Flower color can be applied to landscaping and identification of the purity of seeds in hybrid production. However, the molecular basis of white flower trait remains largely unknown in Brassica rapa. In this study, an F₂ population was constructed from the cross between 15S1040 (white flower) and 92S105 (yellow flower) for fine mapping of white flower genes in B. rapa. Genetic analysis indicated that white flower trait is controlled by two recessive loci, Brwf1 and Brwf2. Using InDel and SNP markers, Brwf1 was mapped to a 49.6-kb region on chromosome A01 containing 9 annotated genes, and among them, Bra013602 encodes a plastid-lipid associated protein (PAP); Brwf2 was located in a 59.3-kb interval on chromosome A09 harboring 12 annotated genes, in which Bra031539 was annotated as a carotenoid isomerase gene (CRTISO). The amino acid sequences of BrPAP and BrCRTISO were compared between two yellow-flowered and three white-flowered lines and critical amino acid mutations of BrPAP and BrCRTISO were identified between yellow-flowered and white-flowered lines. Therefore, Bra013602 and Bra031539 were predicted as potential candidates for white flower trait. Our results provide a foundation for further identification of Brwf and increase understanding of the molecular mechanisms underlying white flower formation in Chinese cabbage.

花色可用于美化和鉴定杂交生产中种子的纯度。然而，在甘蓝型油菜中，白花性状的分子基础仍然是未知的。在这项研究中，从15S1040（白花）和92S105（黄花）之间的杂交构建了一个F ₂种群，以精细定位B中的白花基因。拉帕。遗传分析表明，白花性状受两个隐性基因座Brwf1和Brwf2的控制。使用InDel和SNP标记，将Brwf1定位到A01染色体上的49.6kb区域，该区域包含9个带注释的基因，其中Bra013602编码质体-脂质相关蛋白（PAP）；Brwf2位于A09染色体上的59.3 kb间隔中，其中包含12个带注释的基因，其中Bra031539被注释为类胡萝卜素异构酶基因（CRTISO）。比较了两个黄色花系和三个白色花系的BrPAP和BrCRTISO的氨基酸序列，并在黄色和白色花系之间鉴定了BrPAP和BrCRTISO的关键氨基酸突变。因此，Bra013602和Bra031539被预测为白花性状的潜在候选者。我们的结果为进一步鉴定Brwf奠定了基础 并增加对大白菜白花形成的分子机制的了解。