BrWSD1 links wax metabolism with cold-induced flowering in Chinese cabbage

Flowering time is strongly influenced by environmental conditions, yet the contribution of metabolic pathways to vernalization-induced floral transition remains poorly understood. Here, we identify a wax-associated acyltransferase gene, BrWSD1, as a cold-responsive regulator of flowering in Chinese cabbage. Transcriptomic and metabolomic analyses showed that prolonged cold enhanced both BrWSD1 expression and cuticular wax accumulation. Functional assays demonstrated that overexpression of BrWSD1 accelerated bolting and flowering, whereas virus-induced silencing delayed floral transition, accompanied by reduced expression of the floral integrator FT. Subcellular localization and protein-protein interaction assays further revealed that BrWSD1 physically interacts with the CONSTANS-like transcription factor BrCOL3, suggesting an unexpected crosstalk between wax metabolism and flowering regulators under vernalization conditions. Together, these findings suggest that wax metabolism, beyond serving as a structural barrier, may contribute to flowering regulation in response to prolonged cold. This work highlights a metabolic-transcriptional interface that broadens our understanding of how environmental cues shape reproductive development in Brassicaceae crops.