Skalický Tomáš, Alves João M P, Morais Anderson C, Režnarová Jana, Butenko Anzhelika, Lukeš Julius, Serrano Myrna G, Buck Gregory A, Teixeira Marta M G, Camargo Erney P, Sanders Mandy, Cotton James A, Yurchenko Vyacheslav, Kostygov Alexei Y
Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice (Budweis), Czech Republic.
Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil.
Pathogens. 2021 Jun 4;10(6):702. doi: 10.3390/pathogens10060702.
Trypanosomatids of the subfamily Strigomonadinae bear permanent intracellular bacterial symbionts acquired by the common ancestor of these flagellates. However, the cospeciation pattern inherent to such relationships was revealed to be broken upon the description of , which is sister to , but bears an endosymbiont genetically close to that of . Based on phylogenetic inferences, it was proposed that the bacterium from had been horizontally transferred to . Here, we sequenced the bacterial genomes from two isolates, including a new one from Papua New Guinea, and compared them with the published genome of the endosymbiont, revealing differences below the interspecific level. Our phylogenetic analyses confirmed that the endosymbionts of were obtained from and, in addition, demonstrated that this occurred more than once. We propose that coinfection of the same blowfly host and the phylogenetic relatedness of the trypanosomatids facilitate such transitions, whereas the drastic difference in the occurrence of the two trypanosomatid species determines the observed direction of this process. This phenomenon is analogous to organelle (mitochondrion/plastid) capture described in multicellular organisms and, thereafter, we name it endosymbiont capture.
锥虫亚科斯特里戈莫纳德亚科的锥虫带有永久性细胞内细菌共生体，这些共生体是由这些鞭毛虫的共同祖先获得的。然而，在对[物种名称1]进行描述后发现，这种关系中固有的共物种形成模式被打破了，[物种名称1]是[物种名称2]的姐妹种，但携带一种在遗传上与[物种名称2]的内共生体相近的内共生体。基于系统发育推断，有人提出来自[物种名称1]的细菌已横向转移到[物种名称2]。在这里，我们对来自两个[物种名称1]分离株的细菌基因组进行了测序，包括一个来自巴布亚新几内亚的新分离株，并将它们与已发表的[物种名称2]内共生体基因组进行了比较，揭示了种间水平以下的差异。我们的系统发育分析证实，[物种名称1]的内共生体是从[物种名称2]获得的，此外，还证明这种情况发生了不止一次。我们提出，同一蝇类宿主的共感染以及锥虫的系统发育相关性促进了这种转变，而两种锥虫物种出现频率的巨大差异决定了这一过程中观察到的方向。这种现象类似于多细胞生物中描述的细胞器（线粒体/质体）捕获，因此，我们将其命名为内共生体捕获。
