Anthocyanin accumulation and biosynthesis are modulated by regulated deficit irrigation in Cabernet Sauvignon (Vitis Vinifera L.) grapes and wines

Anthocyanins contents and compositions play an important role in grape berries and wines. Grapevines are widely cultivated in arid and semi-arid areas, and water shortage restricts the development of wine industry. The aim of this work was to gain insight on the effect of regulated deficit irrigation (RDI) on the accumulation and biosynthesis of anthocyanins in Cabernet Sauvignon (Vitis Vinifera L.) grapes and wines. High-performance liquid chromatography (HPLC) was used for anthocyanins profiles analyses and real-time quantitative PCR (qRT-PCR) was used for the genes expressions measurement. The grapevines were treated with 60% (RDI-1), 70% (RDI-2), 80% (RDI-3), 100% (CK, traditional drip irrigation) of their estimated evapotranspiration (ETc) respectively. RDI treatments significantly reduced titration acid and increased pH with higher total soluble solids. RDI-1 treatment increased total anthocyanins contents in berries and wines in both two vintages. RDI-1 and RDI-2 treatments significantly increased the contents of acylated anthocyanins in berries and wines, especially Malvidin-3-acetly-glucoside. RDI treatments significantly increased non-acylated anthocyanins contents in wines, such as Delphinidin-3-gliucoside and Malvidin-3-glucoside. RDI treatments upregulated the expressions of VvPAL, VvC4H, VvCHS, VvF3'H, VvF3'5'H, VvLDOX, and VvOMT in both two vintages. Correlation analysis showed the accumulation of anthocyanins was closely related to the key genes expressions, including VvPAL, VvF3'H, VvF3'5'H etc. The present results provided direct evidence and detailed data to explain that RDI treatments regulated the accumulation of anthocyanins by regulating genes expressions in the anthocyanin synthesis pathway.