Mode of action of fungal elicitors

Department of Biochemistry, Faculty of Science, Masaryk University, Brno, CZ Plant resistance includes the activation of diverse defense mechanisms. The response involves opening of numerous ion channels, posttranslation modification of proteins by protein kinases, activation of the enzymes of the synthesis of active oxygen species, synthesis low molecular defense substances called phytoalexines and transcriptional activation of numerous defense-related genes. Moreover, several signaling molecules are generated to ensure coordination of defense response. Elicitors are monomeric, oligomeric and polymeric substances able to trigger the defense reaction cascade after the interaction with a plant receptor. As for their structure, they comprise the group of oligosaccharides, oligogalacturonides, oligochitosacharides (from fungal or plant cell walls), some specific proteins produced by pathogens and low molecular substances as ergosterol or other lipids. The most frequent defense and signaling mechanism are described below: 1) Hypersensitive reaction as a result of localized cell death 2) Reactive oxygen species are often produced during the early stage of plant resistance response 3) Production of nitric oxide induced during incompatible interactions in plants 4) Cell wall fortification with the deposition of callose, lignin, hydroxyproline-rich proteins 5) Synthesis of salicylic acid and jasmonic acid necessary for the induction of some plant defense genes 6) Induction of so called pathogenesis-related proteins (PR proteins) 7) Synthesis of organic and inorganic secondary metabolites - phytoalexins 8) Induction of localized or systemic plant resistance (usually non specific) against pathogens "Source":[ http://www.sci.muni.cz/~mikes/fungi.html#Laboratory%20of%20plant-pathogen%20interactions]

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