芝麻产量相关性状的全基因组关联分析

Sesame is a traditional specialty oil crop. Because of the high nutritional and economic value, market demand of sesame increases every year. However, low yield of sesame had limited the development of sesame industry. It is significant of genetic research for sesame yield improvement. Since yield is a complex quantitative trait, sesame yield traits research had made little progress. Genome-wide association analysis is a fast and accurate method for locating quantitative trait genes and it greatly improves the efficiency of quantitative trait gene mapping. Three hundred and thirty accessions of sesame had been selected from more than 6000 sesame germplasm and resequencing of them would be carried out based on the complete of sesame genome sequencing. Yield traits of the 330 sesame accessions would be accurate identified in several environments and genome-wide association studies would be done to excavate yield-related SNP and loci. Based on previous research of yield related genes in mode plants, yield-related genes and alleles in sesame would be identified by homology analysis and genetic basis of sesame yield traits would be analyzed. Moreover, molecular markers of yield related genes would be developed. All these work would provide theoretical support for accelerating sesame yield breeding.

芝麻是我国传统特色油料作物，营养和经济价值较高，市场需求逐年上升，但芝麻单产水平较低，限制了芝麻产业发展。开展芝麻产量性状的遗传改良研究，发掘、定位产量性状相关基因，对于提高芝麻生产水平具有重要意义。产量性状是复杂的数量性状，芝麻产量性状研究进展缓慢。全基因组关联分析是快速、准确定位数量性状基因的重要方法，可大大提高产量等数量性状基因定位的效率。本项目前期从6000多份芝麻资源中逐级筛选，结合SSR鉴定，构建了包含330份材料的自然群体，拟在已完成芝麻基因组测序的基础上对该自然群体进行全基因组重测序，通过多点鉴定对芝麻产量相关性状进行全基因组关联分析，发掘与芝麻产量性状相关的SNP和基因位点。通过同源分析鉴定产量性状相关基因，发掘芝麻产量性状相关优异等位基因，解析芝麻产量构成遗传基础，并开发分子标记，为加快芝麻高产育种提供理论和技术支持。

项目从7000多份芝麻资源中逐级筛选，结合地理来源、表型和SSR鉴定，构建了包含705份材料的芝麻核心种质。采用高通量测序技术对芝麻核心种质进行全基因组重测序，获得SNP位点540万个，构建了高密度芝麻单倍型图谱。通过种质间亲缘关系分析，揭示了世界芝麻种质驯化为南北两大遗传类型。在四个生态地点考察了核心种质的产量、品质等主要农艺性状56项，基于全基因组关联分析发掘与主要农艺性状相关的SNP位点549个。通过基因功能注释、同源分析、基因表达分析等方法从显著关联位点所在的区间中发掘出46个芝麻主要农艺性状相关的基因。进一步结合重组群体的连锁分析和基因功能分析，对芝麻种皮颜色和每叶腋蒴果数等性状相关基因进行了验证。含油量遗传分析表明种皮颜色控制基因SiPPO和木质素合成基因SiNST1也影响芝麻种子含油量，为油料作物含油量的遗传改良提供了新思路。完成了两个芝麻地方品种的基因组测序组装，发现了重要基因的“大效应变异”，解析了芝麻早花的分子机制。整合项目产生的基因信息和其他已发表的数据，创建了变异组和功能基因组数据库，为芝麻研究提供了基因信息应用共享平台。开发了芝麻功能标记，应用于芝麻分子辅助选择育种，提高了芝麻定向育种效率。相关研究结果在Nature Communications等杂志上发表论文6篇，获授权发明专利2项。