Phylogenetic tree showing the relationship of Ensifer meliloti 4H41 (shown in bold blue print) to Ensifer spp. and other root nodule bacteria species in the order Rhizobiales, based on aligned sequences of the 16S rRNA gene (1,240 bp internal region). (The species name “Sinorhizobium chiapanecum” has not been validly published.) Azorhizobium caulinodans ORS 571T was used as an outgroup. All sites were informative and there were no gap-containing sites. Phylogenetic analyses were performed using MEGA, version 6 . 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 font and the GOLD ID is provided after the GenBank accession number, where this is available. Finished genomes are indicated with an asterisk.