Isolation and Characterization of Salt-Tolerant PGPR for Enhancing Moong (Vigna radiata) Growth

Author: Sanjeevani A. Bhedase and Dhanraj B. Nakade

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Abstract

Soil salinity is a major abiotic stress that severely limits plant growth and agricultural productivity by inducing osmotic imbalance, nutrient deficiency, and oxidative stress. Plant Growth-Promoting Rhizobacteria (PGPR) have emerged as a sustainable approach to enhance plant tolerance against salinity stress. This study aimed to isolate and characterize salt-tolerant PGPR from saline soils and assess their plant growth-promoting potential in Vigna radiata (moong) under controlled pot conditions. Soil samples were collected from the Shirti region, Maharashtra, India, and analyzed for physicochemical properties. PGPR were isolated using nutrient agar enrichment techniques and screened for halotolerance at varying NaCl concentrations (1%-18%). The selected isolates were identified based on morphological, biochemical, and molecular characterization, including 16S rRNA gene sequencing. Three highly salt-tolerant isolates were identified: Bacillus thuringiensis SR-121, Halomonas meridiana SR-161, and Alkalibacillus sp. SR-103. The pot experiment was conducted to evaluate their impact on plant growth parameters such as seed germination, plant height, root and shoot length, fresh and dry biomass. Seeds were inoculated with bacterial suspensions and sown in sterilized soil. The results demonstrated that bacterial inoculation significantly improved plant growth under saline conditions. Bacillus thuringiensis SR-121 exhibited the highest plant height (16.5 cm), shoot length (12.3 cm), and biomass accumulation, followed by Alkalibacillus sp. SR-103 and Halomonas meridiana SR-161. This study highlights the potential of salt-tolerant PGPR as biofertilizers for improving crop productivity in saline soils. The findings suggest that these isolates can be utilized for sustainable agriculture by enhancing plant growth and mitigating salt-induced stress. Further field trials and formulation development are recommended to establish their large-scale application in saline agricultural environments.

Keywords

PGPR, Soil Salinity, Vigna radiata, Halotolerant Bacteria, Sustainable Agriculture, Biostimulants, Salt Stress Tolerance

Conclusion

This study demonstrated the significant potential of salt-tolerant plant growth-promoting rhizobacteria (PGPR) in enhancing the growth of Vigna radiata under saline conditions. The three identified isolates—Bacillus thuringiensis SR-121, Halomonas meridiana SR-161, and Alkalibacillus sp. SR-103—exhibited varying degrees of salinity tolerance and plant growth promotion. Among them, Bacillus thuringiensis SR-121 showed the most pronounced positive impact on seed germination, plant height, and biomass accumulation. The results highlight the effectiveness of PGPR in mitigating salt stress by improving nutrient uptake, producing phytohormones, and enhancing root development. These findings support the potential application of salt-tolerant PGPR as biofertilizers for sustainable agriculture in saline environments

References

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How to cite this article

Sanjeevani A. Bhedase and Dhanraj B. Nakade (2023). Isolation and Characterization of Salt-Tolerant PGPR for Enhancing Moong (Vigna radiata) Growth. Biological Forum – An International Journal, 15(6): 1012-1019