Grape variety related trans-resveratrol induction affects Aspergillus carbonarius growth and ochratoxin A biosynthesis

The paper reports the results of a study performed to investigate the influence of the grape variety on the growth of Aspergillus carbonarius on grape berries and the correlation between the amount of ochratoxin A (OTA) and the content of trans-resveratrol produced after fungal contamination. Variations in the amount of OTA produced by the fungus are observed depending on both grape variety and on the induction of trans-resveratrol determined during the infection. The obtained data suggest that if an increase in transresveratrol production in grape berries occurs early after the fungal infection, the berry exploits this compound to control OTA synthesis. If the increase in trans-resveratrol concentration is delayed after fungal infection (40 h), a control of OTA accumulation can not be achieved. The possibility of exerting significant control of OTA biosynthesis by this phytoalexin seems to rely in the promptness of its production, as occurs also in other fungus plant interactions and, in turn, seems to be dependent also on grape cultivar. In this fungus-plant system, trans-resveratrol appears to represent a defence-related compound toward A. carbonarius and OTA contamination.