title: A metabolic regulator modulates virulence and quorum sensing signal production in Pectobacterium atrosepticum.
abstract: Plant cell wall-degrading enzymes (PCWDE) are key virulence determinants in the pathogenesis of the potato pathogen Pectobacterium atrosepticum. In this study, we report the impact on virulence of a transposon insertion mutation in the metJ gene that codes for the repressor of the methionine biosynthesis regulon. In a mutant strain defective for the small regulatory RNA rsmB, PCWDE are not produced and virulence in potato tubers is almost totally abolished. However, when the metJ gene is disrupted in this background, the rsmB(-) phenotype is suppressed and virulence and PCWDE production are restored. Additionally, when metJ is disrupted, production of the quorum-sensing signal, N-(3-oxohexanoyl)-homoserine lactone, is increased. The metJ mutant strains showed pleiotropic transcriptional impacts affecting approximately a quarter of the genome. Genes involved in methionine biosynthesis were most highly upregulated but many virulence-associated transcripts were also upregulated. This is the first report of the impact of the MetJ repressor on virulence in bacteria.
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge, UK.
authors.forename: Marion F
authors.initials: MF
authors.lastname: Cubitt
authors.forename: Peter E
authors.initials: PE
authors.lastname: Hedley
authors.forename: Neil R
authors.initials: NR
authors.lastname: Williamson
authors.forename: Jenny A
authors.initials: JA
authors.lastname: Morris
authors.forename: Emma
authors.initials: E
authors.lastname: Campbell
authors.forename: Ian K
authors.initials: IK
authors.lastname: Toth
authors.forename: George P C
authors.initials: GP
authors.lastname: Salmond
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002473:Cell Wall / Q000378:metabolism; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics*; D008715:Methionine / Q000378:metabolism; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D059372:Nucleotide Motifs; D020411:Oligonucleotide Array Sequence Analysis; D044043:Pectobacterium / Q000201:enzymology / Q000235:genetics* / Q000472:pathogenicity / Q000502:physiology; D010447:Peptide Hydrolases / Q000378:metabolism; D010641:Phenotype; D035281:Plant Tubers / Q000382:microbiology; D011133:Polysaccharide-Lyases / Q000378:metabolism; D053038:Quorum Sensing / Q000235:genetics*; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D015398:Signal Transduction; D011198:Solanum tuberosum / Q000382:microbiology*; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D012097:Repressor Proteins; C060486:methionine repressor protein, Bacteria; C088386:homoserine lactone; D008715:Methionine; D010447:Peptide Hydrolases; D011133:Polysaccharide-Lyases; C023911:pectate lyase; D015107:4-Butyrolactone