Pseudomonas putida
Pseudomonas putida is a beneficial bacterium known for producing growth-promoting substances like indole-3-acetic acid (IAA), enhancing plant development and root architecture. It degrades organic pollutants,…
Strength
1 x 10⁸ CFU per gram / 1 x 10⁹ CFU per gram
Benefits
Scientific References
Pseudomonas putida for Industrial Applications
Weimer et al. (2020)A comprehensive review detailing the advances in genetic engineering, systems biology, and biotechnological exploitation of P. putida as an industrial microbial cell factory. It covers the production of bio-based chemicals, adaptation to toxic environments, and integration with synthetic biology platforms.Read here
D’Arrigo et al. (2015)This study used differential RNA-sequencing (dRNA-seq) to map transcriptional start sites in P. putida KT2440, revealing promoter architecture and untranslated regions that are critical for optimizing gene expression in industrial strain design.Read here
Nelson et al. (2002)The complete genome sequence of P. putida KT2440 is presented, identifying the organism’s extensive metabolic capabilities, solvent resistance, and non-pathogenic status. The genome is a cornerstone for metabolic engineering in industrial settings.Read here
Udaondo et al. (2016)Provides a pangenomic comparison of nine P. putida strains. This study highlights conserved pathways for carbon metabolism and aromatic compound degradation, confirming their robustness in diverse industrial bioprocesses.Read here
Song & Zhang (2012)Identifies and localizes mobile genomic islands in several P. putida strains, including genes for salt resistance, stress tolerance, and efflux systems. These traits enhance survival and productivity in chemically harsh industrial environments. Read here
Kivisaar (2020)Reviews P. putida’s historical development and adaptation as a model for biotechnological research, with a focus on regulatory mechanisms, stress responses, and genomic plasticity relevant to industrial-scale applications. Read here
Mode of Action
1. Biocontrol via Nutrient Competition and Siderophores
P. putida can protect plants against pathogens without relying on toxic or antibiotic substances. Instead, it uses a strategy based on nutrient competition, especially for iron.
Siderophores like pyoverdine are secreted to tightly bind iron from the environment, making it unavailable to competing microorganisms (including plant pathogens), thereby suppressing their growth.
Notably, P. putida B2017 does not produce common antibiotics like pyocyanin or pyrrolnitrin, but still exhibits biocontrol activity due to pyoverdine production (Daura-Pich et al., 2020).
2. Plant Growth Promotion and Rhizosphere Colonization
P. putida is a well-known Plant Growth-Promoting Rhizobacteria (PGPR) that helps plants grow better by:
Mobilizing nutrients (e.g., phosphorus solubilization, nitrogen metabolism).
Inducing systemic resistance in plants against bacterial, viral, and fungal pathogens (Park et al., 2011).
Efficiently colonizing the rhizosphere (plant root environment) due to genes promoting motility, chemotaxis, and biofilm formation (Molina et al., 2020).
These abilities allow P. putida to coexist with plants, creating a beneficial plant-microbe relationship.
3. Environmental Bioremediation and Stress Tolerance
Thanks to its metabolic versatility, P. putida can degrade a wide variety of toxic pollutants, including hydrocarbons, solvents, and xenobiotics. This makes it a powerful tool in bioremediation (cleaning up contaminated environments).
It possesses catabolic genes for the breakdown of aromatic compounds, heavy metals, and other industrial pollutants (Udaondo et al., 2016).
The strain KT2440 is widely used as a model for industrial biotechnology due to its non-pathogenic nature and ability to survive under stress conditions such as high salinity and oxidative stress (Nelson et al., 2002).
4. Production of Antimicrobial Compounds (Strain-Specific)
While not all P. putida strains produce antimicrobial compounds, certain isolates do exhibit this trait:
Strains like W15Oct28 and BW11M1 produce putisolvins (cyclic lipopeptides), bacteriocins, tailocins, and other hydrophobic antimicrobial compounds that are active against Staphylococcus aureus, P. aeruginosa, and P. syringae (Ye et al., 2014); (Ghequire et al., 2016).
These antimicrobial compounds often work under specific environmental conditions such as low iron availability, adding a layer of ecological control to their use.
