Phylogenetic tree showing the relationships of Mesorhizobium opportunistum WSM2075T with other root nodule bacteria in the order Rhizobiales based on aligned sequences of the 16S rRNA gene (1,290 bp internal region). All positions containing gaps and missing data were eliminated. Phylogenetic analyses were performed using MEGA, version 3.1 . The tree was built using the Maximum-Likelihood method with the General Time Reversible model and bootstrap analysis  with 500 replicates to construct a consensus tree. Type strains are indicated with a superscript T. Brackets after the strain name contain a DNA database accession number and/or a GOLD ID (beginning with the prefix G) for a sequencing project registered in GOLD . Published genomes are indicated with an asterisk.