Biocontrol ability of fluorescent pseudomonads genetically dissected: importance of positive feedback regulation

Root diseases caused by fungal pathogens can be suppressed by certain rhizo bacteria that effectively colonize the roots and produce extracellular anti fungal compounds. To be effective, biocontrol bacteria need to be present a t sufficiently high cell densities. These conditions favor the operation of positive feedback mechanisms that control the production of antifungal com pounds in biocontrol strains of fluorescent pseudomonads, via both transcri ptional and post-transcriptional mechanisms.