The Application of Computer Techniques to the Taxonomy of the Root-nodule Bacteria of Legumes

Abstract

The application of computer technics to study a group of organisms comprising 83 strains of the genus Rhizobium and 38 strains belonging to the genera Agrobacterium, Chromobacterium, Beijerinckia and Bacillus is described. One hundred different features including vitamin, carbohydrate and nitrogen nutrition, antibiotic sensitivities, morphological and colonial characteristics and infective attributes were used to determine the relationships between these organisms. Members of the genera Chromobacterium, Bacillus and Beijerinckia showed little affinity with the other species studied, or with each other. The results obtained for the genus Rhizobium indicate the need for major taxonomic changes. These changes would include: the consolidation of R. trifolii, R. leguminosarum and R. phaseoli into a single species, R. leguminosarum. The consolidation of A. radiobacter and A. tumefaciens and their inclusion as R. radiobacter in the genus Rhizobium. The creation of a new genus Phytomyxa to contain strains of slow-growing root-nodule bacteria is also proposed.