Studies the identification and detection systems for rhizobia and other bacteria based on ribosomal ribonucleic acids (rRNA). Usefulness of rRNA as marker molecules for elucidation of bacterial phylogeny; Sub-groups of the f-subclass of Proteobacteria, of which bacteria of the rhizobial phenotype are members, based on 16S rRNA sequence data; Various kinds of rhizobia related to non-symbiotic and/or non-nitrogen-fixing bacteria.