Genomic Insights into the Convergence and Pathogenicity Factors of Campylobacter jejuni and Campylobacter coli Species
Genomic Insights into the Convergence and Pathogenicity Factors of Campylobacter jejuni and Campylobacter coli Species
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DOI：
10.1128/jb.00519-09
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发表时间：
2009-09-15
影响因子：
3.2
通讯作者：
Konstantinidis, Konstantinos T.
中科院分区：
文献类型：
--
作者：
Caro-Quintero, Alejandro;Rodriguez-Castano, Gina P.;Konstantinidis, Konstantinos T.
细菌是否通过遗传交换形成一致的进化群体，从而引出不同的物种边界仍然是一个悬而未决的问题。最近的一份报告暗示，不仅前者可能是真的，而且事实上，明显不同的空肠弯曲杆菌和结肠弯曲杆菌物种可能是由于物种间基因流动增加而趋同的，据推测，这是最近入侵重叠的生态位造成的（S。K. Sheppard，N. D.麦卡锡，D。Falush和M. C. Maiden，Science 320：237-239，2008）。我们重新分析了弯曲杆菌多位点序列分型数据库中使用的先前的研究，发现物种间的基因转移事件的数量可能实际上是太罕见的帐户，明确，物种收敛。例如，在4，507个被检测的弯曲杆菌分离株中，只有1%到2%似乎具有来自另一弯曲杆菌物种的输入基因等位基因。此外，通过分析可获得的弯曲杆菌基因组序列，我们表明，虽然似乎有一个稍微高的交换基因之间的C。jejuni和C.相对于其他可比较的物种（分别为基因组中总基因的10%和2 - 3%），交换基因在基因组中的功能和空间分布远非随机的，因此，与物种趋同假说不一致。事实上，交换的基因似乎仅限于少数环境选择的细胞功能。因此，这些基因可能代表致病性弯曲杆菌的重要致病决定因素，并且（任何）两种细菌物种的趋同性仍有待观察。
Whether or not bacteria form coherent evolutionary groups via means of genetic exchange and, hence, elicit distinct species boundaries remains an unsettled issue. A recent report implied that not only may the former be true but also, in fact, the clearly distinct Campylobacter jejuni and Campylobacter coli species may be converging as a consequence of increased interspecies gene flow fostered, presumably, by the recent invasion of an overlapping ecological niche (S. K. Sheppard, N. D. McCarthy, D. Falush, and M. C. Maiden, Science 320: 237-239, 2008). We have reanalyzed the Campylobacter multilocus sequence typing database used in the previous study and found that the number of interspecies gene transfer events may actually be too infrequent to account, unequivocally, for species convergence. For instance, only 1 to 2% of the 4,507 Campylobacter isolates examined appeared to have imported gene alleles from another Campylobacter species. Furthermore, by analyzing the available Campylobacter genomic sequences, we show that although there seems to be a slightly higher number of exchanged genes between C. jejuni and C. coli relative to other comparable species (similar to 10% versus 2 to 3% of the total genes in the genome, respectively), the function and spatial distribution in the genome of the exchanged genes are far from random, and hence, inconsistent with the species convergence hypothesis. In fact, the exchanged genes appear to be limited to a few environmentally selected cellular functions. Accordingly, these genes may represent important pathogenic determinants of pathogenic Campylobacter, and convergence of (any) two bacterial species remains to be seen.