Combinatorial interactions of MYB and bHLH in flavonoid biosynthesis and their function in plants

MYB and basic helix-loop-helix (bHLH) are two important transcription factor (TF) families found in plants and animals. MYB-bHLH interactions control multiple enzymatic steps in flavonoid (anthocyanin and proanthocyanidin) biosynthesis pathway in plants. Moreover, they play roles in trichome and root hair formation, activation of vacuolar acidification, phytochrome A signaling, glucosinolate biosynthesis and abscisic acid (ABA) regulated gene expression. This review provides an insight into flavonoid biosynthesis by the interactions of MYB and bHLH TFs and their multitude biological functions that are important for various fundamental aspects of plant biology.