ZmDREB1A Regulates <i>myo</i>-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 <i>zmdreb1a</i> mutant seeds exhibit decreased <i>ZmMIPS2</i> expression and a lower germination percentage than the control under low temperatures. The overexpression of ZmDREB1A upregulated <i>ZmMIPS2</i> expression, while the mutation of <i>DRE</i> motifs in the <i>ZmMIPS2</i> promoter nullified the influence of ZmDREB1A on the target gene expression. In addition, we demonstrated that ZmDREB1A directly binds to the three <i>DRE</i> motifs in the promoter of <i>ZmMIPS2</i> both in vitro and in vivo. Further investigation has shown that maize <i>zmmips2</i> mutant seeds are more sensitive, while <i>ZmMIPS2</i> 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.