Plant Growth-Promoting Rhizobacteria (PGPR) in Plant Productivity and Protection

Rhizobacteria are found in the rhizosphere (the area directly surrounding a root that is influenced by plant root exudates) of plants and are beneficial for plant development, and hence, are also known as plant growth-promoting rhizobacteria (PGPR). They promote plant growth by increasing the availability of nutrients, increasing the uptake of nitrogen, phosphorus and other minerals, which are known as trace elements in the plant habitat. PGPR help plants directly by secreting phytohormones and some other plant growth-promoting substances and are used as biofertilizers. PGPR also protect plants against pathogens by exploiting their antagonistic potential. They also induce plant-mediated systematic resistance against aboveground microbial pathogens and chewing insects. Pre-plant bacterisation is a plant-protection strategy through delivery of beneficial endophytic bacteria. The use of PGPR as a biocontrol agent has become an effective method of plant protection. In the rhizospheric environment, roots are the primary site of interaction between a plant and microbes. Some species of PGPR help plants by exploring root growth for their stability in stressed conditions.