The PecT Repressor Coregulates Synthesis of Exopolysaccharides and Virulence Factors in <i>Erwinia chrysanthemi</i>

Condemine, Guy; Castillo, Arnaud; Passeri, Fabrice; Enard, Corine

doi:10.1094/mpmi.1999.12.1.45

Cited by 68 publications

(51 citation statements)

References 43 publications

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“…A variety of factors have been shown to influence the ability of D. dadantii 3937 to attack plant tissue, but pectinolytic enzymes are considered to be the major determinant of pathogenicity (41, 41a, 59a, 61). Additional factors that contribute to its pathogenicity are exopolysaccharide (8), lipopolysaccharide (53), siderophore-mediated iron transport systems (14), the type III secretion system encoded by the hrp gene cluster (5), antimicrobial peptides (18), motility (12), and proteins involved in resistance against plant defense mechanisms (12,33). The expression of these functions is regulated in a coordinated manner in response to different stimuli, such as the presence of pectic substances, acidic pH, iron, magnesium limitation, plant extract, and the presence of antimicrobial molecules.…”

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SlyA, a MarR Family Transcriptional Regulator, Is Essential for Virulence inDickeya dadantii3937

et al. 2009

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SlyA, a MarR family transcriptional regulator, controls an assortment of biological functions in several animal-pathogenic bacteria. In order to elucidate the functions of SlyA in the phytopathogen Dickeya dadantii (formerly Erwinia chrysanthemi) 3937, a slyA gene deletion mutant (denoted ⌬slyA) was constructed. The mutant exhibited increased sensitivity to sodium hypochlorite, the cationic antimicrobial peptide polymyxin B, and oxidative stress. The mutant showed reduced production of pectate lyase and exopolysaccharide and an inability to form a pellicle. The mutant lacking a functional slyA gene showed a significantly reduced ability to cause maceration of potato tubers. Accordingly, the mutant exhibited significantly reduced bacterial growth and failed to hyperinduce pectate lyase production in planta. Introduction of a plasmid containing slyA into the ⌬slyA mutant caused all of these phenotypes to recover to wild-type levels. These results suggest that SlyA plays an important role in virulence to plants by positively regulating the expression of multiple pathogenicityrelated traits of D. dadantii 3937.

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SlyA, a MarR Family Transcriptional Regulator, Is Essential for Virulence inDickeya dadantii3937

et al. 2009

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“…To test these hypotheses, an opgG eps double mutant strain was constructed by transduction. Exopolysaccharides are synthesized by the eps operon products (Condemine et al, 1999). While the opgG strain displayed a mucoid phenotype, the eps opgG strain restored a non-mucoid phenotype.…”

Section: Motility Is Not Restored In the Opgg Pecs Double Mutant Strainmentioning

confidence: 99%

Inactivation of pecS restores the virulence of mutants devoid of osmoregulated periplasmic glucans in the phytopathogenic bacterium Dickeya dadantii

2014

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Dickeya dadantii is a phytopathogenic enterobacterium that causes soft rot disease in a wide range of plant species. Maceration, an apparent symptom of the disease, is the result of the synthesis and secretion of a set of plant cell wall-degrading enzymes (PCWDEs), but many additional factors are required for full virulence. Among these, osmoregulated periplasmic glucans (OPGs) and the PecS transcriptional regulator are essential virulence factors. Several cellular functions are controlled by both OPGs and PecS. Strains devoid of OPGs display a pleiotropic phenotype including total loss of virulence, loss of motility and severe reduction in the synthesis of PCWDEs. PecS is one of the major regulators of virulence in D. dadantii, acting mainly as a repressor of various cellular functions including virulence, motility and synthesis of PCWDEs. The present study shows that inactivation of the pecS gene restored virulence in a D. dadantii strain devoid of OPGs, indicating that PecS cannot be de-repressed in strains devoid of OPGs.

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“…PecT also represses genes involved in motility and genes required for EPS synthesis (Table 1) (68, 86). An eps mutant is less efficient than the wild-type strain in initiating a maceration symptom, suggesting that production of EPS is required for the full virulence (86).…”

Section: Vol 69 2005mentioning

confidence: 99%

Detection of and Response to Signals Involved in Host-Microbe Interactions by Plant-Associated Bacteria

Brencic

Winans

2005

Microbiol Mol Biol Rev

337

208

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Diverse interactions between hosts and microbes are initiated by the detection of host-released chemical signals. Detection of these signals leads to altered patterns of gene expression that culminate in specific and adaptive changes in bacterial physiology that are required for these associations. This concept was first demonstrated for the members of the family Rhizobiaceae and was later found to apply to many other plant-associated bacteria as well as to microbes that colonize human and animal hosts. The family Rhizobiaceae includes various genera of rhizobia as well as species of Agrobacterium. Rhizobia are symbionts of legumes, which fix nitrogen within root nodules, while Agrobacterium tumefaciens is a pathogen that causes crown gall tumors on a wide variety of plants. The plant-released signals that are recognized by these bacteria are low-molecular-weight, diffusible molecules and are detected by the bacteria through specific receptor proteins. Similar phenomena are observed with other plant pathogens, including Pseudomonas syringae, Ralstonia solanacearum, and Erwinia spp., although here the signals and signal receptors are not as well defined. In some cases, nutritional conditions such as iron limitation or the lack of nitrogen sources seem to provide a significant cue. While much has been learned about the process of host detection over the past 20 years, our knowledge is far from being complete. The complex nature of the plant-microbe interactions makes it extremely challenging to gain a comprehensive picture of host detection in natural environments, and thus many signals and signal recognition systems remain to be described

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The PecT Repressor Coregulates Synthesis of Exopolysaccharides and Virulence Factors in Erwinia chrysanthemi

Cited by 68 publications

References 43 publications

SlyA, a MarR Family Transcriptional Regulator, Is Essential for Virulence inDickeya dadantii3937

SlyA, a MarR Family Transcriptional Regulator, Is Essential for Virulence inDickeya dadantii3937

Inactivation of pecS restores the virulence of mutants devoid of osmoregulated periplasmic glucans in the phytopathogenic bacterium Dickeya dadantii

Detection of and Response to Signals Involved in Host-Microbe Interactions by Plant-Associated Bacteria

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