Rhizosphere microorganisms-mediated plant responses to drought stress

As a consequence of climate change, drought has seriously restricted global food security and sustainable agricultural development. Developing crop drought resistance not only relies on diverse genetic resources, but it is also important to explore colonizing adaptive microorganisms as well as the potential beneficial associations between plants and microbes under drought conditions. Rhizosphere microorganisms that interact closely with plants play important roles in plant growth and stress tolerance. In this study, we examined the effects of drought stress on the diversity and composition of plant rhizosphere microbial communities. In the rhizosphere, Actinobacteria, Firmicutes, and arbuscular mycorrhizal fungi are often significantly enriched under drought stress. Next, we addressed the mechanisms by which rhizosphere microorganisms assist plants in resisting drought stress, particularly how they regulate plant stress responses, including the secretion of plant growth regulators, synthesis of ACC (1-aminocyclopropane-1-carboxylic acid) deaminase, production of exopolysaccharides, and enhancement of plant antioxidant enzyme activity. Finally, we suggested that exploring drought-tolerant wild relatives and their associated beneficial microbes may help microbiome-assisted plant breeding programs. In addition, the construction and application of synthetic communities of beneficial rhizosphere microbiomes may improve drought resistance and sustainable crop production in the context of global environmental change.