Phytopathology (2006) 96, 1188-1194

Aziz Aziz, Patricia Trotel-Aziz, Laurent Dhuicq, Philippe Jeandet, Michel Couderchet and Guy Vernet (2006)
Chitosan oligomers and copper sulfate induce grapevine defense reactions and resistance to gray mold and downy mildew
Phytopathology 96 (11), 1188-1194
Abstract: Chitosan (CHN), a deacetylated derivative of chitin, was shown to be efficient in promoting plant defense reactions. CHN oligomers of different molecular weight (MW) and degree of acetylation (DA) triggered an accumulation of phytoalexins, trans- and cis-resveratrol and their derivatives epsilon-viniferin and piceid, in grapevine leaves. Highest phytoalexin production was achieved within 48 h of incubation with CHN at 200 µg/ml with an MW of 1,500 and a DA of 20% (CHN1.5/20), while oligomers with greater MW were less efficient, indicating that a specific MW threshold could be required for phytoalexin response. Treatment of grapevine leaves by highly active CHN1.5/20 also led to marked induction of chitinase and beta-1,3-glucanase activities. CHN1.5/20 applied together with copper sulfate (CuSO₄) strongly induced phytoalexin accumulation. CuS O₄ alone, especially at low concentrations also elicited a substantial production of phytoalexins in grapevine leaves. Evidence is also provided that CHN1.5/20 significantly reduced the infection of grapevine leaves by Botrytis cinerea and Plasmopara viticola, and in combination with CuSO₄ conferred protection against both pathogens.
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Database assignments for author(s): Aziz Aziz

Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host
control - general

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Plasmopara viticola	Grapevine (Vitis)
	Botrytis cinerea	Grapevine (Vitis)