RNA-Binding Protein OsGRP3 Positively Regulates Rice Storability.

Seed aging during storage represents a major challenge to global food security and germplasm resource conservation. Long-lived mRNAs, which are crucial for initiating germination after storage, have poorly understood regulatory mechanisms governing their stability. In this study, we identify the RNA-binding protein OsGRP3 as a key positive regulator of rice storability. Initially, we demonstrated that Arabidopsis AtGRP7 enhances seed vigor following aging. Phylogenetic analysis identified OsGRP3 as its closest rice homolog. Two independent OsGRP3-overexpression lines showed markedly improved germination rates and seed viability after extended artificial aging. Physiological assessments indicated that OsGRP3 mitigates aging-related damage, as evidenced by reduced malondialdehyde (MDA) levels and electrolyte leakage, consistent with better membrane integrity. RNA-seq analysis revealed that OsGRP3 overexpression attenuated the transcriptional disruption induced by aging. Moreover, under non-stress conditions, OsGRP3 directs a transcriptional program involving 404 genes implicated in DNA replication, gluconeogenesis, and essential amino acid metabolism. This reprogramming correlates with a state of heightened stress preparedness, exhibiting a pattern of correlated transcriptional regulation. Our findings establish OsGRP3 as a conserved RNA-binding protein that enhances seed storability, and offer a promising genetic target for improving storage tolerance in rice.