll, Christoph; Gershenzon, Jonathan; Maffei, Massimo E.; Thomas, Jeremy A.; Balletto, Emilio

    2015-01-01

    Understanding the chemical cues and gene expressions that mediate herbivore–host-plant and parasite–host interactions can elucidate the ecological costs and benefits accruing to different partners in tight-knit community modules, and may reveal unexpected complexities. We investigated the exploitation of sequential hosts by the phytophagous–predaceous butterfly Maculinea arion, whose larvae initially feed on Origanum vulgare flowerheads before switching to parasitize Myrmica ant colonies for their main period of growth. Gravid female butterflies were attracted to Origanum plants that emitted high levels of the monoterpenoid volatile carvacrol, a condition that occurred when ants disturbed their roots: we also found that Origanum expressed four genes involved in monoterpene formation when ants were present, accompanied by a significant induction of jasmonates. When exposed to carvacrol, Myrmica workers upregulated five genes whose products bind and detoxify this biocide, and their colonies were more tolerant of it than other common ant genera, consistent with an observed ability to occupy the competitor-free spaces surrounding Origanum. A cost is potential colony destruction by Ma. arion, which in turn may benefit infested Origanum plants by relieving their roots of further damage. Our results suggest a new pathway, whereby social parasites can detect successive resources by employing plant volatiles to simultaneously select their initial plant food and a suitable sequential host. PMID:26156773

  1. Polymorphism at selected defence gene analogs (DGAs) of Musa ...

    African Journals Online (AJOL)

    One of the major diseases affecting banana is Sigatoka or leaf spot disease that comprises three species, Mycosphaerella fijiensis, Mycosphaerella musicola and Mycosphaerella eumusae. Plants have a large number of defence related genes which trigger a cascade of defense responses that halt the spread of pathogens.

  2. Soil microbial species loss affects plant biomass and survival of an introduced bacterial strain, but not inducible plant defences

    NARCIS (Netherlands)

    Kurm, Viola; Putten, Van Der Wim H.; Pineda, Ana; Hol, G.W.H.

    2018-01-01

    • Background and Aims: Plant growth-promoting rhizobacteria (PGPR) strains can influence plant-insect interactions. However, little is known about the effect of changes in the soil bacterial community in general and especially the loss of rare soil microbes on these interactions. Here, the influence

  3. Soil microbial species loss affects plant biomass and survival of an introduced bacterial strain, but not inducible plant defences

    NARCIS (Netherlands)

    Kurm, Viola; van der Putten, W.H.; Pineda, A.M.; Hol, W.H.G.

    2018-01-01

    • Background and Aims Plant growth-promoting rhizobacteria (PGPR) strains can influence plant–insect interactions. However, little is known about the effect of changes in the soil bacterial community in general and especially the loss of rare soil microbes on these interactions. Here, the influence

  4. Plant Responses to Nanoparticle Stress

    Directory of Open Access Journals (Sweden)

    Zahed Hossain

    2015-11-01

    Full Text Available With the rapid advancement in nanotechnology, release of nanoscale materials into the environment is inevitable. Such contamination may negatively influence the functioning of the ecosystems. Many manufactured nanoparticles (NPs contain heavy metals, which can cause soil and water contamination. Proteomic techniques have contributed substantially in understanding the molecular mechanisms of plant responses against various stresses by providing a link between gene expression and cell metabolism. As the coding regions of genome are responsible for plant adaptation to adverse conditions, protein signatures provide insights into the phytotoxicity of NPs at proteome level. This review summarizes the recent contributions of plant proteomic research to elaborate the complex molecular pathways of plant response to NPs stress.

  5. Responses of plants to air pollution

    National Research Council Canada - National Science Library

    Mudd, J. Brian; Kozlowski, T. T

    1975-01-01

    .... KOZLOWSKI Pollution, 1975 ELROY L. RICE. Allelopathy, (Eds.). Fire and Ecosystems, 1974 (Eds.). Responses of Plants to Air Responses of Plants to Air PollutionRESPONSES OF PLANTS TO AIR POLLUTION E...

  6. Augmenting Plant Immune Responses and Biological Control by Microbial Determinants

    Directory of Open Access Journals (Sweden)

    Sang Moo Lee

    2015-09-01

    Full Text Available Plant have developed sophisticated defence mechanisms against microbial pathogens. The recent accumulated information allow us to understand the nature of plant immune responses followed by recognition of microbial factors/determinants through cutting-edge genomics and multi-omics techniques. However, the practical approaches to sustain plant health using enhancement of plant immunity is yet to be fully appreciated. Here, we overviewed the general concept and representative examples on the plant immunity. The fungal, bacterial, and viral determinants that was previously reported as the triggers of plant immune responses are introduced and described as the potential protocol of biological control. Specifically, the role of chitin, glucan, lipopolysaccharides/extracellular polysaccharides, microbe/pathogen-associated molecular pattern, antibiotics, mimic-phytohormones, N-acyl homoserine lactone, harpin, vitamins, and volatile organic compounds are considered. We hope that this review stimulates scientific community and farmers to broaden their knowledge on the microbial determinant-based biological control and to apply the technology on the integrated pest management program.

  7. Enterococcus faecalis zinc-responsive proteins mediate bacterial defence against zinc overload, lysozyme and oxidative stress

    NARCIS (Netherlands)

    C. Abrantes, Marta; Kok, Jan; de Fatima Silva Lopes, Maria

    2014-01-01

    Two Enterococcus faecalis genes encoding the P-type ATPase EF1400 and the putative SapB protein EF0759 were previously shown to be strongly upregulated in the presence of high concentrations of zinc. In the present work, we showed that a Zn(2+)-responsive DNA-binding motif (zim) is present in the

  8. The fight-or-flight response is associated with PBMC expression profiles related to immune defence and recovery in swine.

    Directory of Open Access Journals (Sweden)

    Michael Oster

    Full Text Available Defining phenotypes according to molecular features would promote the knowledge of functional traits like behaviour in both human and animal research. Beside physiological states or environmental factors, an innate predisposition of individual coping strategies was discussed, including the proactive and reactive pattern. According to backtest reactivity, animals assigned as high-resisting (proactive and low-resisting (reactive were immune challenged with tetanus toxoid in a time course experiment. Using the Affymetrix platform and qPCR, individual coping characteristics were reflected as gene expression signatures in porcine peripheral blood mononuclear cells (PBMC at naïve state (day 0 and in response to the model antigen (day 14, day 28, and day 140. Further, the blood cell count was analysed at all stages. On the transcriptional level, processes acting on cell communication, vasculogenesis, and blood coagulation were highlighted in high-resisting animals at naïve state (day 0, temporarily blurred due to immune challenge (day 14 but subsequently restored and intensified (day 28. Notably, similar amounts of white and red blood cells, platelets and haematocrit between high-resisting and low-resisting samples suggest coping-specific expression patterns rather than alterations in blood cell distribution. Taken together, the gene expression patterns indicate that proactive pigs might favour molecular pathways enabling an effective strategy for defence and recovery. This corroborates the previously suggested belief, that proactive animals are prone to an increased number of injuries as an evolutionary inherited mechanism. In contrast to previous assumptions, coping-specific immunity in pigs lacks inherited shifts between cellular and humoral immune responses.

  9. A cellular backline: specialization of host membranes for defence.

    Science.gov (United States)

    Faulkner, Christine

    2015-03-01

    In plant-pathogen interactions, the host plasma membrane serves as a defence front for pathogens that invade from the extracellular environment. As such, the lipid bilayer acts as a scaffold that targets and delivers defence responses to the site of attack. During pathogen infection, numerous changes in plasma membrane composition, organization, and structure occur. There is increasing evidence that this facilitates the execution of a variety of responses, highlighting the regulatory role membranes play in cellular responses. Membrane microdomains such as lipid rafts are hypothesized to create signalling platforms for receptor signalling in response to pathogen perception and for callose synthesis. Further, the genesis of pathogen-associated structures such as papillae and the extra-haustorial membrane necessitates polarization of membranes and membrane trafficking pathways. Unlocking the mechanisms by which this occurs will enable greater understanding of how targeted defences, some of which result in resistance, are executed. This review will survey some of the changes that occur in host membranes during pathogen attack and how these are associated with the generation of defence responses. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  10. SMART DEFENCE AND DEFENCE RESOURCES MANAGEMENT

    Directory of Open Access Journals (Sweden)

    Teodor FRUNZETI

    2012-12-01

    Full Text Available Ever since the Chicago Summit in May 2012. the Euro-Atlantic community has been imprinted, from the security and defence perspective. by me launch of a new initiative known as smart defence, a concept referring to the need to improve the way in which defence spending is made at the Alliance's level. Smart defence also has a corollary at EU's level — i.e., pooling and sharing - the two notions referring. Overall, to the same procedure and implying a crucial need for the two organizations to coordinate their efforts in this. This article approaches the conceptual meaning of smart defence, with special emphasis on its management dimension regarding the defence resources. As a consequence, it is approached in connection with Other similar concepts such as pooling and sharing', Planning, Programming, Budgeting, and Evaluation System (PPBES, and the Connected Force Initiative.

  11. Induction of defence mechanisms in grapevine leaves by emodin- and anthraquinone-rich plant extracts and their conferred resistance to downy mildew.

    Science.gov (United States)

    Godard, Sophie; Slacanin, Ivan; Viret, Olivier; Gindro, Katia

    2009-09-01

    The ability of two plant extracts, Rheum palmatum root extract (RPRE) and Frangula alnus bark extract (FABE), to protect Vitis vinifera leaves from Plasmopara viticola infection was evaluated. These natural products are toxic to the pathogen and induce defence reactions in a susceptible cultivar of V. vinifera (V. vinifera cv. Chasselas), including stilbenic phytoalexin accumulation, enhanced peroxidase (EC 1.11.1.7) activity, and a hypersensitive reaction. Inhibition of the first stage of biotrophic hyphal development of P. Viticola by the two plant extracts was observed. HPLC-DAD-MS analysis showed that these two natural extracts contain many phenolic compounds belonging to the anthraquinone family, such as rhein, frangulin A, emodin, aloe-emodin, chrysophanol, and physcion. Emodin alone is able to impair P. viticola development and to stimulate viniferins and the accumulation of pterostilbene.

  12. Plant responses to multiple herbivory

    NARCIS (Netherlands)

    Li, Yehua

    2016-01-01

    This thesis explores whether aphid-infestation interferes with the plant response to chewing herbivores and whether this impacts performance and behaviour of individual chewing insect herbivores and their natural enemies, as well as the entire insect community. I investigated this using three

  13. The coat protein of Alfalfa mosaic virus interacts and interferes with the transcriptional activity of the bHLH transcription factor ILR3 promoting salicylic acid-dependent defence signalling response.

    Science.gov (United States)

    Aparicio, Frederic; Pallás, Vicente

    2017-02-01

    During virus infection, specific viral component-host factor interaction elicits the transcriptional reprogramming of diverse cellular pathways. Alfalfa mosaic virus (AMV) can establish a compatible interaction in tobacco and Arabidopsis hosts. We show that the coat protein (CP) of AMV interacts directly with transcription factor (TF) ILR3 of both species. ILR3 is a basic helix-loop-helix (bHLH) family member of TFs, previously proposed to participate in diverse metabolic pathways. ILR3 has been shown to regulate NEET in Arabidopsis, a critical protein in plant development, senescence, iron metabolism and reactive oxygen species (ROS) homeostasis. We show that the AMV CP-ILR3 interaction causes a fraction of this TF to relocate from the nucleus to the nucleolus. ROS, pathogenesis-related protein 1 (PR1) mRNAs, salicylic acid (SA) and jasmonic acid (JA) contents are increased in healthy Arabidopsis loss-of-function ILR3 mutant (ilr3.2) plants, which implicates ILR3 in the regulation of plant defence responses. In AMV-infected wild-type (wt) plants, NEET expression is reduced slightly, but is induced significantly in ilr3.2 mutant plants. Furthermore, the accumulation of SA and JA is induced in Arabidopsis wt-infected plants. AMV infection in ilr3.2 plants increases JA by over 10-fold, and SA is reduced significantly, indicating an antagonist crosstalk effect. The accumulation levels of viral RNAs are decreased significantly in ilr3.2 mutants, but the virus can still systemically invade the plant. The AMV CP-ILR3 interaction may down-regulate a host factor, NEET, leading to the activation of plant hormone responses to obtain a hormonal equilibrium state, where infection remains at a level that does not affect plant viability. © 2016 BSPP AND JOHN WILEY & SONS LTD.

  14. Do induced responses mediate the ecological interactions between the specialist herbivores and phytopathogens of an alpine plant?

    Science.gov (United States)

    Röder, Gregory; Rahier, Martine; Naisbit, Russell E

    2011-05-04

    Plants are not passive victims of the myriad attackers that rely on them for nutrition. They have a suite of physical and chemical defences, and are even able to take advantage of the enemies of their enemies. These strategies are often only deployed upon attack, so may lead to indirect interactions between herbivores and phytopathogens. In this study we test for induced responses in wild populations of an alpine plant (Adenostyles alliariae) that possesses constitutive chemical defence (pyrrolizidine alkaloids) and specialist natural enemies (two species of leaf beetle, Oreina elongata and Oreina cacaliae, and the phytopathogenic rust Uromyces cacaliae). Plants were induced in the field using chemical elicitors of the jasmonic acid (JA) and salicylic acid (SA) pathways and monitored for one month under natural conditions. There was evidence for induced resistance, with lower probability and later incidence of attack by beetles in JA-induced plants and of rust infection in SA-induced plants. We also demonstrate ecological cross-effects, with reduced fungal attack following JA-induction, and a cost of SA-induction arising from increased beetle attack. As a result, there is the potential for negative indirect effects of the beetles on the rust, while in the field the positive indirect effect of the rust on the beetles appears to be over-ridden by direct effects on plant nutritional quality. Such interactions resulting from induced susceptibility and resistance must be considered if we are to exploit plant defences for crop protection using hormone elicitors or constitutive expression. More generally, the fact that induced defences are even found in species that possess constitutively-expressed chemical defence suggests that they may be ubiquitous in higher plants.

  15. Do induced responses mediate the ecological interactions between the specialist herbivores and phytopathogens of an alpine plant?

    Directory of Open Access Journals (Sweden)

    Gregory Röder

    2011-05-01

    Full Text Available Plants are not passive victims of the myriad attackers that rely on them for nutrition. They have a suite of physical and chemical defences, and are even able to take advantage of the enemies of their enemies. These strategies are often only deployed upon attack, so may lead to indirect interactions between herbivores and phytopathogens. In this study we test for induced responses in wild populations of an alpine plant (Adenostyles alliariae that possesses constitutive chemical defence (pyrrolizidine alkaloids and specialist natural enemies (two species of leaf beetle, Oreina elongata and Oreina cacaliae, and the phytopathogenic rust Uromyces cacaliae. Plants were induced in the field using chemical elicitors of the jasmonic acid (JA and salicylic acid (SA pathways and monitored for one month under natural conditions. There was evidence for induced resistance, with lower probability and later incidence of attack by beetles in JA-induced plants and of rust infection in SA-induced plants. We also demonstrate ecological cross-effects, with reduced fungal attack following JA-induction, and a cost of SA-induction arising from increased beetle attack. As a result, there is the potential for negative indirect effects of the beetles on the rust, while in the field the positive indirect effect of the rust on the beetles appears to be over-ridden by direct effects on plant nutritional quality. Such interactions resulting from induced susceptibility and resistance must be considered if we are to exploit plant defences for crop protection using hormone elicitors or constitutive expression. More generally, the fact that induced defences are even found in species that possess constitutively-expressed chemical defence suggests that they may be ubiquitous in higher plants.

  16. Probabilistic Flood Defence Assessment Tools

    Directory of Open Access Journals (Sweden)

    Slomp Robert

    2016-01-01

    Full Text Available The WTI2017 project is responsible for the development of flood defence assessment tools for the 3600 km of Dutch primary flood defences, dikes/levees, dunes and hydraulic structures. These tools are necessary, as per January 1st 2017, the new flood risk management policy for the Netherlands will be implemented. Then, the seven decades old design practice (maximum water level methodology of 1958 and two decades old safety standards (and maximum hydraulic load methodology of 1996 will formally be replaced by a more risked based approach for the national policy in flood risk management. The formal flood defence assessment is an important part of this new policy, especially for flood defence managers, since national and regional funding for reinforcement is based on this assessment. This new flood defence policy is based on a maximum allowable probability of flooding. For this, a maximum acceptable individual risk was determined at 1/100 000 per year, this is the probability of life loss of for every protected area in the Netherlands. Safety standards of flood defences were then determined based on this acceptable individual risk. The results were adjusted based on information from cost -benefit analysis, societal risk and large scale societal disruption due to the failure of critical infrastructure e.g. power stations. The resulting riskbased flood defence safety standards range from a 300 to a 100 000 year return period for failure. Two policy studies, WV21 (Safety from floods in the 21st century and VNK-2 (the National Flood Risk in 2010 provided the essential information to determine the new risk based safety standards for flood defences. The WTI2017 project will provide the safety assessment tools based on these new standards and is thus an essential element for the implementation of this policy change. A major issue to be tackled was the development of user-friendly tools, as the new assessment is to be carried out by personnel of the

  17. Plant responses to metal toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Briat, J.F. [Montpellier-2 Univ., 34 (France). Biochimie et physiologie moleculaire des plantes, CNRS, URA 2133; Lebrun, M. [Montpellier-2 Univ., 34 (France). Biochimie et physiologie vegetale appliquee

    1999-01-01

    Increased metal concentration in the soils, up to toxic levels, is becoming an important environmental problem. Safety rule evolution will require solutions in order to cope with food safety rules, and to freeze metal leakage from heavily metal-poisoned soils, such as those from industrial fallows. In this context, plants could serve to develop bio-assays in order to promote new standards, more realistic than the mass of a given metal per kg of soil, that does not consider the metal bio-disponibility. Plants could also be used for phyto-extraction and/or phyto-stabilization. To reach these objectives, a genetic approach could be useful to generate metal-tolerant plants with enough biomass. In this work is more particularly studied the plant responses to metal toxicity. Metal toxicity for living organisms involves oxidative and /or genotoxic mechanisms. Plant protection against metal toxicity occurs, at least in part, through control of root metal uptake and of long distance metal transport. Inside cells, proteins such as ferritins and metallothioneins, and glutathione-derived peptides named phyto-chelatins, participate in excess metal storage and detoxification. Low molecular weight organic molecules, mainly organic acids and amino acids and their derivatives, also play an important role in plant metal homeostasis. When these systems are overloaded, oxidative stress defense mechanisms are activated. Molecular and cellular knowledge of these processes will be necessary to improve plant metal resistance. Occurrence of naturally tolerant plants which hyper accumulate metals provides helpful tools for this research. (authors) 130 refs.

  18. Saltmarsh plant responses to eutrophication.

    Science.gov (United States)

    Johnson, David Samuel; Warren, R Scott; Deegan, Linda A; Mozdzer, Thomas J

    2016-12-01

    In saltmarsh plant communities, bottom-up pressure from nutrient enrichment is predicted to increase productivity, alter community structure, decrease biodiversity, and alter ecosystem functioning. Previous work supporting these predictions has been based largely on short-term, plot-level (e.g., 1-300 m 2 ) studies, which may miss landscape-level phenomena that drive ecosystem-level responses. We implemented an ecosystem-scale, nine-year nutrient experiment to examine how saltmarsh plants respond to simulated conditions of coastal eutrophication. Our study differed from previous saltmarsh enrichment studies in that we applied realistic concentrations of nitrate (70-100 μM NO 3 - ), the most common form of coastal nutrient enrichment, via tidal water at the ecosystem scale (~60,000 m 2 creeksheds). Our enrichments added a total of 1,700 kg N·creek -1 ·yr -1 , which increased N loading 10-fold vs. reference creeks (low-marsh, 171 g N·m -2 ·yr -1 ; high-marsh, 19 g N·m -2 ·yr -1 ). Nutrients increased the shoot mass and height of low marsh, tall Spartina alterniflora; however, declines in stem density resulted in no consistent increase in aboveground biomass. High-marsh plants S. patens and stunted S. alterniflora did not respond consistently to enrichment. Nutrient enrichment did not shift community structure, contrary to the prediction of nutrient-driven dominance of S. alterniflora and Distichlis spicata over S. patens. Our mild responses may differ from the results of previous studies for a number of reasons. First, the limited response of the high marsh may be explained by loading rates orders of magnitude lower than previous work. Low loading rates in the high marsh reflect infrequent inundation, arguing that inundation patterns must be considered when predicting responses to estuarine eutrophication. Additionally, we applied nitrate instead of the typically used ammonium, which is energetically favored over nitrate for plant uptake. Thus, the

  19. Parasitism by Cuscuta pentagona sequentially induces JA and SA defence pathways in tomato.

    Science.gov (United States)

    Runyon, Justin B; Mescher, Mark C; Felton, Gary W; De Moraes, Consuelo M

    2010-02-01

    While plant responses to herbivores and pathogens are well characterized, responses to attack by other plants remain largely unexplored. We measured phytohormones and C(18) fatty acids in tomato attacked by the parasitic plant Cuscuta pentagona, and used transgenic and mutant plants to explore the roles of the defence-related phytohormones salicylic acid (SA) and jasmonic acid (JA). Parasite attachment to 10-day-old tomato plants elicited few biochemical changes, but a second attachment 10 d later elicited a 60-fold increase in JA, a 30-fold increase in SA and a hypersensitive-like response (HLR). Host age also influenced the response: neither Cuscuta seedlings nor established vines elicited a HLR in 10-day-old hosts, but both did in 20-day-old hosts. Parasites grew larger on hosts deficient in SA (NahG) or insensitive to JA [jasmonic acid-insensitive1 (jai1)], suggesting that both phytohormones mediate effective defences. Moreover, amounts of JA peaked 12 h before SA, indicating that defences may be coordinated via sequential induction of these hormones. Parasitism also induced increases in free linolenic and linoleic acids and abscisic acid. These findings provide the first documentation of plant hormonal signalling induced by a parasitic plant and show that tomato responses to C. pentagona display characteristics similar to both herbivore- and pathogen-induced responses.

  20. The structure of a purple acid phosphatase involved in plant growth and pathogen defence exhibits a novel immunoglobulin-like fold

    Directory of Open Access Journals (Sweden)

    Svetlana Vladimirovna Antonyuk

    2014-03-01

    Full Text Available Phosphatases function in the production, transport and recycling of inorganic phosphorus, which is crucial for cellular metabolism and bioenergetics, as well as in bacterial killing, since they are able to generate reactive oxygen species via Fenton chemistry. Diphosphonucleotide phosphatase/phosphodiesterase (PPD1, a glycoprotein plant purple acid phosphatase (PAP from yellow lupin seeds, contains a bimetallic Fe–Mn catalytic site which is most active at acidic pH. Unlike other plant PAPs, PPD1 cleaves the pyrophosphate bond in diphosphonucleotides and the phosphodiester bond in various phosphodiesters. The homohexameric organization of PPD1, as revealed by a 1.65 Å resolution crystal structure and confirmed by solution X-ray scattering, is unique among plant PAPs, for which only homodimers have previously been reported. A phosphate anion is bound in a bidentate fashion at the active site, bridging the Fe and Mn atoms in a binding mode similar to that previously reported for sweet potato PAP, which suggests that common features occur in their catalytic mechanisms. The N-terminal domain of PPD1 has an unexpected and unique fibronectin type III-like fold that is absent in other plant PAPs. Here, the in vitro DNA-cleavage activity of PPD1 is demonstrated and it is proposed that the fibronectin III-like domain, which `overhangs' the active site, is involved in DNA selectivity, binding and activation. The degradation of DNA by PPD1 implies a role for PPD1 in plant growth and repair and in pathogen defence.

  1. Civil defence abroad. Pt. 3: The Warsaw Pact countries

    International Nuclear Information System (INIS)

    Schirrmeister, K.G.; Hofmann, H.

    1988-01-01

    Civil defence forms part of the national defence of the G.D.R., and belongs since 1976 to the responsibility of the Defence Ministry. Civil defence service is equal to military service. Civil defence services are organised on a territorial basis and a production-oriented basis: Double concept. Construction of shelters is propagated for 30 years now, maintenance of existing buildings is an obligation since 1965. Principles (triage) of military medical service are applied, and are valid for students and post-graduate medical training. Civil defence training is required in school and industry. Civil defence expenditure is increasing, although there is little acceptance by the population. The issue presents extensive documentation. - Civil defence in the Soviet Union covers services in times of peace and of war. Defence measures are prepared and held up to date in the entire territory. The civil defence service belongs to the responsibility of the Council of Ministers, and the deputy minister of defence is the head of services. The training schedules and principles are laid down by the Central Committee of the Communist Party, the government, and local party organisations and governmental authorities. Civil defence training is a general obligation for all citizens over 8 years of age. The main goal is: Protection of the population as the production force, of the economy, and resources. (orig.) [de

  2. Defence reactions of plants to fungal pathogens: principles and perspectives, using powdery mildew on cereals as an example

    Science.gov (United States)

    Heitefuss, Rudolf

    2001-06-01

    Diseases of crop plants may lead to considerable yield losses. To control fungal diseases, fungicides are used extensively in present-day agricultural production. In order to reduce such external inputs, cultivars with natural resistance to important fungal pathogens are recommended in systems of integrated plant protection. Basic research, including genetics and molecular methods, is required to elucidate the mechanisms by which plants react to an attack by fungal pathogens and successfully defend themselves. This review examines our knowledge with respect to the multicomponent systems of resistance in plants, using powdery mildew on barley as an example. In addition, the question is adressed whether systemic acquired resistance and plants with transgenic resistance may be utilized in future plant protection strategies.

  3. Plant pathology: monitoring a pathogen-targeted host protein.

    Science.gov (United States)

    Ellis, Jeff; Dodds, Peter

    2003-05-13

    A plant protein RIN4 is targeted and modified by bacterial pathogens as part of the disease process. At least two host resistance proteins monitor this pathogen interference and trigger the plant's defence responses.

  4. The bile acid deoxycholate elicits defences in Arabidopsis and reduces bacterial infection.

    Science.gov (United States)

    Zarattini, Marco; Launay, Alban; Farjad, Mahsa; Wénès, Estelle; Taconnat, Ludivine; Boutet, Stéphanie; Bernacchia, Giovanni; Fagard, Mathilde

    2017-05-01

    Disease has an effect on crop yields, causing significant losses. As the worldwide demand for agricultural products increases, there is a need to pursue the development of new methods to protect crops from disease. One mechanism of plant protection is through the activation of the plant immune system. By exogenous application, 'plant activator molecules' with elicitor properties can be used to activate the plant immune system. These defence-inducing molecules represent a powerful and often environmentally friendly tool to fight pathogens. We show that the secondary bile acid deoxycholic acid (DCA) induces defence in Arabidopsis and reduces the proliferation of two bacterial phytopathogens: Erwinia amylovora and Pseudomonas syringae pv. tomato. We describe the global defence response triggered by this new plant activator in Arabidopsis at the transcriptional level. Several induced genes were selected for further analysis by quantitative reverse transcription-polymerase chain reaction. We describe the kinetics of their induction and show that abiotic stress, such as moderate drought or nitrogen limitation, does not impede DCA induction of defence. Finally, we investigate the role in the activation of defence by this bile acid of the salicylic acid biosynthesis gene SID2, of the receptor-like kinase family genes WAK1-3 and of the NADPH oxidase-encoding RbohD gene. Altogether, we show that DCA constitutes a promising molecule for plant protection which can induce complementary lines of defence, such as callose deposition, reactive oxygen species accumulation and the jasmonic acid and salicylic acid signalling pathways. © 2016 BSPP AND JOHN WILEY & SONS LTD.

  5. To each its own: differential response of specialist and generalist herbivores to plant defence in willows

    Czech Academy of Sciences Publication Activity Database

    Volf, Martin; Hrček, Jan; Julkunen-Titto, R.; Novotný, Vojtěch

    2015-01-01

    Roč. 84, č. 4 (2015), s. 1123-1132 ISSN 0021-8790 R&D Projects: GA ČR(CZ) GA14-04258S Grant - others:GA JU(CZ) 156/2013/P; European Social fund(CZ) CZ.1.07/2.3.00/20.0064 Institutional support: RVO:60077344 Keywords : community structure * defensive traits * herbivory Subject RIV: EH - Ecology , Behaviour Impact factor: 4.827, year: 2015 http://onlinelibrary.wiley.com/doi/10.1111/1365-2656.12349/pdf

  6. Leaf Colour as a Signal of Chemical Defence to Insect Herbivores in Wild Cabbage (Brassica oleracea.

    Directory of Open Access Journals (Sweden)

    Jonathan P Green

    Full Text Available Leaf colour has been proposed to signal levels of host defence to insect herbivores, but we lack data on herbivory, leaf colour and levels of defence for wild host populations necessary to test this hypothesis. Such a test requires measurements of leaf spectra as they would be sensed by herbivore visual systems, as well as simultaneous measurements of chemical defences and herbivore responses to leaf colour in natural host-herbivore populations. In a large-scale field survey of wild cabbage (Brassica oleracea populations, we show that variation in leaf colour and brightness, measured according to herbivore spectral sensitivities, predicts both levels of chemical defences (glucosinolates and abundance of specialist lepidopteran (Pieris rapae and hemipteran (Brevicoryne brassicae herbivores. In subsequent experiments, P. rapae larvae achieved faster growth and greater pupal mass when feeding on plants with bluer leaves, which contained lower levels of aliphatic glucosinolates. Glucosinolate-mediated effects on larval performance may thus contribute to the association between P. rapae herbivory and leaf colour observed in the field. However, preference tests found no evidence that adult butterflies selected host plants based on leaf coloration. In the field, B. brassicae abundance varied with leaf brightness but greenhouse experiments were unable to identify any effects of brightness on aphid preference or performance. Our findings suggest that although leaf colour reflects both levels of host defences and herbivore abundance in the field, the ability of herbivores to respond to colour signals may be limited, even in species where performance is correlated with leaf colour.

  7. Plants having modified response to ethylene

    Science.gov (United States)

    Meyerowitz, E.M.; Chang, C.; Bleecker, A.B.

    1997-11-18

    The invention includes transformed plants having at least one cell transformed with a modified ETR nucleic acid. Such plants have a phenotype characterized by a decrease in the response of at least one transformed plant cell to ethylene as compared to a plant not containing the transformed plant cell. Tissue and/or temporal specificity for expression of the modified ETR nucleic acid is controlled by selecting appropriate expression regulation sequences to target the location and/or time of expression of the transformed nucleic acid. The plants are made by transforming at least one plant cell with an appropriate modified ETR nucleic acid, regenerating plants from one or more of the transformed plant cells and selecting at least one plant having the desired phenotype. 31 figs.

  8. Plant responses to insect egg deposition

    NARCIS (Netherlands)

    Hilker, M.; Fatouros, N.E.

    2015-01-01

    Plants can respond to insect egg deposition and thus resist attack by herbivorous insects from the beginning of the attack, egg deposition. We review ecological effects of plant responses to insect eggs and differentiate between egg-induced plant defenses that directly harm the eggs and indirect

  9. Genome wide expression profiling reveals suppression of host defence responses during colonisation by Neisseria meningitides but not N. lactamica.

    Directory of Open Access Journals (Sweden)

    Hazel En En Wong

    Full Text Available Both Neisseria meningitidis and the closely related bacterium Neisseria lactamica colonise human nasopharyngeal mucosal surface, but only N. meningitidis invades the bloodstream to cause potentially life-threatening meningitis and septicaemia. We have hypothesised that the two neisserial species differentially modulate host respiratory epithelial cell gene expression reflecting their disease potential. Confluent monolayers of 16HBE14 human bronchial epithelial cells were exposed to live and/or dead N. meningitidis (including capsule and pili mutants and N. lactamica, and their transcriptomes were compared using whole genome microarrays. Changes in expression of selected genes were subsequently validated using Q-RT-PCR and ELISAs. Live N. meningitidis and N. lactamica induced genes involved in host energy production processes suggesting that both bacterial species utilise host resources. N. meningitidis infection was associated with down-regulation of host defence genes. N. lactamica, relative to N. meningitidis, initiates up-regulation of proinflammatory genes. Bacterial secreted proteins alone induced some of the changes observed. The results suggest N. meningitidis and N. lactamica differentially regulate host respiratory epithelial cell gene expression through colonisation and/or protein secretion, and that this may contribute to subsequent clinical outcomes associated with these bacteria.

  10. Synergism in the effect of prior jasmonic acid application on herbivore-induced volatile emission by Lima bean plants: transcription of a monoterpene synthase gene and volatile emission

    NARCIS (Netherlands)

    Menzel, T.R.; Weldegergis, B.T.; David, A.; Boland, W.; Gols, R.; Loon, van J.J.A.; Dicke, M.

    2014-01-01

    Jasmonic acid (JA) plays a central role in induced plant defence e.g. by regulating the biosynthesis of herbivore-induced plant volatiles that mediate the attraction of natural enemies of herbivores. Moreover, exogenous application of JA can be used to elicit plant defence responses similar to those

  11. Diverse opportunities in defence

    Science.gov (United States)

    Brown, Gareth

    2016-08-01

    Working at the UK's defence laboratory gives Gareth Brown the ability to apply his physics and mathematics knowledge to real-world applications - and not necessarily in the ways you might expect. This article is Crown copyright

  12. From Defence To Development

    International Development Research Centre (IDRC) Digital Library (Canada)

    From this perspective, high defence expenditure has been compared to dismantling ...... availability exceed evaporative demand and a state of permanent drought ...... In October 1993, South African authorities seized a container on a plot near ...

  13. Ecological mechanisms for the coevolution of mating systems and defence.

    Science.gov (United States)

    Campbell, Stuart A

    2015-02-01

    The diversity of flowering plants is evident in two seemingly unrelated aspects of life history: sexual reproduction, exemplified by the stunning variation in flower form and function, and defence, often in the form of an impressive arsenal of secondary chemistry. Researchers are beginning to appreciate that plant defence and reproduction do not evolve independently, but, instead, may have reciprocal and interactive (coevolutionary) effects on each other. Understanding the mechanisms for mating-defence interactions promises to broaden our understanding of how ecological processes can generate these two rich sources of angiosperm diversity. Here, I review current research on the role of herbivory as a driver of mating system evolution, and the role of mating systems in the evolution of defence strategies. I outline different ecological mechanisms and processes that could generate these coevolutionary patterns, and summarize theoretical and empirical support for each. I provide a conceptual framework for linking plant defence with mating system theory to better integrate these two research fields.

  14. An allele of Arabidopsis COI1 with hypo- and hypermorphic phenotypes in plant growth, defence and fertility.

    Directory of Open Access Journals (Sweden)

    Albor Dobón

    Full Text Available Resistance to biotrophic pathogens is largely dependent on the hormone salicylic acid (SA while jasmonic acid (JA regulates resistance against necrotrophs. JA negatively regulates SA and is, in itself, negatively regulated by SA. A key component of the JA signal transduction pathway is its receptor, the COI1 gene. Mutations in this gene can affect all the JA phenotypes, whereas mutations in other genes, either in JA signal transduction or in JA biosynthesis, lack this general effect. To identify components of the part of the resistance against biotrophs independent of SA, a mutagenised population of NahG plants (severely depleted of SA was screened for suppression of susceptibility. The screen resulted in the identification of intragenic and extragenic suppressors, and the results presented here correspond to the characterization of one extragenic suppressor, coi1-40. coi1-40 is quite different from previously described coi1 alleles, and it represents a strategy for enhancing resistance to biotrophs with low levels of SA, likely suppressing NahG by increasing the perception to the remaining SA. The phenotypes of coi1-40 lead us to speculate about a modular function for COI1, since we have recovered a mutation in COI1 which has a number of JA-related phenotypes reduced while others are equal to or above wild type levels.

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

    Directory of Open Access Journals (Sweden)

    Benoît eDrogue

    2014-11-01

    Full Text Available Cooperation involving Plant Growth-Promoting Rhizobacteria results in improvements of plant growth and health. While pathogenic and symbiotic interactions are known to induce transcriptional changes for genes related to plant defence and development, little is known about the impact of phytostimulating rhizobacteria on plant gene expression. This study aims at identifying genes significantly regulated in rice roots upon Azospirillum inoculation, considering possible favored interaction between a strain and its original host cultivar. Genome-wide analyses of Oryza sativa japonica cultivars Cigalon and Nipponbare were performed, by using microarrays, seven days post inoculation with A. lipoferum 4B (isolated from Cigalon or Azospirillum sp. B510 (isolated from Nipponbare and compared to the respective non-inoculated condition. A total of 7,384 genes were significantly regulated, which represent about 16 % of total rice genes. A set of 34 genes is regulated by both Azospirillum strains in both cultivars, including a gene orthologous to PR10 of Brachypodium, and these could represent plant markers of Azospirillum-rice interactions. The results highlight a strain-dependent response of rice, with 83 % of the differentially expressed genes being classified as combination-specific. Whatever the combination, most of the differentially expressed genes are involved in primary metabolism, transport, regulation of transcription and protein fate. When considering genes involved in response to stress and plant defence, it appears that strain B510, a strain displaying endophytic properties, leads to the repression of a wider set of genes than strain 4B. Individual genotypic variations could be the most important driving force of rice roots gene expression upon Azospirillum inoculation. Strain-dependent transcriptional changes observed for genes related to auxin and ethylene signalling highlight the complexity of hormone signalling networks in the Azospirillum

  16. Plants' responses to drought and shade environments

    African Journals Online (AJOL)

    전병기

    factors affect plants' growth, morphology, physiology and biochemistry. Many research works .... Hardwood and Conifer tree species n central Wisconsin: Influence of light regime and .... Ecotypic variation in response to light spectra in Scots ...

  17. Environmental pollution and plant responses

    Energy Technology Data Exchange (ETDEWEB)

    Agrawal, S.B.; Agrawal, M. [Banaras Hindu Univ. (India)

    1999-11-01

    This is a comprehensive book that presents and analyses the most current research on the causal factors contributing to the deteriorating environmental quality and its effect on plant performance. It presents a holistic approach to environmental problem throughout the world; covers recent trends in understanding mechanism of action individually and in combination with other factors; evaluates recent trends of information on global climatic change issues and its consequences; and gives management strategies to be followed for abating the problem.

  18. The Apoplastic Secretome of Trichoderma virens During Interaction With Maize Roots Shows an Inhibition of Plant Defence and Scavenging Oxidative Stress Secreted Proteins

    Directory of Open Access Journals (Sweden)

    Guillermo Nogueira-Lopez

    2018-04-01

    Full Text Available In Nature, almost every plant is colonized by fungi. Trichoderma virens is a biocontrol fungus which has the capacity to behave as an opportunistic plant endophyte. Even though many plants are colonized by this symbiont, the exact mechanisms by which Trichoderma masks its entrance into its plant host remain unknown, but likely involve the secretion of different families of proteins into the apoplast that may play crucial roles in the suppression of plant immune responses. In this study, we investigated T. virens colonization of maize roots under hydroponic conditions, evidencing inter- and intracellular colonization by the fungus and modifications in root morphology and coloration. Moreover, we show that upon host penetration, T. virens secretes into the apoplast an arsenal of proteins to facilitate inter- and intracellular colonization of maize root tissues. Using a gel-free shotgun proteomics approach, 95 and 43 secretory proteins were identified from maize and T. virens, respectively. A reduction in the maize secretome (36% was induced by T. virens, including two major groups, glycosyl hydrolases and peroxidases. Furthermore, T. virens secreted proteins were mainly involved in cell wall hydrolysis, scavenging of reactive oxygen species and secondary metabolism, as well as putative effector-like proteins. Levels of peroxidase activity were reduced in the inoculated roots, suggesting a strategy used by T. virens to manipulate host immune responses. The results provide an insight into the crosstalk in the apoplast which is essential to maintain the T. virens-plant interaction.

  19. Reduction of seismic response in breeder plants

    International Nuclear Information System (INIS)

    Tajirian, F.F.; Somes, N.F.; Todeschini, R.A.

    1984-01-01

    Thin-walled vessels to be used in the Nuclear Steam Supply Systems (NSSS) of future LMFBR's will be more sensitive to seismic excitation than their equivalents used in conventional LWR plants. Optimization studies of building arrangement have indicated that embedment of future plants may be one feasible strategy for reducing seismic response. This paper presents the results of a three-dimensional soil-structure interaction analysis using the computer program SASSI. Two types of embedded buildings are considered: full embedment of the nuclear island, and embedment of the reactor cavity alone. A comparison, between the response of the embedded structure with that of a plant supported on the surface, indicates that the seismic response at the reactor vessel support ledge can be lowered by embedment of either the entire nuclear island or the reactor cavity alone. This reduction is larger when the plant is embedded in a softer site due to the increased effect of soil-structure interaction

  20. How predictable are the behavioral responses of insects to herbivore induced changes in plants? Responses of two congeneric thrips to induced cotton plants.

    Directory of Open Access Journals (Sweden)

    Rehan Silva

    Full Text Available Changes in plants following insect attack are referred to as induced responses. These responses are widely viewed as a form of defence against further insect attack. In the current study we explore whether it is possible to make generalizations about induced plant responses given the unpredictability and variability observed in insect-plant interactions. Experiments were conducted to test for consistency in the responses of two congeneric thrips, Frankliniella schultzei Trybom and Frankliniella occidentalis Pergrande (Thysanoptera: Thripidae to cotton seedlings (Gossypium hirsutum Linneaus (Malvales: Malvaceae damaged by various insect herbivores. In dual-choice experiments that compared intact and damaged cotton seedlings, F. schultzei was attracted to seedlings damaged by Helicoverpa armigera (Hübner (Lepidoptera: Noctuidae, Tetranychus urticae (Koch (Trombidiforms: Tetranychidae, Tenebrio molitor Linnaeus (Coleoptera: Tenebrionidae, F. schultzei and F. occidentalis but not to mechanically damaged seedlings. In similar tests, F. occidentalis was attracted to undamaged cotton seedlings when simultaneously exposed to seedlings damaged by H. armigera, T. molitor or F. occidentalis. However, when exposed to F. schultzei or T. urticae damaged plants, F. occidentalis was more attracted towards damaged plants. A quantitative relationship was also apparent, F. schultzei showed increased attraction to damaged seedlings as the density of T. urticae or F. schultzei increased. In contrast, although F. occidentalis demonstrated increased attraction to plants damaged by higher densities of T. urticae, there was a negative relationship between attraction and the density of damaging conspecifics. Both species showed greater attraction to T. urticae damaged seedlings than to seedlings damaged by conspecifics. Results demonstrate that the responses of both species of thrips were context dependent, making generalizations difficult to formulate.

  1. Defence in depth perspectives

    International Nuclear Information System (INIS)

    Veneau, Tania; Ferrier, Agnes; Barbaud, Jean

    2017-01-01

    complex technical solutions. The independence between DiD levels should not be an absolute design principle but risk analysis should be used to identify the areas where this would be necessary. For instance, devoting equipments/systems to a single level (without possibility of sharing them with other levels) could negatively impact the overall plant safety: it might complexify the facility and affect operator reliability (even if the operators are trained to face accidental situations, they are more familiar with normal system operation on a daily basis). The paper presents first how the concept of DiD evolved over time, the link with the barriers notion, the current consensus on DiD definitions obtained despite some differences observed between standards (eg. IAEA and WENRA definitions), and discusses the subjects identified above, before raising perspectives on how to achieve a sufficient independence of DiD levels. They are based on a minimum level of redundancy, on physical separation, on diversity (even though they are not systematically recommended), but also on strengthening the robustness of defence lines. In practice, DiD concept should be implemented in a manner that ensures that each level is effective in meeting its specific objective. (author)

  2. New materials in defence

    International Nuclear Information System (INIS)

    Khan, Sikandar S.; Khan, Shahid A.; Butt, N.M.

    1992-01-01

    National defence is very important and always needs new such materials which have technological and socio-economic development of human society. The types of materials used by a society reflect its level of sophistication. These modern materials are basically the same conventional materials but with a greater knowledge content which include superalloys, modern polymers, engineering ceramics and the advanced composite. The production and use of new materials is playing and important role in the recent development in the defence industry. (A.B.)

  3. Do plants and animals differ in phenotypic plasticity?

    Indian Academy of Sciences (India)

    Unknown

    fits, of a plastic versus non-plastic phenotype in plants and animals. [Renee M Borges ... polyphenol oxidase and other oxidative enzymes in the defence repertoire of .... males in response to environmental stress (Cremer and. Heinze 2003).

  4. Native plant community response to alien plant invasion and removal

    Directory of Open Access Journals (Sweden)

    Jara ANDREU

    2011-01-01

    Full Text Available Given the potential ecological impacts of invasive species, removal of alien plants has become an important management challenge and a high priority for environmental managers. To consider that a removal effort has been successful requires both, the effective elimination of alien plants and the restoration of the native plant community back to its historical composition and function. We present a conceptual framework based on observational and experimental data that compares invaded, non-invaded and removal sites to quantify invaders’ impacts and native plant recover after their removal. We also conduct a meta-analysis to quantitatively evaluate the impacts of plant invaders and the consequences of their removal on the native plant community, across a variety of ecosystems around the world. Our results that invasion by alien plants is responsible for a local decline in native species richness and abundance. Our analysis also provides evidence that after removal, the native vegetation has the potential to recover to a pre-invasion target state. Our review reveal that observational and experimental approaches are rarely used in concert, and that reference sites are scarcely employed to assess native species recovery after removal. However, we believe that comparing invaded, non-invaded and removal sites offer the opportunity to obtain scientific information with relevance for management.

  5. TNO and CBRN defence

    NARCIS (Netherlands)

    2015-01-01

    Within the Defence, Safety & Security branch of TNO a dedicated department focuses on Chemical, Biological, Radiological and Nuclear (CBRN) Protection. This is a world class research department consisting of about 50 people and a High Tox laboratory that is the only facility in The Netherlands that

  6. NATO Defence Planning Process. Implications for defence posture

    Directory of Open Access Journals (Sweden)

    Paweł Fleischer

    2015-12-01

    Full Text Available The NATO Defence Planning Process (NDPP is the most important element affecting the Alliance's defence posture. Under the process states commit themselves to provide capabilities and forces required to fulfil NATO missions, defined in the NATO Strategic Concept. The NDPP directly affects national defence plans by harmonizing them with identified security and defence objectives as well by influencing development of the novel national defence capabilities. The emergence of new threats in the NATO environment, demands modifications in the defense planning process and establishing new goals for the Alliance. Enhancement of the NDPP should be priority during the time of unrest.

  7. Thrips advisor: exploiting thrips-induced defences to combat pests on crops.

    Science.gov (United States)

    Steenbergen, Merel; Abd-El-Haliem, Ahmed; Bleeker, Petra; Dicke, Marcel; Escobar-Bravo, Rocio; Cheng, Gang; Haring, Michel A; Kant, Merijn R; Kappers, Iris; Klinkhamer, Peter G L; Leiss, Kirsten A; Legarrea, Saioa; Macel, Mirka; Mouden, Sanae; Pieterse, Corné M J; Sarde, Sandeep J; Schuurink, Robert C; De Vos, Martin; Van Wees, Saskia C M; Broekgaarden, Colette

    2018-04-09

    Plants have developed diverse defence mechanisms to ward off herbivorous pests. However, agriculture still faces estimated crop yield losses ranging from 25% to 40% annually. These losses arise not only because of direct feeding damage, but also because many pests serve as vectors of plant viruses. Herbivorous thrips (Thysanoptera) are important pests of vegetable and ornamental crops worldwide, and encompass virtually all general problems of pests: they are highly polyphagous, hard to control because of their complex lifestyle, and they are vectors of destructive viruses. Currently, control management of thrips mainly relies on the use of chemical pesticides. However, thrips rapidly develop resistance to these pesticides. With the rising demand for more sustainable, safer, and healthier food production systems, we urgently need to pinpoint the gaps in knowledge of plant defences against thrips to enable the future development of novel control methods. In this review, we summarize the current, rather scarce, knowledge of thrips-induced plant responses and the role of phytohormonal signalling and chemical defences in these responses. We describe concrete opportunities for breeding resistance against pests such as thrips as a prototype approach for next-generation resistance breeding.

  8. Investigation of the effect of a panel of model hepatotoxins on the Nrf2-Keap1 defence response pathway in CD-1 mice

    International Nuclear Information System (INIS)

    Randle, Laura E.; Goldring, Chris E.P.; Benson, Craig A.; Metcalfe, Peter N.; Kitteringham, Neil R.; Park, B. Kevin; Williams, Dominic P.

