The two‐component system <scp>CpxAR</scp> is essential for virulence in the phytopathogen bacteria <scp><i>D</i></scp><i>ickeya dadantii</i> <scp>EC</scp>3937

Bontemps­-Gallo, Sébastien; Madec, Edwige; Lacroix, Jean-Marie

doi:10.1111/1462-2920.12874

Cited by 26 publications

(22 citation statements)

References 46 publications

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“…The hostile conditions in the apoplast affect bacterial envelope integrity. These alterations are sensed by the CpxAR system that protects the bacterium from plant defenses and down-regulates both CWDE production and motility (Bontemps-Gallo et al, 2015). During this early phase, the GacAS system is inactive due to the low concentration of organic acids.…”

Section: Molecular Dialog Between Phytopathogens and Plants 1707mentioning

confidence: 99%

Plant–phytopathogen interactions: bacterial responses to environmental and plant stimuli

Léonard

Hommais

Nasser

et al. 2017

Environmental Microbiology

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Summary Plant pathogenic bacteria attack numerous agricultural crops, causing devastating effects on plant productivity and yield. They survive in diverse environments, both in plants, as pathogens, and also outside their hosts as saprophytes. Hence, they are confronted with numerous changing environmental parameters. During infection, plant pathogens have to deal with stressful conditions, such as acidic, oxidative and osmotic stresses; anaerobiosis; plant defenses; and contact with antimicrobial compounds. These adverse conditions can reduce bacterial survival and compromise disease initiation and propagation. Successful bacterial plant pathogens must detect potential hosts and also coordinate their possibly conflicting programs for survival and virulence. Consequently, these bacteria have a strong and finely tuned capacity for sensing and responding to environmental and plant stimuli. This review summarizes our current knowledge of the signals and genetic circuits that affect survival and virulence factor expression in three important and well‐studied plant pathogenic bacteria with wide host ranges and the capacity for long‐term environmental survival. These are: Ralstonia solanacerarum, a vascular pathogen that causes wilt disease; Agrobacterium tumefaciens, a biotrophic tumorigenic pathogen responsible for crown gall disease and Dickeya, a brute force apoplastic pathogen responsible for soft‐rot disease.

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Section: Molecular Dialog Between Phytopathogens and Plants 1707mentioning

confidence: 99%

Plant–phytopathogen interactions: bacterial responses to environmental and plant stimuli

Léonard

Hommais

Nasser

et al. 2017

Environmental Microbiology

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“…Given that the EHEC cpxA mutant showed diminished expression of LEE genes (Figure 5A , Table 3 ) we sought to investigate the role of the CpxRA TCS in EHEC's virulence in the Galleria mellonella larvae model. This model has been employed to measure virulence of Salmonella , EPEC, and other enteric and non-enteric pathogens (O'Loughlin et al, 2010 ; Debnath et al, 2013 ; Bontemps-Gallo et al, 2015 ; De la Cruz et al, 2015 ; Thomassin et al, 2015 ). We compared the ability of EHEC strains (wild-type vs. mutants) to kill G. mellonella larvae.…”

Section: Resultsmentioning

confidence: 99%

“…A growing number of studies implicate the CpxRA TCS in the virulence of numerous Gram-negative bacteria (O'Loughlin et al, 2010 ; Debnath et al, 2013 ; Bontemps-Gallo et al, 2015 ; De la Cruz et al, 2015 ; Thomassin et al, 2015 ). The present study describes the importance of the CpxA sensor kinase in the regulation of virulence of EHEC by modulating LEE expression.…”

Section: Discussionmentioning

confidence: 99%

The Two-Component System CpxRA Negatively Regulates the Locus of Enterocyte Effacement of Enterohemorrhagic Escherichia coli Involving σ32 and Lon protease

Cruz

Morgan

Ares

et al. 2016

Front. Cell. Infect. Microbiol.

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Enterohemorrhagic Escherichia coli (EHEC) is a significant cause of serious human gastrointestinal disease worldwide. EHEC strains contain a pathogenicity island called the locus of enterocyte effacement (LEE), which encodes virulence factors responsible for damaging the gut mucosa. The Cpx envelope stress response of E. coli is controlled by a two-component system (TCS) consisting of a sensor histidine kinase (CpxA) and a cytoplasmic response regulator (CpxR). In this study, we investigated the role of CpxRA in the expression of LEE-encoded virulence factors of EHEC. We found that a mutation in cpxA significantly affected adherence of EHEC to human epithelial cells. Analysis of this mutant revealed the presence of high levels of CpxR which repressed transcription of grlA and ler, the main positive virulence regulators of the LEE, and influenced negatively the production of the type 3 secretion system–associated EspABD translocator proteins. It is known that CpxR activates rpoH (Sigma factor 32), which in turns activates transcription of the lon protease gene. We found that transcription levels of ler and grlA were significantly increased in the lon and cpxA lon mutants suggesting that lon is involved in down-regulating LEE genes. In addition, the Galleria mellonella model of infection was used to analyze the effect of the loss of the cpx and lon genes in EHEC's ability to kill the larvae. We found that the cpxA mutant was significantly deficient at killing the larvae however, the cpxA lon mutant which overexpresses LEE genes in vitro, was unable to kill the larvae, suggesting that virulence in the G. mellonella model is T3SS independent and that CpxA modulates virulence through a yet unknown EHEC-specific factor. Our data provides new insights and broadens our scope into the complex regulatory network of the LEE in which the CpxA sensor kinase plays an important role in a cascade involving both global and virulence regulators.

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“…With the ability to repress a large array of virulence determinants in several different bacterial pathogens, it is not surprising that genetically activated Cpx signaling results in virulence attenuation of bacteria in various in vivo infection models (Humphreys et al, 2004 ; Herbert Tran and Goodrich-Blair, 2009 ; Spinola et al, 2010 ; Leuko and Raivio, 2012 ; Debnath et al, 2013 ; Bontemps-Gallo et al, 2015 ; Thomassin et al, 2015 ). Yet, it remains to be seen if a fully intact Cpx system is actually activated in the in vivo environment of a eukaryotic host.…”

Section: Survival In Noxious Environmentsmentioning

confidence: 99%

Environmental Regulation of Yersinia Pathophysiology

Chen

Thompson

Francis

2016

Front. Cell. Infect. Microbiol.

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Hallmarks of Yersinia pathogenesis include the ability to form biofilms on surfaces, the ability to establish close contact with eukaryotic target cells and the ability to hijack eukaryotic cell signaling and take over control of strategic cellular processes. Many of these virulence traits are already well-described. However, of equal importance is knowledge of both confined and global regulatory networks that collaborate together to dictate spatial and temporal control of virulence gene expression. This review has the purpose to incorporate historical observations with new discoveries to provide molecular insight into how some of these regulatory mechanisms respond rapidly to environmental flux to govern tight control of virulence gene expression by pathogenic Yersinia.

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The two‐component system CpxAR is essential for virulence in the phytopathogen bacteria Dickeya dadantii EC3937

Cited by 26 publications

References 46 publications

Plant–phytopathogen interactions: bacterial responses to environmental and plant stimuli

Plant–phytopathogen interactions: bacterial responses to environmental and plant stimuli

The Two-Component System CpxRA Negatively Regulates the Locus of Enterocyte Effacement of Enterohemorrhagic Escherichia coli Involving σ32 and Lon protease

Environmental Regulation of Yersinia Pathophysiology

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