Core and Accessory Genome Analysis of Vibrio mimicus.

Iliana Guardiola-Avila,Fernando González-Candelas,Manuel Zúñiga-Cabrera,Evelia Acedo-Félix,Bruno Gomez-Gil,Leonor Sánchez-Busó,Lorena Noriega-Orozco

doi:10.3390/microorganisms9010191

Abstract

Vibrio mimicus is an emerging pathogen, mainly associated with contaminated seafood consumption. However, little is known about its evolution, biodiversity, and pathogenic potential. This study analyzes the pan-, core, and accessory genomes of nine V. mimicus strains. The core genome yielded 2424 genes in chromosome I (ChI) and 822 genes in chromosome II (ChII), with an accessory genome comprising an average of 10.9% of the whole genome for ChI and 29% for ChII. Core genome phylogenetic trees were obtained, and V. mimicus ATCC-33654 strain was the closest to the outgroup in both chromosomes. Additionally, a phylogenetic study of eight conserved genes (ftsZ, gapA, gyrB, topA, rpoA, recA, mreB, and pyrH), including Vibrio cholerae, Vibrio parilis, Vibrio metoecus, and Vibrio caribbenthicus, clearly showed clade differentiation. The main virulence genes found in ChI corresponded with type I secretion proteins, extracellular components, flagellar proteins, and potential regulators, while, in ChII, the main categories were type-I secretion proteins, chemotaxis proteins, and antibiotic resistance proteins. The accessory genome was characterized by the presence of mobile elements and toxin encoding genes in both chromosomes. Based on the genome atlas, it was possible to characterize differential regions between strains. The pan-genome of V. mimicus encompassed 3539 genes for ChI and 2355 genes for ChII. These results give us an insight into the virulence and gene content of V. mimicus, as well as constitute the first approach to its diversity.

Highlights

The genus Vibrio contains more than 100 species typically isolated from aquatic environments, and several of them may cause infections in humans and animals [1,2]
The comparative genome analysis of Vibrio metoecus (RC341) and Vibrio parilis (RC586), previously characterized as environmental non-pathogenic variants of V. cholerae, demonstrated that V. metoecus evolved from V. cholera/V. mimicus lineages, while V. parilis from an ancestral V. mimicus lineage [16,18,19]
The analysis of the pan-genome resulted in 3539 genes for chromosome I (ChI) and 2355 genes for chromosome II (ChII)

Summary

Introduction

The genus Vibrio contains more than 100 species typically isolated from aquatic environments, and several of them may cause infections in humans and animals [1,2]. V. mimicus and V. cholerae share many phenotypic characteristics and virulence genes, such as cholera toxin (Ctx), toxin-coregulated pilus, and pathogenicity islands, among others [13] This makes V. cholerae an appropriate outgroup when conducting evolutionary studies of V. mimicus [3,9,17]. The comparative genome analysis of Vibrio metoecus (RC341) and Vibrio parilis (RC586), previously characterized as environmental non-pathogenic variants of V. cholerae, demonstrated that V. metoecus evolved from V. cholera/V. mimicus lineages, while V. parilis from an ancestral V. mimicus lineage [16,18,19] This type of information contributes to the understanding of Vibrio species diversity [10]

Methods

Results

Conclusion