Role of the Plant Root Microbiome in Abiotic Stress Tolerance

Abstract

During a growing season, agricultural crops are frequently exposed to abiotic stresses, which hinder plant growth and reduce crop productivity. Abiotic stresses include extreme temperatures, drought, submergence, soil salinization, and nutrient imbalances, and many of these stresses are predicted to increase in frequency or severity in the coming century. Maintaining high levels of crop productivity under increasingly suboptimal growth environments will require the development of new agronomic tools. One new and promising strategy involves the utilization of microorganisms, which have been shown to be capable of mitigating abiotic stresses, and the plant microbiome has the potential of promoting growth and protecting the host through a variety of molecular mechanisms. While studies have begun to explore how specific members of the root microbiome act to enhance plant growth, we still lack a full understanding of the role of the broader root microbiome in shaping plant stress tolerance. Emphasizing three of the most agriculturally significant abiotic challenges, namely, drought stress, salinity stress, and phosphate stress, this chapter describes our current understanding of the specific mechanisms the root microbiome can employ to help boost plant fitness and summarizes new methods through which the plant root microbiome has been leveraged in agricultural settings to reduce damage from abiotic stresses.