Bauer Robert, Garnica Sigisfredo, Oberwinkler Franz, Riess Kai, Weiß Michael, Begerow Dominik
University of Tübingen, Plant Evolutionary Ecology, Institute of Evolution and Ecology, Auf der Morgenstelle 1, 72076, Tübingen, Germany.
University of Tübingen, Department of Biology, Auf der Morgenstelle 1, 72076, Tübingen, Germany; Institute of Organismal Mycology and Microbiology, Vor dem Kreuzberg 17, 72076, Tübingen, Germany.
PLoS One. 2015 Jul 22;10(7):e0128183. doi: 10.1371/journal.pone.0128183. eCollection 2015.
Entorrhiza is a small fungal genus comprising 14 species that all cause galls on roots of Cyperaceae and Juncaceae. Although this genus was established 130 years ago, crucial questions on the phylogenetic relationships and biology of this enigmatic taxon are still unanswered. In order to infer a robust hypothesis about the phylogenetic position of Entorrhiza and to evaluate evolutionary trends, multiple gene sequences and morphological characteristics of Entorrhiza were analyzed and compared with respective findings in Fungi. In our comprehensive five-gene analyses Entorrhiza appeared as a highly supported monophyletic lineage representing the sister group to the rest of the Dikarya, a phylogenetic placement that received but moderate maximum likelihood and maximum parsimony bootstrap support. An alternative maximum likelihood tree with the constraint that Entorrhiza forms a monophyletic group with Basidiomycota could not be rejected. According to the first phylogenetic hypothesis, the teliospore tetrads of Entorrhiza represent the prototype of the dikaryan meiosporangium. The alternative hypothesis is supported by similarities in septal pore structure, cell wall and spindle pole bodies. Based on the isolated phylogenetic position of Entorrhiza and its peculiar combination of features related to ultrastructure and reproduction mode, we propose a new phylum Entorrhizomycota, for the genus Entorrhiza, which represents an apparently widespread group of inconspicuous fungi.
内生根菌属是一个小型真菌属，包含14个物种，它们都会在莎草科和灯心草科植物的根部形成虫瘿。尽管该属在130年前就已建立，但关于这个神秘类群的系统发育关系和生物学的关键问题仍未得到解答。为了推断关于内生根菌属系统发育位置的可靠假说并评估进化趋势，对内生根菌属的多个基因序列和形态特征进行了分析，并与真菌中的相应研究结果进行了比较。在我们全面的五基因分析中，内生根菌属呈现为一个得到高度支持的单系谱系，是双核菌亚界其他类群的姐妹群，这一系统发育位置仅获得了适度的最大似然法和最大简约法自展支持。一个将内生根菌属与担子菌门形成单系群作为约束条件的替代最大似然树不能被拒绝。根据第一个系统发育假说，内生根菌属的冬孢子四分体代表双核菌减数分裂孢子囊的原型。替代假说得到了隔膜孔结构、细胞壁和纺锤极体相似性的支持。基于内生根菌属孤立的系统发育位置及其与超微结构和繁殖方式相关的独特特征组合，我们为内生根菌属提出了一个新的门——内生根菌门，它代表了一类显然广泛分布但不显眼的真菌。
