A Review Plant growth promoting rhizobacteria mediated amelioration of drought in crop plants

Water scarcity is one of the major global issues brought about by climate change. Besides creating socio-economic challenges, drought and osmotic stress generated by these abnormal weather conditions results in decreased agricultural productivity and deterioration of cultivable land resources. Different agronomic practices and strategies such as genetic approaches, and the use of beneficial microbes have been adopted to tackle the effects of these severe conditions. In the rhizosphere, plant-microbe interactions benefit plants through nitrogen fixation, phosphorus solubilization, microbial biofilm association with plant roots, production of antioxidants, siderophores and phytohormones, induced systemic resistance against plant pathogens and 1-aminocyclopropane 1-carboxylic acid (ACC)-deaminase activities. Inoculation of plant growth promoting rhizobacteria (PGPR) is a low cost and environment friendly biotechnology with a high probability of success in the field, and the potential to increase crop (wheat) yield by up to 18%. PGPR has the capability to survive drought and osmotic stress conditions and could be more effective at mitigating the negative impacts of drought on agricultural crops. This review highlights rhizobacteria survival, their interactions with plants under drought stress, and the ability of the PGPR's potential mechanisms to alleviate drought stress impacts by improving physiology, growth and yield of crop plants. However, multi character bacteria, or genetic manipulation used to develop strains of bacteria with multiple characteristics, could be a more effective future approach.