Puccinia striiformis f. sp. tritici, the causal agent of wheat stripe (yellow) rust, is an obligate, biotrophic fungus. It was difficult to study the genetics of the pathogen due to the lack of sexual reproduction. The recent discovery of alternate hosts for P. striiformis f. sp. tritici makes it possible to study inheritance and map genes involved in its interaction with plant hosts. To identify avirulence (Avr) genes in P. striiformis f. sp. tritici, we developed a segregating population by selfing isolate 12-368 on barberry (Berberis vulgaris) plants under controlled conditions. The dikaryotic sexual population segregated for avirulent/virulent phenotypes on nine Yr single-gene lines. The parental and progeny isolates were whole-genome sequenced at >30× coverage using Illumina HiSeq PE150 technology. A total of 2,637 high-quality markers were discovered by mapping the whole-genome sequencing (WGS) reads to the reference genome of strain 93-210 and used to construct a genetic map, consisting of 41 linkage groups, spanning 7,715.0 centimorgans (cM) and covering 68 Mb of the reference genome. The recombination rate was estimated to be 1.81 ± 2.32 cM/10 kb. Quantitative trait locus analysis mapped six Avr gene loci to the genetic map, including an Avr cluster harboring four Avr genes, AvYr7, AvYr43, AvYr44, and AvYrExp2. Aligning the genetic map to the reference genome identified Avr candidates and narrowed them to a small genomic region (<200 kb). The discovery of the Avr gene cluster is useful for understanding pathogen evolution, and the identification of candidate genes is an important step toward cloning Avr genes for studying molecular mechanisms of pathogen-host interactions.

中文翻译：

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通过遗传图谱和有性种群的全基因组测序鉴定了小麦条纹锈病病原体（Puccinia striiformis f。sp。tritici）中的无毒基因簇。

小麦条锈菌f。sp。小麦，小麦条（黄色）锈的引发剂，是一种专性，活体营养真菌。由于缺乏有性生殖，很难研究病原体的遗传学。斑节对虾的替代宿主的最新发现。sp。Tritici使得研究遗传和定位与植物宿主相互作用的基因成为可能。鉴定无毒力（Avr）基因在棒状假单胞菌中。sp。小麦中，我们通过对自交分离伏牛12-368（开发的分离群体小檗）在受控条件下种植。在9个Yr单基因品系上，无核/有毒表型的双核性有性种群分离。使用Illumina HiSeq PE150技术以> 30x的覆盖率对亲本和后代分离株进行全基因组测序。通过将全基因组测序（WGS）读图映射到菌株93-210的参考基因组中，共发现了2,637个高质量标记，并用于构建遗传图谱，该图谱由41个连锁组组成，涵盖7,715.0厘摩（cM）覆盖参考基因组的68 Mb。估计重组率为1.81±2.32cM / 10kb。数量性状基因座分析将六个Avr基因位点定位到遗传图谱，包括一个带有四个Avr的Avr簇基因AvYr7，AvYr43，AvYr44和AvYrExp2。将遗传图谱与参考基因组比对可鉴定出Avr候选基因，并将它们缩小到一个小的基因组区域（<200 kb）。Avr基因簇的发现有助于理解病原体的进化，候选基因的鉴定是克隆Avr基因以研究病原体与宿主相互作用的分子机制的重要一步。