中国芜菁抗根肿病基因的精细定位

Clubroot disease was a worldwide cruciferous disease, which caused by Plamodiophora brassicae Woron, a serious soil borne disease, damage the cultivation and production of Brassica crops, especially Chinese cabbage vegetables. However, most of the Chinese cabbage seeds are mainly monopolized by Japan, South Korea, Europe, and America etc. The main resistance gene germplasms are from European turnip. The clubroot resistance gene germplasms with independent intellectual property rights in our country are less. Based on this study, our research group has collected and evaluated many Chinese cabbage germplasm resources, and has a unique Chinese turnip resistance source. Its resistance locus is different from the 16 published loci, and the resistance is durable. In this study, the F2 population, which was constructed crossed Chinese turnip inbred line BrT60 (clubroot resistant line) with Chinese cabbage DH line Y177-47 (clubroot susceptible line), as materials, first of all, based on the BSA method combined with Next Generation Sequencing technology, named QTL-Seq technology by detecting the SNP sites of initial resistance genes. And further integrated with BSR-Seq technology, meanwhile, with greater secondary separation population as materials, finding the recombinant plant by using the developed molecular marker based on re-sequencing data of parents, finally fine mapping of clubroot resistance gene, and applied to breeding improvement. The results will provide excellent gene resources and theoretical support for the breeding of Chinese cabbage and cruciferous crops in the breeding of anti-clubroot disease.

根肿病是由芸薹根肿菌侵染引起的一种世界性十字花科土传病害，严重危害芸薹属作物，特别是白菜类蔬菜的栽培生产。然而，国际上抗根肿病白菜种子主要由日韩欧美等国垄断，抗源主要来自欧洲芜菁，我国自主知识产权的抗源较少。本研究针对这种情况，项目组长期收集、评价，保存独特中国芜菁根肿病抗源，其抗性位点不同于已发表的16个，而且抗性持久。本研究以高抗根肿病自交系中国芜菁BrT60和高感大白菜DH系Y177-47为亲本所构建的F2群体为材料，首先，利用基于BSA法结合高通量全基因组重测序原理的QTL-Seq技术，通过检测SNP差异位点进行抗性基因初定位，进一步结合BSR-Seq技术，以更大的次级分离群体群体为材料，利用初定位结果和父母本重测序及RNA测序数据开发的分子标记进行重组单株筛选，最终实现抗根肿病基因的精细定位，并应用于品种改良。研究结果将为白菜及十字花科作物抗根肿病育种提供优异基因资源和理论基础。

根肿病是由芸薹根肿菌侵染引起的一种世界性十字花科土传病害，严重危害芸薹属作物，特别是白菜类蔬菜的栽培生产。然而，国际上抗根肿病白菜种子主要由日韩欧美等国垄断，抗源主要来自欧洲芜菁，我国自主知识产权的抗源较少。本研究针对这种情况，项目组长期收集、评价，保存独特中国芜菁根肿病抗源，其抗性位点不同于已发表的19个，而且抗性持久。本研究以高抗根肿病自交系中国芜菁BrT18-6和高感大白菜DH系Y510-9为亲本所构建的F2群体为材料，首先，利用基于BSA法结合高通量全基因组重测序原理的QTL-Seq技术，通过检测SNP差异位点进行抗性基因初定位，结合 SNP-index 曲线与卡方分布的结果，我们在染色体A08上发现了潜在的候选区域，位于染色体的12.50-16.10 Mb。进一步结合BSR-Seq技术，以更大的次级分离群体群体为材料，利用初定位结果和父母本重测序及RNA测序数据开发的分子标记进行重组单株筛选，最终实现抗根肿病基因的精细定位，在A08染色体候选区域内共设计了40个标记。以BrT18-6、Y510-9和F1为模板筛选引物多态性，共筛选出23条可行引物，之后在F2群体进行多态性分析。分析结果用JoinMap 4.0进行连锁，构建A08染色体部分连锁遗传图谱。结果表明，基因定位在PC1414和PA02之间，遗传距离分别为0.1cM和9.1cM，候选区域的范围成功缩小到12.7-13.2 MB (0.5MB)。在此区间内有两个串联抗性基因，BraA08g015910及BraA08g015920，为根肿病抗性基因候选基因。基于此开发的分子标记应用于材料选择，进而进行品种改良。在项目实施期间，撰写、标注发表研究论文4篇，其中SCI收录2篇；申请发明专利3项，获得授权1项；培养大学实习生2名。研究结果将为白菜及十字花科作物抗根肿病育种提供优异基因资源和理论基础。