基于代谢组的关联分析发掘油菜菌核病抗性相关基因资源

Brassica napus is an worldwide important oil crop. Sclerotinia stem rot (SSR) caused by the fungal pathogen Sclerotinia sclerotiorum is one of the most devastating diseases worldwide and seriously affects the yield and quality of rapeseed. The resistance to S. sclerotiorum in B. napus is a quantitative trait and controlled by minor multiple quantitative trait loci (QTLs). But all the QTLs identified for S. sclerotiorum resistance only explained a small portion of the phenotypic variation, and it is still difficult to distinguish the candidate genes in these QTLs. Metabolome-based genome-wide association study (mGWAS) has displayed superiority in identification of functional genes and in understanding plant metabolic pathways. Combining these advantages with our previous work, 420 accessions of B. napus from all over the world were genotyped by re-sequencing. The phenotype data of resistance to SSR and the variations of metabolites from leaves inoculated with and without the pathogen will be collected and analyzed by GWAS and mGWAS, respectively. The common candidate genes highlighted and mapped to defense metabolites pathway will be identified, and the function of them will be verified by molecular biology experiment. The implementation of this project will reveal the genetic basis and effective metabolites for quantitative resistance in plant defense, which will promote the breeding for enhancing resistance against S. sclerotiorum.

油菜是我国主要油料作物之一，真菌核盘菌引起的菌核病是其主要病害，严重影响着油菜生产。油菜菌核病抗性为多基因控制数量性状，尚未发现免疫或高抗的资源，发掘有效的抗性相关基因和育种材料，培育抗病品种是控制该病的主要措施。植物代谢物在抗病中发挥着重要作用，而近年来基于代谢组的关联分析(mGWAS)在功能基因鉴定和相关遗传机制研究中显示出巨大的优势，如mGWAS位点效应高、可快速筛选候选基因等。本项目拟鉴定已完成全基因组重测序的420份油菜种质资源的菌核病抗性，检测接种核盘菌前、后的代谢物含量，然后通过抗病GWAS和mGWAS分析获得各自关联位点，进一步通过二者的对比分析寻找与抗病性和与代谢物共关联的位点，从而获得抗病相关后候选基因及对应的代谢物，再用适当方法进行候选基因的功能验证。本项目预期结果将为发掘植物数量抗病性基因资源提供借鉴，有助于进一步阐述植株代谢物在菌核病抗病性中的作用及其机制。

油菜是全世界重要的油料作物之一，真菌核盘菌引起的菌核病是其生产上的主要病害。油菜菌核病抗性为多基因控制数量性状，尚未发现免疫或高抗的资源，发掘有效的抗性相关基因和育种材料，培育抗病品种是控制该病的最经济和科学的措施。本研究利用代谢组的关联分析(mGWAS)在功能基因鉴定和相关遗传机制研究中的优势，基于全基因组重测序的420份油菜种质资源的菌核病抗性，检测接种核盘菌前、后的610种代谢物含量，通过抗病GWAS和mGWAS联合分析获得7个抗病性和代谢物含量共关联的位点，进一步挖掘抗病相关候选基因及对应的抗病代谢物鉴定到调控十字花科特有的抗病代谢物硫代葡萄糖苷的合成基因BnaA09.MYB28和转运基因BnaA06.GTR2，并借助CRISPR/Cas9技术创制了叶片高硫苷（抗病）且种子低硫苷（高品质）的油菜育种材料。本项目研究为培育油菜高抗、优质品种提供了优异的种质资源，且方法和结果为阐述作物代谢物在抗病性中的作用和机制提供了方法策略。