The ERF072 Transcription Factor Directly Regulates MtSOC1-Like Expression and Mediates Drought-Accelerated Flowering in Medicago truncatula.

Flowering time is a key agricultural trait that indicates the yield of Medicago truncatula. Although drought stress affects flowering time in this species, the molecular mechanism underlying the enhancement of flowering to facilitate drought tolerance remains unclear. Accelerated flowering at the onset of drought enables drought escape in Medicago truncatula, ethylene-responsive factors are an important class of transcription factors whose members are involved in drought stress processes in numerous plants. In this study, MfERF072 overexpression accelerated flowering in Medicago truncatula. In addition, the knockdown of this gene did not affect flowering time, MfERF072 overexpression enhanced drought and decreased the flowering time of Medicago truncatula under drought stress. Moreover, a more pronounced phenotype was observed. In contrast, the knockdown of this transcription factor reduced drought tolerance and delayed flowering time. Furthermore, yeast one-hybrid and two-luciferase assays confirmed that ERF072 binds directly to the promoter of the flowering integration MtSOC1-like gene in Medicago truncatula. This consequently promotes floral transition under drought conditions. Our preliminarily data revealed that ERF072 regulates flowering under drought stress. These results may provide insights into new genetic resources for the molecular breeding of Medicago truncatula, ultimately supporting stress tolerance by balancing drought stress responses and flowering time.