Numerical analysis of Astragalus cicer microsymbionts

Thirty-seven rhizobium strains, isolated from root nodules of Astragalus cicer (L.) (cicer milkvetch) deriving from different geographic regions, were compared with the representative strains of the known rhizobial species and genera by numerical analysis of phenotypic characteristics. Our results indicated that Astragalus cicer rhizobia were related to the bacteria of Mesorhizobium species and formed two major phena. One phenon, localized on Mesorhizobium loti branch, contained strains from Poland. Another cluster, placed in the vicinity of M. tianshanense, M. mediterraneum, M. ciceri, and M. huakuii, comprised cicer milkvetch nodule isolates from Canada, Ukraine, and one strain from Poland. The relationship of Astragalus cicer microsymbionts to bacteria of the Mesorhizobium species was also supported by phage typing.