Resistance to wheat spike blast (WSB), caused by the Magnaporthe oryzae triticum pathotype (MoT), has relied upon a single major source: the 2N^vS translocation introgressed from the wild relative Aegilops ventricosa Tausch. However, this resistance is partial and recently partially overcome by newer MoT races. To characterize potential novel loci conferring resistance to WSB, we conducted a genome‐wide association study (GWAS) using a diverse panel of 384 wheat genotypes phenotyped under three controlled‐environment conditions using MoT isolates T‐25 (301 genotypes), B‐71 (87 genotypes), and 008 (49 genotypes). Genotyping‐by‐sequencing identified 13,175 single nucleotide polymorphisms (SNPs) after filtering. Principal components analysis (PCA) identified two clusters based on the presence or absence of the 2N^vS translocation, and the first three PCAs explained 13% of the genetic variation. Three individual analyses were performed (full [all genotypes combined], 2N^vS genotypes only, and non‐2N^vS genotypes only) using a linear mixed model and a threshold of significance of false discovery rate at 5%. Association analysis detected 25 significant SNPs for the full GWAS with isolate T‐25, in which 21 were mapped on chromosome 2A in the same physical position as the 2N^vS translocation. Highly significant linkage disequilibrium among these SNPs suggested they might tag the same quantitative trait locus (QTL). No significant associations were identified with isolates B‐71 and 008, likely due to the small sample size. A QTL pyramiding analysis showed that the combination of multiple QTL was not statistically different from the individual effect of the 2A QTL. Further validation of these genomic regions can aid breeding for broad spectrum and durable WSB resistance.

中文翻译：

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全基因组关联揭示了将1B和1D基因座与2NvS易位金字塔化用于小麦瘟病控制的有限益处

由小麦单胞菌小麦致病型（MoT）引起的对小麦穗瘟（WSB）的抗药性依赖于一个主要来源：从野生亲缘Aegilops ventricosa渗入的2N ^v S易位陶施。但是，这种阻力是部分的，而最近的MoT竞赛则部分地克服了。为了表征潜在的赋予WSB抗性的新基因座，我们进行了全基因组关联研究（GWAS），使用了MoT分离株T-25（301基因型），B-71的384种小麦基因型在三种受控环境下的表型。 （87个基因型）和008（49个基因型）。通过测序进行基因分型后，筛选出13,175个单核苷酸多态性（SNP）。主成分分析（PCA）根据2N ^vs S易位的存在确定了两个簇，前三个PCA解释了13％的遗传变异。进行了三个单独的分析（完整[所有基因型合并]，仅2N ^v S基因型和非2N基因型）仅使用^v S基因型），使用线性混合模型，错误发现率的显着性阈值为5％。关联分析检测到带有隔离株T-25的完整GWAS的25个重要SNP，其中21个位于2A染色体上的位置与2N ^v S易位相同。这些SNP之间高度显着的连锁不平衡表明它们可能标记了相同的数量性状基因座（QTL）。没有发现与分离株B-71和008的显着相关性，这可能是由于样本量小所致。QTL金字塔分析表明，多个QTL的组合与2A QTL的个体作用在统计学上没有差异。这些基因组区域的进一步验证可有助于广谱和持久的WSB抗性育种。