Phylogenetic tree showing the relationships of Rhizobium leguminosarum bv. trifolii strain WSM597 (shown in blue print) with some of the root nodule bacteria in the order Rhizobiales based on aligned sequences of the 16S rRNA gene (1,307 bp internal region). All sites were informative and there were no gap-containing sites. Phylogenetic analyses were performed using MEGA, version 5.05 . The tree was built using the maximum likelihood method with the General Time Reversible model. Bootstrap analysis  with 500 replicates was performed to assess the support of the clusters. Type strains are indicated with a superscript T. Strains with a genome sequencing project registered in GOLD  are in bold print and the GOLD ID is mentioned after the accession number. Published genomes are designated with an asterisk.