Azotobacter vinellandii SINAz1 Increases Growth and Productivity in Rice under Salinity Stress

Abstract

Background: Azotobacter vinellandii is a soil bacterium which fixes atmospheric nitrogen and provides growth hormones to plant. Locally isolated species can be utilized and efficient bio fertilizers can be prepared. Methods: A nitrogen fixing bacteria was isolated and it was biochemically identified as Azotobacter vinellandii and named as Azotobacter vinellandii SINAz1. The 16s rRNA was isolated and the sequence was submitted to NCBI data base and got the Accession number as MN135308.1. The presence of nif D, nif K and nif H gene was studied by PCR amplification. The nitrogen fixing efficiency of these bacteria was studied in laboratory by acetylene reduction assay (ARA) and also by pot culture experiments. The plant growth promoting (PGP) activities also studied by isolating and estimating the secretion of hormones like IAA, GA3, ABA and zeatin. These bacteria also provide salinity stress (200 mM NaCl) tolerance to rice plant for 15 days as compared with the control. Result: The phenotypic growth and yield of rice crop by the application of these bacteria was studied which found to be significantly better than the control. This novel bacterium can be used as a substitute for the chemically synthesized nitrogen fertilizer for better productivity under normal as well as salinity stress condition.