Effect of salt stress-tolerant bacterial endophytes from Bougainvillea glabra on the growth of Triticum aestivum L. var. HD 2687 and Zea mays var. PSCL-4642

Wheat and corn crops contribute to the food security of humans by providing a nutrient-rich diet. However, their production in abiotic stress conditions such as salinity is limited. Endophytes exert a beneficial effect on plants through the decomposition of organic materials for smooth absorption, detoxification, and reduction of the effect of phytopathogenic microorganisms by increasing the immunity of host plants to resist phytopathogens and through nutrient deposition in plants responsible for reducing salt stress. The present study aimed to evaluate the NaCl tolerance efficiency of Triticum aestivum L. var. HD 2687 and Zea mays var. PSCL-4642 cultivars at the germination stage after inoculation with salt-tolerant bacterial endophyte BoGl21 isolated from Bougainvillea glabra. The seeds of both crops were tested for percentage of seed germination with/without bacteria at 50, 100, 150, and 200 mM NaCl concentrations. The BoGl21 isolate induced a significant increase in radicle length in corn (25.6 mm) as compared to that in wheat (10.3 mm) at 50 mM NaCl. However, at 100 mM NaCl, the radical length of wheat and corn seedlings was 5 mm and 8.8 mm, respectively. Inoculation of maize and wheat with the bac- terial isolate significantly increased the plumule length of the germinated seeds as compared to that of controls. BoGl21 increased the plumule length of wheat as compared to that of the control seeds by 31.9, 11.7, and 4.8 mm at 50, 100, and 150 mM salinity stress, respectively. Inoculation of corn seeds with BoGl21 at the tested NaCl levels (50, 100, and 150 mM NaCl) increased the plumule length of the germinated seeds by 33.1, 22, 13.2, and 3.2 mm, respectively. The current research results support the hypothesis that bacterial endophytes could be beneficial to minimize the toxicity of saline stress on wheat and corn at the time of germination.