Correction to Mass Spectrometric and Enzymatic Evidence Confirm the Existence of Anthocyanidin 3,5-O-Diglucosides in Cabernet Sauvignon (Vitis vinifera L.) Grape Berries

It has been widely accepted that anthocyanidin 3,5-O-diglucosides do not exist in Vitis vinifera L. Cabernet Sauvignon (CS) berries. However, our anthocyanin analyses using HPLC–ESI-MS/MS detected the existence of a low level of anthocyanidin 3,5-O-diglucosides in the Cabernet Sauvignon grape berries grown in China. The authenticity of these samples was confirmed with microsatellite markers. The existence of anthocyanidin 3,5-O-diglucoside was further verified by the enzymatic evidence for the first time. Four putative 5-O-glucosyltransferase (5GT) genes were isolated from the Cabernet Sauvignon berries. The enzymatic analysis showed that a recombinant protein (designated as Vv5GT3) glucosylated the 3-O- and 5-O-positions of anthocyanidins and flavonols. A phylogenetic analysis revealed that this bifunctional enzyme belongs to the 5GT subfamily of UDP-glycosyltransferases. This finding brought a new understanding of the anthocyanins’ profile and their biosynthesis in V. vinifera and would be helpful for f...