Canadian Journal of Plant Pathology ( IF 2 ) Pub Date : 2021-06-08 , DOI: 10.1080/07060661.2020.1870002 Bohan Wei 1, 2 , Therese Despins 1 , Myriam R. Fernandez 3 , Stephen E. Strelkov 2 , Yuefeng Ruan 3 , Robert Graf 1 , Reem Aboukhaddour 1
Abstract
Tan spot is a destructive disease of wheat caused by the fungus Pyrenophora tritici-repentis (Ptr), with most fungal isolates in Canada known to produce the necrotrophic effector (NE) ToxA. In this study, 144 Ptr isolates collected from durum, winter bread wheat, and grasses in western Canada were evaluated for race classification on a host differential set. The susceptibility of 114 durum and winter bread wheat genotypes to Ptr races 2 (R2), 3 (R3), and 5 (R5), producing the NEs ToxA, ToxB, and ToxC, respectively, was evaluated in bioassays. The host genotypes were tested for the presence of Tsn1, the ToxA-sensitivity gene, by PCR analysis. Race composition varied based on the host type and ploidy level from which the isolates were recovered. R1 (ToxA and ToxC-producer) and R2 were predominant on wheat and occurred in equal frequency on durum, while R1 occurred twice as frequently as R2 on winter bread wheat. R3 was recovered only from durum wheat, and the non-pathogenic R4 was the only race recovered from grasses. Susceptibility to R2 and R3 was more common in Canadian than in European wheat, while susceptibility to R5 was more common in durum and European wheat. Tsn1 amplified at a higher percentage in Canadian (51.2% in winter bread, 59.0% in durum) vs. European (20.5%) wheat genotypes. The presence of Tsn1, however, did not result in susceptibility to ToxA-producing isolates in 35.9% of durum genotypes, indicating that other factors are involved in the Ptr-durum interaction and that ToxA-Tsn1 may not play a significant role in tetraploid wheat.
中文翻译:
Pyrenophora tritici-repentis 种属分布与硬粒小麦和冬面包小麦倍性水平和易感性的关系
摘要
棕褐色斑是由真菌Pyrenophora tritici-repentis ( Ptr )引起的小麦破坏性病害,已知加拿大的大多数真菌分离株会产生坏死性效应子 (NE) ToxA。在这项研究中,从加拿大西部的硬粒小麦、冬面包小麦和禾本科植物中收集的144 个Ptr分离株在宿主差异集上进行了种族分类评估。在生物测定中评估了 114 种硬粒小麦和冬面包小麦基因型对Ptr 小种2 (R2)、3 (R3) 和 5 (R5) 的敏感性,分别产生 NEs ToxA、ToxB 和 ToxC。检测宿主基因型是否存在Tsn1,ToxA 敏感性基因,通过 PCR 分析。种族组成因宿主类型和分离株的倍性水平而异。R1(ToxA 和 ToxC 生产者)和 R2 在小麦上占主导地位,并且在硬粒小麦上的发生频率相同,而 R1 在冬面包小麦上的发生频率是 R2 的两倍。R3 仅从硬粒小麦中回收,非致病性 R4 是唯一从草中回收的小种。加拿大小麦对 R2 和 R3 的敏感性比欧洲小麦更常见,而对 R5 的敏感性在硬粒小麦和欧洲小麦中更常见。与欧洲 (20.5%) 小麦基因型相比,Tsn1在加拿大(冬季面包中为 51.2%,硬粒小麦中为 59.0%)的扩增百分比更高。Tsn1的存在然而,没有造成易感性硬粒基因型的35.9%的ToxA生产菌株,这表明其他因素参与PTR -durum互动和ToxA- TSN1可能无法播放四倍体小麦显著的作用。