The HD-Zip transcription factor FaANL2 represses FaMYB10 to inhibit anthocyanin biosynthesis in strawberry fruit

HD-ZIP proteins play multifaceted roles in plant development and stress responses. In this study, FaANL2 was found to respond to light stimuli and phytohormones, including abscisic acid (ABA) and auxin, which in turn negatively correlate with anthocyanin accumulation in strawberry fruit (Fragaria x ananassa). In strawberry fruit development and ripening process, the transcriptions of FaANL2 were attenuated and correlating with increased anthocyanin content. Dual-luciferase assays indicated that FaANL2 significantly repressed the promoter activity of FaMYB10, the master activator of anthocyanin biosynthesis. Yeast one-hybrid and electrophoretic mobility shift assays showed that FaANL2 could directly bind to the promoter of FaMYB10. Transient overexpression of FaANL2 in strawberry fruit significantly decreased FaMYB10 expression and anthocyanin production. In contrast, transient RNAi of FaANL2 resulted in increases in FaMYB10 expression and anthocyanin content. These results demonstrated that FaANL2, which is influenced by light and phytohormones, suppressed anthocyanin accumulation in strawberry via direct downregulation of FaMYB10.