ROOT INITIATION DEFECTIVE 1 regulates seed germination through transcription rather than alternative splicing in a temperature-dependent manner.

Timely seed germination is a crucial process for plant survival and subsequent propagation, which is significantly impacted by high temperatures. ROOT INITIATION DEFECTIVE 1 (RID1), an Arabidopsis DEAH/RHA RNA helicase, has been previously reported to modulate the cellular specification of mature female gametophyte and callus initiation from hypocotyl explants through proper alternative splicing. However, the role of RID1 in the regulation of seed germination remains largely unexplored. Here, we identified that mutations in RID1 delayed seed germination more severely at 28℃ compared to 22℃. Notably, we found that the rid1-1 mutation did not significantly alter genome-wide alternative splicing patterns during seed germination compared to the wild type. Further evidences demonstrated that RID1 regulates seed germination via the abscisic acid (ABA) pathway by physically and genetically interacting with the SKIP-associated transcriptional complex. These results suggest that RID1 regulates seed germination in response to ambient temperature at the transcriptional level rather than through alternative splicing regulation. This study provides novel insights into the mechanisms underlying the regulation of seed germination.