Fig. 1.

The Arabidopsis flavonoid pathway for the synthesis of anthocyanins and oxidized tannins, or proanthocyanidins (PAs). The large brackets indicate the late biosynthetic genes (LBGs) directly regulated by the MBW complex: on the left is the anthocyanin-specific MBW complex; on the right is the PA-specific MBW complex. The small bracket on the right indicates the narrow subset of LBGs encoding the transport steps regulated by TTG2. Dashed lines indicate multiple steps. Depicted on the left is a wild-type seedling expressing purplish red anthocyanins in the hypocotyl and parts of the cotyledons early in Arabidopsis development. Depicted on the right are Arabidopsis wild-type dry seed showing the brownish orange PA pigments expressed in the seed coat.