title: Role of secondary metabolites in the interaction between Pseudomonas fluorescens and soil microorganisms under iron-limited conditions.
abstract: Microorganisms can be versatile in their interactions with each other, being variously beneficial, neutral or antagonistic in their effect. Although this versatility has been observed among many microorganisms and in many environments, little is known regarding the mechanisms leading to these changes in behavior. In the present work, we analyzed the mechanism by which the soil bacterium Pseudomonas fluorescens BBc6R8 shifts from stimulating the growth of the ectomycorrhizal fungus Laccaria bicolor S238N to killing the fungus. We show that among the three secondary metabolites produced by the bacterial strain-the siderophores enantio-pyochelin and pyoverdine, and the biosurfactant viscosin-the siderophores are mainly responsible for the antagonistic activity of the bacterium under iron-limited conditions. While the bacterial strain continues to produce beneficial factors, their effects are overridden by the action of their siderophores. This antagonistic activity of the strain P. fluorescens BBC6R8 in iron-depleted environments is not restricted to its influence on L. bicolor, since it was also seen to inhibit the growth of the actinomycete Streptomyces ambofaciens ATCC23877. We show that the strain P. fluorescens BBc6R8 uses different strategies to acquire iron, depending on certain biotic and abiotic factors.
authors.affiliation: INRA, Interactions Arbres-Microorganismes, UMR1136, Université de Lorraine, F-54280 Champenoux, France deveau@nancy.inra.fr.
authors.forename: Aurélie
authors.initials: A
authors.lastname: Deveau
authors.affiliation: Department of Pharmaceutical Biology, Pharmaceutical Institute, University of Tuebingen, Auf der Morgenstelle 8, 72076 Tuebingen, Germany.
authors.forename: Harald
authors.initials: H
authors.lastname: Gross
authors.affiliation: INRA, Interactions Arbres-Microorganismes, UMR1136, Université de Lorraine, F-54280 Champenoux, France.
authors.forename: Béatrice
authors.initials: B
authors.lastname: Palin
authors.affiliation: Department of Pharmaceutical Biology, Pharmaceutical Institute, University of Tuebingen, Auf der Morgenstelle 8, 72076 Tuebingen, Germany Department of Biological Sciences, Forman Christian College, Ferozepur Road, Lahore 54600, Pakistan.
authors.forename: Samina
authors.initials: S
authors.lastname: Mehnaz
authors.affiliation: Department of Pharmaceutical Biology, Pharmaceutical Institute, University of Tuebingen, Auf der Morgenstelle 8, 72076 Tuebingen, Germany.
authors.forename: Max
authors.initials: M
authors.lastname: Schnepf
authors.affiliation: Dynamique des Génomes et Adaptation Microbienne, UMR1128, Université de Lorraine, Faculté des Sciences et Technologies-Campus Aiguillettes, Vandœuvre-lès-Nancy, F-54506, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Leblond
authors.affiliation: Collaborative Mass Spectrometry Innovation Center, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, CA 92093, USA.
authors.forename: Pieter C
authors.initials: PC
authors.lastname: Dorrestein
authors.affiliation: Dynamique des Génomes et Adaptation Microbienne, UMR1128, Université de Lorraine, Faculté des Sciences et Technologies-Campus Aiguillettes, Vandœuvre-lès-Nancy, F-54506, France.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Aigle
mesh_terms: D007501:Iron / Q000378:metabolism*; D038821:Mycorrhizae / Q000378:metabolism; D009842:Oligopeptides; D010636:Phenols; D011551:Pseudomonas fluorescens / Q000254:growth & development / Q000378:metabolism* / Q000502:physiology; D017262:Siderophores / Q000378:metabolism; D012987:Soil; D012988:Soil Microbiology; D013302:Streptomyces / Q000378:metabolism; D013844:Thiazoles
chemical_list: D009842:Oligopeptides; D010636:Phenols; D017262:Siderophores; D012987:Soil; D013844:Thiazoles; C025316:pyochelin; C042453:pyoverdin; D007501:Iron
keywords: antagonism; iron; mutualism; mycorrhiza helper bacteria; siderophores; viscosin