Plant Pathology Group, Institute of Integrative Biology, ETH Zurich, CH-8092 Zürich, Switzerland.
Fungal Genet Biol. 2012 Nov;49(11):882-95. doi: 10.1016/j.fgb.2012.08.001. Epub 2012 Aug 24.
The origin of the fungal wheat pathogen Phaeosphaeria nodorum remains unclear despite earlier intensive global population genetic and phylogeographical studies. We sequenced 1683 bp distributed across three loci in 355 globally distributed Phaeosphaeria isolates, including 74 collected in Iran near the center of origin of wheat. We identified nine phylogenetically distinct clades, including two previously unknown species tentatively named P1 and P2 collected in Iran. Coalescent analysis indicates that P1 and P2 are sister species of P. nodorum and the other Phaeosphaeria species identified in our analysis. Two species, P. nodorum and P. avenaria f. sp. tritici 1 (Pat1), comprised ~85% of the sampled isolates, making them the dominant wheat-infecting pathogens within the species complex. We designed a PCR-RFLP assay to distinguish P. nodorum from Pat1. Approximately 4% of P. nodorum and Pat1 isolates showed evidence of hybridization. Measures of private allelic richness at SSR and sequence loci suggest that the center of origin of P. nodorum coincides with its host in the Fertile Crescent. We hypothesize that the origin of this species complex is also in the Fertile Crescent, with four species out of nine found exclusively in the Iranian collections.
尽管先前进行了全球范围内的种群遗传和系统地理学研究，但真菌性小麦病原菌禾谷平脐蠕孢（Phaeosphaeria nodorum）的起源仍不清楚。我们对 355 个全球分布的禾谷平脐蠕孢分离株中的 355 个进行了三个基因座 1683bp 的测序，包括在小麦起源中心附近的伊朗采集的 74 个。我们确定了 9 个系统发育上不同的分支，包括在伊朗采集的两个暂命名为 P1 和 P2 的未知物种。系统发育分析表明，P1 和 P2 是禾谷平脐蠕孢及其它在我们的分析中鉴定出的平脐蠕孢物种的姊妹种。两个物种，禾谷平脐蠕孢和禾本科颖壳蠕孢（P. avenaria f. sp. tritici 1，Pat1）约占采样分离株的 85%，使其成为该物种复合体中感染小麦的主要病原菌。我们设计了一个 PCR-RFLP 检测法来区分禾谷平脐蠕孢和 Pat1。约 4%的禾谷平脐蠕孢和 Pat1 分离株显示出杂交的证据。SSR 和序列位点的私有等位基因丰富度的衡量标准表明，禾谷平脐蠕孢的起源与其在新月沃地的宿主相同。我们假设该物种复合体的起源也在新月沃地，在九个物种中，有四个仅在伊朗的采集样本中发现。
