ISOLATION AND CHARACTERIZATION OF PHOSPHATE SOLUBILIZING BACTERIA FROM RHIZOSPHERE SOILS FOR POTENTIAL USE IN AGRICULTURAL PRACTICES OF SOLANUM MELONGENAPonnaiah Paulraj, Rajeswari Gunaseelan, Antony V. Samrot, Arashidatul Akmar Ismail, Iyappan P., Chandramohan M., Sajna Keeyari Purayil, Pattammadath Sajeesh, Tunasamy Ketharin, Pazhayakath Thevarkattil Mohamed Javad, Hau Zhe Fung and Jenifer Selvarani A.
The ability of some soil microorganisms to convert insoluble forms of phosphorus to an accessible form is crucial in plant growth-promoting bacteria for increasing plant yield. Phosphate Solubilising Bacteria (PSB) as inoculants increases the P uptake by plants. They interact with root region and enhance the plant growth directly or indirectly. In this study, twelve rhizosphere soil samples of Solanum melongena were collected from three different places and characterized the potential PSB which solubilised organic P in Pikovaskaya media, rock phosphate and eggshells and bones was identified. The potential strain was isolated and characterized as Rhizobium sp. This strain was inoculated in rhizosphere to increase the plant growth as well as crop yield. The effect of the PSB on growth of S. melongena seedlings were studied in pot experiment. The plants parameters results showed the highest mean shoot length of S. melongena was achieved by the condition of Rhizobium sp. with eggshells and bones application at 14.00 cm, followed by Rhizobium sp. with Triple Super Phosphate (13.00cm) and finally Rhizobium sp. with Rock Phosphate (11.60cm). Moreover, the chlorophyll content of S. Melongena showed maximum value for the condition of Rhizobium sp. inoculated with eggshells and bones application (6.215mg/g), followed by PSB inoculated with TSP (5.932 mg/g) and finally inoculated with RP (5.214mg/g). So, it can be concluded that rock phosphate simultaneously combined with PSB strain tends to solubilise organic P in the soil as good as TSP and they also can be used as alternative chemical phosphate fertilizer. Besides that, eggshells and bones were used as substitutes of inorganic P to study the ability of PSB to solubilise the inorganic P.