Mating-type genes are central to sexual reproduction in ascomycete fungi and result in the establishment of reproductive barriers. Together with hybridization, they both play important roles in the evolution of fungi. Recently, potential hybridization events and MAT genes were separately found in the Elata Clade of Morchella. Herein, we characterized the MAT1–1-1 and MAT1–2-1 genes of twenty-two species in the Esculenta Clade, another main group in the genus Morchella, and proved heterothallism to be the predominant mating strategy among the twenty-two species tested. Ascospores of these species were multi-nuclear and had many mitochondrial nucleoids. The number of ascospore nuclei might be positively related with the species distribution range. Phylogenetic analyses of MAT1–1-1, MAT1–2-1, intergenic spacer (IGS), and partial histone acetyltransferase ELP3 (F1) were performed and compared with the species phylogeny framework derived from the ribosomal internal transcribed spacer region (ITS) and translation elongation factor 1-alpha (EF1-a) to evaluate their species delimitation ability and investigate potential hybridization events. Conflicting topologies among these genes genealogies and the species phylogeny were revealed and hybridization events were detected between several species. Different evolutionary patterns were suggested for MAT genes between the Esculenta and the Elata Clades. Complex evolutionary trajectories of MAT1–1-1, MAT1–2-1, F1 and IGS in the Esculenta Clade were highlighted. These findings contribute to a better understanding of the importance of hybridization and gene transfer in Morchella and especially for the appearance of reproductive modes during its evolutionary process.

中文翻译：

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推断出 22 种黄羊肚菌的异种性和潜在杂交事件。

交配型基因是子囊菌有性生殖的核心，并导致生殖障碍的建立。与杂交一起，它们都在真菌的进化中发挥着重要作用。最近，在羊肚菌的 Elata Clade 中分别发现了潜在的杂交事件和 MAT 基因。在这里，我们表征了羊肚菌属的另一个主要群体 Esculenta Clade 中 22 个物种的 MAT1-1-1 和 MAT1-2-1 基因，并证明异质性是这 22 个物种中的主要交配策略测试。这些物种的子囊孢子是多核的并且有许多线粒体类核。子囊孢子核的数量可能与物种分布范围呈正相关。MAT1-1-1、MAT1-2-1、基因间隔区 (IGS) 的系统发育分析，和部分组蛋白乙酰转移酶 ELP3 (F1) 进行并与源自核糖体内部转录间隔区 (ITS) 和翻译延伸因子 1-α (EF1-a) 的物种系统发育框架进行比较，以评估它们的物种划界能力并研究潜在的杂交事件。揭示了这些基因谱系和物种系统发育之间的冲突拓扑，并检测了几个物种之间的杂交事件。对 Esculenta 和 Elata Clades 之间的 MAT 基因提出了不同的进化模式。强调了 Esculenta Clade 中 MAT1-1-1、MAT1-2-1、F1 和 IGS 的复杂进化轨迹。