FIG. 1.

16S rRNA-based phylogenetic tree of the “Rhodocyclales” and selected type strains of other betaproteobacterial orders. The consensus tree is based on maximum-likelihood analysis (AxML) performed with a 50% conservation filter for the “Betaproteobacteria.” The bar indicates 10% estimated sequence divergence. Polytomic nodes connect branches for which a relative order could not be determined unambiguously by applying neighbor-joining, maximum-parsimony, and maximum-likelihood treeing methods. Numbers at branches indicate percent parsimony bootstrap values. Branches without numbers had bootstrap values of less than 50%. The minimum 16S rRNA sequence similarity for each “Rhodocyclales” lineage is shown.