Data from: The cacao pathogen Moniliophthora roreri (Marasmiaceae) possesses biallelic A and B mating loci but reproduces clonally

The cacao pathogen Moniliophthora roreri belongs to the mushroom-forming family Marasmiaceae but it has never been observed to produce such fruiting body, which questions its sexual reproduction capability. To address this, we identified potential A (HD1 and HD2) and B (pheromone precursors and pheromone receptors) mating genes in two available genomes of M. roreri. A PCR-based method was devised to determine the mating type for a set of 47 isolates from across its geographic range, followed by an eleven-marker microsatellite analysis to find hints of sexual reproduction through association and linkage disequilibrium (standardized index of association, IAs) analyses. We also performed an ancestral reconstruction analysis to show the ancestor of M. roreri is heterothallic tetrapolar, which together with sliding window analyses support A and B mating loci are likely unlinked and follow a tetrapolar organization within the genome. The A locus is composed of a pair of HD1 and HD2 genes, whereas the B locus of a pair of a pheromone precursor, Mr_Ph4, and a receptor, STE3_Mr4. Two A and B alleles but only two mating types were identified. Association analyses divided isolates into two well-defined genetically distinct groups that correlates with their mating type; IAs values show high linkage disequilibrium as true for clonal reproduction. Interestingly, both mating types were found in South American isolates but only one mating type was found in Central American isolates, supporting a prior hypothesis of clonal dissemination throughout Central America after a single or very few introductions of the fungus from South America.可可致病菌生棒孢霉（Moniliophthora roreri）隶属于小皮伞科（Marasmiaceae），该科类群均可形成子实体，但迄今尚未观测到生棒孢霉产生任何子实体，这对其有性生殖能力提出了质疑。为解答这一疑问，本研究从两份已公布的生棒孢霉基因组中，鉴定得到潜在的A类（HD1与HD2）及B类（信息素前体与信息素受体）交配型基因。我们开发了一种基于聚合酶链式反应（PCR）的方法，对覆盖其全球地理分布范围的47株分离株进行交配型鉴定；随后开展包含11个标记位点的微卫星分析，并结合关联分析与连锁不平衡（标准化关联指数IAs）分析，以探寻其有性生殖的线索。此外，我们还进行了祖先重建分析，结果显示生棒孢霉的祖先为异宗配合四极性菌株；结合滑动窗口分析结果，证实A、B两类交配位点大概率不连锁，并在基因组中呈现四极性排布。A交配位点由一对HD1与HD2基因组成，而B交配位点则由信息素前体Mr_Ph4与受体STE3_Mr4各一个构成。本研究共鉴定出两类A等位基因与两类B等位基因，但仅存在两种交配型。关联分析将分离株划分为两个遗传特征明确的独立类群，且该类群划分与其交配型完全对应；IAs值显示其存在高度连锁不平衡，符合无性生殖的特征。值得注意的是，南美分离株中同时检测到两种交配型，而中美洲分离株仅发现一种交配型，这支持了此前的假说：生棒孢霉从南美洲单次或极少量引入后，便在中美洲范围内通过无性传播扩散。