title: Amplification of the housekeeping sigma factor in Pseudomonas fluorescens CHA0 enhances antibiotic production and improves biocontrol abilities.
abstract: Pseudomonas fluorescens CHA0 produces a variety of secondary metabolites, in particular the antibiotics pyoluteorin and 2,4-diacetylphloroglucinol, and protects various plants from diseases caused by soilborne pathogenic fungi. The rpoD gene encoding the housekeeping sigma factor sigma 70 of P. fluorescens was sequenced. The deduced RpoD protein showed 83% identity with RpoD of Pseudomonas aeruginosa and 67% identity with RpoD of Escherichia coli. Attempts to inactivate the single chromosomal rpoD gene of strain CHA0 were unsuccessful, indicating an essential role of this gene. When rpoD was carried by an IncP vector in strain CHA0, the production of both antibiotics was increased severalfold and, in parallel, protection of cucumber against disease caused by Pythium ultimum was improved, in comparison with strain CHA0.
authors.affiliation: Laboratoire de Biologie Microbienne, Université de Lausanne, Switzerland.
authors.forename: U
authors.initials: U
authors.lastname: Schnider
authors.forename: C
authors.initials: C
authors.lastname: Keel
authors.forename: C
authors.initials: C
authors.lastname: Blumer
authors.forename: J
authors.initials: J
authors.lastname: Troxler
authors.forename: G
authors.initials: G
authors.lastname: Défago
authors.forename: D
authors.initials: D
authors.lastname: Haas
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000096:biosynthesis; D000935:Antifungal Agents / Q000096:biosynthesis*; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics*; D001483:Base Sequence; D018553:Cucumis sativus / Q000382:microbiology; D012321:DNA-Directed RNA Polymerases / Q000096:biosynthesis / Q000235:genetics*; D005784:Gene Amplification / Q000235:genetics*; D005798:Genes, Bacterial / Q000235:genetics; D008969:Molecular Sequence Data; D010636:Phenols; D010696:Phloroglucinol / Q000031:analogs & derivatives / Q000378:metabolism; D018517:Plant Roots / Q000382:microbiology; D011551:Pseudomonas fluorescens / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D011758:Pyrroles; D011775:Pythium / Q000502:physiology; D015183:Restriction Mapping; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012808:Sigma Factor / Q000096:biosynthesis / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D001426:Bacterial Proteins; D010636:Phenols; D011758:Pyrroles; D012808:Sigma Factor; C095503:pyoluteorin; C059817:2,4-diacetylphloroglucinol; D010696:Phloroglucinol; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases