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Drought is one of the most detrimental environmental stressors to plants with the potential to decrease crop yields and affect agricultural sustainability. Native bacteria with beneficial traits enhance plant growth and help avoid and reverse the effects of drought in plants to a greater extent. In the present study, we aimed to ( i ) isolate drought-tolerant Bacillus isolates from the rhizosphere soil of wheat crop grown at different locations in Jaisalmer district, Rajasthan state and (ii) further evaluate their ability to enhance plant growth and induce drought tolerance in wheat ( Var. HD-2967) grown under drought stress conditions. Of more than 100 isolates, two putative Bacillus isolates capable of tolerating 30 % polyethylene glycol-6000 (PEG-6000) [equivalent to -9.80 MPa (Megapascal)] were identified as Bacillus altitudinis DT-89 and Bacillus paramycoides DT-113. These isolates exhibited different plant growth promoting (PGP) attributes such as phosphate solubilization, and production of siderophore, exopolysaccharide, ammonia, indole acetic acid and cytokinin at low osmotic stress of 10% PEG-6000 but shown variable response at higher osmotic stress particularly at 30% PEG-6000. However, they did not show any antifungal activity and one isolate was negative for phosphate solubilization. Of two strains, B. altitudinis DT-89 function more prominently with respect to plant growth promotion and drought tolerance to plant in the early stage but protective traits of B. paramycoides DT-113 was more prominent after 75 days as evident by increased EPS (164%), root dry weight (144.44%), chlorophyll content (90.26%), SOD (389%) and proline (99.3%). The results support both the strains as a potential candidate to alleviate drought stress and enhance plant growth in the drought regions.

Drought is a global water shortage problem which poses challenge to crop productivity. Novel strategies are being tried to find out solution to sustain agriculture under drought conditions. Rhizobacteriome is an exclusive genetic material of bacteria resident to rhizosphere plays critical role to health and yield of plant. The interaction of rhizobacteriome with plant provides basis for protecting plants from various abiotic and biotic stresses. Plant growth promoting rhizobacteria (PGPR) are root-colonizing bacteria which produce array of enzymes and metabolites that assist plants to withstand harsh environmental conditions. Various formulations of rhizobacteria are being applied to enhance the tolerance or endurance to drought in crops which in turn increase crop productivity. This could be a one of the promising methods with wide potentiality to improve the growth and yield of crops under limited water resources and changing climatic conditions to ensure food security of the globe. In this review, we summarize (1) existing knowledge and understanding about the rhizobacteria, (2) their role in imparting tolerance to crops in drought conditions and (3) discuss future line of work in this frontier research area.