芝麻高密度新型遗传图谱的构建及抗茎点枯病的QTLs定位

Sesame (sesamum indicum L.) is a important world-wide major oil crops. Charcoal rot is one of serious fungal diseases affecting the production of sesame, which caused by Macrophomina phaseoli ssp. Sesamica. So there have a very important significance to explore the genetic and molecular mechanisms of Charcoal rot resistance, discovery and utilize more resistance genes, and cultivate new sesame varieties with high levels of resistance. We had constructed an advanced generation populations of recombinant inbred lines by a resistant parent of "Zhongzhi 14" and a susceptible parent of "Miaoqian sesame" in this project. The genetic mechanism of Charcoal rot will be analysis through resistance identification in multi-sites trails for several years. An high-quality, high density, novel and important reference genetic linkage map of sesame will be constructed, through an high-throughput sequencing and genotyping technology of Restriction-site Associated DNA tags (RAD tags) to discover sequence polymorphism such as SNPs and InDel, together with the analysis of PCR markers such as SSR and STS derived from sesame ESTs. Then, QTLs and linked molecular markers for Charcoal rot resistance will be identified rapidly through interval mapping. This project will provide strong evidence for the genetic and molecular mechanism of sesame Charcoal rot resistance. It also will provide strong support for genetic improvement of important agronomic traits in sesame such as Charcoal rot resistance, by Marker-Assisted Selection or other molecular breeding strategies.

芝麻是世界重要的油料作物，而Macrophomina phaseoli ssp. Sesamica引起的茎点枯病是影响芝麻生产的严重真菌病害。探索茎点枯病抗性的遗传和分子机制，发掘和利用更多抗性相关基因，具有十分重要的理论和实践意义。本项目以抗病亲本"中芝14"和感病亲本"庙前芝麻"构建的高世代重组自交系群体为研究材料，通过多年多点的抗性鉴定，开展茎点枯病抗性遗传分析；利用Restriction-site Associated DNA tags高通量测序和基因分型技术高效地发掘SNP等序列多态信息，利用芝麻ESTs开发SSR等PCR标记，构建一张具有重要参考价值的高密度新型遗传连锁图谱；通过区间作图法进行茎点枯病抗性的QTLs定位，获得抗性相关分子标记。本项目将为芝麻茎点枯病抗性的遗传及分子机理阐释奠定理论基础，为芝麻茎点枯病抗性等重要农艺性状的遗传改良提供分子标记辅助选择手段。

芝麻是世界重要的油料作物，而Macrophomina phaseoli ssp. Sesamica引起的茎点枯病是影响芝麻生产的严重真菌病害。探索茎点枯病抗性的遗传和分子机制，发掘和利用更多抗性相关基因，具有十分重要的理论和实践意义。本项目以抗病亲本“中芝14”和感病亲本“庙前芝麻”构建的高世代重组自交系群体为研究材料，通过多年多点的抗性鉴定，开展茎点枯病抗性遗传分析，发现茎点枯病发病率家系间差异极显著且群体呈明显连续正态分布，为典型微效多基因控制的数量性状；利用Restriction-site Associated DNA tags高通量测序和基因分型技术高效地发掘SNP等序列多态信息，利用芝麻ESTs开发SSR等PCR标记，构建了一张具有重要参考价值的高密度新型遗传连锁图谱，该图谱包含14个连锁群、1230对标记，图谱全长844.cM，是迄今为止标记数目、类型最多和密度最高的芝麻全基因组高密度新型遗传连锁图谱；通过区间作图法MIM和复合区间作图MCIM进行RIL群体3年5个点次茎点枯病抗性的QTL扫描，获得3个茎点枯病抗性相关QTLs，其中位于LG1上的主效QTL(Qcr-1)在多个环境中均被检测到，广义遗传力为10.54%，对表型的贡献率为6.3~25.8%。此外，通过转录组测序、定制表达谱芯片和荧光定量PCR，开展抗（感）亲本以及极端抗（感）RIL家系构建的抗感池的茎点枯病病原菌侵染前后差异表达基因分析，最终筛选和验证得到300余对茎点枯病抗性相关候选基因，其中3个显著差异表达候选基因正好落在LG1主效QTL(Qcr-1)区间内。本项目将为为芝麻茎点枯病抗性相关候选基因克隆、功能分析及遗传改良奠定坚实基础和提供重要帮助。