engleski

Genomic fingerprinting of Bradyrhizobium japonicum isolates by RAPD and rep-PCR

Genetic diversity of indigenous Bradyrhizobium japonicum population in Croatia was studied by using different PCR-based fingerprint methods. Characteristic DNA profiles for 20 B. japonicum field isolates and two inoculant strains were obtained using random primers (RAPD) and two sets of repetitive primers (REP- and ERIC-PCR). In comparison with the REP, the ERIC primer set generates fingerprints with a lower level of complexity, but still several specific bands were detected. Different B. japonicum isolates could be more efficiently distinguished by using combined results from REP- and ERIC-PCR. The most polymorphic bands were determined in amplification reactions with four different RAPD primers. Both methods, RAPD and rep-PCR, resulted in identical grouping of strains. Cluster analysis, irrespective of fingerprint method used, revealed that all the isolates could be divided into three major groups. Only different degree of relative similarity between these groups and a minor rearrangement of strains within major groups were determined depending upon the method used. Our results indicate that both RAPD and rep-PCR fingerprinting could effectively distinguish different B. japonicum strains. RAPD fingerprinting proved to be slightly more discriminatory than rep-PCR.

Bradyrhizobium japonicum; indigenous strains; RAPD; rep-PCR

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