青枯雷尔氏菌GMI1000二分体基因组中的简单序列重复和组成偏倚
Simple sequence repeats and compositional bias in the bipartite Ralstonia solanacearum GMI1000 genome.
作者信息
Coenye Tom, Vandamme Peter
机构信息
Laboratorium voor Microbiologie, Ghent University,K,L, Ledeganckstraat 35, B-9000 Gent, Belgium.
出版信息
BMC Genomics. 2003 Mar 17;4(1):10. doi: 10.1186/1471-2164-4-10.
BACKGROUND
Ralstonia solanacearum is an important plant pathogen. The genome of R. solananearum GMI1000 is organised into two replicons (a 3.7-Mb chromosome and a 2.1-Mb megaplasmid) and this bipartite genome structure is characteristic for most R. solanacearum strains. To determine whether the megaplasmid was acquired via recent horizontal gene transfer or is part of an ancestral single chromosome, we compared the abundance, distribution and composition of simple sequence repeats (SSRs) between both replicons and also compared the respective compositional biases.
RESULTS
Our data show that both replicons are very similar in respect to distribution and composition of SSRs and presence of compositional biases. Minor variations in SSR and compositional biases observed may be attributable to minor differences in gene expression and regulation of gene expression or can be attributed to the small sample numbers observed.
CONCLUSIONS
The observed similarities indicate that both replicons have shared a similar evolutionary history and thus suggest that the megaplasmid was not recently acquired from other organisms by lateral gene transfer but is a part of an ancestral R. solanacearum chromosome.
背景
青枯雷尔氏菌是一种重要的植物病原体。青枯雷尔氏菌GMI1000的基因组由两个复制子组成（一条3.7兆碱基对的染色体和一条2.1兆碱基对的大质粒），这种二分体基因组结构是大多数青枯雷尔氏菌菌株的特征。为了确定该大质粒是通过近期的水平基因转移获得的，还是祖先单染色体的一部分，我们比较了两个复制子之间简单序列重复（SSR）的丰度、分布和组成，还比较了各自的组成偏向性。
结果
我们的数据表明，两个复制子在SSR的分布和组成以及组成偏向性的存在方面非常相似。观察到的SSR和组成偏向性的微小差异可能归因于基因表达和基因表达调控的微小差异，或者可归因于观察到的样本数量较少。
结论
观察到的相似性表明两个复制子有着相似的进化历史，因此表明该大质粒并非近期通过侧向基因转移从其他生物体获得，而是青枯雷尔氏菌祖先染色体的一部分。
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