Genetic diversity of plant growth-promoting rhizobia isolated from a medicinal legume, Mucuna pruriens Linn.

Genetic diversity of five Sinorhizobia from a medicinal legume, i.e. Mucuna pruriens was investigated using ARDRA analysis. All five strains were isolated on YEMA which showed pink colour on CrYEMA, tolerated 2% NaCl and precipitated calcium glycerophosphate. The isolates were analysed using restriction patterns produced by amplified DNA coding for 16S rDNA (ARDRA) and were placed into two genotypes. All five isolates belonged to a single cluster. A distinct similarity was observed between the RAPD and 16S rDNA RFLP analysis. Nodulation and nitrogen-fixing abilities of the strains were confirmed by amplification of 500bp nodC and 781bp nifH fragments respectively. All five isolates solubilized inorganic insoluble phosphate, produced IAA and did not produce HCN. Strains MPR3 and MPR4 produced siderophore and inhibited fungal pathogens, Macrophomina phaseolina and Fusarium oxysporum. The study showed that there is considerable homogeneity amongst M. pruriens root-nodule isolates.