抽薹是大白菜由营养生长转向生殖生长的关键发育环节。创制早/晚抽薹突变体和解析突变基因功能，是揭示抽薹分子调控机制的重要途径。在前期研究中，申请者通过3750个EMS诱变株系筛选，鉴定得到1个晚抽薹突变体，抽薹时间较野生型推迟约25天。遗传和重测序分析表明，其晚抽薹性状由单隐性基因控制（命名为lbm1），已知抽薹开花基因均未发生突变。申请者已利用野生型和突变体构建了F2分离群体及其F3家系。本项目拟采用MutMap策略和KASP标记定位突变基因；借助功能互补验证和CRISPR/Cas9技术，确认突变基因；结合亚细胞定位、启动子活性分析等技术详细分析该基因的表达模式；利用酵母双杂交、EMSA、ChIP-seq、转录组测序等技术，分离鉴定该基因的上下游基因及互作蛋白，探讨与已知抽薹基因调控网络的关系。本项目成果将为进一步揭示植物抽薹开花分子机制提供素材，也可为耐抽薹品种选育提供一定的理论依据。

Bolting is the key developmental event in the switch from vegetative to reproductive growth in Chinese cabbage. The effective approach of exploring the regulatory mechanism of bolting was to create bolting-related mutants and verify the function of mutant genes. In our previous study, the applicant obtained a late-bolting mutant by screening 3750 strains of EMS mutagenesis, and the bolting time of the mutant is delayed by approximately 25 days compared to the wild type. Genetic and re-sequencing analysis revealed that the late bolting trait was controlled by a single recessive gene, designated as lbm1, and no mutation were found in the known bolting-related genes. F2 segregating population and F3 population were constructed using the late-bolting mutant and the wild type. In this project, the mutant gene lbm1 will be mapped using MutMap strategy and KASP marker. The mutant gene lbm1 will be confirmed by functional complementary verification and CRISPR/Cas9 technology. The expression pattern of lbm1 will be analyzed by combining subcellular localization and promoter activity analysis. The upstream and downstream genes and the interaction proteins of lbm1 will be isolated and identified using yeast two-hybrid, EMSA, ChIP-seq and transcriptome sequencing technology, and the relationship between lbm1 and the regulatory network of the known bolting-related genes will be explored. These research results will provide the materials for further revealing the molecular mechanism of bolting, and lay a certain theoretical foundation for variety breeding of the late bolting in Chinese cabbage.