Ultraviolet-B Radiation and Water Deficit Interact to Alter Flavonol and Anthocyanin Profiles in Grapevine Berries through Transcriptomic Regulation

UV-B radiation and water deficit may trigger flavonol and anthocyanin biosynthesis in plant tissues. In addition, previ-ous research has showed strong qualitative effects on grape berry skin flavonol and anthocyanin profiles in response to UV-B and water deficit. The aim of this study is to identify the mechanisms leading to quantitative and qualitative changes in flavonol and anthocyanin profiles, in response to separate and combined UV-B and water deficit. Grapevines (Vitis vinifera L. cv. Tempranillo) were exposed to three levels of UV-B radiation (0, 5.98 and 9.66 kJm2 day1) and subjected to two water regimes. A strong effect of UV-B on flavonol and anthocyanin biosyn-thesis was found, resulting in an increased anthocyanin con-centration and a change in their profile. Concomitantly, two key biosynthetic genes (FLS1 and UFGT) were up-regulate