New strategies to improve crop yield include the incorporation of plant growth-promoting bacteria in agricultural practices. The non-pathogenic bacterium Pseudomonas putida KT2440 is an excellent root colonizer of crops of agronomical importance and has been shown to activate the induced systemic resistance of plants in response to certain foliar pathogens. In this work, we have analyzed additional plant growth promotion features of this strain. We show it can tolerate high NaCl concentrations and determine how salinity influences traits such as the production of indole compounds, siderophore synthesis, and phosphate solubilization. Inoculation with P. putida KT2440 significantly improved seed germination and root and stem length of soybean and corn plants under saline conditions compared to uninoculated plants, whereas the effects were minor under non-saline conditions. Also, random transposon mutagenesis was used for preliminary identification of KT2440 genes involved in bacterial tolerance to saline stress. One of the obtained mutants was analyzed in detail. The disrupted gene encodes a predicted phosphoethanolamine-lipid A transferase (EptA), an enzyme described to be involved in the modification of lipid A during lipopolysaccharide (LPS) biosynthesis. This mutant showed changes in exopolysaccharide (EPS) production, low salinity tolerance, and reduced competitive fitness in the rhizosphere.
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http://dx.doi.org/10.1007/s00253-020-10516-z | DOI Listing |
Curr Opin Biotechnol
January 2025
State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China. Electronic address:
Nonmodel microbes with unique advantages are emerging as industrial platforms, driven by advances in genetic engineering and omics technologies. Notable examples include the versatile soil bacterium Pseudomonas putida KT2440, the halophilic Halomonas bluephagenesis TD01, and the ethanologenic Zymomonas mobilis ZM4. While all three primarily use the Entner-Doudoroff pathway for glucose metabolism, they differ in various metabolic pathways and product synthesis.
View Article and Find Full Text PDFJ Biol Eng
January 2025
Department of Bioprocess Engineering, Institute of Food Science and Biotechnology, University of Hohenheim, Fruwirthstr. 12, 70599, Stuttgart, Germany.
Background: In biomanufacturing of surface-active agents, such as rhamnolipids, excessive foaming is a significant obstacle for the development of high-performing bioprocesses. The exploitation of the inherent tolerance of Pseudomonas putida KT2440, an obligate aerobic bacterium, to microaerobic conditions has received little attention so far. Here low-oxygen inducible promoters were characterized in biosensor strains and exploited for process control under reduction of foam formation by low aeration and stirring rates during biosynthesis of rhamnolipids.
View Article and Find Full Text PDFNPJ Syst Biol Appl
January 2025
The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA, 94608, USA.
Genome-scale metabolic models (GSMM) are commonly used to identify gene deletion sets that result in growth coupling and pairing product formation with substrate utilization and can improve strain performance beyond levels typically accessible using traditional strain engineering approaches. However, sustainable feedstocks pose a challenge due to incomplete high-resolution metabolic data for non-canonical carbon sources required to curate GSMM and identify implementable designs. Here we address a four-gene deletion design in the Pseudomonas putida KT2440 strain for the lignin-derived non-sugar carbon source, p-coumarate (p-CA), that proved challenging to implement.
View Article and Find Full Text PDFMicrob Cell Fact
December 2024
Department of Chemical Engineering, University of Waterloo, Waterloo, Canada.
Background: Pseudomonas putida KT2440, a non-pathogenic soil bacterium, is a key platform strain in synthetic biology and industrial applications due to its robustness and metabolic versatility. Various systems have been developed for genome editing in P. putida, including transposon modules, integrative plasmids, recombineering systems, and CRISPR/Cas systems.
View Article and Find Full Text PDFACS Synth Biol
January 2025
Department of Chemical and Biological Engineering, University of Wisconsin - Madison, Madison, Wisconsin 53706, United States.
The soil environment affected by plant roots and their exudates, termed the rhizosphere, significantly impacts crop health and is an attractive target for engineering desirable agricultural traits. Engineering microbes in the rhizosphere is one approach to improving crop yields that directly minimizes the number of genetic modifications made to plants. Soil microbes have the potential to assist with nutrient acquisition, heat tolerance, and drought response if they can persist in the rhizosphere in the correct numbers.
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