芝麻耐湿性QTL精细定位及候选基因筛选

Waterlogging is the main factor affecting the development of sesame production and the improvement of sesame yield in China, no significant breakthrough has been achieved in waterlogging tolerance breeding. This project aims to combine association analysis and linkage mapping in fine mapping of sesame waterlogging tolerance QTL, then screen out and identify important candidate genes. The 500 germplasm resources of sesame core collection will be used as association analysis population, after analyzing by SSR markers designed from reference sequence of sesame genome, the genome-wide association analysis of genotype and phenotype will be carried out, and markers significantly associated with waterlogging tolerance in germination period will be detected, then these markers and their adjacent markers will be used in analysis of F2 genotype, and linkage analysis will be carried out using F2 genotype and F2:3 phenotype, the waterlogging tolerance QTL with main effect in germination stage will be mapped in the range of about 100 to 300kb or 0.4 to 1.2cM, according to the functional annotation, important candidate genes will be screened out. Topic of this research is around the key technology problem of sesame production in China, the materials have been prepared, and with the genome physical map and other advanced technology platform and adequate work foundation, research plan will be the first time adopted in sesame. The results will provide important theory basis and practical application basis for breakthrough of waterlogging tolerance genetic improvement of sesame variety in China, and to obtain the research productions with independent intellectual property.

湿害是影响我国芝麻生产发展和单产提高的主要障碍因素，长期以来耐湿育种未取得显著突破。本项目拟采用关联分析和连锁作图联合的方法开展芝麻耐湿性的QTL精细定位，筛选、鉴定重要的候选基因。利用已构建的500份核心种质群体，基于芝麻基因组参考序列设计的均匀分布的SSR标记进行全基因组关联分析，获得发芽期耐湿性显著关联标记，并连同其附近标记用于耐湿/敏感F2群体基因型分析，结合F2:3家系表型进行连锁分析，将发芽期耐湿性主效QTL精细定位于芝麻基因组100-300kb或0.4-1.2cM范围内，依据功能注释筛选重要候选基因。本研究围绕我国芝麻生产中的关键科技问题进行选题，材料准备充分，具备基因组物理图谱等先进技术平台和充分的工作基础，采用的研究方案在芝麻上尚属首次，研究结果将为我国芝麻品种耐湿性改良取得突破提供重要理论和实际应用基础，并将获得自主知识产权研究成果。

湿害是影响我国芝麻生产发展和单产提高的主要障碍因素，长期以来耐湿育种未能取得显著突破。本项目首次采用关联分析和连锁作图联合的方法进行了芝麻耐湿性的QTL精细定位，并筛选出重要候选基因。利用已构建的500份核心种质群体作为关联分析群体，对其进行发芽期耐湿性鉴定，利用基于芝麻基因组参考序列设计的均匀分布的291个SSR标记（平均间距小于5cM）对其进行基因型分析，通过全基因组关联分析获得11个发芽期耐湿性显著关联标记（P＜0.05），将这些标记连同其附近737个标记用于中芝13与ZZM4508多态性筛选，得到67个多态性标记，用于两者构建的耐湿/敏感F2群体基因型分析，并结合其F2:3家系表型进行连锁分析，最终将发芽期耐湿性主效QTL（qWTG3-1）精细定位于第3连锁群的13686718至13966025之间约279kb基因组区段内，LOD值10.7，加性效应9.43，能够解析14.84%的表型变异，软件预测表明该基因组区段内共有36个基因，依据功能注释和已有转录组信息筛选出3个重要候选基因（SIN-1021942，SIN_1021952和SIN_1021964）。研究结果将为我国芝麻品种耐湿性遗传改良取得突破提供重要理论和实际应用基础。