Data from: Phylogenetic and population genetic analyses of Phaeosphaeria nodorum and its close relatives indicate cryptic species and an origin in the Fertile Crescent

The origin of the fungal wheat pathogen Phaeosphaeria nodorum remains unclear despite earlier intensive global population genetic and phylogeographical studies. We sequenced 1,683 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.尽管此前已开展过深入的全球群体遗传学与系统地理学研究，小麦格孢腔菌（Phaeosphaeria nodorum）——一种小麦真菌病原菌——的起源仍未明确。我们对全球分布的355株格孢腔菌属（Phaeosphaeria）菌株的3个基因座上的1683个碱基对（base pair, bp）进行了测序，其中包含74株采自伊朗小麦起源中心附近区域的菌株。我们共鉴定出9个系统发育独立的进化枝，其中包括2个此前未被发现的物种，暂命名为P1和P2，均采集自伊朗地区。溯祖分析（coalescent analysis）结果显示，P1和P2是P. nodorum以及本研究中鉴定的其他格孢腔菌属物种的姊妹种。两个物种，即P. nodorum与燕麦壳孢菌小麦专化型1号（P. avenaria f. sp. tritici 1，简称Pat1），约占所采样菌株总数的85%，是该物种复合体中占主导地位的小麦侵染性病原菌。我们设计了聚合酶链式反应-限制性片段长度多态性（PCR-RFLP）检测方法，用于区分P. nodorum与Pat1。约4%的P. nodorum和Pat1菌株存在杂交现象的分子证据。对简单序列重复（Simple Sequence Repeat, SSR）位点及序列位点的私有等位基因丰富度的测算结果表明，P. nodorum的起源中心与其寄主的分布范围重合于新月沃地（Fertile Crescent）。我们推测该物种复合体的起源同样位于新月沃地，9个物种中有4个仅在伊朗采集的菌株样本中被发现。