[Genetic diversity among Chinese peanut rhizobia by rep-PCR analysis]

Repetitive sequences(repetitive extragenic palindromic[REP], and enterobacterial repetitive intergenic consensus [ERIC]) with the polymerase chain reaction(PCR) were used to fingerprint pure DNA extracted from 79 bradyrhizobial strains. These strains included 59 peanut rhizobia [Bradyrhizobium sp. (Arachis)] isolated from root nodules of 24 peanut (Arachis hypogaea L) cultivars from 23 sites in 11 provinces in China, 6 peanut rhizobial strains from other nations, and 14 reference strains of other bradyrhizobia. All the strains were clustered at the level of 11%, 2%, and 11, 24 clusters were obtained at the similarity of 50% with REP-PCR and ERIC-PCR fingerprints, respectively. The results showed that significant genomic diversity exists within the peanut rhizobia from China. Also they suggested that there are different distributions of REP and ERIC in genomic DNA of the peanut rhizobia. The combined results, REP plus ERIC data, were found between the both above. The genomic diversity seems not to correlate with their host and geographic origins. Our results supported this technique is a useful tool for genotypic characterization and identification of rhizobia as well as ecological studies.