结合关联分析与转录组测序发掘野生二粒小麦条锈病抗性基因

Wheat stripe rust, caused by the fungal pathogen Puccinia striiformis sp. tritici (Pst), is one of the most devastating diseases to wheat all over the world. Breeding resistant cultivars is the basic solution for controlling the stripe-rust disease. Wild emmer wheat (Triticum dicoccoides), as the progenitors of cultivated wheat, possesses elite alleles, and is a valuable genetic resources for wheat breeding. Discovering key genes and loci related to stripe rust resistance from wild emmer wheat can provide important molecular elements for breeding resistant cultivars, and thus it has important scientific significance. In previous study, we have tested stripe rust challenge on 350 wild emmer wheat accessions and constructed phenotypic database for stripe rust resistance. On this basis, the project will adopt association mapping method to detect new loci significantly associated with stripe rust resistance using genomic-wide SNP markers. Furthermore, chromosome interval determining stripe rust resistance will be obtained based on the mapped QTL and linked SNP. Stripe rust responsive genes will be revealed in stripe rust resistant and sensitive accession using RNA-seq technology. Importantly, the putative key genes induced by stripe rust and located the chromosome interval will be discovered. The VIGS technology will be employed to identify the gene function. The study will provide important molecular elements for breeding new cultivar resistant to stripe rust.

条锈病是世界范围内严重影响小麦生产的真菌性病害，培育抗条锈新品种是解决这一问题的根本途径。野生二粒小麦是现代栽培小麦的直接祖先，蕴藏着各类优异基因资源，是小麦遗传改良极其珍贵的种质资源库。从野生二粒小麦中发掘优异抗条锈病基因是科学利用抗条锈资源及培育小麦抗条锈品种的重要基础。本项目前期已完成对350份野生二粒小麦种质条锈病抗性评价及表型数据库的构建。在此基础上，利用覆盖全基因组的多态性SNPs标记对350份野生二粒小麦种质进行基因型标定；基于关联分析策略发掘抗条锈病新基因位点，并整合已定位的抗条锈病QTL进一步确定控制条锈病的染色体区间；以极端抗条锈病和敏感种质为材料，基于RNA-Seq技术鉴定位于上述染色体区间内受条锈病显著诱导的基因，作为条锈病应答的候选关键基因；基于VIGS技术解析候选基因的功能。项目实施将为培育抗锈病小麦新品种提供重要分子元件，具有重要的科学意义。

发掘抗条锈病基因或功能元件是培育小麦抗条锈病品种的物质基础。野生二粒小麦蕴藏着多种现代农作物所急需的各类基因资源，是小麦改良极其珍贵的种质资源库。本项目对500余份野生二粒小麦在四川和德州进行了多年多点的条锈病的抗性鉴定，建立了野生二粒小麦条锈病表型数据库，筛选出40余份对条锈病完全免疫的种质，为开展抗病基因定位、抗性基因挖掘以及抗病新品种的培育奠定了重要的材料基础。基于多组学数据结合关联分析策略发掘到与条锈病抗性性状相关联的多个染色体区间，鉴定筛选出一批参与野生二粒小麦条锈病应答的基因、转录因子和LncRNA；并利用RACE技术克隆了3个优异的条锈病应答的候选基因，现在正在利用超表达和VIGS手段对这些功能元件进行条锈病抗病功能验证。以上工作解析了野生二粒小麦应答条锈病的分子机制，为将来培育条锈病抗病品种提供了重要科学依据。经过三年探索，已发表SCI论文3篇，申请的1项专利已经进入实质审查阶段，另有2篇学术论文在审稿中，1篇论文在准备中。总之，我们完成了项目的各项研究目标。