The chimeric nature of the genomes of marine magnetotactic coccoid-ovoid bacteria defines a novel group of Proteobacteria
The chimeric nature of the genomes of marine magnetotactic coccoid-ovoid bacteria defines a novel group of Proteobacteria
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DOI：
10.1111/1462-2920.13637
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发表时间：
2017-03-01
影响因子：
5.1
通讯作者：
Wu, Long-Fei
中科院分区：
文献类型：
--
作者：
Ji, Boyang;Zhang, Sheng-Da;Wu, Long-Fei
趋磁细菌（MTB）是一类在遗传和生理上具有多样性的革兰氏阴性细菌，其细胞内可合成称为磁小体的磁性晶体。MTB隶属于变形菌门（Proteobacteriaphylum）、硝化菌门（Nitrosspiphylum）、全硝化菌门（Omnitrophica phylum）三个纲，并可能隶属于候选菌门（Latescibacteria）。与其他细菌分类群相比，MTB的进化起源和生理多样性仍有待阐明。本文对海洋磁性卵形体菌株MO-1的基因组进行了分析，发现其与海洋磁球菌MC-1有很近的亲缘关系。对390个基因组的核糖体蛋白和全蛋白质组的详细分析表明，在分析的变形菌中，只有MO-1和MC-1具有类似高比例的来自α变形菌、β变形菌、δ变形菌和γ变形菌的编码序列（CDS）。有趣的是，与缺氧网络酶从测序MTB和非MTB的比较代谢网络分析成功地允许最终预测的生物体与代谢谱兼容的磁小体生产。总之，我们的基因组分析揭示了MO-1和M的多个起源。marinus MC-1基因组，并提出了一种代谢限制模型，用于解释细菌是否可以成为MTB后，收购磁小体编码基因。
Magnetotactic bacteria (MTB) are a group of phylogenetically and physiologically diverse Gram-negative bacteria that synthesize intracellular magnetic crystals named magnetosomes. MTB are affiliated with three classes of Proteobacteria phylum, Nitrospirae phylum, Omnitrophica phylum and probably with the candidate phylum Latescibacteria. The evolutionary origin and physiological diversity of MTB compared with other bacterial taxonomic groups remain to be illustrated. Here, we analysed the genome of the marine magneto-ovoid strain MO-1 and found that it is closely related to Magnetococcus marinus MC-1. Detailed analyses of the ribosomal proteins and whole proteomes of 390 genomes reveal that, among the Proteobacteria analysed, only MO-1 and MC-1 have coding sequences (CDSs) with a similarly high proportion of origins from Alphaproteobacteria, Betaproteobacteria, Deltaproteobacteria and Gammaproteobacteria. Interestingly, a comparative metabolic network analysis with anoxic network enzymes from sequenced MTB and non-MTB successfully allows the eventual prediction of an organism with a metabolic profile compatible for magnetosome production. Altogether, our genomic analysis reveals multiple origins of MO-1 and M. marinus MC-1 genomes and suggests a metabolism-restriction model for explaining whether a bacterium could become an MTB upon acquisition of magnetosome encoding genes.