全基因组关联分析鉴定控制油菜种子低积累重金属镉的关键基因

Heavy metal pollution in soil has been becoming a global problem, which is seriously threatening the safety of crop production. The moderated- and serious-polluted lands in China have already reached more than 50 million mu, and Cadmium is as one of the most widely and the most poisonous heavy metal pollutants. Excessive intake of Cd will lead to severe illness in human beings, such as prostate cancer. The ability of Cd accumulation in plants is remarkably varied among different species and even presenting significant genetic variation within a species. As the trait of low Cd accumulation is heritable and controlled by a major gene, therefore exploitation novel gene resources with low Cd accumulation and breeding new Cd resistant cultivars is an effective way to cope with as well as prevent the Cd pollution and its toxicity. Brassica napus L. is the most significant oilseed crop and its seeds are the main resource of edible vegetable oil in China, hence, it is of great importance to prevent or eliminate the Cd pollution in the production of rapeseeds. In this project, we decided to take full advantage of the rich genetic resources of Brassica crops in China to exploit elite germplasms with low Cd accumulation via high-throughput screening, and we also intended to apply the newly established Genome-Wide Association Study (GWAS) platform of rapeseed to identify the key genes controlling low Cd accumulation as well as to elucidate the genetic, physiological and molecular basis of the low Cd accumulation in Brassica napus L., ultimately develop functional genetic markers for molecular design breeding and provide scientific guidance and advanced techniques to breed new and safety Cd tolerance cultivars of Brassica napus L.

土壤重金属污染已成为严重威胁作物安全生产的全球性问题，我国中度、重度污染土地已达5000万亩以上，其中镉是最为普遍、毒性最严重的重金属污染物之一，过量摄入镉会导致前列腺癌等严重疾患。植物积累镉存在显著的物种间和物种内遗传变异，低积累镉是受主效基因控制的可遗传性状， 发掘低积累镉基因资源，培育抗镉污染的新品种是应对和防范镉污染和毒害的有效途径。甘蓝型油菜是我国最重要的油菜栽培种，是我国食用植物油的主要来源，防范或消除油菜籽生产中的镉污染对保障我国食用油安全意义极为重大。本项目拟充分利用我国油菜种质资源丰富的优势，通过大规模筛选，发掘出种子低积累镉的优异种质，运用新建立的油菜全基因组关联分析平台，鉴定控制低积累镉的关键基因，阐明甘蓝型油菜种子低积累镉的遗传、生理和分子基础，开发出可用于分子设计育种的功能基因标记。为培育耐重金属镉污染的甘蓝型油菜安全新品种提供科学指导和先进的技术手段。

项目的背景：.土壤重金属污染已成为严重威胁作物安全生产的全球性问题，我国中度、重度污染土地已达5000万亩以上，其中镉是最为普遍、毒性最严重的重金属污染物之一，过量摄入镉会导致前列腺癌等严重疾患。植物积累镉存在显著的物种间和物种内遗传变异，低积累镉是受主效基因控制的可遗传性状， 发掘低积累镉基因资源，培育抗镉污染的新品种是应对和防范镉污染和毒害的有效途径。甘蓝型油菜是我国最重要的油菜栽培种，是我国食用植物油的主要来源，防范或消除油菜籽生产中的镉污染对保障我国食用油安全意义极为重大。.主要研究内容：.1）建立高效筛选低积累重金属镉油菜优异种质的新方法。.2）筛选鉴定出一批耐镉或低积累镉的油菜优异种质资源。.3）通过全基因组关联分析，定位油菜镉积累有关的QTL区段，并鉴定耐镉（低积累镉）有关的优异单倍型。.5）鉴定了QTL区段中与甘蓝型油菜镉积累有关候选基因.重要结果、关键数据：.1）建立了一种简单快速高通量筛选低积累重金属镉油菜优异种质的新方法。.2）系统研究了镉胁迫下甘蓝型油菜萌发期胚根抑制作用以及变异规律。.3） 筛选鉴定出12份耐镉或低积累镉的油菜优异种质资源，并用于低积累镉油菜新品种选育。.4）通过全基因组关联分析，定位了油菜镉积累有关的QTL区段5个，并鉴定耐镉（低积累镉）有关的优异单倍型。.5）鉴定了QTL区段中与甘蓝型油菜镉积累有关候选基因9个。.科学意义和应用前景：.本项目充分利用我国油菜种质资源丰富的优势，通过大规模筛选，发掘出种子低积累镉的优异种质，运用新建立的油菜全基因组关联分析平台，鉴定了控制低积累镉的关键基因，开发出可用于分子设计育种的功能基因标记。本研究为培育耐重金属镉污染的甘蓝型油菜安全新品种提供科学指导和先进的技术手段。