Expanded linkage map of <i>Erwinia chrysanthemi</i> strain 3937

Hugouvieux‐Cotte‐Pattat, Nicole; Reverchon, Sylvie; Robert‐Baudouy, Janine

doi:10.1111/j.1365-2958.1989.tb00204.x

Cited by 43 publications

(23 citation statements)

References 31 publications

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“…Using the opgG500::uidA-kan fusion, the Kan r marker cotransferred at 4% with ade-377, 10% with ogl, and 96% with ura-2. Thus, the opgGH locus is located very near the ura-2 marker on the E. chrysanthemi chromosome (17). In addition, the auxotrophy of the ura-2 mutant is complemented by the four pyrC ϩ R-prime plasmids isolated above, strongly suggesting that ura-2 is a mutation affecting the pyrC gene of E. chrysanthemi.…”

Section: Resultsmentioning

confidence: 79%

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Osmoregulated Periplasmic Glucan Synthesis Is Required for Erwinia chrysanthemi Pathogenicity

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Altabe

Hugouvieux‐Cotte‐Pattat

et al. 2001

J Bacteriol

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Erwinia chrysanthemi is a phytopathogenic enterobacterium causing soft rot disease in a wide range of plants. Osmoregulated periplasmic glucans (OPGs) are intrinsic components of the gram-negative bacterial envelope. We cloned the opgGH operon of E. chrysanthemi, encoding proteins involved in the glucose backbone synthesis of OPGs, by complementation of the homologous locus mdoGH of Escherichia coli. OpgG and OpgH show a high level of similarity with MdoG and MdoH, respectively, and mutations in the opgG or opgH gene abolish OPG synthesis. The opg mutants exhibit a pleiotropic phenotype, including overproduction of exopolysaccharides, reduced motility, bile salt hypersensitivity, reduced protease, cellulase, and pectate lyase production, and complete loss of virulence. Coinoculation experiments support the conclusion that OPGs present in the periplasmic space of the bacteria are necessary for growth in the plant host.Osmoregulated periplasmic glucans (OPGs) are a family of oligosaccharides found in the periplasmic space of gram-negative bacteria. Their two common features are the presence of glucose as the sole constituent sugar and their increased level in media of low osmolarity (5).Members of the family Enterobacteriaceae and related bacteria synthesize a family of linear and branched OPGs that are variously substituted. The linear backbone is constituted by glucose units joined by ␤,1-2 linkages, and the branches are made of one glucose unit linked to the main chain by a ␤,1-6 linkage. In Escherichia coli, the backbone, containing 7 to 13 glucose units, is substituted with phosphoglycerol, phosphoethanolamine, and succinyl residues (19). In Erwinia chrysanthemi, the backbone contains 5 to 12 glucose units substituted with succinyl and acetyl residues (9), and in Pseudomonas syringae, the backbone, consisting of 6 to 13 glucose units, is not substituted (38). In E. coli, the OPG backbone is synthesized by the products of the mdoGH operon located in the vicinity of pyrC, a gene involved in the biosynthesis of uracil (6). In this bacterium, the defect in OPG synthesis does not confer an easily selectable phenotype in laboratory conditions. Thus, the mdoGH locus was cloned using the linked selectable genetic marker pyrC (23).Many factors are involved in the virulence of pathogenic bacteria, and OPGs appear to be among them. In P. syringae pv. syringae, the causal agent of brown spot disease of the common bean (Phaseolus vulgaris), the hrpM mutant, obtained after transposon mutagenesis, was isolated because it failed to incite disease on the host plant and to cause the hypersensitive reaction on a non-host plant such as tobacco (29). The hrpM mutant does not synthesize OPGs, and the hrpM locus complements the OPG synthesis defect of the mdoH200::Tn10 mutant of E. coli. The amino acid sequences of HrpM and MdoH are 75.5% identical and 87.5% similar (25). More recently, a transposon insertion in a gene similar to hrpM/mdoH was isolated because it severely reduces the virulence in Pseudomonas aeruginosa PA14, an opp...

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Section: Resultsmentioning

confidence: 79%

“…We decided to use the selectable marker pyrC, located 13 kb downstream from the mdoGH locus in E. coli. Despite some important genomic rearrangements, the genetic organization of several genomic regions is quite similar in E. coli and E. chrysanthemi (17).…”

Section: Resultsmentioning

confidence: 99%

Osmoregulated Periplasmic Glucan Synthesis Is Required for Erwinia chrysanthemi Pathogenicity

Page

Altabe

Hugouvieux‐Cotte‐Pattat

et al. 2001

J Bacteriol

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“…These genes are organized in two clusters, pelADE and pelBC. PelA, PelD, and PelE are closely related, as are PelB and PelC, suggesting that recent gene duplications have occurred (225,479). Each pel gene, however, is transcribed from its own promoter, and no single pel gene is essential for virulence (29,412).…”

Section: Production Of Pectinolytic Enzymes By Soft Rot Erwiniasmentioning

confidence: 99%

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

Brencic

Winans

2005

Microbiol Mol Biol Rev

339

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 genes encoding the major PLs are arranged in two clusters on the bacterial chromosome. One cluster contains the pelB and pelC genes, and the other contains the pelA, pelD, and pelE genes (17). Each gene constitutes an independent transcriptional unit (36).…”

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Regulation of pelZ, a gene of the pelB-pelC cluster encoding a new pectate lyase of Erwinia chrysanthemi 3937

Pissavin¹,

Robert‐Baudouy²,

Hugouvieux‐Cotte‐Pattat³

1996

J Bacteriol

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The phytopathogenic enterobacterium Erwinia chrysanthemi 3937 produces five major and several secondary endo-pectate lyases encoded by the pel genes. Most of these genes are arranged in clusters on the bacterial chromosome. The genomic region surrounding the pelB-pelC cluster was supposed to be involved in the regulation of PelB and PelC synthesis. We demonstrated that the variation of pelB expression resulted from the titration of a regulatory protein by the gene adjacent to pelC. This gene was renamed pelZ since it encodes a protein of 420 amino acids with an endo-pectate lyase activity. Regulation of pelZ expression was investigated by using transcriptional fusions and a study of mRNA synthesis. Its transcription depends on different environmental conditions. It is induced in planta and in the presence of pectic catabolite products. This induction seems to be partially mediated by the KdgR protein but does not result from a direct interaction of KdgR with the pelZ 5 region. The transcription of pelZ leads to the synthesis of a monocistronic mRNA. However, the synthesis of a polycistronic mRNA from the pelC promoter, regulated by KdgR, is responsible for increased production of PelZ under inducing conditions. pelZ transcription is also controlled by pecT, which regulates some other pel genes, but it is independent of the pecS regulatory locus. The pelZ gene appears to be widespread in different strains of E. chrysanthemi. Moreover, a gene homologous to pelZ exists in Erwinia carotovora subsp. atroseptica adjacent to the cluster containing the pectate lyase-encoding genes pel1, pel2, and pel3. This conservation could reflect a significant role of PelZ in the pectinolytic system of Erwiniae. We showed pelZ is not a predominant virulence factor of E. chrysanthemi but is involved in host specificity.

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Expanded linkage map of Erwinia chrysanthemi strain 3937

Cited by 43 publications

References 31 publications

Osmoregulated Periplasmic Glucan Synthesis Is Required for Erwinia chrysanthemi Pathogenicity

Osmoregulated Periplasmic Glucan Synthesis Is Required for Erwinia chrysanthemi Pathogenicity

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

Regulation of pelZ, a gene of the pelB-pelC cluster encoding a new pectate lyase of Erwinia chrysanthemi 3937

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