    2008-01-01

    The Keap1-Nrf2-ARE signalling pathway has emerged as an important regulator of the mammalian defence system to enable detoxification and clearance of foreign chemicals. Recent studies by our group using paracetamol (APAP), diethylmaleate and buthionine sulphoximine have shown that for a given xenobiotic molecule, Nrf2 induction in the murine liver is associated with protein reactivity and glutathione depletion. Here, we have investigated, in vivo, whether the ability of four murine hepatotoxins, paracetamol, bromobenzene (BB), carbon tetrachloride (CCl 4 ) and furosemide (FS) to deplete hepatic glutathione (GSH) is related to induction of hepatic Nrf2 nuclear translocation and Nrf2-dependent gene expression. Additionally, we studied whether hepatic Nrf2 nuclear translocation is a general response during the early stages of acute hepatic chemical stress in vivo. Male CD-1 mice were administered APAP (3.5 mmol/kg), FS (1.21 mmol/kg), BB (4.8 mmol/kg) and CCl 4 (1 mmol/kg) for 1, 5 and 24 h. Each compound elicited significant serum ALT increases after 24 h (ALT U/L: APAP, 3036 ± 1462; BB, 5308 ± 2210; CCl 4 , 5089 ± 1665; FS, 2301 ± 1053), accompanied by centrilobular damage as assessed by histopathology. Treatment with APAP also elicited toxicity at a much earlier time point (5 h) than the other hepatotoxins (ALT U/L: APAP, 1780 ± 661; BB, 161 ± 15; CCl 4 , 90 ± 23; FS, 136 ± 27). Significant GSH depletion was seen with APAP (9.6 ± 1.7% of control levels) and BB (52.8 ± 6.2% of control levels) 1 h after administration, but not with FS and CCl 4 . Western Blot analysis revealed an increase in nuclear Nrf2, 1 h after administration of BB (209 ± 10% control), CCl 4 (146 ± 3% control) and FS (254 ± 41% control), however this was significantly lower than the levels observed in the APAP-treated mice (462 ± 36% control). The levels of Nrf2-dependent gene induction were also analysed by quantitative real-time PCR and Western blotting. Treatment with APAP for 1

  9. Dynamic Frequency Response of Wind Power Plants

    DEFF Research Database (Denmark)

    Altin, Müfit

    according to their grid codes. In these scenarios particularly with high wind power penetration cases, conventional power plants (CPPs) such as old thermal power plants are planned to be replaced with wind power plants (WPPs). Consequently, the power system stability will be affected and the control...... to maintain sustainable and reliable operation of the power system for these targets, transmission system operators (TSOs) have revised the grid code requirements. Also, the TSOs are planning the future development of the power system with various wind penetration scenarios to integrate more wind power...... capability of WPPs would be investigated. The objective of this project is to analyze and identify the power system requirements for the synchronizing power support and inertial response control of WPPs in high wind power penetration scenarios. The dynamic frequency response of WPPs is realized...

  10. Genome-Wide Distribution, Organisation and Functional Characterization of Disease Resistance and Defence Response Genes across Rice Species

    Science.gov (United States)

    Singh, Sangeeta; Chand, Suresh; Singh, N. K.; Sharma, Tilak Raj

    2015-01-01

    The resistance (R) genes and defense response (DR) genes have become very important resources for the development of disease resistant cultivars. In the present investigation, genome-wide identification, expression, phylogenetic and synteny analysis was done for R and DR-genes across three species of rice viz: Oryza sativa ssp indica cv 93-11, Oryza sativa ssp japonica and wild rice species, Oryza brachyantha. We used the in silico approach to identify and map 786 R -genes and 167 DR-genes, 672 R-genes and 142 DR-genes, 251 R-genes and 86 DR-genes in the japonica, indica and O. brachyanth a genomes, respectively. Our analysis showed that 60.5% and 55.6% of the R-genes are tandemly repeated within clusters and distributed over all the rice chromosomes in indica and japonica genomes, respectively. The phylogenetic analysis along with motif distribution shows high degree of conservation of R- and DR-genes in clusters. In silico expression analysis of R-genes and DR-genes showed more than 85% were expressed genes showing corresponding EST matches in the databases. This study gave special emphasis on mechanisms of gene evolution and duplication for R and DR genes across species. Analysis of paralogs across rice species indicated 17% and 4.38% R-genes, 29% and 11.63% DR-genes duplication in indica and Oryza brachyantha, as compared to 20% and 26% duplication of R-genes and DR-genes in japonica respectively. We found that during the course of duplication only 9.5% of R- and DR-genes changed their function and rest of the genes have maintained their identity. Syntenic relationship across three genomes inferred that more orthology is shared between indica and japonica genomes as compared to brachyantha genome. Genome wide identification of R-genes and DR-genes in the rice genome will help in allele mining and functional validation of these genes, and to understand molecular mechanism of disease resistance and their evolution in rice and related species. PMID:25902056

  11. Defence White Paper 2013

    Science.gov (United States)

    2013-01-01

    nurtured, particularly in Australia’s highly competitive labour market. The Government recognises that Defence’s approach to its people must be... satisfaction , increase attraction and retention, improve cost-effectiveness and support the contemporary Total Force employment model. Defence White...improve job satisfaction and thereby increase attraction and retention in areas of critical skill. Recruiting 10.13 To ensure that we have the high

  12. Good and bad protons: genetic aspects of acidity stress responses in plants.

    Science.gov (United States)

    Shavrukov, Yuri; Hirai, Yoshihiko

    2016-01-01

    Physiological aspects of acidity stress in plants (synonymous with H(+) rhizotoxicity or low-pH stress) have long been a focus of research, in particular with respect to acidic soils where aluminium and H(+) rhizotoxicities often co-occur. However, toxic H(+) and Al(3+) elicit different response mechanisms in plants, and it is important to consider their effects separately. The primary aim of this review was to provide the current state of knowledge regarding the genetics of the specific reactions to low-pH stress in growing plants. A comparison of the results gleaned from quantitative trait loci analysis and global transcriptome profiling of plants in response to high proton concentrations revealed a two-stage genetic response: (i) in the short-term, proton pump H(+)-ATPases present the first barrier in root cells, allocating an excess of H(+) into either the apoplast or vacuole; the ensuing defence signaling system involves auxin, salicylic acid, and methyl jasmonate, which subsequently initiate expression of STOP and DREB transcription factors as well as chaperone ROF; (2) the long-term response includes other genes, such as alternative oxidase and type II NAD(P)H dehydrogenase, which act to detoxify dangerous reactive oxygen species in mitochondria, and help plants better manage the stress. A range of transporter genes including those for nitrate (NTR1), malate (ALMT1), and heavy metals are often up-regulated by H(+) rhizotoxicity. Expansins, cell-wall-related genes, the γ-aminobutyric acid shunt and biochemical pH-stat genes also reflect changes in cell metabolism and biochemistry in acidic conditions. However, the genetics underlying the acidity stress response of plants is complicated and only fragmentally understood. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  13. Plant community responses to climate change

    Energy Technology Data Exchange (ETDEWEB)

    Kongstad, J.

    2012-07-01

    ecosystem more resilient to the climatic treatments than expected. We also found that the amount of flowering culms of D. flexuosa increased in response to increased CO{sub 2}, whereas the seed germination success decreased. The bryophyte biomass and the nitrogen content decreased in response to nitrogen addition. Even such apparently minor changes might, given time, affect the plant composition and thereby possibly also the major ecosystem processes. Further, we observed changes in the aboveground plant composition in response to the climate manipulations at the Mols site, where C. vulgaris was regenerating after a disturbance. Here a decrease in biomass of the pioneer stage was seen, when subjected to the drought treatment compared to warmed and control treatments. I therefore conclude, that the stage of the C. vulgaris population as well as the magnitude and frequency of disturbances determine the effects of future climate change on the plant community in heathland ecosystems. (Author)

  14. Plant-parasitic nematodes: towards understanding molecular players in stress responses.

    Science.gov (United States)

    Gillet, François-Xavier; Bournaud, Caroline; Antonino de Souza Júnior, Jose Dijair; Grossi-de-Sa, Maria Fatima

    2017-03-01

    Plant-parasitic nematode interactions occur within a vast molecular plant immunity network. Following initial contact with the host plant roots, plant-parasitic nematodes (PPNs) activate basal immune responses. Defence priming involves the release in the apoplast of toxic molecules derived from reactive species or secondary metabolism. In turn, PPNs must overcome the poisonous and stressful environment at the plant-nematode interface. The ability of PPNs to escape this first line of plant immunity is crucial and will determine its virulence. Nematodes trigger crucial regulatory cytoprotective mechanisms, including antioxidant and detoxification pathways. Knowledge of the upstream regulatory components that contribute to both of these pathways in PPNs remains elusive. In this review, we discuss how PPNs probably orchestrate cytoprotection to resist plant immune responses, postulating that it may be derived from ancient molecular mechanisms. The review focuses on two transcription factors, DAF-16 and SKN-1 , which are conserved in the animal kingdom and are central regulators of cell homeostasis and immune function. Both regulate the unfolding protein response and the antioxidant and detoxification pathways. DAF-16 and SKN-1 target a broad spectrum of Caenorhabditis elegans genes coding for numerous protein families present in the secretome of PPNs. Moreover, some regulatory elements of DAF-16 and SKN-1 from C. elegans have already been identified as important genes for PPN infection. DAF-16 and SKN-1 genes may play a pivotal role in PPNs during parasitism. In the context of their hub status and mode of regulation, we suggest alternative strategies for control of PPNs through RNAi approaches. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company.

  15. Ethylenediurea as a potential tool in evaluating ozone phytotoxicity: a review study on physiological, biochemical and morphological responses of plants.

    Science.gov (United States)

    Tiwari, Supriya

    2017-06-01

    Present-day climate change scenario has intensified the problem of continuously increasing ground-level ozone (O 3 ), which is responsible for causing deleterious effects on growth and development of plants. Studies involving use of ethylenediurea (EDU), a chemical with antiozonant properties, have given some promising results in evaluating O 3 injury in plants. The use of EDU is especially advantageous in developing countries which face a more severe problem of ground-level O 3 , and technical O 3 -induced yield loss assessment techniques like open-top chambers cannot be used. Recent studies have detected a hormetic response of EDU on plants; i.e. treatment with higher EDU concentrations may or may not show any adverse effect on plants depending upon the experimental conditions. Although the mode of action of EDU is still debated, it is confirmed that EDU remains confined in the apoplastic regions. Certain studies indicate that EDU significantly affects the electron transport chain and has positive impact on the antioxidant defence machinery of the plants. However, the mechanism of protecting the yield of plants without significantly affecting photosynthesis is still questionable. This review discusses in details the probable mode of action of EDU on the basis of available data along with the impact of EDU on physiological, biochemical, growth and yield response of plants under O 3 stress. Data regarding the effect of EDU on plant 'omics' is highly insufficient and can form an important aspect of future EDU research.

  16. Plant control impact on IFR power plant passive safety response

    International Nuclear Information System (INIS)

    Vilim, R.B.

    1993-01-01

    A method is described for optimizing the closed-loop plant control strategy with respect to safety margins sustained in the unprotected upset response of a liquid metal reactor. The optimization is performed subject to the normal requirements for reactor startup, load change and compensation for reactivity changes over the cycle. The method provides a formal approach to the process of exploiting the innate self-regulating property of a metal fueled reactor to make it less dependent on operator action and less vulnerable to automatic control system fault and/or operator error

  17. Licensee responsibility for nuclear power plant safety

    International Nuclear Information System (INIS)

    Schneider, Horst

    2010-01-01

    Simple sentences easy to grasp are desirable in regulations and bans. However, in a legal system, their meaning must be unambiguous. Article 6, Paragraph 1 of the EURATOM Directive on a community framework for the nuclear safety of nuclear facilities of June 2009 states that 'responsibility for the nuclear safety of a nuclear facility is incumbent primarily on the licensee.' The draft 'Safety Criteria for Nuclear Power Plants, Revision D, April 2009' of the German Federal Ministry for the Environment, Nature Conservation, and Nuclear Safety (BMU) (A Module 1, 'Safety Criteria for Nuclear Power Plants: Basic Safety Criteria' / '0 Principles' Paragraph 2) reads: 'Responsibility for ensuring safety rests with the licensee. He shall give priority to compliance with the safety goal over the achievement of other operational objectives.' In addition, the existing rules and regulations, whose rank is equivalent to that of international regulations, assign priority to the safety goal to be pursued by the licensee over all other objectives of the company. The operator's responsibility for nuclear safety can be required and achieved only on the basis of permits granted, which must meet legal requirements. The operator's proximity to plant operation is the reason for his 'primary responsibility.' Consequently, verbatim incorporation of Article 6, Paragraph 1 of the EURATOM Directive would only be a superscript added to existing obligations of the operator - inclusive of a safety culture designed as an incentive to further 'the spirit of safety-related actions' - without any new legal contents and consequences. In the reasons of the regulation, this would have to be clarified in addition to the cryptic wording of 'responsibility.. primarily,' at the same time expressing that operators and authorities work together in a spirit of openness and trust. (orig.)

  18. Environmental Effects on Constitutive and Inducible Resin Defences of Pinus taeda

    Science.gov (United States)

    Maria L. Lombardero; Matthew P. Ayres; Peter L. Lorio; Jonathan J. Ruel

    2000-01-01

    The ecological literature abounds with studies of environmental effects on plant antiherbivore defences. While various models have been proposed (e.g. plant stress, optimal allocation, growth-differentiation balance), each has met with mixed support. One possible explanation for the mixed results is that constitutive and induced defences are differentialiy affected by...

  19. Host defence peptides in human burns.

    Science.gov (United States)

    Kaus, Aljoscha; Jacobsen, Frank; Sorkin, Michael; Rittig, Andrea; Voss, Bruno; Daigeler, Adrien; Sudhoff, Holger; Steinau, Hans-Ulrich; Steinstraesser, Lars

    2008-02-01

    The goal of this study was to analyse expression profiles of human epithelial host defence peptides in burned and unburned skin tissue, samples of which were obtained during debridements and snap-frozen in liquid nitrogen. Total RNA was isolated, and cDNA of epithelial host defence peptides and proteins (hCAP-18/LL-37, hBD1-hBD4, dermcidin, S100A7/psoriasin and RNAse7) was quantified by qRT-PCR. In situ hybridisation and immunohistochemical staining localised gene expression of hCAP-18/LL-37, hBD2 and hBD3 in histological sections. Most of the analysed host defence peptides and proteins showed higher mRNA levels in partial-thickness burns than in unburned tissue. In situ hybridisation revealed expression of hCAP-18/LL-37, hBD2 and hBD3 at the surface of burns that was independent of burn depth. However, the finding of higher host defence peptide gene expression rates does not correlate with the incidence of wound infection in burns. We hypothesise that the epithelial innate immune response in burns is complex.

  20. Evolutionary responses of native plant species to invasive plants : a review

    OpenAIRE

    Oduor, Ayub M. O.

    2013-01-01

    Strong competition from invasive plant species often leads to declines in abundances and may,in certain cases, cause localized extinctions of native plant species. Nevertheless, studies have shown that certain populations of native plant species can co-exist with invasive plant species, suggesting the possibility of adaptive evolutionary responses of those populations to the invasive plants. Empirical inference of evolutionary responses of the native plant species to invasive plants has invol...

  1. Accident management-defence in depth in Indian PHWRS

    International Nuclear Information System (INIS)

    Jagannad, V.B.L.; Reddy, V.V.; Hajela, Sameer; Bhatia, C.M.; Nair, Suma

    2015-01-01

    Defence in Depth (DiD) is the established safety principle for the design of Nuclear Power Plants (NPPs). Accident at Fukushima Dai-ichi had highlighted the importance of provisions at Level-4 and 5 of DiD. Post Fukushima accident, on-site measures have been strengthened for Indian Nuclear Power Plants. On procedural front, Accident Management Guidelines have been introduced to handle events more severe than design basis accidents. This paper elaborates enhancement of Defence in Depth provisions for Indian Nuclear Power Plants. (author)

  2. Does responsiveness to arbuscular mycorrhizas depend on plant invasive status?

    Science.gov (United States)

    1. Some posit invasive alien plants are less dependent on mycorrhizal associations than native plants, and thus weak mycorrhizal responsiveness may be a general mechanism of plant invasion. 2. Here, we tested whether mycorrhizal responsiveness varies by plant invasive status while controlling for ph...

  3. A proteomic approach to studying plant response to crenate broomrape (Orobanche crenata) in pea (Pisum sativum).

    Science.gov (United States)

    Angeles Castillejo, M; Amiour, Nardjis; Dumas-Gaudot, Eliane; Rubiales, Diego; Jorrín, Jesús V

    2004-06-01

    Crenate broomrape (Orobanche crenata) is a parasitic plant that threatens legume production in Mediterranean areas. Pea (Pisum sativum) is severely affected, and only moderate levels of genetic resistance have so far been identified. In the present work we selected the most resistant accession available (Ps 624) and compared it with a susceptible (Messire) cultivar. Experiments were performed by using pot and Petri dish bioassays, showing little differences in the percentage of broomrape seed germination induced by both genotypes, but a significant hamper in the number of successfully installed tubercles and their developmental stage in the Ps 624 compared to Messire. The protein profile of healthy and infected P. sativum root tissue were analysed by two-dimensional electrophoresis. Approximately 500 individual protein spots could be detected on silver stained gels. At least 22 different protein spots differentiated control, non-infected, Messire and Ps 624 accessions. Some of them were identified by MALDI-TOF mass spectrometry and database searching as cysteine proteinase, beta-1,3-glucanase, endochitinase, profucosidase, and ABA-responsive protein. Both qualitative and quantitative differences have been found among infected and non-infected root extracts. Thus, in the infected susceptible Messire genotype 34 spots were decreased, one increased and three newly detected, while in Ps 624, 15 spots were increased, three decreased and one newly detected. In response to the inoculation, proteins that correspond to enzymes of the carbohydrate metabolism (fructokinase, fructose-bisphosphate aldolase), nitrogen metabolism (ferredoxin-NADP reductase) and mitochondrial electronic chain transport (alternative oxidase 2) decreased in the susceptible check, while proteins that correspond to enzymes of the nitrogen assimilation pathway (glutamine synthetase) or typical pathogen defence, PR proteins, including beta-1,3-glucanase and peroxidases, increased in Ps 624. Results are

  4. Operational Analysis on Torpedo Defence

    NARCIS (Netherlands)

    Grootendorst, H.J.; Benders, F.P.A.; Fitski, H.J.; Veldhoven, E.R. van

    2007-01-01

    Since 1998, TNO Defence, Security and Safety has performed operational analysis with the Underwater Warfare Testbed, which provides an environment for evaluation and validation of systems, concepts, and tactics. On top of this testbed the Torpedo Defence System TestBed has been built to simulate

  5. Reinforcing Defence in Depth: A Practical Systemic Approach

    International Nuclear Information System (INIS)

    Watts, G.; Misak, J.

    2016-01-01

    The concept of defence in depth for ensuring nuclear safety of nuclear installations is often oversimplified and interpreted as a set of physical barriers, whose integrity is ensured by safety provisions in the form of the plant systems implemented independently at various levels of defence. However, the provisions established at each level of defence should in general terms include not only hardware components (active and passive systems), but more comprehensively, also inherent safety characteristics, safety margins, operating procedures and guidelines, quality assurance, safety culture, staff training, and many other organizational measures as parts of management of safety. Many of the above mentioned provisions belong to the category of human and organizational factors. While various hardware components are typically specific for different levels of defence, human and organizational factors may have an impact on several levels of defence. These factors are associated with large uncertainties and can result in latent weaknesses. Their implementation can negatively affect several levels of defence at the same time. The proposed paper will underline the need for a more comprehensive view of the defence in depth concept in order to provide a practical and effective tool for a systemic approach to safety. The paper will consist of two main parts. The first part will introduce a screening method developed by the IAEA as a tool for facilitating the assessment of the comprehensiveness of defence in depth. The method uses screening of safety provisions at five levels of defence to ensure integrity of the physical barriers and achievement of safety objectives at each level of defence. The second part of the paper will focus on human and organizational factors considered as provisions for reliable performance of safety functions. It will explain the significant shift in the demands on the human system between levels 3 and 4 of the defence in depth framework, and will

  6. Induction of wound-periderm-like tissue in Kalanchoe pinnata (Lam.) Pers. (Crassulaceae) leaves as a defence response to high UV-B radiation levels.

    Science.gov (United States)

    Nascimento, Luana Beatriz dos Santos; Moreira, Nattacha dos Santos; Leal-Costa, Marcos Vinícius; Costa, Sônia Soares; Tavares, Eliana Schwartz

    2015-10-01

    UV-B radiation can be stressful for plants and cause morphological and biochemical changes. Kalanchoe pinnata is a CAM leaf-succulent species distributed in hot and dry regions, and is rich in flavonoids, which are considered to be protective against UV-B radiation. This study aims to verify if K. pinnata has morphological or anatomical responses as a strategy in response to high UV-B levels. Kalanchoe pinnata plants of the same age were grown under white light (control) or white light plus supplemental UV-B radiation (5 h d(-1)). The plants were treated with the same photoperiod, photosynthetically active radiation, temperature and daily watering system. Fragments of the middle third of the leaf blade and petiole were dehydrated and then embedded in historesin and sectioned in a rotary microtome. Sections were stained with toluidine blue O and mounted in Entellan®. Microchemical analyses by optical microscopy were performed on fresh material with Sudan III, Sudan IV and phloroglucinol, and analysed using fluorescence microscopy. Supplemental UV-B radiation caused leaf curling and the formation of brown areas on the leaves. These brown areas developed into a protective tissue on the adaxial side of the leaf, but only in directly exposed regions. Anatomically, this protective tissue was similar to a wound-periderm, with outer layer cell walls impregnated with suberin and lignin. This is the first report of wound-periderm formation in leaves in response to UV-B radiation. This protective tissue could be important for the survival of the species in desert regions under high UV-B stress conditions. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  7. Plant responses to plant growth-promoting rhizobacteria

    NARCIS (Netherlands)

    Loon, L.C. van

    2007-01-01

    Non-pathogenic soilborne microorganisms can promote plant growth, as well as suppress diseases. Plant growth promotion is taken to result from improved nutrient acquisition or hormonal stimulation. Disease suppression can occur through microbial antagonism or induction of resistance in the plant.

  8. Isolation and characterization of a Vitis vinifera transcription factor, VvWRKY1, and its effect on responses to fungal pathogens in transgenic tobacco plants.

    Science.gov (United States)

    Marchive, Chloé; Mzid, Rim; Deluc, Laurent; Barrieu, François; Pirrello, Julien; Gauthier, Adrien; Corio-Costet, Marie-France; Regad, Farid; Cailleteau, Bernard; Hamdi, Saïd; Lauvergeat, Virginie

    2007-01-01

    Pathogen attack represents a major problem for viticulture and for agriculture in general. At present, the use of phytochemicals is more and more restrictive, and therefore it is becoming essential to control disease by having a thorough knowledge of resistance mechanisms. The present work focused on the trans-regulatory proteins potentially involved in the control of the plant defence response, the WRKY proteins. A full-length cDNA, designated VvWRKY1, was isolated from a grape berry library (Vitis vinifera L. cv. Cabernet Sauvignon). It encodes a polypeptide of 151 amino acids whose structure is characteristic of group IIc WRKY proteins. VvWRKY1 gene expression in grape is regulated in a developmental manner in berries and leaves and by various signal molecules involved in defence such as salicylic acid, ethylene, and hydrogen peroxide. Biochemical analysis indicates that VvWRKY1 specifically interacts with the W-box in various nucleotidic contexts. Functional analysis of VvWRKY1 was performed by overexpression in tobacco, and transgenic plants exhibited reduced susceptibility to various fungi but not to viruses. These results are consistent with a possible role for VvWRKY1 in grapevine defence against fungal pathogens.

  9. Plant Cell Adaptive Responses to Microgravity

    Science.gov (United States)

    Kordyum, Elizabeth; Kozeko, Liudmyla; Talalaev, Alexandr

    simulated microgravity and temperature elevation have different effects on the small HSP genes belonging to subfamilies with different subcellular localization: cytosol/nucleus - PsHSP17.1-CII and PsHSP18.1-CI, cloroplasts - PsHSP26.2-Cl, endoplasmatic reticulum - PsHSP22.7-ER and mitochondria - PsHSP22.9-M: unlike high temperature, clinorotation does not cause denaturation of cell proteins, that confirms the sHSP chaperone function. Dynamics of investigated gene expression in pea seedlings growing 5 days after seed germination under clinorotation was similar to that in the stationary control. Similar patterns in dynamics of sHSP gene expression in the stationary control and under clinorotation may be one of mechanisms providing plant adaptation to simulated microgravity. It is pointed that plant cell responses in microgravity and under clinorotation vary according to growth phase, physiological state, and taxonomic position of the object. At the same time, the responses have, to some degree, a similar character reflecting the changes in cell organelle functional load. Thus, next certain changes in the structure and function of plant cells may be considered as adaptive: 1) an increase in the unsaturated fatty acid content in the plasmalemma, 2) rearrangements of organelle ultrastructure and an increase in their functional load, 3) an increase in cortical F-actin under destabilization of tubulin microtubules, 4) the level of gene expression and synthesis of heat shock proteins, 5) alterations of the enzyme and antioxidant system activity. The dynamics of these patterns demonstrated that the adaptation occurs on the principle of self-regulating systems in the limits of physiological norm reaction. The very importance of changed expression of genes involved in different cellular processes, especially HSP genes, in cell adaptation to altered gravity is discussed.

  10. Testing for the induction of anti-herbivory defences in four Portuguese macroalgae by direct and water-borne cues of grazing amphipods

    Science.gov (United States)

    Yun, Hee Young; Cruz, Joana; Treitschke, Michaela; Wahl, Martin; Molis, Markus

    2007-09-01

    Herbivory is a key factor in regulating plant biomass, thereby driving ecosystem performance. Algae have developed multiple adaptations to cope with grazers, including morphological and chemical defences. In a series of experiments we investigated whether several species of macroalgae possess anti-herbivore defences and whether these could be regulated to demand, i.e. grazing events. The potential of direct grazing on defence induction was assessed for two brown ( Dictyopteris membranacea, Fucus vesiculosus) and two red seaweeds ( Gelidium sesquipedale, Sphaerococcus coronopifolius) from São Rafael and Ria Formosa, Portugal. Bioassays conducted with live algal pieces and agar-based food containing lipophilic algal extracts were used to detect changes in palatability after exposure to amphipod attacks (=treatment phase). Fucus vesiculosus was the only species significantly reducing palatability in response to direct amphipod-attacks. This pattern was observed in live F. vesiculosus pieces and agar-based food containing a lipophilic extract, suggesting that lipophilic compounds produced during the treatment phase were responsible for the repulsion of grazers. Water-borne cues of grazed F. vesiculosus as well as non-grazing amphipods also reduced palatability of neighbouring conspecifics. However, this effect was only observed in live tissues of F. vesiculosus. This study is the first to show that amphipods, like isopods, are capable to induce anti-herbivory defences in F. vesiculosus and that a seasonally variable effectiveness of chemical defences might serve as a dynamic control in alga-herbivore interactions.

  11. 4th International Conference in Software Engineering for Defence Applications

    CERN Document Server

    Sillitti, Alberto; Succi, Giancarlo; Messina, Angelo

    2016-01-01

    This book presents high-quality original contributions on new software engineering models, approaches, methods, and tools and their evaluation in the context of defence and security applications. In addition, important business and economic aspects are discussed, with a particular focus on cost/benefit analysis, new business models, organizational evolution, and business intelligence systems. The contents are based on presentations delivered at SEDA 2015, the 4th International Conference in Software Engineering for Defence Applications, which was held in Rome, Italy, in May 2015. This conference series represents a targeted response to the growing need for research that reports and debates the practical implications of software engineering within the defence environment and also for software performance evaluation in real settings through controlled experiments as well as case and field studies. The book will appeal to all with an interest in modeling, managing, and implementing defence-related software devel...

  12. Biochar and Ecosystem Restoration: Plant Ecophysiological Responses

    Science.gov (United States)

    Gale, N.; Halim, M. A.; Thomas, S. C.

    2017-12-01

    Charcoal is thought to facilitate rapid plant regeneration following fires by increasing the retention and availability of nutrients and water, increasing soil pH, and by sorbing toxic and inhibitory soil compounds - responses that have recently encouraged research on "biochar," or charcoal used as a soil amendment. Interest in biochar for use in the restoration of disturbed systems is growing; however, investigations of the effects of biochar on wild plants and trees are lacking. We present results from two experiments testing the influence of biochar on the growth and physiology of pioneers. In the first study, in a glasshouse, we examined the effects of maple biochar (10 and 20 t/ha) applied to a temperate managed forest soil on the ecophysiology of 13 herbaceous old-field species. In the second study, in field trials in Bangladesh (15 x 15 m plots), we examined the effects of acacia biochar (7.5 t/ha) on the growth of regenerating dipterocarp secondary forests. In both experiments, we measured changes in nutrient availability to help explain ecophysiological responses. Biochars enhanced the performance of early successional old-field pioneers: increasing aboveground biomass (37%), photosynthesis (17%), reproductive biomass (100%), and water use efficiency (44%), but with high species-specific variation that included negative responses. In tropical forests, biochars marginally improved the growth and recruitment of canopy dipterocarps and increased the photosynthetic performance and abundance of some, but not all, of the dominant understory species. In both experiments, growth enhancement was due to pulses of PO4-and K+ supplied by biochar in the short term; while null and negative responses were the result of nitrogen immobilization for species with high photosynthetic capacities. These results suggest that by providing a pulse of P and base cations, biochar can improve the restoration of disturbed landscapes by enhancing the physiological performance of

  13. Radiation protection in civil defence

    International Nuclear Information System (INIS)

    Ahlborn, K.

    The brochure contains the information given to the participants of an advanced training course in civil defence, on the subject of radiation protection. The course was held by teachers of Bundesverband fuer den Selbstschutz (BVS). (orig.) [de

  14. Physcomitrella patens activates reinforcement of the cell wall, programmed cell death and accumulation of evolutionary conserved defence signals, such as salicylic acid and 12-oxo-phytodienoic acid, but not jasmonic acid, upon Botrytis cinerea infection.

    Science.gov (United States)

    Ponce De León, Inés; Schmelz, Eric A; Gaggero, Carina; Castro, Alexandra; Álvarez, Alfonso; Montesano, Marcos

    2012-10-01

    The moss Physcomitrella patens is an evolutionarily basal model system suitable for the analysis of plant defence responses activated after pathogen assault. Upon infection with the necrotroph Botrytis cinerea, several defence mechanisms are induced in P. patens, including the fortification of the plant cell wall by the incorporation of phenolic compounds and the induced expression of related genes. Botrytis cinerea infection also activates the accumulation of reactive oxygen species and cell death with hallmarks of programmed cell death in moss tissues. Salicylic acid (SA) levels also increase after fungal infection, and treatment with SA enhances transcript accumulation of the defence gene phenylalanine ammonia-lyase (PAL) in P. patens colonies. The expression levels of the genes involved in 12-oxo-phytodienoic acid (OPDA) synthesis, including lipoxygenase (LOX) and allene oxide synthase (AOS), increase in P. patens gametophytes after pathogen assault, together with a rise in free linolenic acid and OPDA concentrations. However, jasmonic acid (JA) could not be detected in healthy or infected tissues of this plant. Our results suggest that, although conserved defence signals, such as SA and OPDA, are synthesized and are probably involved in the defence response of P. patens against B. cinerea infection, JA production appears to be missing. Interestingly, P. patens responds to OPDA and methyl jasmonate by reducing moss colony growth and rhizoid length, suggesting that jasmonate perception is present in mosses. Thus, P. patens can provide clues with regard to the evolution of different defence pathways in plants, including signalling and perception of OPDA and jasmonates in nonflowering and flowering plants. © 2012 THE AUTHORS. MOLECULAR PLANT PATHOLOGY © 2012 BSPP AND BLACKWELL PUBLISHING LTD.

  15. Costs and benefits of chemical defence in the Red Alga Bonnemaisonia hamifera.

    Directory of Open Access Journals (Sweden)

    Göran M Nylund

    Full Text Available A number of studies have shown that the production of chemical defences is costly in terrestrial vascular plants. However, these studies do not necessarily reflect the costs of defence production in macroalgae, due to structural and functional differences between vascular plants and macroalgae. Using a specific culturing technique, we experimentally manipulated the defence production in the red alga Bonnemaisonia hamifera to examine if the defence is costly in terms of growth. Furthermore, we tested if the defence provides fitness benefits by reducing harmful bacterial colonisation of the alga. Costly defences should provide benefits to the producer in order to be maintained in natural populations, but such benefits through protection against harmful bacterial colonisation have rarely been documented in macroalgae. We found that algae with experimentally impaired defence production, but with an externally controlled epibacterial load, grew significantly better than algae with normal defence production. We also found that undefended algae exposed to a natural epibacterial load experienced a substantial reduction in growth and a 6-fold increase in cell bleaching, compared to controls. Thus, this study provides experimental evidence that chemical defence production in macroalgae is costly, but that the cost is outweighed by fitness benefits provided through protection against harmful bacterial colonisation.

  16. Rosatom Corporation at the All-Russian civil defence training exercise

    International Nuclear Information System (INIS)

    Glukhikh, E.N.; Glazunov, A.V.; Tyurin, R.L.

    2012-01-01

    The 80th anniversary of civil defence in Russia was marked by the All-Russian civil defence exercise attended by representatives of federal executive authorities, regional and local executive authorities. During the exercise performance of the following activities was verified: introduction of increased preparedness mode for local air-defence emergency-response forces, activities of emergency-response and fire safety commissions, information collection and exchange during implementation of top-priority civil defence measures, etc. The paper describes the activities carried out during the exercise [ru

  17. Aerodynamic Test Facility Requirements for Defence R&D to 2000 and Beyond.

    Science.gov (United States)

    1982-09-01

    Defence Force. Following its review of science and technology, the Australian Science and Technology Council ( ASTEC ) reported I that the present pattern...Organisation (DSTO) within the Department of Defence. Accordingly, ASTEC recommended to the Prime Minister that the Department of Defence be asked to develop...DSTO2 as well as by ASTEC 1 . An additional reason for choosing aerodynamics for early consideration in response to ASTEC’s recommendation is that wind

  18. Disruption of the ammonium transporter AMT1.1 alters basal defences generating resistance against Pseudomonas syringae and Plectosphaerella cucumerina

    Directory of Open Access Journals (Sweden)

    Victoria ePastor

    2014-05-01

    Full Text Available Disruption of the high-affinity nitrate transporter NRT2.1 activates the priming defence against Pseudomonas syringae, resulting in enhanced resistance. In this study, it is demonstrated that the high-affinity ammonium transporter AMT1.1 is a negative regulator of Arabidopsis defence responses. The T-DNA knockout mutant amt1.1 displays enhanced resistance against Plectosphaerella cucumerina and reduced susceptibility to P. syringae. The impairment of AMT1.1 induces significant metabolic changes in the absence of challenge, suggesting that amt1.1 retains constitutive defence responses. Interestingly, amt1.1 combats pathogens differently depending on the lifestyle of the pathogen. In addition, N starvation enhances the susceptibility of wild type plants and the mutant amt1.1 to P. syringae whereas it has no effect on P. cucumerina resistance. The metabolic changes of amt1.1 against P. syringae are subtler and are restricted to the phenylpropanoid pathway, which correlates with its reduced susceptibility. By contrast, the amt1.1 mutant responds by activating higher levels of camalexin and callose against P. cucumerina. In addition, amt1.1 shows altered levels of aliphatic and indolic glucosinolates and other Trp-related compounds following infection by the necrotroph. These observations indicate that AMT1.1 may play additional roles that affect N uptake and plant immune responses.

  19. Plant responses to variable timing of aboveground clipping and belowground herbivory depend on plant age

    NARCIS (Netherlands)

    Wang, Minggang; Bezemer, T. Martijn; van der Putten, W.H.; Brinkman, Pella; Biere, Arjen

    2017-01-01

    Aims Plants use different types of responses such as tolerance and induced defense to mitigate the effects of herbivores. The direction and magnitude of both these plant responses can vary with plant age. However, most studies have focused on aboveground herbivory, whereas important feeding occurs

  20. Physiological and Biochemical Responses of Saltmarsh Plant Spartina alterniflora to Long-term Wave Exposure

    Science.gov (United States)

    Zhou, W.

    2017-12-01

    In recent years, ecosystem-based flood defence, i.e., eco-shoreline or living shoreline, that is more sustainable and cost-effective than conventional coastal engineering structures has been brought into large-scale practice. Numerous laboratory experiments have been performed to explore the wave-attenuation effects of saltmarsh plants that are widely used in eco-shoreline, and yet no study has ever been conducted on the physiological and biochemical responses of saltmarsh plants to long-term wave exposure, presumably due to the constraint that traditional wave generator fails to provide long-term stable wave conditions necessary for physiological experiments. In this study, a long-term shallow water wave environment simulator using crank-yoke mechanism was built in the laboratory to address this gap. Experiments using the wave simulator were conducted for 8 weeks in a greenhouse and the temperature was maintained at 24-30°C. 5‰ artificial sea water was filled in the test tank, and the water was changed every week. After being acclimatized, nine S. alterniflora individual plants (initial height 30 cm) were planted in each of the three streamlined cuboid containers (12cm×12cm×20cm), which were partially submerged in a test tank, and undertook horizontal sinusoidal motion imposed by the crank-yoke mechanism to mimic plants exposed to shallow water waves. The substrate filled in the containers were soils collected from the Yellow River Delta, so were the S. alterniflora plants. A realistic stem density of 400 stems/m2 was tested, which corresponded to a grid spacing of 5.0 cm. Shallow water waves with six wave heights (H: 0.041, 0.055, 0.069, 0.033, 0.044 and 0.056m), one plants submerged depth (0.1m) and two wave periods (2s and 3s) were simulated in the experiments. A no wave condition was also tested as control. Key physiological and biochemical parameters, such as stem length, peroxidase activity, catalase, superoxide dismutase, ascorbate peroxidase, etc

  1. In Defence of Pashukanism

    Directory of Open Access Journals (Sweden)

    R Koen

    2011-07-01

    Full Text Available This essay presents an extended defence of the general theory of law formulated by the Bolshevik jurist, Evgeny Pashukanis, and published in his Law and Marxism: A General Theory in 1924. The general theory is a theory of the legal form. Although Pashukanis did not name his theory, it has become known as the commodity form theory of law because of its theorising the legal form as a homologue of the commodity form. However, despite having weighty Marxist and revolutionary Bolshevik credentials, the general theory has been subjected to sustained attack, especially from new left and neo-Marxist circles. This essay identifies and explicates six major objections to Pashukanism from its left critics. These are that the general theory is too abstract to comprehend the reality of legal relations; that it is infused with economic reductionism; that it derives the legal form wrongly from commodity exchange; that it classifies the legal form incorrectly as an attribute of capitalism only; that it lacks the generality required of a general theory of law; and that it is imbricated in the growth of anarchism and Stalinism. Following a brief exegetical exercise, the bulk of the essay is devoted to demonstrating in detail that each of the six objections to the general theory is without merit, and that none makes any serious incursion into its integrity as a theory of the legal form. The central submission of the essay is that the Pashukanist general theory of law is rooted in the first principles of classical Marxism and hence may lay claim legitimately to being the Marxist theory of law.

  2. Leaf biochemical responses and fruit oil quality parameters in olive plants subjected to airborne metal pollution.

    Science.gov (United States)

    Fourati, Radhia; Scopa, Antonio; Ben Ahmed, Chedlia; Ben Abdallah, Ferjani; Terzano, Roberto; Gattullo, Concetta Eliana; Allegretta, Ignazio; Galgano, Fernanda; Caruso, Marisa Carmela; Sofo, Adriano

    2017-02-01

    This study was carried out in two olive orchards (Olea europaea L., cv. Chemlali) located in a polluted area near a fertilizers factory and in a control unpolluted site, managed with similar cultivation techniques. The aim was to investigate the physiological and biochemical responses of polluted plants (PP), exposed to atmospheric metal contamination (Cd, Cu, Fe, Mn, Ni and Pb) as compared to control plants (CP). Leaves, roots and fruits of PP showed a depression of their non-enzymatic and enzymatic antioxidant defences and a disruption of their hormonal homeostasis. The anomalous physiological status of PP was also demonstrated by the lower values of pigments in leaves and fruits, as compared to CP. Atmospheric metals negatively affected olive oil chemical and sensory quality. However, despite metal deposition on fruit surfaces, the accumulation of potentially toxic metals in olive oil was negligible. Considering that olive oil is an important food product worldwide and that many productive olive orchards are exposed to several sources of pollution, this work could contribute to clarify the effects of atmospheric metal pollution on olive oil quality and its potential toxicity for humans. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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.

  4. Transcriptional profiling approaches to understanding how plants regulate growth and defence: a case study illustrated by analysis of the role of vitamin C.

    Science.gov (United States)

    Foyer, Christine H; Kiddle, Guy; Verrier, Paul

    2007-01-01

    In this chapter, basic technical aspects concerning the design of DNA microarray experiments are discussed including sample preparation, hybridisation conditions and statistical significance of the acquired data are detailed. Given that microarrays are perhaps the most used tool in plant systems biology there is much experience in the pitfalls in using them. Herein important considerations are presented for both the experimental biologists and data analyst in order to maximise the utility of these resources. Finally a case study using the analysis of vitamin C deficient plants is presented to illustrate the power of this approach in enhancing comprehension of important and complex biological functions.

  5. Testing phenotypic trade-offs in the chemical defence strategy of Scots pine under growth-limiting field conditions.

    Science.gov (United States)

    Villari, Caterina; Faccoli, Massimo; Battisti, Andrea; Bonello, Pierluigi; Marini, Lorenzo

    2014-09-01

    Plants protect themselves from pathogens and herbivores through fine-tuned resource allocation, including trade-offs among resource investments to support constitutive and inducible defences. However, empirical research, especially concerning conifers growing under natural conditions, is still scarce. We investigated the complexity of constitutive and induced defences in a natural Scots pine (Pinus sylvestris L.) stand under growth-limiting conditions typical of alpine environments. Phenotypic trade-offs at three hierarchical levels were tested by investigating the behaviour of phenolic compounds and terpenoids of outer bark and phloem. We tested resource-derived phenotypic correlations between (i) constitutive and inducible defences vs tree ring growth, (ii) different constitutive defence metabolites and (iii) constitutive concentration and inducible variation of individual metabolites. Tree ring growth was positively correlated only with constitutive concentration of total terpenoids, and no overall phenotypic trade-offs between different constitutive defensive metabolites were found. At the lowest hierarchical level tested, i.e., at the level of relationship between constitutive and inducible variation of individual metabolites, we found that different compounds displayed different behaviours; we identified five different defensive metabolite response types, based on direction and strength of the response, regardless of tree age and growth rate. Therefore, under growth-limiting field conditions, Scots pine appears to utilize varied and complex outer bark and phloem defence chemistry, in which only part of the constitutive specialized metabolism is influenced by tree growth, and individual components do not appear to be expressed in a mutually exclusive manner in either constitutive or inducible metabolism. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. The long-term resistance mechanisms, critical irrigation threshold and relief capacity shown by Eugenia myrtifolia plants in response to saline reclaimed water

    DEFF Research Database (Denmark)

    Acosta-Motos, José Ramón; Hernández, José Antonio; Álvarez, Sara

    2017-01-01

    water potential, the relative water content of leaves, leaf stomatal conductance, the leaf photosynthetic rate, water-use efficiency and accumulated evapotranspiration in order to limit water loss; and 4) changes in the antioxidant defence mechanisms. These different responses induced oxidative stress...... to different electric conductivities of the treatments. Based on these premises, we studied the long-term effect of three reclaimed water treatments with different saline concentrations on Eugenia myrtifolia plants. We also looked at the ability of these plants to recover when no drainage was applied. The RW...... with the highest electric conductivity (RW3, EC = 6.96 dS m(-1)) provoked a number of responses to salinity in these plants, including: 1) accumulation and extrusion of phytotoxic ions in roots; 2) a decrease in the shoot/root ratio, leaf area, number of leaves; 3) a decrease in root hydraulic conductivity, leaf...

  7. Agroecology: Implications for plant response to climate change

    Science.gov (United States)

    Agricultural ecosystems (agroecosystems) represent the balance between the physiological responses of plants and plant canopies and the energy exchanges. Rising temperature and increasing CO2 coupled with an increase in variability of precipitation will create a complex set of interactions on plant ...

  8. Agrobacterium tumefaciens responses to plant-derived signaling molecules

    Science.gov (United States)

    Subramoni, Sujatha; Nathoo, Naeem; Klimov, Eugene; Yuan, Ze-Chun

    2014-01-01

    As a special phytopathogen, Agrobacterium tumefaciens infects a wide range of plant hosts and causes plant tumors also known as crown galls. The complexity of Agrobacterium–plant interaction has been studied for several decades. Agrobacterium pathogenicity is largely attributed to its evolved capabilities of precise recognition and response to plant-derived chemical signals. Agrobacterium perceives plant-derived signals to activate its virulence genes, which are responsible for transferring and integrating its Transferred DNA (T-DNA) from its Tumor-inducing (Ti) plasmid into the plant nucleus. The expression of T-DNA in plant hosts leads to the production of a large amount of indole-3-acetic acid (IAA), cytokinin (CK), and opines. IAA and CK stimulate plant growth, resulting in tumor formation. Agrobacterium utilizes opines as nutrient sources as well as signals in order to activate its quorum sensing (QS) to further promote virulence and opine metabolism. Intriguingly, Agrobacterium also recognizes plant-derived signals including γ-amino butyric acid and salicylic acid (SA) to activate quorum quenching that reduces the level of QS signals, thereby avoiding the elicitation of plant defense and preserving energy. In addition, Agrobacterium hijacks plant-derived signals including SA, IAA, and ethylene to down-regulate its virulence genes located on the Ti plasmid. Moreover, certain metabolites from corn (Zea mays) also inhibit the expression of Agrobacterium virulence genes. Here we outline the responses of Agrobacterium to major plant-derived signals that impact Agrobacterium–plant interactions. PMID:25071805

  9. Agrobacterium tumefaciens responses to plant-derived signaling molecules

    Directory of Open Access Journals (Sweden)

    Sujatha eSubramoni

    2014-07-01

    Full Text Available As a special phytopathogen, Agrobacterium tumefaciens infects a wide range of plant hosts and causes plant tumors also known as crown galls. The complexity of Agrobacterium-plant interaction has been studied for several decades. Agrobacterium pathogenicity is largely attributed to its evolved capabilities of precise recognition and response to plant-derived chemical signals. Agrobacterium perceives plant-derived signals to activate its virulence genes, which are responsible for transferring and integrating its T-DNA (Transferred DNA from its Tumour-inducing (Ti plasmid into the plant nucleus. The expression of T-DNA in plant hosts leads to the production of a large amount of indole-3-acetic acid (IAA, cytokinin (CK and opines. IAA and CK stimulate plant growth, resulting in tumor formation. Agrobacterium utilizes opines as nutrient sources as well as signals in order to activate its quorum sensing (QS to further promote virulence and opine metabolism. Intriguingly, Agrobacterium also recognizes plant-derived signals including -amino butyric acid (GABA and salicylic acid (SA to activate quorum quenching that reduces the level of QS signals, thereby avoiding the elicitation of plant defense and preserving energy. In addition, Agrobacterium hijacks plant-derived signals including SA, IAA, and ethylene (ET to down-regulate its virulence genes located on the Ti plasmid. Moreover, certain metabolites from corn (Zea mays also inhibit the expression of Agrobacterium virulence genes. Here we outline the responses of Agrobacterium to major plant-derived signals that impact Agrobacterium-plant interactions.

  10. Role of the Regulatory Body in Implementing Defence in Depth in Nuclear Installations - Regulatory Oversight in Egypt

    Energy Technology Data Exchange (ETDEWEB)

    El-Sheikh, B. M., E-mail: badawymel@yahoo.com [Egyptian Nuclear and Radiological Regulatory Authority Cairo (Egypt)

    2014-10-15

    The fundamental objective of all nuclear safety regulatory bodies is to ensure that nuclear facilities are operated at all times in an acceptably safe manner including the safe conduct of decommissioning activities. Defence in depth is recognized as one of the fundamental safety principles that underlie the safety of nuclear power plants. Defence in depth is implemented to provide a graded protection against a wide variety of transients, incidents and accidents, including equipment failures and human errors within nuclear power plants and events initiated outside plants. The Regulator Body plays an important role in implementing defence in depth in nuclear installations in the context of a clear allocation of responsibilities with an operating organization. This role starting with setting safety objectives and by its own independent review and technical assessment of the safety justifications provided by the operating organization in addition to safety culture investigating within relevant organizations. This paper briefly reviews this role in normal operation and post accidents, and its effects on overall nuclear safety in nuclear installations with reference to Egyptian regulatory oversight. (author)

  11. Induction of host defences by Rhizobium during ineffective nodulation of pea (Pisum sativum L.) carrying symbiotically defective mutations sym40 (PsEFD), sym33 (PsIPD3/PsCYCLOPS) and sym42.

