Phosphorus Solubilizing Bacteria from Tea Soils and their Phosphate Solubilizing Abilities

The capability of phosphate solubilizing bacteria (PSB) to mineralize phosphate to a plant accessible form is an important way to increase plant yield. In this study, isolation, screening and characterization of 11 strains PSB from tea rhizospheric soil of India were carried out. Mineral P solubilization (MPS) activities of all isolates were evaluated on bacterial growth medium supplemented with four inorganic and five organic P sources. Besides, molecular identification of 11 isolates was executed by 16S rDNA sequencing. While nine isolates belonged to genus Burkholderia, only two belonged to Bacillus. MPS activity of all the strains was associated with a release of organic acids and a drop in the pH of the growth medium. The inverse relationship observed between the pH and soluble-P concentration indicated that organic acid production by these PSB strains plays a significant role in the acidification of the medium facilitating the P solubilization. The results also highlighted the synergistic effect of using PSB strains in combination with rock phosphate. Identification and characterization of potential soil PSB for the effective tea growth expand the range of phosphate solubilizers available for field application of tea crop.