The Genome Organization of Ralstonia eutropha Strain H16 and Related Species of the Burkholderiaceae
The Genome Organization of Ralstonia eutropha Strain H16 and Related Species of the Burkholderiaceae
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DOI：
10.1159/000142899
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发表时间：
2009-01-01
影响因子：
1.2
通讯作者：
Bowien, Botho
中科院分区：
文献类型：
--
作者：
Fricke, Wolfgang Florian;Kusian, Bernhard;Bowien, Botho
真养罗尔斯顿菌 H16 菌株是一种兼性化能自养、氢氧化细菌，属于β-变形菌门伯克霍尔德氏菌科。富养罗伯茨菌H16的基因组由两条染色体（Chr1、Chr2）和一个大质粒（pHG1）组成，因此显示出多复制子结构，这是迄今为止测序的伯克霍尔德氏菌科所有成员的特征。管家细胞功能的基因位于 Chr1。相比之下，富养罗伯茨菌 H16 的许多特征，例如在替代生活方式之间切换的能力和利用多种生长底物的能力，主要是在较小的复制子 Chr2 和 pHG1 上编码的。后者的复制子也与 Chr1 不同，它携带通常在质粒上发现的与repA相关的复制起点。通过多重序列比对和全复制子蛋白比较来研究来自不同伯克霍尔德氏菌科基因组的各个复制子之间的关系。虽然最大的复制子之间基因内容和顺序的强烈保守性表明有一个共同的祖先，但较小的复制子之间的相似性要低得多，这表明 Chr2 具有物种特异性起源。然而，在大多数情况下，大质粒不表现出任何分类学相关的相似性。基于比较研究的结果，提出了伯克霍尔德氏菌科多复制子基因组进化的假设。版权所有 (c) 2008 S. Karger AG，巴塞尔
Ralstonia eutropha strain H16 is a facultatively chemolithoautotrophic, hydrogen-oxidizing bacterium belonging to the family Burkholderiaceae of the Betaproteobacteria. The genome of R. eutropha H16 consists of two chromosomes (Chr1, Chr2) and one megaplasmid (pHG1), and thus shows a multireplicon architecture, which is characteristic for all members of the Burkholderiaceae sequenced so far. The genes for housekeeping cell functions are located on Chr1. In contrast, many characteristic traits of R. eutropha H16 such as the ability to switch between alternative lifestyles and to utilize a broad variety of growth substrates are primarily encoded on the smaller replicons Chr2 and pHG1. The latter replicons also differ from Chr1 by carrying a repA-associated origin of replication typically found on plasmids. Relationships between the individual replicons from various Burkholderiaceae genomes were studied by multiple sequence alignments and whole-replicon protein comparisons. While strong conservation of gene content and order among the largest replicons indicate a common ancestor, the resemblance between the smaller replicons is considerably lower, suggesting a species-specific origin of Chr2. The megaplasmids, however, in most cases do not show any taxonomically related similarities. Based on the results of the comparative studies, a hypothesis for the evolution of the multi- replicon genomes of the Burkholderiaceae is proposed. Copyright (c) 2008 S. Karger AG, Basel