U.S. Department of Agriculture-Agricultural Research Service, Root Disease and Biological Control Research Unit, Washington State University, Pullman 99164-6430
Pseudomonas spp. are ubiquitous bacteria in agricultural soils and have many traits that make them well suited as biocontrol agents of soilborne pathogens. Tremendous progress has been made in characterizing the process of root colonization by pseudomonads, the biotic and abiotic factors affecting colonization, bacterial traits and genes contributing to rhizosphere competence, and the mechanisms of pathogen suppression. This review looks back over the last 30 years of Pseudomonas biocontrol research and highlights key studies, strains, and findings that have had significant impact on shaping our current understanding of biological control by bacteria and the direction of future research.