PlantDefenses213-page8

PlantDefenses213-page8 - fungal pathogens. One PR protein...

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Plant Stress and Defense Mechanisms - 8 When the plant receptor protein and the pathogen receptor protein match, the plant mounts defenses against invasion by the pathogen. The Hypersensitive Response The usual response mechanism with an Avr-R interaction is to produce antimicrobial agents, called phytoalexins, and PR proteins (pathogenesis- related proteins) in the infected tissues, a response known as the hypersensitive response (HR). One phytoalexin, camalexin, produced by Arabidopsis , is synthesized from the amino acid, tryptophan. The PR proteins include enzymes that degrade the cell walls of bacterial and
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Unformatted text preview: fungal pathogens. One PR protein is chitinase, which degrades the chitin walls of fungi. PR proteins also serve as warning molecules within the plant. PR protein response is less rapid than some other plant defenses. • Hydrogen peroxide and nitric acid are often synthesized immediately in the wound area that trigger events leading to cell death of the affected plant cells. These chemicals are often toxic to the pathogen as well. • When a gene specific defense is successful, the plant typically seals off the infected area forming a necrosis, destroying both its own tissue and the pathogen....
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This note was uploaded on 01/08/2012 for the course BIO 213 taught by Professor Makina during the Fall '09 term at SUNY Stony Brook.

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