Anthocyanins and proanthocyanins are two classes of flavonoids with benefits for human health. The biosynthesis of anthocyanins and proanthocyanins shares a common up-stream biosynthetic pathway. The genes regulating their biosynthesis, namely the ternary MYB-bHLH-WD40 protein complexes, are conserved in higher plants. In Arabidopsis thaliana, AtTT19 is necessary for both anthocyanin and proanthocyanin accumulation. However, it remains unclear whether TT19-like glutathione S -transferase (GST) is recruited to participate in proanthocyanin accumulation in other plants.