Stilbene oligomer phytoalexins in grape as a response to Aspergillus carbonarius infection

Stilbenes are grapevine phytoalexins elicited by biotic and abiotic agents; Aspergillus carbonarius is a widespread ochratoxin A producing fungus present in warm conditions, such as in Southern Italy. To increase the knowledge on biosynthesis of stilbene oligomers induced by A. carbonarius infection, grape berries of the Southern Italian grape cv. Negro Amaro were inoculated. Significant increase of transresveratrol and resveratrol dimers and oligomers, such as caraphenol, E-ε-viniferin, u-viniferin, d-viniferin, a-viniferin, E-miyabenol C, and two tetramers, was observed, and concomitant decrease of glycoside derivatives. These findings improve the knowledge on the phytoalexin production as response against this pathogen.