title: Transcriptional and antagonistic responses of Pseudomonas fluorescens Pf0-1 to phylogenetically different bacterial competitors.
abstract: The ability of soil bacteria to successfully compete with a range of other microbial species is crucial for their growth and survival in the nutrient-limited soil environment. In the present work, we studied the behavior and transcriptional responses of soil-inhabiting Pseudomonas fluorescens strain Pf0-1 on nutrient-poor agar to confrontation with strains of three phylogenetically different bacterial genera, that is, Bacillus, Brevundimonas and Pedobacter. Competition for nutrients was apparent as all three bacterial genera had a negative effect on the density of P. fluorescens Pf0-1; this effect was most strong during the interaction with Bacillus. Microarray-based analyses indicated strong differences in the transcriptional responses of Pf0-1 to the different competitors. There was higher similarity in the gene expression response of P. fluorescens Pf0-1 to the Gram-negative bacteria as compared with the Gram-positive strain. The Gram-negative strains did also trigger the production of an unknown broad-spectrum antibiotic in Pf0-1. More detailed analysis indicated that expression of specific Pf0-1 genes involved in signal transduction and secondary metabolite production was strongly affected by the competitors' identity, suggesting that Pf0-1 can distinguish among different competitors and fine-tune its competitive strategies. The results presented here demonstrate that P. fluorescens Pf0-1 shows a species-specific transcriptional and metabolic response to bacterial competitors and provide new leads in the identification of specific cues in bacteria-bacteria interactions and of novel competitive strategies, antimicrobial traits and genes.
authors.affiliation: Netherlands institute of Ecology, Center for Terrestrial Ecology, Heteren, The Netherlands. p.garbeva@nioo.knaw.nl
authors.forename: Paolina
authors.initials: P
authors.lastname: Garbeva
authors.forename: Mark W
authors.initials: MW
authors.lastname: Silby
authors.forename: Jos M
authors.initials: JM
authors.lastname: Raaijmakers
authors.forename: Stuart B
authors.initials: SB
authors.lastname: Levy
authors.forename: Wietse de
authors.initials: Wd
authors.lastname: Boer
mesh_terms: D020561:Alphaproteobacteria / Q000254:growth & development; D000596:Amino Acids / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000096:biosynthesis; D000898:Antibiosis; D001407:Bacillus / Q000254:growth & development; D001426:Bacterial Proteins / Q000235:genetics; D041963:Bacteroidetes / Q000254:growth & development; D015964:Gene Expression Regulation, Bacterial; D011551:Pseudomonas fluorescens / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D012269:Ribosomal Proteins / Q000235:genetics; D015398:Signal Transduction; D012988:Soil Microbiology; D014158:Transcription, Genetic
chemical_list: D000596:Amino Acids; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D012269:Ribosomal Proteins