Pseudomonas protegens

General characteristics

Like P. fluorescens, Pseudomonas protegens is a typical soil microorganism with an extremely versatile metabolism, and can be isolated from roots of various plant species. The microbe is strictly aerobe (no reduction of nitrate) and oxidase-positive.

The name

The word Pseudomonas means 'false unit', being derived from the Greek words pseudo (Greek: ψευδο 'false') and monas (Latin: monas, fr. Greek: μονάς/μονάδα 'a single unit'). The species name 'protegens' refers to the bacterium's ability to protect plants from soil-borne phytopathogens.

Genome sequencing projects

The genome of P. protegens strain Pf-5 has been sequenced and published.

Biocontrol properties

Pseudomonas protegens has been studied for more than twenty years for its biocontrol properties. Most studies have been carried out with the model strains CHA0 and Pf-5.

Insecticidal activity

In addition to efficiently protect plant roots against phytopathogenic fungi (described in detail for P. fluorescens), Pseudomonas protegens was discovered to display toxicity towards certain insects upon oral ingestion or injection into the hemolymph. The insecticidal activity of the bacterium was found to be in part due to the production of an insect toxin (FitD), which is similar to a well-known protein toxin (Mcf) produced by Photorhabdus luminescens.

References

References

1. (2011). "''Pseudomonas protegens'' sp. nov., widespread plant-protecting bacteria producing the biocontrol compounds 2,4-diacetylphloroglucinol and pyoluteorin". Systematic and Applied Microbiology.
2. (2005). "Biological control of soil-borne pathogens by fluorescent pseudomonads". Nature Reviews Microbiology.
3. "Pseudomonas fluorescens Pf-5 Genome Page".
4. (2007). "The genomic sequence of ''Pseudomonas fluorescens'' Pf-5: Insights into biological control". Phytopathology.
5. (2003). "Regulation of antibiotic production in root-colonizing ''Pseudomonas'' spp. and relevance for biological control of plant disease". Annu. Rev. Phytopathol..
6. (June 2025). "Molecular analysis of a novel gene cluster encoding an insect toxin in plant-associated strains of ''Pseudomonas fluorescens''". Environmental Microbiology.
7. (2012). "Oral insecticidal activity of plant-associated pseudomonads". Environmental Microbiology.
8. (2009). "''Pseudomonas fluorescens'' CHA0 can kill subterranean termite ''Odontotermes obesus'' by inhibiting cytochrome c oxidase of the termite respiratory chain". FEMS Microbiol Lett.