    Science.gov (United States)

    Ivanova, Kira A; Tsyganova, Anna V; Brewin, Nicholas J; Tikhonovich, Igor A; Tsyganov, Viktor E

    2015-11-01

    Rhizobia are able to establish a beneficial interaction with legumes by forming a new organ, called the symbiotic root nodule, which is a unique ecological niche for rhizobial nitrogen fixation. Rhizobial infection has many similarities with pathogenic infection and induction of defence responses accompanies both interactions, but defence responses are induced to a lesser extent during rhizobial infection. However, strong defence responses may result from incompatible interactions between legumes and rhizobia due to a mutation in either macro- or microsymbiont. The aim of this research was to analyse different plant defence reactions in response to Rhizobium infection for several pea (Pisum sativum) mutants that result in ineffective symbiosis. Pea mutants were examined by histochemical and immunocytochemical analyses, light, fluorescence and transmission electron microscopy and quantitative real-time PCR gene expression analysis. It was observed that mutations in pea symbiotic genes sym33 (PsIPD3/PsCYCLOPS encoding a transcriptional factor) and sym40 (PsEFD encoding a putative negative regulator of the cytokinin response) led to suberin depositions in ineffective nodules, and in the sym42 there were callose depositions in infection thread (IT) and host cell walls. The increase in deposition of unesterified pectin in IT walls was observed for mutants in the sym33 and sym42; for mutant in the sym42, unesterified pectin was also found around degrading bacteroids. In mutants in the genes sym33 and sym40, an increase in the expression level of a gene encoding peroxidase was observed. In the genes sym40 and sym42, an increase in the expression levels of genes encoding a marker of hypersensitive reaction and PR10 protein was demonstrated. Thus, a range of plant defence responses like suberisation, callose and unesterified pectin deposition as well as activation of defence genes can be triggered by different pea single mutations that cause perception of an otherwise

  12. Modelling joint air defence doctrinal issues with a LinkZA-based integration of two C2 simulators – a case study

    CSIR Research Space (South Africa)

    Nel, JJ

    2007-07-01

    Full Text Available This paper describes the integration between two command and control simulators in order to clarify doctrinal issues surrounding Joint Air Defence using as example the uncertainty of roles and responsibilities between the Air Defence Cell...

  13. Evolutionary responses of native plant species to invasive plants: a review.

    Science.gov (United States)

    Oduor, Ayub M O

    2013-12-01

    Strong competition from invasive plant species often leads to declines in abundances and may, in certain cases, cause localized extinctions of native plant species. Nevertheless, studies have shown that certain populations of native plant species can co-exist with invasive plant species,suggesting the possibility of adaptive evolutionary responses of those populations to the invasive plants. Empirical inference of evolutionary responses of the native plant species to invasive plants has involved experiments comparing two conspecific groups of native plants for differences in expression of growth/reproductive traits: populations that have experienced competition from the invasive plant species (i.e. experienced natives) versus populations with no known history of interactions with the invasive plant species (i.e. naıve natives). Here, I employ a meta-analysis to obtain a general pattern of inferred evolutionary responses of native plant species from 53 such studies. In general, the experienced natives had significantly higher growth/reproductive performances than naıve natives, when grown with or without competition from invasive plants.While the current results indicate that certain populations of native plant species could potentially adapt evolutionarily to invasive plant species, the ecological and evolutionary mechanisms that probably underlie such evolutionary responses remain unexplored and should be the focus of future studies.

  14. Emergency response training with the BNL plant analyzer

    International Nuclear Information System (INIS)

    Cheng, H.S.; Guppy, J.G.; Mallen, A.N.; Wulff, W.

    1987-01-01

    Presented is the experience in the use of the BNL Plant Analyzer for NRC emergency response training to simulated accidents in a BWR. The unique features of the BNL Plant Analyzer that are important for the emergency response training are summarized. A closed-loop simulation of all the key systems of a power plant in question was found essential to the realism of the emergency drills conducted at NRC. The faster than real-time simulation speeds afforded by the BNL Plant Analyzer have demonstrated its usefulness for the timely conduct of the emergency response training

  15. Physiological response of soybean genotypes to plant density

    NARCIS (Netherlands)

    Gan, Y; Stulen, [No Value; van Keulen, H; Kuiper, PJC

    2002-01-01

    Response of soybean (Glycine max (L.) Merr.) to plant density has occupied a segment of agronomic research for most of the century. Genotype differences have been noted especially in response to planting date, lodging problems and water limitation. There is limited information on the physiological

  16. Responses of potatoes plants inoculated with arbuscular ...

    African Journals Online (AJOL)

    A pot experiment was set to examine the impact of the foliar litter (Hardwickia binata and Azadirachta indica) and an arbuscular mycorrhizal (AM) fungus on the development of two varieties of potato plants (Aida, Atlas). Three litter doses (0, 25 and 50 g) were applied to the pots after bedding plantlets. The plants were ...

  17. Ecophysiological response to seasonal variations in water availability in the arborescent, endemic plant Vellozia gigantea.

    Science.gov (United States)

    Morales, Melanie; Garcia, Queila S; Munné-Bosch, Sergi

    2015-03-01

    The physiological response of plants growing in their natural habitat is strongly determined by seasonal variations in environmental conditions and the interaction of abiotic and biotic stresses. Here, leaf water and nutrient contents, changes in cellular redox state and endogenous levels of stress-related phytohormones (abscisic acid (ABA), salicylic acid and jasmonates) were examined during the rainy and dry season in Vellozia gigantea, an endemic species growing at high elevations in the rupestrian fields of the Espinhaço Range in Brazil. Enhanced stomatal closure and increased ABA levels during the dry season were associated with an efficient control of leaf water content. Moreover, reductions in 12-oxo-phytodienoic acid (OPDA) levels during the dry season were observed, while levels of other jasmonates, such as jasmonic acid and jasmonoyl-isoleucine, were not affected. Changes in ABA and OPDA levels correlated with endogenous concentrations of iron and silicon, hydrogen peroxide, and vitamin E, thus indicating complex interactions between water and nutrient contents, changes in cellular redox state and endogenous hormone concentrations. Results also suggested crosstalk between activation of mechanisms for drought stress tolerance (as mediated by ABA) and biotic stress resistance (mediated by jasmonates), in which vitamin E levels may serve as a control point. It is concluded that, aside from a tight ABA-associated regulation of stomatal closure during the dry season, crosstalk between activation of abiotic and biotic defences, and nutrient accumulation in leaves may be important modulators of plant stress responses in plants growing in their natural habitat. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Interaction between the moss Physcomitrella patens and Phytophthora: a novel pathosystem for live-cell imaging of subcellular defence.

    Science.gov (United States)

    Overdijk, Elysa J R; DE Keijzer, Jeroen; DE Groot, Deborah; Schoina, Charikleia; Bouwmeester, Klaas; Ketelaar, Tijs; Govers, Francine

    2016-08-01

    Live-cell imaging of plant-pathogen interactions is often hampered by the tissue complexity and multicell layered nature of the host. Here, we established a novel pathosystem with the moss Physcomitrella patens as host for Phytophthora. The tip-growing protonema cells of this moss are ideal for visualizing interactions with the pathogen over time using high-resolution microscopy. We tested four Phytophthora species for their ability to infect P. patens and showed that P. sojae and P. palmivora were only rarely capable to infect P. patens. In contrast, P. infestans and P. capsici frequently and successfully penetrated moss protonemal cells, showed intracellular hyphal growth and formed sporangia. Next to these successful invasions, many penetration attempts failed. Here the pathogen was blocked by a barrier of cell wall material deposited in papilla-like structures, a defence response that is common in higher plants. Another common response is the upregulation of defence-related genes upon infection and also in moss we observed this upregulation in tissues infected with Phytophthora. For more advanced analyses of the novel pathosystem we developed a special set-up that allowed live-cell imaging of subcellular defence processes by high-resolution microscopy. With this set-up, we revealed that Phytophthora infection of moss induces repositioning of the nucleus, accumulation of cytoplasm and rearrangement of the actin cytoskeleton, but not of microtubules. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

  19. Priming of antiherbivore defensive responses in plants

    Institute of Scientific and Technical Information of China (English)

    Jinwon Kim; Gary W.Felton

    2013-01-01

    Defense priming is defined as increased readiness of defense induction.A growing body of literature indicates that plants (or intact parts of a plant) are primed in anticipation of impending environmental stresses,both biotic and abiotic,and upon the following stimulus,induce defenses more quickly and strongly.For instance,some plants previously exposed to herbivore-inducible plant volatiles (HIPVs) from neighboring plants under herbivore attack show faster or stronger defense activation and enhanced insect resistance when challenged with secondary insect feeding.Research on priming of antiherbivore defense has been limited to the HIPV-mediated mechanism until recently,but significant advances were made in the past three years,including non-HIPV-mediated defense priming,epigenetic modifications as the molecular mechanism of priming,and others.It is timely to consider the advances in research on defense priming in the plantinsect interactions.

  20. Nuclear power reactors: reactor safety and military and civil defence

    International Nuclear Information System (INIS)

    Hvinden, T.

    1976-01-01

    The formation of fission products and plutonium in reactors is briefly described, followed by a short general discussion of reactor safety. The interaction of reactor safety and radioactive release considerations with military and civil defence is thereafter discussed. Reactors and other nuclear plants are factors which must be taken into account in the defence of the district around the site, and as potential targets of both conventional and guerilla attacks and sabotage, requiring special defence. The radiological hazards arising from serious damage to a power reactor by conventional weapons are briefly discussed, and the benefits of underground siting evaluated. Finally the author discusses the significance of the IAEA safeguards work as a preventive factor. (JIW)

  1. Plant response to biotic stress: Is there a common epigenetic response during plant-pathogenic and symbiotic interactions?

    Science.gov (United States)

    Zogli, Prince; Libault, Marc

    2017-10-01

    Plants constantly interact with pathogenic and symbiotic microorganisms. Recent studies have revealed several regulatory mechanisms controlling these interactions. Among them, the plant defense system is activated not only in response to pathogenic, but also in response to symbiotic microbes. Interestingly, shortly after symbiotic microbial recognition, the plant defense system is suppressed to promote plant infection by symbionts. Research studies have demonstrated the influence of the plant epigenome in modulating both pathogenic and symbiotic plant-microbe interactions, thereby influencing plant survival, adaptation and evolution of the plant response to microbial infections. It is however unclear if plant pathogenic and symbiotic responses share similar epigenomic profiles or if epigenomic changes differentially regulate plant-microbe symbiosis and pathogenesis. In this mini-review, we provide an update of the current knowledge of epigenomic control on plant immune responses and symbiosis, with a special attention being paid to knowledge gap and potential strategies to fill-in the missing links. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Silencing of acidic pathogenesis-related PR-1 genes increases extracellular beta-(1 -> 3)-glucanase activity at the onset of tobacco defence reactions

    DEFF Research Database (Denmark)

    Riviere, M.P.; Marais, A.; Ponchet, M.

    2008-01-01

    silenced. Plants lacking extracellular PR-1s were more susceptible than wild-type plants to the oomycete Phytophthora parasitica but displayed unaffected systemic acquired resistance and developmental resistance to this pathogen. Treatment with salicylic acid up-regulates the PR-1g gene, encoding a basic...... protein of the PR-1 family, in PR-1-deficient tobacco, indicating that PR-1 expression may repress that of PR-1g. This shows that acidic PR-1s are dispensable for expression of salicylic acid-dependent acquired resistances against P. parasitica and may reveal a functional overlap in tobacco defence......The class 1 pathogenesis-related (PR) proteins are thought to be involved in plant defence responses, but their molecular functions are unknown. The function of PR-1 was investigated in tobacco by generating stable PR-1a-silenced lines in which other acidic PR-1 genes (PR-1b and PR-1c) were...

  3. Perception of low red:far-red ratio compromises both salicylic acid- and jasmonic acid-dependent pathogen defences in Arabidopsis.

    Science.gov (United States)

    de Wit, Mieke; Spoel, Steven H; Sanchez-Perez, Gabino F; Gommers, Charlotte M M; Pieterse, Corné M J; Voesenek, Laurentius A C J; Pierik, Ronald

    2013-07-01

    In dense stands of plants, such as agricultural monocultures, plants are exposed simultaneously to competition for light and other stresses such as pathogen infection. Here, we show that both salicylic acid (SA)-dependent and jasmonic acid (JA)-dependent disease resistance is inhibited by a simultaneously reduced red:far-red light ratio (R:FR), the early warning signal for plant competition. Conversely, SA- and JA-dependent induced defences did not affect shade-avoidance responses to low R:FR. Reduced pathogen resistance by low R:FR was accompanied by a strong reduction in the regulation of JA- and SA-responsive genes. The severe inhibition of SA-responsive transcription in low R:FR appeared to be brought about by the repression of SA-inducible kinases. Phosphorylation of the SA-responsive transcription co-activator NPR1, which is required for full induction of SA-responsive transcription, was indeed reduced and may thus play a role in the suppression of SA-mediated defences by low R:FR-mediated phytochrome inactivation. Our results indicate that foraging for light through the shade-avoidance response is prioritised over plant immune responses when plants are simultaneously challenged with competition and pathogen attack. © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

  4. Conversion policy principles of defence factory

    International Nuclear Information System (INIS)

    Fedik, I.I.; Deniskin, V.P.; Stepanov, V.S.

    1997-01-01

    1.Research Production Association 'LUCH' (RPA 'LUCH') have worked at atomic industry for 51 years. Now it is one of the leading scientific production centers of Russia Ministry of Atomic Energy. Not long ago it was a complex of Scientific Research Institute, experimental plant and Obyedenennaya Expedicia at the Semipalatinsk test site (now it is the Institute of Atomic Energy NNC RK). Basic directions of the complex activity are defence tasks. These tasks are to develop structure and technology of producing fuel assemblies for NRE (nuclear rocket engine) reactors. Also the tasks include testing the fuel assemblies at IWG-1, RWD and RA reactors. Also the tasks include structure and technology development, production and testing electric generating channels for nuclear thermal emission converters of nuclear energy into electric one (space board power engineering), power metal optics for powerful lasers, high temperature gas reactors. 2.Main directions of RPA 'LUCH' conversion were determined on the basis of possibilities for developing main achievements in defence technology directions.These directions are high temperature materials and constructions (carbides, refractory metals, measurements, optics, uranium compound, beryllium, molybdenum) 3.At present at RPA 'LUCH' there have been created experimental and industrial productions making temperature sensors for Atomic Electric Power Stations (AEPS). Also these manufactures release commercial products. They produce technological equipment of carbide-silicon for electronic industry as well as parts or X-ray tubes, vermiculite parts for cable driving of AEP stations (high temperature, fireproof ones) of thermal and electrical accumulators. Thus, a scientific-production center is being created. Core of it is a scientific engineers group and development directions, generated from orders of defence department, as well as new foreign technologies (along with investments).The example of the said above can be development of a

  5. Experience with RTD response time testing in nuclear power plants

    International Nuclear Information System (INIS)

    Hashemian, H.M.; Kerlin, T.W.

    1985-01-01

    The reactor coolant temperatures in pressurized water reactors are measured with platinum resistance temperature detectors (RTDs). The information furnished by these RTDs is used for plant protection as well as control. As a part of the plant protection system, the RTDs must respond to temperature changes in a timely fashion. The RTD response time requirements are different for the various plant types. These requirements are specified in the plant technical specifications in terms of an RTd time constant. The current time constant requirements for nuclear plant RTDs varies from 0.5 seconds to 13.0 seconds depending on the type of the plant. Therefore, different types of RTDs are used in different plants to achieve the required time constants. In addition, in-situ response time tests are periodically performed on protective system RTDs to ensure that the in-service time constants are within acceptable limits as the plant is operating. The periodic testing is important because response time degradation may occur while the RTD ages in the process. Recent response time tests in operating plants revealed unacceptable time constants for several protection system RTDs. As a result, these plants had to be shut down to resolve the problem which in one case was due to improper installation and in another case was because of degradation of a thermal compound used in the thermowell

  6. Guidelines for nuclear plant response to an earthquake

    International Nuclear Information System (INIS)

    1989-12-01

    Guidelines have been developed to assist nuclear plant personnel in the preparation of earthquake response procedures for nuclear power plants. The objectives of the earthquake response procedures are to determine (1) the immediate effects of an earthquake on the physical condition of the nuclear power plant, (2) if shutdown of the plant is appropriate based on the observed damage to the plant or because the OBE has been exceeded, and (3) the readiness of the plant to resume operation following shutdown due to an earthquake. Readiness of a nuclear power plant to restart is determined on the basis of visual inspections of nuclear plant equipment and structures, and the successful completion of surveillance tests which demonstrate that the limiting conditions for operation as defined in the plant Technical Specifications are met. The guidelines are based on information obtained from a review of earthquake response procedures from numerous US and foreign nuclear power plants, interviews with nuclear plant operations personnel, and a review of reports of damage to industrial equipment and structures in actual earthquakes. 7 refs., 4 figs., 4 tabs

  7. Role of Arginine decarboxylase (ADC) in Arabidopsis thaliana defence against the pathogenic bacterium Pseudomonas viridiflava.

    Science.gov (United States)

    Rossi, F R; Marina, M; Pieckenstain, F L

    2015-07-01

    Polyamine biosynthesis starts with putrescine production through the decarboxylation of arginine or ornithine. In Arabidopsis thaliana, putrescine is synthesised exclusively by arginine decarboxylase (ADC), which exists as two isoforms (ADC1 and 2) that are differentially regulated by abiotic stimuli, but their role in defence against pathogens has not been studied in depth. This work analysed the participation of ADC in Arabidopsis defence against Pseudomonas viridiflava. ADC activity and expression, polyamine levels and bacterial resistance were analysed in null mutants of each ADC isoform. In non-infected wild-type (WT) plants, ADC2 expression was much higher than ADC1. Analysis of adc mutants demonstrated that ADC2 contributes to a much higher extent than ADC1 to basal ADC activity and putrescine biosynthesis. In addition, adc2 mutants showed increased basal expression of salicylic acid- and jasmonic acid-dependent PR genes. Bacterial infection induced putrescine accumulation and ADC1 expression in WT plants, but pathogen-induced putrescine accumulation was blocked in adc1 mutants. Results suggest a specific participation of ADC1 in defence, although basal resistance was not decreased by dysfunction of either of the two ADC genes. In addition, and as opposed to WT plants, bacterial infection increased ADC2 expression and ADC activity in adc1 mutants, which could counterbalance the lack of ADC1. Results demonstrate a major contribution of ADC2 to total ADC activity and the specific induction of ADC1 in response to infection. A certain degree of functional redundancy between the two isoforms in relation to their contribution to basal resistance is also evident. © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.

  8. On-line acquisition of plant related and environmental parameters (plant monitoring) in gerbera: determining plant responses

    NARCIS (Netherlands)

    Baas, R.; Slootweg, G.

    2004-01-01

    For on-line plant monitoring equipment to be functional in commercial glasshouse horticulture, relations between sensor readings and plant responses on both the short (days) and long term (weeks) are required. For this reason, systems were installed to monitor rockwool grown gerbera plants on a

  9. Operational Analysis on Torpedo Defence

    NARCIS (Netherlands)

    Grootendordt, H.J.; Benders, F.P.A.; Fitski, H.J.; Veldhoven, E.R. van

    2008-01-01

    Surface vessels and submarines must be able to defend themselves against a torpedo attack. Self-defence can be approached as a modular concept. The first module involves 'Detection, Classification and Localisation (DCL)'. DCL triggers the second module: the 'evaluator'. This module starts the last

  10. Fungal Production and Manipulation of Plant Hormones.

    Science.gov (United States)

    Fonseca, Sandra; Radhakrishnan, Dhanya; Prasad, Kalika; Chini, Andrea

    2018-01-01

    Living organisms are part of a highly interconnected web of interactions, characterised by species nurturing, competing, parasitizing and preying on one another. Plants have evolved cooperative as well as defensive strategies to interact with neighbour organisms. Among these, the plant-fungus associations are very diverse, ranging from pathogenic to mutualistic. Our current knowledge of plant-fungus interactions suggests a sophisticated coevolution to ensure dynamic plant responses to evolving fungal mutualistic/pathogenic strategies. The plant-fungus communication relies on a rich chemical language. To manipulate the plant defence mechanisms, fungi produce and secrete several classes of biomolecules, whose modeof- action is largely unknown. Upon perception of the fungi, plants produce phytohormones and a battery of secondary metabolites that serve as defence mechanism against invaders or to promote mutualistic associations. These mutualistic chemical signals can be co-opted by pathogenic fungi for their own benefit. Among the plant molecules regulating plant-fungus interaction, phytohormones play a critical role since they modulate various aspects of plant development, defences and stress responses. Intriguingly, fungi can also produce phytohormones, although the actual role of fungalproduced phytohormones in plant-fungus interactions is poorly understood. Here, we discuss the recent advances in fungal production of phytohormone, their putative role as endogenous fungal signals and how fungi manipulate plant hormone balance to their benefits. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  11. Regulation of abiotic and biotic stress responses by plant hormones

    DEFF Research Database (Denmark)

    Grosskinsky, Dominik Kilian; van der Graaff, Eric; Roitsch, Thomas Georg

    2016-01-01

    Plant hormones (phytohormones) are signal molecules produced within the plant, and occur in very low concentrations. In the present chapter, the current knowledge on the regulation of biotic and biotic stress responses by plant hormones is summarized with special focus on the novel insights...... into the complex hormonal crosstalk of classical growth stimulating plant hormones within the naturally occurring biotic and abiotic multistress environment of higher plants. The MAPK- and phytohormone-cascades which comprise a multitude of single molecules on different signalling levels, as well as interactions...

  12. Higher Plants in Space: Microgravity Perception, Response, and Adaptation

    Science.gov (United States)

    Zheng, Hui Qiong; Han, Fei; Le, Jie

    2015-11-01

    Microgravity is a major abiotic stress in space. Its effects on plants may depend on the duration of exposure. We focused on two different phases of microgravity responses in space. When higher plants are exposed to short-term (seconds to hours) microgravity, such as on board parabolic flights and sounding rockets, their cells usually exhibit abiotic stress responses. For example, Ca 2+-, lipid-, and pH-signaling are rapidly enhanced, then the production of reactive oxygen species and other radicals increase dramatically along with changes in metabolism and auxin signaling. Under long-term (days to months) microgravity exposure, plants acclimatize to the stress by changing their metabolism and oxidative response and by enhancing other tropic responses. We conclude by suggesting that a systematic analysis of regulatory networks at the molecular level of higher plants is needed to understand the molecular signals in the distinct phases of the microgravity response and adaptation.

  13. A Plant's Response to Gravity as a Wave Guide Phenomenon

    Science.gov (United States)

    Wagner, Orvin

    1997-11-01

    Plant experimental data provides a unifying wave theory (W-wave theory) for the growth and development of plants. A plant's response to gravity is an important aspect of this theory. It appears that a plant part is tuned to the angle with which it initially grew with respect to the gravitational field and changes produce correction responses. This is true because the velocity of W-waves (whose standing waves determine plant structure) within plant tissue is found to be different in different directions (angle a) with respect to the gravitational field. I found that there are preferred values of a, namely integral multiples of near 5 degrees for some plants. Conifers apparently are more sensitive to the gravitational field than deciduous trees, in the cases studied, so their structure is determined in more detail by the gravitational field. A plant's response to gravity appears to be a fundamental phenomenon and may provide a new model for gravity that can be experimentally verified in the laboratory. Along these same lines accelerometers placed in plant tissue indicate that plants produce gravity related forces that facilitate sap flow. See the

  14. Radiation protection and safety in the Australian Defence Organisation (ADO)

    International Nuclear Information System (INIS)

    Jenks, G.J.; O'Donovan, E.J.B.

    1995-01-01

    Very few organisations have to address such a diverse and complex range of radiation safety matters as the Australian Defence Organisation. The Australian Defence Force and the Department of Defence (its military and civilian branches) have to comply with strict regulations in normal peace time activities. The Surgeon-General, to whom responsibility for policy in radiation protection and safety falls, has established a Defence Radiation Safety Committee, which in turn oversees four specialist subcommittees. Their tasks include recommending policy and doctrine in relation to radiation safety, overseeing the implementation of appropriate regulations, monitoring their compliance. generating the relevant documentation (particularly on procedures to be followed), developing and improving any necessary training courses, and providing sound technical advice whenever and to whomever required. The internal Defence regulations do not permit radiation doses to exceed those limits recommended by the Australian National Health and Medical Research Council and precautions are taken to ensure during normal peace time duties that these levels are not exceeded. At times of national emergency, the Surgeon-General provides guidance and advice to military commanders on the consequences of receiving dose levels that would not be permitted during normal peace time activities. The paper describes the methods adopted to implement such arrangements

  15. Plants' responses to drought and shade environments

    African Journals Online (AJOL)

    전병기

    Among them, drought is widely known as the main factor that limits plants' growth, productivity and development (Reddy et al., 2004; Shao et al., 2008; Li et al., 2009). Recently, drought occured frequently all over the globe due to climate changes (Khaine and Woo, 2015). Light and shade are very important environements ...

  16. Civil defence information for every home

    International Nuclear Information System (INIS)

    Joutsi, L.

    1995-01-01

    In Finland, the local authorities and the central government are responsible for the general planning of civil defence and for joint protection measures, while individual citizens and corporations are responsible for individual protection measures. In practice, housing companies and employers are required to carry out the statutory preparations needed for civil defence. Preparation for accidents can be improved, for instance, by awareness of correct actions in each situation. The most important individual protection measures are first aid, basic fire extinguishing skills, provision of shelter, and acquisition of a reserve stock of provisions at home. A reserve stock means that there is a sufficient supply of non-perishable foodstuffs, medication and water vessels for a couple of days' needs at home. A warning of imminent danger is usually given by sounding a general alarm signal. Even slight changes in radiation are reported immediately. Shelter should primarily be sought indoors. Instructions may be given on the radio, on TV and by means of loudspeakers. If there is a radiation risk, the thyroid may be protected against radioactive iodine by taking iodine tablets, but they should not be taken until so instructed by the authorities. (2 figs.)

  17. Plant stress signalling: understanding and exploiting plant-plant interactions.

    Science.gov (United States)

    Pickett, J A; Rasmussen, H B; Woodcock, C M; Matthes, M; Napier, J A

    2003-02-01

    When plants are attacked by insects, volatile chemical signals can be released, not only from the damaged parts, but also systemically from other parts of the plant and this continues after cessation of feeding by the insect. These signals are perceived by olfactory sensory mechanisms in both the herbivorous insects and their parasites. Molecular structures involved can be characterized by means of electrophysiological assays, using the insect sensory system linked to chemical analysis. Evidence is mounting that such signals can also affect neighbouring intact plants, which initiate defence by the induction of further signalling systems, such as those that increase parasitoid foraging. Furthermore, insect electrophysiology can be used in the identification of plant compounds having effects on the plants themselves. It has been found recently that certain plants can release stress signals even when undamaged, and that these can cause defence responses in intact plants. These discoveries provide the basis for new crop protection strategies, that are either delivered by genetic modification of plants or by conventionally produced plants to which the signal is externally applied. Delivery can also be made by means of mixed seed strategies in which the provoking and recipient plants are grown together. Related signalling discoveries within the rhizosphere seem set to extend these approaches into new ways of controlling weeds, by exploiting the elusive potential of allelopathy, but through signalling rather than by direct physiological effects.

  18. WRKY transcription factors in plant responses to stresses.

    Science.gov (United States)

    Jiang, Jingjing; Ma, Shenghui; Ye, Nenghui; Jiang, Ming; Cao, Jiashu; Zhang, Jianhua

    2017-02-01

    The WRKY gene family is among the largest families of transcription factors (TFs) in higher plants. By regulating the plant hormone signal transduction pathway, these TFs play critical roles in some plant processes in response to biotic and abiotic stress. Various bodies of research have demonstrated the important biological functions of WRKY TFs in plant response to different kinds of biotic and abiotic stresses and working mechanisms. However, very little summarization has been done to review their research progress. Not just important TFs function in plant response to biotic and abiotic stresses, WRKY also participates in carbohydrate synthesis, senescence, development, and secondary metabolites synthesis. WRKY proteins can bind to W-box (TGACC (A/T)) in the promoter of its target genes and activate or repress the expression of downstream genes to regulate their stress response. Moreover, WRKY proteins can interact with other TFs to regulate plant defensive responses. In the present review, we focus on the structural characteristics of WRKY TFs and the research progress on their functions in plant responses to a variety of stresses. © 2016 Institute of Botany, Chinese Academy of Sciences.

  19. Defence in Depth and Ageing Management

    Energy Technology Data Exchange (ETDEWEB)

    Fabbri, S.; Vega, G.; Diluch, A.; Versaci, R., E-mail: versaci@cnea.gov.ar [Comisión Nacional de Energía Atómica, Buenos Aires (Argentina)

    2014-10-15

    Accident prevention is the first safety priority of both designers and operators. It is achieved through the use of reliable structures, components, systems and procedures in a plant operated by personnel who are committed to a strong safety culture. For future nuclear power plants, consideration of multiple failures and severe accidents will be achieved in a more systematic and complete way from the design stage. Defence in depth (DID) consists of a hierarchical deployment of different levels of equipment and procedures in order to maintain the effectiveness of physical barriers placed between radioactive materials and workers, the public or the environment, in normal operation, anticipated operational occurrences and, for some barriers, in accidents at the plant. The primary way of preventing accidents is to achieve a high quality in design, construction and operation of the plant, and thereby to ensure that deviations from normal operation are infrequent. The best way to meet these premises of effectiveness of the barriers and the Systems, Structures and Components (SSCs) is to develop an ageing management programme to prevent potential failures and accidents. In this work we will refer to the ageing management programme for Atucha I and Atucha II power plants and to the Atucha I spent fuel storage. (author)

  20. Phytoplankton defence mechanisms: traits and trade-offs

    DEFF Research Database (Denmark)

    Pančić, Marina; Kiørboe, Thomas

    2018-01-01

    mechanisms in phytoplankton are diverse and include physiological (e.g. toxicity, bioluminescence), morphological (e.g. silica shell, colony formation), and behavioural (e.g. escape response) traits. However, the function of many of the proposed defence mechanisms remains elusive, and the costs and benefits...

  1. Review of Signal Crosstalk in Plant Stress Responses

    Science.gov (United States)

    This book was prepared to summarize the current understanding of the dynamics of plant response to biotic and abiotic stresses. The preface of the book sets the stage for the contents of the different chapters by outlining that plants defend themselves from various environmental stresses through a v...

  2. Plant Responses to Pathogen Attack: Small RNAs in Focus.

    Science.gov (United States)

    Islam, Waqar; Noman, Ali; Qasim, Muhammad; Wang, Liande

    2018-02-08

    Small RNAs (sRNA) are a significant group of gene expression regulators for multiple biological processes in eukaryotes. In plants, many sRNA silencing pathways produce extensive array of sRNAs with specialized roles. The evidence on record advocates for the functions of sRNAs during plant microbe interactions. Host sRNAs are reckoned as mandatory elements of plant defense. sRNAs involved in plant defense processes via different pathways include both short interfering RNA (siRNA) and microRNA (miRNA) that actively regulate immunity in response to pathogenic attack via tackling pathogen-associated molecular patterns (PAMPs) and other effectors. In response to pathogen attack, plants protect themselves with the help of sRNA-dependent immune systems. That sRNA-mediated plant defense responses play a role during infections is an established fact. However, the regulations of several sRNAs still need extensive research. In this review, we discussed the topical advancements and findings relevant to pathogen attack and plant defense mediated by sRNAs. We attempted to point out diverse sRNAs as key defenders in plant systems. It is hoped that sRNAs would be exploited as a mainstream player to achieve food security by tackling different plant diseases.

  3. Plant natriuretic peptides are apoplastic and paracrine stress response molecules

    KAUST Repository

    Wang, Yuhua; Gehring, Christoph A; Irving, Helen R.

    2011-01-01

    plant stress responses and that, much like in animals, peptide signaling molecules can create diverse and modular signals essential for growth, development and defense under rapidly changing environmental conditions. © 2011 The Author.

  4. Photosynthetic responses of pea plants (Pisum sativum L. cv. Little ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-08-04

    Aug 4, 2008 ... (O3) have fundamental effects on CO2 exchange by plants. ... produce responses such as reduced photosynthetic rates and earlier senescence .... quality localities treatments and two soil regimes in Riyadh city, KSA. Pn rates.

  5. An energetic defence

    International Nuclear Information System (INIS)

    Margerison, Tom

    1989-01-01

    The Director of the Nuclear Electricity Information Group answers two of the most important questions about nuclear power. The first concerns the safety of the reactors, especially following the Chernobyl accident. The risk of a reactor accident or of damage due to earthquake, terrorist attack or aircraft impact is very small and the stations have been built to withstand likely earthquakes and considerable impact. The second concerns the risk to health from radiation releases by nuclear stations. The leukemia clusters cannot certainly be ascribed to radiation levels around nuclear plants but may be due to a virus or social changes. Natural radioactive levels are higher than those from nuclear reactors or reprocessing. The risk of death due to road accident is far higher. The Director also saw an inevitable increase in the use of nuclear power worldwide. He defended the industry's health and safety record and felt that lack of public support was partly due to wrong perception of the safety record. (UK)

  6. Genetic and epigenetic control of plant heat responses

    Directory of Open Access Journals (Sweden)

    Junzhong eLiu

    2015-04-01

    Full Text Available Plants have evolved sophisticated genetic and epigenetic regulatory systems to respond quickly to unfavorable environmental conditions such as heat, cold, drought, and pathogen infections. In particular, heat greatly affects plant growth and development, immunity and circadian rhythm, and poses a serious threat to the global food supply. According to temperatures exposing, heat can be usually classified as warm ambient temperature (about 22-27℃, high temperature (27-30℃ and extremely high temperature (37-42℃, also known as heat stress for the model plant Arabidopsis thaliana. The genetic mechanisms of plant responses to heat have been well studied, mainly focusing on elevated ambient temperature-mediated morphological acclimation and acceleration of flowering, modulation of plant immunity and circadian clock by high temperatures, and thermotolerance to heat stress. Recently, great progress has been achieved on epigenetic regulation of heat responses, including DNA methylation, histone modifications, histone variants, ATP-dependent chromatin remodeling, histone chaperones, small RNAs, long non-coding RNAs and other undefined epigenetic mechanisms. These epigenetic modifications regulate the expression of heat-responsive genes and function to prevent heat-related damage. This review focuses on recent progresses regarding the genetic and epigenetic control of heat responses in plants, and pays more attention to the role of the major epigenetic mechanisms in plant heat responses. Further research perspectives are also discussed.

  7. Plant Responses to Abiotic Stress Regulated by Histone Deacetylases

    Directory of Open Access Journals (Sweden)

    Ming Luo

    2017-12-01

    Full Text Available In eukaryotic cells, histone acetylation and deacetylation play an important role in the regulation of gene expression. Histone acetylation levels are modulated by histone acetyltransferases and histone deacetylases (HDACs. Recent studies indicate that HDACs play essential roles in the regulation of gene expression in plant response to environmental stress. In this review, we discussed the recent advance regarding the plant HDACs and their functions in the regulation of abiotic stress responses. The role of HDACs in autophagy was also discussed.

  8. The Fukushima Daiichi Nuclear Power Plant Accident: OECD/NEA Nuclear Safety Response and Lessons Learnt

    International Nuclear Information System (INIS)

    2013-01-01

    Following the March 2011 accident at the Fukushima Daiichi nuclear power plant, all NEA member countries took early action to ensure and confirm the continued safety of their nuclear power plants and the protection of the public. After these preliminary safety reviews, all countries with nuclear facilities carried out comprehensive safety reviews, often referred to as 'stress tests', which reassessed safety margins of nuclear facilities with a primary focus on challenges related to conditions experienced at the Fukushima Daiichi nuclear power plant, for example extreme external events and the loss of safety functions, or capabilities to cope with severe accidents. As appropriate, improvements are being made to safety and emergency response systems to ensure that nuclear power plants are capable of withstanding events that lead to loss of electrical power and/or cooling capability. In the weeks following the accident, the NEA immediately began establishing expert groups in the nuclear safety and radiological protection areas, as well as contributing to information exchange with the Japanese authorities and other international organisations. It promptly provided a forum for high-level decision makers and regulators within the G8-G20 frameworks. The NEA actions taken at the international level in response to the accident have been carried out primarily by the three NEA standing technical committees concerned with nuclear and radiation safety issues - the Committee on Nuclear Regulatory Activities (CNRA), the Committee on the Safety of Nuclear Installations (CSNI) and the Committee on Radiation Protection and Public Health (CRPPH) - under the leadership of the CNRA. More than two years following the accident, the NEA continues to assist the Japanese authorities in dealing with their nuclear safety and recovery efforts as well as to facilitate international co-operation on nuclear safety and radiological protection matters. It is strongly supporting the establishment of

  9. Responsiveness of performance and morphological traits to experimental submergence predicts field distribution pattern of wetland plants

    NARCIS (Netherlands)

    Luo, Fang-Li; Huang, Lin; Lei, Ting; Xue, Wei; Li, Hong-Li; Yu, Fei-Hai; Cornelissen, J.H.C.

    2016-01-01

    Question: Plant trait mean values and trait responsiveness to different environmental regimes are both important determinants of plant field distribution, but the degree to which plant trait means vs trait responsiveness predict plant distribution has rarely been compared quantitatively. Because

  10. Site response calculations for nuclear power plants

    International Nuclear Information System (INIS)

    Wight, L.H.

    1975-01-01

    Six typical sites consisting of three soil profiles with average shear wave velocities of 800, 1800, and 5000 ft/sec as well as two soil depths of 200 and 400 ft were considered. Seismic input to these sites was a synthetic accelerogram applied at the surface and corresponding to a statistically representative response spectrum. The response of each of these six sites to this input was calculated with the SHAKE program. The results of these calculations are presented

  11. Plant response to heavy metals and organic pollutants in cell culture and at whole plant level

    Energy Technology Data Exchange (ETDEWEB)

    Golan-Goldhirsh, A.; Barazani, O. [Ben-Gurion Univ. of The Negev, The Jacob Blaustein Inst. for Desert Research, Albert Katz Dept. of Dryland Biotechnologies, Desert Plant Biotechnology Lab., Sede Boqer Campus (Israel); Nepovim, A.; Soudek, P.; Vanek, T. [Inst. of Organic Chemistry and Biochemistry (Czech Republic); Smrcek, S.; Dufkova, L.; Krenkova, S. [Faculty of Natural Sciences, Charles Univ. (Czech Republic); Yrjala, K. [Univ. of Helsinki, Dept. of Biosciences, Div. of General Microbiology, Helsinki (Finland); Schroeder, P. [Inst. for Soil Ecology, GSF National Research Center for Environment and Health, Neuherberg, Oberschleissheim (Germany)

    2004-07-01

    Background. Increasing awareness in the last decade concerning environmental quality had prompted research into 'green solutions' for soil and water remediation, progressing from laboratory in vitro experiments to pot and field trials. In vitro cell culture experiments provide a convenient system to study basic biological processes, by which biochemical pathways, enzymatic activity and metabolites can be specifically studied. However, it is difficult to relate cell cultures, calli or even hydroponic experiments to the whole plant response to pollutant stress. In the field, plants are exposed to additional a-biotic and biotic factors, which complicate further plant response. Hence, we often see that in vitro selected species perform poorly under soil and field conditions. Soil physical and chemical properties, plant-mycorrhizal association and soil-microbial activity affect the process of contaminant degradation by plants and/or microorganisms, pointing to the importance of pot and field experiments. Objective. This paper is a joint effort of a group of scientists in COST action 837. It represents experimental work and an overview on plant response to environmental stress from in vitro tissue culture to whole plant experiments in soil. Results. Results obtained from in vitro plant tissue cultures and whole plant hydroponic experiments indicate the phytoremediation potential of different plant species and the biochemical mechanisms involved in plant tolerance. In pot experiments, several selected desert plant species, which accumulated heavy metal in hydroponic systems, succeeded in accumulating the heavy metal in soil conditions as well. Conclusions and recommendations. In vitro plant tissue cultures provide a useful experimental system for the study of the mechanisms involved in the detoxification of organic and heavy metal pollutants. However, whole plant experimental systems, as well as hydroponics followed by pot and field trials, are essential when

  12. Interaction of Medicago truncatula Lysin Motif Receptor-Like Kinases, NFP and LYK3, Produced in Nicotiana benthamiana Induces Defence-Like Responses

    NARCIS (Netherlands)

    Pietraszewska-Bogiel, A.; Lefebvre, B.; Koini, A.M.; Klaus-Heisen, D.; Takken, F.L.W.; Geurts, R.; Cullimore, J.V.; Gadella, Th.W.J.

    2013-01-01

    Receptor(-like) kinases with Lysin Motif (LysM) domains in their extracellular region play crucial roles during plant interactions with microorganisms; e.g. Arabidopsis thaliana CERK1 activates innate immunity upon perception of fungal chitin/chitooligosaccharides, whereas Medicago truncatula NFP

  13. Plant hydraulic diversity buffers forest ecosystem responses to drought

    Science.gov (United States)

    Anderegg, W.; Konings, A. G.; Trugman, A. T.; Pacala, S. W.; Yu, K.; Sulman, B. N.; Sperry, J.; Bowling, D. R.

    2017-12-01

    Drought impacts carbon, water, and energy cycles in forests and may pose a fundamental threat to forests in future climates. Plant hydraulic transport of water is central to tree drought responses, including curtailing of water loss and the risk of mortality during drought. The effect of biodiversity on ecosystem function has typically been examined in grasslands, yet the diversity of plant hydraulic strategies may influence forests' response to drought. In a combined analysis of eddy covariance measurements, remote-sensing data of plant water content variation, model simulations, and plant hydraulic trait data, we test the degree to which plant water stress schemes influence the carbon cycle and how hydraulic diversity within and across ecosystems affects large-scale drought responses. We find that current plant functional types are not well-suited to capture hydraulic variation and that higher hydraulic diversity buffers ecosystem variation during drought. Our results demonstrate that tree functional diversity, particularly hydraulic diversity, may be critical to simulate in plant functional types in current land surface model projections of future vegetation's response to climate extremes.

  14. Do plants modulate biomass allocation in response to petroleum pollution?

    Science.gov (United States)

    Nie, Ming; Yang, Qiang; Jiang, Li-Fen; Fang, Chang-Ming; Chen, Jia-Kuan; Li, Bo

    2010-01-01

    Biomass allocation is an important plant trait that responds plastically to environmental heterogeneities. However, the effects on this trait of pollutants owing to human activities remain largely unknown. In this study, we investigated the response of biomass allocation of Phragmites australis to petroleum pollution by a 13CO2 pulse-labelling technique. Our data show that plant biomass significantly decreased under petroleum pollution, but the root–shoot ratio for both plant biomass and 13C increased with increasing petroleum concentration, suggesting that plants could increase biomass allocation to roots in petroleum-polluted soil. Furthermore, assimilated 13C was found to be significantly higher in soil, microbial biomass and soil respiration after soils were polluted by petroleum. These results suggested that the carbon released from roots is rapidly turned over by soil microbes under petroleum pollution. This study found that plants can modulate biomass allocation in response to petroleum pollution. PMID:20484231

  15. In defence of andragogy.

    Science.gov (United States)

    Milligan, F

    1995-02-01

    This paper supports the continued use of the term andragogy in Project 2000 nurse education programmes. It is argued that the theory of andragogy, and its supporting philosophy, methods, and research, are consistent with both the means and ends of contemporary nurse education. Some of the recent pressure felt in relation to use of alternative terms, such as critical pedagogy, are linked to wider socio-political influences and it is argued that it is essentially a sign of the times that andragogy has now come under threat. The call, from some, for a return to pedagogy is also seen as an attempt to reassert an increased degree of control over the student by those educationalists. This article is also a response to the article by Philip Darbyshire (1993) which questions the viability and relevance of the term andragogy.

  16. Simple growth patterns can create complex trajectories for the ontogeny of constitutive chemical defences in seaweeds.

    Directory of Open Access Journals (Sweden)

    Nicholas A Paul

    Full Text Available All of the theory and most of the data on the ecology and evolution of chemical defences derive from terrestrial plants, which have considerable capacity for internal movement of resources. In contrast, most macroalgae--seaweeds--have no or very limited capacity for resource translocation, meaning that trade-offs between growth and defence, for example, should be localised rather than systemic. This may change the predictions of chemical defence theories for seaweeds. We developed a model that mimicked the simple growth pattern of the red seaweed Asparagopsis armata which is composed of repeating clusters of somatic cells and cells which contain deterrent secondary chemicals (gland cells. To do this we created a distinct growth curve for the somatic cells and another for the gland cells using empirical data. The somatic growth function was linked to the growth function for defence via differential equations modelling, which effectively generated a trade-off between growth and defence as these neighbouring cells develop. By treating growth and defence as separate functions we were also able to model a trade-off in growth of 2-3% under most circumstances. However, we found contrasting evidence for this trade-off in the empirical relationships between growth and defence, depending on the light level under which the alga was cultured. After developing a model that incorporated both branching and cell division rates, we formally demonstrated that positive correlations between growth and defence are predicted in many circumstances and also that allocation costs, if they exist, will be constrained by the intrinsic growth patterns of the seaweed. Growth patterns could therefore explain contrasting evidence for cost of constitutive chemical defence in many studies, highlighting the need to consider the fundamental biology and ontogeny of organisms when assessing the allocation theories for defence.

  17. On-line acquisition of plant related and environmental parameters (plant monitoring) in gerbera: determining plant responses

    OpenAIRE

    Baas, R.; Slootweg, G.

    2004-01-01

    For on-line plant monitoring equipment to be functional in commercial glasshouse horticulture, relations between sensor readings and plant responses on both the short (days) and long term (weeks) are required. For this reason, systems were installed to monitor rockwool grown gerbera plants on a minute-to-minute basis from July 2002 until April 2003. Data collected included, amongst others, crop transpiration from lysimeter data (2 m2), canopy temperature using infrared sensors, rockwool water...

  18. Plant-plant interactions mediate the plastic and genotypic response of Plantago asiatica to CO

    NARCIS (Netherlands)

    Loon, Van 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

  19. Stomatal Blue Light Response Is Present in Early Vascular Plants.

    Science.gov (United States)

    Doi, Michio; Kitagawa, Yuki; Shimazaki, Ken-ichiro

    2015-10-01

    Light is a major environmental factor required for stomatal opening. Blue light (BL) induces stomatal opening in higher plants as a signal under the photosynthetic active radiation. The stomatal BL response is not present in the fern species of Polypodiopsida. The acquisition of a stomatal BL response might provide competitive advantages in both the uptake of CO2 and prevention of water loss with the ability to rapidly open and close stomata. We surveyed the stomatal opening in response to strong red light (RL) and weak BL under the RL with gas exchange technique in a diverse selection of plant species from euphyllophytes, including spermatophytes and monilophytes, to lycophytes. We showed the presence of RL-induced stomatal opening in most of these species and found that the BL responses operated in all euphyllophytes except Polypodiopsida. We also confirmed that the stomatal opening in lycophytes, the early vascular plants, is driven by plasma membrane proton-translocating adenosine triphosphatase and K(+) accumulation in guard cells, which is the same mechanism operating in stomata of angiosperms. These results suggest that the early vascular plants respond to both RL and BL and actively regulate stomatal aperture. We also found three plant species that absolutely require BL for both stomatal opening and photosynthetic CO2 fixation, including a gymnosperm, C. revoluta, and the ferns Equisetum hyemale and Psilotum nudum. © 2015 American Society of Plant Biologists. All Rights Reserved.

  20. ROLE OF ETHYLENE IN RESPONSES OF PLANTS TO NITROGEN AVAILABILITY

    Directory of Open Access Journals (Sweden)

    M Iqbal R Khan

    2015-10-01

    Full Text Available Ethylene is a plant hormone involved in several physiological processes and regulates the plant development during the whole life. Stressful conditions usually activate ethylene biosynthesis and signalling in plants. The availability of nutrients, shortage or excess, influences plant metabolism and ethylene plays an important role in plant adaptation under suboptimal conditions. Among the plant nutrients, the nitrogen (N is one the most important mineral element required for plant growth and development. The availability of N significantly influences plant metabolism, including ethylene biology. The interaction between ethylene and N affects several physiological process such as leaf gas exchanges, roots architecture, leaf, fruits and flowers development. Low plant N use efficiency leads to N loss and N deprivation, which affect ethylene biosynthesis and tissues sensitivity, inducing cell damage and ultimately lysis. Plants may respond differently to N availability balancing ethylene production through its signalling network. This review discusses the recent advances in the interaction between N availability and ethylene at whole plant and different organ levels, and explores how N availability induces ethylene biology and plant responses. Exogenously applied ethylene seems to cope the stress conditions and improves plant physiological performance. This can be explained considering the expression of ethylene biosynthesis and signalling genes under different N availability. A greater understanding of the regulation of N by means of ethylene modulation may help to increase N use efficiency and directly influence crop productivity under conditions of limited N availability, leading to positive effects on the environment. Moreover, efforts should be focused on the effect of N deficiency or excess in fruit trees, where ethylene can have detrimental effects especially during postharvest.

