European Journal of Plant Pathology

, Volume 119, Issue 3, pp 311–328

Dialogues of root-colonizing biocontrol pseudomonads

Authors

  • Christophe Dubuis
    • Département de Microbiologie FondamentaleUniversité de Lausanne
  • Christoph Keel
    • Département de Microbiologie FondamentaleUniversité de Lausanne
    • Département de Microbiologie FondamentaleUniversité de Lausanne
Full Research Paper

DOI: 10.1007/s10658-007-9157-1

Cite this article as:
Dubuis, C., Keel, C. & Haas, D. Eur J Plant Pathol (2007) 119: 311. doi:10.1007/s10658-007-9157-1

Abstract

Among biocontrol agents that are able to suppress root diseases caused by fungal pathogens, root-colonizing fluorescent pseudomonads have received particular attention because many strains of these bacteria trigger systemic resistance in host plants and produce antifungal compounds and exoenzymes. In general, the expression of these plant-beneficial traits is regulated by autoinduction mechanisms and may occur on roots when the pseudomonads form microcolonies. Three major classes of antibiotic compounds reviewed here in detail (2,4-diacetylphloroglucinol, pyoluteorin and various phenazine compounds) are all produced under cell population density-dependent autoinduction control acting at transcriptional and post-transcriptional levels. This regulation can either be reinforced or attenuated by a variety of chemical signals emanating from the pseudomonads themselves, other microorganisms or root exudates. Signals stimulating biocontrol factor expression via the Gac/Rsm signal transduction pathway in the biocontrol strain Pseudomonas fluorescens CHA0 are synthesized by many different plant-associated bacteria, warranting a more detailed investigation in the future.

Keywords

Antibiotic compoundsBiocontrolGacS/GacAQuorum sensingPseudomonasRhizosphere

Abbreviations

AHL

N-acyl-homoserine lactone

AI-2

Autoinducer 2

DAPG

2,4-Diacetylphloroglucinol

HCN

Hydrogen cyanide

IAA

Indole-3-acetic acid

PCA

Phenazine-1-carboxylic acid

PLT

Pyoluteorin

PQS

Pseudomonas quinolone signal

QS

Quorum sensing

Copyright information

© KNPV 2007