Plant Growth Promoting Rhizobacteria (PGPR)

  PGPR are beneficial bacteria, which are ready to establish a symbiotic or nonsymbiotic association with plants within the rhizosphere. Rhizobium is the most important PGPR, which is able to develop a symbiotic association with its specific host plant and increase its growth and yield by biologically fixing atmospheric N. Rhizobacteria are root-associated bacteria that form symbiotic relationships with many plants. The name comes from the Greek rhiza, meaning root. Though parasitic sorts of rhizobacteria exist, the term usually refers to bacteria that form a relationship beneficial for both parties. Bacteria that colonize plant roots and promote plant growth are mentioned as plant growth-promoting rhizobacteria. Their effects can occur via local antagonism to soil-borne pathogens or by induction of systemic resistance against pathogens throughout the whole plant. Bacteria enjoy the plant nutrients provided by the roots, but plants can enjoy their rhizobacteria also . Bacteria referred to as Plant Growth-Promoting Rhizobacteria (PGPR) are diverse and represent a good range of phyla. Plant growth-promoting rhizobacteria (PGPRs) are the beneficial rhizosphere inhabiting soil bacteria (Kloepper and Schroth, 1978). Depending on their association with the host plant, there are two categories of PGPRs: intracellular and extracellular. Plant growth-promoting rhizobacteria are the rhizosphere bacteria, which may ameliorate plant growth. These microorganisms are ready to enhance the recycling of plant nutrients and reduce the utilization of chemical fertilization.