  1. Meteorological considerations in emergency response capability at nuclear power plant

    International Nuclear Information System (INIS)

    Fairobent, J.E.

    1985-01-01

    Meteorological considerations in emergency response at nuclear power plants are discussed through examination of current regulations and guidance documents, including discussion of the rationale for current regulatory requirements related to meteorological information for emergency response. Areas discussed include: major meteorological features important to emergency response; onsite meteorological measurements programs, including redundant and backup measurements; access to offsite sources of meteorological information; consideration of real-time and forecast conditions and atmospheric dispersion modeling

  2. Aquatic emergency response model at the Savannah River Plant

    International Nuclear Information System (INIS)

    Hayes, D.W.

    1987-01-01

    The Savannah River Plant emergency response plans include a stream/river emergency response model to predict travel times, maximum concentrations, and concentration distributions as a function of time at selected downstream/river locations from each of the major SRP installations. The menu driven model can be operated from any of the terminals that are linked to the real-time computer monitoring system for emergency response

  3. Airborne signals by Trichoderma fungi stimulate iron uptake responses in roots resulting in priming of jasmonic acid-dependent defences in shoots of Arabidopsis thaliana and Solanum lycopersicum

    NARCIS (Netherlands)

    Martínez-Medina, Ainhoa; Van Wees, Saskia C M; Pieterse, Corné M J

    2017-01-01

    Root colonization by Trichoderma fungi can trigger induced systemic resistance (ISR). In Arabidopsis, Trichoderma-ISR relies on the transcription factor MYB72, which plays a dual role in the onset of ISR and the activation of Fe uptake responses. Volatile compounds (VCs) from rhizobacteria are

  4. The reconfiguration of the SA defence industry in the post-2015-defence review environment: prospects & challenges

    CSIR Research Space (South Africa)

    Khanyile, Moses

    2017-10-01

    Full Text Available IMPLICATIONS • Licence category (FSB) • Credit licence (NCR) • Forex Licence (SARB) Armscor & AMD Initiative: Establishment of the Defence Industry Fund (DIF) WAY FORWARD Finalisation of the Defence Industry Strategy Drafting...

  5. Biocontrol traits of plant growth suppressive arbuscular mycorrhizal fungi against root rot in tomato caused by Pythium aphanidermatum

    DEFF Research Database (Denmark)

    Larsen, John; Graham, James H.; Cubero, Jaime

    2012-01-01

    Arbuscular mycorrhizal (AM) fungi known to cause plant growth depressions in tomato were examined for their biocontrol effects against root rot caused by Pythium aphanidermatum. The main hypothesis was that plant growth suppressive AM fungi would elicit a defence response in the host plant reduci...

  6. Defence in depth by 'Leittechnique' systems with graded intelligence

    International Nuclear Information System (INIS)

    Aleite, W.

    1983-01-01

    In the past, only two types of nuclear power plant instrumentation and control systems were in use in the Federal Republic of Germany (FRG): safety systems and operational systems. Present nuclear power plant 'Leittechnique' systems in the FRG have been expanded from this 'black-and-white' status to multiple-grade systems with respect to safety, qualification requirements and intelligence. The extensive experience of the past has encouraged the rule-making committees - representing all parties working in the nuclear field - to differentiate between the protection limitations and condition limitations of the reactor protection system on one hand and the information systems (including the accident monitoring and alarm system) of different safety importance on the other, assuming additional extensive application of non-safety-grade operational Leittechnique systems. These definitions of categories are in accordance with international practice and enable designers to apply 'echelons of defence', composed of equipment of all categories, in accordance with 'defence-in-depth' concepts. They also simplify the introduction of computerized equipment, especially in the lower safety categories. Status, background and reasons of the introduction, as well as typical defence-in-depth modes, of the first running Leittechnique system of this kind (in the Grafenrheinfeld nuclear power plant) and especially their different tasks in disturbance handling are described. The international situation and future developments are briefly characterized. (author)

  7. Piloting Snapchat for Finnish Defence Forces

    OpenAIRE

    Immonen, Helena

    2016-01-01

    This thesis is about piloting Snapchat for Finnish Defence Forces. The goals for the thesis are to find out how Snapchat can be used as part of Finnish Defence Forces’ social media communication and strategy. Conscripts are the most important target group for social media communication in the Defence Forces. Young conscripts are the main target group for Snapchat. This thesis is theoretically based on organizational communication, stakeholder communication and social media communicati...

  8. Driving Danish Defence Towards Political Goals

    Science.gov (United States)

    2016-06-10

    discuss the political agreement.90 The Defence Chief of Staff is interviewed in the same paper along the same lines, where he provides an in- depth ...DRIVING DANISH DEFENCE TOWARDS POLITICAL GOALS A thesis presented to the Faculty of the U.S. Army Command and General Staff...4. TITLE AND SUBTITLE Driving Danish Defence Towards Political Goals 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6

  9. Methodology for Assessment of Inertial Response from Wind Power Plants

    DEFF Research Database (Denmark)

    Altin, Müfit; Teodorescu, Remus; Bak-Jensen, Birgitte

    2012-01-01

    High wind power penetration levels result in additional requirements from wind power in order to improve frequency stability. Replacement of conventional power plants with wind power plants reduces the power system inertia due to the wind turbine technology. Consequently, the rate of change...... of frequency and the maximum frequency deviation increase after a disturbance such as generation loss, load increase, etc. Having no inherent inertial response, wind power plants need additional control concepts in order to provide an additional active power following a disturbance. Several control concepts...... have been implemented in the literature, but the assessment of these control concepts with respect to power system requirements has not been specified. In this paper, a methodology to assess the inertial response from wind power plants is proposed. Accordingly, the proposed methodology is applied...

  10. Interactions between plant hormones and heavy metals responses.

    Science.gov (United States)

    Bücker-Neto, Lauro; Paiva, Ana Luiza Sobral; Machado, Ronei Dorneles; Arenhart, Rafael Augusto; Margis-Pinheiro, Marcia

    2017-01-01

    Heavy metals are natural non-biodegradable constituents of the Earth's crust that accumulate and persist indefinitely in the ecosystem as a result of human activities. Since the industrial revolution, the concentration of cadmium, arsenic, lead, mercury and zinc, amongst others, have increasingly contaminated soil and water resources, leading to significant yield losses in plants. These issues have become an important concern of scientific interest. Understanding the molecular and physiological responses of plants to heavy metal stress is critical in order to maximize their productivity. Recent research has extended our view of how plant hormones can regulate and integrate growth responses to various environmental cues in order to sustain life. In the present review we discuss current knowledge about the role of the plant growth hormones abscisic acid, auxin, brassinosteroid and ethylene in signaling pathways, defense mechanisms and alleviation of heavy metal toxicity.

  11. Interactions between plant hormones and heavy metals responses

    Directory of Open Access Journals (Sweden)

    Lauro Bücker-Neto

    2017-04-01

    Full Text Available Abstract Heavy metals are natural non-biodegradable constituents of the Earth's crust that accumulate and persist indefinitely in the ecosystem as a result of human activities. Since the industrial revolution, the concentration of cadmium, arsenic, lead, mercury and zinc, amongst others, have increasingly contaminated soil and water resources, leading to significant yield losses in plants. These issues have become an important concern of scientific interest. Understanding the molecular and physiological responses of plants to heavy metal stress is critical in order to maximize their productivity. Recent research has extended our view of how plant hormones can regulate and integrate growth responses to various environmental cues in order to sustain life. In the present review we discuss current knowledge about the role of the plant growth hormones abscisic acid, auxin, brassinosteroid and ethylene in signaling pathways, defense mechanisms and alleviation of heavy metal toxicity.

  12. A role for SR proteins in plant stress responses.

    Science.gov (United States)

    Duque, Paula

    2011-01-01

    Members of the SR (serine/arginine-rich) protein gene family are key players in the regulation of alternative splicing, an important means of generating proteome diversity and regulating gene expression. In plants, marked changes in alternative splicing are induced by a wide variety of abiotic stresses, suggesting a role for this highly versatile gene regulation mechanism in the response to environmental cues. In support of this notion, the expression of plant SR proteins is stress-regulated at multiple levels, with environmental signals controlling their own alternative splicing patterns, phosphorylation status and subcellular distribution. Most importantly, functional links between these RNA-binding proteins and plant stress tolerance are beginning to emerge, including a role in the regulation of abscisic acid (ABA) signaling. Future identification of the physiological mRNA targets of plant SR proteins holds much promise for the elucidation of the molecular mechanisms underlying their role in the response to abiotic stress.

  13. Induced defences alter the strength and direction of natural selection on reproductive traits in common milkweed.

    Science.gov (United States)

    Thompson, K A; Cory, K A; Johnson, M T J

    2017-06-01

    Evolutionary biologists have long sought to understand the ecological processes that generate plant reproductive diversity. Recent evidence indicates that constitutive antiherbivore defences can alter natural selection on reproductive traits, but it is unclear whether induced defences will have the same effect and whether reduced foliar damage in defended plants is the cause of this pattern. In a factorial field experiment using common milkweed, Asclepias syriaca L., we induced plant defences using jasmonic acid (JA) and imposed foliar damage using scissors. We found that JA-induced plants experienced selection for more inflorescences that were smaller in size (fewer flowers), whereas control plants only experienced a trend towards selection for larger inflorescences (more flowers); all effects were independent of foliar damage. Our results demonstrate that induced defences can alter both the strength and direction of selection on reproductive traits, and suggest that antiherbivore defences may promote the evolution of plant reproductive diversity. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

  14. Real-time information support for managing plant emergency responses

    International Nuclear Information System (INIS)

    Cain, D.G.; Lord, R.J.; Wilkinson, C.D.

    1983-01-01

    The Three Mile Island Unit 2 accident highlighted the need to develop a systematic approach to managing plant emergency responses, to identify a better decision-making process, and to implement real-time information support for decision-making. The overall process management function is described and general information requirements for management of plant emergencies are identified. Basic information systems are being incorporated and future extensions and problem areas are discussed. (U.K.)

  15. Transcriptional plant responses critical for resistance towards necrotrophic pathogens

    Directory of Open Access Journals (Sweden)

    Rainer P. Birkenbihl

    2011-11-01

    Full Text Available Plant defenses aimed at necrotrophic pathogens appear to be genetically complex. Despite the apparent lack of a specific recognition of such necrotrophs by products of major R genes, biochemical, molecular, and genetic studies, in particular using the model plant Arabidopsis, have uncovered numerous host components critical for the outcome of such interactions. Although the JA signaling pathway plays a central role in plant defense towards necrotrophs additional signaling pathways contribute to the plant response network. Transcriptional reprogramming is a vital part of the host defense machinery and several key regulators have recently been identified. Some of these transcription factors positively affect plant resistance whereas others play a role in enhancing host susceptibility towards these phytopathogens.

  16. ‘Omics’ and Plant Responses to Botrytis cinerea

    Directory of Open Access Journals (Sweden)

    Synan F. AbuQamar

    2016-11-01

    Full Text Available Botrytis cinerea is a dangerous plant pathogenic fungus with wide host ranges. This aggressive pathogen uses multiple weapons to invade and cause serious damages on its host plants. The continuing efforts of how to solve the puzzle of the multigenic nature of B. cinerea’s pathogenesis and plant defense mechanisms against the disease caused by this mold, the integration of omic approaches, including genomics, transcriptomics, proteomics and metabolomics, along with functional analysis could be a potential solution. Omic studies will provide a foundation for development of genetic manipulation and breeding programs that will eventually lead to crop improvement and protection. In this mini-review, we will highlight the current progresses in research in plant stress responses to B. cinerea using high-throughput omic technologies. We also discuss the opportunities that omic technologies can provide to research on B. cinerea-plant interactions as an example showing the impacts of omics on agricultural research.

  17. The Ability of the Trinidad and Tobago Defence Force (TTDF) Logistics Infrastructure to Support Requirements in Response to Humanitarian and Disaster Relief (HADR)

    Science.gov (United States)

    2017-06-09

    Jamaica Coalition of Service Industries, “Trained Household Helpers Can Now move Freely Across the Region,” Jamaica Observer, 14 February 2014, accessed...17 April 2017, http://jamaicacsi.org/trained-household- helpers -can-now-move-freely-across- the-region/. 6 The CARICOM’s main purposes are to...three response sectors that the military is especially capable of assuming during a disaster mission: 1. Special skills corresponding to assistance

  18. Recent Molecular Advances on Downstream Plant Responses to Abiotic Stress

    Directory of Open Access Journals (Sweden)

    Cláudia Regina Batista de Souza

    2012-07-01

    Full Text Available Abiotic stresses such as extremes of temperature and pH, high salinity and drought, comprise some of the major factors causing extensive losses to crop production worldwide. Understanding how plants respond and adapt at cellular and molecular levels to continuous environmental changes is a pre-requisite for the generation of resistant or tolerant plants to abiotic stresses. In this review we aimed to present the recent advances on mechanisms of downstream plant responses to abiotic stresses and the use of stress-related genes in the development of genetically engineered crops.

  19. Plant responsiveness to root-root communication of stress cues.

    Science.gov (United States)

    Falik, Omer; Mordoch, Yonat; Ben-Natan, Daniel; Vanunu, Miriam; Goldstein, Oron; Novoplansky, Ariel

    2012-07-01

    Phenotypic plasticity is based on the organism's ability to perceive, integrate and respond to multiple signals and cues informative of environmental opportunities and perils. A growing body of evidence demonstrates that plants are able to adapt to imminent threats by perceiving cues emitted from their damaged neighbours. Here, the hypothesis was tested that unstressed plants are able to perceive and respond to stress cues emitted from their drought- and osmotically stressed neighbours and to induce stress responses in additional unstressed plants. Split-root Pisum sativum, Cynodon dactylon, Digitaria sanguinalis and Stenotaphrum secundatum plants were subjected to osmotic stress or drought while sharing one of their rooting volumes with an unstressed neighbour, which in turn shared its other rooting volume with additional unstressed neighbours. Following the kinetics of stomatal aperture allowed testing for stress responses in both the stressed plants and their unstressed neighbours. In both P. sativum plants and the three wild clonal grasses, infliction of osmotic stress or drought caused stomatal closure in both the stressed plants and in their unstressed neighbours. While both continuous osmotic stress and drought induced prolonged stomatal closure and limited acclimation in stressed plants, their unstressed neighbours habituated to the stress cues and opened their stomata 3-24 h after the beginning of stress induction. The results demonstrate a novel type of plant communication, by which plants might be able to increase their readiness to probable future osmotic and drought stresses. Further work is underway to decipher the identity and mode of operation of the involved communication vectors and to assess the potential ecological costs and benefits of emitting and perceiving drought and osmotic stress cues under various ecological scenarios.

  20. A plant's perspective of extremes: terrestrial plant responses to changing climatic variability.

    Science.gov (United States)

    Reyer, Christopher P O; Leuzinger, Sebastian; Rammig, Anja; Wolf, Annett; Bartholomeus, Ruud P; Bonfante, Antonello; de Lorenzi, Francesca; Dury, Marie; Gloning, Philipp; Abou Jaoudé, Renée; Klein, Tamir; Kuster, Thomas M; Martins, Monica; Niedrist, Georg; Riccardi, Maria; Wohlfahrt, Georg; de Angelis, Paolo; de Dato, Giovanbattista; François, Louis; Menzel, Annette; Pereira, Marízia

    2013-01-01

    We review observational, experimental, and model results on how plants respond to extreme climatic conditions induced by changing climatic variability. Distinguishing between impacts of changing mean climatic conditions and changing climatic variability on terrestrial ecosystems is generally underrated in current studies. The goals of our review are thus (1) to identify plant processes that are vulnerable to changes in the variability of climatic variables rather than to changes in their mean, and (2) to depict/evaluate available study designs to quantify responses of plants to changing climatic variability. We find that phenology is largely affected by changing mean climate but also that impacts of climatic variability are much less studied, although potentially damaging. We note that plant water relations seem to be very vulnerable to extremes driven by changes in temperature and precipitation and that heat-waves and flooding have stronger impacts on physiological processes than changing mean climate. Moreover, interacting phenological and physiological processes are likely to further complicate plant responses to changing climatic variability. Phenological and physiological processes and their interactions culminate in even more sophisticated responses to changing mean climate and climatic variability at the species and community level. Generally, observational studies are well suited to study plant responses to changing mean climate, but less suitable to gain a mechanistic understanding of plant responses to climatic variability. Experiments seem best suited to simulate extreme events. In models, temporal resolution and model structure are crucial to capture plant responses to changing climatic variability. We highlight that a combination of experimental, observational, and/or modeling studies have the potential to overcome important caveats of the respective individual approaches. © 2012 Blackwell Publishing Ltd.

  1. Plant responses to Agrobacterium tumefaciens and crown gall development

    Science.gov (United States)

    Gohlke, Jochen; Deeken, Rosalia

    2014-01-01

    Agrobacterium tumefaciens causes crown gall disease on various plant species by introducing its T-DNA into the genome. Therefore, Agrobacterium has been extensively studied both as a pathogen and an important biotechnological tool. The infection process involves the transfer of T-DNA and virulence proteins into the plant cell. At that time the gene expression patterns of host plants differ depending on the Agrobacterium strain, plant species and cell-type used. Later on, integration of the T-DNA into the plant host genome, expression of the encoded oncogenes, and increase in phytohormone levels induce a fundamental reprogramming of the transformed cells. This results in their proliferation and finally formation of plant tumors. The process of reprogramming is accompanied by altered gene expression, morphology and metabolism. In addition to changes in the transcriptome and metabolome, further genome-wide (“omic”) approaches have recently deepened our understanding of the genetic and epigenetic basis of crown gall tumor formation. This review summarizes the current knowledge about plant responses in the course of tumor development. Special emphasis is placed on the connection between epigenetic, transcriptomic, metabolomic, and morphological changes in the developing tumor. These changes not only result in abnormally proliferating host cells with a heterotrophic and transport-dependent metabolism, but also cause differentiation and serve as mechanisms to balance pathogen defense and adapt to abiotic stress conditions, thereby allowing the coexistence of the crown gall and host plant. PMID:24795740

  2. Exploring the Response of Plants Grown under Uranium Stress

    Energy Technology Data Exchange (ETDEWEB)

    Doustaly, Fany; Berthet, Serge; Bourguignon, Jacques [CEA, iRTSV, Laboratoire de Physiologie Cellulaire Vegetale, UMR 5168 CEA-CNRS-INRA-Univ. Grenoble Alpes (France); Combes, Florence; Vandenbrouck, Yves [CEA, iRTSV, Laboratoire de Biologie a Grande Echelle, EDyP, CEA-Grenoble (France); Carriere, Marie [CEA, INAC, LAN, UMR E3 CEA-Universite Joseph Fourier, Grenoble (France); Vavasseur, Alain [CEA, IBEB, LBDP, Saint Paul lez Durance, CEA Cadarache (France)

    2014-07-01

    Uranium is a natural element which is mainly redistributed in the environment due to human activity, including accidents and spillages. Plants may be useful in cleaning up after incidents, although little is yet known about the relationship between uranium speciation and plant response. We analyzed the impact of different uranium (U) treatments on three plant species namely sunflower, oilseed rape and wheat. Using inductively coupled plasma mass spectrometry elemental analysis, together with a panel of imaging techniques including scanning electron microscopy coupled with energy dispersive spectroscopy, transmission electron microscopy and particle-induced X-ray emission spectroscopy, we have recently shown how chemical speciation greatly influences the accumulation and distribution of U in plants. Uranyl (UO{sub 2}{sup 2+} free ion) is the predominant mobile form in soil surface at low pH in absence of ligands. With the aim to characterize the early plant response to U exposure, complete Arabidopsis transcriptome microarray experiments were conducted on plants exposed to 50 μM uranyl nitrate for 2, 6 and 30 h and highlighted a set of 111 genes with modified expression at these three time points. Quantitative real-time RT-PCR experiments confirmed and completed CATMA micro-arrays results allowing the characterization of biological processes perturbed by U. Functional categorization of deregulated genes emphasizes oxidative stress, cell wall biosynthesis and hormone biosynthesis and signaling. We showed that U stress is perceived by plant cells like a phosphate starvation stress since several phosphate deprivation marker genes were deregulated by U and also highlighted perturbation of iron homeostasis by U. Hypotheses are presented to explain how U perturbs the iron uptake and signaling response. These results give preliminary insights into the pathways affected by uranyl uptake, which will be of interest for engineering plants to help clean areas contaminated with

  3. Regulation of phosphate starvation responses in higher plants.

    Science.gov (United States)

    Yang, Xiao Juan; Finnegan, Patrick M

    2010-04-01

    Phosphorus (P) is often a limiting mineral nutrient for plant growth. Many soils worldwide are deficient in soluble inorganic phosphate (P(i)), the form of P most readily absorbed and utilized by plants. A network of elaborate developmental and biochemical adaptations has evolved in plants to enhance P(i) acquisition and avoid starvation. Controlling the deployment of adaptations used by plants to avoid P(i) starvation requires a sophisticated sensing and regulatory system that can integrate external and internal information regarding P(i) availability. In this review, the current knowledge of the regulatory mechanisms that control P(i) starvation responses and the local and long-distance signals that may trigger P(i) starvation responses are discussed. Uncharacterized mutants that have P(i)-related phenotypes and their potential to give us additional insights into regulatory pathways and P(i) starvation-induced signalling are also highlighted and assessed. An impressive list of factors that regulate P(i) starvation responses is now available, as is a good deal of knowledge regarding the local and long-distance signals that allow a plant to sense and respond to P(i) availability. However, we are only beginning to understand how these factors and signals are integrated with one another in a regulatory web able to control the range of responses demonstrated by plants grown in low P(i) environments. Much more knowledge is needed in this agronomically important area before real gains can be made in improving P(i) acquisition in crop plants.

  4. Ionic signaling in plant responses to gravity and touch

    Science.gov (United States)

    Fasano, Jeremiah M.; Massa, Gioia D.; Gilroy, Simon

    2002-01-01

    Touch and gravity are two of the many stimuli that plants must integrate to generate an appropriate growth response. Due to the mechanical nature of both of these signals, shared signal transduction elements could well form the basis of the cross-talk between these two sensory systems. However, touch stimulation must elicit signaling events across the plasma membrane whereas gravity sensing is thought to represent transformation of an internal force, amyloplast sedimentation, to signal transduction events. In addition, factors such as turgor pressure and presence of the cell wall may also place unique constraints on these plant mechanosensory systems. Even so, the candidate signal transduction elements in both plant touch and gravity sensing, changes in Ca2+, pH and membrane potential, do mirror the known ionic basis of signaling in animal mechanosensory cells. Distinct spatial and temporal signatures of Ca2+ ions may encode information about the different mechanosignaling stimuli. Signals such as Ca2+ waves or action potentials may also rapidly transfer information perceived in one cell throughout a tissue or organ leading to the systemic reactions characteristic of plant touch and gravity responses. Longer-term growth responses are likely sustained via changes in gene expression and asymmetries in compounds such as inositol-1,4,5-triphosphate (IP3) and calmodulin. Thus, it seems likely that plant mechanoperception involves both spatial and temporal encoding of information at all levels, from the cell to the whole plant. Defining this patterning will be a critical step towards understanding how plants integrate information from multiple mechanical stimuli to an appropriate growth response.

  5. Plant-phytopathogen interactions: bacterial responses to environmental and plant stimuli.

    Science.gov (United States)

    Leonard, Simon; Hommais, Florence; Nasser, William; Reverchon, Sylvie

    2017-05-01

    Plant pathogenic bacteria attack numerous agricultural crops, causing devastating effects on plant productivity and yield. They survive in diverse environments, both in plants, as pathogens, and also outside their hosts as saprophytes. Hence, they are confronted with numerous changing environmental parameters. During infection, plant pathogens have to deal with stressful conditions, such as acidic, oxidative and osmotic stresses; anaerobiosis; plant defenses; and contact with antimicrobial compounds. These adverse conditions can reduce bacterial survival and compromise disease initiation and propagation. Successful bacterial plant pathogens must detect potential hosts and also coordinate their possibly conflicting programs for survival and virulence. Consequently, these bacteria have a strong and finely tuned capacity for sensing and responding to environmental and plant stimuli. This review summarizes our current knowledge of the signals and genetic circuits that affect survival and virulence factor expression in three important and well-studied plant pathogenic bacteria with wide host ranges and the capacity for long-term environmental survival. These are: Ralstonia solanacerarum, a vascular pathogen that causes wilt disease; Agrobacterium tumefaciens, a biotrophic tumorigenic pathogen responsible for crown gall disease and Dickeya, a brute force apoplastic pathogen responsible for soft-rot disease. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  6. CSIR eNews: Defence peace safety and security

    CSIR Research Space (South Africa)

    CSIR

    2009-08-01

    Full Text Available , peace, safety and security. CSIR Defence, Peace, Safety and Security provides a national defence S&T capability: supplying knowledge, advice and solutions in defence and matters of national security....

  7. Organ-specific defence strategies of pepper (Capsicum annuum L.) during early phase of water deficit.

    Science.gov (United States)

    Sziderics, Astrid Heide; Oufir, Mouhssin; Trognitz, Friederike; Kopecky, Dieter; Matusíková, Ildikó; Hausman, Jean-Francois; Wilhelm, Eva

    2010-03-01

    Drought is one of the major factors that limits crop production and reduces yield. To understand the early response of plants under nearly natural conditions, pepper plants (Capsicum annuum L.) were grown in a greenhouse and stressed by withholding water for 1 week. Plants adapted to the decreasing water content of the soil by adjustment of their osmotic potential in root tissue. As a consequence of drought, strong accumulation of raffinose, glucose, galactinol and proline was detected in the roots. In contrast, in leaves the levels of fructose, sucrose and also galactinol increased. Due to the water deficit cadaverine, putrescine, spermidine and spermine accumulated in leaves, whereas the concentration of polyamines was reduced in roots. To study the molecular basis of these responses, a combined approach of suppression subtractive hybridisation and microarray technique was performed on the same material. A total of 109 unique ESTs were detected as responsive to drought, while additional 286 ESTs were selected from the bulk of rare transcripts on the array. The metabolic profiles of stressed pepper plants are discussed with respect to the transcriptomic changes detected, while attention is given to the differences between defence strategies of roots and leaves.

  8. Plant surface wax affects parasitoid's response to host footprints

    Science.gov (United States)

    Rostás, Michael; Ruf, Daniel; Zabka, Vanessa; Hildebrandt, Ulrich

    2008-10-01

    The plant surface is the substrate upon which herbivorous insects and natural enemies meet and thus represents the stage for interactions between the three trophic levels. Plant surfaces are covered by an epicuticular wax layer which is highly variable depending on species, cultivar or plant part. Differences in wax chemistry may modulate ecological interactions. We explored whether caterpillars of Spodoptera frugiperda, when walking over a plant surface, leave a chemical trail (kairomones) that can be detected by the parasitoid Cotesia marginiventris. Chemistry and micromorphology of cuticular waxes of two barley eceriferum wax mutants ( cer-za.126, cer-yp.949) and wild-type cv. Bonus (wt) were assessed. The plants were then used to investigate potential surface effects on the detectability of caterpillar kairomones. Here we provide evidence that C. marginiventris responds to chemical footprints of its host. Parasitoids were able to detect the kairomone on wild-type plants and on both cer mutants but the response to cer-yp.949 (reduced wax, high aldehyde fraction) was less pronounced. Experiments with caterpillar-treated wt and mutant leaves offered simultaneously, confirmed this observation: no difference in wasp response was found when wt was tested against cer-za.126 (reduced wax, wt-like chemical composition) but wt was significantly more attractive than cer-yp.949. This demonstrates for the first time that the wax layer can modulate the detectability of host kairomones.

  9. Glutathione-dependent responses of plants to drought: a review

    Directory of Open Access Journals (Sweden)

    Mateusz Labudda

    2014-02-01

    Full Text Available Water is a renewable resource. However, with the human population growth, economic development and improved living standards, the world’s supply of fresh water is steadily decreasing and consequently water resources for agricultural production are limited and diminishing. Water deficiency is a significant problem in agriculture and increasing efforts are currently being made to understand plant tolerance mechanisms and to develop new tools (especially molecular that could underpin plant breeding and cultivation. However, the biochemical and molecular mechanisms of plant water deficit tolerance are not fully understood, and the data available is incomplete. Here, we review the significance of glutathione and its related enzymes in plant responses to drought. Firstly, the roles of reduced glutathione and reduced/oxidized glutathione ratio, are discussed, followed by an extensive discussion of glutathione related enzymes, which play an important role in plant responses to drought. Special attention is given to the S-glutathionylation of proteins, which is involved in cell metabolism regulation and redox signaling in photosynthetic organisms subjected to abiotic stress. The review concludes with a brief overview of future perspectives for the involvement of glutathione and related enzymes in drought stress responses.

  10. Plant community mediation of ecosystem responses to global change factors

    Science.gov (United States)

    Churchill, A. C.

    2017-12-01

    Human alteration of the numerous environmental drivers affecting ecosystem processes is unprecedented in the last century, including changes in climate regimes and rapid increases in the availability of biologically active nitrogen (N). Plant communities may offer stabilizing or amplifying feedbacks mediating potential ecosystem responses to these alterations, and my research seeks to examine the conditions associated with when plant feedbacks are important for ecosystem change. My dissertation research focused on the unintended consequences of N deposition into natural landscapes, including alpine ecosystems which are particularly susceptible to adverse environmental impacts. In particular, I examined alpine plant and soil responses to N deposition 1) across multiple spatial scales throughout the Southern Rocky Mountains, 2) among diverse plant communities associated with unique environmental conditions common in the alpine of this region, and 3) among ecosystem pools of N contributing to stabilization of N inputs within those communities. I found that communities responded to inputs of N differently, often associated with traits of dominant plant species but these responses were intimately linked with the abiotic conditions of each independent community. Even so, statistical models predicting metrics of N processing in the alpine were improved by encompassing both abiotic and biotic components of the main community types.

  11. The rare sugar D-allose acts as a triggering molecule of rice defence via ROS generation.

    Science.gov (United States)

    Kano, Akihito; Fukumoto, Takeshi; Ohtani, Kouhei; Yoshihara, Akihide; Ohara, Toshiaki; Tajima, Shigeyuki; Izumori, Ken; Tanaka, Keiji; Ohkouchi, Takeo; Ishida, Yutaka; Nishizawa, Yoko; Ichimura, Kazuya; Tada, Yasuomi; Gomi, Kenji; Akimitsu, Kazuya

    2013-11-01

    Only D-allose, among various rare monosaccharides tested, induced resistance to Xanthomonas oryzae pv. oryzae in susceptible rice leaves with defence responses: reactive oxygen species, lesion mimic formation, and PR-protein gene expression. These responses were suppressed by ascorbic acid or diphenylene iodonium. Transgenic rice plants overexpressing OsrbohC, encoding NADPH oxidase, were enhanced in sensitivity to D-allose. D-Allose-mediated defence responses were suppressed by the presence of a hexokinase inhibitor. 6-Deoxy-D-allose, a structural derivative of D-allose unable to be phosphorylated, did not confer resistance. Transgenic rice plants expressing Escherichia coli AlsK encoding D-allose kinase to increase D-allose 6-phosphate synthesis were more sensitive to D-allose, but E. coli AlsI encoding D-allose 6-phosphate isomerase expression to decrease D-allose 6-phosphate reduced sensitivity. A D-glucose 6-phosphate dehydrogenase-defective mutant was also less sensitive, and OsG6PDH1 complementation restored full sensitivity. These results reveal that a monosaccharide, D-allose, induces rice resistance to X. oryzae pv. oryzae by activating NADPH oxidase through the activity of D-glucose 6-phosphate dehydrogenase, initiated by hexokinase-mediated conversion of D-allose to D-allose 6-phosphate, and treatment with D-allose might prove to be useful for reducing disease development in rice.

  12. Defence electro-optics: European perspective

    Science.gov (United States)

    Hartikainen, Jari

    2011-11-01

    In 2009 the United States invested in defence R&T 3,6 times and in defence research and development 6,8 times as much as all member states of the European Defence Agency (EDA) combined while the ratio in the total defence expenditure was 2,6 in the US' favour. The European lack of investments in defence research and development has a negative impact on the competitiveness of European defence industry and on the European non-dependence. In addition, the efficiency of investment is reduced due to duplication of work in different member states. The Lisbon Treaty tasks EDA to support defence technology research, and coordinate and plan joint research activities and the study of technical solutions meeting future operational needs. This paper gives an overview how EDA meets the challenge of improving the efficiency of European defence R&T investment with an emphasis on electro-optics and describes shortly the ways that governmental and industrial partners can participate in the EDA cooperation. Examples of joint R&T projects addressing electro-optics are presented.

  13. Defence counsel in international criminal law

    NARCIS (Netherlands)

    Temminck Tuinstra, J.P.W.

    2009-01-01

    The field of international criminal law is relatively new and rapidly developing. This dissertation examines whether international criminal courts enable defence counsel to conduct an effective defence. When the International Criminal Tribunals for the former Yugoslavia and Rwanda (the ad hoc

  14. The South African National Defence Force

    DEFF Research Database (Denmark)

    Mandrup, Thomas

    2009-01-01

    This research paper is an evaluation of The Souch African National Defence Force´s (SANDF) involvement in Peace Support Operations.......This research paper is an evaluation of The Souch African National Defence Force´s (SANDF) involvement in Peace Support Operations....

  15. Jasmonate-responsive transcription factors regulating plant secondary metabolism.

    Science.gov (United States)

    Zhou, Meiliang; Memelink, Johan

    2016-01-01

    Plants produce a large variety of secondary metabolites including alkaloids, glucosinolates, terpenoids and phenylpropanoids. These compounds play key roles in plant-environment interactions and many of them have pharmacological activity in humans. Jasmonates (JAs) are plant hormones which induce biosynthesis of many secondary metabolites. JAs-responsive transcription factors (TFs) that regulate the JAs-induced accumulation of secondary metabolites belong to different families including AP2/ERF, bHLH, MYB and WRKY. Here, we give an overview of the types and functions of TFs that have been identified in JAs-induced secondary metabolite biosynthesis, and highlight their similarities and differences in regulating various biosynthetic pathways. We review major recent developments regarding JAs-responsive TFs mediating secondary metabolite biosynthesis, and provide suggestions for further studies. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Physiological blockage in plants in response to postharvest stress

    African Journals Online (AJOL)

    Marcos

    2013-03-13

    Mar 13, 2013 ... response of the plant to cut stem (Ichimura et al., 1999). When the vessel is blocked, ... E-mail: m.r.s.v@hotmail.com. of complex physiological ... of cells which protrude into the vessel lumen xylem whose shape is similar to a.

  17. Physiological blockage in plants in response to postharvest stress

    African Journals Online (AJOL)

    Marcos

    2013-03-13

    Mar 13, 2013 ... response of the plant to cut stem (Ichimura et al., 1999). When the vessel is ... blockage due to microbial growth and blockage caused by formation of .... HQS) and chlorine, are used to assess its actions in the microorganisms ...

  18. Responses of soilless grown tomato plants to arbuscular ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-10-20

    Oct 20, 2008 ... Full Length Research Paper. Responses of soilless grown tomato plants to arbuscular mycorrhizal fungal (Glomus fasciculatum) colonization in re-cycling and open systems. H. Yildiz Dasgan1*, Sebnem Kusvuran1 and Ibrahim Ortas2. 1Cukurova University, Faculty of Agriculture, Department of Horticulture ...

  19. Green thermoelectrics: Observation and analysis of plant thermoelectric response

    Directory of Open Access Journals (Sweden)

    Goupil Christophe

    2016-01-01

    Full Text Available Plants are sensitive to thermal and electrical effects; yet the coupling of both, known as thermoelectricity, and its quantitative measurement in vegetal systems never were reported. We recorded the thermoelectric response of bean sprouts under various thermal conditions and stress. The obtained experimental data unambiguously demonstrate that a temperature difference between the roots and the leaves of a bean sprout induces a thermoelectric voltage between these two points. Basing our analysis of the data on the force-flux formalism of linear response theory, we found that the strength of the vegetal equivalent to the thermoelectric coupling is one order of magnitude larger than that in the best thermoelectric materials. Experimental data also show the importance of the thermal stress variation rate in the plant’s electrophysiological response. therefore, thermoelectric effects are sufficiently important to partake in the complex and intertwined processes of energy and matter transport within plants.

  20. Unraveling plant responses to bacterial pathogens through proteomics

    KAUST Repository

    Zimaro, Tamara

    2011-11-03

    Plant pathogenic bacteria cause diseases in important crops and seriously and negatively impact agricultural production. Therefore, an understanding of the mechanisms by which plants resist bacterial infection at the stage of the basal immune response or mount a successful specific R-dependent defense response is crucial since a better understanding of the biochemical and cellular mechanisms underlying these interactions will enable molecular and transgenic approaches to crops with increased biotic resistance. In recent years, proteomics has been used to gain in-depth understanding of many aspects of the host defense against pathogens and has allowed monitoring differences in abundance of proteins as well as posttranscriptional and posttranslational processes, protein activation/inactivation, and turnover. Proteomics also offers a window to study protein trafficking and routes of communication between organelles. Here, we summarize and discuss current progress in proteomics of the basal and specific host defense responses elicited by bacterial pathogens. Copyright 2011 Tamara Zimaro et al.

  1. Unraveling plant responses to bacterial pathogens through proteomics

    KAUST Repository

    Zimaro, Tamara; Gottig, Natalia; Garavaglia, Betiana S.; Gehring, Christoph A; Ottado, Jorgelina

    2011-01-01

    Plant pathogenic bacteria cause diseases in important crops and seriously and negatively impact agricultural production. Therefore, an understanding of the mechanisms by which plants resist bacterial infection at the stage of the basal immune response or mount a successful specific R-dependent defense response is crucial since a better understanding of the biochemical and cellular mechanisms underlying these interactions will enable molecular and transgenic approaches to crops with increased biotic resistance. In recent years, proteomics has been used to gain in-depth understanding of many aspects of the host defense against pathogens and has allowed monitoring differences in abundance of proteins as well as posttranscriptional and posttranslational processes, protein activation/inactivation, and turnover. Proteomics also offers a window to study protein trafficking and routes of communication between organelles. Here, we summarize and discuss current progress in proteomics of the basal and specific host defense responses elicited by bacterial pathogens. Copyright 2011 Tamara Zimaro et al.

  2. Understanding the Posttranscriptional Regulation of Plant Responses to Abiotic Stress

    KAUST Repository

    AlShareef, Sahar A.

    2017-06-01

    Constitutive and alternative splicing of pre-mRNAs from multiexonic genes controls the diversity of the proteome; these precisely regulated processes also fine-tune responses to cues related to growth, development, and biotic and abiotic stresses. Recent work showed that AS is pervasive across plant species, with more than 60% of intron-containing genes producing different isoforms. Mammalian cell-based assays have discovered various AS small-molecule inhibitors that perturb splicing and thereby provide invaluable tools for use as chemical probes to uncover the molecular underpinnings of splicing regulation and as potential anticancer compounds. Here, I show that the macrolide Pladienolide B (PB) and herboxidiene (GEX1A) inhibits both constitutive and alternative splicing, mimics an abiotic stress signal, and activates the abscisic acid (ABA) pathway in plants. Moreover, PB and GEX1A activate genome-wide transcriptional patterns involved in abiotic stress responses in plants. PB and GEX1A treatment triggered the ABA signaling pathway, activated ABA-inducible promoters, and led to stomatal closure. Interestingly, PB and GEX1A elicited similar cellular changes, including alterations in the patterns of transcription and splicing, suggesting that these compounds might target the same spliceosome complex in plant cells. This work establishes PB and GEX1A as potent splicing inhibitors in plants that can be used to probe the assembly, dynamics, and molecular functions of the spliceosome and to study the interplay between splicing stress and abiotic stresses, as well as having potential biotechnological applications.

  3. Assessing Cd-induced stress from plant spectral response

    Science.gov (United States)

    Kancheva, Rumiana; Georgiev, Georgi

    2014-10-01

    Remote sensing plays a significant role in local, regional and global monitoring of land covers. Ecological concerns worldwide determine the importance of remote sensing applications for the assessment of soil conditions, vegetation health and identification of stress-induced changes. The extensive industrial growth and intensive agricultural land-use arise the serious ecological problem of environmental pollution associated with the increasing anthropogenic pressure on the environment. Soil contamination is a reason for degradation processes and temporary or permanent decrease of the productive capacity of land. Heavy metals are among the most dangerous pollutants because of their toxicity, persistent nature, easy up-take by plants and long biological half-life. This paper takes as its focus the study of crop species spectral response to Cd pollution. Ground-based experiments were performed, using alfalfa, spring barley and pea grown in Cd contaminated soils and in different hydroponic systems under varying concentrations of the heavy metal. Cd toxicity manifested itself by inhibition of plant growth and synthesis of photosynthetic pigments. Multispectral reflectance, absorbance and transmittance, as well as red and far red fluorescence were measured and examined for their suitability to detect differences in plant condition. Statistical analysis was performed and empirical relationships were established between Cd concentration, plant growth variables and spectral response Various spectral properties proved to be indicators of plant performance and quantitative estimators of the degree of the Cd-induced stress.

  4. Testing for the induction of anti-herbivory defences in four Portuguese macroalgae by direct and water-borne cues of grazing amphipods

    OpenAIRE

    Yun, H. Y.; Cruz, J.; Treitschke, M.; Wahl, Martin; Molis, M.

    2007-01-01

    Herbivory is a key factor in regulating plant biomass, thereby driving ecosystem performance. Algae have developed multiple adaptations to cope with grazers, including morphological and chemical defences. In a series of experiments we investigated whether several species of macroalgae possess anti-herbivore defences and whether these could be regulated to demand, i.e. grazing events. The potential of direct grazing on defence induction was assessed for two brown (Dictyopteris membranacea, Fuc...

  5. KYPO – A Platform for Cyber Defence Exercises

    OpenAIRE

    Čeleda Pavel; Čegan Jakub; Vykopal Jan; Tovarňák Daniel

    2015-01-01

    Correct and timely responses to cyber attacks are crucial for the effective implementation of cyber defence strategies and policies. The number of threats and ingenuity of attackers is ever growing, as is the need for more advanced detection tools, techniques and skilled cyber security professionals. KYPO – Cyber Exercise & Research Platform is focused on modelling and simulating complex computer systems and networks in a virtualized and separated environment. The platform enables realist...

  6. Revealing the importance of meristems and roots for the development of hypersensitive responses and full foliar resistance to Phytophthora infestans in the resistant potato cultivar Sarpo Mira

    DEFF Research Database (Denmark)

    Orlowska, Elzbieta Zofia; Basile, Alessio; Kandzia, Izabela

    2012-01-01

    The defence responses of potato against Phytophthora infestans were studied using the highly resistant Sarpo Mira cultivar. The effects of plant integrity, meristems, and roots on the hypersensitive response (HR), plant resistance, and the regulation of PR genes were analysed. Sarpo Mira shoots a...

  7. Physiological and biochemical responses of thyme plants to some antioxidants

    Directory of Open Access Journals (Sweden)

    SALWA A. ORABI

    2014-11-01

    Full Text Available Orabi SA, Talaat IM, Balbaa LK. 2014. Physiological and biochemical responses of thyme plants to some antioxidants. Nusantara Bioscience 6: 118-125. Two pot experiments were conducted to investigate the effect of tryptophan, nicotinamide and α-tocopherol (each at 50 and 100 mg/L on plant growth, essential oil yield and its main constituents. All treatments significantly promoted plant height, and increased fresh and dry mass (g/plant of thyme (Thymus vulgaris L.. The treatment with 100 mg/L nicotinamide showed increasing in total potassium mainly in the first cut. Total soluble sugars, oil percentage and oil yield and protein recorded increments with tryptophan treatments. Treatment of Thymus plants with 100 mg/L nicotinamide observed the highest percentage of thymol (67.61%. Oxygenated compounds recorded the highest value with 50 mg/L α-tocopherol treatment, while the maximum non-oxygenated ones resulted from the application of 100 mg/L nicotinamide. All treatments under study significantly affected the activity of oxidoreductase enzymes (POX and PPO. Nicotinamide at the concentration of 100 mg/L recorded the highest increments in APX and GR and the lowest values in oxidoreductase enzyme activities added to the lowest values of lipid peroxidation to enhance the best protection of thyme plants.

  8. Seismic response analysis for a deeply embedded nuclear power plant

    International Nuclear Information System (INIS)

    Chen, W.W.H.; Chatterjee, M.; Day, S.M.

    1979-01-01

    One of the important aspect of the aseimic design of nuclear power plants is the evaluation of the seismic soil-structure interaction effect due to design earthquakes. The soil-structure interaction effect can initiate rocking and result in different soil motions compared to the free field motions, thus significantly affecting the structural response. Two methods are generally used to solve the seismic soil-structure interaction problems: the direct finite element method (FLUSH) and the substructure or impedance approach. This paper presents the results of the horizontal seismic soil-structure interaction analysis using the impedance aproach and the direct finite element method for a deeply embedded nuclear power plant. (orig.)

  9. Response of plant species to coal-mine soil materials

    Energy Technology Data Exchange (ETDEWEB)

    Day, A.D.; Tucker, T.C.; Thames, J.L.

    1983-03-01

    The two-year Black Mesa Coal Mine Research Study on the area near Kayenta, Arizona investigating the growth and establishment of seven plant species in unmined soil and coal-mined soils found that plant species grew better in unmined soil and that irrigation is essential during seedling establishment for the effective stabilization of coal-mined soils in a semi-arid environment. Differences among the species included variations in germination, response to irrigation, seedling establishment, and stem growth. 12 references, 2 figures, 2 tables.

  10. Biochemical response and host-pathogen relation of stalk rot fungi ...

    African Journals Online (AJOL)

    Dr. nirupma

    photosynthesis, which are the vital processes taking place inside the plant, leading to wide fluctuations in sugars (Klement ... The suspension spray was prepared by taking. 200 ml of ..... biochemical factors due to cell response that is, defence .... by Fusarium moniliforme on corn growth and cellular morphology. Plant Dis.

  11. Plant Nucleolar Stress Response, a New Face in the NAC-Dependent Cellular Stress Responses.

    Science.gov (United States)

    Ohbayashi, Iwai; Sugiyama, Munetaka

    2017-01-01

    The nucleolus is the most prominent nuclear domain, where the core processes of ribosome biogenesis occur vigorously. All these processes are finely orchestrated by many nucleolar factors to build precisely ribosome particles. In animal cells, perturbations of ribosome biogenesis, mostly accompanied by structural disorders of the nucleolus, cause a kind of cellular stress to induce cell cycle arrest, senescence, or apoptosis, which is called nucleolar stress response. The best-characterized pathway of this stress response involves p53 and MDM2 as key players. p53 is a crucial transcription factor that functions in response to not only nucleolar stress but also other cellular stresses such as DNA damage stress. These cellular stresses release p53 from the inhibition by MDM2, an E3 ubiquitin ligase targeting p53, in various ways, which leads to p53-dependent activation of a set of genes. In plants, genetic impairments of ribosome biogenesis factors or ribosome components have been shown to cause characteristic phenotypes, including a narrow and pointed leaf shape, implying a common signaling pathway connecting ribosomal perturbations and certain aspects of growth and development. Unlike animals, however, plants have neither p53 nor MDM2 family proteins. Then the question arises whether plant cells have a nucleolar stress response pathway. In recent years, it has been reported that several members of the plant-specific transcription factor family NAC play critical roles in the pathways responsive to various cellular stresses. In this mini review, we outline the plant cellular stress response pathways involving NAC transcription factors with reference to the p53-MDM2-dependent pathways of animal cells, and discuss the possible involvement of a plant-unique, NAC-mediated pathway in the nucleolar stress response in plants.

