Role of plant growth–promoting rhizobacteria in mitigation of heavy metals toxicity to Oryza sativa L.

Abstract Microbes are widely used in the enhancement of plant growth, yield, and nutrient uptake over a long period of time. Apart from biological control, microbes are also known to play a key role in the functioning of plant growth by changing their physiology and metabolism. Recently, intervention of microbes in the improvement of nutrient uptake by plant has gained momentum in the research field. Heavy metal contamination from different sources, such as agricultural practices or burning of fossil fuels, affects the microbial population density and physicochemical parameters of soil leading to the formation of unfertile soil. Plant growth–promoting rhizobacteria (PGPR) are the rhizosphere bacteria, which can ameliorate plant growth by interacting mutually with it. Rice (Oryza sativa L.) is the most important cereal of the world and is the major staple food for the peoples of Asia, Africa, and Latin America. Present rice production management strategies mainly focus on the enormous use of synthetic chemical fertilizers and pesticides for enhancing the per hectare yield of the crop. Persistent and injudicious use of these chemicals including heavy metals has a toxic effect on nontarget microorganisms of the soil and causes undesirable changes in the environment. The use of PGPR as a biological approach for the amelioration of heavy metals toxicity to crop management in place of synthetic chemicals is ecologically sustainable for the environment. Moreover, the biological approach has a great potential in supplying plant nutrition and biocontrol of phytopathogens which eventually will lead to sustainable rice production. Among the different beneficial microflora, the PGPR promotes plant growth, and thereby is capable of affecting the growth and yield of numerous plant species of agronomic and ecological significance including O. sativa L. This chapter highlights the role of PGPR in the amelioration of heavy metals toxicity to rice and soil–nutrient dynamics.