Journal of Pure and Applied MicrobiologyVol. 9 No. 4

Molecular Characterization of Nif Genes of Diazotrophs from Different Rice Production Systems in Tamil Nadu

S. Kanimoli*, M. Karthik and K. Kumar

Department of Agricultural Microbiology, TNAU, Coimbatore - 641003, India.

Received on 21 April 2015 and accepted on 20 July 2015



Heterotrophic diazotrophs were isolated from rhizosphere of rice grown in different locations in Tamil Nadu. The selected diazotrophic bacterial colonies were characterized by cell shape, morphology, Gram reaction and other biochemical tests for their tentative identification. A total of hundred and ten isolates obtained were subjected to acetylene reduction assay (ARA) and ninety eight isolates recorded significant amount of nitrogenase activity.The authenticated diazotrophic isolates from rice rhizosphere were screened for the presence of nif H gene by detection of partial amplification of nif H gene. The universal primers nif Hb1 and CDHP nif 723R, which could amplify 550 bp, were used for screening the isolates by PCR amplification.The nif H amplification could be clearly detected in all the 9 isolates from rice rhizosphere viz., DeLTP2, AbLTP2, AsLC1I, AbSKN, PsSAK2, BeSC2S2, AbAA1A2, PsAKK3, DeATM3.

Keywords : Diazotrophs, Acetylene Reduction Assay, nif H, rice rhizosphere, PCR.