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Development of heavy metal-resistant mutants of phosphate solubilizing Pseudomonas sp. NBRI 4014 and their
Abhishek Gupta1, Jean Marie Meyer, Reeta Goel
1Department of Microbiology, CBSH, G.B. Pant University of Agriculture & Technology, Pantnagar, 263145, India.
Abstract:
Pseudomonas sp. NBRI 4014 is a potent phosphorus solubilizer (284 microg/ml). It also produced significant levels of siderophore (143.87 microg/ml) and IAA (5.6 microg/ml). Siderotyping indicated it was P. aeruginosa siderovar 1. Cadmium (180 microM), nickel (420 microM), and chromium (370 microM) resistant mutants were developed and characterized for their PGPR properties. Mutants were stable under non-selective pressure. In cases of nickel and cadmium, there were reductions of the siderophore levels. However, they were able to promote root and shoot elongation in soybeans ( Glycine max PK 564) at a significant level (p < 0.05) in the presence of metals unfamiliar to the wild type. The persistence and stability of mutants were evident in rhizospheric soil, thus their exploitation for polluted/contaminated sites was supported.
Insights
This study engineered heavy metal-resistant Pseudomonas strains for agricultural use. These plant growth-promoting bacteria (PGPR) effectively enhanced soybean growth even in contaminated soils.
Area of Science:
- Microbiology
- Environmental Science
- Plant Science
Background:
- Pseudomonas sp. NBRI 4014 exhibits potent plant growth-promoting traits, including phosphorus solubilization, siderophore, and indole-3-acetic acid (IAA) production.
- Siderotyping confirmed the isolate as Pseudomonas aeruginosa siderovar 1, a known plant growth-promoting rhizobacteria (PGPR).
Purpose of the Study:
- To develop and characterize heavy metal-resistant mutants of Pseudomonas sp. NBRI 4014.
- To evaluate the plant growth-promoting capabilities of these mutants in the presence of cadmium, nickel, and chromium.
- To assess the stability and persistence of the mutants in rhizospheric soil for potential application in contaminated environments.
Main Methods:
- Development of cadmium, nickel, and chromium resistant mutants from Pseudomonas sp. NBRI 4014.
- Characterization of PGPR properties, including siderophore and IAA production, in the developed mutants.
- Evaluation of mutant efficacy in promoting soybean (Glycine max PK 564) root and shoot elongation under metal stress.
Main Results:
- Mutants resistant to cadmium (180 microM), nickel (420 microM), and chromium (370 microM) were successfully developed and remained stable.
- Nickel and cadmium-resistant mutants showed reduced siderophore levels but maintained significant plant growth promotion.
- Mutants effectively promoted soybean root and shoot elongation in the presence of unfamiliar heavy metals, demonstrating stability in rhizospheric soil.
Conclusions:
- Heavy metal-resistant mutants of Pseudomonas sp. NBRI 4014 retain significant plant growth-promoting abilities.
- These engineered PGPR are suitable for use in metal-polluted soils, offering a viable strategy for phytoremediation and crop production.
- The stability and persistence of mutants in the rhizosphere support their application in contaminated agricultural sites.
