Whole genome investigation of a divergent clade of the pathogen Streptococcus suis.
Whole genome investigation of a divergent clade of the pathogen Streptococcus suis.
复制标题
病原体链球菌链球菌发散进化枝的整个基因组研究。
DOI：
10.3389/fmicb.2015.01191
复制
发表时间：
2015
影响因子：
5.2
通讯作者：
Maskell DJ
中科院分区：
文献类型：
--
作者：
Baig A;Weinert LA;Peters SE;Howell KJ;Chaudhuri RR;Wang J;Holden MT;Parkhill J;Langford PR;Rycroft AN;Wren BW;Tucker AW;Maskell DJ
猪链球菌是一种主要的猪和人畜共患病原体，给养猪业造成重大经济损失，并造成越来越多的人类病例。多株S.猪显示出显著的基因组多样性。在这里，我们报告了9个猪分离株的全基因组序列分析，这些猪分离株引起典型的猪链球菌病。具有猪链球菌的表型特征。但它们的基因组与许多其他猪链球菌的基因组不同。猪分离株。从不同基因组预测的蛋白质序列与正常S。suis将核心基因组的大小从793个减少到只有397个基因。如果对减少的核心基因和MLST等位基因进行系统发育分析，则分歧是明显的。基于某些其他基因（16 S rRNA，sodA，recN和cpn 60）的系统发育并没有显示出所有分离株的分歧，这表明一些分歧分离株与正常的S。这些基因。事实上，有证据表明，最近的重组之间的分歧和正常的S。猪的基因组包含397个核心基因中的249个。此外，基于16 S rRNA基因和132个基因的系统发育分析表明，分歧菌株和更广泛的链球菌属的代表之间的保守性，分歧菌株更接近于S。猪。9个分离株中有6个具有S.具有囊膜基因序列变异的猪样囊膜区域，但其余三个没有离散的囊膜基因座。在正常血吸虫中，大多数（40/70）与毒力相关的基因。在不同的基因组中存在猪。总体而言，分歧的分离物扩展了目前的S。猪链球菌与正常猪链球菌的表型相似，基因交换量大。suis没有提供足够的证据将这些分离物指定为一个新的种或亚种。此外，采样和全基因组分析更多的分离物是必要的，以了解物种的多样性。
Streptococcus suis is a major porcine and zoonotic pathogen responsible for significant economic losses in the pig industry and an increasing number of human cases. Multiple isolates of S. suis show marked genomic diversity. Here, we report the analysis of whole genome sequences of nine pig isolates that caused disease typical of S. suis and had phenotypic characteristics of S. suis, but their genomes were divergent from those of many other S. suis isolates. Comparison of protein sequences predicted from divergent genomes with those from normal S. suis reduced the size of core genome from 793 to only 397 genes. Divergence was clear if phylogenetic analysis was performed on reduced core genes and MLST alleles. Phylogenies based on certain other genes (16S rRNA, sodA, recN, and cpn60) did not show divergence for all isolates, suggesting recombination between some divergent isolates with normal S. suis for these genes. Indeed, there is evidence of recent recombination between the divergent and normal S. suis genomes for 249 of 397 core genes. In addition, phylogenetic analysis based on the 16S rRNA gene and 132 genes that were conserved between the divergent isolates and representatives of the broader Streptococcus genus showed that divergent isolates were more closely related to S. suis. Six out of nine divergent isolates possessed a S. suis-like capsule region with variation in capsular gene sequences but the remaining three did not have a discrete capsule locus. The majority (40/70), of virulence-associated genes in normal S. suis were present in the divergent genomes. Overall, the divergent isolates extend the current diversity of S. suis species but the phenotypic similarities and the large amount of gene exchange with normal S. suis gives insufficient evidence to assign these isolates to a new species or subspecies. Further, sampling and whole genome analysis of more isolates is warranted to understand the diversity of the species.