title: RpoS (sigma-S) controls expression of rsmA, a global regulator of secondary metabolites, harpin, and extracellular proteins in Erwinia carotovora.
abstract: RpoS (sigma-S or sigma-38) controls a large array of genes that are expressed during stationary phase and under various stress conditions in Escherichia coli and other bacteria. We document here that plant pathogenic and epiphytic Erwinia species, such as E. amylovora; E. carotovora subsp. atroseptica, betavasculorum, and carotovora; E. chrysanthemi; E. herbicola; E. rhapontici; and E. stewartii, possess rpoS genes and produce the alternate sigma factor. We show that rpoS transcription in E. carotovora subsp. carotovora is driven from a major promoter which resides within the nlpD gene located upstream of rpoS as in E. coli. RpoS- E. carotovora subsp. carotovoa strain AC5061, constructed by marker exchange, is more sensitive to hydrogen peroxide, carbon starvation, and acidic pH than its RpoS+ parent strain, AC5006. The basal levels of extracellular pectate lyase, polygalacturonase, and cellulase as well as those of transcripts of E. carotovora subsp. carotovora hrpN (hrpNEcc), the gene for the elicitor of the hypersensitive reaction, are higher in the RpoS- strain than in the RpoS+ parent. Likewise, compared to AC5006, AC5061 causes more extensive maceration of celery petioles. Our findings with the RpoS- mutant and strains carrying multiple copies rpoS+ DNA reveal that rpoS positively controls rsmA expression. We also present evidence that supports the hypothesis that the RpoS effect on extracellular enzyme levels, hrpNEcc expression, and virulence manifests itself by the modulation of rsmA expression.
authors.affiliation: Department of Plant Pathology, University of Missouri, Columbia, Missouri 65211, USA.
authors.forename: A
authors.initials: A
authors.lastname: Mukherjee
authors.forename: Y
authors.initials: Y
authors.lastname: Cui
authors.forename: W
authors.initials: W
authors.lastname: Ma
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.forename: A
authors.initials: A
authors.lastname: Ishihama
authors.forename: A
authors.initials: A
authors.lastname: Eisenstark
authors.forename: A K
authors.initials: AK
authors.lastname: Chatterjee
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D001483:Base Sequence; D004268:DNA-Binding Proteins; D012321:DNA-Directed RNA Polymerases / Q000235:genetics*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D016973:Pectobacterium carotovorum / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D051877:RNA Polymerase Sigma 54; D016601:RNA-Binding Proteins; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D012808:Sigma Factor / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; C095468:RsmA protein, Erwinia carotovora; D012808:Sigma Factor; C075462:harpin protein, Erwinia amylovora; C497751:rpoN protein, E coli; C069567:sigma factor KatF protein, Bacteria; C087295:HrpZ protein, Pseudomonas syringae; D012321:DNA-Directed RNA Polymerases; D051877:RNA Polymerase Sigma 54