Analysis of Ten Brucella Genomes Reveals Evidence for Horizontal Gene Transfer Despite a Preferred Intracellular Lifestyle
Analysis of Ten Brucella Genomes Reveals Evidence for Horizontal Gene Transfer Despite a Preferred Intracellular Lifestyle
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DOI：
10.1128/jb.01767-08
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发表时间：
2009-04
影响因子：
3.2
通讯作者：
A. Wattam;K. Williams;E. Snyder;N. Almeida;N. Almeida;Maulik Shukla;A. Dickerman;O. Crasta;
中科院分区：
文献类型：
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作者：
A. Wattam;K. Williams;E. Snyder;N. Almeida;N. Almeida;Maulik Shukla;A. Dickerman;O. Crasta;
摘要布鲁氏菌是一种兼性胞内细菌病原体，广泛感染陆地和海洋温血脊椎动物，引起布鲁氏菌病。目前，根据宿主偏好和表型差异，有9种公认的布鲁氏菌。10个不同的基因组的可用性由两条染色体组成，代表了6个物种，允许在根瘤菌目中进行详细的比较。直系同源家族的系统基因组分析显示有限的分歧，但不同的辐射，产生四个分支如下：流产布鲁氏菌-羊种布鲁氏菌，猪种布鲁氏菌-犬种布鲁氏菌，羊种布鲁氏菌和鲸种布鲁氏菌。此外，布鲁氏菌的繁殖力似乎并不反映布鲁氏菌属的首选宿主的繁殖力。大约4.6%的蛋白质编码基因似乎是假基因，这是一个相对较大的比例。只有B。SUIS 1330似乎具有完整的β-酮己二酸途径，负责利用植物衍生的化合物。相反，在其他物种中的这一途径是高度假基因化的，与基因死亡的“多米诺骨牌理论”一致。有不同的共享异常区域（SAR）发现在两条染色体上的水平基因转移独特的布鲁氏菌，而不是共享其最近的亲戚苍白杆菌，土壤细菌，这表明他们的收购发生，尽管主要是细胞内的生活方式。特别是，SAR 2-5似乎是在布鲁氏菌进入细胞内后被布鲁氏菌获得的。SAR含有许多基因，包括参与O-多糖合成和IV型分泌的基因，如果突变或缺失，则会显著影响布鲁氏菌在感染宿主细胞内存活的能力。
ABSTRACT The facultative intracellular bacterial pathogen Brucella infects a wide range of warm-blooded land and marine vertebrates and causes brucellosis. Currently, there are nine recognized Brucella species based on host preferences and phenotypic differences. The availability of 10 different genomes consisting of two chromosomes and representing six of the species allowed for a detailed comparison among themselves and relatives in the order Rhizobiales. Phylogenomic analysis of ortholog families shows limited divergence but distinct radiations, producing four clades as follows: Brucella abortus-Brucella melitensis, Brucella suis-Brucella canis, Brucella ovis, and Brucella ceti. In addition, Brucella phylogeny does not appear to reflect the phylogeny of Brucella species' preferred hosts. About 4.6% of protein-coding genes seem to be pseudogenes, which is a relatively large fraction. Only B. suis 1330 appears to have an intact β-ketoadipate pathway, responsible for utilization of plant-derived compounds. In contrast, this pathway in the other species is highly pseudogenized and consistent with the “domino theory” of gene death. There are distinct shared anomalous regions (SARs) found in both chromosomes as the result of horizontal gene transfer unique to Brucella and not shared with its closest relative Ochrobactrum, a soil bacterium, suggesting their acquisition occurred in spite of a predominantly intracellular lifestyle. In particular, SAR 2-5 appears to have been acquired by Brucella after it became intracellular. The SARs contain many genes, including those involved in O-polysaccharide synthesis and type IV secretion, which if mutated or absent significantly affect the ability of Brucella to survive intracellularly in the infected host.