BrDDB1A promoted flowering via age pathway in Chinese cabbage.

The transition from vegetative to reproductive growth, marked by flowering, is a pivotal developmental switch in plants, whereby the age pathway serves as an important regulatory mechanism governing this process. In this study, we screened a late-flowering mutant from EMS mutagenesis in Chinese cabbage. The late-flowering phenotype was unaffected by photoperiod, vernalization and GA3 treatments, and obvious changes occurred at the transcriptional levels of age flowering pathway-related genes, which indicated that the mutant trait was mediated by the age pathway. Causal gene BrDDB1A, involved in UV-induced DNA damage recognition and repair, was identified via MutMap and KASP techniques, and its function was verified by sequencing analysis of two allelic mutants. BrDDB1A was located in the nucleus. UV-B delayed the flowering time of the WT but not that of the mutant, suggesting BrDDB1A was involved in UV-B-mediated flowering delay of Chinese cabbage.