KENAF PHYTOALEXIN - TOXICITY OF O-HIBISCANONE AND ITS HYDROQUINONE TOTHE PLANT-PATHOGENS VERTICILLIUM-DAHLIAE AND FUSARIUM-OXYSPORUM F SP.VASINFECTUM

o-Hibiscanone (HBQ) is a phytoalexin produced by kenafin response to i nfection by the wilt pathogen Verticillium dahliae. In several bioassa ys utilizing both conidia and mycelia of V. dahliae, HBQ was significa ntly more toxic than desoxyhemigossypol, the most; potent phytoalexin produced by cotton. HBQ also was more toxic to conidia of Fusarium oxy sporum f, sp. vasinfectum. C-13-NMR experiments revealed that HBQ is r educed to its hydroquinone by V. dahliae conidia. Bioassays of HBQ and its hydroquinone established that the quinone is considerably more to xic to V. dahliae than is the hydroquinone. This biotransformation app arently represents a detoxification mechanism employed by the pathogen .