The close phylogenetic relationship of Nitrobacter and Rhodopseudomonas palustris.

The phylogenetic position of Nitrobacter winogradskyi and two other nitrite-oxidizing bacteria was elucidated comparing oligonucleotides of the 16S ribosomal RNA. Nitrobacter winogradskyi and the Nitrobacter isolate 'Yukatan' are genetically nearly identical; Nitrobacter isolate X14 is more distantly related. Phylogenetically, Nitrobacter is a member of a group of purple non-sulfur bacteria that is defined by various species of Rhodopseudomonas, Rhodomicrobium vannielii, Rhodospirillum rubum and their non-phototrophic relatives. Nitrobacter shares a high sequence similarity to Rhodopseudomonas palustris. These findings are in accord with several common taxonomic characteristics, and in addition support the conversion hypothesis for the origin of this group of chemolithotrophic bacteria. [ABSTRACT FROM AUTHOR]