Symbiotic Rhizobacteria for Improving of the Agronomic Effectiveness of Phosphate Fertilizers

After nitrogen, phosphorus is the main element for plant growth. Most agricultural soils worldwide are deficient in phosphorus and therefore require a contribution of phosphorus for the plant needs. There is a continuing need to improve soil fertility, to increase yields and agricultural productivity. During the application of phosphate fertilizers, soluble phosphorus assimilated by plants is rare because of its precipitation and then become unavailable to the plant. Rhizospheric bacteria including the plant growth promoting rhizobacteria (PGPR) are of growing interest for their potential role in improving soil fertility and enhancing an increase of crop yields and their nutrients contents. These bacteria make the insoluble phosphorus in soluble forms during the application of phosphate fertilizers and make the phosphorus available to the plant. This work gives a review of methodology and techniques used for the research of phosphate solubilization bacteria (PSB), their molecular characterization and the biochemical mechanisms and genes tools involved in solubilization of phosphate and their relationships with symbiotic plants.