Department of Biology, Facultad de Ciencias Naturales, Universidad de Oriente, Ave. Patricio Lumumba s/n., Santiago de Cuba, CP 90 500, Cuba.
Mol Phylogenet Evol. 2010 Feb;54(2):524-34. doi: 10.1016/j.ympev.2009.09.026. Epub 2009 Sep 26.
Xanthomonadales comprises one of the largest phytopathogenic bacterial groups, and is currently classified within the gamma-proteobacteria. However, the phylogenetic placement of this group is not clearly resolved, and the results of different studies contradict one another. In this work, the evolutionary position of Xanthomonadales was determined by analyzing the presence of shared insertions and deletions (INDELs) in highly conserved proteins. Several distinctive insertions found in most of the members of the gamma-proteobacteria are absent in Xanthomonadales and groups such as Legionelalles, Chromatiales, Methylococcales, Thiotrichales and Cardiobacteriales. These INDELs were most likely introduced after the branching of Xanthomonadales from most of the gamma-proteobacteria and provide evidence for the phylogenetic placement of the early gamma-proteobacteria. Moreover, other proteins contain insertions exclusive to the Xanthomonadales order, confirming that this is a monophyletic group and provide important specific genetic markers. Thus, the data presented clearly support the Xanthomonadales group as an independent subdivision, and constitute one of the deepest branching lineage within the gamma-proteobacteria clade.
黄单胞菌目包含了最大的植物病原细菌群体之一，目前被分类为γ-变形菌。然而，该群体的系统发育位置尚未明确解决，并且不同研究的结果相互矛盾。在这项工作中，通过分析高度保守蛋白中存在的共享插入和缺失（INDELs）来确定黄单胞菌目的进化位置。在大多数γ-变形菌中发现的几个独特插入在黄单胞菌目和军团菌目、色杆菌目、甲基球菌目、硫杆菌目和心杆菌目等群体中缺失。这些 INDELs很可能是在黄单胞菌目从大多数γ-变形菌分支后引入的，为早期γ-变形菌的系统发育位置提供了证据。此外，其他蛋白质含有仅存在于黄单胞菌目的插入，这证实了该目是一个单系群，并提供了重要的特定遗传标记。因此，所呈现的数据清楚地支持了黄单胞菌目作为一个独立的分支，并且是γ-变形菌分支中最深的分支之一。