5. Capsule Formation and Biofilm Development
P. putida can form a polysaccharide capsule that helps in:
Surface adhesion (critical for root colonization and biofilm development).
Protection against environmental stresses, such as desiccation and immune responses in the case of exposure to a host (Kachlany & Ghiorse, 2009).
Biofilm formation is also important for both plant interactions and survival in industrial settings.
Additional Info
Pseudomonas putida acts mainly through non-toxic mechanisms like siderophore production, rhizosphere colonization, metabolic versatility for bioremediation, and, in some strains, production of antimicrobial compounds, making it a valuable tool in agriculture and environmental biotechnology.
Dosage & Application
Seed Coating/Seed Treatment: 1 kg of seeds will be coated with a slurry mixture of 10 g of Pseudomonas putida and 10 g of crude sugar in sufficient water. The coated seeds will then be dried in shade and sow or broadcast in the field
Seedling Treatment: Dip the seedlings into the mixture of 100 grams of Pseudomonas putida and sufficient amount of water.
Soil Treatment: Mix 3-5 kg per acre of Pseudomonas putida with organic manure/organic fertilizers. Incorporate the mixture and spread into the field at the time of planting/sowing.
Irrigation: Mix 3 kg per acre of Pseudomonas putida in a sufficient amount of water and run into the drip lines.
FAQ
What are the primary mechanisms by which Pseudomonas putida exhibits biocontrol activity?
P. putida exhibits biocontrol through several integrated mechanisms:
Siderophore-mediated iron sequestration: Pyoverdine is the primary siderophore produced, depriving competing phytopathogens of essential iron, thus limiting their proliferation (Daura-Pich et al., 2020).
Biofilm formation and rhizosphere competence: Biofilm-related genes facilitate stable colonization of the plant rhizosphere, enhancing competition and persistence in soil ecosystems (Udaondo et al., 2016).
Induced systemic resistance (ISR): Certain strains (e.g., B001) can prime host plant immunity, leading to enhanced resistance to fungal, bacterial, and viral pathogens (Park et al., 2011).
What secondary metabolites does P. putida produce, and what are their functions?
While P. putida lacks traditional antibiotic biosynthesis clusters seen in P. aeruginosa, several strains synthesize specialized metabolites with ecological and antimicrobial roles:
Putisolvins: Lipopeptides with surfactant and antimicrobial properties, also involved in biofilm dispersal (Ye et al., 2014).
Tailocins and bacteriocins: Bacteriophage-derived protein complexes with lethal activity against closely related bacterial strains (Ghequire et al., 2016).
TonB-dependent receptors: Facilitate siderophore piracy, allowing utilization of exogenous siderophores from other microbes (Ye et al., 2014).
What genomic features underlie the adaptability of P. putida?
Large and flexible genome (~6.1–6.5 Mb): Rich in genes for xenobiotic degradation, nutrient uptake, and stress tolerance (Nelson et al., 2002).
Mobile genetic elements: Genomic islands encode catabolic operons, efflux pumps, and stress tolerance mechanisms such as ectoine biosynthesis (Song & Zhang, 2012).
Metabolic versatility: Core genome includes complete pathways for the Entner–Doudoroff, pentose phosphate, and aromatic compound degradation cycles (Udaondo et al., 2016).
What makes P. putida suitable for industrial biotechnology?
Tolerant to solvents and oxidative stress: Enables its use in biocatalysis and metabolic engineering under harsh conditions (Weimer et al., 2020).
Compatibility with genetic tools: KT2440, a model strain, has been adapted for synthetic biology using CRISPR-Cas systems and modular plasmids for pathway design (Weimer et al., 2020).
Production of value-added products: Used to biosynthesize bioplastics, phenylalanine derivatives, and other platform chemicals from renewable feedstocks (Kivisaar, 2020).
Does P. putida form biofilms or extracellular structures?
Yes. Several strains can form:
Capsules composed of complex polysaccharides, contributing to adhesion, desiccation resistance, and evasion of protozoan grazing (Kachlany & Ghiorse, 2009).
Biofilms: Promoted by flagellar genes, quorum sensing elements, and cyclic-di-GMP signaling pathways essential for colonization and surface persistence (Udaondo et al., 2016).
