The Histone Methyltransferase OsSET37 Positively Regulates Rice Seed Vigor

Seed vigor is a critical determinant of crop establishment and yield, yet the epigenetic mechanisms underlying this trait remain largely unexplored. Here, we identified a histone methyltransferase, OsSET37, and characterized its essential role in regulating seed vigor in rice (Oryza sativa). Consistent with OsSET37 being a member of the SDG (SET domain group) family, our results demonstrate that the loss of OsSET37 leads to a marked decrease in H3K36me3 in vivo. Phenotypic analysis showed that osset37 mutants displayed normal vegetative and reproductive growth, but exhibited delayed germination and enhanced sensitivity to salt, drought, and ABA stresses during seed germination relative to the wild type. Y2H (Yeast two-hybrid) assays demonstrated that OsSET37 interacts with stress-responsive proteins OsSUB1C and OsDIP1. Furthermore, transcriptome analysis and qRT-PCR indicated that OsSET37 modulates the expression of key genes involved in the GA (gibberellin) and ABA (abscisic acid) signaling pathways. Collectively, our findings suggest that OsSET37 positively regulates seed vigor by modulating H3K36me3 deposition and fine-tuning the hormone signaling network, highlighting its potential as a valuable target for rice breeding programs aimed at improving stress resilience.