Plant Breeding Institute, University of Sydney, Cobbitty, Narellan, New South Wales 2567, Australia.
Phytopathology. 2021 Apr;111(4):684-694. doi: 10.1094/PHYTO-05-20-0193-R. Epub 2021 Mar 5.
Barley is an intermediate or near nonhost to many cereal rust pathogens that infect grasses, making it a highly suitable model to understand the evolution and genetic basis of nonhost resistance (NHR) in plants. To characterize the genetic architecture of NHR in barley, we used the Oregon Wolfe Barley doubled haploid and Morex × SusPtrit recombinant inbred line mapping populations. To elicit a wide array of NHR responses, we tested 492 barley accessions and both mapping populations with pathogenically diverse cereal rust isolates representing distinct formae speciales adapted to , , , and spp.: f. sp. (oat crown rust pathogen) and f. sp. (ryegrass crown rust pathogen), f. sp. (oat stem rust pathogen) and f. sp. (the ryegrass stem rust pathogen), and f. sp. (wheat stripe rust pathogen) and f. sp. (barley grass stripe rust pathogen). With the exception of f. sp. and f. sp. , susceptibility and segregation for NHR was observed in the barley accessions and both mapping populations. Quantitative trait loci (QTLs) for NHR were mapped on all seven chromosomes. NHR in barley to the heterologous rusts tested was attributable to a combination of QTLs with either or both overlapping and distinct specificities. Across both mapping populations, broadly effective NHR loci were also identified that likely play a role in host specialization.
大麦是许多感染禾本科植物的谷物锈病病原体的中间或近非寄主，使其成为理解植物非寄主抗性（NHR）进化和遗传基础的高度合适模型。为了表征大麦 NHR 的遗传结构，我们使用了俄勒冈沃尔夫大麦加倍单倍体和 Morex×SusPtrit 重组自交系作图群体。为了引发广泛的 NHR 反应，我们用致病性不同的谷物锈菌分离株测试了 492 个大麦品种和两个作图群体，这些分离株代表了适应于 、 、 和 spp.的不同专化形式： f. sp. （燕麦冠锈病病原体）和 f. sp. （黑麦冠锈病病原体）， f. sp. （燕麦秆锈病病原体）和 f. sp. （黑麦秆锈病病原体），以及 f. sp. （小麦条锈病病原体）和 f. sp. （大麦草条锈病病原体）。除了 f. sp. 和 f. sp. 之外，大麦品种和两个作图群体中均观察到对 NHR 的敏感性和分离。在所有 7 条染色体上都定位了 NHR 的数量性状基因座（QTL）。大麦对测试的异源锈病的 NHR 归因于具有重叠和不同特异性的 QTL 的组合。在两个作图群体中，还鉴定出了广泛有效的 NHR 基因座，它们可能在宿主专化中起作用。
