Genome-Wide Association Mapping for Resistance to Leaf and Stripe Rust in Winter-Habit Hexaploid Wheat Landraces

Leaf rust, caused by Puccinia triticina (Pt), and stripe rust, caused by P. striiformis f. sp. tritici (Pst), are destructive foliar diseases of wheat worldwide. Breeding for disease resistance is the preferred strategy of managing both diseases. The continued emergence of new races of Pt and Pst requires a constant search for new sources of resistance. Here we report a genome-wide association analysis of 567 winter wheat (Triticum aestivum) landrace accessions using the Infinium iSelect 9K wheat SNP array to identify loci associated with seedling resistance to five races of Pt (MDCL, MFPS, THBL, TDBG, and TBDJ) and one race of Pst (PSTv-37) frequently found in the Northern Great Plains of the United States. Mixed linear models identified 65 and eight significant markers associated with leaf rust and stripe rust, respectively. Further, we identified 31 and three QTL associated with resistance to Pt and Pst, respectively. Eleven QTL, identified on chromosomes 3A, 4A, 5A, and 6D, are previously unknown for leaf rust resistance in T. aestivum.由小麦叶锈菌（Puccinia triticina, Pt）和条形柄锈菌小麦专化型（Puccinia striiformis f. sp. tritici, Pst）分别引发的叶锈病与条锈病，是全球范围内危害小麦的毁灭性叶部病害。培育抗病品种是防控这两类病害的首选策略。鉴于Pt与Pst不断涌现新的生理小种，亟需持续挖掘新的抗病种质资源。 本研究针对567份普通小麦（Triticum aestivum）地方种质资源，采用Infinium iSelect 9K小麦单核苷酸多态性（Single Nucleotide Polymorphism, SNP）芯片开展全基因组关联分析，旨在鉴定与苗期抗性相关的遗传位点，所涉抗性针对美国北部大平原地区流行的5个Pt生理小种（MDCL、MFPS、THBL、TDBG、TBDJ）以及1个Pst生理小种（PSTv-37）。 通过混合线性模型分析，本研究分别筛选得到65个与叶锈病抗性相关的显著分子标记，以及8个与条锈病抗性相关的显著分子标记。进一步分析共鉴定到31个与Pt抗性相关的数量性状位点（Quantitative Trait Locus, QTL），以及3个与Pst抗性相关的QTL。其中，定位在3A、4A、5A及6D染色体上的11个QTL，为目前普通小麦中首次报道的叶锈病抗性位点。