Pseudomonas fluorescens

Pseudomonas fluorescens is a Gram-negative environmental bacterium often studied as a key contributor to plant and soil health. Pan-genome analysis suggests that P. fluorescens is not a single species, but is better described as a species complex (a set of closely related species that are very similar in appearance and traits), within which there are more than 50 species along with many unclassified isolates. This complex is highly diverse, both genetically and ecologically, with species inhabiting a variety of environments, including soil, water, plant tissues, and even dairy products. The species complex can be further divided into multiple phylogenomic groups, each exhibiting distinct traits, including plant growth promotion, biocontrol abilities, and the capacity to degrade pollutants. Novel species within the complex continue to be isolated from the rhizosphere, indicating that there is likely to be a large reservoir of bacteria belonging to the P. fluorescens species complex remaining uncharacterised.