Characterization of a pterostilbene dehydrodimer produced by laccase of Botrytis cinerea

In the interaction between grapevines and Botrytis cinerea, one of the main aspects of pathogenicity is fungal ability to degrade phytoalexins synthes ized by the plant in response to infection. Laccase-like stilbene oxidase a ctivity in liquid cultures of B. cinerea has been shown to be related to th e decrease of phytoalexin concentrations. Recent research and results prese nted in this paper determined the chemical structure of a pterostilbene met abolite produced by B, cinerea. Study of degradation of pterostilbene that has just one free hydroxy phenyl group function allowed us to determine the oxidative dimerization process undergone by grapevine phytoalexins after B . cinerea infection. The phytopathological significance of this degradation process in the B, cinerea interaction has also been discussed.