Plant Growth Promoting Rhizobacteria: Applications and Perspectives In Agriculture

Rhizobacteria that exert beneficial effects on plant growth and development are referred to as plant growth promoting rhizobacteria (PGPR). In recent years, the use of PGPR to promote plant growth has increased in various parts of the world. PGPR can affect plant growth by production and release of secondary metabolites (plant growth regulators/phytohormones/biologically active substances), lessening or preventing deleterious effects of phytopathogenic organisms in the rhizosphere and/or facilitating the availability and uptake of certain nutrients from the root environment. Selection of effective PGPR is the most critical aspect to have maximum benefits from this technology. Researchers are using different approaches for screening rhizobacteria to select effective PGPR including promotion of root/shoot growth under gnotobiotic conditions, in vitro production of plant growth regulators/biologically active substances and assessing of ACC-deaminase activity of the rhizobacteria. However, the combined use of two or more approaches for screening of rhizobacteria could be more useful to select effective PGPR. These screening approaches and practical applications of PGPR in agriculture are the major focus of this review.