Comparative genomics provides a timeframe for Wolbachia evolution and exposes a recent biotin synthesis operon transfer
Comparative genomics provides a timeframe for Wolbachia evolution and exposes a recent biotin synthesis operon transfer
复制标题
DOI：
10.1038/nmicrobiol.2016.241
复制
发表时间：
2017-03-01
影响因子：
28.3
通讯作者：
Bleidorn, Christoph
中科院分区：
文献类型：
--
作者：
Gerth, Michael;Bleidorn, Christoph
Wolbachia属（Alphaproteobacteria）由最丰富的遗传胞内细菌组成(1)。尽管它们是人类病原体传播(2)和节肢动物繁殖(3)的操纵者，但它们进化史的许多方面还没有得到很好的理解(4)。在节肢动物中，沃尔巴克氏体感染在进化时间尺度上通常是短暂的（5,6），宿主和沃尔巴克氏体之间的共同分化被认为是罕见的。因此，我们对沃尔巴克氏体基因组进化的大部分知识来自最近分化的菌株，缺乏沃尔巴克氏体的时间尺度。在这里，我们研究了四种沃尔巴克氏菌菌株的基因组，这些菌株在宿主谱系中持续存在并与宿主谱系共分化了大约200万年。尽管基因组在核苷酸水平上显示出很少的进化变化，但我们发现证据表明，最近一个完整的生物素合成操纵子的横向转移有可能改变沃尔巴克氏体与宿主的关系(7)。此外，这一进化快照使我们能够使用全基因组数据集和宽松的分子钟模型校准超群A和B沃尔巴克氏体谱系的分化时间。我们估计沃尔巴克氏体超群A和B的起源类似于2亿年前（Ma），这比之前认为的要早得多。这个时代与许多昆虫谱系的多样化相吻合，这些谱系代表了沃尔巴克氏菌的大部分寄主谱系。
The genus Wolbachia (Alphaproteobacteria) comprises the most abundant inherited intracellular bacteria(1). Despite their relevance as manipulators of human pathogen transmission(2) and arthropod reproduction(3), many aspects of their evolutionary history are not well understood(4). In arthropods, Wolbachia infections are typically transient on evolutionary timescales(5,6) and co-divergence between hosts and Wolbachia is supposedly rare. Consequently, much of our knowledge of Wolbachia genome evolution derives from very recently diverged strains, and a timescale for Wolbachia is lacking. Here, we investigated the genomes of four Wolbachia strains that have persisted within and co-diverged with their host lineage for similar to 2 million years. Although the genomes showed very little evolutionary change on a nucleotide level, we found evidence for a recent lateral transfer of a complete biotin synthesis operon that has the potential to transform Wolbachia-host relationships(7). Furthermore, this evolutionary snapshot enabled us to calibrate the divergence times of the supergroup A and B Wolbachia lineages using genome-wide data sets and relaxed molecular clock models. We estimated the origin of Wolbachia supergroups A and B to be similar to 200 million years ago (Ma), which is considerably older than previously appreciated. This age coincides with the diversification of many insect lineages(8) that represent most of Wolbachia's host spectrum.