Microbial enhancement of crop abiotic stress tolerance: mechanisms and applications

Crops aimed at nourishing an exponentially increasing population are frequently vulnerable to a diversity of adverse ecological conditions. Due to climate change, extreme events including flooding, droughts, heat, and frost are expected to further upsurge in the future. To cope with such effects, a wide range of mitigation and adaptation approaches are needed. Even though plants have been engineered to endure stressful conditions, and some have also developed ways of regulating their metabolism, there is still a scarcity of food supply. To mitigate abiotic stresses, an alternate strategy is to investigate the possibility of utilizing rhizosphere microbes, as it is a cost-effective biological approach for abiotic stress management, which can be employed on a short-term basis. In this review, the various mechanisms, including promoting plant growth, up-regulating the expression of antioxidant and dehydration response genes, reducing ethylene levels, and stimulating the production of soluble phosphates and plant hormones by which microorganisms regulate plants’ reactions to different abiotic stresses, such as high temperature, drought, low temperature, metal toxicity damage, and salinity, are discussed. With this review, we aim to encourage the strategy of using microbial technology to feed the world’s population under the existing resource conditions and propose that the improvement of crops’ abiotic stress tolerance by microbial technology is the key to making crops more adaptable to future climatic conditions and proposing it as promising and feasible future technology.