Plant Growth-Promoting Endophytic Bacterial Community Inhabiting the Leaves of (Lam.) DC Inherent to Arid Regions.

In this study, 15 bacterial endophytes linked with the leaves of the native medicinal plant were isolated and identified as , , , , , , and These isolates exhibited variant tolerances to salt stress and showed high efficacy in indole-3-acetic acid (IAA) production in the absence/presence of tryptophan. The maximum productivity of IAA was recorded for BI-8 and BI-10 with values of 117 ± 6 and 108 ± 4.6 μg mL, respectively, in the presence of 5 mg mL tryptophan after 10 days. These two isolates had a high potential in phosphate solubilization and ammonia production, and they showed enzymatic activities for amylase, protease, xylanase, cellulase, chitinase, and catalase. In vitro antagonistic investigation showed their high efficacy against the three phytopathogens , , and , with inhibition percentages ranging from 20% ± 0.2% to 52.6% ± 0.2% ( ≤ 0.05). Therefore, these two endophytic bacteria were used as bio-inoculants for maize seeds, and the results showed that bacterial inoculations significantly increased the root length as well as the fresh and dry weights of the roots compared to the control plants. The plant inoculated with the two endophytic strains BI-8 and BI-10 significantly improved ( ≤ 0.05) the growth performance as well as the nutrient uptake compared with an un-inoculated plant.