Development of Abiotic Stress Tolerance in Crops by Plant Growth-Promoting Rhizobacteria (PGPR)

Abstract

Agriculture production was effectively decreased by abiotic and biotic stresses, which affect the plant growth by ion toxicity, hormonal and nutritional imbalance, and physiological and metabolic changes. Plant growth-promoting rhizobacteria (PGPR) are the root-colonizing non-pathogenic bacterium, which helps in plant growth promotion and alleviation of the stress-induced changes to result in the maintenance of agricultural productivity. Plants inoculated with the PGPR provide resistance to various abiotic stresses such as salt, drought, and heavy metal toxicity. Some PGPR strains protect both the biotic and abiotic stresses. In addition, several PGPR contribute to multiple abiotic stress tolerance in plants. PGPR produce phytohormones, siderophores, organic acids, and stress-induced metabolites such as osmotic solutes, prolines, and antioxidant enzymes and up- and downregulates the expression of various stress-responsive genes that provide resistance to the plants under stressful conditions. The use of PGPR is a simple and effective alternative approach to genetic engineering and breeding methods for crop improvement, since breeding and genetic engineering are time-consuming, expensive, and laborious procedures. In this chapter, we described the potential role of PGPR in the abiotic stress tolerance in plants. Moreover, the mechanism of PGPR in drought, salt, and heavy metal stress alleviation was described briefly.