Rapid identification of yellow-flowered gene Bofc in cauliflower ( Brassica oleracea var. botrytis ) by bulked segregant analysis and whole-genome resequencing

The accumulation of carotenoids is related to pigment formation in flowers and other organs. In order to elucidate the genetic variation of flower color in cauliflower, a F2 segregating population was obtained from yellow-flowered cauliflower ‘QGS’ and white-flowered Chinese kale ‘JYJ’. Bulked segregant analysis combined with the whole-genome resequencing was employed to locate the target region for Flower Color. In this study, Bofc was anchored on chromosome C03 with a single peak, and further mapped to 164 kb interval with 0.28 cM genetic distance. BoCCD4, encoding carotenoid cleavage dioxygenase 4 in the carotenoid metabolic pathway, was selected as the most likely candidate gene. Sequence analysis revealed that an insertion of a 10,608 bp CACTA-like transposon in the coding region led to the loss-of-function of the BoCCD4 gene in cauliflower. These results will provide further understanding of the genetic mechanism controlling flower color in Brassica oleracea species.