Role of anthocyanidin reductase, encoded by BANYULS in plant flavonoid biosynthesis

Condensed tannins (CTs) are flavonoid oligomers, many of which have beneficial effects on animal and human health. The flavanol (-)-epicatechin is a component of many CTs and contributes to flavor and astringency in tea and wine. We show that the BANYULS ( BAN) genes from Arabidopsis thaliana and Medicago truncatula encode anthocyanidin reductase, which converts anthocyanidins to their corresponding 2,3-cis-avan-3-ols. Ectopic expression of BAN in tobacco flower petals and Arabidopsis leaves results in loss of anthocyanins and accumulation of CTs.