Genetic Characterization of Rhizobia Associated with Horse Gram [Macrotyloma uniflorum (Lam.) Verdc.] Based on RAPD and RFLP

Aim: To genetically characterize rhizobia collected from the root nodules of Horse gram plants grown in different soil samples by using the methods RAPD and RFLP.

Place and Duration of Study: Root nodules were collected from the plants grown in soil samples collected from different regions in Andhra Pradesh and Telangana states, India.

Methodology: These isolates were characterized by two RAPD primers RPO4 and RPO5 of 10 nucleotide length. The PCR amplicons were purified by Qiaquick® PCR purification kit and digested by three restriction endonucleases i.e., TaqI, HpaII and AluI.

Results: The RAPD profiles and restriction analysis of 16S rRNA gene with the three endonucleases showed high polymorphism. RAPD and RFLP analysis of these 32 horse gram rhizobia showed that these isolates fall into four major clusters. The first clusters of both dendrograms from RAPD and RFLP contained the majority of the rhizobial isolates.

Conclusion: From this, it is clear that RAPD and RFLP may play an important role if applied, to know the genetic diversity of rhizobia. High genetic diversity was observed among the horse gram rhizobial population and very few of the bacteria were considered to be identical. It clearly shows that the horse gram rhizobia are phylogenetically distinct.