A circadian clock-associated gene GmRVE8b modulates flowering time and maturity in soybean

Elucidating the regulatory mechanisms underlying flowering and maturation in soybean is essential for improving yield stability and adaptation to diverse environments. The circadian clock coordinates developmental transitions and plays a pivotal role in the regulation of reproductive development. However, the molecular mechanisms linking the circadian clock to photoperiodic and thermal responses in soybean remain poorly understood. Here, we conducted a genome-wide association study using 257 diverse soybean germplasm accessions and identified GmRVE8b, a homolog of the Arabidopsis REVEILLE gene family, as a major locus significantly associated with soybean maturity across multiple environments with contrasting photoperiod regimes. Haplotype analysis showed that accessions carrying the GmRVE8b^H3 haplotype matured significantly later than those harboring the GmRVE8b^H1. Functional validation through transgenic overexpression further demonstrated that GmRVE8b markedly delays both flowering and maturity in soybean. Quantitative real-time PCR analysis suggested that GmRVE8b may be associated with the GmELF3-E1/E1La-FT4 photoperiodic regulatory module. Collectively, our findings suggest GmRVE8b as a previously uncharacterized circadian clock-associated negative regulator of soybean flowering and maturity, providing a promising genetic resource for molecular breeding to improve soybean adaptation across latitudes and under variable photothermal conditions.