  12. Plant Nucleolar Stress Response, a New Face in the NAC-Dependent Cellular Stress Responses

    Directory of Open Access Journals (Sweden)

    Iwai Ohbayashi

    2018-01-01

    Full Text Available The nucleolus is the most prominent nuclear domain, where the core processes of ribosome biogenesis occur vigorously. All these processes are finely orchestrated by many nucleolar factors to build precisely ribosome particles. In animal cells, perturbations of ribosome biogenesis, mostly accompanied by structural disorders of the nucleolus, cause a kind of cellular stress to induce cell cycle arrest, senescence, or apoptosis, which is called nucleolar stress response. The best-characterized pathway of this stress response involves p53 and MDM2 as key players. p53 is a crucial transcription factor that functions in response to not only nucleolar stress but also other cellular stresses such as DNA damage stress. These cellular stresses release p53 from the inhibition by MDM2, an E3 ubiquitin ligase targeting p53, in various ways, which leads to p53-dependent activation of a set of genes. In plants, genetic impairments of ribosome biogenesis factors or ribosome components have been shown to cause characteristic phenotypes, including a narrow and pointed leaf shape, implying a common signaling pathway connecting ribosomal perturbations and certain aspects of growth and development. Unlike animals, however, plants have neither p53 nor MDM2 family proteins. Then the question arises whether plant cells have a nucleolar stress response pathway. In recent years, it has been reported that several members of the plant-specific transcription factor family NAC play critical roles in the pathways responsive to various cellular stresses. In this mini review, we outline the plant cellular stress response pathways involving NAC transcription factors with reference to the p53-MDM2-dependent pathways of animal cells, and discuss the possible involvement of a plant-unique, NAC-mediated pathway in the nucleolar stress response in plants.

  13. Plant genetic and molecular responses to water deficit

    Directory of Open Access Journals (Sweden)

    Silvio Salvi

    2011-02-01

    Full Text Available Plant productivity is severely affected by unfavourable environmental conditions (biotic and abiotic stresses. Among others, water deficit is the plant stress condition which mostly limits the quality and the quantity of plant products. Tolerance to water deficit is a polygenic trait strictly dependent on the coordinated expression of a large set of genes coding for proteins directly involved in stress-induced protection/repair mechanisms (dehydrins, chaperonins, enzymes for the synthesis of osmoprotectants and detoxifying compounds, and others as well as genes involved in transducing the stress signal and regulating gene expression (transcription factors, kinases, phosphatases. Recently, research activities in the field evolved from the study of single genes directly involved in cellular stress tolerance (functional genes to the identification and characterization of key regulatory genes involved in stress perception and transduction and able to rapidly and efficiently activate the complex gene network involved in the response to stress. The complexity of the events occurring in response to stress have been recently approached by genomics tools; in fact the analysis of transcriptome, proteome and metabolome of a plant tissue/cell in response to stress already allowed to have a global view of the cellular and molecular events occurring in response to water deficit, by the identification of genes activated and co-regulated by the stress conditions and the characterization of new signalling pathways. Moreover the recent application of forward and reverse genetic approaches, trough mutant collection development, screening and characterization, is giving a tremendous impulse to the identification of gene functions with key role in stress tolerance. The integration of data obtained by high-throughput genomic approaches, by means of powerful informatic tools, is allowing nowadays to rapidly identify of major genes/QTLs involved in stress tolerance

  14. Nanosecond electric pulses trigger actin responses in plant cells

    International Nuclear Information System (INIS)

    Berghoefer, Thomas; Eing, Christian; Flickinger, Bianca; Hohenberger, Petra; Wegner, Lars H.; Frey, Wolfgang; Nick, Peter

    2009-01-01

    We have analyzed the cellular effects of nanosecond pulsed electrical fields on plant cells using fluorescently tagged marker lines in the tobacco cell line BY-2 and confocal laser scanning microscopy. We observe a disintegration of the cytoskeleton in the cell cortex, followed by contraction of actin filaments towards the nucleus, and disintegration of the nuclear envelope. These responses are accompanied by irreversible permeabilization of the plasma membrane manifest as uptake of Trypan Blue. By pretreatment with the actin-stabilizing drug phalloidin, the detachment of transvacuolar actin from the cell periphery can be suppressed, and this treatment can also suppress the irreversible perforation of the plasma membrane. We discuss these findings in terms of a model, where nanosecond pulsed electric fields trigger actin responses that are key events in the plant-specific form of programmed cell death.

  15. NRT/PTR transporters are essential for translocation of glucosinolate defence compounds to seeds

    DEFF Research Database (Denmark)

    Nour-Eldin, Hussam Hassan; Andersen, Tonni Grube; Burow, Meike

    2012-01-01

    glucosinolates in seeds and had more than tenfold over-accumulation in source tissues such as leaves and silique walls, indicating that both plasma membrane-localized transporters are essential for long-distance transport of glucosinolates. We propose that GTR1 and GTR2 control the loading of glucosinolates from......In plants, transport processes are important for the reallocation of defence compounds to protect tissues of high value, as demonstrated in the plant model Arabidopsis, in which the major defence compounds, glucosinolates, are translocated to seeds on maturation. The molecular basis for long...

  16. Defence in Depth: Assessment of Comprehensiveness and Further Strengthening of the Concept

    Energy Technology Data Exchange (ETDEWEB)

    Misak, J., E-mail: Jozef.Misak@ujv.cz

    2014-10-15

    Full text: Defence in depth concept based on multiple levels of protection of the workers, public and the environment against radiation harm is and should remain an essential strategy for ensuring safety of nuclear power plants. This strategy should be comprehensively implemented through all stages of the plant lifetime, from the siting through construction and operation up to decommissioning. First part of the presentation will introduce a screening method developed by the IAEA as a tool facilitating the assessment of the comprehensiveness of defence in depth and will indicate further possibilities for using and updating the approach by taking into account recent lessons learned. Although it is clear that it is not possible for any industrial facility including nuclear power plants to fully eliminate the risk, further strengthening the defence in depth in particular at level 4 dealing with design extension conditions gives very high confidence in prevention and effective mitigation of severe accidents so that they are either practically eliminated or their consequences are limited in area and time. Second part of the presentation will discuss several issues associated with current efforts for strengthening the defence in depth, including the issues of practical elimination, independence and diversity of safety provisions at different levels of defence. (author)

  17. Unique phytochrome responses of the holoparasitic plant Orobanche minor.

    Science.gov (United States)

    Takagi, Kazuteru; Okazawa, Atsushi; Wada, Yu; Mongkolchaiyaphruek, Anchaya; Fukusaki, Eiichiro; Yoneyama, Koichi; Takeuchi, Yasutomo; Kobayashi, Akio

    2009-06-01

    Holoparasitic plants such as Orobanche spp. have lost their photosynthetic ability, so photoresponses to optimize photosynthesis are not necessary in these plants. Photoresponses are also involved in the regulation of plant development but the photoresponses of holoparasites have not been characterized in detail. In this study, the phytochrome (phy)-related photoresponse of Orobanche minor was investigated. Its photoreceptor, phytochrome A (OmphyA), was also characterized. Light effects on germination, shoot elongation, anthocyanin biosynthesis, and OmphyA expression and subcellular localization were analyzed. Red light (R):far-red light (FR) reversible inhibition of O. minor seed germination demonstrated that phy-mediated responses are retained in this holoparasite. Shoot elongation was inhibited by FR but not by R. This pattern is unique among known patterns of plant photoresponses. Additionally, molecular analysis showed that OmphyA is able to respond to the light signals. Interestingly, the unique pattern of photoresponses in O. minor seems to have been modified for adaptation to its parasitic life cycle. We hypothesize that this alteration has resulted from the loss or alteration of some phy-signaling components. Elucidation of altered components in phy signaling in this parasite will provide useful information not only about its physiological characteristics but also about general plant photoreception systems.

  18. The Venturia Apple Pathosystem: Pathogenicity Mechanisms and Plant Defense Responses

    Directory of Open Access Journals (Sweden)

    Gopaljee Jha

    2009-01-01

    Full Text Available Venturia inaequalis is the causal agent of apple scab, a devastating disease of apple. We outline several unique features of this pathogen which are useful for molecular genetics studies intended to understand plant-pathogen interactions. The pathogenicity mechanisms of the pathogen and overview of apple defense responses, monogenic and polygenic resistance, and their utilization in scab resistance breeding programs are also reviewed.

  19. Effectors from Wheat Rust Fungi Suppress Multiple Plant Defense Responses.

    Science.gov (United States)

    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 (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.

  20. Unraveling the response of plant cells to cytotoxic saponins

    Science.gov (United States)

    Balestrazzi, Alma; Macovei, Anca; Tava, Aldo; Avato, Pinarosa; Raimondi, Elena

    2011-01-01

    A wide range of pharmacological properties are ascribed to natural saponins, in addition to their biological activities against herbivores, plant soil-borne pathogens and pests. As for animal cells, the cytotoxicity and the chemopreventive role of saponins are mediated by a complex network of signal transduction pathways which include reactive oxygen species (ROS) and nitric oxide (NO). The involvement of other relevant components of the saponin-related signaling routes, such as the Tumor Necrosis Factor (TNF)α, the interleukin (IL)-6 and the Nuclear Transcription FactorκB (NFκB), has been highlighted in animal cells. By contrast, information concerning the response of plant cells to saponins and the related signal transduction pathways is almost missing. To date, there are only a few common features which link plant and animal cells in their response to saponins, such as the early burst in ROS and NO production and the induction of metallothioneins (MTs), small cysteine-rich, metal-binding proteins. This aspect is discussed in the present paper in view of the recent hypothesis that MTs and NO are part of a novel signal transduction pathway participating in the cell response to oxidative stress. PMID:21673512

  1. Grapevine fatty acid hydroperoxide lyase generates actin-disrupting volatiles and promotes defence-related cell death

    Science.gov (United States)

    Wang, Hao; Claudel, Patricia; Riemann, Michael; Hause, Bettina; Hugueney, Philippe; Nick, Peter

    2018-01-01

    Abstract Fatty acid hydroperoxides can generate short-chained volatile aldehydes that may participate in plant defence. A grapevine hydroperoxide lyase (VvHPL1) clustering to the CYP74B class was functionally characterized with respect to a role in defence. In grapevine leaves, transcripts of this gene accumulated rapidly to high abundance in response to wounding. Cellular functions of VvHPL1 were investigated upon heterologous expression in tobacco BY-2 cells. A C-terminal green fluorescent protein (GFP) fusion of VvHPL1 was located in plastids. The overexpression lines were found to respond to salinity stress or the bacterial elicitor harpin by increasing cell death. This signal-dependent mortality response was mitigated either by addition of exogenous jasmonic acid or by treatment with diphenyleneiodonium (DPI), an inhibitor of NADPH oxidases. By feeding different substrates to recombinantly expressed enzyme, VvHPL1 could also be functionally classified as true 13-HPL. The cognate products generated by this 13-HPL were cis-3-hexenal and trans-2-hexenal. Using a GFP-tagged actin marker line, one of these isomeric products, cis-3-hexenal, was found specifically to elicit a rapid disintegration of actin filaments. This response was not only observed in the heterologous system (tobacco BY-2), but also in a grapevine cell strain expressing this marker, as well as in leaf discs from an actin marker grape used as a homologous system. These results are discussed in the context of a role for VvHPL1 in a lipoxygenase-dependent signalling pathway triggering cell death-related defence that bifurcates from jasmonate-dependent basal immunity. PMID:29659985

  2. Antioxidant defences of Norway spruce bark against bark beetles and its associated blue-stain fungus

    Directory of Open Access Journals (Sweden)

    Felicijan Mateja

    2015-12-01

    Full Text Available Bark beetles and their fungal associates are integral parts of forest ecosystems, the European spruce bark beetle (Ips typographus Linnaeus, 1758 and the associated pathogenic blue stain fungus Ceratocystis polonica (SIEM. C. MOREAU, are the most devastating pests regarding Norway spruce [Picea abies (L. H. KARST.]. Bark beetles commonly inhabit weakened and felled trees as well as vital trees. They cause physiological disorders in trees by destroying a phloem and cambium or interrupt the transpiration -ow in the xylem. Conifers have a wide range of effective defence mechanisms that are based on the inner bark anatomy and physiological state of the tree. The basic function of bark defences is to protect the nutrient-and energy-rich phloem, the vital meristematic region of the vascular cambium, and the transpiration -ow in the sapwood. The main area of defence mechanisms is secondary phloem, which is physically and chemically protected by polyphenolic parenchyma (PP cells, sclerenchyma, calcium oxalate crystals and resin ducts. Conifer trunk pest resistance includes constitutive, inducible defences and acquired resistance. Both constitutive and inducible defences may deter beetle invasion, impede fungal growth and close entrance wounds. During a successful attack, systemic acquired resistance (SAR becomes effective and represents a third defence strategy. It gradually develops throughout the plant and provides a systemic change within the whole tree’s metabolism, which is maintained over a longer period of time. The broad range of defence mechanisms that contribute to the activation and utilisation of SAR, includes antioxidants and antioxidant enzymes, which are generally linked to the actions of reactive oxygen species (ROS. The presented review discusses the current knowledge on the antioxidant defence strategies of spruce inner bark against the bark beetle (Ips typographus and associated blue stain fungus (Ceratocystis polonica.

  3. Radiation accidents and defence of population

    International Nuclear Information System (INIS)

    Memmedov, A.M.

    2002-01-01

    Full text: Development of nuclear physics, the fundamental and the applied researches in the field of radioactive insured wide possibility for application of radionuclides and ionizing radiation source in the different fields of national economy. Application of radionuclides in chemical, metallurgical, food industry, in agriculture and etc. Fields provide a large economic profit. It's hard to apprise significance of ionizing radiation source using in medicine for diagnostics and treatment of different disease. Nuclear power engineering and nuclear industry are developing intensively. At same time nuclear power, ionizing radiation sources incur potential treat for surroundings and health of population. As even that stage of protective measure development: there is no possibility of that happening of radiation accidents. A radiation accident qualifies as loss of ionizing radiation sources direction, which provoked by disrepair equipment, natural calamity or other causes which could bring to unplanned irradiation of population or radioactive pollution of surroundings. At present some following typical cases connected with radiation accident have been chosen: Contentious using or keeping of ionizing radiation source with breach of established requires; Loss, theft of ionizing radiation sources or radiation plants, instruments; Leaving the sources of ionizing radiation in the holes; Refusal radiation technic exploited in industry, medicine, SRI and etc; Disrepair in nuclear transport means of conveyance; Crashes and accidents at NPP and at other enterprises of nuclear industry. The radiation accidents according to character, degree and scales have been divided into two groups: Radiation accidents not connected with NPP; Accidents in the nuclear engineering and industry; The radiation accidents not connected with NPP according their consequence divide into 5 groups; accidents which do not come to irradiation of personal, persons from population (more PN-permissible norm

  4. Altruistic defence behaviours in aphids

    Directory of Open Access Journals (Sweden)

    Brodeur Jacques

    2010-01-01

    Full Text Available Abstract Background Altruistic anti-predatory behaviours pose an evolutionary problem because they are costly to the actor and beneficial to the recipients. Altruistic behaviours can evolve through indirect fitness benefits when directed toward kin. The altruistic nature of anti-predatory behaviours is often difficult to establish because the actor can obtain direct fitness benefits, or the behaviour could result from selfish coercion by others, especially in eusocial animals. Non-eusocial parthenogenetically reproducing aphids form colonies of clone-mates, which are ideal to test the altruistic nature of anti-predatory defence behaviours. Many aphids release cornicle secretions when attacked by natural enemies such as parasitoids. These secretions contain an alarm pheromone that alerts neighbours (clone-mates of danger, thereby providing indirect fitness benefits to the actor. However, contact with cornicle secretions also hampers an attacker and could provide direct fitness to the actor. Results We tested the hypothesis that cornicle secretions are altruistic by assessing direct and indirect fitness consequences of smearing cornicle secretions onto an attacker, and by manipulating the number of clone-mates that could benefit from the behaviour. We observed parasitoids, Aphidius rhopalosiphi, foraging singly in patches of the cereal aphid Sitobion avenae of varied patch size (2, 6, and 12 aphids. Aphids that smeared parasitoids did not benefit from a reduced probability of parasitism, or increase the parasitoids' handling time. Smeared parasitoids, however, spent proportionately more time grooming and less time foraging, which resulted in a decreased host-encounter and oviposition rate within the host patch. In addition, individual smearing rate increased with the number of clone-mates in the colony. Conclusions Cornicle secretions of aphids were altruistic against parasitoids, as they provided no direct fitness benefits to secretion

  5. Cathelicidin-like helminth defence molecules (HDMs: absence of cytotoxic, anti-microbial and anti-protozoan activities imply a specific adaptation to immune modulation.

    Directory of Open Access Journals (Sweden)

    Karine Thivierge

    Full Text Available Host defence peptides (HDPs are expressed throughout the animal and plant kingdoms. They have multifunctional roles in the defence against infectious agents of mammals, possessing both bactericidal and immune-modulatory activities. We have identified a novel family of molecules secreted by helminth parasites (helminth defence molecules; HDMs that exhibit similar structural and biochemical characteristics to the HDPs. Here, we have analyzed the functional activities of four HDMs derived from Schistosoma mansoni and Fasciola hepatica and compared them to human, mouse, bovine and sheep HDPs. Unlike the mammalian HDPs the helminth-derived HDMs show no antimicrobial activity and are non-cytotoxic to mammalian cells (macrophages and red blood cells. However, both the mammalian- and helminth-derived peptides suppress the activation of macrophages by microbial stimuli and alter the response of B cells to cytokine stimulation. Therefore, we hypothesise that HDMs represent a novel family of HDPs that evolved to regulate the immune responses of their mammalian hosts by retaining potent immune modulatory properties without causing deleterious cytotoxic effects.

  6. Neonicotinoid insecticides induce salicylate-associated plant defense responses

    Science.gov (United States)

    Ford, Kevin A.; Casida, John E.; Chandran, Divya; Gulevich, Alexander G.; Okrent, Rachel A.; Durkin, Kathleen A.; Sarpong, Richmond; Bunnelle, Eric M.; Wildermuth, Mary C.

    2010-01-01

    Neonicotinoid insecticides control crop pests based on their action as agonists at the insect nicotinic acetylcholine receptor, which accepts chloropyridinyl- and chlorothiazolyl-analogs almost equally well. In some cases, these compounds have also been reported to enhance plant vigor and (a)biotic stress tolerance, independent of their insecticidal function. However, this mode of action has not been defined. Using Arabidopsis thaliana, we show that the neonicotinoid compounds, imidacloprid (IMI) and clothianidin (CLO), via their 6-chloropyridinyl-3-carboxylic acid and 2-chlorothiazolyl-5-carboxylic acid metabolites, respectively, induce salicylic acid (SA)-associated plant responses. SA is a phytohormone best known for its role in plant defense against pathogens and as an inducer of systemic acquired resistance; however, it can also modulate abiotic stress responses. These neonicotinoids effect a similar global transcriptional response to that of SA, including genes involved in (a)biotic stress response. Furthermore, similar to SA, IMI and CLO induce systemic acquired resistance, resulting in reduced growth of a powdery mildew pathogen. The action of CLO induces the endogenous synthesis of SA via the SA biosynthetic enzyme ICS1, with ICS1 required for CLO-induced accumulation of SA, expression of the SA marker PR1, and fully enhanced resistance to powdery mildew. In contrast, the action of IMI does not induce endogenous synthesis of SA. Instead, IMI is further bioactivated to 6-chloro-2-hydroxypyridinyl-3-carboxylic acid, which is shown here to be a potent inducer of PR1 and inhibitor of SA-sensitive enzymes. Thus, via different mechanisms, these chloropyridinyl- and chlorothiazolyl-neonicotinoids induce SA responses associated with enhanced stress tolerance. PMID:20876120

  7. De Nederlandse missile defence capaciteit: Strategisch onmisbaar

    NARCIS (Netherlands)

    Weimar, P.W.L.

    2013-01-01

    Surface based air & missile defence behelst enerzijds de verdediging tegen conventionele luchtdreigingen, zoals vliegtuigen, helikopters en onbemande vliegtuigen (luchtverdediging). Aan de andere kant houdt het de verdediging tegen ballistische raketten en kruisraketten in (raketverdediging). De

  8. RNA-Binding Proteins in Plant Immunity

    Directory of Open Access Journals (Sweden)

    Virginia Woloshen

    2011-01-01

    Full Text Available Plant defence responses against pathogen infection are crucial to plant survival. The high degree of regulation of plant immunity occurs both transcriptionally and posttranscriptionally. Once transcribed, target gene RNA must be processed prior to translation. This includes polyadenylation, 5′capping, editing, splicing, and mRNA export. RNA-binding proteins (RBPs have been implicated at each level of RNA processing. Previous research has primarily focused on structural RNA-binding proteins of yeast and mammals; however, more recent work has characterized a number of plant RBPs and revealed their roles in plant immune responses. This paper provides an update on the known functions of RBPs in plant immune response regulation. Future in-depth analysis of RBPs and other related players will unveil the sophisticated regulatory mechanisms of RNA processing during plant immune responses.

  9. Transcriptional responses of Arabidopsis thaliana plants to As (V stress

    Directory of Open Access Journals (Sweden)

    Yuan Joshua S

    2008-08-01

    Full Text Available Abstract Background Arsenic is toxic to plants and a common environmental pollutant. There is a strong chemical similarity between arsenate [As (V] and phosphate (Pi. Whole genome oligonucleotide microarrays were employed to investigate the transcriptional responses of Arabidopsis thaliana plants to As (V stress. Results Antioxidant-related genes (i.e. coding for superoxide dismutases and peroxidases play prominent roles in response to arsenate. The microarray experiment revealed induction of chloroplast Cu/Zn superoxide dismutase (SOD (at2g28190, Cu/Zn SOD (at1g08830, as well as an SOD copper chaperone (at1g12520. On the other hand, Fe SODs were strongly repressed in response to As (V stress. Non-parametric rank product statistics were used to detect differentially expressed genes. Arsenate stress resulted in the repression of numerous genes known to be induced by phosphate starvation. These observations were confirmed with qRT-PCR and SOD activity assays. Conclusion Microarray data suggest that As (V induces genes involved in response to oxidative stress and represses transcription of genes induced by phosphate starvation. This study implicates As (V as a phosphate mimic in the cell by repressing genes normally induced when available phosphate is scarce. Most importantly, these data reveal that arsenate stress affects the expression of several genes with little or unknown biological functions, thereby providing new putative gene targets for future research.

  10. Dematerialization in the defence sector

    Energy Technology Data Exchange (ETDEWEB)

    Hedberg, L.; During Aahs, C.; Eriksson, Bjoern; Jungmar, M. [Stockholm Univ. and Swedish Defence Research Agency (FOI) (Sweden). Environmental Strategies Research Group

    2001-07-01

    The goal of dematerialization is to reduce flows of resources from the biosphere and the lithosphere to the technosphere, and to increase the efficiency within the technosphere. Dematerialization can be obtained in many different ways, for example through product design and changed or reduced use of products. Recycling and reuse of material or products are two ways to achieve more efficient use of resources and reduced exploitation of raw material. Substantial amounts of material are stored within the armed forces. An assessment of the total weight of the defence materiel has been made and the result amounts to about 230 000 tons, mainly different metals. The calculation is not complete and excludes for example munitions. The scrapping of the Bofors S-tank is studied as an example of a MIPS-analysis. The MIPS-analysis is a kind of material flow analysis where the weight of all material affected by human activity related to the life-cycle of a product or service utility is estimated. Each tank is assumed to give 20 tons of recycled steel. Recycling will also lead to avoidance of waste rock and slag from extraction, the 'rucksack'. Comparing recycling of an S-tank with landfilling a material flow of roughly 160 tons from the lithosphere to the technosphere is avoided.

  11. European Defence Community: origins of integration in the defence sphere

    Directory of Open Access Journals (Sweden)

    Іван Васильович Яковюк

    2017-12-01

    Full Text Available There is a tendency among non-historians to force «practioners» of the discipline to justify why the study of a particular episode of the past is so important and to articulate the lessons to be learned from the experience. The fate of international constitutions and treaties is particularly prone to demands of this kind. After all, «constitutional borrowing» has long been a common feature of international law and politics. This article will address one such Treaty from the past. But it does not aspire to preserving its historical integrity; rather to awaken interest in it in the first place.          The European Defence Community (EDC was an ambitious initiative in the first years of the 1950s. Leading European countries had different foreign policy agendas towards it. The EDC. could have been a crucial milestone on the long path towards European integration. European Defense Community (EDC, an abortive attempt by western European powers, with United States support, to counterbalance the overwhelming conventional military ascendancy of the Soviet Union in Europe by the formation of a supranational European army and, in the process, to subsume West German forces into a European force, avoiding the tendentious problem of West German rearmament. One can trace the U.S. influence from the very first stages of the EDC. negotiations. Even in the agreement of the EDC., the footprints of U.S. policies can be observed, bringing the NATO Alliance to the forefront. The EDC. is also interrelated with the Marshall Plan, which leads us to think that the EDC. was not solely a European dream as has been widely argued, but rather an instrument of U.S. foreign policy, which could be resorted to as and when needed.          Influenced by the Korean War, the French politician René Pleven evolved a plan that later was put forward by the French foreign minister Robert Schuman at a meeting of the Council of Europe in 1951. Though the weaker

  12. Fate of polycyclic aromatic hydrocarbons in plant-soil systems: Plant responses to a chemical stress in the root zone

    Energy Technology Data Exchange (ETDEWEB)

    Hoylman, Anne M. [Univ. of Tennessee, Knoxville, TN (United States)

    1994-01-01

    Under laboratory conditions selected to maximize root uptake, plant tissue distribution of PAH-derived 14C was largely limited to root tissue of Malilotus alba. These results suggest that plant uptake of PAHs from contaminated soil via roots, and translocation to aboveground plant tissues (stems and leaves), is a limited mechanism for transport into terrestrial food chains. However, these data also indicate that root surface sorption of PAHs may be important for plants grown in soils containing elevated concentration PAHs. Root surface sorption of PAHs may be an important route of exposure for plants in soils containing elevated concentrations of PAHS. Consequently, the root-soil interface may be the site of plant-microbial interactions in response to a chemical stress. In this study, evidence of a shift in carbon allocation to the root zone of plants exposed to phenanthrene and corresponding increases in soil respiration and heterotrophic plate counts provide evidence of a plant-microbial response to a chemical stress. The results of this study establish the importance of the root-soil interface for plants growing in PAH contaminated soil and indicate the existence of plant-microbial interactions in response to a chemical stress. These results may provide new avenues of inquiry for studies of plant toxicology, plant-microbial interactions in the rhizosphere, and environmental fates of soil contaminants. In addition, the utilization of plants to enhance the biodegradation of soil contaminants may require evaluation of plant physiological changes and plant shifts in resource allocation.

  13. Plant natriuretic peptides are apoplastic and paracrine stress response molecules

    KAUST Repository

    Wang, Yuhua

    2011-04-07

    Higher plants contain biologically active proteins that are recognized by antibodies against human atrial natriuretic peptide (ANP). We identified and isolated two Arabidopsis thaliana immunoreactive plant natriuretic peptide (PNP)-encoding genes, AtPNP-A and AtPNP-B, which are distantly related members of the expansin superfamily and have a role in the regulation of homeostasis in abiotic and biotic stresses, and have shown that AtPNP-A modulates the effects of ABA on stomata. Arabidopsis PNP (PNP-A) is mainly expressed in leaf mesophyll cells, and in protoplast assays we demonstrate that it is secreted using AtPNP-A:green fluorescent protein (GFP) reporter constructs and flow cytometry. Transient reporter assays provide evidence that AtPNP-A expression is enhanced by heat, osmotica and salt, and that AtPNP-A itself can enhance its own expression, thereby generating a response signature diagnostic for paracrine action and potentially also autocrine effects. Expression of native AtPNP-A is enhanced by osmotica and transiently by salt. Although AtPNP-A expression is induced by salt and osmotica, ABA does not significantly modulate AtPNP-A levels nor does recombinant AtPNP-A affect reporter expression of the ABA-responsive RD29A gene. Together, these results provide experimental evidence that AtPNP-A is stress responsive, secreted into the apoplastic space and can enhance its own expression. Furthermore, our findings support the idea that AtPNP-A, together with ABA, is an important component in complex plant stress responses and that, much like in animals, peptide signaling molecules can create diverse and modular signals essential for growth, development and defense under rapidly changing environmental conditions. © 2011 The Author.

  14. Herboxidiene triggers splicing repression and abiotic stress responses in plants

    KAUST Repository

    Alshareef, Sahar

    2017-03-27

    Background Constitutive and alternative splicing of pre-mRNAs from multiexonic genes controls the diversity of the proteome; these precisely regulated processes also fine-tune responses to cues related to growth, development, and stresses. Small-molecule inhibitors that perturb splicing provide invaluable tools for use as chemical probes to uncover the molecular underpinnings of splicing regulation and as potential anticancer compounds. Results Here, we show that herboxidiene (GEX1A) inhibits both constitutive and alternative splicing. Moreover, GEX1A activates genome-wide transcriptional patterns involved in abiotic stress responses in plants. GEX1A treatment -activated ABA-inducible promoters, and led to stomatal closure. Interestingly, GEX1A and pladienolide B (PB) elicited similar cellular changes, including alterations in the patterns of transcription and splicing, suggesting that these compounds might target the same spliceosome complex in plant cells. Conclusions Our study establishes GEX1A as a potent splicing inhibitor in plants that can be used to probe the assembly, dynamics, and molecular functions of the spliceosome and to study the interplay between splicing stress and abiotic stresses, as well as having potential biotechnological applications.

  15. Plant responses to environmental stresses-from gene to biotechnology.

    Science.gov (United States)

    Ahanger, Mohammad Abass; Akram, Nudrat Aisha; Ashraf, Muhammad; Alyemeni, Mohammed Nasser; Wijaya, Leonard; Ahmad, Parvaiz

    2017-07-01

    Increasing global population, urbanization and industrialization are increasing the rate of conversion of arable land into wasteland. Supplying food to an ever-increasing population is one of the biggest challenges that agriculturalists and plant scientists are currently confronting. Environmental stresses make this situation even graver. Despite the induction of several tolerance mechanisms, sensitive plants often fail to survive under environmental extremes. New technological approaches are imperative. Conventional breeding methods have a limited potential to improve plant genomes against environmental stress. Recently, genetic engineering has contributed enormously to the development of genetically modified varieties of different crops such as cotton, maize, rice, canola and soybean. The identification of stress-responsive genes and their subsequent introgression or overexpression within sensitive crop species are now being widely carried out by plant scientists. Engineering of important tolerance pathways, like antioxidant enzymes, osmolyte accumulation, membrane-localized transporters for efficient compartmentation of deleterious ions and accumulation of essential elements and resistance against pests or pathogens is also an area that has been intensively researched. In this review, the role of biotechnology and its successes, prospects and challenges in developing stress-tolerant crop cultivars are discussed.

  16. Inter-plant communication through mycorrhizal networks mediates complex adaptive behaviour in plant communities.

    Science.gov (United States)

    Gorzelak, Monika A; Asay, Amanda K; Pickles, Brian J; Simard, Suzanne W

    2015-05-15

    Adaptive behaviour of plants, including rapid changes in physiology, gene regulation and defence response, can be altered when linked to neighbouring plants by a mycorrhizal network (MN). Mechanisms underlying the behavioural changes include mycorrhizal fungal colonization by the MN or interplant communication via transfer of nutrients, defence signals or allelochemicals. We focus this review on our new findings in ectomycorrhizal ecosystems, and also review recent advances in arbuscular mycorrhizal systems. We have found that the behavioural changes in ectomycorrhizal plants depend on environmental cues, the identity of the plant neighbour and the characteristics of the MN. The hierarchical integration of this phenomenon with other biological networks at broader scales in forest ecosystems, and the consequences we have observed when it is interrupted, indicate that underground 'tree talk' is a foundational process in the complex adaptive nature of forest ecosystems. Published by Oxford University Press on behalf of the Annals of Botany Company.

  17. Disease resistance or growth: the role of plant hormones in balancing immune responses and fitness costs

    NARCIS (Netherlands)

    Denance, N.; Sanchez Vallet, A.; Goffner, D.; Molina, A.

    2013-01-01

    Plant growth and response to environmental cues are largely governed by phytohormones. The plant hormones ethylene, jasmonic acid, and salicylic acid (SA) play a central role in the regulation of plant immune responses. In addition, other plant hormones, such as auxins, abscisic acid (ABA),

  18. Crossfit analysis: a novel method to characterize the dynamics of induced plant responses

    NARCIS (Netherlands)

    Jansen, J.J.; Van Dam, N.M.; Hoefsloot, H.C.J.; Smilde, A.K.

    2009-01-01

    Background Many plant species show induced responses that protect them against exogenous attacks. These responses involve the production of many different bioactive compounds. Plant species belonging to the Brassicaceae family produce defensive glucosinolates, which may greatly influence their

  19. Crossfit analysis: a novel method to characterize the dynamics of induced plant responses

    NARCIS (Netherlands)

    Jansen, J.J.; van Dam, N.M.; Hoefsloot, H.C.J.; Smilde, A.K.

    2009-01-01

    Background: Many plant species show induced responses that protect them against exogenous attacks. These responses involve the production of many different bioactive compounds. Plant species belonging to the Brassicaceae family produce defensive glucosinolates, which may greatly influence their

  20. Response of equipment in nuclear power plants to airplane crash

    International Nuclear Information System (INIS)

    Schalk, M.; Woelfel, H.

    1976-01-01

    Nuclear power plants in Germany are to be designed against airplane crash. Two problems arise: first, the local problem of penetration as well as local destruction of the building and secondly the airplane induced vibrations of the whole building which cause loadings for secondary systems (equipment). This paper deals especially with the second problem. Floor response spectra due to airplane crash are presented for two different power plant buildings. The influence of various parameters (time history of excitation, direction and location of impact, mathematical model, soil, damping, etc.) are discussed. A comparison with the results of earthquake loading is given. Suggestions are made for developing suitable floor design spectra and using them to analyse multidegree-of-freedom systems. However, the paper gives only a partial answer to the questions arising because of some important restrictions which had to be made. Studies concerning these restrictions are still being conducted and will be presented in a separate paper. (Auth.)

  1. Transcriptional Responses in the Hemiparasitic Plant Triphysaria versicolor to Host Plant Signals1[w

    Science.gov (United States)

    Matvienko, Marta; Torres, Manuel J.; Yoder, John I.

    2001-01-01

    Parasitic plants in the Scrophulariaceae use chemicals released by host plant roots to signal developmental processes critical for heterotrophy. Haustoria, parasitic plant structures that attach to and invade host roots, develop on roots of the hemiparasitic plant Triphysaria versicolor within a few hours of exposure to either maize (Zea mays) root exudate or purified haustoria-inducing factors. We prepared a normalized, subtractive cDNA library enriched for transcripts differentially abundant in T. versicolor root tips treated with the allelopathic quinone 2,6-dimethoxybenzoquinone (DMBQ). Northern analyses estimated that about 10% of the cDNAs represent transcripts strongly up-regulated in roots exposed to DMBQ. Northern and reverse northern analyses demonstrated that most DMBQ-responsive messages were similarly up-regulated in T. versicolor roots exposed to maize root exudates. From the cDNA sequences we assembled a unigene set of 137 distinct transcripts and assigned functions by homology comparisons. Many of the proteins encoded by the transcripts are predicted to function in quinone detoxification, whereas others are more likely associated with haustorium development. The identification of genes transcriptionally regulated by haustorium-inducing factors provides a framework for dissecting genetic pathways recruited by parasitic plants during the transition to heterotrophic growth. PMID:11553755

  2. Sensitivity of nuclear power plant structural response to aircraft impact

    International Nuclear Information System (INIS)

    Buchhardt, F.; Magiera, G.; Matthees, W.; Weber, M.

    1984-01-01

    In this paper a sensitivity study for aircraft impact is performed concerning the excitation of internal components, with particular regard to nonlinear structural material behaviour in the impact area. The nonlinear material values are varied within the bandwidth of suitable material strength, depending on local stiffness pre-calculations. The analyses are then performed on a globally discretized three-dimensional finite element model of a nuclear power plant, using a relatively fine mesh. For specified nodal points results are evaluated by comparing their response spectra. (Author) [pt

  3. Plant transducers of the endoplasmic reticulum unfolded protein response

    KAUST Repository

    Iwata, Yuji; Koizumi, Nozomu

    2012-01-01

    The unfolded protein response (UPR) activates a set of genes to overcome accumulation of unfolded proteins in the endoplasmic reticulum (ER), a condition termed ER stress, and constitutes an essential part of ER protein quality control that ensures efficient maturation of secretory and membrane proteins in eukaryotes. Recent studies on Arabidopsis and rice identified the signaling pathway in which the ER membrane-localized ribonuclease IRE1 (inositol-requiring enzyme 1) catalyzes unconventional cytoplasmic splicing of mRNA, thereby producing the active transcription factor Arabidopsis bZIP60 (basic leucine zipper 60) and its ortholog in rice. Here we review recent findings identifying the molecular components of the plant UPR, including IRE1/bZIP60 and the membrane-bound transcription factors bZIP17 and bZIP28, and implicating its importance in several physiological phenomena such as pathogen response. © 2012 Elsevier Ltd.

  4. Plant transducers of the endoplasmic reticulum unfolded protein response

    KAUST Repository

    Iwata, Yuji

    2012-12-01

    The unfolded protein response (UPR) activates a set of genes to overcome accumulation of unfolded proteins in the endoplasmic reticulum (ER), a condition termed ER stress, and constitutes an essential part of ER protein quality control that ensures efficient maturation of secretory and membrane proteins in eukaryotes. Recent studies on Arabidopsis and rice identified the signaling pathway in which the ER membrane-localized ribonuclease IRE1 (inositol-requiring enzyme 1) catalyzes unconventional cytoplasmic splicing of mRNA, thereby producing the active transcription factor Arabidopsis bZIP60 (basic leucine zipper 60) and its ortholog in rice. Here we review recent findings identifying the molecular components of the plant UPR, including IRE1/bZIP60 and the membrane-bound transcription factors bZIP17 and bZIP28, and implicating its importance in several physiological phenomena such as pathogen response. © 2012 Elsevier Ltd.

  5. RESPONSE OF TOMATO PLANTS EXPOSED TO TREATMENT WITH NANOPARTICLES

    Directory of Open Access Journals (Sweden)

    Tommaso Giordani

    2012-07-01

    Full Text Available In this work the response of Tomato plants cv. Micro-Tom to nanoparticles (NPs treatment was investigated. Tomato seedlings were grown in hydroponic condition and NPs treatments were carried out by adding Fe3O4 or TiO2 NPs to nutrient solution. At the end of treatments, NPs root uptake and tissue deposition were investigated using Environmental Scanning Electron Microscope, equipped with energy dispersive spectroscopy for chemical identification. At morphological level, one week after the beginning of NP treatment, seedlings grown with high concentration of TiO2 NPs showed an abnormal proliferation of root hairs, as compared to the control seedlings and to the seedlings exposed to Fe3O4 NPs, Shoot morphology did not differ in tomato seedlings grown under different conditions and no symptoms of toxicity were observed in NP-treated plants. In order to analyse genetic effects of NPs treatments, RNA transcription was studied in roots of NP-exposed and control plants by Illumina RNA sequencing, evidencing the induction of transposable elements.

  6. Did fleshy fruit pulp evolve as a defence against seed loss rather ...

    Indian Academy of Sciences (India)

    dispersers. Most seed dispersal studies are ecological and examine the role of fruit pulp in promoting seed dispersal. ... Introduction. Endozoochory, the interaction between fleshy-fruited plants ... adaptations for seed defence may have led to the evolution ..... Eriksson O and Bremer B 1992 Pollination systems, dispersal.

  7. Seismic response analysis of floating nuclear power plant

    International Nuclear Information System (INIS)

    Hagiwara, Yutaka; Nakamura, Hideharu; Shiojiri, Hiroo

    1988-01-01

    Since Floating Nuclear Power Plants (FNPs) are considered to be isolated from horizontal seismic motion, it is anticipated to reduce seismic load for plant components and buildings on the barge. On the other hand, barge oscillation and sloshing in the closed basin might be excited by earthquakes, because natural periods of those motions correspond to relatively-long period component (between 2 and 20 seconds) of seismic motion. Therefore, it is necessary to evaluate seismic isolation effects and barge oscillation, for the rational design of FNPs. However, there do not exist any reasonable analytical tools which can evaluate seismic response of floating structures in closed basin. The purpose of the present report is to develop a seismic analysis method for FNPs. The proposed method is based on the finite element method, and the formulation includes fluid-structure interaction, water surface wave, buoyancy effect, and non-linear characteristics of mooring system. Response analysis can be executed in both time-domain and frequency-domain. Shaking table tests were conducted to validate the proposed method of analysis. The test results showed significant isolation effect of floating structure, and apparent interaction between the barge and the basin. And 2-D and 3-D frequency domain analyses and the 2-D linear and non-linear time-domain analyses were done and those analyses could simulate the test results well. (author)

  8. Evaluating physiological responses of plants to salinity stress

    KAUST Repository

    Negrão, Sónia

    2016-10-06

    Background Because soil salinity is a major abiotic constraint affecting crop yield, much research has been conducted to develop plants with improved salinity tolerance. Salinity stress impacts many aspects of a plant’s physiology, making it difficult to study in toto. Instead, it is more tractable to dissect the plant’s response into traits that are hypothesized to be involved in the overall tolerance of the plant to salinity. Scope and conclusions We discuss how to quantify the impact of salinity on different traits, such as relative growth rate, water relations, transpiration, transpiration use efficiency, ionic relations, photosynthesis, senescence, yield and yield components. We also suggest some guidelines to assist with the selection of appropriate experimental systems, imposition of salinity stress, and obtaining and analysing relevant physiological data using appropriate indices. We illustrate how these indices can be used to identify relationships amongst the proposed traits to identify which traits are the most important contributors to salinity tolerance. Salinity tolerance is complex and involves many genes, but progress has been made in studying the mechanisms underlying a plant’s response to salinity. Nevertheless, several previous studies on salinity tolerance could have benefited from improved experimental design. We hope that this paper will provide pertinent information to researchers on performing proficient assays and interpreting results from salinity tolerance experiments.

  9. Global SUMO proteome responses guide gene regulation, mRNA biogenesis, and plant stress responses

    Directory of Open Access Journals (Sweden)

    Magdalena eMazur

    2012-09-01

    Full Text Available Small-ubiquitin-like MOdifier (SUMO is a key regulator of abiotic stress, disease resistance and development in plants. The identification of >350 plant SUMO targets has revealed many processes modulated by SUMO and potential consequences of SUMO on its targets. Importantly, highly related proteins are SUMO-modified in plants, yeast, and metazoans. Overlapping SUMO targets include heat-shock proteins, transcription regulators, histones, histone-modifying enzymes, proteins involved in DNA damage repair, but also proteins involved in mRNA biogenesis and nucleo-cytoplasmic transport. Proteomics studies indicate key roles for SUMO in gene repression by controlling histone (deacetylation activity at genomic loci. The responsible heavily sumoylated transcriptional repressor complexes are recruited by EAR (Ethylene-responsive element binding factor [ERF]-associated Amphiphilic Repression-motif containing transcription factors in plants. These transcription factors are not necessarily themselves a SUMO target. Conversely, SUMO acetylation prevents binding of downstream partners by preventing binding of SIMs (SUMO-interaction peptide motifs presents in these partners, while SUMO acetylation has emerged as mechanism to recruit specifically bromodomains; bromodomain are generally linked with gene activation. These findings strengthen the idea of a bidirectional sumo-/acetylation switch in gene regulation. Quantitative proteomics has highlighted that global sumoylation provides a dynamic response to protein damage involving SUMO chain-mediated protein degradation, but also SUMO E3 ligase-dependent transcription of HSP (Heat-shock protein genes. With these insights in SUMO function and novel technical advancements, we can now study SUMO dynamics in responses to (abiotic stress in plants.

  10. Bruce NGS a loss of flow analysis for effectiveness of level 2 defence-in-depth provisions

    International Nuclear Information System (INIS)

    Won, W.; Jiang, Y.; Kwee, M.; Xue, J.

    2014-01-01

    The concept of defence-in-depth is applied to CANDU (CANada Deuterium Uranium) reactor designs and operations to provide series of levels of defence to prevent accidents progressing and to provide protection for reactor and public safety. The level 2 defence-in-depth provisions are designed to detect and intercept deviation from normal operation in order to prevent anticipated operating occurrences (AOOs) from escalating to accident conditions, and to return the plant to a state of normal operations, according to the Canada Nuclear Safety Commission (CNSC) regulatory document RD-337. Historically, safety analysis has focused on the effectiveness of level 3 defence-in-depth provisions in accident conditions, and the effectiveness of level 2 defence-in-depth has not been assessed. In this study, the effectiveness of Level 2 defence-in-depth is assessed for loss of flow (LOF) events for Bruce Nuclear Generating Station (NGS) A reactors. The level 2 defence-in-depth in Bruce NGS A design is identified to be the stepback function of reactor regulating system (RRS). The behavior of RRS stepback following the initiation of loss of flow event is simulated using RFSP/TUF/RRS - em coupled code. The behavior of full system and single channel is simulated and assessed against the acceptance criteria - fitness for service of systems, structures and components (SSCs). (author)

  11. Bruce NGS a loss of flow analysis for effectiveness of level 2 defence-in-depth provisions

    Energy Technology Data Exchange (ETDEWEB)

    Won, W. [AMEC NSS, Toronto, ON (Canada); Jiang, Y.; Kwee, M.; Xue, J. [Bruce Power, Toronto, ON (Canada)

    2014-07-01

    The concept of defence-in-depth is applied to CANDU (CANada Deuterium Uranium) reactor designs and operations to provide series of levels of defence to prevent accidents progressing and to provide protection for reactor and public safety. The level 2 defence-in-depth provisions are designed to detect and intercept deviation from normal operation in order to prevent anticipated operating occurrences (AOOs) from escalating to accident conditions, and to return the plant to a state of normal operations, according to the Canada Nuclear Safety Commission (CNSC) regulatory document RD-337. Historically, safety analysis has focused on the effectiveness of level 3 defence-in-depth provisions in accident conditions, and the effectiveness of level 2 defence-in-depth has not been assessed. In this study, the effectiveness of Level 2 defence-in-depth is assessed for loss of flow (LOF) events for Bruce Nuclear Generating Station (NGS) A reactors. The level 2 defence-in-depth in Bruce NGS A design is identified to be the stepback function of reactor regulating system (RRS). The behavior of RRS stepback following the initiation of loss of flow event is simulated using RFSP/TUF/RRS{sub -}em coupled code. The behavior of full system and single channel is simulated and assessed against the acceptance criteria - fitness for service of systems, structures and components (SSCs). (author)

  12. Involvement of the ABC transporter BcAtrB and the laccase BcLCC2 in defence of Botrytis cinerea against the broad-spectrum antibiotic 2,4-diacetylphloroglucinol

    NARCIS (Netherlands)

    Schouten, A.; Maksimova, O.; Cuesta Arenas, Y.; Berg, van den G.; Raaijmakers, J.M.

    2008-01-01

    The genetic and biochemical basis of defence mechanisms in plant pathogenic fungi against antifungal compounds produced by antagonistic microorganisms is largely unknown. The results of this study show that both degradative and non-degradative defence mechanisms enable the plant pathogenic fungus

  13. Western European Nuclear Regulators’ Association (WENRA) Views on Defence-in-Depth for New Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Reiman, L.; Routamo, T. [STUK, Helsinki (Finland); Féron, F., E-mail: lasse.reiman@stuk.fi [ASN (France)

    2014-10-15

    WENRA published in 2010 a statement on safety objectives for new NPPs. Based on these objectives, WENRA decided to develop common positions, compiled in a booklet (available on www.wenra.org), on selected key safety issues for the design of new NPPs. One position presents WENRA’s Defence-in-Depth approach, describing WENRA’s expectation that multiple failure events and core melt accidents are considered in the original design of new nuclear power plants; another position presents expectations on the independence between different levels of Defence-in-Depth. (author)

  14. Do competitors modulate rare plant response to precipitation change?

    Science.gov (United States)

    Levine, J.M.; Kathryn, Mceachern A.; Cowan, C.

    2010-01-01

    Ecologists increasingly suspect that climate change will directly impact species physiology, demography, and phenology, but also indirectly affect these measures via changes to the surrounding community. Unfortunately, few studies examine both the direct and indirect pathways of impact. Doing so is important because altered competitive pressures can reduce or magnify the direct responses of a focal species to climate change. Here, we examine the effects of changing rainfall on three rare annual plant species in the presence and absence of competition on the California Channel Islands. We used rain-out shelters and hand watering to exclude and augment early, late, and season-long rainfall, spanning the wide range of precipitation change forecast for the region. In the absence of competition, droughts reduced the population growth rates of two of three focal annuals, while increased rainfall was only sometimes beneficial, As compared to the focal species, the dominant competitors were more sensitive to the precipitation treatments, benefiting from increased season-long precipitation and harmed by droughts. Importantly, the response of two of three competitors to the precipitation treatments tended to be positively correlated with those of the focal annuals. Although this leads to the expectation that increased competition will counter the direct benefits of favorable conditions, such indirect effects of precipitation change proved weak to nonexistent in our experiment. Competitors had little influence on the precipitation response of two focal species, due to their low sensitivity to competition and highly variable precipitation responses. Competition did affect how our third focal species responded to precipitation change, but this effect only approached significance, and whether it truly resulted from competitor response to precipitation change was unclear. Our work suggests that even when competitors respond to climate change, these responses may have little

  15. Both heavy metal-amendment of soil and aphid-infestation increase Cd and Zn concentrations in phloem exudates of a metal-hyperaccumulating plant.

