Seed dormancy and germination represent an intricately linked yet biologically antagonistic relationship, which balances seed development progression with pre-harvest sprouting (PHS) resistance. However, the molecular mechanisms underlying the transition from dormancy to germination remain largely unknown. In this study, we investigate the regulatory role of SIMILAR TO RCD 1 (SRO1), which cooperates with HISTONE DEACETYLASE INTERACTING WITH SRO1 (HIS1) to fine-tune this transition in wheat (Triticum aestivum). TaSRO1 functions as an enhancer of germination through interacting with ABA INSENSITIVE 5 (ABI5), suppressing its transcription capacity to dormancy-promoting targets. Epistatic analysis indicates that TaABI5 positively regulates seed dormancy in a copy number-dependent manner, whereas TaSRO1 functions through ABA signaling by acting upstream of TaABI5. Furthermore, TaSRO1 recruits TaHIS1 to the promoters of TaABI5 target genes, leading to epigenetic erasure of histone acetylation marks and subsequent suppression of TaABI5-mediated transactivation. These findings uncover an epigenetic mechanism wherein TaSRO1 precisely orchestrates the developmental phase transition from dormancy to germination, thereby offering potential targets for enhancing PHS resistance in wheat.
Liu et al. (2026) studied this question.