A R2R3-MYB transcription factor, FeR2R3-MYB, positively regulates anthocyanin biosynthesis and drought tolerance in common buckwheat (Fagopyrum esculentum).

The R2R3-MYB transcription factors (TFs) play a crucial role in regulating plant secondary metabolism and abiotic stress responses, yet they are still poorly understood in common buckwheat (Fagopyrum esculentum), a valuable minor grain crop resource. In this study, a candidate gene, FeR2R3-MYB, was cloned from the anthocyanin-rich common buckwheat variety 'QZZTQ'. FeR2R3-MYB was found to contain two MYB DNA-binding domains and be located at the nucleus with transcriptional activation activity. Molecular analysis indicated that FeR2R3-MYB is predominantly expressed in flowering tissue and is highly responsive to environmental factors such as light, drought, and cold. In addition, the promoter of FeR2R3-MYB showed a positive correlation with fragment length. Further functional analysis suggested that FeR2R3-MYB not only participates in the anthocyanin biosynthetic pathway by interacting with leucoanthocyanidin reductase (FeLAR), but also enhances drought tolerance in common buckwheat. To sum up, FeR2R3-MYB exhibits positive effects on both pigment production (e.g., anthocyanin) and abiotic stress resistance, providing valuable insights for future research in buckwheat molecular breeding and resource development.