Leifsonia sp. and Enterobacter sp. improve physiological and biochemical adjustments in cotton under water deficit

Drought is a major limiting factor in cotton ( Gossypium hirsutum L.) cultivation, particularly in semi-arid regions, where water scarcity hinders plant growth. This study investigated the effects of rhizobacteria on the morphological and physiological responses of cotton plants under water stress. The experiment was conducted in a greenhouse using a randomized block design with a 3 × 3 × 2 factorial arrangement and five replicates. Plants were subjected to three water-holding capacity levels (100%, 50%, and 25%) and inoculated with Leifsonia sp. CR132 and Enterobacter sp .CR14, compared to a non-inoculated control, to evaluate morphological and physiological parameters. Data were subjected to analysis of variance (ANOVA), and means were compared using Tukey’s test at a 5% significance level. Under severe water stress (25%), inoculation with Leifsonia sp. CR132 and Enterobacter sp.CR14 induced superior responses compared to the control, with increases of up to 1.5-fold in superoxide dismutase, peroxidase, and catalase activities, and an increase of approximately 38% in ascorbate peroxidase activity, indicating enhanced antioxidant efficacy. Under full irrigation (100%), Leifsonia sp. CR132 also stood out, showing a more than 100% increase in total soluble proteins compared to the control group and consistently promoting greater stem growth, stem diameter, and root biomass. Enterobacter sp . CR14 increased proline accumulation by 27% and resulted in a fourfold higher membrane stability index. The results demonstrate that rhizobacteria enhance drought tolerance in cotton plants through morphological and physiological responses, highlighting the potential of Leifsonia sp. CR132 for the development of sustainable agricultural bioinoculants; however, field trials and molecular analyses are required to validate the strains under real-world environmental conditions.