Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108, U.S.A.
Batumi Shota Rustaveli State University, Institute of Phytopathology and Biodiversity, Kobuleti, Adjara, Georgia, U.S.A.
Phytopathology. 2019 Dec;109(12):2152-2160. doi: 10.1094/PHYTO-06-19-0186-R. Epub 2019 Oct 30.
Wheat stem rust, caused by f. sp. , is a re-emerging disease exemplified by recent epidemics caused by new virulent races. Understanding the sources and origins of genetic variations in the pathogen populations globally can facilitate the development of better strategies in disease management. We analyzed 68 wheat stem rust samples collected between 2013 and 2015 from Georgia where stem rust incidences are frequent and the alternate host, common barberry, is present. A total of 116 single-pustule isolates were derived and evaluated on stem rust differential lines to determine the virulence phenotypes and 23 races were identified, many of which were detected for the first time. Unique virulence combinations including, and were detected. These virulence combinations pose new challenges to breeding programs because many of these genes are used in breeding for resistance to the Ug99 race group. Sixty-one isolates were genotyped using a custom single-nucleotide polymorphism chip and 17 genotypes were identified. The 2013 isolates contained 11 multilocus genotypes compared with isolates of 2014 and 2015, with five and three genotypes, respectively. The higher levels of virulence and genotypic diversity observed in the 2013 samples strongly indicated that sexual recombination occurs in the Georgian f. sp. population, and that the Caucasus region of Eurasia may be an important source of new races.[Formula: see text] Copyright © 2019 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
小麦秆锈病由 f. sp. 引起，是一种重新出现的疾病，其最近的流行是由新的毒力菌株引起的。了解全球病原菌群体遗传变异的来源和起源，可以促进疾病管理的更好策略的发展。我们分析了 2013 年至 2015 年间在格鲁吉亚采集的 68 个小麦秆锈病样本，该地区秆锈病发病率高，且有冬寄主小檗存在。共分离得到 116 个单疱分离物，在小麦秆锈病鉴别品种上评价其毒性表型，鉴定出 23 个小种，其中许多是首次发现。检测到独特的毒性组合，包括 、 和 。这些毒性组合给育种计划带来了新的挑战，因为这些基因中的许多被用于培育对 Ug99 菌系群的抗性。利用定制的单核苷酸多态性芯片对 61 个分离物进行基因型分析，鉴定出 17 种基因型。2013 年的分离物与 2014 年和 2015 年的分离物相比，含有 11 个多位点基因型，分别为 5 个和 3 个基因型。2013 年样本中观察到的更高水平的毒性和基因型多样性强烈表明，在格鲁吉亚小麦秆锈菌群体中发生了性重组，而欧亚大陆的高加索地区可能是新菌系的重要来源。[公式：见正文]版权所有 2019 作者。这是一个开放获取的文章，分布在 CC BY 4.0 国际许可证下。
