大豆抗胞囊线虫病新位点SCNR7相关基因的克隆和功能分析

Soybean cyst nematode (SCN) is a highly destructive pathogen in soybean production. SCN race 1 and race 2 are predominant races in Huang-Huai Valleys. A new QTL SCNR7 resistant to SCN race 1 was detected in an F2 population by BSA analysis and the same QTL resistant to both race 1 and race 2 was also detected in RIL2:8 population. The QTL could explain up to 71% and 58% of the resistance phenotypic variation for race 1 and race 2 in RIL2:8 population, respectively. It is an important QTL for combating SCN. In this study, the SCNR7 gene expression analysis will be performed with real-time fluorescence quantitative PCR technology. The function of candidate genes will be verified by hairy root transformation using Agrobacterium rhizogenes. In addition, haplotypes and alleles highly associated with SCN resistance based on the germplasm will be determined, functional markers will be developed for screening SCN resistance genes and for the transferring the gens to elite soybean in breeding programs. The research and utilization of SCNR7 will broaden the genetic basis for SCN breeding and provide a scientific basis for the molecular marker assisted breeding of soybean cyst nematode.

大豆胞囊线虫病严重危害大豆生产，1号小种和2号小种是黄淮海优势小种。项目申请人通过F2群体BSA分析检测到一个抗1号小种的新QTL SCNR7，在RIL2:8群体中也检测到抗1号和2号小种的同一个QTL SCNR7，RIL2:8群体中SCNR7对1号小种和2号小种的抗性表型变异解释率分别达到70%和58%。本研究将在此基础上，继续对候选基因区段进行序列分析，拟通过荧光定量RT-PCR技术筛选与胞囊线虫抗性相关的候选基因，以发根农杆菌介导的遗传转化方法，确认目的基因并分析其在抗大豆胞囊线虫中的功能，初步解析SCNR7调控邯6192抗大豆胞囊线虫的分子机制。同时通过大豆种质资源目的基因位点的单倍型分析，鉴定该基因位点的优良等位基因并开发功能标记应用于大豆的抗胞囊线虫育种。SCNR7位点的研究和利用将拓宽大豆抗胞囊线虫育种的遗传基础，为大豆抗胞囊线虫分子标记辅助育种提供依据。

大豆胞囊线虫是危害大豆生产非常严重的一种世界性害虫。目前，黄淮海流域大豆胞囊线虫的优势生理小种由1号生理小种演化为2号生理小种，培育抗病品种是降低其危害最有效的解决途径。邯6192是农艺性状优异的抗性大豆品种，我们检测到一个调控邯6192抗大豆胞囊线虫1号和2号生理小种的新抗性位点SCNR7。根据SCNR7在基因组上的区间和抗感品种（邯6192vs.郑9525）接种前后的转录组数据分析，筛选出6个差异表达的候选基因。通过分析候选基因的功能注释和接种前后其表达水平的变化，初步确定Glyma.07G139800为抗大豆胞囊线虫基因，进一步利用荧光定量RT-PCR技术进行对其进行了初步验证。编码区序列分析表明邯6192在Glyma.07G139800的第二个外显子上有1处碱基差异造成了氨基酸的变化，针对此处差异开发了1个KASP标记，可用于抗性品种的鉴定。通过农杆菌介导的遗传转化方法获得了大豆胞囊线虫抗性基因过量表达和RNAi的大豆植株。SCNR7位点的研究和利用将拓宽大豆抗胞囊线虫育种的遗传基础，为大豆抗胞囊线虫分子标记辅助育种提供依据。以邯6192为抗性亲本创制了2份优异大豆新种质，均抗大豆胞囊线虫1号、中抗2号生理小种且抗拟茎点种腐病，新种质为大豆抗胞囊线虫育种提供抗源。