Figure 1.

Anthocyanin biosynthesis pathway and the regulation factors. (A) Schematic pathway of anthocyanin biosynthesis in plants and the chemical structure of anthocyanins. Blue and light-red boxes represent EBGs and LBGs. (B) Other factors regulate anthocyanin accumulation in plants through affecting the MBW complex. The key LBGs DFR, ANS and UFGT are mainly regulated by a conserved MYB-bHLH-WDR (MBW) complex. The MBW complex interacts with other transcriptional factors and is regulated by phytohormones including ethylene, ABA (abscisic acid) and JA (jasmonic acid). The environment factors temperature and light signal affect the activity of the MBW complex. PAL, phenylalanine ammonia lyase; C4H, cinnamate 4-hydroxylase; 4CL, cinnamic acid-4-hydroxylase; CHS, Chalcone synthase; CHI, chalcone isomerase; F3H, flavanone-3-hydroxylase; F3′H, flavanone 3′-hydroxylase; F3′5′H, flavanone 3′5′-hydroxylase; DFR, dihydroflavonol 4-reductase; ANS, anthocyanidin synthetase; UFGT, flavonoid 3-O-glucosyltransferase.