Revisiting Wolbachia supergroup typing based on WSP:: Spurious lineages and discordance with MLST
Revisiting Wolbachia supergroup typing based on WSP:: Spurious lineages and discordance with MLST
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DOI：
10.1007/s00284-007-0055-8
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发表时间：
2007-07-01
影响因子：
2.6
通讯作者：
Werren, John H.
中科院分区：
文献类型：
--
作者：
Baldo, Laura;Werren, John H.
专性细胞内细菌沃尔巴克氏体在分类上被细分为八个超群（命名为A-H）。菌株的超群分型主要基于沃尔巴克氏体表面蛋白（wsp）的系统发育推断，该基因最近被证明具有高重组率。这不仅对其微分类的适用性提出了质疑，而且对属的超群分类也提出了质疑。Wolbachia的多位点序列分型（Multilocus Sequence Typing， MLST）方案最近被开发出来，该方案基于5个保守基因对菌株进行分型，从而提供了菌株的严格超群注释。在这里，我们报告了MLST和wsp推断之间超群命名的显著差异，并提出了对当前沃尔巴克氏体超群分型方法的修订。整个wsp基因序列在超群A和超群B之间发生了转移。此外，由于基因内重组，wsp系统发育产生了不被MLST支持的虚假基础谱系。例如，提出的超群G，仅基于wsp，可能只代表一个wsp重组进化支。除非该谱系的存在被其他序列信息（如MLST）证实，否则建议去除超群G。我们建议使用完整表征的MLST进行正确的菌株分型，同时，基于目前的数据集，使用单个MLST基因可以有效地进行a和B菌株的超群指定。最后，我们注意到，在A和B菌株之间共享wsp序列表明沃尔巴克氏菌菌株具有很强的遗传内聚性，支持将这些细菌指定为同一种，即W. pipientis。
The obligate intracellular bacteria Wolbachia are taxonomically subdivided into eight supergroups (named A-H). Supergroup typing of strains has been mostly based on phylogenetic inference of the Wolbachia surface protein (wsp), a gene that recently has been shown to experience high rates of recombination. This brings into question its suitability not only for microtaxonomy, but also for supergroup classification of the genus. A Multilocus Sequence Typing (MLST) scheme for Wolbachia has recently been developed that types strains based on five conserved genes, thus providing a rigorous supergroup annotation of strains. Here we report striking discrepancies in supergroup designation between MLST and wsp inferences, and propose a revision of current methods for Wolbachia supergroup typing. Transfer of whole wsp gene sequences between supergroups A and B has occurred. Furthermore, as a result of intragenic recombination, wsp phylogeny creates spurious basal lineages that are not supported by MLST. For example, the proposed supergroup G, based upon wsp alone, likely represents only a wsp recombinant clade. Removal of supergroup G is advised until and unless the existence of this lineage is substantiated by other sequence information (e.g., MLST). We recommend a full characterization MLST for a correct strain typing, while, based on the current data set, use of a single MLST gene can be effective for supergroup designation of A and B strains. Finally, we note that the sharing of wsp sequences between A and B strains indicates a strong genetic cohesiveness of Wolbachia strains, supporting designation of these bacteria within the same species, W. pipientis.