Microbial Interventions for Sustainable Agriculture: Plant GrowthPromoting Rhizobacteria (PGPR) Activity of Isolates of Saline Soils from Karad Taluka, Maharashtra, India
Aug 2026· Nature Environment and Pollution Technology· Vol 25, pp. B4419· 0 citations
Abstract
Soil salinity remains a major abiotic factor limiting agricultural productivity worldwide, with the situation worsening in parts of Maharashtra, particularly Karad Taluka. This study examined saline soils from various locations within Karad, assessing their physicochemical properties and isolating indigenous halotolerant bacterial strains that exhibit plant growthpromoting rhizobacterial (PGPR) traits. The soil analysis revealed highly alkaline pH levels (8.8-9.4), elevated sodium concentrations, and deficiencies in organic carbon, nitrogen, and micronutrients. Five halotolerant bacterial isolates (Ko1, Va1, Be1, Vm1, and At1) were obtained and evaluated for PGPR activities such as phosphate and potassium solubilization, nitrogen fixation, indole-3-acetic acid (IAA) production, and siderophore synthesis. All isolates demonstrated positive results in phosphate and potassium solubilization, nitrogen fixation, and IAA production, with four also producing siderophores. Notably, isolates Be1, Vm1, and At1 showed strong performance across multiple traits, highlighting their potential as bioinoculant candidates. These findings suggest that native halotolerant PGPR strains from Karad Taluka could enhance soil fertility, improve nutrient uptake, and support plant growth in saline conditions. Future research including field trials and molecular characterization could facilitate the development of environmentally sustainable microbial formulations for saline agriculture.
It is suggested that selected halotolerant isolates possess multifunctional traits including salt tolerance and potential nutrient-solubilizing capacity, making them promising candidates for biofertilizer development and sustainable agriculture in salt-affected regions.
H. Dixit, Ranjan Singh, Sanjay Arora et al.· Journal of Soil and Water Co...· 0 citations
This study introduces L. aquatilis strain MC3 as an emerging candidate for bioinoculant development and one of the first reports for identification of L. aquatilis as multifunctional PGPR from Himalayan ecosystems.
S. Devi, Riya Chandel, D. Thakur et al.· Frontiers in Systems Biology· 0 citations
Salt-tolerant plant growth-promoting (PGP) actinobacteria play an important role in enhancing plant tolerance to salinity stress and improving crop productivity. Here, 9 morphologically distinct actinobacterial isolates (A-I) were isolated from the rhizosphere soil of Oryza sativa cultivated in the Nalgonda district, Telangana, screened for PGP characteristics (nitrogen fixation, indole-3-acetic acid production (IAA), and phosphate solubilisation) and salt tolerance. Among them, isolate H exhibited superior PGP activity and salt tolerance, growing in media containing up to 10% NaCl. Hence, it was selected for further work. Isolate H produced cellulase, lipase, amylase and showed a positive catalase reaction. It utilised glucose, fructose, galactose, and sucrose, but not maltose. Antibiotic susceptibility analysis indicated that isolate H was partially resistant to penicillin but sensitive to tetracycline, ciprofloxacin, and vancomycin. Molecular identification based on 16S rDNA sequencing (1,356 bp) revealed that isolate H shared 99.78% sequence similarity and 99% query coverage with Streptomyces levis NBRC 15423(T), suggesting that the isolate belongs to the genus Streptomyces. Seed germination efficiency (%) revealed that the 24 hrs culture (T1) of isolate H had a significantly greater effect on rice seed germination than the 48 hrs culture (T2). The germination rate of rice seeds in T1 was 86.67%, followed by T2 (72.00%), the control (62.33%), and distilled water (55.67%), indicating that the 24 hrs grown culture of isolate H may be used to enhance rice seed germination under salt stress. This study provides preliminary evidence of the potential of a Streptomyces levis strain as a PGP bacterium under saline conditions.
Anjaiah Gunja, Premsagar Korripally, Vishnuvardhan Reddy Sultanpuram et al.· Journal of Pure and Applied...· 0 citations
Plant growth-promoting rhizobacteria (PGPR) help plants grow and develop by protecting them from abiotic and biotic stresses, thereby increasing biochemicals synthesis that promote growth and nutrients uptake. Soil salinity is a major global constraint on crop productivity, and salt-tolerant PGPR offer a promising mitigation strategy. This study represents the use of PGPR consortia in the growth and augmentation of Mustard CS61 (Brassica juncea) under saline conditions. Mangrove rhizosphere soils collected from Koparkhairane (19.1045° N, 73.0033° E) to Belapur (19.0168° N, 73.0455° E), Navi Mumbai, Maharashtra, India. A total of 1,263 bacterial isolates were obtained, of which 168 isolates were screened for halotolerance. Further on the basis of purity, morphological characteristics, and PGPR traits three isolates were selected. These isolates produced significant amounts of IAA with concentrations of 59.27–81.63 µg mL⁻¹, and prominent CMC activity with hydrolysis zones of 2–5 mm. Molecular identification by 16 S rRNA sequencing revealed the potential isolates as Micrococcus luteus (Accession No. PX974661), Microbacterium barkeri (Accession No. PX974662) and (Accession No. PX974663). Plant growth promotion studies with consortia on salt tolerant variety Mustard CS61 (Brassica juncea L.) under 1% saline conditions showed 100% germination, improved seedling vigour, and increased growth. Future studies using metagenomic approaches are needed to explore the wider uncultured microbial diversity, to discover novel genes associated with stress tolerance and plant growth–promoting traits.
M. Bhat, Mayuri K Auti, Prajval Poojary· Discover Biotechnology· 0 citations