Plant–PGPR Interactions for Pest and Disease Resistance in Sustainable Agriculture

Plant-growth-promoting rhizobacteria (PGPR) are naturally occurring bacteria that colonize plant roots and benefit of plant system. Inoculation of crop plants with certain strains of PGPR at an early stage of development improves biomass production through direct effects on root and shoot growth. They help in increasing nitrogen fixation in legumes; help in promoting free-living nitrogen-fixing bacteria; increase supply of other nutrients, such as phosphorus, sulfur, iron, and copper; produce plant hormones; enhance other beneficial bacteria or fungi; control fungal and bacterial diseases; and help in controlling insect pests. During the interaction of PGPR with plant, it induces defense mechanisms against pest and diseases. The aim of this review is to describe PGPR modes of action and discuss with interaction of plants at molecular level for PGPR use in agriculture.