Characterization of Azotobacter beijerinckii for PGP properties isolated from tomato rhizosphere of Darjeeling Hills

Abstract

The rhizosphere soil is the habitat of a various kind of microorganisms that play a key role in the enhancement of plant growth. The present study was carried out to screen the abundance of free-living dinitrogen-fixing microorganisms from the tomato rhizosphere of Darjeeling Hills. The bacteria that could fix nitrogen from the atmosphere and grow on media devoid of nitrogen were isolated. One of the potent strains was selected and identified as Azotobacter beijerinckii through molecular characterization using 16S rRNA homology at NCMR-NCCS, Pune. In-vitro production of IAA was 27 (?g/mL), Gibberellic acid was 48 (?g/mL) and the Phosphate solubilization index (SI) was 2.86. The plant growth promotion test was performed on rice seeds using the strain. The results showed that the % increase in germination over control was 7.52%.