Table_4_Identification of new resistance loci against wheat sharp eyespot through genome-wide association study.xlsx

IntroductionWheat sharp eyespot caused by Rhizoctonia cerealis is a serious pathogenic disease affecting plants. The effective strategy for controlling this disease is breeding resistant cultivar. However, to date, no wheat varieties are fully resistant to sharp eyespot, and only a few quantitative trait loci (QTLs) have been shown to be associated with sharp eyespot resistance.
MethodsTo understand the genetic basis of this disease, a genome-wide association study (GWAS) of sharp eyespot resistance in 262 varieties from all China wheat regions was conducted.
ResultsAfter cultivation for three years, only 6.5% of the varieties were resistant to sharp eyespot. Notably, the varieties from the middle and lower Yangtze River displayed higher sharp eyespot resistance than those from Huanghuai wheat zone. Only two varieties had the same resistance level to the control Shanhongmai. The results of GWAS showed that 5 single nucleotide polymorphism (SNP) loci were markedly related to sharp eyespot resistance in the three years repeatedly, and two QTLs, qSE-6A and qSE-7B, on chromosome 6A and 7B were identified. Based on the ‘CG’ haplotypes of significant SNPs, we found that the two QTLs exhibited additive effects on attenuating sharp eyespot resistance.
DiscussionThese results provide novel insights into the genetic basis of sharp eyespot resistance in China wheat varieties. The SNPs related to sharp eyespot resistance can be applied for marker-assisted selection in plant breeding.

引言
由禾谷丝核菌（Rhizoctonia cerealis）引发的小麦纹枯病是一种危害严重的植物病原性病害。防控该病害的有效策略为培育抗病品种。然而截至目前，尚无小麦品种对纹枯病表现为完全抗病，且仅有少量数量性状位点（quantitative trait loci, QTLs）被证实与纹枯病抗病性相关。
材料与方法
为解析该病害的遗传基础，本研究针对覆盖全国各小麦主产区的262份小麦品种，开展了小麦纹枯病抗病性的全基因组关联分析（GWAS）。
结果
经过连续三年的种植鉴定，仅有6.5%的供试品种表现出纹枯病抗病性。值得注意的是，长江中下游麦区的品种较黄淮麦区品种展现出更高的纹枯病抗病水平。仅有两份品种的抗病级别与对照品种山红麦（Shanhongmai）一致。全基因组关联分析结果显示，在三年鉴定中均稳定检测到5个与纹枯病抗病性显著相关的单核苷酸多态性（SNP）位点，并在6A和7B染色体上分别鉴定到两个QTL：qSE-6A与qSE-7B。基于显著SNP的‘CG’单倍型分析结果表明，这两个QTL可通过加性效应减弱小麦对纹枯病的感病性，进而提升植株的抗病能力。
讨论
本研究结果为解析我国小麦品种纹枯病抗病性的遗传基础提供了全新的研究视角。与纹枯病抗病性相关的SNP位点可应用于作物育种中的标记辅助选择环节。