The mungbean locus encoding MYB90, an R2R3-type MYB protein, regulates anthocyanin biosynthesis.

Anthocyanins are water-soluble pigments present in several tissues/parts of plants. The pigments provide color and are wildly known for health benefits for human, insect attraction for plant pollination, and stress resistance in plants. Anthocyanin content variations in mungbean [ (L.) Wilczek] were first noticed a long time ago, but the genetic mechanism controlling the anthocyanins in mungbean remains unknown. An F population derived from the cross between purple-hypocotyl (V2709) and green-hypocotyl (Sulv1) mungbeans was used to map the locus controlling purple hypocotyl. The locus was mapped to a 78.9-kb region on chromosome 4. Sequence comparison and gene expression analysis identified an R2R3-MYB gene as the candidate gene for the locus. Haplotype analysis using 124 mungbean accessions suggested that 10 single nucleotide polymorphisms (SNPs) in exon 3 may lead to an abolished expression of and an absence of anthocyanin accumulation in the hypocotyl of Sulv1 and KPS2. The overexpression of in mungbean hairy root, tobacco leaf, and resulted in anthocyanin accumulation (purple color). Gene expression analysis demonstrated that regulated anthocyanin accumulation in the hypocotyl, stem, petiole, and flowers, and the expression was sensitive to light. VrMYB90 protein may upregulate encoding dihydroflavonol 4-reductase at the late biosynthesis step of anthocyanins in mungbeans. These results suggest that is the dominator in the spatiotemporal regulation of anthocyanin biosynthesis. Our results provide insight into the biosynthesis mechanism of anthocyanin and a theoretical basis for breeding mungbeans.