Adansonian analysis of the Rhizobiaceae.

Abstract

SUMMARY: One hundred and ninety-one coded features of 21 strains of the genera Rhizobium, 18 of Agrobacterium, 11 of Chromobacterium, selected strains of Vibrio cholerae, Flavobacterium, and other representative strains of the families Enterobacteriaceae and Pseudomonadaceae were subjected to Adansonian analysis, with the use of a high-speed computer for the establishment of Similarity (S) and Matching (M) coefficients and for the sorting of the strains into taxonomic clusters. From the frequency of occurrence of features computed for each of the clusters, tables were prepared which provided correlated characteristics suitable for the description of the clusters. Hypothetical median organisms were also computed for each of the clusters and actual strains were selected as neotypes for the new genera, Rhizobium and Phytomyxa. The genus Rhizobium includes the fast-growing rhizobia and the agrobacteria and contains at least four species: R. meliloti, R. legumino-sarum, R. radiobacter, R. rubi. The genus Phytomyxa is reserved for the slow-growing rhizobia which have been placed in the species R. japonicum. Agro-bacterium gypsophilae and A. pseudotsugae are removed from both Rhizobium and Phytomyxa as defined in this study. The lack of significantly high inter-generic relationships amongst the members of the family Rhizobiaceae suggest revaluation of the family structure. From the results obtained here, the genera Rhizobium and Phytomyxa appear more closely related to the members of the Pseudomonadaceae.