Effect of Flavin Inhibitors on Photoactivation of Oospores of Pbytopbtbora cactorum
Banihashemj. Z Mitchell. J . E
Journal of Phytopathology ; 1989 [Vol.126] Pages:167-174
Abstract
When dark-grown mature oospores of Phytophthora cactorum were activated to germinate bv exposure to 5 uW cm-2 nm-1 of fluorescent light ai 20—220C in the presence of certam flavm inhibitors such as KI, saiicylhydroxamie acid and phenylacetic acid ai 40, 1. and 0.1 mM respectivclv, photoactivation and hence subsequent germination of oospores were inhibited without appreciable irreversible effect on oospore viability. Likew-ise, when applied during the light period, NaN3, and KCN at I mM reduced photoactivation but had a minimal effect on dark reactions. Diphenylamine, an inhibitor ot certain carotcnoids, had no effect on photoactivation ot oospores. The data suggest that the photorecL-ptor pigment for activation of oospore germination is a flavin.
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