Potential of Bacillus aryabhattai to Promote Plant Growth and Mitigate the Effects of Water Deficit

Abstract

Water deficit is one of the main factors limiting soybean productivity, impairing plant growth and reducing crop yield potential. In this context, the use of plant growth-promoting rhizobacteria (PGPR) has emerged as a promising strategy to enhance plant tolerance to abiotic stresses and improve crop development. This study aimed to evaluate the effects of soybean seed inoculation with Bacillus aryabhattai on seed physiological performance during germination and plant growth under water-deficit conditions. Two experiments were conducted. In the first experiment, a completely randomized design was adopted in a factorial arrangement, evaluating seed inoculation (with or without aryabhattai) and water availability (with or without water deficit). Shoot and root length, as well as shoot and root fresh and dry biomass, were determined. In the second experiment, the seed physiological performance during germination of inoculated and non-inoculated seeds was evaluated by assessing seedling biomass accumulation. Seed inoculation significantly promoted shoot and root growth under both well-watered and water-deficit conditions. Inoculated plants subjected to water restriction exhibited greater length and biomass accumulation than non-inoculated plants, demonstrating enhanced tolerance to drought stress. In addition, inoculation increased shoot biomass accumulation during the seedling stage, indicating greater early vigor. Overall, the results demonstrate that Bacillus aryabhattai has considerable potential as a soybean seed inoculant, promoting plant growth and contributing to improved crop resilience under water-deficit conditions.