Genetic basis of enterobacterial repetitive intergenic consensus (ERIC)-PCR fingerprint pattern in Sinorhizobium meliloti and identification of S. meliloti employing PCR primers derived from an ERIC-PCR fragment.

The enterobacterial repetitive intergenic consensus (ERIC)-PCR method was employed to generate genomic amplification products of Sinorhizobium meliloti strain 2011. Eleven distinctive PCR fragments obtained in PCR reactions by using the ERIC2 primer were cloned and their partial or complete nucleotide sequences established. DNA sequences that extended past the ERIC2 primer region were not conserved among the 11 PCR fragments and showed no sequence similarity to the enterobacterial ERIC consensus sequence. Thus, repetitive ERIC or ERIC-like sequences seem not to be an integral part of the S. meliloti genome. An amplification product of S. meliloti 2011 was identified which was present in S. meliloti strains but absent in other rhizobial species. Based on the nucleotide sequence information, a pair of PCR primers was designed and used for PCR amplification of sequences of S. meliloti laboratory strains 2011, L5-30, AK631 and 102F34. Nucleotide sequence analysis of the amplification products revealed a 100% DNA sequence conservation. Database searches showed that the DNA fragment putatively encodes the C-terminal part of a protein displaying similarity to 2-hydroxyacid dehydrogenases of various organisms. The newly designed PCR primers should be useful for the rapid identification of S. meliloti isolates.