PHYLOGENY OF THIOPLOCA AND RELATED FILAMENTOUS SULFIDE-OXIDIZING BACTERIA

The phylogenetic relationships of three Thioploca species, T. araucae, T. chileae and T. inguica, as well as Beggiatoa alba, Beggiatoa sp. s tr 1401-13, and Thiothrix nivea were determined by 16S rRNA sequence a nalysis. Fluorescent in situ hybridization with Thioploca-specific oli gonucleotide probes was used to substantiate the sequences of T. arauc ae and T. chileae. All three Thioploca species form a monophyletic gro up. They are affiliated with Beggiatoa alba and Beggiatoa sp. str 1401 -13. Thioploca and Beggiatoa constitute a new phylogenetic lineage wit hin the gamma-subdivision of the proteobacteria, showing similar genet ic diversity as other major groups of gamma- or beta-subdivision sulfu r oxidizers. Thiothrix nivea is a member of the gamma proteobacteria, but does not form a monophyletic lineage with Beggiatoa and Thioploca.