Goldmann Lauren, Weir Alex
Department of Biological Sciences, The State University of New York at Cortland, Cortland, NY 13045, USA.
Department of Environmental and Forest Biology, The State University of New York College of Environmental Science and Forestry, Syracuse, NY 13210, USA.
Fungal Biol. 2018 Feb-Mar;122(2-3):87-100. doi: 10.1016/j.funbio.2017.11.004. Epub 2017 Dec 1.
A first molecular-based phylogeny is presented for the Laboulbeniomycetes, a group of ascomycete fungi that utilize arthropods for nutrition and/or dispersal. Morphological diversification and life-history evolution has made it difficult to resolve relationships within the group, and to identify close relatives. Here, we infer a preliminary phylogeny based on acquisition of 51 new SSU rDNA sequences, representing a total of 65 taxa. The results of this study demonstrate that Laboulbeniomycetes is monophyletic, and related to Sordariomycetes. The class could be divided into at least 4 or 5 orders, though we refrain from formally giving names to these at this stage. Further evidence for the occurrence of asexuality within the class is provided by the inclusion of the genera Chantransiopsis and Tetrameronycha, both known only as asexual taxa with thalli consisting of linearly superposed cells. The precise placement of the genus Herpomyces (Herpomycetaceae), on cockroaches, remains unresolved in our analysis, but lies outside of the main clade of sexually reproducing Laboulbeniales. There is good support for this latter grouping, comprising taxa that are found on both aquatic and terrestrial hosts. Within this large assemblage, we recognize 5 distinct clades (clades E, F, G, H, I). Relationships among the so-called "aquatic genera" (≡ Ceratomycetaceae + some Euceratomycetaceae and Zodiomyces) are poorly resolved in our analyses, accounting for 3 of these clades (E, F, G), with the remainder of the taxa (largely equivalent to Laboulbeniaceae) split into two major groupings (clades H, I). Across all taxa, antheridial characteristics, features on which the earliest classifications were based, are shown to be homoplastic. On the other hand, features of perithecial development show an overall trend towards reduction, and appear to be phylogenetically informative. Morphological characters are identified that support the dichotomy in the Laboulbeniaceae and subclades within the two major groupings are discussed further in light of information on thallus morphology, development, and host relationships.
本文给出了首个基于分子数据的虫囊菌纲系统发育树，虫囊菌纲是一类子囊菌真菌，它们利用节肢动物获取营养和/或传播。形态多样性和生活史演化使得解析该类群内部的关系以及识别近亲变得困难。在此，我们基于51个新的小亚基核糖体DNA（SSU rDNA）序列构建了一个初步的系统发育树，这些序列代表了总共65个分类单元。本研究结果表明，虫囊菌纲是单系的，并且与粪壳菌纲相关。该纲可分为至少4个或5个目，不过我们在此阶段暂不正式为它们命名。将Chantransiopsis属和Tetrameronycha属纳入研究，为该纲内无性生殖的存在提供了进一步证据，这两个属仅为无性分类单元，其菌体由线性叠加的细胞组成。在我们的分析中，寄生于蟑螂的Herpomyces属（Herpomycetaceae科）的精确位置仍未确定，但位于有性生殖的虫囊菌目主要分支之外。对后一组群有很好的支持，该组群包括在水生和陆生宿主上发现的分类单元。在这个大的类群中，我们识别出5个不同的分支（分支E、F、G、H、I）。在我们的分析中，所谓“水生属”（≡角囊菌科+一些真角囊菌科和Zodiomyces属）之间的关系解析得很差，它们占了其中3个分支（E、F、G），其余的分类单元（大致相当于虫囊菌科）分为两个主要类群（分支H、I）。在所有分类单元中，最早分类所依据的雄器特征显示为非同源相似。另一方面，子囊壳发育特征呈现出整体的简化趋势，并且似乎在系统发育上具有信息价值。我们识别出了支持虫囊菌科二分法的形态特征，并根据菌体形态、发育和宿主关系的信息，进一步讨论了两个主要类群中的亚分支。
