HALOTOLERANT PLANT GROWTH-PROMOTING RHIZOBACTERIA FROM SALINE SOILS: CHARACTERIZATION AND PLANT GROWTH PROMOTION UNDER SALT STRESS CONDITIONS
DOI:
https://doi.org/10.48165/abr.2026.28.01.31Keywords:
Bacillus haynesii, halotolerant PGPR, microbial bioinoculants, plant growth promotion, Shouchella clausiiAbstract
Soil salinity poses a significant challenge to global agricultural productivity, necessitating sustainable approaches to improve crop performance under salt stress. This study aimed to isolate and characterize halotolerant plant growth-promoting rhizobacteria (PGPR) from saline soils of Maharashtra and Gujarat, India, and to evaluate their salt tolerance, plant growth-promoting traits, and effects on maize and wheat growth and seed germination. Soil samples collected from Lonar Lake, Mehrun Lake, and coastal regions were analyzed for physicochemical properties. Bacterial isolates were screened for tolerance to 2–18% NaCl and for the production of indole-3-acetic acid (IAA), gibberellic acid (GA), siderophores, and exopolysaccharides (EPS). Morphological, biochemical, and 16S rRNA sequence analyses identified the selected isolates as Bacillus haynesii (B1 and B2) and Shouchella clausii (B3). All isolates tolerated NaCl concentrations up to 14%, while temperature tolerance ranged from 15 to 45°C, with optimum growth at 30–35°C. S. clausii B3 produced the highest IAA (7.5 µg mL⁻¹), whereas B. haynesii B2 showed the highest GA production (91.3%). Siderophore production peaked at 72 h, with B1 producing 68%, while EPS production was highest in B1. In pot trials, B1 significantly enhanced wheat growth, whereas B3 improved maize biomass. Seed germination assays recorded 100% germination in treated seeds, with B1 and B3 outperforming the controls in root and shoot elongation. The findings demonstrate the potential of halotolerant PGPR as effective bioinoculants for enhancing crop growth under salinity-stress conditions.
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