The antagonistic regulation of PlDAM and PlSOC1 coordinates flowering under low temperature in herbaceous peony

Flowering is a fundamental developmental process that determines reproductive success and environmental adaptation in plants; however, the molecular basis of flowering time regulation, particularly in perennial species, remains incompletely understood. Herbaceous peony ( Paeonia lactiflora ) exhibits substantial variation in flowering time among cultivars, providing an excellent system for investigating the regulation of flowering time. In this study, flower bud differentiation was compared among early-, mid-, and late-flowering cultivars using histological, physiological, transcriptomic, and functional analyses. Flower bud differentiation progressed more rapidly in the early-flowering cultivar and was accompanied by enhanced carbohydrate accumulation, reduced reactive oxygen species levels, and elevated expression of PlSOC1 . Overexpression of PlSOC1 in Arabidopsis accelerated flowering and was accompanied by reduced hydrogen peroxide accumulation, increased soluble sugar content, and increased expression of genes associated with carbohydrate metabolism and stress responses. In contrast, PlDAM physically interacts with PlSOC1 and displays an antagonistic expression pattern during flower bud differentiation. PlDAM overexpression in Arabidopsis delayed flowering, increased oxidative stress, reduced sugar accumulation, and impaired reproductive development. This study provides insights into the molecular basis of flowering-time variation in herbaceous peony and highlights the PlDAM–PlSOC1 module in low-temperature-mediated flowering regulation.