Intra- and Intergeneric Similarities of Agrobacterium Ribosomal Ribonucleic Acid Cistrons

作者：Jonas De Smedt, J. De Ley · 发表于：International Journal of Systematic Bacteriology · 年份：1977 · DOI：10.1099/00207713-27-3-222 · 被引用次数：130 · 研究领域：Microbial Community Ecology and Physiology、Enzyme Production and Characterization、Plant-Microbe Interactions and Immunity

We prepared hybrids between 14C-labeled ribosomal ribonucleic acid (rRNA) from either Agrobacterium tumefaciens ICPB TT111 or A. rhizogenes ICPB TR7, and deoxyribonucleic acid (DNA) from a great variety of reference gramnegative and gram-positive bacteria. Each hybrid was described by (i) its T m(e) the temperature at which 50% of the hybrid was denatured, and (ii) percentage of rRNA binding, i.e., micrograms of 14C-labeled rRNA duplexed per 100 μg of filter-fixed DNA. Each taxon occupied a definite area on the rRNA similarity map. The size and shape of this area depended on the phenotypic and genetic heterogeneity of the taxon. There appeared to be a correlation between Tm(e) of the heterologous hybrids and the overall phenotypic similarities of the organisms and taxa involved. Tm(e) values above 65°C were taxonomically most meaningful. DNA: rRNA hybridizations condensed all strains from a genus in one narrow cluster; the method had little resolution to distinguish species within a genus, but it seemed to be a very useful approach to detect remote relationships at the inter- and suprageneric level, for taxonomic and identification purposes. The hybrid parameters of Azotomonas fluorescens, Mycoplana bullata, Mycoplana dimorpha, Phyllobacterium, two misnamed “Chromobacterium lividum” strains from leaf-nodulating plants, two misnamed agrobacteria from the Baltic Sea, and a few misnamed “Achromobacter” strains were all in the vicinity of Agrobacterium and Rhizobium. We suggest t...