Genetics and functional genomics of the pseudomonas fluorescens group

Abstract

Fluorescent pseudomonads are found widely in soils and often live in a commensal relationship with plants, utilizing plant-exuded nutrients and occupying sites provided by the architecture of the plant. Such commensal species, in turn, can have profound effects on plant health by suppressing phytopathogens, enhancing local access to nutrients, degrading environmental pollutants, or inducing systemic resistance in the plant host. In addition to the basic biology of these ubiquitous bacteria, the capacity of members of the Pseudomonas fluorescens group to produce an array of bioactive secondary metabolites, including antibiotics that thwart plant pathogens and hormones which promote plant growth, is of particular interest. As concern over the ecological and health risks associated with the use of chemical pesticides in agriculture continues to mount, members of the P. fluorescens group are touted for their potential in biocontrol. While the genetics underlying some biocontrol processes is well established, many questions remain regarding ecology, gene expression, and metabolism of these organisms in natural environments. The advent of genomic approaches has allowed interrogation of sequence and expression data, which has begun to reveal the details of processes required for interactions of P. fluorescens with its environment and the considerable complexity of these interactions. Furthermore, genome comparisons and genome mining approaches have identified new features which are likely critical to the success of these organisms, but had remained undetected using other approaches. Genetic and functional genomic analyses of P. fluorescens in natural environments are giving us new insight into the way of life of these bacteria outside of the laboratory and have great potential to reveal new approaches to increasing the efficacy of P. fluorescens biocontrol.