James Timothy Y, Letcher Peter M, Longcore Joyce E, Mozley-Standridge Sharon E, Porter David, Powell Martha J, Griffith Gareth W, Vilgalys Rytas
Department of Biology, Duke University, Durham, North Carolina 27708, USA.
Mycologia. 2006 Nov-Dec;98(6):860-71. doi: 10.3852/mycologia.98.6.860.
Chytridiomycota (chytrids) is the only phylum of true Fungi that reproduces with motile spores (zoospores). Chytrids currently are classified into five orders based on habitat, zoospore characters and life cycles. In this paper we estimate the phylogeny of the chytrids with DNA sequences from the ribosomal RNA operon (18S+5.8S+28S subunits). To our surprise the morphologically reduced parasites Olpidium and Rozella comprise two entirely new, and separate, lineages on the fungal tree. Olpidium brassicae groups among the Zygomycota, and Rozella spp. are the earliest branch to diverge in the fungal kingdom. The phylogeny also suggests that Chytridiomycota is not monophyletic and there are four major lineages of chytrids: Rozella spp., Olpidium brassicae, the Blastocladiales and a "core chytrid clade" containing the remaining orders and families and the majority of flagellated fungi. Within the core chytrid group 11 subclades can be identified, each of which correlates well with zoospore ultrastructure or morphology. We provide a synopsis of each clade and its morphological circumscription. The Blastocladiales appears to be the sister taxon of most nonflagellated fungi. Based on molecular phylogenetic and ultrastructural characters this order is elevated to a phylum, the Blastocladiomycota.
壶菌门（壶菌）是唯一一类通过游动孢子（游动孢子）进行繁殖的真正真菌。目前，壶菌根据栖息地、游动孢子特征和生命周期被分为五个目。在本文中，我们利用核糖体RNA操纵子（18S + 5.8S + 28S亚基）的DNA序列来估计壶菌的系统发育。令我们惊讶的是，形态上退化的寄生菌油壶菌属和集壶菌属在真菌树上构成了两个全新且独立的谱系。芸苔油壶菌归在接合菌门中，而集壶菌属物种是真菌界最早分化出来的分支。系统发育还表明，壶菌门并非单系类群，壶菌有四个主要谱系：集壶菌属物种、芸苔油壶菌、芽枝霉目以及一个“核心壶菌分支”，其中包含其余的目和科以及大多数具鞭毛的真菌。在核心壶菌组内可以识别出11个亚分支，每个亚分支都与游动孢子的超微结构或形态密切相关。我们提供了每个分支及其形态界定的概述。芽枝霉目似乎是大多数非具鞭毛真菌的姐妹分类单元。基于分子系统发育和超微结构特征，这个目被提升为一个门，即芽枝霉门。
