Rouxel Mélanie, Mestre Pere, Baudoin Anton, Carisse Odile, Delière Laurent, Ellis Michael A, Gadoury David, Lu Jiang, Nita Mizuho, Richard-Cervera Sylvie, Schilder Annemiek, Wise Alice, Delmotte François
Phytopathology. 2014 Jul;104(7):692-701. doi: 10.1094/PHYTO-08-13-0225-R.
The putative center of origin of Plasmopara viticola, the causal agent of grape downy mildew, is eastern North America, where it has been described on several members of the family Vitaceae (e.g., Vitis spp., Parthenocissus spp., and Ampelopsis spp.). We have completed the first large-scale sampling of P. viticola isolates across a range of wild and cultivated host species distributed throughout the above region. Sequencing results of four partial genes indicated the presence of a new P. viticola species on Vitis vulpina in Virginia, adding to the four cryptic species of P. viticola recently recorded. The phylogenetic analysis also indicated that the P. viticola species found on Parthenocissus quinquefolia in North America is identical to Plasmopara muralis in Europe. The geographic distribution and host range of five pathogen species was determined through analysis of the internal transcribed spacer polymorphism of 896 isolates of P. viticola. Among three P. viticola species found on cultivated grape, one was restricted to Vitis interspecific hybrids within the northern part of eastern North America. A second species was recovered from V. vinifera and V. labrusca, and was distributed across most of the sampled region. A third species, although less abundant, was distributed across a larger geographical range, including the southern part of eastern North America. P. viticola clade aestivalis predominated (83% of isolates) in vineyards of the European winegrape V. vinifera within the sampled area, indicating that a single pathogen species may represent the primary threat to the European host species within eastern North America.
葡萄霜霉病的病原菌葡萄生单轴霉的假定起源中心是北美东部，在那里它已在葡萄科的几个成员上被描述（例如葡萄属、爬山虎属和蛇葡萄属）。我们已完成了对分布于上述区域的一系列野生和栽培寄主物种上的葡萄生单轴霉分离株的首次大规模采样。四个部分基因的测序结果表明，在弗吉尼亚州的狐葡萄上存在一种新的葡萄生单轴霉物种，这是最近记录的葡萄生单轴霉的四个隐性物种之外的新物种。系统发育分析还表明，在北美五叶地锦上发现的葡萄生单轴霉物种与欧洲的壁生单轴霉相同。通过对896个葡萄生单轴霉分离株的内部转录间隔区多态性分析，确定了五种病原菌物种的地理分布和寄主范围。在栽培葡萄上发现的三种葡萄生单轴霉物种中，一种局限于北美东部北部的葡萄种间杂种。第二种物种从欧亚葡萄和美洲葡萄中分离得到，分布于大部分采样区域。第三种物种虽然数量较少，但分布在更大的地理范围内，包括北美东部南部。在采样区域内，欧洲酿酒葡萄欧亚葡萄的葡萄园里，葡萄生单轴霉estivalis分支占主导地位（占分离株的83%），这表明单一病原菌物种可能是北美东部欧洲寄主物种面临的主要威胁。
