Maize SERRATE 1B positively regulates seed germinability under low-temperature

Low temperature poses a significant threat to seedling emergence after maize sowing. While the impact of SERRATE (SE) on plant development via RNA processing has been extensively reported, its involvement in transcriptional regulation or the formation of low-temperature germination ability remains unclear. Our previous research revealed that ZmSE1B is located at the overlapping region of qLTGR4-1 or qLTPRL4-1, which has been associated with low-temperature germination by QTL analysis using IBM Syn4 RIL population. In the present study, we observed that maize seeds overexpressing ZmSE1B exhibited enhanced germination percentages, longer roots, and longer shoots when subjected to low-temperature conditions compared to the wildtype. Through an integrated analysis of RNA-Seq and CUT&Tag, we speculated that ZmGRXCC17, which encodes a GLUTAREDOXIN, may be upregulated by ZmSE1B in maize germinated seeds at low-temperature. Further, the regulation of ZmSE1B on transcription of ZmGRXCC17 was validated using dual-luciferase reporter system and CUT&Tag-qPCR. Finally, the positive effect of ZmGRXCC17 on low-temperature tolerance during seed germination was elucidated through its heterologous expression in rice. The results indicate that ZmSE1B enhances the seed germination ability under low temperature by regulating the transcription of ZmGRXCC17.