Baraúna Rafael A, Ramos Rommel T J, Veras Adonney A O, Pinheiro Kenny C, Benevides Leandro J, Viana Marcus V C, Guimarães Luís C, Edman Judy M, Spier Sharon J, Azevedo Vasco, Silva Artur
Laboratory of Genomics and Bioinformatics, Center of Genomics and Systems Biology, Institute of Biological Sciences, Federal University of Pará, Belém, Pará, Brazil.
Laboratory of Cellular and Molecular Genetics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
PLoS One. 2017 Jan 26;12(1):e0170676. doi: 10.1371/journal.pone.0170676. eCollection 2017.
Seven genomes of Corynebacterium pseudotuberculosis biovar equi were sequenced on the Ion Torrent PGM platform, generating high-quality scaffolds over 2.35 Mbp. This bacterium is the causative agent of disease known as "pigeon fever" which commonly affects horses worldwide. The pangenome of biovar equi was calculated and two phylogenomic approaches were used to identify clustering patterns within Corynebacterium genus. Furthermore, other comparative analyses were performed including the prediction of genomic islands and prophages, and SNP-based phylogeny. In the phylogenomic tree, C. pseudotuberculosis was divided into two distinct clades, one formed by nitrate non-reducing species (biovar ovis) and another formed by nitrate-reducing species (biovar equi). In the latter group, the strains isolated from California were more related to each other, while the strains CIP 52.97 and 1/06-A formed the outermost clade of the biovar equi. A total of 1,355 core genes were identified, corresponding to 42.5% of the pangenome. This pangenome has one of the smallest core genomes described in the literature, suggesting a high genetic variability of biovar equi of C. pseudotuberculosis. The analysis of the similarity between the resistance islands identified a higher proximity between the strains that caused more severe infectious conditions (infection in the internal organs). Pathogenicity islands were largely conserved between strains. Several genes that modulate the pathogenicity of C. pseudotuberculosis were described including peptidases, recombination enzymes, micoside synthesis enzymes, bacteriocins with antimicrobial activity and several others. Finally, no genotypic differences were observed between the strains that caused the three different types of infection (external abscess formation, infection with abscess formation in the internal organs, and ulcerative lymphangitis). Instead, it was noted that there is a higher phenetic correlation between strains isolated at California compared to the other strains. Additionally, high variability of resistance islands suggests gene acquisition through several events of horizontal gene transfer.
在Ion Torrent PGM平台上对7个马伪结核棒状杆菌生物变种的基因组进行了测序，生成了超过2.35 Mbp的高质量支架。这种细菌是被称为“鸽瘟”疾病的病原体，该病在全球范围内普遍影响马匹。计算了生物变种的泛基因组，并使用两种系统发育基因组学方法来确定棒状杆菌属内的聚类模式。此外，还进行了其他比较分析，包括基因组岛和原噬菌体的预测以及基于单核苷酸多态性的系统发育分析。在系统发育基因组树中，伪结核棒状杆菌被分为两个不同的进化枝，一个由硝酸盐不还原菌种（生物变种ovis）形成，另一个由硝酸盐还原菌种（生物变种equi）形成。在后一组中，从加利福尼亚分离的菌株彼此之间的关系更为密切，而菌株CIP 52.97和1/06 - A形成了生物变种equi的最外层进化枝。总共鉴定出1355个核心基因，占泛基因组的42.5%。这个泛基因组具有文献中描述的最小核心基因组之一，表明伪结核棒状杆菌生物变种equi具有高度的遗传变异性。对耐药岛之间相似性的分析确定，导致更严重感染状况（内脏感染）的菌株之间具有更高的相似性。致病岛在菌株之间基本保守。描述了几个调节伪结核棒状杆菌致病性的基因，包括肽酶、重组酶、微苷合成酶、具有抗菌活性的细菌素等。最后，在导致三种不同类型感染（外部脓肿形成、内脏脓肿形成感染和溃疡性淋巴管炎）的菌株之间未观察到基因型差异。相反，注意到与其他菌株相比，在加利福尼亚分离的菌株之间具有更高的表型相关性。此外，耐药岛的高度变异性表明通过多次水平基因转移事件获得了基因。
