Genetic diversity of rhizobia isolated from medicinal legumes growing in the sub-Himalayan region of Uttaranchal

Diversity of rhizobia recovered from five medicinal legumes, Trigonella foenum graecum, Abrus precatorius, Mucuna pruriens, Melilotus officinalis and Vicia angustifolia was investigated. Nine bacterial strains isolated on yeast extract mannitol agar (YEMA) and showing tolerance to 2% NaCl were analysed along with reference strains, Bradyrhizobium japonicum SB102, Sinorhizobium meliloti 102F 34 and Rhizobium gallicum R602sp(T) using restriction patterns produced by amplified DNA coding for 16S rDNA (ARDRA) with two enzymes HaeIII and MspI and were placed in six genotypes. Four isolates from Trigonella, i.e. PP1, PP2, PP3 and PP4 were placed in two genotypes; one genotype was closely related to S. meliloti 102F 34 and the other to B. japonicum SB 102. Genetic diversity was also assessed by repetitive PCR using BOX primers, wherein all the isolates were placed in five genotypes. Based on repetitive PCR, isolates from nodules of Trigonella were placed in single genotype. Nitrogen-fixing ability of the isolates was confirmed by amplification of 781 bp nifH fragment in five isolates, PP1, PP2, PP3, PP4 and PP9.