Abstract：
Barley stripe rust is a relatively new disease in the United States. The pathogen, Puccinia striiformis f. sp. hordei (Psh), was first observed in Texas in 1991 and has spread north and westwards and mainly caused epidemics in the western United States. A total of 447 isolates collected from 1993 to 2017 were identified as 382 multilocus genotypes (MLGs) using 14 simple sequence repeat markers. The MLGs were clustered into six molecular groups (MGs) using the discriminant analysis of principal components and the hierarchical cluster analysis, and the MGs had significant differences in frequency in different years. MG1 was present in the population prior to the year 2000. MG2, MG3, and MG4 became predominate after 2000. MG5 was detected in all 24 years but more frequent from 2010 to 2017. MG6 was the most recent group detected mainly from 2011 to 2017 and had the highest correlation coefficient with the virulence phenotypes among the MGs. The heterozygosity and genotypic diversity of the Psh populations increased from 2000 to 2017, even more from 2010 to 2017. The results indicate rapid genetic changes from year to year, with major molecular group changes around 2000 and 2010. The possible mechanisms underlying the population changes are discussed.
摘要：
大麦条锈病在美国是一种相对较新的疾病。病原体,条锈病f.sp.hordei(Psh),1991年在德克萨斯州首次观察到，并向北和向西传播，主要在美国西部引起流行病。从1993年至2017年收集的447个分离株被鉴定为382个多基因座基因型（MLG），使用14个简单序列重复标记。利用主成分判别分析和层次聚类分析将MLGs分为6个分子群(MGs),不同年份的MGs频率存在显著差异。MG1在2000年之前存在于人群中。MG2、MG3和MG4在2000年后成为主导。MG5在所有24年内都被检测到，但从2010年到2017年更频繁。MG6是主要从2011年至2017年检测到的最新组，并且与MGs中的毒力表型具有最高的相关系数。从2000年到2017年，Psh种群的杂合性和基因型多样性有所增加，从2010年到2017年甚至更高。结果表明，每年都有快速的遗传变化，主要分子群体在2000年和2010年左右发生变化。讨论了人口变化的可能机制。
