Stilbene compounds and stilbene synthase expression during ripening, wilting, and UV treatment in grape cv. Corvina

The content of selected phenolic compounds including resveratrol (trans-3,5 ,4'-trihydroxystilbene) and its cis-isomer and glucosides (piceides) were m onitored in grape (Vitis vinifera L. cv. Corvina) berry skin during ripenin g in the vineyard and in response to the post-harvest drying process (wilti ng). Four wilting conditions were compared (traditional, mixed, low-tempera ture., and high-temperature) to verify the eliciting effect of drying on re sveratrol production. During fruit ripening the cis-piceid was the major st ilbene found in berry skins, and a weak accumulation of stilbene synthase ( STS) mRNA was observed, whereas UV-light irradiation greatly stimulated STS transcript of unripe berries. A time-course experiment showed the highest STS mRNA accumulation and resveratrol content (34 mug/g fresh weight at 58 days) occurring in berry skins in a mixed wilting process.