Search results for "defense"
showing 10 items of 247 documents
Root fungal endophytes: identity, phylogeny and roles in plant tolerance to metal stress.
2021
International audience; Metal trace elements accumulate in soils mainly because of anthropic activities, leading living organisms to develop strategies to handle metal toxicity. Plants often associate with root endophytic fungi, including nonmycorrhizal fungi, and some of these organisms are associated with metal tolerance. The lack of synthetic analyses of plant-endophyte-metal tripartite systems and the scant consideration for taxonomy led to this review aiming (1) to inventory non-mycorrhizal root fungal endophytes described with respect to their taxonomic diversity and (2) to determine the mutualistic roles of these plant-fungus associations under metal stress. More than 1500 species in…
Priming: getting ready for battle
2006
International audience; Infection of plants by necrotizing pathogens or colonization of plant roots with certain beneficial microbes causes the induction of a unique physiological state called “priming.” The primed state can also be induced by treatment of plants with various natural and synthetic compounds. Primed plants display either faster, stronger, or both activation of the various cellular defense responses that are induced following attack by either pathogens or insects or in response to abiotic stress. Although the phenomenon has been known for decades, most progress in our understanding of priming has been made over the past few years. Here, we summarize the current knowledge of p…
Integrated signaling network involving calcium, nitric oxide, active oxygen species but not mitogen-activated protein kinases in BcPG1-elicited grape…
2006
We have already reported the identification of the endopolygalacturonase 1 (BcPG1) from Botrytis cinerea as a potent elicitor of defense responses in grapevine, independently of its enzymatic activity. The aim of the present study is the analysis of the signaling pathways triggered by BcPG1 in grapevine cells. Our data indicate that BcPG1 induces a Ca2+ entry from the apoplasm, which triggers a phosphorylation-dependent nitric oxide (NO) production via an enzyme probably related to a NO synthase. Then NO is involved in i) cytosolic calcium homeostasis, by activating Ca2+ release from internal stores and regulating Ca2+ fluxes across the plasma membrane, ii) plasma membrane potential variat…
Survival cost of an early immune soliciting in nature.
2009
8 pages; International audience; If immune functions confer obvious benefits to hosts, life-history theory assumes that they also induce costs, leading to trade-offs between immunity and other fitness components. However, whether substantial fitness costs are associated with immune systems in the wild is debatable, as numerous factors may influence the costs and benefits associated with immune activation. Here, we explore the survival cost of immune deployment in postfledging birds. We injected Eurasian collared dove nestlings (Streptopelia decaocto) with antigens from Escherichia coli, and examined whether this immune challenge affected survival after fledging. To assess survival, birds we…
Regulation of plant NADPH oxidase.
2007
Addendum to: Regulation of Reactive Oxygen Species Production by a 14-3-3 Protein in Elicited Tobacco Cells. T. Elmayan, J. Fromentin, C. Riondet, G. Alcaraz, J. Blein and F. Simon-Plas. Plant Cell Environ 2007; 30:722–32; International audience; The production of Reactive Oxygen Species (ROS) is one of the key events occurring during the response of plants to environmental changes, and contributing to establish adaptive signaling pathways. A plasma membrane bound NADPH oxidase enzyme has been evidenced as the ROS producing system in various plant‑microorganisms interactions. We very recently reported, that a protein of the 14‑3‑3 family was able to interact directly with the C‑terminus par…
Image analysis methods for assessment of H2O2 production and Plasmopara viticola development in grapevine leaves: application to the evaluation of re…
2013
article i nfo The grapevine downy mildew (Plasmopara viticola) provokes severe damages and destroys the harvest in the absence of an effective protection. Numerous fungicide treatments are thus generally necessary. To promote a sustainable production, alternative strategies of protection including new antifungal molecules, resistant geno- types or elicitor-induced resistance are under trial. To evaluate the relevance of these strategies, resistance tests are required. In this context, three image analysis methods were developed to read the results of tests performed to assessP.viticolasporulation and mycelial development, and H 2 O 2 production in leaves. They have been validated using elic…
Effect of Juvenile Hormone on Resistance against Entomopathogenic Fungus Metharizium robertsii Differs between Sexes
2020
Juvenile hormone has been suggested to be a potential mediator in the trade-off between mating and insects&rsquo
Chemistry of defensive secretions in nymphs and adults of fire bug , Pyrrhocoris apterus L.(Heteroptera, Pyrrhocoridae)
1992
International audience; The defensive secretions from the nymphs and the adults of both sexes in P. apterus were chemically investigated. Forty components were identified from the nymphal posterior dorsoabdominal glands and 35 from the adult metathoracic glands of both sexes. Within the 43 identified chemicals, we found 23 aldehydes, five saturated hydrocarbons, five alcohols, three ketones, three lactones, two terpenes, one phenol and one ester. Thirteen of these compounds had never been reported within the Heteroptera. Whereas eight components are specific to the nymphs, methyl pentenal, (E)-2-hexenol, and heptadecanal are the only adult-specific components. The biological role of all the…
NADPH Oxidase-Mediated Reactive Oxygen Species Production: Subcellular Localization and Reassessment of Its Role in Plant Defense
2009
International audience; Chemiluminescence detection of reactive oxygen species (ROS) triggered in tobacco BY-2 cells by the fungal elicitor cryptogein was previously demonstrated to be abolished in cells transformed with an antisense construct of the plasma membrane NADPH oxidase, NtrbohD. Here, using electron microscopy, it has been confirmed that the first hydrogen peroxide production occurring a few minutes after challenge of tobacco cells with cryptogein is plasma membrane located and NtrbohD mediated. Furthermore, the presence of NtrbohD in detergent-resistant membrane fractions could be associated with the presence of NtrbohD-mediated hydrogen peroxide patches along the plasma membran…
Real-time electrochemical detection of extracellular nitric oxide in tobacco cells exposed to cryptogein, an elicitor of defence responses
2008
International audience; It was previously reported that cryptogein, an elicitor of defence responses, induces an intracellular production of nitric oxide (NO) in tobacco. Here, the possibility was explored that cryptogein might also trigger an increase of NO extracellular content through two distinct approaches, an indirect method using the NO probe 4,5-diaminofluorescein (DAF-2) and an electrochemical method involving a chemically modified microelectrode probing free NO in biological media. While the chemical nature of DAF-2-reactive compound(s) is still uncertain, the electrochemical modified microelectrodes provide real-time evidence that cryptogein induces an increase of extracellular N…