Gavotte Laurent, Henri Hélène, Stouthamer Richard, Charif Delphine, Charlat Sylvain, Boulétreau Michel, Vavre Fabrice
Laboratoire de Biométrie et Biologie Evolutive (UMR 5558), CNRS, IFR 41, University Lyon 1, Villeurbanne, France.
Mol Biol Evol. 2007 Feb;24(2):427-35. doi: 10.1093/molbev/msl171. Epub 2006 Nov 9.
Bacteriophages are common viruses infecting prokaryotes. In addition to their deadly effect, phages are also involved in several evolutionary processes of bacteria, such as coding functional proteins potentially beneficial to them, or favoring horizontal gene transfer through transduction. The particular lifestyle of obligatory intracellular bacteria usually protects them from phage infection. However, Wolbachia, an intracellular alpha-proteobacterium, infecting diverse arthropod and nematode species and best known for the reproductive alterations it induces, harbors a phage named WO, which has recently been proven to be lytic. Here, phage infection was checked in 31 Wolbachia strains, which induce 5 different effects in their hosts and infect 25 insect species and 3 nematodes. Only the Wolbachia infecting nematodes and Trichogramma were found devoid of phage infection. All the 25 detected phages were characterized by the DNA sequence of a minor capsid protein gene. Based on all data currently available, phylogenetic analyses show a lack of congruency between Wolbachia or insect and phage WO phylogenies, indicating numerous horizontal transfers of phage among the different Wolbachia strains. The absence of relation between phage phylogeny and the effects induced by Wolbachia suggests that WO is not directly involved in these effects. Implications on phage WO evolution are discussed.
噬菌体是感染原核生物的常见病毒。除了具有致命作用外，噬菌体还参与细菌的多种进化过程，例如编码可能对它们有益的功能蛋白，或通过转导促进水平基因转移。 obligatory intracellular bacteria的特殊生活方式通常可保护它们免受噬菌体感染。然而，沃尔巴克氏体（Wolbachia）是一种细胞内α-变形菌，感染多种节肢动物和线虫物种，并以其诱导的生殖改变而闻名，它携带一种名为WO的噬菌体，最近已被证明具有裂解性。在此，对31种沃尔巴克氏体菌株进行了噬菌体感染检测，这些菌株在其宿主中诱导5种不同的效应，并感染25种昆虫物种和3种线虫。仅发现感染线虫和赤眼蜂的沃尔巴克氏体没有噬菌体感染。所有检测到的25种噬菌体均通过次要衣壳蛋白基因的DNA序列进行了表征。根据目前所有可用数据，系统发育分析表明，沃尔巴克氏体或昆虫与噬菌体WO的系统发育之间缺乏一致性，这表明噬菌体在不同沃尔巴克氏体菌株之间进行了大量水平转移。噬菌体系统发育与沃尔巴克氏体诱导的效应之间不存在关联，这表明WO与这些效应没有直接关系。本文讨论了对噬菌体WO进化的影响。
