Many invasive fungal species coexist as multiple lineages on the same host, but the factors underlying the origin and maintenance of population structure remain largely unknown. Here, we analyzed genetic and phenotypic diversity in isolates of the rice blast fungus (Pyricularia oryzae) covering a broad geographical range. We showed that the four lineages of P. oryzae were found in areas with different prevailing environmental conditions and types of rice grown, indicating niche separation. Pathogenicity tests revealed that specialization to rice subspecies contributed to niche separation between lineages, and differences in repertoires of putative virulence effectors were consistent with differences in host range. Experimental crosses revealed that female sterility and early post-mating genetic incompatibilities acted as strong barriers to gene flow between these lineages. Our results demonstrate that the spread of a pathogen across heterogeneous habitats and divergent populations of a crop species can lead to niche separation and reproductive isolation between distinct invasive lineages.

中文翻译：

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稻瘟病菌全球分布谱系的生态分化

许多入侵真菌物种在同一宿主上作为多个谱系共存，但种群结构起源和维持的潜在因素在很大程度上仍然未知。在这里，我们分析了覆盖广泛地理范围的稻瘟病真菌（Pyricularia oryzae）分离株的遗传和表型多样性。我们证明了P. oryzae的四个谱系在具有不同主要环境条件和水稻种植类型的地区发现了它们，表明生态位分离。致病性测试表明，对水稻亚种的特化导致了谱系之间的生态位分离，并且假定的毒力效应物库的差异与宿主范围的差异一致。实验杂交表明，雌性不育和交配后早期的遗传不相容性是这些谱系之间基因流动的强大障碍。我们的研究结果表明，病原体在异质栖息地和作物物种的不同种群中的传播会导致不同入侵谱系之间的生态位分离和生殖隔离。