Salmonella bongori Provides Insights into the Evolution of the Salmonellae
File(s)
Author(s)
Type
Journal Article
Abstract
The genus Salmonella contains two species, S. bongori and S. enterica. Compared to the well-studied S. enterica there is a marked lack of information regarding the genetic makeup and diversity of S. bongori. S. bongori has been found predominantly associated with cold-blooded animals, but it can infect humans. To define the phylogeny of this species, and compare it to S. enterica, we have sequenced 28 isolates representing most of the known diversity of S. bongori. This cross-species analysis allowed us to confidently differentiate ancestral functions from those acquired following speciation, which include both metabolic and virulence-associated capacities. We show that, although S. bongori inherited a basic set of Salmonella common virulence functions, it has subsequently elaborated on this in a different direction to S. enterica. It is an established feature of S. enterica evolution that the acquisition of the type III secretion systems (T3SS-1 and T3SS-2) has been followed by the sequential acquisition of genes encoding secreted targets, termed effectors proteins. We show that this is also true of S. bongori, which has acquired an array of novel effector proteins (sboA-L). All but two of these effectors have no significant S. enterica homologues and instead are highly similar to those found in enteropathogenic Escherichia coli (EPEC). Remarkably, SboH is found to be a chimeric effector protein, encoded by a fusion of the T3SS-1 effector gene sopA and a gene highly similar to the EPEC effector nleH from enteropathogenic E. coli. We demonstrate that representatives of these new effectors are translocated and that SboH, similarly to NleH, blocks intrinsic apoptotic pathways while being targeted to the mitochondria by the SopA part of the fusion. This work suggests that S. bongori has inherited the ancestral Salmonella virulence gene set, but has adapted by incorporating virulence determinants that resemble those employed by EPEC.
Date Issued
2011-08-18
Date Acceptance
2011-06-21
Citation
PLOS Pathogens, 2011, 7 (8)
ISSN
1553-7366
Publisher
Public Library of Science
Journal / Book Title
PLOS Pathogens
Volume
7
Issue
8
Copyright Statement
© 2011 Fookes et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
License URL
Subjects
Science & Technology
Life Sciences & Biomedicine
Microbiology
Parasitology
Virology
MICROBIOLOGY
PARASITOLOGY
VIROLOGY
ENTERICA SEROVAR TYPHIMURIUM
PATHOGENICITY ISLAND 2
COMPLETE GENOME SEQUENCE
ESCHERICHIA-COLI K-12
III SECRETION SYSTEM
KLEBSIELLA-PNEUMONIAE
MICROARRAY ANALYSIS
UREIDOGLYCOLLATE LYASE
ANTIBIOTIC-RESISTANCE
ENCODED EFFECTOR
Animals
Biological Evolution
Enteropathogenic Escherichia coli
Genes, Bacterial
Genomic Islands
Humans
Phylogeny
Salmonella
Salmonella enterica
Sequence Analysis, DNA
Translocation, Genetic
Virulence
Virulence Factors
0605 Microbiology
1107 Immunology
1108 Medical Microbiology
Publication Status
Published
Article Number
e1002191