Shivangi Agnihotri and Ashwini A. Waoo
Abstract
Salinity stress significantly impairs crop productivity worldwide, with approximately 20% of irrigated lands affected and projections indicating an increase to 50% by 2050. Plant growth-promoting rhizobacteria (PGPR) offer an environmentally sustainable solution to mitigate salinity stress in crops. This study aimed to isolate halotolerant PGPR from saline soil, formulate them with carrier materials, and evaluate their efficacy in enhancing wheat tolerance to salinity stress. Nine bacterial strains were isolated from saline soil of Auraiya district, Uttar Pradesh, India, and evaluated for plant growth-promoting traits and salt tolerance. Two isolates showing superior performance, identified as Bacillus cereus MN793064.1 (HS7) and Bacillus subtilis MF765317.1 (HS3), were selected for bioformulation with talc and charcoal as carrier materials. Pot experiments with wheat (Triticum aestivum) under saline conditions demonstrated that both bioformulations significantly improved morphological parameters (root length, shoot length, biomass) and biochemical parameters (chlorophyll, carotenoid, and protein content) compared to controls. The HS3 strain with charcoal carrier showed the most substantial enhancement in root length (25.23%), chlorophyll a (77.01%), and protein content (120.13%). Metagenomic analysis of the soil revealed a diverse microbial community with predominance of Bacillus species, supporting the adaptability of the selected strains to saline conditions. These findings demonstrate that halotolerant PGPR bioformulations can effectively mitigate salinity stress in wheat, with talc being an eco-friendly alternative to charcoal as a carrier material. This approach offers a sustainable solution for improving crop productivity in salt-affected agricultural lands.