| Summary: | Soil salinity is one of the abiotic constraints that imbalance nutrient acquisition, hampers plant growth, and leads to potential loss in agricultural productivity. Salt-tolerant plant growth-promoting rhizobacteria (PGPR) can alleviate the adverse impacts of salt stress by mediating molecular, biochemical, and physiological status. In the present study, the bacterium <i>Bacillus mycoides</i> PM35 showed resistance up to 3 M NaCl stress and exhibited plant growth-promoting features. Under salinity stress, the halo-tolerant bacterium <i>B. mycoides</i> PM35 showed significant plant growth-promoting traits, such as the production of indole acetic acid, siderophore, ACC deaminase, and exopolysaccharides. Inoculation of <i>B. mycoides</i> PM35 alleviated salt stress in plants and enhanced shoot and root length under salinity stress (0, 300, 600, and 900 mM). The <i>B. mycoides</i> PM35 alleviated salinity stress by enhancing the photosynthetic pigments, carotenoids, radical scavenging capacity, soluble sugars, and protein content in inoculated maize plants compared to non-inoculated plants. In addition, <i>B. mycoides</i> PM35 significantly boosted antioxidant activities, relative water content, flavonoid, phenolic content, and osmolytes while reducing electrolyte leakage, H<sub>2</sub>O<sub>2</sub>, and MDA in maize compared to control plants. Genes conferring abiotic stress tolerance (<i>CzcD, sfp,</i> and <i>srfAA</i> genes) were amplified in <i>B. mycoides</i> PM35. Moreover, all reactions are accompanied by the upregulation of stress-related genes (APX and SOD). Our study reveals that <i>B. mycoides</i> PM35 is capable of promoting plant growth and increasing agricultural productivity.
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