Quesada-Ocampo L M, Granke L L, Olsen J, Gutting H C, Runge F, Thines M, Lebeda A, Hausbeck M K
Visiting Research Associate.
Undergraduate Research Assistant.
Plant Dis. 2012 Oct;96(10):1459-1470. doi: 10.1094/PDIS-11-11-0943-RE.
Pseudoperonospora cubensis is a destructive foliar pathogen of economically important cucurbitaceous crops in the United States and worldwide. In this study, we investigated the genetic structure of 465 P. cubensis isolates from three continents, 13 countries, 19 states of the United States, and five host species using five nuclear and two mitochondrial loci. Bayesian clustering resolved six genetic clusters and suggested some population structure by geographic origin and host, because some clusters occurred more or less frequently in particular categories. All of the genetic clusters were present in the sampling from North America and Europe. Differences in cluster occurrence were observed by country and state. Isolates from cucumber had different cluster composition and lower genetic diversity than isolates from other cucurbits. Because genetic structuring was detected, isolates that represent the genetic variation in P. cubensis should be used when developing diagnostic tools, fungicides, and resistant host varieties. Although this study provides an initial map of global population structure of P. cubensis, future genotyping of isolates could reveal population structure within specific geographic regions, across a wider range of hosts, or during different time points during the growing season.
古巴假霜霉是美国乃至全球经济上重要的葫芦科作物的一种毁灭性叶部病原菌。在本研究中，我们利用五个核基因座和两个线粒体基因座，对来自三大洲、13个国家、美国19个州以及五个寄主物种的465株古巴假霜霉分离株的遗传结构进行了研究。贝叶斯聚类解析出六个遗传簇，并表明存在一些按地理来源和寄主划分的种群结构，因为某些簇在特定类别中出现的频率或多或少有所不同。所有遗传簇都存在于来自北美和欧洲的样本中。按国家和州观察到簇出现情况的差异。黄瓜上的分离株与其他葫芦科作物上的分离株相比，具有不同的簇组成且遗传多样性较低。由于检测到了遗传结构，在开发诊断工具、杀菌剂和抗性寄主品种时，应使用代表古巴假霜霉遗传变异的分离株。尽管本研究提供了古巴假霜霉全球种群结构的初步图谱，但未来对分离株的基因分型可能会揭示特定地理区域内、更广泛寄主范围内或生长季节不同时间点的种群结构。