    Science.gov (United States)

    Stolpe, Clemens; Giehren, Franziska; Krämer, Ute; Müller, Caroline

    2017-07-01

    Plants that are able to hyperaccumulate heavy metals show increased concentrations of these metals in their leaf tissue. However, little is known about the concentrations of heavy metals and of organic defence metabolites in the phloem sap of these plants in response to either heavy metal-amendment of the soil or biotic challenges such as aphid-infestation. In this study, we investigated the effects of heavy metal-exposure and of aphid-infestation on phloem exudate composition of the metal hyperaccumulator species Arabidopsis halleri L. O'Kane & Al-Shehbaz (Brassicaceae). The concentrations of elements and of organic defence compounds, namely glucosinolates, were measured in phloem exudates of young and old (mature) leaves of plants challenged either by amendment of the soil with cadmium and zinc and/or by an infestation with the generalist aphid Myzus persicae. Metal-amendment of the soil led to increased concentrations of Cd and Zn, but also of two other elements and one indole glucosinolate, in phloem exudates. This enhanced defence in the phloem sap of heavy metal-hyperaccumulating plants can thus potentially act as effective protection against aphids, as predicted by the elemental defence hypothesis. Aphid-infestation also caused enhanced Cd and Zn concentrations in phloem exudates. This result provides first evidence that metal-hyperaccumulating plants can increase heavy metal concentrations tissue-specifically in response to an attack by phloem-sucking herbivores. Overall, the concentrations of most elements, including the heavy metals, and glucosinolates were higher in phloem exudates of young leaves than in those of old leaves. This defence distribution highlights that the optimal defence theory, which predicts more valuable tissue to be better defended, is applicable for both inorganic and organic defences. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Light response of sunflower and canola as affected by plant density, plant genotype and N fertilization.

    Science.gov (United States)

    Soleymani, A

    2017-08-01

    Crop response to light is an important parameter determining crop growth. Three field (split plots) experiments were conducted to investigate the effects of plant density, plant genotype and N fertilization on the light absorption and light extinction of sunflower (Helianthus annuus L.) and canola (Brassica napus L.). A detailed set of plant growth, light absorption and crop yield and oil related parameters were determined. Light was measured at noon during the sunny days with clear sky. In experiment I, although the plant density (PD) of 14 resulted in the highest rate of sunflower light absorption (31.37%) and light extinction (0.756), the highest rate of grain yield and grain oil yield was resulted at PD12 at 3639 and 1457.9kg/ha, respectively; as well as by genotype SUP.A. In experiment II (canola), PD80 resulted in the highest rate of light absorption (13.13%), light extinction (0.63), grain yield (2189.4kg/ha) and grain oil yield (556.54kg/ha). This was also the case for Genotype H. In experiment III (canola), although N150 resulted in the highest rate of light absorption (10.74%) and light extinction (0.48), the highest rate of grain yield (3413.6kg/ha) and grain oil yield (891.86kg/ha) was resulted at N100 as well as by Genotype H401. Results indicate how light properties, crop growth and yield of sunflower and canola can be affected by plant and environmental parameters, which are also of practical use by farmers. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Can biomass responses to warming at plant to ecosystem levels be predicted by leaf-level responses?

    Science.gov (United States)

    Xia, J.; Shao, J.; Zhou, X.; Yan, W.; Lu, M.

    2015-12-01

    Global warming has the profound impacts on terrestrial C processes from leaf to ecosystem scales, potentially feeding back to climate dynamics. Although numerous studies had investigated the effects of warming on C processes from leaf to plant and ecosystem levels, how leaf-level responses to warming scale up to biomass responses at plant, population, and community levels are largely unknown. In this study, we compiled a dataset from 468 papers at 300 experimental sites and synthesized the warming effects on leaf-level parameters, and plant, population and ecosystem biomass. Our results showed that responses of plant biomass to warming mainly resulted from the changed leaf area rather than the altered photosynthetic capacity. The response of ecosystem biomass to warming was weaker than those of leaf area and plant biomass. However, the scaling functions from responses of leaf area to plant biomass to warming were different in diverse forest types, but functions were similar in non-forested biomes. In addition, it is challenging to scale the biomass responses from plant up to ecosystem. These results indicated that leaf area might be the appropriate index for plant biomass response to warming, and the interspecific competition might hamper the scaling of the warming effects on plant and ecosystem levels, suggesting that the acclimation capacity of plant community should be incorporated into land surface models to improve the prediction of climate-C cycle feedback.

  18. Local plant responses to global problems: Dactylis glomerata responses to different traffic pollutants on roadsides.

    Science.gov (United States)

    Jiménez, M D; de Torre, R; Mola, I; Casado, M A; Balaguer, L

    2018-04-15

    The growing number of road vehicles is a major source of regional and global atmospheric pollution increasing concentrations of CO 2 in the air, and levels of metals in air and soil. Nevertheless, the effects of these pollutants on plants growing at roadsides are poorly documented. We carried out an observational study of unmanipulated plants growing by the road, to identify the morpho-physiological responses in a perennial grass Dactylis glomerata. Firstly, we wanted to know the general effect of traffic intensity and ambient CO 2 and its interactions on different plant traits. Accordingly, we analyzed the photosynthetic response by field A/Ci Response Curves, SLA, pigment pools, foliar nitrogen, carbohydrates and morphological traits in plants at three distances to the road. Secondly, we wanted to know if Dactylis glomerata plants can accumulate metals present on the roadside (Pb, Zn, Cu, and Sr) in their tissues and rhizosphere, and the effect of these metals on morphological traits. The MANCOVA whole model results shown: 1) a significant effect of road ambient CO 2 concentration on morphological traits (not affected by traffic intensity, P interaction CO2 x traffic intensity >0.05), that was mainly driven by a significant negative relationship between the inflorescence number and ambient CO 2 ; 2) a positive and significant relationship between ambient CO 2 and the starch content in leaves (unaffected by traffic intensity); 3) a reduction in J max (electron transport rate) at high traffic intensity. These lines of evidences suggest a decreased photosynthetic capacity due to high traffic intensity and high levels of ambient CO 2 . In addition, Pb, Cu, Zn and Sr were detected in Dactylis glomerata tissues, and Cu accumulated in roots. Finally, we observed that Dactylis glomerata individuals growing at the roadside under high levels of CO 2 and in the presence of metal pollutants, reduced their production of inflorescences. Copyright © 2018 Elsevier Ltd. All

  19. Molecular mechanisms of plant competition: neighbour detection and response strategies

    NARCIS (Netherlands)

    Pierik, R.; Mommer, L.; Voesenek, L.A.C.J.

    2013-01-01

    Plant competition determines the diversity and species abundance of natural communities as well as potential yields in agricultural systems. Understanding the mechanisms of plant competition is instrumental to understanding plant performance in true vegetations. In this review, we will address

  20. Pathogenesis and host defence against Mucorales: the role of cytokines and interaction with antifungal drugs.

    Science.gov (United States)

    Roilides, Emmanuel; Antachopoulos, Charalampos; Simitsopoulou, Maria

    2014-12-01

    Innate immune response, including macrophages, neutrophils and dendritic cells and their respective receptors, plays an important role in host defences against Mucorales with differential activity against specific fungal species, while adaptive immunity is not the first line of defence. A number of endogenous and exogenous factors, such as cytokines and growth factors as well as certain antifungal agents have been found that they influence innate immune response to these organisms. Used alone or especially in combination have been shown to exert antifungal effects against Mucorales species. These findings suggest novel ways of adjunctive therapy for patients with invasive mucormycosis. © 2014 Blackwell Verlag GmbH.

  1. The plant cell nucleus: a true arena for the fight between plants and pathogens.

    Science.gov (United States)

    Deslandes, Laurent; Rivas, Susana

    2011-01-01

    Communication between the cytoplasm and the nucleus is a fundamental feature shared by both plant and animal cells. Cellular factors involved in the transport of macromolecules through the nuclear envelope, including nucleoporins, importins and Ran-GTP related components, are conserved among a variety of eukaryotic systems. Interestingly, mutations in these nuclear components compromise resistance signalling, illustrating the importance of nucleocytoplasmic trafficking in plant innate immunity. Indeed, spatial restriction of defence regulators by the nuclear envelope and stimulus-induced nuclear translocation constitute an important level of defence-associated gene regulation in plants. A significant number of effectors from different microbial pathogens are targeted to the plant cell nucleus. In addition, key host factors, including resistance proteins, immunity components, transcription factors and transcriptional regulators shuttle between the cytoplasm and the nucleus, and their level of nuclear accumulation determines the output of the defence response, further confirming the crucial role played by the nucleus during the interaction between plants and pathogens. Here, we discuss recent findings that situate the nucleus at the frontline of the mutual recognition between plants and invading microbes.

  2. Functional analysis of Arabidopsis immune-related MAPKs uncovers a role for MPK3 as negative regulator of inducible defences

    KAUST Repository

    Frei dit Frey, Nicolas

    2014-06-30

    Background Mitogen-activated protein kinases (MAPKs) are key regulators of immune responses in animals and plants. In Arabidopsis, perception of microbe-associated molecular patterns (MAMPs) activates the MAPKs MPK3, MPK4 and MPK6. Increasing information depicts the molecular events activated by MAMPs in plants, but the specific and cooperative contributions of the MAPKs in these signalling events are largely unclear. Results In this work, we analyse the behaviour of MPK3, MPK4 and MPK6 mutants in early and late immune responses triggered by the MAMP flg22 from bacterial flagellin. A genome-wide transcriptome analysis reveals that 36% of the flg22-upregulated genes and 68% of the flg22-downregulated genes are affected in at least one MAPK mutant. So far MPK4 was considered as a negative regulator of immunity, whereas MPK3 and MPK6 were believed to play partially redundant positive functions in defence. Our work reveals that MPK4 is required for the regulation of approximately 50% of flg22-induced genes and we identify a negative role for MPK3 in regulating defence gene expression, flg22-induced salicylic acid accumulation and disease resistance to Pseudomonas syringae. Among the MAPK-dependent genes, 27% of flg22-upregulated genes and 76% of flg22-downregulated genes require two or three MAPKs for their regulation. The flg22-induced MAPK activities are differentially regulated in MPK3 and MPK6 mutants, both in amplitude and duration, revealing a highly interdependent network. Conclusions These data reveal a new set of distinct functions for MPK3, MPK4 and MPK6 and indicate that the plant immune signalling network is choreographed through the interplay of these three interwoven MAPK pathways.

  3. Defence in depth in nuclear safety

    International Nuclear Information System (INIS)

    Jayakumar, J.S.

    2016-01-01

    Nuclear energy is clean and can prevent global warming and hence it has a lot of importance in the current world. In order for the safe and reliable operation of the NPP, a defence in depth concept has been practised, so that even one level of protection fails the subsequent one will contain the hazardous situation. Various levels, both from consideration of the physical barriers and implementation are described in this paper. Three major accidents happened in nuclear reactors are analysed from the defence in depth concept and shortcomings are discussed. (author)

  4. Safety improvements at Canadian nuclear power plants in the aftermath of Fukushima accident

    International Nuclear Information System (INIS)

    Rzentkowski, G.; Khouaja, H.

    2014-01-01

    This paper describes the safety review of operating nuclear power plants undertaken by the Canadian Nuclear Safety Commission in light of the March 11, 2011 accident at the Fukushima Daiichi Nuclear Power Plants (NPPs). The review confirmed that the Canadian NPPs are robust and have a strong design relying on multiple layers of defence to protect the public from credible external events. Nevertheless, in the spirit of continuous safety improvements, the review identified a number of recommendations to further strengthen reactor defence-in-depth in preventing and mitigating the consequences of beyond design basis accidents, enhance onsite and offsite emergency response, and improve the CNSC regulatory framework. Progress achieved to date, in implementing these measures, is described in this paper along with a summary of safety benefits for each level of the reactor defence-in-depth. (author)

  5. Safety improvements at Canadian nuclear power plants in the aftermath of Fukushima accident

    Energy Technology Data Exchange (ETDEWEB)

    Rzentkowski, G.; Khouaja, H. [Canadian Nuclear Safety Commission, Ottawa, ON (Canada)

    2014-07-01

    This paper describes the safety review of operating nuclear power plants undertaken by the Canadian Nuclear Safety Commission in light of the March 11, 2011 accident at the Fukushima Daiichi Nuclear Power Plants (NPPs). The review confirmed that the Canadian NPPs are robust and have a strong design relying on multiple layers of defence to protect the public from credible external events. Nevertheless, in the spirit of continuous safety improvements, the review identified a number of recommendations to further strengthen reactor defence-in-depth in preventing and mitigating the consequences of beyond design basis accidents, enhance onsite and offsite emergency response, and improve the CNSC regulatory framework. Progress achieved to date, in implementing these measures, is described in this paper along with a summary of safety benefits for each level of the reactor defence-in-depth. (author)

  6. The Ecohydrological Context of Drought and Classification of Plant Responses

    Science.gov (United States)

    Feng, X.; Ackerly, D.; Dawson, T. E.; Manzoni, S.; Skelton, R. P.; Vico, G.; Thompson, S. E.

    2017-12-01

    Many recent studies on drought-induced vegetation mortality have explored how plant functional traits, and classifications of such traits along axes of, e.g., isohydry - anisohydry, might contribute to predicting drought survival and recovery. As these studies proliferate, concerns are growing about the consistency and predictive value of such classifications. Here, we outline the basis for a systematic classification of drought strategies that accounts for both environmental conditions and functional traits. We (1) identify drawbacks of exiting isohydricity and trait-based metrics, (2) identify major axes of trait and environmental variation that determine drought mortality pathways (hydraulic failure and carbon starvation) using non-dimensional trait groups, and (3) demonstrate that these trait groupings predict physiological drought outcomes using both measured and synthetic data. In doing so we untangle some confounding effects of environment and trait variations that undermine current classification schemes, outline a pathway to progress towards a general classification of drought vulnerability, and advocate for more careful treatment of the environmental conditions within which plant drought responses occur.

  7. Plant response to nutrient availability across variable bedrock geologies

    Science.gov (United States)

    Castle, S.C.; Neff, J.C.

    2009-01-01

    We investigated the role of rock-derived mineral nutrient availability on the nutrient dynamics of overlying forest communities (Populus tremuloides and Picea engelmanni-Abies lasiocarpa v. arizonica) across three parent materials (andesite, limestone, and sandstone) in the southern Rocky Mountains of Colorado. Broad geochemical differences were observed between bedrock materials; however, bulk soil chemistries were remarkably similar between the three different sites. In contrast, soil nutrient pools were considerably different, particularly for P, Ca, and Mg concentrations. Despite variations in nutrient stocks and nutrient availability in soils, we observed relatively inflexible foliar concentrations and foliar stoichiometries for both deciduous and coniferous species. Foliar nutrient resorption (P and K) in the deciduous species followed patterns of nutrient content across substrate types, with higher resorption corresponding to lower bedrock concentrations. Work presented here indicates a complex plant response to available soil nutrients, wherein plant nutrient use compensates for variations in supply gradients and results in the maintenance of a narrow range in foliar stoichiometry. ?? 2008 Springer Science+Business Media, LLC.

  8. Reduced mycorrhizal responsiveness leads to increased competitive tolerance in an invasive exotic plant

    Science.gov (United States)

    Lauren P. Waller; Ragan M. Callaway; John N. Klironomos; Yvette K. Ortega; John L. Maron

    2016-01-01

    1. Arbuscular mycorrhizal (AM) fungi can exert a powerful influence on the outcome of plant–plant competition. Since some exotic plants interact differently with soil biota such as AM fungi in their new range, range-based shifts in AM responsiveness could shift competitive interactions between exotic and resident plants, although this remains poorly studied. 2. We...

  9. Response of Maize Plant to Phosphorus Fertilization on Typic Distrudepts

    Directory of Open Access Journals (Sweden)

    Antonius Kasno

    2009-05-01

    Full Text Available On the acid soil, phosphorus nutrients become critical for agricultural crops growth. At the present, price of fertilizers significantly increase and fertilizers are not available. These conditions can affect on soil productivity and crop production. The objective of these research were to study the response of maize (Zea mays L. to phosphate fertilizers on Inceptisol. The research was conducted in Cicadas Village on Typic Dystrudept. Experiment was conducted in a randomized completely block design, with 8 treatments and three replications. Treatments consisted of 6 dosages of P fertilizers, which were P source is SP-36 WIKA Agro 0, 10, 20, 40, 60 and 80 kg ha-1. SP-36 and Tunisia rock phosphate (40 kg P ha-1 were used for standard. Pioneer 12 variety of maized was used as an indicator. Plot size was 5 m x 6 m and the maize was planting with distance of 75 cm x 20 cm with one seed per hole. The results showed that organic C and N, P (extracted by Bray 1, K and CEC on the soil were low. Phosphate fertilizers significantly increased which was P extracted by HCl 25% from 24 to 67 mg P 100 g-1 soil and which were extracted by Bray 1 increased from 0,87 to 63.31 mg P kg-1 soil. Phosphate fertilizers significantly increased plant height from 175.2 cm become to 221.1 cm. Plant height of maize using SP-36 WIKA Agro fertilizer (210.6 cm was similar to plant heigh using SP-36 fertilizer (213.4 cm but less height from Tunisia rock phosphate. The yield of maize on SP-36 WIKA Agro (4.94 t ha-1 were linely higher than SP-36 (4.69 t ha-1, significantly was higher than that of Tunisia rock phosphate. Maximum dosage of SP-36 fertilizer was 66.67 kg P ha-1, and optimum dosage was 42 kg P ha-1. Value of Relative Agronomic Effectiveness SP-36 WIKA Agro fertilizer was heigher than SP-36.

  10. Involvement of potato (Solanum tuberosum L.) MKK6 in response to potato virus Y.

    Science.gov (United States)

    Lazar, Ana; Coll, Anna; Dobnik, David; Baebler, Spela; Bedina-Zavec, Apolonija; Zel, Jana; Gruden, Kristina

    2014-01-01

    Mitogen-activated protein kinase (MAPK) cascades have crucial roles in the regulation of plant development and in plant responses to stress. Plant recognition of pathogen-associated molecular patterns or pathogen-derived effector proteins has been shown to trigger activation of several MAPKs. This then controls defence responses, including synthesis and/or signalling of defence hormones and activation of defence related genes. The MAPK cascade genes are highly complex and interconnected, and thus the precise signalling mechanisms in specific plant-pathogen interactions are still not known. Here we investigated the MAPK signalling network involved in immune responses of potato (Solanum tuberosum L.) to Potato virus Y, an important potato pathogen worldwide. Sequence analysis was performed to identify the complete MAPK kinase (MKK) family in potato, and to identify those regulated in the hypersensitive resistance response to Potato virus Y infection. Arabidopsis has 10 MKK family members, of which we identified five in potato and tomato (Solanum lycopersicum L.), and eight in Nicotiana benthamiana. Among these, StMKK6 is the most strongly regulated gene in response to Potato virus Y. The salicylic acid treatment revealed that StMKK6 is regulated by the hormone that is in agreement with the salicylic acid-regulated domains found in the StMKK6 promoter. The involvement of StMKK6 in potato defence response was confirmed by localisation studies, where StMKK6 accumulated strongly only in Potato-virus-Y-infected plants, and predominantly in the cell nucleus. Using a yeast two-hybrid method, we identified three StMKK6 targets downstream in the MAPK cascade: StMAPK4_2, StMAPK6 and StMAPK13. These data together provide further insight into the StMKK6 signalling module and its involvement in plant defence.

  11. CSIR eNews: Defence peace safety and security

    CSIR Research Space (South Africa)

    CSIR

    2008-12-01

    Full Text Available The CSIR Defence peace safety and security research unit aims to provide a defence evaluation and research institute capability for the Department of Defence. It also serves as the 'in-house' S&T capability of key government departments and agencies...

  12. Civil defence and disaster control services

    International Nuclear Information System (INIS)

    Kolb, P.W.

    1986-01-01

    Today's systems of civil defence and disaster control services are the result of a long process of development, which is outlined for the Federal Republic of Germany. The present organisational and legal systems are explained, together with the institutions concerned. (DG) [de

  13. Defence Output Measures: An Economics Perspective

    Science.gov (United States)

    2011-11-01

    positive or negative impact of defence spending on growth and there is evidence supporting both impacts! The divergent results reflect the need for a...It also protects national interests, including independence and ‘appropriate sovereignty’ (e.g. protecting a nation’s interests in a globalised

  14. The Cooperative Ballistic Missile Defence Game

    NARCIS (Netherlands)

    Evers, L.; Barros, A.I.; Monsuur, H.

    2013-01-01

    The increasing proliferation of ballistic missiles and weapons of mass destruction poses new risks worldwide. For a threatened nation and given the characteristics of this threat a layered ballistic missile defence system strategy appears to be the preferred solution. However, such a strategy

  15. Probiotics: beneficial factors of the defence system.

    Science.gov (United States)

    Antoine, Jean Michel

    2010-08-01

    Probiotics, defined as living micro-organisms that provide a health benefit to the host when ingested in adequate amounts, have been used traditionally as food components to help the body to recover from diarrhoea. They are commonly ingested as part of fermented foods, mostly in fresh fermented dairy products. They can interact with the host through different components of the gut defence systems. There is mounting clinical evidence that some probiotics, but not all, help the defence of the host as demonstrated by either a shorter duration of infections or a decrease in the host's susceptibility to pathogens. Different components of the gut barrier can be involved in the strengthening of the body's defences: the gut microbiota, the gut epithelial barrier and the immune system. Many studies have been conducted in normal free-living subjects or in subjects during common infections like the common cold and show that some probiotic-containing foods can improve the functioning of or strengthen the body's defence. Specific probiotic foods can be included in the usual balanced diet of consumers to help them to better cope with the daily challenges of their environment.

  16. The long road of antimissile defence

    International Nuclear Information System (INIS)

    Gere, Francois

    2001-01-01

    The author proposes a discussion of the elaboration of the National Missile Defence (NMD) by the new US administration in 2001. He first reports the evolution of this concept which resulted in 1999 with the National Missile Defence Act, produced by a commission chaired by Rumsfeld and aimed at the assessment of the threat of ballistic missiles in the world. Before that, in the 1960, the USA already tried to protect themselves by designing two type of missiles: long range interceptors (Nike Zeus), and short range missiles (Sprint). Later, Reagan launched the Strategic Defence Initiative (SDI). By the end of Cold War, the SDI was downgraded into smaller programmes. In a second part, the author discusses some elements of the NMD content: definition of objectives over 20 years, technical and strategic obstacles, definition of Rogue States. In a third part, he proposes an overview of the relationships between antimissile defence and nuclear deterrence, notably through the ABM Treaty, and with problem raised by Arms of Mass Destruction (AMD). In the last part, he comments reactions (mainly opposition) of different countries (Russia, China, European countries and particularly Germany), and proposes some possible true motivations for the creation of the NMD

  17. South Africa's Defence Industrial Participation in Perspective

    African Journals Online (AJOL)

    jvdyk

    2014-03-31

    Mar 31, 2014 ... product and improved the economy through the retention of some ... and maintaining a defence industrial base (DIB) in those countries ... by the Department of Trade and Industry (dti) that focuses primarily ... work share on the purchased equipment (co-production), ..... These upgrades are now an integral.

  18. South Africa's Defence Industrial Participation in Perspective

    African Journals Online (AJOL)

    jvdyk

    2014-03-31

    Mar 31, 2014 ... product and improved the economy through the retention of some 58 000 jobs. ... and maintaining a defence industrial base (DIB) in those countries that have the ... by the Department of Trade and Industry (dti) that focuses primarily on civil industry ... work share on the purchased equipment (co-production), ...

  19. The Immune System and Bodily Defence

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 2. The Immune System and Bodily Defence How Do Parasites and the Immune System Choose their Dances? Vineeta Bal Satyajit Rath. Series Article Volume 2 Issue 2 February 1997 pp 17-24 ...

  20. The Immune System and Bodily Defence

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 6. The Immune System and Bodily Defence How Does the Immune System Organize Itself so as to Connect Target Recognition to Expected Functions? Vineeta Bal Satyajit Rath. Series Article Volume 2 Issue 6 June 1997 pp 25-38 ...

  1. The Immune System and Bodily Defence

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 9. The Immune System and Bodily Defence How Does the Immune System Recognize Everything Under the Sun? Vineeta Bal Satyajit Rath. Series Article Volume 2 Issue 9 September 1997 pp 6-10 ...

  2. Assessment methodology for air defence control systems

    CSIR Research Space (South Africa)

    Oosthuizen, R

    2013-09-01

    Full Text Available In Command and Control, humans have to make sense of the situation to support decision making on the required action. Development of an Air Defence Control system through a Systems Engineering process starts with assessment of existing systems...

  3. Menadione Sodium Bisulphite (MSB) enhances the resistance response of tomato, leading to repel mollusc pests.

    Science.gov (United States)

    Carrillo-Perdomo, Estefanía; Jiménez-Arias, David; Aller, Ángel; Borges, Andrés A

    2016-05-01

    Snails and slugs are terrestrial gastropods representing an important biotic stress that adversely affects crop yields. These pests are typically controlled with molluscicides, which produce pollution and toxicity and further induce the evolution of resistance mechanisms, making pest management even more challenging. In our work, we have assessed the efficacy of two different plant defence activators, menadione sodium bisulphite (MSB) and 1,2,3-benzothiadiazole-7-thiocarboxylic acid S-methyl ester (BTH), as inducers of resistance mechanisms of the model plant for defence, Solanum lycopersicum, against the generalist mollusc Theba grasseti (Helicidae). The study was designed to test the feeding behaviour and choice of snails, and also to analyse the expression profile of different genes specifically involved in defence against herbivores and wounds. Our data suggest that, through the downregulation of the terpene volatile genes and the production of proteinase inhibitors, treated MSB plants may be less apparent to herbivores that use herbivore-induced plant volatiles for host location. By contrast, BTH was not effective in the treatment of the pest, probably owing to an antagonistic effect derived from the induction of both salicylic-acid-dependent and jasmonic-acid-dependent pathways. This information is crucial to determine the genetic basis of the choice of terrestrial gastropod herbivores in tomato, providing valuable insight into how the plant defence activators could control herbivore pests in plants. Our work not only reports for the first time the interaction between tomato and a mollusc pest but also presents the action of two plant defence inductors that seems to produce opposed responses by inducing resistance mechanisms through different defence pathways. © 2015 Society of Chemical Industry.

  4. Emergency Preparedness and Response at Nuclear Power Plants in Pakistan

    Energy Technology Data Exchange (ETDEWEB)

    Khan, L. A.; Qamar, M. A.; Liaquat, M.R., E-mail: samasl@yahoo.com [Pakistan Atomic Energy Commission, Islamabad (Pakistan)

    2014-10-15

    Emergency preparedness and response arrangements at Nuclear Power Plants (NPPs) in Pakistan have been reevaluated in the light of Fukushima Daiichi accident. Appropriate measures have been taken to strengthen and effectively implement the on-site and off-site emergency plans. Verification of these plans is conducted through regulatory review and by witnessing periodic emergency drills and exercises conducted by the NPPs in the fulfilment of the regulatory requirements. Emergency Planning Zones (EPZs) have been revised at NPPs. A multi discipline reserve force has been formed for assistance during severe accidents. Nuclear Emergency Management System (NEMS) has been established at the national level in order to make necessary arrangements for responding to nuclear and radiological emergencies. Training programs for first responders and medical professionals have been launched. Emergencies coordination centres have been established at national and corporate levels. Public awareness program has been initiated to ensure that the surrounding population is provided with appropriate information on emergency planning and response. To share national and international operational experience, Pakistan has arranged various workshops and developed a strong link with International Atomic Energy Agency (IAEA). (author)

  5. Foliar aphid feeding recruits rhizosphere bacteria and primes plant immunity against pathogenic and non-pathogenic bacteria in pepper.

    Science.gov (United States)

    Lee, Boyoung; Lee, Soohyun; Ryu, Choong-Min

    2012-07-01

    Plants modulate defence signalling networks in response to different biotic stresses. The present study evaluated the effect of a phloem-sucking aphid on plant defence mechanisms in pepper (Capsicum annuum) during subsequent pathogen attacks on leaves and rhizosphere bacteria on roots. Plants were pretreated with aphids and/or the chemical trigger benzothiadiazol (BTH) 7 d before being challenged with two pathogenic bacteria, Xanthomonas axonopodis pv. vesicatoria (Xav) as a compatible pathogen and X. axonopodis pv. glycines (Xag) as an incompatible (non-host) pathogen. Disease severity was noticeably lower in aphid- and BTH + aphid-treated plants than in controls. Although treatment with BTH or aphids alone did not affect the hypersensitive response (HR) against Xag strain 8ra, the combination treatment had a synergistic effect on the HR. The aphid population was reduced by BTH pretreatment and by combination treatment with BTH and bacterial pathogens in a synergistic manner. Analysis of the expression of the defence-related genes Capsicum annum pathogenesis-related gene 9 (CaPR9), chitinase 2 (CaCHI2), SAR8·2 and Lipoxygenase1 (CaLOX1) revealed that aphid infestation resulted in the priming of the systemic defence responses against compatible and incompatible pathogens. Conversely, pre-challenge with the compatible pathogen Xav on pepper leaves significantly reduced aphid numbers. Aphid infestation increased the population of the beneficial Bacillus subtilis GB03 but reduced that of the pathogenic Ralstonia solanacearum SL1931. The expression of defence-related genes in the root and leaf after aphid feeding indicated that the above-ground aphid infestation elicited salicylic acid and jasmonic acid signalling throughout the whole plant. The findings of this study show that aphid feeding elicits plant resistance responses and attracts beneficial bacterial populations to help the plant cope with subsequent pathogen attacks.

  6. Public Private Business Models for Defence Acquisition - A Multiple Case Study of Defence Acquisition Projects in the UK

    OpenAIRE

    Ekström, Thomas

    2012-01-01

    Since the ending of the Cold War, the defence sector, particularly the areas of military logistics and defence acquisition, has been undergoing a comprehensive transformation. There are several factors that explain this transformation: changes in defence and security policies for nations and organisations; reductions in defence expenditure; participation in Peace Support Operations; Lessons Learned from these operations, especially in the area of logistics; revolutionary development in the ar...

  7. Tritrophic interactions in wild and cultivated brassicaceous plant species

    NARCIS (Netherlands)

    Gols, R.

    2008-01-01

    Plants have evolved a range of defence traits that prevent or reduce attack by insect herbivores. Direct defence traits hamper or reduce the performance and behaviour of the herbivores, whereas indirect defence promote the efficiency of natural enemies to attack the herbivores. Here, I focused on

  8. Interactions between nutritional approaches and defences against microbial diseases in small ruminants.

    Science.gov (United States)

    Caroprese, M; Giannenas, I; Fthenakis, G C

    2015-12-14

    Objective of this review is to discuss the role of small ruminant diet in the defence of these animals against microbial diseases, in relation to different experimental approaches and various stressors acting on animals. The effects of various diets in immune reactions and animal defences are presented. Also, effects in relation to the species studied and the type of stressors acting on animals are discussed. Evidence is provided about the significance of the diet in enhancing immune responses of small ruminants during specific conditions, e.g., around parturition, during lactation, as well as in growing lambs or kids. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Evolution of host innate defence: insights from Caenorhabditis elegans and primitive invertebrates.

    Science.gov (United States)

    Irazoqui, Javier E; Urbach, Jonathan M; Ausubel, Frederick M

    2010-01-01

    The genetically tractable model organism Caenorhabditis elegans was first used to model bacterial virulence in vivo a decade ago. Since then, great strides have been made in identifying the host response pathways that are involved in its defence against infection. Strikingly, C. elegans seems to detect, and respond to, infection without the involvement of its homologue of Toll-like receptors, in contrast to the well-established role for these proteins in innate immunity in mammals. What, therefore, do we know about host defence mechanisms in C. elegans and what can they tell us about innate immunity in higher organisms?

  10. Evolution of host innate defence: insights from C. elegans and primitive invertebrates

    Science.gov (United States)

    Irazoqui, Javier E.; Urbach, Jonathan M.; Ausubel, Frederick M.

    2010-01-01

    Preface The genetically tractable model organism Caenorhabditis elegans was first used to model bacterial virulence in vivo a decade ago. Since then, great strides have been made in the identification of host response pathways that are involved in the defence against infection. Strikingly, C. elegans seems to detect and respond to infection without the involvement of its Toll-like receptor homologue, in contrast to the well-established role for these proteins in innate immunity in mammals. What, therefore, do we know about host defence mechanisms in C. elegans, and what can they tell us about innate immunity in higher organisms? PMID:20029447

  11. Effects of silicon treatment and inoculation with Fusarium oxysporum f. sp. vasinfectum on cellular defences in root tissues of two cotton cultivars.

    Science.gov (United States)

    Whan, Jennifer A; Dann, Elizabeth K; Aitken, Elizabeth A B

    2016-08-01

    Silicon has been shown to enhance the resistance of plants to fungal and bacterial pathogens. Here, the effect of potassium silicate was assessed on two cotton (Gossypium hirsutum) cultivars subsequently inoculated with Fusarium oxysporum f. sp. vasinfectum (Fov). Sicot 189 is moderately resistant whilst Sicot F-1 is the second most resistant commercial cultivar presently available in Australia. Transmission and light microscopy were used to compare cellular modifications in root cells after these different treatments. The accumulation of phenolic compounds and lignin was measured. Cellular alterations including the deposition of electron-dense material, degradation of fungal hyphae and occlusion of endodermal cells were more rapidly induced and more intense in endodermal and vascular regions of Sicot F-1 plants supplied with potassium silicate followed by inoculation with Fov than in similarly treated Sicot 189 plants or in silicate-treated plants of either cultivar not inoculated with Fov. Significantly more phenolic compounds were present at 7 d post-infection (dpi) in root extracts of Sicot F-1 plants treated with potassium silicate followed by inoculation with Fov compared with plants from all other treatments. The lignin concentration at 3 dpi in root material from Sicot F-1 treated with potassium silicate and inoculated with Fov was significantly higher than that from water-treated and inoculated plants. This study demonstrates that silicon treatment can affect cellular defence responses in cotton roots subsequently inoculated with Fov, particularly in Sicot F-1, a cultivar with greater inherent resistance to this pathogen. This suggests that silicon may interact with or initiate defence pathways faster in this cultivar than in the less resistant cultivar. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  12. European defence industry consolidation and domestic procurement bias

    DEFF Research Database (Denmark)

    Kluth, Michael Friederich

    2017-01-01

    How have European cross-border defence industrial mergers and acquisitions affected domestic procurement bias among the major EU powers? This article departs from the findings of Andrew Moravcsik more than two decades ago suggesting that major West European states had no ingrained preferences...... for defence industrial autarchy. When cross-national armament projects were derailed, this could be attributed to political efforts of national defence industrial champions favouring purely domestic projects. As former national champions join pan-European defence groups, their preferences are likely modified......-border defence industry consolidation will be analysed. Procurement bias is assessed in two industry segments characterised by pervasive consolidation....

  13. Families of returned defence force personnel: a changing landscape of challenges.

    Science.gov (United States)

    Berle, David; Steel, Zachary

    2015-08-01

    This paper aims to identify the key challenges experienced by the families of defence force personnel following deployment. We undertook a selective review of four post-deployment challenges to the families of defence force personnel: (1) changes to relationships; (2) changes to family member roles and responsibilities; (3) adjustment of children and parenting challenges; and (4) anger, family conflict and violence. Emerging issues in the area of post-deployment adjustment are also discussed. Empirical studies of post-deployment family adjustment are lacking. Each of the reviewed challenges can contribute to psychological difficulties and precipitate contact with mental health services. The challenges faced by defence force personnel when returning from deployment arise within a family context. Clinicians should thoroughly assess these factors in families following deployment, but also recognise family strengths and resilience to these challenges. © The Royal Australian and New Zealand College of Psychiatrists 2015.

  14. Integrating Studies on Plant-Pollinator and Plant-Herbivore Interactions

    NARCIS (Netherlands)

    Lucas-Barbosa, Dani

    2016-01-01

    Research on herbivore-induced plant defence and research on pollination ecology have had a long history of separation. Plant reproduction of most angiosperm species is mediated by pollinators, and the effects of herbivore-induced plant defences on pollinator behaviour have been largely neglected.

  15. The response of Acacia karroo plants to defoliation by hand ...

    African Journals Online (AJOL)

    Shoot production of all plants defoliated by hand was no different to that of the undefoliated control plants and was considerably less than that of the plants defoliated by goats. Keywords: acacia karroo; browse production; browsing; clipping; defoliation; goats; growth stimulation; leaf growth; leaves; shoot growth; shoot ...

  16. Integrating nitric oxide into salicylic acid and jasmonic acid/ethylene plant defense pathways

    DEFF Research Database (Denmark)

    Mur, Luis A J; Prats, Elena; Pierre, Sandra

    2013-01-01

    to be tailored to particular biotic stresses. Nitric oxide (NO) has emerged as a major signal influencing resistance mediated by both signalling pathways but no attempt has been made to integrate NO into established SA/JA/ET interactions. NO has been shown to act as an inducer or suppressor of signalling along......Plant defence against pests and pathogens is known to be conferred by either salicylic acid (SA) or jasmonic acid (JA)/ethylene (ET) pathways, depending on infection or herbivore-grazing strategy. It is well attested that SA and JA/ET pathways are mutually antagonistic allowing defence responses...

  17. The Role of Tomato WRKY Genes in Plant Responses to Combined Abiotic and Biotic Stresses

    Directory of Open Access Journals (Sweden)

    Yuling Bai

    2018-06-01

    Full Text Available In the field, plants constantly face a plethora of abiotic and biotic stresses that can impart detrimental effects on plants. In response to multiple stresses, plants can rapidly reprogram their transcriptome through a tightly regulated and highly dynamic regulatory network where WRKY transcription factors can act as activators or repressors. WRKY transcription factors have diverse biological functions in plants, but most notably are key players in plant responses to biotic and abiotic stresses. In tomato there are 83 WRKY genes identified. Here we review recent progress on functions of these tomato WRKY genes and their homologs in other plant species, such as Arabidopsis and rice, with a special focus on their involvement in responses to abiotic and biotic stresses. In particular, we highlight WRKY genes that play a role in plant responses to a combination of abiotic and biotic stresses.

  18. Maize response to time of nitrogen application and planting seasons

    Directory of Open Access Journals (Sweden)

    Parbati Adhikari

    2016-12-01

    Full Text Available Nitrogen (N response by maize differs due to growing seasons, growth stages, duration and growing domain as N losses is higher due to leaching as well as volatilization. Objective of this study was to know the response of split applications of N and growing seasons on maize under Chitwan environments. Field experiments were conducted for two consecutive years at the research field of NMRP Rampur during the winter, spring, and summer seasons of 2012/013 and 2013/014. Experiments were laid out in factorial randomized complete block design with four replications for all the seasons. Early maturing maize genotype Arun-1 EV was used for the experiments. Five splits of recommended dose of N were tested. Grain yield, days to flowering, plant height, ear height, kernel rows per ear, no. of kernels per row, ear length and thousand grain weight significantly differed due to growing seasons and split applications of N. Significantly higher grain yield (3911 kg ha-1 was obtained with the application of 30 kg N ha-1 each at 30, 45, 60, and 75 days after sowing as compared to control (2801 kg ha-1. Regarding the growing seasons, highest grain yield was obtained in winter (4393 kg ha-1 followed by spring (3791 kg ha-1 and summer (2468 kg ha-1 season, respectively. Results of these studies revealed that four splits of N viz. application of 30 kg N each at 30, 45, 60, and 75 days after sowing respectively, would be more economical to minimize N losses from the soil and efficient use of N at critical growth and development stages of maize.

  19. Defence-in-depth concept for the EU-ABWR

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, Hiroshi; Fuchs, Steffen; Takada, Toshiaki; Kataoka, Kazuyoshi [Toshiba International Limited (Japan)

    2013-07-01

    The current defence-in-depth (DiD) concept has been established by the Reactor Harmonization Working Group (RHWG) of Western European Nuclear Regulators Association (WENRA). Principally the DiD concept was already part of the very early power reactor designs. However, additional considerations have been done in order to take plant conditions into account which are beyond the original design basis. The most recent advancements have been done based on major lessons learned from the Fukushima Dai-Ichi accident. Especially for new nuclear reactors it has to be demonstrated that DiD aspects have been considered in their design. Currently Toshiba is adapting its Advanced Boiling Water Reactor (ABWR) for the European market, at first in Finland. This presentation aims to describe how the new DiD concept has been applied to achieve the safety goals for a modern reactor type and to ensure a design that can be licensed in Western Europe. (orig.)

  20. Differential modulation of plant immune responses by diverse members of the Pseudomonas savastanoi pv. savastanoi HopAF type III effector family.

    Science.gov (United States)

    Castañeda-Ojeda, M Pilar; López-Solanilla, Emilia; Ramos, Cayo

    2017-06-01

    The Pseudomonas savastanoi pv. savastanoi NCPPB 3335 type III secretion system (T3SS) effector repertoire includes 33 candidates, seven of which translocate into host cells and interfere with plant defences. The present study was performed to investigate the co-existence of both plasmid- and chromosomal-encoded members of the HopAF effector family, HopAF1-1 and HopAF1-2, respectively, in the genome of NCPPB 3335. Here, we show that the HopAF1 paralogues are widely distributed in the Pseudomonas syringae complex, where HopAF1-1 is most similar to the homologues encoded by other P. syringae pathovars infecting woody hosts that belong to phylogroups 1 and 3. We show that the expression of both HopAF1-1 and HopAF-2 is transcriptionally dependent on HrpL and demonstrate their delivery into Nicotiana tabacum leaves. Although the heterologous delivery of either HopAF1-1 or HopAF1-2 significantly suppressed the production of defence-associated reactive oxygen species levels, only HopAF1-2 reduced the levels of callose deposition. Moreover, the expression of HopAF1-2 by functionally effectorless P. syringae pv. tomato DC3000D28E completely inhibited the hypersensitive response in tobacco and significantly increased the competitiveness of the strain in Nicotiana benthamiana. Despite their functional differences, subcellular localization studies reveal that green fluorescent protein (GFP) fusions to either HopAF1-1 or HopAF1-2 are targeted to the plasma membrane when they are expressed in plant cells, a process that is completely dependent on the integrity of their N-myristoylation motif. Our results further support the notion that highly similar T3SS effectors might differentially interact with diverse plant targets, even when they co-localize in the same cell compartment. © 2016 BSPP AND JOHN WILEY & SONS LTD.

  1. The European Security and Defence Policy

    DEFF Research Database (Denmark)

    Adler-Nissen, Rebecca

    2009-01-01

    The European Security and Defence Policy (ESDP), which is the operational military and civilian dimension of the Common Foreign and Security Policy (CFSP), is today one of the most dynamic areas of the European Union. However, it is only recently that the EU has acquired explicit military decision....... The Union is thus gradually emerging as an important player on the international scene, with a strategic vision, as well as diplomatic, civilian and military crisis-management instruments that complement the existing economic, commercial, humanitarian and development policies on which the EU has hitherto...... built its reputation as a ‘soft power'. Despite its rapid development, many still regard the EU as weak and ineffi cient when it comes to security and defence policy. Moreover, the EU struggles with internal divisions and has a strained relationship with NATO. Nonetheless, there are good reasons...

  2. The Kassel concept for river flood defence

    Energy Technology Data Exchange (ETDEWEB)

    Toensmann, F. [Kassel Univ. (Germany). Dept. of Hydraulic and Water-Resources Engineering

    2000-07-01

    Following an introduction referring to the history, the regulation of ''interference and compensation'' and the ''sustainable development'' as the foundation of future-oriented flood defence concepts are dealt with. The position of science and technology with respect to the employed planning methods: Models for the determination of spatial and temporal distribution of maximum precipitation, river basin models, methods for water level computation, benefit/cost analysis and environmental assessment are described and evaluated. Thereafter the Kassel Concept for River Flood Defence is presented. The basic principle is a mosaic of de-central, semi-central and central measures with reference to the specific project which are economically eligible and environment-compatible. (orig.)

  3. Response of native insect communities to invasive plants.

    Science.gov (United States)

    Bezemer, T Martijn; Harvey, Jeffrey A; Cronin, James T

    2014-01-01

    Invasive plants can disrupt a range of trophic interactions in native communities. As a novel resource they can affect the performance of native insect herbivores and their natural enemies such as parasitoids and predators, and this can lead to host shifts of these herbivores and natural enemies. Through the release of volatile compounds, and by changing the chemical complexity of the habitat, invasive plants can also affect the behavior of native insects such as herbivores, parasitoids, and pollinators. Studies that compare insects on related native and invasive plants in invaded habitats show that the abundance of insect herbivores is often lower on invasive plants, but that damage levels are similar. The impact of invasive plants on the population dynamics of resident insect species has been rarely examined, but invasive plants can influence the spatial and temporal dynamics of native insect (meta)populations and communities, ultimately leading to changes at the landscape level.

  4. The Critical Role of Potassium in Plant Stress Response

    Directory of Open Access Journals (Sweden)

    Min Wang

    2013-04-01

    Full Text Available Agricultural production continues to be constrained by a number of biotic and abiotic factors that can reduce crop yield quantity and quality. Potassium (K is an essential nutrient that affects most of the biochemical and physiological processes that influence plant growth and metabolism. It also contributes to the survival of plants exposed to various biotic and abiotic stresses. The following review focuses on the emerging role of K in defending against a number of biotic and abiotic stresses, including diseases, pests, drought, salinity, cold and frost and waterlogging. The availability of K and its effects on plant growth, anatomy, morphology and plant metabolism are discussed. The physiological and molecular mechanisms of K function in plant stress resistance are reviewed. This article also evaluates the potential for improving plant stress resistance by modifying K fertilizer inputs and highlights the future needs for research about the role of K in agriculture.

  5. Response of a Sphagnum bog plant community to elevated CO2 and N supply

    NARCIS (Netherlands)

    Heijmans, M.M.P.D.; Klees, H.; Visser, de W.; Berendse, F.

    2002-01-01

    The response of plant growth to rising CO2 levels appears to depend on nutrient availability, but it is not known whether the growth of bog plants reacts similarly. We therefore studied the effects of elevated CO2 in combination with N supply on the growth of Sphagnum mosses and vascular plants in

  6. The molecular mechanism of zinc and cadmium stress response in plants

    NARCIS (Netherlands)

    Lin, Y.F.; Aarts, M.G.M.

    2012-01-01

    When plants are subjected to high metal exposure, different plant species take different strategies in response to metal-induced stress. Largely, plants can be distinguished in four groups: metal-sensitive species, metal-resistant excluder species, metal-tolerant non-hyperaccumulator species, and

  7. High productivity of wheat intercropped with maize is associated with plant architectural responses

    NARCIS (Netherlands)

    Zhu, J.; Werf, van der W.; Vos, J.; Putten, van der P.E.L.; Evers, J.B.

    2016-01-01

    Mixed cultivation of crops often results in increased production per unit land area, but the underlying mechanisms are poorly understood. Plants in intercrops grow differently from plants in single crops; however, no study has shown the association between plant plastic responses and the yield

  8. Differential responses of soil bacteria, fungi, archaea and protists to plant species richness and plant functional group identity.

