Improving salinity tolerance in wheat plants via inoculation with Azospirillum brasilense and Bacillus subtilis for enhanced biomass, growth and physiological process

The study seeks to contribute novel insights into the efficacy of rhizobacteria, simultaneous Azospirillum brasilense and Bacillus subtilis inoculation as a means to not only mitigate the detrimental impacts of salt stress but also to potentially achieve superior results in terms of wheat biomass production. The experimental design involved a pot experiment where wheat plants were subjected to nine treatments {T₀ = Control [No seed inoculation with any bacterial strain + Non-saline soil (2.16 dS/m)], T₁ = Saline soil (6.0 dS/m), T₂ = Saline soil + Azospirillum brasilense, T₃ = Saline soil + Bacillus subtilis, T₄ = Saline soil + A. brasilense + B. subtilis, T₅ = Highly saline (10 dS/m), T₆ = Highly saline + Azospirillum brasilense, T₇ = Highly saline + Bacillus subtilis, T₈ = Highly saline + A. brasilense + B. subtilis}. A. brasilense and B. subtilis individually exhibited positive effects in alleviating the detrimental influence of salt stress but combined application of both rhizobacteria showed superior effectiveness, particularly in saline and highly saline environments. A. brasilense and B. subtilis were found to enhance wheat plant growth by fostering improvements in photosynthesis, chlorophyll content, and crop growth rate, particularly in stressful conditions. Both rhizobacteria were improved biomass of wheat crop and other growth parameters. This study demonstrated the potential of A. brasilense and B. subtilis as beneficial rhizobacteria for enhancing wheat biomass production in the face of salt stress. Combined application of A. brasilense and B. subtilis could be a promising strategy for improving wheat growth under saline soils.