AcMYB1 Interacts With AcbHLH1 to Regulate Anthocyanin Biosynthesis in .

is one of the most popular foliage plants with abundant leaf phenotypes; therefore, anthocyanin coloration is a vital economic trait in . However, the molecular mechanisms underlying anthocyanin biosynthesis and its regulation remain unclear. In this study, and , transcription factor genes related to an R2R3-myeloblast (MYB) and a basic helix-loop-helix (bHLH), respectively, were isolated from "Red Valentine" and functionally characterized. AcMYB1 and AcbHLH1 were found to interact by Y2H and BiFC assay. was grouped into the AN2 subgroup and shared high homology with the known regulators of anthocyanin biosynthesis. Gene expression analysis showed that both and have similar expression patterns to anthocyanin structural genes and correlate with anthocyanin distribution in different tissues of . Light strongly promoted anthocyanin accumulation by upregulating the expression of anthocyanin-related genes in leaves. Ectopic expression of in tobacco remarkably increased anthocyanin accumulation in both vegetative and reproductive tissues at various developmental stages. These results provide insights into the regulation of anthocyanin biosynthesis in and are useful for breeding new cultivars with enhanced ornamental value.