    Science.gov (United States)

    Dassen, Sigrid; Cortois, Roeland; Martens, Henk; de Hollander, Mattias; Kowalchuk, George A; van der Putten, Wim H; De Deyn, Gerlinde B

    2017-08-01

    Plants are known to influence belowground microbial community structure along their roots, but the impacts of plant species richness and plant functional group (FG) identity on microbial communities in the bulk soil are still not well understood. Here, we used 454-pyrosequencing to analyse the soil microbial community composition in a long-term biodiversity experiment at Jena, Germany. We examined responses of bacteria, fungi, archaea, and protists to plant species richness (communities varying from 1 to 60 sown species) and plant FG identity (grasses, legumes, small herbs, tall herbs) in bulk soil. We hypothesized that plant species richness and FG identity would alter microbial community composition and have a positive impact on microbial species richness. Plant species richness had a marginal positive effect on the richness of fungi, but we observed no such effect on bacteria, archaea and protists. Plant species richness also did not have a large impact on microbial community composition. Rather, abiotic soil properties partially explained the community composition of bacteria, fungi, arbuscular mycorrhizal fungi (AMF), archaea and protists. Plant FG richness did not impact microbial community composition; however, plant FG identity was more effective. Bacterial richness was highest in legume plots and lowest in small herb plots, and AMF and archaeal community composition in legume plant communities was distinct from that in communities composed of other plant FGs. We conclude that soil microbial community composition in bulk soil is influenced more by changes in plant FG composition and abiotic soil properties, than by changes in plant species richness per se. © 2017 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

  9. Energetic consequences of an inducible morphological defence in crucian carp.

    Science.gov (United States)

    Pettersson, Lars B; Brönmark, Christer

    1999-10-01

    Crucian carp (Carassius carassius) increases in body depth in response to chemical cues from piscivores and the deeper body constitutes a morphological defence against gape-limited piscivores. In the field, deep-bodied individuals suffer a density-dependent cost when competing with shallow-bodied conspecifics. Here, we use hydrodynamic theory and swimming respirometry to investigate the proposed mechanism underlying this effect, high drag caused by the deep-bodied morphology. Our study confirms that drag is higher for deep-bodied crucian carp, both in terms of estimated theoretical drag and power curve steepness. However, deep-bodied fish swimming at the velocity associated with minimum cost of transport, U mc , did not experience higher costs of transport than shallow-bodied fish. Deep-bodied crucian carp had significantly lower standard metabolic rates, i.e. metabolic rates at rest, and also lower U mc , and the resulting costs of transport were similar for the two morphs. Nevertheless, when deep-bodied individuals deviate from U mc , e.g. when increasing foraging effort under competition, their steeper power curves will cause substantial energy costs relative to shallow-bodied conspecifics. Furthermore, there is evidence that reductions in standard metabolic rate incur costs in terms of lower stress tolerance, reduced growth rate, and life history changes. Thus, this work provides links between hydrodynamics, a cost-reducing mechanism, and a density-dependent fitness cost associated with an inducible defence.

  10. Immune Defence Factors In Human Milk

    Directory of Open Access Journals (Sweden)

    Kumar Sanjeev

    1985-01-01

    Full Text Available Scientific evidence is accumulating to prove the nutritional, anti-infective, anti-fertility, psychosomal and economic advantages of breast-feeding. A number of studies have shown that breast milk protects against diarrheal, respiratory and other infections. Its value in protecting against allergy has also been established. This article reviews the studies on various immune defence factors present in the human milk. The available scientific knowledge makes a very strong case in favour of promoting breast-feeding.

  11. Radiation Protection and Civil defence Department

    International Nuclear Information System (INIS)

    Gomaa, M.A.; Elshinawy, R.M.K.; Abdelfattah, A.T.

    1991-01-01

    This conference involves subjects of radiation protection, programming of civil defence, on the implementation of 1990 ICRP recommendation, thermoluminescence properties of bone equivalent calcium phosphate ceramics, potassium body burdens in occupational users of egyptian nuclear research centre, transport of radionuclides in fresh water stream, water treatment process for nuclear reactor, research activities related to internal contamination and bioassay and experience and environmental radiation monitoring in inshass. it contains of figures and tables

  12. The Man-in-the-Middle Defence

    Science.gov (United States)

    Anderson, Ross; Bond, Mike

    Eliminating middlemen from security protocols helps less than one would think. EMV electronic payments, for example, can be made fairer by adding an electronic attorney - a middleman which mediates access to a customer’s card. We compare middlemen in crypto protocols and APIs with those in the real world, and show that a man-in-the-middle defence is helpful in many circumstances. We suggest that the middleman has been unfairly demonised.

  13. Neurons of self-defence: neuronal innervation of the exocrine defence glands in stick insects.

    Science.gov (United States)

    Stolz, Konrad; von Bredow, Christoph-Rüdiger; von Bredow, Yvette M; Lakes-Harlan, Reinhard; Trenczek, Tina E; Strauß, Johannes

    2015-01-01

    Stick insects (Phasmatodea) use repellent chemical substances (allomones) for defence which are released from so-called defence glands in the prothorax. These glands differ in size between species, and are under neuronal control from the CNS. The detailed neural innervation and possible differences between species are not studied so far. Using axonal tracing, the neuronal innervation is investigated comparing four species. The aim is to document the complexity of defence gland innervation in peripheral nerves and central motoneurons in stick insects. In the species studied here, the defence gland is innervated by the intersegmental nerve complex (ISN) which is formed by three nerves from the prothoracic (T1) and suboesophageal ganglion (SOG), as well as a distinct suboesophageal nerve (Nervus anterior of the suboesophageal ganglion). In Carausius morosus and Sipyloidea sipylus, axonal tracing confirmed an innervation of the defence glands by this N. anterior SOG as well as N. anterior T1 and N. posterior SOG from the intersegmental nerve complex. In Peruphasma schultei, which has rather large defence glands, only the innervation by the N. anterior SOG was documented by axonal tracing. In the central nervous system of all species, 3-4 neuron types are identified by axonal tracing which send axons in the N. anterior SOG likely innervating the defence gland as well as adjacent muscles. These neurons are mainly suboesophageal neurons with one intersegmental neuron located in the prothoracic ganglion. The neuron types are conserved in the species studied, but the combination of neuron types is not identical. In addition, the central nervous system in S. sipylus contains one suboesophageal and one prothoracic neuron type with axons in the intersegmental nerve complex contacting the defence gland. Axonal tracing shows a very complex innervation pattern of the defence glands of Phasmatodea which contains different neurons in different nerves from two adjacent body segments

  14. Are the metabolomic responses to folivory of closely related plant species linked to macroevolutionary and plant-folivore coevolutionary processes?

    Energy Technology Data Exchange (ETDEWEB)

    Rivas-Ubach, Albert [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland Washington 99354 USA; CREAF, Cerdanyola del Vallès 08913 Catalonia Spain; Hódar, José A. [Grupo de Ecología Terrestre, Departamento de Biología Animal y Ecología, Facultad de Ciencias, Universidad de Granada, 18071 Granada Spain; Sardans, Jordi [CREAF, Cerdanyola del Vallès 08913 Catalonia Spain; CSIC, Global Ecology Unit CREAF-CEAB-CSIC-UAB, Cerdanyola del Vallès 08913 Catalonia Spain; Kyle, Jennifer E. [Biological Sciences Division, Pacific Northwest National Laboratory, Richland Washington 99354 USA; Kim, Young-Mo [Biological Sciences Division, Pacific Northwest National Laboratory, Richland Washington 99354 USA; Oravec, Michal [Global Change Research Centre, Academy of Sciences of the Czech Republic, Bĕlidla 4a CZ-603 00 Brno Czech Republic; Urban, Otmar [Global Change Research Centre, Academy of Sciences of the Czech Republic, Bĕlidla 4a CZ-603 00 Brno Czech Republic; Guenther, Alex [Department of Earth System Science, University of California, Irvine California 92697 USA; Peñuelas, Josep [CREAF, Cerdanyola del Vallès 08913 Catalonia Spain; CSIC, Global Ecology Unit CREAF-CEAB-CSIC-UAB, Cerdanyola del Vallès 08913 Catalonia Spain

    2016-06-02

    The debate whether the coevolution of plants and insects or macroevolutionary processes (phylogeny) is the main driver determining the arsenal of molecular defensive compounds of plants remains unresolved. Attacks by herbivorous insects affect not only the composition of defensive compounds in plants but the entire metabolome (the set of molecular metabolites), including defensive compounds. Metabolomes are the final products of genotypes and are directly affected by macroevolutionary processes, so closely related species should have similar metabolomic compositions and may respond in similar ways to attacks by folivores. We analyzed the elemental compositions and metabolomes of needles from Pinus pinaster, P. nigra and P. sylvestris to determine if these closely related Pinus species with different coevolutionary histories with the caterpillars of the processionary moth respond similarly to attacks by this lepidopteran. All pines had different metabolomes and metabolic responses to herbivorous attack. The metabolomic variation among the pine species and the responses to folivory reflected their macroevolutionary relationships, with P. pinaster having the most divergent metabolome. The concentrations of phenolic metabolites were generally not higher in the attacked trees, which had lower concentrations of terpenes, suggesting that herbivores avoid individuals with high concentrations of terpenes. Our results suggest that macroevolutionary history plays important roles in the metabolomic responses of these pine species to folivory, but plant-insect coevolution probably constrains those responses. Combinations of different evolutionary factors and trade-offs are likely responsible for the different responses of each species to folivory, which is not necessarily exclusively linked to plant-insect coevolution.

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

    NARCIS (Netherlands)

    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

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

    Science.gov (United States)

    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

  17. Responses of northern forest plants to atmospheric changes

    Energy Technology Data Exchange (ETDEWEB)

    Laine, K.; Huttunen, S.; Kauppi, M.; Ohtonen, R.; Laehdesmaeki, P. [Oulu Univ. (Finland). Dept. of Biology

    1996-12-31

    This research programme has been under way since 1990 to study the long-term synergistic effects of air pollutants and changing climatic conditions on the northern forest ecosystem and to increase the knowledge of climatic change and its consequences for the fragile northern nature. Ecological, physiological, morphological and biochemical methods have been used to study the responses of forest trees, dwarf shrubs, lichens and soil biology to environmental changes. The research programme is divided into four subprojects concentrating on different ecosystem levels. The subprojects are: (1) life, growth and survival strategies of northern dwarf shrubs under the pressure of a changing environment, (2) forest trees under the impact of air pollutants, increasing CO{sub 2} and UV-B, (3) susceptibility of lichens to air pollution and climatic change and (4) impact of elevated atmospheric CO{sub 2} and O{sub 3} on soil biology with special reference to carbon allocation and N fixation in symbiotic systems. This report summarizes the results of short-term experiments which showed many ecological and physiological changes in almost all elements of the northern boreal forests. These species-level measurements focused on the key species of the northern boreal forest, which have been thought to be useful in large-scale ecosystem experiments and modelling. The results will also facilitate the further studies on the patterns of plant species distribution and northern ecosystem function with respect to the environmental parameters that are expected to change along with global change (e.g. temperature, airchemistry, UV-B, snow condition)

  18. Responses of northern forest plants to atmospheric changes

    Energy Technology Data Exchange (ETDEWEB)

    Laine, K; Huttunen, S; Kauppi, M; Ohtonen, R; Laehdesmaeki, P [Oulu Univ. (Finland). Dept. of Biology

    1997-12-31

    This research programme has been under way since 1990 to study the long-term synergistic effects of air pollutants and changing climatic conditions on the northern forest ecosystem and to increase the knowledge of climatic change and its consequences for the fragile northern nature. Ecological, physiological, morphological and biochemical methods have been used to study the responses of forest trees, dwarf shrubs, lichens and soil biology to environmental changes. The research programme is divided into four subprojects concentrating on different ecosystem levels. The subprojects are: (1) life, growth and survival strategies of northern dwarf shrubs under the pressure of a changing environment, (2) forest trees under the impact of air pollutants, increasing CO{sub 2} and UV-B, (3) susceptibility of lichens to air pollution and climatic change and (4) impact of elevated atmospheric CO{sub 2} and O{sub 3} on soil biology with special reference to carbon allocation and N fixation in symbiotic systems. This report summarizes the results of short-term experiments which showed many ecological and physiological changes in almost all elements of the northern boreal forests. These species-level measurements focused on the key species of the northern boreal forest, which have been thought to be useful in large-scale ecosystem experiments and modelling. The results will also facilitate the further studies on the patterns of plant species distribution and northern ecosystem function with respect to the environmental parameters that are expected to change along with global change (e.g. temperature, airchemistry, UV-B, snow condition)

  19. Plant survival in a changing environment: the role of nitric oxide in plant responses to abiotic stress

    Directory of Open Access Journals (Sweden)

    Marcela eSimontacchi

    2015-11-01

    Full Text Available Nitric oxide in plants may originate endogenously or come from surrounding atmosphere and soil. Interestingly, this gaseous free radical is far from having a constant level and varies greatly among tissues depending on a given plant´s ontogeny and environmental fluctuations.Proper plant growth, vegetative development, and reproduction require the integration of plant hormonal activity with the antioxidant network, as well as the maintenance of concentration of reactive oxygen and nitrogen species within a narrow range. Plants are frequently faced with abiotic stress conditions such as low nutrient availability, salinity, drought, high ultraviolet (UV radiation and extreme temperatures, which can influence developmental processes and lead to growth restriction making adaptive responses the plant´s priority. The ability of plants to respond and survive under environmental-stress conditions involves sensing and signalling events where nitric oxide becomes a critical component mediating hormonal actions, interacting with reactive oxygen species, and modulating gene expression and protein activity. This review focuses on the current knowledge of the role of nitric oxide in adaptive plant responses to some specific abiotic stress conditions, particularly low mineral nutrient supply, drought, salinity and high UV-B radiation.

  20. Response of False horn plantain to different plant densities and ...

    African Journals Online (AJOL)

    The study, which was carried out at the Crops Research Institute, Kumasi, Ghana, from April 1992 to March 1995, aimed at determining (i) the optimum plant density of False horn plantain for maximum yield, and (ii) the optimum frequency of handweeding for economic returns. Results indicated that the optimum plant density ...

  1. Plant species responses to oil degradation and toxicity reduction in ...

    African Journals Online (AJOL)

    Vegetated plots were established by planting different plant species – legumes and vegetable (Abelmoschus, esculentus, Telfaria occidentalis and Vigna unguiculata) and applied with sawdust and chromolaena leaves at different intensities of oil pollution. Toxicity of the soil was evaluated using germination percentage, ...

  2. Photosynthesis and photoprotective systems of plants in response to ...

    African Journals Online (AJOL)

    Aluminum (Al) toxicity is the major factor limiting plant growth in acidic soils, which comprise up to 70% of the world's potentially arable lands. Although, Al toxicity and tolerance in plant roots have been extensively studied during the past decades because inhibition of root growth is one of the earliest symptoms of Al injury ...

  3. Phytoseiulus persimilis response to herbivore-induced plant volatiles as a function of mite-days.

    Science.gov (United States)

    Nachappa, Punya; Margolies, David C; Nechols, James R; Loughin, Thomas

    2006-01-01

    The predatory mite, Phytoseiulus persimilis (Acari: Phytoseiidae), uses plant volatiles (i.e., airborne chemicals) triggered by feeding of their herbivorous prey, Tetranychus urticae (Acari: Tetranychidae), to help locate prey patches. The olfactory response of P. persimilis to prey-infested plants varies in direct relation to the population growth pattern of T. urticae on the plant; P. persimilis responds to plants until the spider mite population feeding on a plant collapses, after which infested plants do not attract predators. It has been suggested that this represents an early enemy-free period for T. urticae before the next generation of females is produced. We hypothesize that the mechanism behind the diminished response of predators is due to extensive leaf damage caused by T. urticae feeding, which reduces the production of volatiles irrespective of the collapse of T. urticae population on the plant. To test this hypothesis we investigated how the response of P. persimilis to prey-infested plants is affected by: 1) initial density of T. urticae, 2) duration of infestation, and 3) corresponding leaf damage due to T. urticae feeding. Specifically, we assessed the response of P. persimilis to plants infested with two T. urticae densities (20 or 40 per plant) after 2, 4, 6, 8, 10, 12 or 14 days. We also measured leaf damage on these plants. We found that predator response to T. urticae-infested plants can be quantified as a function of mite-days, which is a cumulative measure of the standing adult female mite population sampled and summed over time. That is, response to volatiles increased with increasing numbers of T. urticae per plant or with the length of time plant was infested by T. urticae, at least as long at the leaves were green. Predatory mites were significantly attracted to plants that were infested for 2 days with only 20 spider mites. This suggests that the enemy-free period might only provide a limited window of opportunity for T. urticae

  4. The mirror has two faces: dissociative identity disorder and the defence of pathological criminal incapacity--a South African criminal law perspective.

    Science.gov (United States)

    Stevens, Philip

    2013-03-01

    Dissociative identity disorder poses numerous medico legal issues whenever the insanity defence emerges. Within the context of the South African criminal law, the impact of dissociative identity disorder on criminal responsibility has only been addressed very briefly in one decided case. Various questions arise as to the impact that the distinctive diagnostic features of dissociative identity disorder could possibly have on the defence of pathological criminal incapacity, or better known as the insanity defence, within the ambit of the South African criminal law. In this contribution the author reflects on the mental disorder known as dissociative identity disorder or multiple personality disorder, against the backdrop of the defence of pathological criminal incapacity. Reflections are also provided pertaining to the various medico legal issues at stake whenever this defence has to be adjudicated upon.

  5. A detection method in living plant cells for rapidly monitoring the response of plants to exogenous lanthanum.

    Science.gov (United States)

    Cheng, Mengzhu; Wang, Lihong; Yang, Qing; Huang, Xiaohua

    2018-08-30

    The pollution of rare earth elements (REEs) in ecosystem is becoming more and more serious, so it is urgent to establish methods for monitoring the pollution of REEs. Monitoring environmental pollution via the response of plants to pollutants has become the most stable and accurate method compared with traditional methods, but scientists still need to find the primary response of plants to pollutants to improve the sensitivity and speed of this method. Based on the facts that the initiation of endocytosis is the primary cellular response of the plant leaf cells to REEs and the detection of endocytosis is complex and expensive, we constructed a detection method in living plant cells for rapidly monitoring the response of plants to exogenous lanthanum [La(III), a representative of REEs] by designing a new immuno-electrochemical method for detecting the content change in extracellular vitronectin-like protein (VN) that are closely related to endocytosis. Results showed that when 30 μM La(III) initiated a small amount of endocytosis, the content of extracellular VN increased by 5.46 times, but the structure and function of plasma membrane were not interfered by La(III); when 80 μM La(III) strongly initiated a large amount of endocytosis, the content of extracellular VN increased by 119 times, meanwhile, the structure and function of plasma membrane were damaged. In summary, the detection method can reflect the response of plants to La(III) via detecting the content change in extracellular VN, which provides an effective and convenient way to monitor the response of plants to exogenous REEs. Copyright © 2018. Published by Elsevier Inc.

  6. Herbivory and eutrophication mediate grassland plant nutrient responses across a global climatic gradient

    Science.gov (United States)

    Anderson, T. Michael; Griffith, Daniel M.; Grace, James B.; Lind, Eric M.; Adler, Peter B.; Biederman, Lori A.; Blumenthal, Dana M.; Daleo, Pedro; Firn, Jennifer; Hagenah, Nicole; Harpole, W. Stanley; MacDougall, Andrew S.; McCulley, Rebecca L.; Prober, Suzanne M.; Risch, Anita C.; Sankaran, Mahesh; Schütz, Martin; Seabloom, Eric W.; Stevens, Carly J.; Sullivan, Lauren; Wragg, Peter; Borer, Elizabeth T.

    2018-01-01

    Plant stoichiometry, the relative concentration of elements, is a key regulator of ecosystem functioning and is also being altered by human activities. In this paper we sought to understand the global drivers of plant stoichiometry and compare the relative contribution of climatic vs. anthropogenic effects. We addressed this goal by measuring plant elemental (C, N, P and K) responses to eutrophication and vertebrate herbivore exclusion at eighteen sites on six continents. Across sites, climate and atmospheric N deposition emerged as strong predictors of plot‐level tissue nutrients, mediated by biomass and plant chemistry. Within sites, fertilization increased total plant nutrient pools, but results were contingent on soil fertility and the proportion of grass biomass relative to other functional types. Total plant nutrient pools diverged strongly in response to herbivore exclusion when fertilized; responses were largest in ungrazed plots at low rainfall, whereas herbivore grazing dampened the plant community nutrient responses to fertilization. Our study highlights (1) the importance of climate in determining plant nutrient concentrations mediated through effects on plant biomass, (2) that eutrophication affects grassland nutrient pools via both soil and atmospheric pathways and (3) that interactions among soils, herbivores and eutrophication drive plant nutrient responses at small scales, especially at water‐limited sites.

  7. The COP9 signalosome controls jasmonic acid synthesis and plant responses to herbivory and pathogens.

    Science.gov (United States)

    Hind, Sarah R; Pulliam, Sarah E; Veronese, Paola; Shantharaj, Deepak; Nazir, Azka; Jacobs, Nekaiya S; Stratmann, Johannes W

    2011-02-01

    The COP9 signalosome (CSN) is a multi-protein complex that regulates the activities of cullin-RING E3 ubiquitin ligases (CRLs). CRLs ubiquitinate proteins in order to target them for proteasomal degradation. The CSN is required for proper plant development. Here we show that the CSN also has a profound effect on plant defense responses. Silencing of genes for CSN subunits in tomato plants resulted in a mild morphological phenotype and reduced expression of wound-responsive genes in response to mechanical wounding, attack by Manduca sexta larvae, and Prosystemin over-expression. In contrast, expression of pathogenesis-related genes was increased in a stimulus-independent manner in these plants. The reduced wound response in CSN-silenced plants corresponded with reduced synthesis of jasmonic acid (JA), but levels of salicylic acid (SA) were unaltered. As a consequence, these plants exhibited reduced resistance against herbivorous M. sexta larvae and the necrotrophic fungal pathogen Botrytis cinerea. In contrast, susceptibility to tobacco mosaic virus (TMV) was not altered in CSN-silenced plants. These data demonstrate that the CSN orchestrates not only plant development but also JA-dependent plant defense responses. © 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.

  8. An evaluation of the defence in depth concept in the light of the Three Mile Island accident

    International Nuclear Information System (INIS)

    Fuchs, H.; Gibbs, K.P.

    1981-01-01

    One of the fundamental bases of reactor safety has been the 'defence in depth' concept. Valuable lessons for plants outside the USA can be learned by studying both the strengths and weaknesses of all the various lines of defence in the light of the TMI findings. These lessons can be summarized as follows: Quality: lack of quality led to the initiation of the event through frequent trips, one of which eventually led to the sticking open of the PORV. It also led to wrong diagnosis of the fault. Multiple failures during the many hours the incident lasted distracted the operator and made a careful diagnosis of its causes and progress impossible. Reactor protection system: the Babcock and Wilcox PWR, with its once-through steam generators (OTSG), responds more rapidly than other LWRs to some operating transients. This does not necessarily result in a less safe system provided that the reactor protection system is designed with the fast response in mind, e.g. by providing anticipatory trips. This emphasizes the importance of a systems approach to design rather than too much reliance on codes and standards, which may not recognize important plant differences. Safety systems: For similar reasons the low water content of the OTSG could have been compensated for by a higher reliability in the emergency feed system. In US practice the operator plays an important role in aligning safety systems, whereas in Europe there is more extensive automation. The latter system leads to an analysis of a wider spectrum of faults to ensure that the automatics respond correctly in all circumstances. Containment: The TMI incident showed that the containment can be very valuable for situations where far more core damage and hydrogen production occurs than is predicted for design basis accidents. Continuing containment integrity depends on core cooling and on the correct operation or isolation of many other systems, whose role in such accidents has not always been recognized

  9. Comparative effect of ZnO NPs, ZnO bulk and ZnSO4 in the antioxidant defences of two plant species growing in two agricultural soils under greenhouse conditions.

    Science.gov (United States)

    García-Gómez, Concepción; Obrador, Ana; González, Demetrio; Babín, Mar; Fernández, María Dolores

    2017-07-01

    The present study has investigated the toxicity of ZnO NPs to bean (Phaseolus vulgaris) and tomato (Solanum lycopersicon) crops grown to maturity under greenhouse conditions using an acidic (soil pH5.4) and a calcareous soil (soil pH8.3). The potentially available Zn in the soils and the Zn accumulation in the leaves from NPs applied to the soil (3, 20 and 225mgZnkg -1 ) and changes in the chlorophylls, carotenoids and oxidative stress biomarkers were measured at 15, 30, 60 and 90days and compared with those caused by bulk ZnO and ZnSO 4 . The available Zn in the soil and the leaf Zn content did not differ among the Zn chemical species, except in the acidic soil at the highest concentration of Zn applied as Zn ions, where the highest values of the two variables were found. The ZnO NPs showed comparable Zn toxicity or biostimulation to their bulk counterparts and Zn salts, irrespective of certain significant differences suggesting a higher activity of the Zn ion. The treatments altered the photosynthetic pigment concentration and induced oxidative stress in plants. ROS formation was observed at Zn plant concentrations ranging from 590 to 760mgkg -1 , but the effects on the rest of the parameters were highly dependent on the plant species, exposure time and especially soil type. In general, the effects were higher in the acidic soil than in the calcareous soil for the bean and the opposite for the tomato. The similar uptakes and toxicities of the different Zn forms suggest that the Zn ions derived from the ZnO NPs exerted a preferential toxicity in plants. However, several results obtained in soils treated with NPs at 3mgZnkg -1 soil indicated that may exist other underlying mechanisms related to the intrinsic nanoparticle properties, especially at low NP concentrations. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Reinforcement of Defence-in-Depth: Modification Practice After the Fukushima Nuclear Accident

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y.; Tang, H.; Mao, Q., E-mail: wangyuhong@cgnpc.com.cn [China Nuclear Power Design Co., Ltd Xia Meilin, Futian District, Shenzhen, Guangdong Province (China)

    2014-10-15

    The Fukushima Daiichi nuclear accident revealed the importance and demand for further reinforcement of defence in- depth. CGN (China General Nuclear Power Group) has made a complete safety assessment on CPR1000 nuclear power plants under construction in China. Dozens of modifications have been implemented based on the assessment findings and lessons learned from Fukushima nuclear accident, taking into account of PSA (Probabilistic Safety Analysis) and comparison analysis of the latest regulations and standards. These modifications help to enhance nuclear safety significantly for nuclear power plants under construction in China, and provide helpful modification guidance for nuclear power plants in operation of the same type. (author)

  11. Plant responses to precipitation in desert ecosystems: integrating functional types, pulses, thresholds, and delays.

    Science.gov (United States)

    Ogle, Kiona; Reynolds, James F

    2004-10-01

    The 'two-layer' and 'pulse-reserve' hypotheses were developed 30 years ago and continue to serve as the standard for many experiments and modeling studies that examine relationships between primary productivity and rainfall variability in aridlands. The two-layer hypothesis considers two important plant functional types (FTs) and predicts that woody and herbaceous plants are able to co-exist in savannas because they utilize water from different soil layers (or depths). The pulse-reserve model addresses the response of individual plants to precipitation and predicts that there are 'biologically important' rain events that stimulate plant growth and reproduction. These pulses of precipitation may play a key role in long-term plant function and survival (as compared to seasonal or annual rainfall totals as per the two-layer model). In this paper, we re-evaluate these paradigms in terms of their generality, strengths, and limitations. We suggest that while seasonality and resource partitioning (key to the two-layer model) and biologically important precipitation events (key to the pulse-reserve model) are critical to understanding plant responses to precipitation in aridlands, both paradigms have significant limitations. Neither account for plasticity in rooting habits of woody plants, potential delayed responses of plants to rainfall, explicit precipitation thresholds, or vagaries in plant phenology. To address these limitations, we integrate the ideas of precipitation thresholds and plant delays, resource partitioning, and plant FT strategies into a simple 'threshold-delay' model. The model contains six basic parameters that capture the nonlinear nature of plant responses to pulse precipitation. We review the literature within the context of our threshold-delay model to: (i) develop testable hypotheses about how different plant FTs respond to pulses; (ii) identify weaknesses in the current state-of-knowledge; and (iii) suggest future research directions that will

  12. Evaluating physiological responses of plants to salinity stress

    KAUST Repository

    Negrã o, Só nia; Schmö ckel, S. M.; Tester, Mark A.

    2016-01-01

    Background Because soil salinity is a major abiotic constraint affecting crop yield, much research has been conducted to develop plants with improved salinity tolerance. Salinity stress impacts many aspects of a plant’s physiology, making

  13. Plant's adaptive response under UV-B-radiation influence

    International Nuclear Information System (INIS)

    Danil'chenko, O.A.; Grodzinskij, D.M.

    2002-01-01

    Reduction of ozone layer, owing to anthropogenic contamination of an atmosphere results in increase of intensity of UV-radiation and shift of its spectrum in the short-wave side that causes strengthening of various biological effects of irradiation. Consequences of these processes may include increase of injuring of plants and decrease of productivity of agricultural crops to increased UV levels. The important significance in the plant's adaptation to different unfavorable factors has the plant's radioadaptive answer. It has been shown that radioadaptation of plants occurred not only after irradiation with g-radiation in low doses but after UV-rays action . Reaction of radioadaptation it seems to be nonspecific phenomenon in relation to type radiations

  14. Plant growth enhancement and associated physiological responses are coregulated by ethylene and gibberellin in response to harpin protein Hpa1.

    Science.gov (United States)

    Li, Xiaojie; Han, Bing; Xu, Manyu; Han, Liping; Zhao, Yanying; Liu, Zhilan; Dong, Hansong; Zhang, Chunling

    2014-04-01

    The harpin protein Hpa1 produced by the bacterial blight pathogen of rice induces several growth-promoting responses in plants, activating the ethylene signaling pathway, increasing photosynthesis rates and EXPANSIN (EXP) gene expression levels, and thereby enhancing the vegetative growth. This study was attempted to analyze any mechanistic connections among the above and the role of gibberellin in these responses. Hpa1-induced growth enhancement was evaluated in Arabidopsis, tomato, and rice. And growth-promoting responses were determined mainly as an increase of chlorophyll a/b ratio, which indicates a potential elevation of photosynthesis rates, and enhancements of photosynthesis and EXP expression in the three plant species. In Arabidopsis, Hpa1-induced growth-promoting responses were partially compromised by a defect in ethylene perception or gibberellin biosynthesis. In tomato and rice, compromises of Hpa1-induced growth-promoting responses were caused by a pharmacological treatment with an ethylene perception inhibitor or a gibberellin biosynthesis inhibitor. In the three plant species, moreover, Hpa1-induced growth-promoting responses were significantly impaired, but not totally eliminated, by abolishing ethylene perception or gibberellin synthesis. However, simultaneous nullifications in both ethylene perception and gibberellin biosynthesis almost canceled the full effects of Hpa1 on plant growth, photosynthesis, and EXP2 expression. Theses results suggest that ethylene and gibberellin coregulate Hpa1-induced plant growth enhancement and associated physiological and molecular responses.

  15. Differential response of plants to aluminum. A review

    OpenAIRE

    Valencia R, Rubén A; Ligarreto M, Gustavo A

    2012-01-01

    Aluminum toxicity is a major limiting factor to the growth and development of plants in acidic soils worldwide, occurring in 40% of arable soils. The root seems to be the object of aluminum toxicity, particularly the apex, producing a rapid inhibition of cell division and elongation of the root. Fortunately, plants differ in their ability to tolerate aluminum and grow in acidic soils. Tolerance mechanisms have commonly been defined in genetic and physiological terms, however, tolerance mechan...

  16. Differential responses of onion and garlic against plant growth regulators

    International Nuclear Information System (INIS)

    Oozunidou, G.; Asif, M.; Giannakuola, A.; Iliass, A.

    2011-01-01

    The effects of Gibberellic acid-GA3, Prohexadione-Calcium, and Ethephon pre-harvest application on yield, biomass production, photosynthetic function, lipid peroxidation and quality characteristics of onion (Allium cepa L.) and garlic (Allium sativum L.) plants were investigated. Shoot length and biomass of onion and garlic, expressed either in fresh or dry weight, increased significantly under GA3, while a progressive decrease under Prohex-Ca and Ethephon occurred. Higher MDA (lipid peroxidation) values were recorded after Prohex-Ca and Ethephon supply on onion and garlic plants; it seems that GA3 treatment prevents lipid peroxidation as measured with the help of the TBARS method. Plants treated with Prohex-Ca and Ethephon revealed higher peroxidase activity compared to control and GA3 treated plants. Considering the results of MDA content and peroxidase activities it can be assumed that GA3 treated plants are slightly protected from the natural course of oxidative stress, which occurs during ageing as observed for control samples. The fluctuations of chlorophyll fluorescence parameters represent a general decline in chloroplasts function after plant growth regulators exposure, whereas in combination to the suppressed chlorophyll content, structural malformations of photo systems may also occur. The production of ascorbic acid, glucose and fructose content seems to be enhanced under GA3 in both species, while their values were depressed under Prohex-Ca and Ethephon. Overall, only GA3 supply leads to a vigorous onion and garlic growth and yield. (author)

  17. Molecular mimicry modulates plant host responses to pathogens.

    Science.gov (United States)

    Ronald, Pamela; Joe, Anna

    2018-01-25

    Pathogens often secrete molecules that mimic those present in the plant host. Recent studies indicate that some of these molecules mimic plant hormones required for development and immunity. This Viewpoint reviews the literature on microbial molecules produced by plant pathogens that functionally mimic molecules present in the plant host. This article includes examples from nematodes, bacteria and fungi with emphasis on RaxX, a microbial protein produced by the bacterial pathogen Xanthomonas oryzae pv. oryzae. RaxX mimics a plant peptide hormone, PSY (plant peptide containing sulphated tyrosine). The rice immune receptor XA21 detects sulphated RaxX but not the endogenous peptide PSY. Studies of the RaxX/XA21 system have provided insight into both host and pathogen biology and offered a framework for future work directed at understanding how XA21 and the PSY receptor(s) can be differentially activated by RaxX and endogenous PSY peptides. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Plant methyl salicylate induces defense responses in the rhizobacterium Bacillus subtilis.

    Science.gov (United States)

    Kobayashi, Kazuo

    2015-04-01

    Bacillus subtilis is a rhizobacterium that promotes plant growth and health. Cultivation of B. subtilis with an uprooted weed on solid medium produced pleat-like architectures on colonies near the plant. To test whether plants emit signals that affect B. subtilis colony morphology, we examined the effect of plant-related compounds on colony morphology. Bacillus subtilis formed mucoid colonies specifically in response to methyl salicylate, which is a plant-defense signal released in response to pathogen infection. Methyl salicylate induced mucoid colony formation by stimulating poly-γ-glutamic acid biosynthesis, which formed enclosing capsules that protected the cells from exposure to antimicrobial compounds. Poly-γ-glutamic acid synthesis depended on the DegS-DegU two-component regulatory system, which activated DegSU-dependent gene transcription in response to methyl salicylate. Bacillus subtilis did not induce plant methyl salicylate production, indicating that the most probable source of methyl salicylate in the rhizosphere is pathogen-infected plants. Methyl salicylate induced B. subtilis biosynthesis of the antibiotics bacilysin and fengycin, the latter of which exhibited inhibitory activity against the plant pathogenic fungus Fusarium oxysporum. We propose that B. subtilis may sense plants under pathogen attack via methyl salicylate, and express defense responses that protect both B. subtilis and host plants in the rhizosphere. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  19. Plant Perception and Short-Term Responses to Phytophagous Insects and Mites

    Directory of Open Access Journals (Sweden)

    M. Estrella Santamaria

    2018-05-01

    Full Text Available Plant–pest relationships involve complex processes encompassing a network of molecules, signals, and regulators for overcoming defenses they develop against each other. Phytophagous arthropods identify plants mainly as a source of food. In turn, plants develop a variety of strategies to avoid damage and survive. The success of plant defenses depends on rapid and specific recognition of the phytophagous threat. Subsequently, plants trigger a cascade of short-term responses that eventually result in the production of a wide range of compounds with defense properties. This review deals with the main features involved in the interaction between plants and phytophagous insects and acari, focusing on early responses from the plant side. A general landscape of the diverse strategies employed by plants within the first hours after pest perception to block the capability of phytophagous insects to develop mechanisms of resistance is presented, with the potential of providing alternatives for pest control.

  20. Armed rollers: does nestling's vomit function as a defence against predators?

    Directory of Open Access Journals (Sweden)

    Deseada Parejo

    Full Text Available Chemical defences against predators are widespread in the animal kingdom although have been seldom reported in birds. Here, we investigate the possibility that the orange liquid that nestlings of an insectivorous bird, the Eurasian roller (Coracias garrulus, expel when scared at their nests acts as a chemical defence against predators. We studied the diet of nestling rollers and vomit origin, its chemical composition and deterrent effect on a mammal generalist predator. We also hypothesized that nestling rollers, as their main prey (i.e. grasshoppers do from plants, could sequester chemicals from their prey for their use. Grasshoppers, that also regurgitate when facing to a threat, store the harmful substances used by plants to defend themselves against herbivores. We found that nestling rollers only vomit after being grasped and moved. The production of vomit depended on food consumption and the vomit contained two deterrent chemicals (hydroxycinnamic and hydroxybenzoic acids stored by grasshoppers and used by plants to diminish herbivory, suggesting that they originate from the rollers' prey. Finally, we showed for the first time that the oral secretion of a vertebrate had a deterrent effect on a model predator because vomit of nestling rollers made meat distasteful to dogs. These results support the idea that the vomit of nestling rollers is a chemical defence against predators.

  1. Genome-wide identification of potato long intergenic noncoding RNAs responsive to Pectobacterium carotovorum subspecies brasiliense infection.

    Science.gov (United States)

    Kwenda, Stanford; Birch, Paul R J; Moleleki, Lucy N

    2016-08-11

    Long noncoding RNAs (lncRNAs) represent a class of RNA molecules that are implicated in regulation of gene expression in both mammals and plants. While much progress has been made in determining the biological functions of lncRNAs in mammals, the functional roles of lncRNAs in plants are still poorly understood. Specifically, the roles of long intergenic nocoding RNAs (lincRNAs) in plant defence responses are yet to be fully explored. In this study, we used strand-specific RNA sequencing to identify 1113 lincRNAs in potato (Solanum tuberosum) from stem tissues. The lincRNAs are expressed from all 12 potato chromosomes and generally smaller in size compared to protein-coding genes. Like in other plants, most potato lincRNAs possess single exons. A time-course RNA-seq analysis between a tolerant and a susceptible potato cultivar showed that 559 lincRNAs are responsive to Pectobacterium carotovorum subsp. brasiliense challenge compared to mock-inoculated controls. Moreover, coexpression analysis revealed that 17 of these lincRNAs are highly associated with 12 potato defence-related genes. Together, these results suggest that lincRNAs have potential functional roles in potato defence responses. Furthermore, this work provides the first library of potato lincRNAs and a set of novel lincRNAs implicated in potato defences against P. carotovorum subsp. brasiliense, a member of the soft rot Enterobacteriaceae phytopathogens.

  2. Stage-Related Defense Response Induction in Tomato Plants by Nesidiocoris tenuis

    Science.gov (United States)

    Naselli, Mario; Urbaneja, Alberto; Siscaro, Gaetano; Jaques, Josep A.; Zappalà, Lucia; Flors, Víctor; Pérez-Hedo, Meritxell

    2016-01-01

    The beneficial effects of direct predation by zoophytophagous biological control agents (BCAs), such as the mirid bug Nesidiocoris tenuis, are well-known. However, the benefits of zoophytophagous BCAs’ relation with host plants, via induction of plant defensive responses, have not been investigated until recently. To date, only the females of certain zoophytophagous BCAs have been demonstrated to induce defensive plant responses in tomato plants. The aim of this work was to determine whether nymphs, adult females, and adult males of N. tenuis are able to induce defense responses in tomato plants. Compared to undamaged tomato plants (i.e., not exposed to the mirid), plants on which young or mature nymphs, or adult males or females of N. tenuis fed and developed were less attractive to the whitefly Bemisia tabaci, but were more attractive to the parasitoid Encarsia formosa. Female-exposed plants were more repellent to B. tabaci and more attractive to E. formosa than were male-exposed plants. When comparing young- and mature-nymph-exposed plants, the same level of repellence was obtained for B. tabaci, but mature-nymph-exposed plants were more attractive to E. formosa. The repellent effect is attributed to the signaling pathway of abscisic acid, which is upregulated in N. tenuis-exposed plants, whereas the parasitoid attraction was attributed to the activation of the jasmonic acid signaling pathway. Our results demonstrate that all motile stages of N. tenuis can trigger defensive responses in tomato plants, although these responses may be slightly different depending on the stage considered. PMID:27472328

  3. Introducing PCTRAN as an evaluation tool for nuclear power plant emergency responses

    International Nuclear Information System (INIS)

    Cheng, Yi-Hsiang; Shih, Chunkuan; Chiang, Show-Chyuan; Weng, Tung-Li

    2012-01-01

    Highlights: ► PCTRAN is integrated with an atmospheric dispersion algorithm. ► The improved PCTRAN acts as an accident/incident simulator and a data exchange system. ► The software helps the responsible organizations decide the rescue and protective actions. ► The evaluation results show the nuclear power plant accident and its off-site dose consequences. ► The software can be used for nuclear power plant emergency responses. - Abstract: Protecting the public from radiation exposure is important if a nuclear power plant (NPP) accident occurs. Deciding appropriate protective actions in a timely and effective manner can be fulfilled by using an effective accident evaluation tool. In our earlier work, we have integrated PCTRAN (Personal Computer Transient Analyzer) with the off-site dose calculation model. In this study, we introduce PCTRAN as an evaluation tool for nuclear power plant emergency responses. If abnormal conditions in the plant are monitored or observed, the plant staffs can distinguish accident/incident initiation events. Thus, the responsible personnel can immediately operate PCTRAN and set up those accident/incident initiation events to simulate the nuclear power plant transient or accident in conjunction with off-site dose distributions. The evaluation results consequently help the responsible organizations decide the rescue and protective actions. In this study, we explain and demonstrate the capabilities of PCTRAN for nuclear emergency responses, through applying it to simulate the postulated nuclear power plant accident scenarios.

  4. Molecular responses in root-associative rhizospheric bacteria to variations in plant exudates

    Science.gov (United States)

    Abdoun, Hamid; McMillan, Mary; Pereg, Lily

    2015-04-01

    Plant exudates are a major factor in the interface of plant-soil-microbe interactions and it is well documented that the microbial community structure in the rhizosphere is largely influenced by the particular exudates excreted by various plants. Azospirillum brasilense is a plant growth promoting rhizobacterium that is known to interact with a large number of plants, including important food crops. The regulatory gene flcA has an important role in this interaction as it controls morphological differentiation of the bacterium that is essential for attachment to root surfaces. Being a response regulatory gene, flcA mediates the response of the bacterial cell to signals from the surrounding rhizosphere. This makes this regulatory gene a good candidate for analysis of the response of bacteria to rhizospheric alterations, in this case, variations in root exudates. We will report on our studies on the response of Azospirillum, an ecologically, scientifically and agriculturally important bacterial genus, to variations in the rhizosphere.

  5. Molecular signatures in Arabidopsis thaliana in response to insect attack and bacterial infection.

    Science.gov (United States)

    Barah, Pankaj; Winge, Per; Kusnierczyk, Anna; Tran, Diem Hong; Bones, Atle M

    2013-01-01

    Under the threat of global climatic change and food shortages, it is essential to take the initiative to obtain a comprehensive understanding of common and specific defence mechanisms existing in plant systems for protection against different types of biotic invaders. We have implemented an integrated approach to analyse the overall transcriptomic reprogramming and systems-level defence responses in the model plant species Arabidopsis thaliana (A. thaliana henceforth) during insect Brevicoryne brassicae (B. brassicae henceforth) and bacterial Pseudomonas syringae pv. tomato strain DC3000 (P. syringae henceforth) attacks. The main aim of this study was to identify the attacker-specific and general defence response signatures in A. thaliana when attacked by phloem-feeding aphids or pathogenic bacteria. The obtained annotated networks of differentially expressed transcripts indicated that members of transcription factor families, such as WRKY, MYB, ERF, BHLH and bZIP, could be crucial for stress-specific defence regulation in Arabidopsis during aphid and P. syringae attack. The defence response pathways, signalling pathways and metabolic processes associated with aphid attack and P. syringae infection partially overlapped. Components of several important biosynthesis and signalling pathways, such as salicylic acid (SA), jasmonic acid (JA), ethylene (ET) and glucosinolates, were differentially affected during the two the treatments. Several stress-regulated transcription factors were known to be associated with stress-inducible microRNAs. The differentially regulated gene sets included many signature transcription factors, and our co-expression analysis showed that they were also strongly co-expressed during 69 other biotic stress experiments. Defence responses and functional networks that were unique and specific to aphid or P. syringae stresses were identified. Furthermore, our analysis revealed a probable link between biotic stress and microRNAs in Arabidopsis and

  6. Networks and network analysis for defence and security

    CERN Document Server

    Masys, Anthony J

    2014-01-01

    Networks and Network Analysis for Defence and Security discusses relevant theoretical frameworks and applications of network analysis in support of the defence and security domains. This book details real world applications of network analysis to support defence and security. Shocks to regional, national and global systems stemming from natural hazards, acts of armed violence, terrorism and serious and organized crime have significant defence and security implications. Today, nations face an uncertain and complex security landscape in which threats impact/target the physical, social, economic

  7. Plant response-based sensing for control starategies in sustainable greenhouse production

    International Nuclear Information System (INIS)

    Kacira, M.; Sase, S.; Okushima, L.; Ling, P.P.

    2005-01-01

    The effect of environmental variability is one of the major concerns in experimental design for both research in plant systems and greenhouse plant production. Microclimates surrounding plants are not usually uniform. Therefore, many samples and sensors are required to obtain a true representation of the plant population. A plant monitoring system capable of reducing the required number of samples by reducing environmental variability would be more advantageous. To better understand plant-environment interaction, it is essential to study plants, microclimate surrounding the plants and the growth media. To achieve this, the monitoring system must be equipped with proper instrumentation. To achieve proper management practices and sustainable greenhouse production, it is essential first to understand plants and their interactions with their surroundings and then establish plant response-based sensing and control strategies for greenhouse processes. Therefore, an effort was conducted to review and discuss current sensing and control strategies in greenhouse research and plant production and provide recommendations on plant response-based sensing and control strategies for sustainable greenhouse production

  8. Wound-induced proteinase inhibitor in Salix viminalis and its association with defence against insects

    Energy Technology Data Exchange (ETDEWEB)

    Saarikoski, P. [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Forest Genetics

    1997-09-01

    For successful traditional breeding, the plant material has to be screened for genetic variation for the desired traits. By screening Salix clones for wound-induced proteinase inhibitor (PI) activity and ethylene evolution, it was possible to identify variation for both characters among the Salix clones tested. However, no correlation was observed with insect and pathogen resistance. Since there was no simple relationship between wound-induced ethylene production, accumulation of PI and pest resistance, a more systematic investigation of Salix PIs was begun. A gene (swin1.1) encoding a 21 kDa trypsin inhibitor with characteristics of Kunitz-type of PI was sequenced. The trypsin inhibitor encoded by the isolated swin1.1 gene was shown to be functional in vitro and exhibit specificity for trypsin. It is therefore likely that this PI is involved in the plant defence in Salix, since many insects have trypsin as their major digestive protease. In further support of this view, in bio-tests with poplar the mortality of the first instar larvae (Lymantria dispar) was significantly increased, both after application of the trypsin inhibitor encoded by swin1.1 directly on poplar leaves and after feeding the larvae with transgenic poplar over-expressing the swin1.1 gene. In Salix, the swin1.1 gene was shown to be induced by mechanical wounding, insect feeding and by treatment with the signalling substances salicylic and jasmonic acid. The locally wound-induced response (mechanical and insect) was greater than the systemic response. Other swin1 gene family members were also differentially expressed after the inductive treatment. 187 refs., 3 figs., 2 tabs.

  9. Subtle variation in shade avoidance responses may have profound consequences for plant competitiveness.

    Science.gov (United States)

    Bongers, Franca J; Pierik, Ronald; Anten, Niels P R; Evers, Jochem B

    2017-12-21

    Although phenotypic plasticity has been shown to be beneficial for plant competitiveness for light, there is limited knowledge on how variation in these plastic responses plays a role in determining competitiveness. A combination of detailed plant experiments and functional-structural plant (FSP) modelling was used that captures the complex dynamic feedback between the changing plant phenotype and the within-canopy light environment in time and 3-D space. Leaf angle increase (hyponasty) and changes in petiole elongation rates in response to changes in the ratio between red and far-red light, two important shade avoidance responses in Arabidopsis thaliana growing in dense population stands, were chosen as a case study for plant plasticity. Measuring and implementing these responses into an FSP model allowed simulation of plant phenotype as an emergent property of the underlying growth and response mechanisms. Both the experimental and model results showed that substantial differences in competitiveness may arise between genotypes with only marginally different hyponasty or petiole elongation responses, due to the amplification of plant growth differences by small changes in plant phenotype. In addition, this study illustrated that strong competitive responses do not necessarily have to result in a tragedy of the commons; success in competition at the expense of community performance. Together, these findings indicate that selection pressure could probably have played a role in fine-tuning the sensitive shade avoidance responses found in plants. The model approach presented here provides a novel tool to analyse further how natural selection could have acted on the evolution of plastic responses.

