Department of Genetics and Evolution, Federal University of Sao Carlos, Sao Carlos, Sao Paulo, Brazil.
Grupo de Investigación de Biología y Ecología de Artrópodos. Facultad de Ciencias., Universidad del Tolima, Tolima, Colombia.
PeerJ. 2022 Aug 29;10:e13120. doi: 10.7717/peerj.13120. eCollection 2022.
Virulence factors (VF) are bacteria-associated molecules that assist to colonize the host at the cellular level. Bacterial virulence is highly dynamic and specific pathogens have a broad array of VFs. The genus is gram-negative, microaerobic, flagellated, and mucus-inhabiting bacteria associated with gastrointestinal inflammation. To investigate about their pathogenicity, several species have been characterized and sequenced. Since the variability and possible origin of VF in the genus are not clear, our goal was to perform a comparative analysis of species in order to investigate VF variability and their evolutionary origin.
The complete genomes of 22 species available in NCBI were analyzed, using computational tools. We identifyed gain and loss events in VF genes, which were categorized in seven functional groups to determine their most parsimonious evolutionary origin. After verifying the annotation of all VF genes, a phylogeny from conserved VF organized by species according to gastric species (GHS) or enterohepatic (EHS) classification was obtained.
Gain and loss analysis of VF orthologous in ssp revealed the most possible evolutionary origin for each gene set. Microevolutionary events in urease and flagella genes were detected during the evolution of the genus. Our results pointed that acquisition of ureases and adherence genes and deletion of cytotoxins in some lineages, as well as variation in VF genes copy number, would be related to host adaptation during evolution of the genus. Our findings provided new insights about the genetic differences between GHS and EHS and their relationship with pathogenicity.
毒力因子（VF）是细菌相关分子，有助于在细胞水平上定植宿主。细菌的毒力具有高度的动态性，特定的病原体具有广泛的 VF。属是革兰氏阴性、微需氧、鞭毛和黏液栖息的细菌，与胃肠道炎症有关。为了研究它们的致病性，已经对几种 物种进行了特征描述和测序。由于属中 VF 的可变性和可能的起源尚不清楚，我们的目标是对 物种进行比较分析，以研究 VF 的变异性及其进化起源。
使用计算工具分析了 NCBI 中可用的 22 种 物种的完整基因组。我们鉴定了 VF 基因的增益和缺失事件，并将其分为七个功能组，以确定它们最简约的进化起源。在验证了所有 VF 基因的注释后，根据胃 物种（GHS）或肠肝（EHS）分类，根据 物种组织的保守 VF 构建了一个系统发育树。
对 ssp 的 VF 直系同源物的增益和缺失分析揭示了每个基因集最可能的进化起源。在属的进化过程中，检测到脲酶和鞭毛基因的微进化事件。我们的研究结果表明，在属的进化过程中，一些谱系获得了脲酶和黏附基因，而一些谱系则删除了细胞毒素，以及 VF 基因拷贝数的变化，这与宿主适应有关。我们的研究结果提供了关于 GHS 和 EHS 之间遗传差异及其与致病性关系的新见解。
