The ZmbHLH47-ZmSnRK2.9 Module Promotes Drought Tolerance in Maize

Drought stress globally poses a significant threat to maize ( L.) productivity and the underlying molecular mechanisms of drought tolerance remain elusive. In this study, we characterized ZmbHLH47, a basic helix-loop-helix (bHLH) transcription factor, as a positive regulator of drought tolerance in maize. expression was notably induced by both drought stress and abscisic acid (ABA). Transgenic plants overexpressing displayed elevated drought tolerance and ABA responsiveness, while the mutant exhibited increased drought sensitivity and reduced ABA sensitivity. Mechanistically, it was revealed that ZmbHLH47 could directly bind to the promoter of gene, a member of the subgroup III SnRK2 kinases, activating its expression. Furthermore, -overexpressing plants exhibited enhanced ABA sensitivity and drought tolerance, whereas the mutant displayed a decreased sensitivity to both. Notably, overexpressing in the mutant closely resembled the mutant, indicating the importance of the ZmbHLH47-ZmSnRK2.9 module in ABA response and drought tolerance. These findings provided valuable insights and a potential genetic resource for enhancing the environmental adaptability of maize.