Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.
PLoS One. 2011;6(11):e27909. doi: 10.1371/journal.pone.0027909. Epub 2011 Nov 18.
Members of the genus Xenorhabdus are entomopathogenic bacteria that associate with nematodes. The nematode-bacteria pair infects and kills insects, with both partners contributing to insect pathogenesis and the bacteria providing nutrition to the nematode from available insect-derived nutrients. The nematode provides the bacteria with protection from predators, access to nutrients, and a mechanism of dispersal. Members of the bacterial genus Photorhabdus also associate with nematodes to kill insects, and both genera of bacteria provide similar services to their different nematode hosts through unique physiological and metabolic mechanisms. We posited that these differences would be reflected in their respective genomes. To test this, we sequenced to completion the genomes of Xenorhabdus nematophila ATCC 19061 and Xenorhabdus bovienii SS-2004. As expected, both Xenorhabdus genomes encode many anti-insecticidal compounds, commensurate with their entomopathogenic lifestyle. Despite the similarities in lifestyle between Xenorhabdus and Photorhabdus bacteria, a comparative analysis of the Xenorhabdus, Photorhabdus luminescens, and P. asymbiotica genomes suggests genomic divergence. These findings indicate that evolutionary changes shaped by symbiotic interactions can follow different routes to achieve similar end points.
属 Xenorhabdus 的细菌是与线虫共生的昆虫病原细菌。线虫-细菌对昆虫的感染和杀伤，双方都有助于昆虫发病机制，细菌从可用的昆虫衍生营养物质中为线虫提供营养。线虫为细菌提供免受捕食者侵害、获取营养的机会和传播机制的保护。 Photorhabdus 属的细菌也与线虫共生以杀死昆虫，并且这两个细菌属通过独特的生理和代谢机制为它们不同的线虫宿主提供类似的服务。我们假设这些差异将反映在它们各自的基因组中。为了验证这一点，我们完成了 Xenorhabdus nematophila ATCC 19061 和 Xenorhabdus bovienii SS-2004 的基因组测序。正如预期的那样， Xenorhabdus 的两个基因组都编码了许多抗昆虫的化合物，与它们的昆虫病原生活方式相一致。尽管 Xenorhabdus 和 Photorhabdus 细菌的生活方式相似，但 Xenorhabdus、Photorhabdus luminescens 和 P. asymbiotica 基因组的比较分析表明基因组的分歧。这些发现表明，由共生相互作用塑造的进化变化可以遵循不同的途径来达到相似的终点。
