Data from: Co-occurrence and hybridization of anther-smut pathogens specialized on Dianthus hosts

Host specialization has important consequences for the diversification and ecological interactions of obligate pathogens. The anther-smut disease of natural plant populations, caused by Microbotryum fungi, has been characterized by specialized host-pathogen interactions, which contribute in part to the isolation among these numerous fungal species. This study investigated the molecular variation of Microbotryum pathogens within the geographic and host-specific distributions on wild Dianthus species in southern European Alps. In contrast to prior studies on this pathogen genus, a range of overlapping host specificities was observed for four delineated Microbotryum lineages on Dianthus hosts, and their frequent co-occurrence within single-host populations was quantified at local and regional scales. In addition to potential consequences for direct pathogen competition, the sympatry of Microbotryum lineages led to hybridization between them in many populations, and these admixed genotypes suffered significant meiotic sterility. Therefore, this investigation of the anther-smut fungi reveals how variation in the degrees of host specificity can have major implications for ecological interactions and genetic integrity of differentiated pathogen lineages.宿主特化（Host specialization）对专性病原菌（obligate pathogens）的物种多样化与生态互作模式具有重要影响。由黑粉菌属（Microbotryum）真菌引发的野生植物种群花药黑粉病（anther-smut disease），其典型特征为特化的宿主-病原菌互作关系，这类互作在一定程度上促成了该类群众多真菌物种间的生殖隔离。本研究聚焦分布于南阿尔卑斯山区的野生石竹属（Dianthus）宿主，探究了其上寄生的黑粉菌属病原菌在地理分布与宿主特异性范围内的分子变异特征。与此前针对该病原菌属的研究结论不同，本研究在石竹属宿主上发现4个已界定的黑粉菌谱系（Microbotryum lineages）存在范围重叠的宿主特异性，并在局域与区域尺度上量化了它们在单一宿主种群中的高频共现现象。除了对病原菌的直接竞争关系产生潜在影响外，黑粉菌谱系的同域分布（sympatry）还导致多个种群内发生谱系间杂交事件，且这些混合基因型（admixed genotypes）表现出显著的减数分裂不育（meiotic sterility）表型。因此，本项针对花药黑粉菌的研究揭示了宿主特化程度的差异如何对分化后的病原菌谱系的生态互作与遗传完整性产生重大影响。