Figure 1.

A schematic of the core anthocyanin biosynthetic pathway (ABP; rectangle) and its regulation (ellipse). The core enzymes of the ABP are listed as abbreviations above the arrows in boxes, while the products of each enzymatic reaction are listed next to the arrows. The hexagon labeled “MYB” can refer to either R2R3-MYB or R3-MYB proteins. The MBW complex is known to regulate the ABP, as well as several other aspects of epidermal cell differentiation (connected by arrows). The precise ABP targets of the MBW complex vary among species, so no connections are drawn. For simplicity, various ABP repressors are not shown. Additional non-anthocyaninic flavonoids produced as side branches of the core ABP are connected by arrows to the ABP. Abbreviations: CHS, chalcone synthase; CHI, chalcone isomerase; F3H, flavonoid 3-hydroxylase; F3′H, flavonoid 3′ hydroxylase; F3′5′H, flavonoid 3′ 5′ hydroxylase; DFR, dihydroflavonol 4-reductase; ANS, anthocyanidin synthase.