title: Surface motility in Pseudomonas sp. DSS73 is required for efficient biological containment of the root-pathogenic microfungi Rhizoctonia solani and Pythium ultimum.
abstract: Pseudomonas sp. DSS73 was isolated from the rhizoplane of sugar beet seedlings. This strain exhibits antagonism towards the root-pathogenic microfungi Pythium ultimum and Rhizoctonia solani. Production of the cyclic lipopeptide amphisin in combination with expression of flagella enables the growing bacterial culture to move readily over the surface of laboratory media. Amphisin is a new member of a group of dual-functioning compounds such as tensin, viscosin and viscosinamid that display both biosurfactant and antifungal properties. The ability of DSS73 to efficiently contain root-pathogenic microfungi is shown to arise from amphisin-dependent surface translocation and growth by which the bacterium can lay siege to the fungi. The synergistic effects of surface motility and synthesis of a battery of antifungal compounds efficiently contain and terminate growth of the microfungi.
authors.affiliation: Section of Molecular Microbiology, Biocentrum-DTU, Building 301, Technical University of Denmark, 2800 Lyngby, Denmark.
authors.forename: Jens B
authors.initials: JB
authors.lastname: Andersen
authors.forename: Birgit
authors.initials: B
authors.lastname: Koch
authors.forename: Tommy Harder
authors.initials: TH
authors.lastname: Nielsen
authors.forename: Dan
authors.initials: D
authors.lastname: Sørensen
authors.forename: Michael
authors.initials: M
authors.lastname: Hansen
authors.forename: Ole
authors.initials: O
authors.lastname: Nybroe
authors.forename: Carsten
authors.initials: C
authors.lastname: Christophersen
authors.forename: Jan
authors.initials: J
authors.lastname: Sørensen
authors.forename: Søren
authors.initials: S
authors.lastname: Molin
authors.forename: Michael
authors.initials: M
authors.lastname: Givskov
mesh_terms: D000898:Antibiosis; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D027461:Beta vulgaris / Q000382:microbiology*; D003470:Culture Media; D009068:Movement; D010456:Peptides, Cyclic / Q000378:metabolism / Q000494:pharmacology; D010572:Pest Control, Biological; D010935:Plant Diseases / Q000382:microbiology; D018517:Plant Roots / Q000382:microbiology; D011549:Pseudomonas / Q000254:growth & development / Q000502:physiology*; D011775:Pythium / Q000187:drug effects / Q000254:growth & development*; D012232:Rhizoctonia / Q000187:drug effects / Q000254:growth & development*; D012988:Soil Microbiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D010456:Peptides, Cyclic; D014157:Transcription Factors; C438267:amphisin