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. str 1401-13, and Thiothrix nivea were determined by 16S rRNA sequence analysis. Fluorescent in situ hybridization with Thioploca-specific oligonucleotide probes was used to substantiate the sequences of T. araucae and T. chileae. All three Thioploca species form a monophyletic group. They are affiliated with Beggiatoa alba and Beggiatoa sp. str 1401-13. Thioploca and Beggiatoa constitute a new phylogenetic lineage within the gamma-subdivision of the proteobacteria, showing similar genetic diversity as other major groups of gamma- or beta-subdivision sulfur oxidizers. Thiothrix nivea is a member of the gamma proteobacteria, but does not form a monophyletic lineage with Beggiatoa and Thioploca