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.

宿主专化性对专性病原体的多样化进程与生态互作具有重要影响。由黑粉菌属（Microbotryum）真菌引发的野生植物种群花药黑粉病，其典型特征为专化性的宿主-病原体互作，该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。本研究针对南欧洲阿尔卑斯山区域野生石竹属（Dianthus）宿主上、兼具地理分布与宿主专化性特征的黑粉菌属病原体，开展了分子变异层面的调查。与该病原真菌类群此前的研究结论不同，本研究在石竹属宿主上观测到4个已界定的黑粉菌谱系存在一系列重叠的宿主专化性特征，并在局地与区域尺度上量化了它们在单一宿主种群内的高频共现现象。除了可能对病原体间的直接竞争产生影响外，黑粉菌谱系的同域分布还促使多个种群内的谱系间发生杂交，且这些混合基因型个体表现出显著的减数分裂不育缺陷。因此，本项针对花药黑粉真菌的研究揭示了宿主专化性程度的差异，如何对已分化的病原谱系的生态互作与遗传完整性产生重要影响。