Characterization of culturable bacteria isolated from hot springs for plant growth promoting traits and effect on tomato (Lycopersicon esculentum) seedling

To elucidate the functional diversity of hot spring bacteria, 123 bacteria were isolated and screened for evaluating their multifunctional plant growth promoting (PGP) properties. The antagonistic activity against different phytopathogens showed the presence of a high amount of biocontrol bacteria in the hot springs. During screening for PGP properties, 61.0% isolates showed production of indole acetic acid and 23.6% showed inorganic phosphate solubilization qualitatively. For production of extracellular enzymes, it was found that 61.0% isolates produced lipase, 56.9% produced protease, and 43.9% produced cellulase. In extreme properties, half of the isolates showed tolerance to 5% NaCl (w/v) and 48.8% isolates survived heat shock at 70 °C. The identification of 12 multipotential bacteria based on 16S rRNA gene sequencing revealed that the bacteria belonged to Aneurinibacillus aneurinilyticus and Bacillus spp. Bacterization of tomato seeds showed that the hot spring bacteria promoted shoot height, fresh shoot weight, root length, and fresh root weight of tomato seedlings, with values ranging from 3.12% to 74.37%, 33.33% to 350.0%, 16.06% to 130.41%, and 36.36% to 318.18%, respectively, over the control. This research shows that multifunctional bacteria could be isolated from the hot springs. The outcome of this research may have a potential effect on crop production methodologies used in saline and arid environments.