Properties of Rhizobium leguminosarum isolated from various regions of Morocco.
Twenty-eight isolates of Rhizobium leguminosarum capable of nodulating broad-bean (Vicia faba L. var. major) were collected throughout Morocco and characterized by using morphological, physiological, biochemical and serological tests. The properties of isolates from within a given climatic zone varied as much as the properties of isolates from different zones. The isolates were adapted to desiccation, but were not adapted to temperatures higher than 37 degrees C. A high degree of heterogeneity was detected among the somatic antigens of the isolates. Utilization of 39 carbon sources and subsequent acidification during growth on these substrates were tested using a commercial microbiological identification system for Enterobacteriaceae. The isolates used a wide variety of carbonaceous compounds for growth. The degree of relatedness among isolates was analysed by computer using 163 features. Computer analysis segregated the isolates into 2 main clusters and 5 singletons. Members of one cluster preferred a slightly acidic pH for growth while the members of the other cluster had a greater metabolic versatility.