Molecular Evaluation of the Effects of FLC Homologs and Coordinating Regulators on the Flowering Responses to Vernalization in Cabbage ( Brassica oleracea var. capitata ) Genotypes

The flowering loci of cabbage must be understood to boost their productivity. In this study, to clarify the flowering mechanisms of cabbage, we examined the three flowering repressors , and , and the flowering regulators , , and of early (CAB1), middle (CAB3), and late (CAB5) flowering cabbage genotypes. Analysis of allele-specifically amplified genomic DNA and various sequence alignments demonstrated that maximal insertions and deletions influenced cabbage flowering behavior, notably in CAB3 and CAB5. Phylogenetic studies showed that , , and in the CAB1, 3, and 5 genotypes had the highest homologies to other species, with CAB3 and 5 the most similar. Although CAB3 and CAB5 have comparable genetic patterns, flowering repressors and flowering regulators were investigated individually with and without vernalization to determine their minor flowering differences. The expression investigation revealed that vernalized CAB5 downregulated all genes compared to CAB3 and, in contrast, CAB3 exhibited upregulated . We hypothesized that the CAB3 locus' additional insertions may have led to overexpression and downregulation. This study sheds light on cabbage genotypes-particularly those of CAB1 and CAB5-and suggests that structural variations in and bind flowering regulators, such as , which may affect cabbage flowering time.