Mitigation of drought stress in wheat crop by drought tolerant endophytic bacterial isolates

Abstract

Bacteria with potential to alleviate abiotic stresses in combination with plant growth promotion are extremely useful in sustainable agriculture. The present study involves the isolation and evaluation of 14 bacterial isolates obtained from four upland rice roots in varying concentrations of PEG-6000. Three potential isolates MKA2, MKA3 and MKA4 were selected for further experiments. A pot experiment was conducted with four treatments under well watered and drought conditions. Water deficit treatment was imposed by reducing the amount of water added to 25% of the field capacity. Twenty days post stress results showed that drought stress affected the physiological and biochemical parameters of uninoculated wheat seedlings. Inoculation with the three bacterial isolates diluted the adverse effects of drought on relative water content and membrane stability index, and thus improved the water use efficiency over the uninoculated control. Inoculation also improved the shoot and root biomass of wheat plants in comparison to uninoculated control treatment under drought stress. Increased levels of super oxide dismutase and catalase activities were observed in treated plants as compared to control plants thus protecting the plants from oxidative damage. Thus, these potent bacterial isolates could be used effectively to ameliorate plant water intake efficiency and improve sustainability in wheat crop under drought conditions.