芝麻抗裂蒴性基因的精细定位和候选基因鉴定

Capsule dehiscence and seed loss are prevalent in sesame varieties，which are important factors restricting the yield and mechanized production. The fine mapping,cloning of shatter resistant gene and molecular mechanism of shatter resistance formation in sesame remain to be blank, which affects the shatter resistance cultivar selection. We have developed a set of near-isogenic lines of shatter resistance from the cross between UCR15 and Yuzhi 11,and an F2 segregating population derived from the cross near-isogenic lines were obtained. This is the first report of use of near-isogenic lines for fine mapping and cloning the genes of shatter resistance. The objectives of the present study are as follows:(1)to screen the strong association SNP molecular markers by conducting whole-genome SNP discovery and quantitatively genotype of BSA samples through the Super BSA method;(2)to confirm and obtain the fine mapping regions of the SNP markers of strong association using F2 populations (3000-5000 strains);(3)to identify candidate genes by the biological information of the sesame genome sequencing，gene function prediction and the qRT-PCR. The results will lay the foundation for cloning shatter resistance gene of sesame, explaining the molecular mechanism for the formation of shatter resistance, and breeding suitable varieties with shatter resistance.

裂蒴落粒在芝麻品种中普遍存在，是制约芝麻产量和机械化生产的重要因素。目前，关于芝麻抗裂蒴性基因的精细定位、克隆及裂蒴形成的分子机理还处于空白阶段，这影响了抗裂蒴性品种的选育。我们利用外引的闭蒴品种"UCR15"作供体亲本，与"豫芝11号"杂交和连续回交，获得了抗裂蒴性的近等基因系，并构建了F2分离群体。本研究，将利用近等基因系和F2群体为材料:(1)通过F2群体裂蒴性鉴定,挑选极端裂蒴和抗裂蒴植株构建混合基因池，采用Super BSA法进行关联性SNP分子标记的快速筛选；(2)对强关联的SNP标记利用F2大群体(3000-5000株)进行验证筛选，获得抗裂蒴性基因的精细定位区域；(3)结合芝麻基因组测序的生物学信息和基因功能预测，确定候选基因，通过qRT-PCR在表达水平筛选目标基因，并分析基因的时空表达特点。研究结果将为克隆抗裂蒴性基因，明确裂蒴形成的分子机理，选育抗裂蒴品种奠定基础。

裂蒴落粒在芝麻品种中普遍存在，是制约芝麻产量和机械化生产的重要因素。克隆控制抗裂蒴性的基因对解析芝麻抗裂蒴性机制具有重要意义。本研究利用抗裂蒴性材料和裂蒴材料构建的F2分离群体，通过裂蒴性鉴定，挑选极端裂蒴和抗裂蒴植株构建混合基因池，采用Super BSA 法进行关联标记筛选，对强关联的SNP标记利用F2大群体(5000株)进行验证筛选，逐渐缩小定位区间，把控制抗裂蒴性的基因精细定位到39kb区间，基因组信息注释后，获得了候选基因KAN1。抗裂蒴和裂蒴材料基因序列比对发现，抗裂蒴材料第一个外显子和第一个内含子连接处的14bp序列缺失，抗裂蒴材料缺少第二个外显子，翻译提前终止，丧失基因功能。抗裂蒴基因的克隆对解析芝麻抗裂蒴性形成的分子机制及抗裂蒴分子育种具有重要意义。