  10. Plant response to sunflower seeds to osmotic conditioning

    Directory of Open Access Journals (Sweden)

    Camila Santos Barros de Morais

    2014-10-01

    Full Text Available The aim of this study was to evaluate the effect of seeds osmotic conditioning in seedlings emergence and plants performance of sunflower. Three lots of seeds sunflower (Catissol, was submited to osmotic conditioning with polyethylene glycol solution, –2,0 MPa in aerated system, under 15 ºC for 8 hour and then was evaluated for germination tests and vigour. Under filed conditions was conducted emergency evaluations of seedling, plants development as well as the productivity and seeds quality, and the accumulation of nutrients in the seeds. The osmotic conditioning improve the survival of seedling, the dry matter mass to aerial part of plants from 60 days after sowing and oil content, in lots with low seeds physiological quality. The osmotic conditioning not increase the seeds yield but promotes the vigour of seeds produced, regardless of the lot used for sowing seeds.

  11. Defence and illustration of nuclear deterrence

    International Nuclear Information System (INIS)

    Tertrais, Bruno

    2011-01-01

    After having shown that nuclear deterrence has been efficient since 1945 (nuclear weapons prevented from war, nuclear deterrence contributed to the reduction of risks related to proliferation), the author discusses the amorality and illegality of nuclear deterrence (its ethics can indeed be a matter of discussion, as well as issues like self-defence and international humanitarian law). On another hand, he shows that deterrence costs remain acceptable and that substitutes to nuclear deterrence are not credible. He concludes that deterrence is therefore still useful and legitimate

  12. Chromatin changes in response to drought, salinity, heat, and cold stresses in plants

    Directory of Open Access Journals (Sweden)

    Jong-Myong eKim

    2015-03-01

    Full Text Available Chromatin regulation is essential to regulate genes and genome activities. In plants, the alteration of histone modification and DNA methylation are coordinated with changes in the expression of stress-responsive genes to adapt to environmental changes. Several chromatin regulators have been shown to be involved in the regulation of stress-responsive gene networks under abiotic stress conditions. Specific histone modification sites and the histone modifiers that regulate key stress-responsive genes have been identified by genetic and biochemical approaches, revealing the importance of chromatin regulation in plant stress responses. Recent studies have also suggested that histone modification plays an important role in plant stress memory. In this review, we summarize recent progress on the regulation and alteration of histone modification (acetylation, methylation, phosphorylation, and SUMOylation in response to the abiotic stresses, drought, high-salinity, heat, and cold in plants.

  13. Ionising radiation safety training in the Australian Defence Organisation (ADO)

    International Nuclear Information System (INIS)

    Jenks, G.J.; O'Donovan, E.J.B.; Wood, W.B.

    1998-01-01

    Training personnel in ionising radiation safety within the Australian Defence Organisation (ADO) requires addressing some unique features of an organisation employing both military and civilian personnel. Activities may include those of a civil nature (such as industrial and medical radiography), specific military requirements (for training and emergency response) and scientific research and development. Some personnel may be assigned to full-time duties associated with radiation. However, most are designated as radiation protection officers as a secondary duty. A further complication is that most military personnel are subjected to postings at regular intervals. The ADO's Directorate of Defence Occupational Health and Safety has established an Ionising Radiation Safety Subcommittee to monitor not only the adequacy of the internal Ionising Radiation Safety Manual but also the training requirements. A Training Course, responding to these requirements, has been developed to emphasize, basic radiation theory and protection, operation of radiation monitors available in the ADO, an understanding of the Ionising Radiation Safety Manual, day-to-day radiation safety in units and establishments, and appropriate responses to radiation accidents and emergencies. In addition, students are briefed on a limited number of peripheral topics and participate in some site visits. Currently, two Courses are held annually, each with about twenty students. Most of the material is presented by ADO personnel with external contractor support. The three Courses held to date have proved successful, both for the students and the ADO generally. To seek national accreditation of the course through the Australian National Training Authority, as a first step, competency standards have been proposed. (authors)

  14. Ionising radiation safety training in the Australian defence organisation (ADO)

    International Nuclear Information System (INIS)

    Jenks, G.J.; O'Donovan, E.J.B.; Wood, W.B.

    1996-01-01

    Full text: Training personnel in ionising radiation safety within the Australian Defence Organisation (ADO) requires addressing some unique features of an organisation employing both military and civilian personnel. Activities may include those of a civil nature (such as industrial and medical radiography), specific military requirements (for training and emergency response) and scientific research and development. Some personnel may be assigned to full-time duties associated with radiation, while others may be designated as radiation protection officers in remote units with few duties to perform in this role. A further complication is that most military personnel are subjected to postings at regular intervals. The ADO's Directorate of Defence Occupational Health and Safety has established an Ionising Radiation Safety Subcommittee to monitor not only the adequacy of the internal Ionising Radiation Safety Manual but also the training requirements. A training course, responding to these requirements, has been developed to emphasise: basic radiation theory and protection; operation of radiation monitors available in the ADO; an understanding of the Safety Manual; day-to-day radiation safety in units and establishments; and appropriate responses to radiation accidents and emergencies. In addition, students are briefed on a limited number of peripheral topics and participate in some site visits. Currently, two Courses are held annually, each with about twenty students. Most of the material is presented by ADO personnel with external contractor support. The three Courses held to date have proved sufficiently successful, both for the students and the ADO generally, to seek national accreditation through the Australian National Training Authority and, as a first step, competency standards have been identified

  15. SASSYS-1 balance-of-plant component models for an integrated plant response

    International Nuclear Information System (INIS)

    Ku, J.-Y.

    1989-01-01

    Models of power plant heat transfer components and rotating machinery have been added to the balance-of-plant model in the SASSYS-1 liquid metal reactor systems analysis code. This work is part of a continuing effort in plant network simulation based on the general mathematical models developed. The models described in this paper extend the scope of the balance-of-plant model to handle non-adiabatic conditions along flow paths. While the mass and momentum equations remain the same, the energy equation now contains a heat source term due to energy transfer across the flow boundary or to work done through a shaft. The heat source term is treated fully explicitly. In addition, the equation of state is rewritten in terms of the quality and separate parameters for each phase. The models are simple enough to run quickly, yet include sufficient detail of dominant plant component characteristics to provide accurate results. 5 refs., 16 figs., 2 tabs

  16. Plant Survival in a Changing Environment: The Role of Nitric Oxide in Plant Responses to Abiotic Stress

    Science.gov (United States)

    Simontacchi, Marcela; Galatro, Andrea; Ramos-Artuso, Facundo; Santa-María, Guillermo E.

    2015-01-01

    Nitric oxide in plants may originate endogenously or come from surrounding atmosphere and soil. Interestingly, this gaseous free radical is far from having a constant level and varies greatly among tissues depending on a given plant’s ontogeny and environmental fluctuations. Proper plant growth, vegetative development, and reproduction require the integration of plant hormonal activity with the antioxidant network, as well as the maintenance of concentration of reactive oxygen and nitrogen species within a narrow range. Plants are frequently faced with abiotic stress conditions such as low nutrient availability, salinity, drought, high ultraviolet (UV) radiation and extreme temperatures, which can influence developmental processes and lead to growth restriction making adaptive responses the plant’s priority. The ability of plants to respond and survive under environmental-stress conditions involves sensing and signaling events where nitric oxide becomes a critical component mediating hormonal actions, interacting with reactive oxygen species, and modulating gene expression and protein activity. This review focuses on the current knowledge of the role of nitric oxide in adaptive plant responses to some specific abiotic stress conditions, particularly low mineral nutrient supply, drought, salinity and high UV-B radiation. PMID:26617619

  17. Demand Response Integration Through Agent-Based Coordination of Consumers in Virtual Power Plants

    DEFF Research Database (Denmark)

    Clausen, Anders; Umair, Aisha; Ma, Zheng

    2016-01-01

    of industrial loads. Coordination happens in response to Demand Response events, while considering local objectives in the industrial domain. We illustrate the applicability of our approach on a Virtual Power Plant scenario with three simulated greenhouses. The results suggest that the proposed design is able...... Power Plant design that is able to balance the demand of energy-intensive, industrial loads with the supply situation in the electricity grid. The proposed Virtual Power Plant design uses a novel inter-agent, multi-objective, multi-issue negotiation mechanism, to coordinate the electricity demands...... to coordinate the electricity demands of industrial loads, in compliance with external Demand Response events....

  18. Drought-induced trans-generational tradeoff between stress tolerance and defence: consequences for range limits?

    Science.gov (United States)

    Alsdurf, Jacob D; Ripley, Tayler J; Matzner, Steven L; Siemens, David H

    2013-01-01

    Areas just across species range boundaries are often stressful, but even with ample genetic variation within and among range-margin populations, adaptation towards stress tolerance across range boundaries often does not occur. Adaptive trans-generational plasticity should allow organisms to circumvent these problems for temporary range expansion; however, range boundaries often persist. To investigate this dilemma, we drought stressed a parent generation of Boechera stricta (A.Gray) A. Löve & D. Löve, a perennial wild relative of Arabidopsis, representing genetic variation within and among several low-elevation range margin populations. Boechera stricta is restricted to higher, moister elevations in temperate regions where generalist herbivores are often less common. Previous reports indicate a negative genetic correlation (genetic tradeoff) between chemical defence allocation and abiotic stress tolerance that may prevent the simultaneous evolution of defence and drought tolerance that would be needed for range expansion. In growth chamber experiments, the genetic tradeoff became undetectable among offspring sib-families whose parents had been drought treated, suggesting that the stress-induced trans-generational plasticity may circumvent the genetic tradeoff and thus enable range expansion. However, the trans-generational effects also included a conflict between plastic responses (environmental tradeoff); offspring whose parents were drought treated were more drought tolerant, but had lower levels of glucosinolate toxins that function in defence against generalist herbivores. We suggest that either the genetic or environmental tradeoff between defence allocation and stress tolerance has the potential to contribute to range limit development in upland mustards.

  19. Dopamine is a key regulator in the signalling pathway underlying predator-induced defences in Daphnia

    Science.gov (United States)

    Weiss, Linda C.; Leese, Florian; Laforsch, Christian; Tollrian, Ralph

    2015-01-01

    The waterflea Daphnia is a model to investigate the genetic basis of phenotypic plasticity resulting from one differentially expressed genome. Daphnia develops adaptive phenotypes (e.g. morphological defences) thwarting predators, based on chemical predator cue perception. To understand the genomic basis of phenotypic plasticity, the description of the precedent cellular and neuronal mechanisms is fundamental. However, key regulators remain unknown. All neuronal and endocrine stimulants were able to modulate but not induce defences, indicating a pathway of interlinked steps. A candidate able to link neuronal with endocrine responses is the multi-functional amine dopamine. We here tested its involvement in trait formation in Daphnia pulex and Daphnia longicephala using an induction assay composed of predator cues combined with dopaminergic and cholinergic stimulants. The mere application of both stimulants was sufficient to induce morphological defences. We determined dopamine localization in cells found in close association with the defensive trait. These cells serve as centres controlling divergent morphologies. As a mitogen and sclerotization agent, we anticipate that dopamine is involved in proliferation and structural formation of morphological defences. Furthermore, dopamine pathways appear to be interconnected with endocrine pathways, and control juvenile hormone and ecdysone levels. In conclusion, dopamine is suggested as a key regulator of phenotypic plasticity. PMID:26423840

  20. Plant species responses to oil degradation and toxicity reduction in ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-01-05

    Jan 5, 2009 ... contaminated soil and sediment is an emerging techno- logy that promises effective and inexpensive clean up of certain hazardous wastes (Simeon 1993; Nwoko, 1995). Some of these processes occurs within the plants and involves the degradation or breakdown of organic and inorganic contaminants ...

  1. Unexpected plant odor responses in a moth pheromone system

    Directory of Open Access Journals (Sweden)

    Angéla eRouyar

    2015-05-01

    Full Text Available Male moths rely on olfactory cues to find females for reproduction. Males also use volatile plant compounds (VPCs to find food sources and might use host-plant odor cues to identify the habitat of calling females. Both the sex pheromone released by conspecific females and VPCs trigger well-described oriented flight behavior towards the odor source. Whereas detection and central processing of pheromones and VPCs have been thought for a long time to be highly separated from each other, recent studies have shown that interactions of both types of odors occur already early at the periphery of the olfactory pathway. Here we show that detection and early processing of VPCs and pheromone can overlap between the two sub-systems. Using complementary approaches, i.e. single-sensillum recording of olfactory receptor neurons, in vivo calcium imaging in the antennal lobe, intracellular recordings of neurons in the macroglomerular complex (MGC and flight tracking in a wind tunnel, we show that some plant odorants alone, such as heptanal, activate the pheromone-specific pathway in male Agrotis ipsilon at peripheral and central levels. To our knowledge, this is the first report of a plant odorant with no chemical similarity to the molecular structure of the pheromone, acting as a partial agonist of a moth sex pheromone.

  2. Woody plants in drylands: plastic responses to environmental stress

    NARCIS (Netherlands)

    Xu, L.

    2012-01-01

    Plants in drylands are exposed to a suite of stress factors. The most obvious stress factor is drought stress induced by a strongly negative balance between precipitation and potential evapotranspiration. Drylands are increasingly being used for grazing livestock and with increasing human

  3. A comparison of responses to the Fukushima Daiichi Nuclear Plant

    International Nuclear Information System (INIS)

    Oshima, Teruo

    2011-01-01

    Many Institutions abroad have expressed their views on the Fukushima Daiichi Nuclear Power Plant accident. When more emphasis on risk and precaution, they differ markedly from that in Japan. One of the main causes of the accident lies in disregard for prior warnings about possible tsunami risks. This paper will discuss lessons we can learn from the accident and future problems. (author)

  4. Physiological blockage in plants in response to postharvest stress ...

    African Journals Online (AJOL)

    Flowers have been designed primarily for cutting because of the diversity of shapes, colors and also durability. However, ornamental plants are used in floral arrangements in vases and have limited shelf-life. Thus, this study showed that one of the factors contributing to this limitation is the physiological blockage that occurs ...

  5. A review of major factors influencing plant responses to recreation impacts

    Science.gov (United States)

    Kuss, Fred R.

    1986-09-01

    This article reviews some of the more important factors found to influence the susceptibility of plants to trampling impacts associated with recreational use of natural areas. A three-way interaction mediates plant responses to impacts: plant x environment x stress level(s). Plant responses vary in part according to the genetic constitution of the plant, life and growth form, the adaptive flexibility of the plant, and anatomical differences inherent to growth habit and morphology. Other factors that influence plant sensitivities to impacts are the habitat environments in which plants grow, since a number of conditions such as moisture excesses or deficiencies, nitrogen or oxygen starvation, late frosts, etc., cause physiological injury and may increase plant sensitivity to impacts. Among the environmental factors that may increase or lessen plant sensitivities to impacts are soil moisture levels, canopy density, elevation, aspect, microclimate, soil drainage, texture, fertility and productivity. Seasonal influences also bear consideration since environmental changes and phonological and physiological events are mediated by time of year. Stresses are caused by both direct and indirect forms of impact and vary according to season of use, frequency and amount of use, and the type of activity. These interactions are further complicated by evidence that inter- and intraspecific competition, antagonism, and commensalism may influence differences in the sensitivity of plant communities to impacts.

  6. Ecosystem Responses To Plant Phenology Across Scales And Trophic Levels

    Science.gov (United States)

    Stoner, D.; Sexton, J. O.; Nagol, J. R.; Ironside, K.; Choate, D.; Longshore, K.; Edwards, T., Jr.

    2015-12-01

    Plant phenology in arid and semi-arid ecoregions is constrained by water availability and governs the life history characteristics of primary and secondary consumers. We related the behavior, demography, and distribution of mammalian herbivores and their principal predator to remotely sensed vegetation and climatological indices across the western United States for the period 2000-2014. Across scales, terrain and topographic position moderates the effects of climatological drought on primary productivity, resulting in differential susceptibility among plant functional types to water stress. At broad scales, herbivores tie parturition to moist sites during the period of maximum increase in local forage production. Consequently, juvenile mortality is highest in regions of extreme phenological variability. Although decoupled from primary production by one or more trophic levels, carnivore home range size and density is negatively correlated to plant productivity and growing season length. At the finest scales, predation influences the behavior of herbivore prey through compromised habitat selection, in which maternal females trade nutritional benefits of high plant biomass for reduced mortality risk associated with increased visibility. Climate projections for the western United States predict warming combined with shifts in the timing and form of precipitation. Our analyses suggest that these changes will propagate through trophic levels as increased phenological variability and shifts in plant distributions, larger consumer home ranges, altered migration behavior, and generally higher volatility in wildlife populations. Combined with expansion and intensification of human land use across the region, these changes will likely have economic implications stemming from increased human-wildlife conflict (e.g., crop damage, vehicle collisions) and changes in wildlife-related tourism.

  7. Trichoderma-Plant Root Colonization: Escaping Early Plant Defense Responses and Activation of the Antioxidant Machinery for Saline Stress Tolerance

    Science.gov (United States)

    Brotman, Yariv; Landau, Udi; Cuadros-Inostroza, Álvaro; Takayuki, Tohge; Fernie, Alisdair R.; Chet, Ilan; Viterbo, Ada; Willmitzer, Lothar

    2013-01-01

    Trichoderma spp. are versatile opportunistic plant symbionts which can colonize the apoplast of plant roots. Microarrays analysis of Arabidopsis thaliana roots inoculated with Trichoderma asperelloides T203, coupled with qPCR analysis of 137 stress responsive genes and transcription factors, revealed wide gene transcript reprogramming, proceeded by a transient repression of the plant immune responses supposedly to allow root colonization. Enhancement in the expression of WRKY18 and WRKY40, which stimulate JA-signaling via suppression of JAZ repressors and negatively regulate the expression of the defense genes FMO1, PAD3 and CYP71A13, was detected in Arabidopsis roots upon Trichoderma colonization. Reduced root colonization was observed in the wrky18/wrky40 double mutant line, while partial phenotypic complementation was achieved by over-expressing WRKY40 in the wrky18 wrky40 background. On the other hand increased colonization rate was found in roots of the FMO1 knockout mutant. Trichoderma spp. stimulate plant growth and resistance to a wide range of adverse environmental conditions. Arabidopsis and cucumber (Cucumis sativus L.) plants treated with Trichoderma prior to salt stress imposition show significantly improved seed germination. In addition, Trichoderma treatment affects the expression of several genes related to osmo-protection and general oxidative stress in roots of both plants. The MDAR gene coding for monodehydroascorbate reductase is significantly up-regulated and, accordingly, the pool of reduced ascorbic acid was found to be increased in Trichoderma treated plants. 1-Aminocyclopropane-1-carboxylate (ACC)-deaminase silenced Trichoderma mutants were less effective in providing tolerance to salt stress, suggesting that Trichoderma, similarly to ACC deaminase producing bacteria, can ameliorate plant growth under conditions of abiotic stress, by lowering ameliorating increases in ethylene levels as well as promoting an elevated antioxidative capacity

  8. Proteomic analysis of grapevine resistance induced by Trichoderma harzianum T39 reveals specific defence pathways activated against downy mildew

    Science.gov (United States)

    Perazzolli, Michele

    2012-01-01

    Downy mildew is caused by the oomycete Plasmopara viticola and is one of the most serious diseases of grapevine. The beneficial microorganism Trichoderma harzianum T39 (T39) has previously been shown to induce plant-mediated resistance and to reduce the severity of downy mildew in susceptible grapevines. In order to better understand the cellular processes associated with T39-induced resistance, the proteomic and histochemical changes activated by T39 in grapevine were investigated before and 1 day after P. viticola inoculation. A comprehensive proteomic analysis of T39-induced resistance in grapevine was performed using an eight-plex iTRAQ protocol, resulting in the identification and quantification of a total of 800 proteins. Most of the proteins directly affected by T39 were found to be involved in signal transduction, indicating activation of a complete microbial recognition machinery. Moreover, T39-induced resistance was associated with rapid accumulation of reactive oxygen species and callose at infection sites, as well as changes in abundance of proteins involved in response to stress and redox balance, indicating an active defence response to downy mildew. On the other hand, proteins affected by P. viticola in control plants mainly decreased in abundance, possibly reflecting the establishment of a compatible interaction. Finally, the high-throughput iTRAQ protocol allowed de novo peptide sequencing, which will be used to improve annotation of the Vitis vinifera cv. Pinot Noir proteome. PMID:23105132

  9. Self-Defence as a Circumstance Precluding the Wrongfulness of the Use of Force

    Directory of Open Access Journals (Sweden)

    Cliff Farhang

    2015-07-01

    Full Text Available Roberto Ago, the International Law Commission’s second Special Rapporteur on the topic of state responsibility for internationally wrongful acts, defined self-defence as a faculté of a state to use force in response to an act of another state through which a breach of the principal obligation under Article 2(4 Charter is committed. On this basis, he then inserted a provision in Chapter V to Part One of the Draft Articles on State Responsibility expressing self-defence as a specific factual circumstance precluding the wrongfulness of the use of force which constitutes a response to state aggression. This conception of self-defence, although misunderstood from the onset, remained in the backdrop of the study of the law of state responsibility for a considerable period. It was only dismantled during the reign of the last Special Rapporteur on the topic of state responsibility, James Crawford. The last Rapporteur, at the onset, submitted that it is not the function of the Draft Articles to specify the content of the primary rules, including that referred to in Article 51 Charter. He then redefined the function of the circumstance of self-defence as that of precluding the wrongfulness of non-performance of certain obligations other than the general prohibition insofar as such non-performance is connected with the exercise of the right under Article 51 Charter.This contribution first scrutinises this paradigmatic shift and finds it to be symptomatic of the conviction on the part of Crawford that the notion of self-defence could also encompass the use of force against speculative threats of state origin as well as actual threats that emanate from individuals or groups which are disconnected from the organisation of any state. It then uses this finding as a springboard towards the examination of the controversy surrounding the notion of self-defence under international law. In that connection, it first outlines the findings of the World Court on the

  10. Responses and damages during long-term continuous irradiation in plants

    International Nuclear Information System (INIS)

    Watanabe, Yoshito

    2011-01-01

    Effects of long-term continuous irradiation are relevant to studies in radiation ecotoxicology. To investigate plants biological responses to continuous irradiation, we performed metabolome and transcriptome analysis in a model plant, arabidopsis. Comprehensive analysis of primary metabolites using capillary electrophoresis mass spectrometry revealed extensive metabolic changes at early onset of growth inhibition in plants exposed to gamma rays at the dose rate of 20 Gy/day. The changes included elevated levels of B vitamins and second metabolites, commonly responsive to many abiotic and biotic stresses. Responses at early onset of growth inhibition were also observed in the transcriptome analysis using microarray, which showed up-regulation of 55 genes in plants exposed to gamma rays at 20 Gy/day. Although about a half of the up-regulated genes were also responsive just after acute irradiation, the other half was responsive only during long-term continuous irradiation. Database analyses showed that the specifically up-regulated genes to long-term continuous irradiation included genes relating to general stress responses and protein metabolism. The results of these analyses appear to reflect plants responses to progressive radiation damages, from radiation-specific responses, which repair primary DNA damage, to more general stress responses, which maintain homoeostasis against secondary damages. (author)

  11. The role of moulting in parasite defence.

    Science.gov (United States)

    Duneau, David; Ebert, Dieter

    2012-08-07

    Parasitic infections consist of a succession of steps during which hosts and parasites interact in specific manners. At each step, hosts can use diverse defence mechanisms to counteract the parasite's attempts to invade and exploit them. Of these steps, the penetration of parasites into the host is a key step for a successful infection and the epithelium is the first line of host defence. The shedding of this protective layer (moulting) is a crucial feature in the life cycle of several invertebrate and vertebrate taxa, and is generally considered to make hosts vulnerable to parasites and predators. Here, we used the crustacean Daphnia magna to test whether moulting influences the likelihood of infection by the castrating bacterium Pasteuria ramosa. This parasite is known to attach to the host cuticula before penetrating into its body. We found that the likelihood of successful parasite infection is greatly reduced if the host moults within 12 h after parasite exposure. Thus, moulting is beneficial for the host being exposed to this parasite. We further show that exposure to the parasite does not induce hosts to moult earlier. We discuss the implications of our findings for host and parasite evolution and epidemiology.

  12. Preconscious defence analysis, memory and structural change.

    Science.gov (United States)

    Ross, John Munder

    2003-02-01

    Beginning with the ways in which the use of the couch lends 'depth to the surface' (Erikson, 1954), I explore the topography of the inter- and intrasubjective psychoanalytic situation and process. I suggest that defences are not by definition unconscious but rather can be observed operating at conscious and preconscious levels, particularly under these conditions. A focus on preconscious disavowal provides a window on what has become unconscious repression. As a result of eliciting and then verbalising the operation of such defences with regard to anxieties in the here-and-now transference, declarative memories of increasingly specific childhood fantasies and events begin to hold sway over unmanageable procedural remnants from the analysand's past. With this may even come the possibility of neuronal regeneration, the more generalisable enhancement of declarative and symbolic functions and the sense of identity with which these are associated. Herein may lie one enduring therapeutic effect of the 'talking cure' - putting feelings into words - as one among a variety of psychotherapeutic modalities.

  13. A change in temperature modulates defence to yellow (stripe) rust in wheat line UC1041 independently of resistance gene Yr36.

    Science.gov (United States)

    Bryant, Ruth R M; McGrann, Graham R D; Mitchell, Alice R; Schoonbeek, Henk-Jan; Boyd, Lesley A; Uauy, Cristobal; Dorling, Steve; Ridout, Christopher J

    2014-01-08

    Rust diseases are of major importance in wheat production worldwide. With the constant evolution of new rust strains and their adaptation to higher temperatures, consistent and durable disease resistance is a key challenge. Environmental conditions affect resistance gene performance, but the basis for this is poorly understood. Here we show that a change in day temperature affects wheat resistance to Puccinia striiformis f. sp tritici (Pst), the causal agent of yellow (or stripe) rust. Using adult plants of near-isogenic lines UC1041 +/- Yr36, there was no significant difference between Pst percentage uredia coverage in plants grown at day temperatures of 18°C or 25°C in adult UC1041 + Yr36 plants. However, when plants were transferred to the lower day temperature at the time of Pst inoculation, infection increased up to two fold. Interestingly, this response was independent of Yr36, which has previously been reported as a temperature-responsive resistance gene as Pst development in adult UC1041 -Yr36 plants was similarly affected by the plants experiencing a temperature reduction. In addition, UC1041 -Yr36 plants grown at the lower temperature then transferred to the higher temperature were effectively resistant and a temperature change in either direction was shown to affect Pst development up to 8 days prior to inoculation. Results for seedlings were similar, but more variable compared to adult plants. Enhanced resistance to Pst was observed in seedlings of UC1041 and the cultivar Shamrock when transferred to the higher temperature. Resistance was not affected in seedlings of cultivar Solstice by a temperature change in either direction. Yr36 is effective at 18°C, refining the lower range of temperature at which resistance against Pst is conferred compared to previous studies. Results reveal previously uncharacterised defence temperature sensitivity in the UC1041 background which is caused by a change in temperature and independently of Yr36. This novel

  14. Re-interpreting plant morphological responses to UV-B radiation

    Czech Academy of Sciences Publication Activity Database

    Matthew Robson, T.; Klem, Karel; Urban, Otmar; Jansen, M. A.

    2015-01-01

    Roč. 38, č. 5 (2015), s. 856-866 ISSN 0140-7791 R&D Projects: GA MŠk LD12030 Institutional support: RVO:67179843 Keywords : auxin homeostasis * canopy structure and light interception * chronic * acute stress * flavonoid accumulation * plant-plant interactions * stress-induced morphogenic responses (SIMR) * ultraviolet radiation * UVR8 photoreceptor * whole-plant phenotype Subject RIV: EH - Ecology, Behaviour Impact factor: 6.169, year: 2015

  15. BRIC-17 Mapping Spaceflight-Induced Hypoxic Signaling and Response in Plants

    Science.gov (United States)

    Gilroy, Simon; Choi, Won-Gyu; Swanson, Sarah

    2012-01-01

    Goals of this work are: (1) Define global changes in gene expression patterns in Arabidopsis plants grown in microgravity using whole genome microarrays (2) Compare to mutants resistant to low oxygen challenge using whole genome microarrays Also measuring root and shoot size Outcomes from this research are: (1) Provide fundamental information on plant responses to the stresses inherent in spaceflight (2) Potential for informing on genetic strategies to engineer plants for optimal growth in space

  16. Regulating the ethylene response of a plant by modulation of F-box proteins

    Science.gov (United States)

    Guo, Hongwei [Beijing, CN; Ecker, Joseph R [Carlsbad, CA

    2014-01-07

    The relationship between F-box proteins and proteins invovled in the ethylene response in plants is described. In particular, F-box proteins may bind to proteins involved in the ethylene response and target them for degradation by the ubiquitin/proteasome pathway. The transcription factor EIN3 is a key transcription factor mediating ethylne-regulated gene expression and morphological responses. EIN3 is degraded through a ubiquitin/proteasome pathway mediated by F-box proteins EBF1 and EBF2. The link between F-box proteins and the ethylene response is a key step in modulating or regulating the response of a plant to ethylene. Described herein are transgenic plants having an altered sensitivity to ethylene, and methods for making transgenic plant haing an althered sensitivity to ethylene by modulating the level of activity of F-box proteins. Methods of altering the ethylene response in a plant by modulating the activity or expression of an F-box protein are described. Also described are methods of identifying compounds that modulate the ethylene response in plants by modulating the level of F-box protein expression or activity.

  17. Diving bradycardia: a mechanism of defence against hypoxic damage.

    Science.gov (United States)

    Alboni, Paolo; Alboni, Marco; Gianfranchi, Lorella

    2011-06-01

    A feature of all air-breathing vertebrates, diving bradycardia is triggered by apnoea and accentuated by immersion of the face or whole body in cold water. Very little is known about the afferents of diving bradycardia, whereas the efferent part of the reflex circuit is constituted by the cardiac vagal fibres. Diving bradycardia is associated with vasoconstriction of selected vascular beds and a reduction in cardiac output. The diving response appears to be more pronounced in mammals than in birds. In humans, the bradycardic response to diving varies greatly from person to person; the reduction in heart rate generally ranges from 15 to 40%, but a small proportion of healthy individuals can develop bradycardia below 20 beats/min. During prolonged dives, bradycardia becomes more pronounced because of activation of the peripheral chemoreceptors by a reduction in the arterial partial pressure of oxygen (O2), responsible for slowing of heart rate. The vasoconstriction is associated with a redistribution of the blood flow, which saves O2 for the O2-sensitive organs, such as the heart and brain. The results of several investigations carried out both in animals and in humans show that the diving response has an O2-conserving effect, both during exercise and at rest, thus lengthening the time to the onset of serious hypoxic damage. The diving response can therefore be regarded as an important defence mechanism for the organism.

  18. NRC wants plant-specific responses on Thermo-Lag

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    Dissatisfied with recent industry-backed efforts to assure fire safety at nuclear power plants, the Nuclear Regulatory Commission announced on November 24 that it would direct all nuclear plant owners to specify the actions they would take to assure that the use of the Thermo-Lag 330 fire barrier material would not lead to insufficient protection of electrical cables connected to safe-shutdown systems. Previously, the NRC had been content to let the matter wait until tests sponsored by the Nuclear Management and Resources Council (Numarc) could show whether Thermo-Lag, used and installed in certain ways, would provide sufficient protection, but the NRC and Numarc have disagreed over the test methodology, and the Numarc tests are now considered to be several months behind schedule

  19. Yield components and quality of intercropped cotton in response to mepiquat chloride and plant density

    NARCIS (Netherlands)

    Mao, Lili; Zhang, Lizhen; Evers, J.B.; Werf, van der Wopke; Liu, Shaodong; Zhang, Siping; Wang, Baomin; Li, Zhaohu

    2015-01-01

    Cotton yield is greatly improved by moderately increasing plant density and modifying the cotton plants to have a compact structure, which is also required by the increasing demand for mechanized harvest. However, in cotton strip intercropped with wheat, only limited knowledge on yield response

  20. Taking mycocentrism seriously: mycorrhizal fungal and plant responses to elevated CO2

    NARCIS (Netherlands)

    Alberton, O.; Kuyper, T.W.; Gorissen, A.

    2005-01-01

    The aim here was to separately assess mycorrhizal fungal and plant responses under elevated atmospheric CO2, and to test a mycocentric model that assumes that increased carbon availability to the fungus will not automatically feed back to enhanced plant growth performance. Meta-analyses were applied

  1. Physiological and gene expression responses of sunflower (Helianthus annuus L.) plants differ according to irrigation placement.

    Science.gov (United States)

    Aguado, Ana; Capote, Nieves; Romero, Fernando; Dodd, Ian C; Colmenero-Flores, José M

    2014-10-01

    To investigate effects of soil moisture heterogeneity on plant physiology and gene expression in roots and leaves, three treatments were implemented in sunflower plants growing with roots split between two compartments: a control (C) treatment supplying 100% of plant evapotranspiration, and two treatments receiving 50% of plant evapotranspiration, either evenly distributed to both compartments (deficit irrigation - DI) or unevenly distributed to ensure distinct wet and dry compartments (partial rootzone drying - PRD). Plants receiving the same amount of water responded differently under the two irrigation systems. After 3 days, evapotranspiration was similar in C and DI, but 20% less in PRD, concomitant with decreased leaf water potential (Ψleaf) and increased leaf xylem ABA concentration. Six water-stress responsive genes were highly induced in roots growing in the drying soil compartment of PRD plants, and their expression was best correlated with local soil water content. On the other hand, foliar gene expression differed significantly from that of the root and correlated better with xylem ABA concentration and Ψleaf. While the PRD irrigation strategy triggered stronger physiological and molecular responses, suggesting a more intense and systemic stress reaction due to local dehydration of the dry compartment of PRD plants, the DI strategy resulted in similar water savings without strongly inducing these responses. Correlating physiological and molecular responses in PRD/DI plants may provide insights into the severity and location of water deficits and may enable a better understanding of long-distance signalling mechanisms. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  2. Soil carbon dioxide (CO 2 ) efflux of two shrubs in response to plant ...

    African Journals Online (AJOL)

    Although plant density should affect soil carbon dioxide (CO2) efflux and carbon cycling in semi-arid regions, the effects of plant density on soil CO2 efflux are not well known. This study was performed to investigate the responses of soil CO2 efflux of two dominant shrubs (Caragana korshinkii and Salix psammophila) to ...

  3. Plant responses to simulated hurricane impacts in a subtropical wet forest, Puerto Rico

    Science.gov (United States)

    Aaron B. Shiels; Jess K. Zimmerman; Diana C. García-Montiel; Inge Jonckheere; Jennifer Holm; David Horton; Nicholas. Brokaw

    2010-01-01

    1. We simulated two key components of severe hurricane disturbance, canopy openness and detritus deposition, to determine the independent and interactive effects of these components on woody plant recruitment and forest structure. 2. We increased canopy openness by trimming branches and added or subtracted canopy detritus in a factorial design. Plant responses were...

  4. Plant Response to TSWV and Seed Accumulation of Resveratrol in Peanut

    Science.gov (United States)

    Biotic and abiotic stress may induce peanut plants to produce a high amount of resveratrol. The relationship of plant response to tomato spotted wilt virus (TSWV) and seed accumulation of resveratrol was investigated. Twenty peanut accessions and six wild relatives were selected from the US peanut g...

  5. Defence-in-depth and development of safety requirements for advanced nuclear reactors

    International Nuclear Information System (INIS)

    Carnino, A.; Gasparini, M.

    2002-01-01

    The paper addresses a general approach for the preparation of the design safety requirements using the IAEA Safety Objectives and the strategy of defence-in-depth. It proposes a general method (top-down approach) to prepare safety requirements for a given kind of reactor using the IAEA requirements for nuclear power plants as a starting point through a critical interpretation and application of the strategy of defence-in-depth. The IAEA has recently developed a general methodology for screening the defence-in-depth of nuclear power plants starting from the fundamental safety objectives as proposed in the IAEA Safety Fundamentals. This methodology may provide a useful tool for the preparation of safety requirements for the design and operation of any kind of reactor. Currently the IAEA is preparing the technical basis for the development of safety requirements for Modular High Temperature Gas Reactors, with the aim of showing the viability of the method. A draft TECDOC has been prepared and circulated among several experts for comments. This paper is largely based on the content of the draft TECDOC. (authors)

  6. Response of Onion ( Allium cepa L.) to Irrigation Intervals and Plant ...

    African Journals Online (AJOL)

    08 at the Teaching and Research Farm of the College of Agriculture, Zuru, Kebbi State, Nigeria. The objective was to investigate the response of onion to irrigation interval and plant population density. The treatments consisted of factorial ...

  7. Site-Specific Seismic Site Response Model for the Waste Treatment Plant, Hanford, Washington

    Energy Technology Data Exchange (ETDEWEB)

    Rohay, Alan C.; Reidel, Steve P.

    2005-02-24

    This interim report documents the collection of site-specific geologic and geophysical data characterizing the Waste Treatment Plant site and the modeling of the site-specific structure response to earthquake ground motions.

  8. Responsiveness of cold tolerant chickpea characteristics in fall and spring planting: II. yield and yield components

    Directory of Open Access Journals (Sweden)

    ahmad nezami

    2009-06-01

    Full Text Available Previous research in Mashhad collection chickpeas (MCC has shown that there are some cold tolerant genotypes for fall planting in the highlands. To obtain more detailed information about the reaction of these genotypes to fall and spring planting, the yield and yield component responses of 33 chickpea genotypes (32 cold tolerant genotypes and one susceptible genotypes to four planting dates (28 Sep., 16 Oct., 2 Nov., and 7 Mar. were evaluated in 2000-2001 growing season. The experiment was conducted at the experimental field of college of agriculture, Ferdowsi University of Mashhad as a split plot design with two replications. The planting dates were imposed as main plot and chickpea genotypes as subplot. Effects of planting date and genotype on percent of plant survival (PPS after winter, number. of pod per plant, 100 seed weight, yield and Harvest Index (HI were significant (p

  9. Phytophagous insect fauna tracks host plant responses to exotic grass invasion.

    Science.gov (United States)

    Almeida-Neto, Mário; Prado, Paulo I; Lewinsohn, Thomas M

    2011-04-01

    The high dependence of herbivorous insects on their host plants implies that plant invaders can affect these insects directly, by not providing a suitable habitat, or indirectly, by altering host plant availability. In this study, we sampled Asteraceae flower heads in cerrado remnants with varying levels of exotic grass invasion to evaluate whether invasive grasses have a direct effect on herbivore richness independent of the current disturbance level and host plant richness. By classifying herbivores according to the degree of host plant specialization, we also investigated whether invasive grasses reduce the uniqueness of the herbivorous assemblages. Herbivorous insect richness showed a unimodal relationship with invasive grass cover that was significantly explained only by way of the variation in host plant richness. The same result was found for polyphagous and oligophagous insects, but monophages showed a significant negative response to the intensity of the grass invasion that was independent of host plant richness. Our findings lend support to the hypothesis that the aggregate effect of invasive plants on herbivores tends to mirror the effects of invasive plants on host plants. In addition, exotic plants affect specialist insects differently from generalist insects; thus exotic plants affect not only the size but also the structural profile of herbivorous insect assemblages.

  10. Physiological Response of Plants Grown on Porous Ceramic Tubes

    Science.gov (United States)

    Tsao, David; Okos, Martin

    1997-01-01

    This research involves the manipulation of the root-zone water potential for the purposes of discriminating the rate limiting step in the inorganic nutrient uptake mechanism utilized by higher plants. This reaction sequence includes the pathways controlled by the root-zone conditions such as water tension and gradient concentrations. Furthermore, plant based control mechanisms dictated by various protein productions are differentiated as well. For the nutrients limited by the environmental availability, the kinetics were modeled using convection and diffusion equations. Alternatively, for the nutrients dependent upon enzyme manipulations, the uptakes are modeled using Michaelis-Menten kinetics. In order to differentiate between these various mechanistic steps, an experimental apparatus known as the Porous Ceramic Tube - Nutrient Delivery System (PCT-NDS) was used. Manipulation of the applied suction pressure circulating a nutrient solution through this system imposes a change in the matric component of the water potential. This compensates for the different osmotic components of water potential dictated by nutrient concentration. By maintaining this control over the root-zone conditions, the rate limiting steps in the uptake of the essential nutrients into tomato plants (Lycopersicon esculentum cv. Cherry Elite) were differentiated. Results showed that the uptake of some nutrients were mass transfer limited while others were limited by the enzyme kinetics. Each of these were adequately modeled with calculations and discussions of the parameter estimations provided.

  11. Pareto Efficient Solution of Attack-Defence Trees

    NARCIS (Netherlands)

    Aslanyan, Zaruhi; Nielson, Flemming

    Attack-defence trees are a promising approach for representing threat scenarios and possible countermeasures in a concise and intuitive manner. An attack-defence tree describes the interaction between an attacker and a defender, and is evaluated by assigning parameters to the nodes, such as

  12. Computed Tomography Technology: Development and Applications for Defence

    International Nuclear Information System (INIS)

    Baheti, G. L.; Saxena, Nisheet; Tripathi, D. K.; Songara, K. C.; Meghwal, L. R.; Meena, V. L.

    2008-01-01

    Computed Tomography(CT) has revolutionized the field of Non-Destructive Testing and Evaluation (NDT and E). Tomography for industrial applications warrants design and development of customized solutions catering to specific visualization requirements. Present paper highlights Tomography Technology Solutions implemented at Defence Laboratory, Jodhpur (DLJ). Details on the technological developments carried out and their utilization for various Defence applications has been covered.

  13. Fallout: the defence, industrial and technological benefits of nuclear deterrence

    International Nuclear Information System (INIS)

    Tertrais, Bruno

    2015-01-01

    In the current climate of budgetary restrictions, it is fair to question the weight of military nuclear defence spending. Upon examination, however, nuclear deterrence has numerous military, industrial, and technological benefits. It is, in fact, totally intertwined with the other elements of our defence system. (author)

  14. Methodology to detect gaps in a soccer defence

    DEFF Research Database (Denmark)

    Knudsen, Nikolas Sten; Andersen, Thomas Bull

    2015-01-01

    The purpose of the present study was to create a methodology which can provide information about gaps in an opposing team’s defence. To illustrate the methodology, a defence was tracked during a game in the danish Superliga using ZXY radio tracking and analysed using the methodology. Results show...

  15. Considerations on Defence Thinking in Post-1994 South Africa with ...

    African Journals Online (AJOL)

    ... analyse and discuss the new comprehensive guidelines for defence force design in the Draft Defence Review 2012 and reflects on some of the most important policy implications for the SANDF in this regard – specifically given the demands placed on the SANDF in the field of post-conflict reconstruction and development.

  16. Quantitative Verification and Synthesis of Attack-Defence Scenarios Conference

    NARCIS (Netherlands)

    Aslanyan, Zaruhi; Nielson, Flemming; Parker, David

    Attack-defence trees are a powerful technique for formally evaluating attack-defence scenarios. They represent in an intuitive, graphical way the interaction between an attacker and a defender who compete in order to achieve conflicting objectives. We propose a novel framework for the formal

  17. Optimal plant water use across temporal scales: bridging eco-hydrological theories and plant eco-physiological responses

    Science.gov (United States)

    Manzoni, S.; Vico, G.; Palmroth, S.; Katul, G. G.; Porporato, A. M.

    2013-12-01

    unpredictable rainfall conditions, plant hydraulic traits (xylem and stomatal response to water availability) and morphological features (leaf and sapwood areas) must be coordinated - thus providing an ecohydrological interpretation of observed coordination (or homeostasis) among hydraulic traits. Moreover, the combinations of hydraulic traits and responses to drought that are optimal are found to depend on both total rainfall and its distribution during the growing season. Both drier conditions and more intense rainfall events interspaced by longer dry periods favor plants with high resistance to cavitation and delayed stomatal closure as soils dry. In contrast, plants in mesic conditions benefit from cavitation prevention through earlier stomatal closure. The proposed ecohydrological optimality criteria can be used as analytical tools to interpret variability in plant water use and predict trends in plant productivity and species composition under future climates.

  18. Response of plants to high concentrations of uranium stress and the screening of remediation plants

    International Nuclear Information System (INIS)

    Tang Yongjin; Luo Xuegang; Zeng Feng; Jiang Shijie

    2013-01-01

    Studies of the resistance and accumulation ability of different plant species to uranium (U) has important influence on the bioremediation of U contaminated soil. The resistance and enrichment ability of high concentrations of U (500 mg · kg"-"1 soil) in fourteen plant species were investigated and evaluated in this study in order to screen remediation plants for governance soil U contamination. The results showed that: (1) high concentrations of U stress had different effects on the emergence and survival of the different plants. The seed emergence of Hibiscus esculentus was reduced by 2/3, but the seed emergence of Gynura cusimbua (D. Don) S. Moore, Chenopodium album L. and Phaseolus vulgaris var. humilis Alef were not reduced. Under the contaminated soil, all the sesamum indicum died within a month after the emergence and the survival number of Amaranth and Iresine herbstii 'Aureo-reticulata' reduced by about 80%. But the survival number of Alternanthera philoxeroides (Mart.) Griseb., Chenopodium album L. and Phaseolus vulgaris var. humilis Alef were not influenced. (2) The biomass of the plants would be reduced by 8-99% in the uranium-contaminated soil. The anti-stress ability of Phaseolus vulgaris var. humilis Alef was the strongest in the fourteen plants, and Cucurbita pepo L., Sorghumbicolor (L.) Moench, Ipomoea aquatica Forsk, Helianthus annuus, Chenopodium album L. and Alternanthera philoxeroides (Mart.) Griseb. showed some the anti-stress ability. (3) Significant differences were found in the capacity of plants to absorb uranium between under high-uranium contaminated soil and under the non-uranium contaminated soil were. The plants with higher uranium content in thenon-contaminated soil were Gomphrena globosa, and Cucurbita pepo L., which were 2.249 mg · kg"-"1 DW and 1.620 mg · kg"-"1 DW, respectively. But the plants with higher uranium content in the high uranium contaminated soil were Cichorium intybus L., Amaranth and Ipomoea aquatica Forsk, which

  19. The Skeletal Muscle Anabolic Response to Plant- versus Animal-Based Protein Consumption.

    Science.gov (United States)

    van Vliet, Stephan; Burd, Nicholas A; van Loon, Luc J C

    2015-09-01

    Clinical and consumer market interest is increasingly directed toward the use of plant-based proteins as dietary components aimed at preserving or increasing skeletal muscle mass. However, recent evidence suggests that the ingestion of the plant-based proteins in soy and wheat results in a lower muscle protein synthetic response when compared with several animal-based proteins. The possible lower anabolic properties of plant-based protein sources may be attributed to the lower digestibility of plant-based sources, in addition to greater splanchnic extraction and subsequent urea synthesis of plant protein-derived amino acids compared with animal-based proteins. The latter may be related to the relative lack of specific essential amino acids in plant- as opposed to animal-based proteins. Furthermore, most plant proteins have a relatively low leucine content, which may further reduce their anabolic properties when compared with animal proteins. However, few studies have actually assessed the postprandial muscle protein synthetic response to the ingestion of plant proteins, with soy and wheat protein being the primary sources studied. Despite the proposed lower anabolic properties of plant vs. animal proteins, various strategies may be applied to augment the anabolic properties of plant proteins. These may include the following: 1) fortification of plant-based protein sources with the amino acids methionine, lysine, and/or leucine; 2) selective breeding of plant sources to improve amino acid profiles; 3) consumption of greater amounts of plant-based protein sources; or 4) ingesting multiple protein sources to provide a more balanced amino acid profile. However, the efficacy of such dietary strategies on postprandial muscle protein synthesis remains to be studied. Future research comparing the anabolic properties of a variety of plant-based proteins should define the preferred protein sources to be used in nutritional interventions to support skeletal muscle mass gain

  20. Transcription Factor Functional Protein-Protein Interactions in Plant Defense Responses

    Directory of Open Access Journals (Sweden)

    Murilo S. Alves

    2014-03-01

    Full Text Available Responses to biotic stress in plants lead to dramatic reprogramming of gene expression, favoring stress responses at the expense of normal cellular functions. Transcription factors are master regulators of gene expression at the transcriptional level, and controlling the activity of these factors alters the transcriptome of the plant, leading to metabolic and phenotypic changes in response to stress. The functional analysis of interactions between transcription factors and other proteins is very important for elucidating the role of these transcriptional regulators in different signaling cascades. In this review, we present an overview of protein-protein interactions for the six major families of transcription factors involved in plant defense: basic leucine zipper containing domain proteins (bZIP, amino-acid sequence WRKYGQK (WRKY, myelocytomatosis related proteins (MYC, myeloblastosis related proteins (MYB, APETALA2/ ETHYLENE-RESPONSIVE ELEMENT BINDING FACTORS (AP2/EREBP and no apical meristem (NAM, Arabidopsis transcription activation factor (ATAF, and cup-shaped cotyledon (CUC (NAC. We describe the interaction partners of these transcription factors as molecular responses during pathogen attack and the key components of signal transduction pathways that take place during plant defense responses. These interactions determine the activation or repression of response pathways and are crucial to understanding the regulatory networks that modulate plant defense responses.