RAPID IDENTIFICATION OF RHIZOBIA BY RESTRICTION-FRAGMENT-LENGTH-POLYMORPHISM ANALYSIS OF PCR-AMPLIFIED 16S RIBOSOMAL-RNA GENES

Forty-eight strains representing the eight recognized Rhizobium specie s, two new Phaseolus bean Rhizobium genomic species, Bradyrhizobium sp p., Agrobacterium spp., and unclassified rhizobia from various host pl ants were examined by restriction fragment length polymorphism (RFLP) analysis of 16S rRNA genes amplified by polymerase chain reaction (PCR ). Twenty-one composite genotypes were obtained from the combined data of the RFLP analysis with nine endonucleases. Species assignments wer e in full agreement with the established taxonomic classification. Est imation from these data of genetic relationships between and within ge nera and species correlated well with previously published data based on DNA-rRNA hybridizations and sequence analysis of 16S rRNA genes. Th is PCR-RFLP method provides a rapid tool for the identification of roo t nodule isolates and the detection of new taxa.