Data from: Molecular characterization of sexual diversity in a population of Serpula lacrymans, a tetrapolar basidiomycete

Different mating systems have evolved in the fungal kingdom, including a tetrapolar multiallelic mating system in many basidiomycetes. In tetrapolar species, the presence of different alleles at two mating loci (MAT A and MAT B) is necessary for mating to occur. The tetrapolar fungus Serpula lacrymans causes wood-decay in buildings in temperate regions worldwide and is present in Europe with a genetically homogeneous founder population. Using genome sequence data, we annotated the two mating type loci for S. lacrymans and found the expected synteny with other basidiomycetes, except for a retrotransposon being present in one locus (MAT A). We developed markers linked to the MAT A and MAT B regions and used these to investigate the mating type diversity in the European population. Moreover, we found a good match between the genetic markers and functional mating types as revealed by segregation and mating studies. A low diversity of mating types is present in the European S. lacrymans population caused by the founder event where a limited number of genotypes were introduced. This finding contrasts the situation in natural fungal populations where a high diversity of mating types is normally present. Although S. lacrymans has a large and viable population in Europe, we argue that the low mating type diversity restrains the dispersal and establishment of the fungus.

真菌界已演化出多种交配系统，其中诸多担子菌（basidiomycetes）具备四极多等位基因交配系统（tetrapolar multiallelic mating system）。在四极物种中，需在两个交配位点（MAT A与MAT B）携带不同等位基因，方可完成交配过程。四极真菌密粘褶菌（Serpula lacrymans）可在全球温带区域的建筑内引发木材腐朽，且在欧洲存在一个遗传同质化的奠基者种群（founder population）。本研究通过基因组测序数据，对密粘褶菌的两个交配型位点进行了注释，发现其与其他担子菌存在预期的共线性（synteny），仅在其中一个位点（MAT A）中存在反转录转座子（retrotransposon）。我们开发了与MAT A和MAT B区域连锁的遗传标记，并利用这些标记对欧洲种群的交配型多样性展开了研究。此外，通过分离分析与交配实验证实，遗传标记与功能交配型之间具有良好的对应关系。由于奠基者事件——即仅有限数量的基因型被引入欧洲——该区域的密粘褶菌种群交配型多样性较低。这一发现与自然真菌种群的普遍情况相悖：自然真菌种群通常具备较高的交配型多样性。尽管密粘褶菌在欧洲拥有规模庞大且存活能力较强的种群，但我们认为，较低的交配型多样性会抑制该真菌的扩散与定殖。