Genome sequence of Blochmannia pennsylvanicus indicates parallel evolutionary trends among bacterial mutualists of insects
Genome sequence of Blochmannia pennsylvanicus indicates parallel evolutionary trends among bacterial mutualists of insects
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DOI：
10.1101/gr.3771305
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发表时间：
2005-08-01
期刊：
影响因子：
7
通讯作者：
Wernegreen, JJ
中科院分区：
文献类型：
--
作者：
Degnan, PH;Lazarus, AB;Wernegreen, JJ
专性细胞内细菌的独特生活方式改变了驱动和限制基因组变化的基本力量。在这项研究中，测序的792-kb的基因组Blochmannia pennaculicus，专性内共生体Camponotus pennaculicus，使LIS跟踪进化的变化，发生在细菌蚂蚁协会的背景下。与Blochmannia floridanus基因组的比较揭示了参与辅因子生物合成、细胞壁和膜的组成和结构、基因调控和DNA复制的基因的差异丢失。然而，这两种Blochmannia物种显示完全保守的顺序和链方向的共享基因。这一发现的基因组结构中的极端停滞，以前也报道了蚜虫内共生体Buchnera，表明基因组稳定性的特点是长期的细菌互利的昆虫和限制其进化潜力。对蛋白质差异的全基因组分析显示，与相关细菌相比，Blochmannia中的氨基酸取代速率快10至50倍。尽管基因组进化有这些不同的特征，但蛋白质相对差异的显著相关性表明，在生态学上不同的细菌群体中，基因功能存在平行的功能限制。此外，Blochmannia的氨基酸替换率和基因丢失率的增加具有谱系特异性，这可能反映了其蚂蚁宿主的生活史差异。
The distinct lifestyle of obligately intracellular bacteria call alter fundamental forces that drive and constrain genome change. In this Study, sequencing the 792-kb genome of Blochmannia pennsylvanicus, an obligate endosymbiont of Camponotus pennsylvanicus, enabled LIS to trace evolutionary changes that occured in the context of a bacterial-ant association. Comparison to the genome of Blochmannia floridanus reveals differential loss of genes involved in cofactor biosynthesis, the composition and structure of the cell wall and membrane, gene regulation, and DNA replication. However, the two Blochmannia species show complete conservation in the order and strand orientation of shared genes. This finding of extreme stasis in genome architecture, also reported previously for the aphid endosymbiont Buchnera, Suggests that genome stability characterizes long-term bacterial mutualists of insects and constrains their evolutionary potential. Genome-wide analyses of protein divergences reveal 10- to 50-fold faster amino acid Substitution rates in Blochmannia compared to related bacteria. Despite these varying features of genome evolution, a striking correlation in the relative divergences of proteins indicates parallel functional constraints oil gene functions across ecologically distinct bacterial groups. furthermore, the increased rates of amino acid substitution and gene loss in Blochmannia have Occurred in a lineage-specific fashion, which may reflect life history differences of their ant hosts.