Phylogenetic positions of the novel strain SO-S41 and its close relatives within the class Alphaproteobacteria. The tree was constructed by using the neighbor-joining method. Scale bar indicates 0.05 substitutions per nucleotide position. Nodes with bootstrap values of >50%, >75%, and >90% are shown as black circles, gray circles, and open circles, respectively. Three different sequences (Vibrio chagasii [accession no. AJ316199], Vibrio harveyi [accession no. EU130475], and Escherichia coli [accession no. EU014689]) of valid species within the Gammaproteobacteria were used as the outgroup. EBPR, enhanced biological phosphorus removal. Accession numbers are shown in parentheses next to the organism descriptions in the novel order-level lineage group.