Percudani R, Trevisi A, Zambonelli A, Ottonello S
Istituto di Scienze Biochimiche, Università di Parma, Parma, I-43100, Italy.
Mol Phylogenet Evol. 1999 Oct;13(1):169-80. doi: 10.1006/mpev.1999.0638.
Extensive morphological convergence or divergence, a common occurrence in fungi, tends to obscure recognition of phylogenetic relationships among Pezizales, widespread filamentous Ascomycetes with either enclosed underground (hypogeous) or exposed (epigeous) fruit bodies, that often establish mutualistic interactions with arboreous plants. Focusing on hypogeous Pezizales commonly known as truffles, we sequenced the 18S rDNA from nine species belonging to three different families (Tuberaceae, Terfeziaceae, and Balsamiaceae). A data set consisting of 1700 secondary structure-aligned sites, including 24 homologous sequences from the GenBank DNA database and using three reconstruction methods, was employed to infer phylogenies in an interval ranging from the subordinal to the subgeneric level. As revealed by the 18S phylogenetic scheme, Balsamiaceae represent a monophyletic clade, comprising the hypogeous taxa Balsamia and Barssia, nested within Helvellaceae. Similarly, the terfeziacean genera Pachyphloeus and Terfezia constitute together with Cazia a distinct hypogeous clade nested within Pezizaceae. The lack of clustering between Terfezia arenaria and Terfezia terfezioides strongly supports the reassignment of the latter taxon to the original monotypic genus Mattirolomyces. Within Tuberaceae, which are sister to the highly evolved Helvellaceae, the genus Tuber cannot be considered monophyletic if Choiromyces is recognized. The paraphyly of Tuber and other relationships that were not supported by high bootstrap values, nor corroborated by morphological evidence, were supported by a parallel analysis of the faster evolving internal transcribed spacer (ITS) rDNA. Distinct episodes of fruit body morphology shifts are discernable in the 18S rDNA phylogenetic tree. In all cases, the shift from an epigeous to a hypogeous form is the most parsimonious interpretation of character transformation, without any instance of character reversal.
广泛的形态趋同或趋异在真菌中很常见，这往往会模糊盘菌目（Pezizales）真菌之间系统发育关系的识别。盘菌目是广泛分布的丝状子囊菌，其子实体要么封闭于地下（地下生），要么暴露在外（地上生），并且常常与木本植物建立共生关系。我们聚焦于通常被称为块菌的地下生盘菌目真菌，对隶属于三个不同科（块菌科、地菇科和香脂盘菌科）的九个物种的18S核糖体DNA（rDNA）进行了测序。使用了一个由1700个二级结构比对位点组成的数据集，包括来自GenBank DNA数据库的24个同源序列，并采用三种重建方法，来推断从亚目到亚属水平区间内的系统发育。正如18S系统发育方案所揭示的，香脂盘菌科代表一个单系类群，包括地下生物种香脂盘菌属（Balsamia）和巴氏盘菌属（Barssia），嵌套在马鞍菌科（Helvellaceae）内。同样，地菇科的厚皮盘菌属（Pachyphloeus）和地菇属（Terfezia）与卡齐亚属（Cazia）一起构成了一个独特的地下生类群，嵌套在盘菌科（Pezizaceae）内。沙质地菇（Terfezia arenaria）和地菇（Terfezia terfezioides）之间缺乏聚类，有力地支持了将后者重新归入原来的单型属马蒂罗块菌属（Mattirolomyces）。在与高度进化的马鞍菌科为姐妹群的块菌科内，如果承认拟块菌属（Choiromyces），则块菌属（Tuber）不能被视为单系的。块菌属的并系性以及其他未得到高自展值支持、也未得到形态学证据证实的关系，通过对进化较快的内部转录间隔区（ITS）rDNA的平行分析得到了支持。在18S rDNA系统发育树中可以辨别出子实体形态转变的不同阶段。在所有情况下，从地上生形态到地下生形态的转变是对性状转变最简约的解释，没有任何性状逆转的情况。
