Drought response mechanism of the Tartary buckwheat (Fagopyrum tataricum) variety ‘Dingku1’: multiple regulation of flavonoid biosynthesis by FtMYBs

Fagopyrum tataricum exhibits robust stress tolerance, while the molecular mechanisms governing its elite drought-resistant cultivars remain inadequately elucidated. In this study, different Tartary buckwheat varieties show varied drought responses; Dingku1 exhibits strong drought resistance. Further experiments and transcriptome analysis showed FtMYB family correlates with flavonoid biosynthesis under drought stress. Dual luciferase assays and yeast one-hybrid (Y1H) analyzed regulatory links between FtMYBs and key flavonoid genes. High-Performance Liquid Chromatography (HPLC) revealed quercetin and rutin changes after MYBs overexpression in hairy roots. Results indicated FtMYB78 has dual roles in phenylalanine metabolism branches, showing complex MYB regulation in Tartary buckwheat. Collectively, these findings illuminate Tartary buckwheat's drought response mechanisms, laying a theoretical basis for breeding drought-resistant varieties of this crucial crop.