Journal of Plant Diseases and Protection (2007) 114, 9-13

M.J. Stadnik and W. Bettiol (2007)
Association between lipoxygenase and peroxidase activity and systemic protection of cucumber plants against Podosphaera xanthii induced by Oudemansiella canarii extracts
Journal of Plant Diseases and Protection 114 (1), 9-13
Abstract: This study was done to determine the relationship between the changes in lipoxygenase (LOX) and peroxidase (POX) activity and the protection of cucumber (Cucumis sativus) against powdery mildew (Podosphaera xanthii) induced by hexane or ethyl acetate extracts of basidiocarps of Oudemansiella canarii. At the two-leaf stage, only the primary leaves of the greenhouse grown cucumber plants were sprayed with either extract. The secondary leaves were inoculated at 1, 4, 7 or 10 days after the spray and the number of powdery mildew colonies were counted after 6 days. The LOX and POX activity in secondary leaves was determined 24 h after inoculation. In vitro antimicrobial effect of the extracts was tested against Bacillus and Cladosporium. Maximum disease reduction (85%) occurred when plants were inoculated one day after applying hexane extract. The disease reduction then decreased abruptly to 30% on the 4^th day, but then increased again when plants were inoculated seven or ten days after treatment. LOX activity increased only by the hexane extract application, but not by the pathogen. POX activity was higher in inoculated plants previously treated with the hexane extract. On the other hand, ethyl acetate extract did not affect the enzyme activity and its protection efficacy decreased continuously with increasing time interval between treatment and inoculation. Although both extracts showed antimicrobial activity in vitro, the results suggest that apolar compound(s) from the basidiocarps of O. canarii also induce systemic resistance to powdery mildew.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Marciel J. Stadnik, Wagner Bettiol

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

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Podosphaera xanthii	Cucumber (Cucumis sativus)