ZmDREB1A Regulates myo-Inositol-1-phosphate Synthase 2 Controlling Maize Germination at Low Temperatures

Transcription factor DREB1A positively regulates plant chilling stress tolerance. However, its role in regulating seed germination at low temperatures has remained a mystery. Our research has unveiled that maize zmdreb1a mutant seeds exhibit decreased ZmMIPS2 expression and a lower germination percentage than the control under low temperatures. The overexpression of ZmDREB1A upregulated ZmMIPS2 expression, while the mutation of DRE motifs in the ZmMIPS2 promoter nullified the influence of ZmDREB1A on the target gene expression. In addition, we demonstrated that ZmDREB1A directly binds to the three DRE motifs in the promoter of ZmMIPS2 both in vitro and in vivo. Further investigation has shown that maize zmmips2 mutant seeds are more sensitive, while ZmMIPS2 overexpressing seeds are more tolerant of low temperatures during seed germination. These findings could be applied to develop new crop varieties that are more resilient to low temperatures during the vulnerable germination phase.