Genome-wide analysis of cabbage cytochrome P450 genes and characterization of BoCYP704B1, a gene responsible for cabbage anther development

Plant cytochrome P450 monooxygenases (CYPs) make up a large superfamily of heme-thiolate enzymes involving in many primary and secondary metabolism reactions. In this study, a total of 279 Brassica oleracea CYP (BoCYP) genes were identified in the cabbage genome. These BoCYPs were classified into eight distinct clans with 44 families. Expression analyses of the BoCYP genes of different cabbage tissues suggested that some BoCYPs may play significant roles in reproduction. Recently, BoCYP704B1 has been identified as a candidate gene associated with male sterility in the cabbage line 83121A. Here, the functional mechanism of BoCYP704B1 was explored. Subcellular localization showed that BoCYP704B1 is located in the endoplasmic reticulum. RNA in situ hybridization indicated that BoCYP704B1 is predominantly expressed in the tapetum of cabbage anther, and the expression was maximal at the tetrad and early monocyte stage and weakened to the termination. Furthermore, functional complementation test results showed that BoCYP704B1 from wild type could rescue the male sterility of 83121A mutant. The results of this study increase our understanding of the functional mechanism of cabbage CYP genes and will facilitate the application of the BoCYP704B1 gene in cabbage molecular breeding.