Screening of rhizobacteria isolated from rice (Oryza sativa L.) and chickpea (Cicer arietinum L.) from the paddy fields near Mumbai and exploring their potential

Rhizosphere provides all the necessary nutrients to plants by direct and indirect means. Plant Growth Promoting Rhizobacteria (PGPR) residing in rhizosphere are able to synthesize various metabolic compounds beneficial to plants and carry out different biological processes including Nitrogen fixation and Phosphate solubilization, etc. Current study focuses on gibberellic acid (GA₃) production and Phosphate solubilization. Gibberellic acid is one of the phytohormones responsible for the growth of the plants. Phosphate solubilization property of PGPR aid in the conversion of insoluble Phosphate into more soluble form and make it available to plants. 45 different soil samples were collected from the rhizosphere of rice and chickpea plant each. 319 isolates were obtained from the soil and were screened for Phosphate solubilization and production of gibberellic acid. Solubilization indices (SI) of the isolates were calculated and 10 isolates with maximum SI were screened for quantitative approach. Similar isolates were also screened for gibberellic acid production, both qualitatively and quantitatively. Maximum activity was obtained as 1208.57 |jgP/ml and 82.820 mg/ml for phosphate solubilization and gibberellic acid production respectively. Most potent rhizobacterium was identified as Stenotrophomonas maltophilia using Fatty Acid Methyl Esterase (FAME) analysis. Isolates were also screened for Ammonia production.