The GW2-ERF115-SLRL2 module regulates seed dormancy in rice

Pre-harvest sprouting (PHS), caused by weak seed dormancy and environmental stimuli, leads to significant losses in both crop yield and grain quality. Breeding crop cultivars with enhanced PHS resistance represents a promising strategy to address this challenge. However, limited useful genetic resources has hindered the progress in rice molecular breeding. Through screening of a rice mutant library, we identify the ethylene response factor115 (erf115) mutant, which exhibits enhanced PHS resistance. Genetic analysis reveals that ERF115 functions as a negative regulator of seed dormancy. Mechanistic assays show that the E3 ubiquitin-protein ligase Grain Width 2 (GW2) interacts with and ubiquitinates ERF115, thereby promoting its proteasomal degradation. Accordingly, gw2 mutants display increased PHS susceptibility. ERF115 also interacts with the transcription factor SLR1-like 2 (SLRL2) and represses its transcriptional activation activity, consequently reducing the expression of the dormancy gene Mother of FT and TFL1 like 2 (MFT2). Haplotype analysis identifies three major ERF115 haplotypes (HapI-HapIII), among which ERF115^Hapl represents an elite allele associated with reduced PHS. Collectively, our findings reveal a GW2-ERF115-SLRL2 regulatory module that integrates ubiquitin-mediated regulation and hormone signaling to fine-tune rice seed dormancy, providing valuable genetic resources for breeding PHS-resistant rice varieties.