EXPLORING PLANT GROWTH-PROMOTING RHIZOBACTERIAL TRAITS IN THE RHIZOSPHERIC SOIL OF PERSEA BOMBYCINA

The rhizosphere is the region of soil that is influenced by root secretions and associated soil microorganisms. Plant growth promotingrhizobacteria (PGPR) are a heterogeneous group of bacteria found in the rhizosphere . Here, an attempt has been made to screen and identify PGPR traits in bacteria isolated and characterized from Perseabombycinarhizospheric soils. Samples were collected from rhizosphere of Som (Perseabombycina) growing in the Regional Botanical Garden, Department of Botany, Gauhati University, Guwahati. 14 pure cultures were obtained in solid Nutient Agar Media. For in vitro screening of isolates for their PGP activities, tests include Indole Acetic Acid Test, quantitative analysis of IAA, production of ammonia (NH3), production of hydrogen cyanide (HCN). Isolates were screened on Pikovskaya’s agar plates for phosphate solubilization. The test isolates gave a positive result towards Gram’s staining reaction. The 14 isolates were able to produce IAA as well as positive for Phosphate solubilization and Ammonia Production whereas negative for Cyanide production. With the addition of tryptophan from 50 to 500 µg/ml the production of IAA was increased. This study will facilitate accurate identification of the bacterial types that harbour PGPR traits essential in combating foliar fungal pathogens of Perseabombycina and in sight an immunological response in the plants (Perseabombycina), thereby enhancing their capability to overcome fungal diseases