Phylogenetic analysis of a novel sulfate-reducing magnetic bacterium, RS-1, demonstrates its membership of the delta-Proteobacteria.

Most of the 16S ribosomal RNA gene of a sulfate-reducing magnetic bacterium, RS-1, was sequenced, and phylogenetic analysis was carried out. The results suggest that RS-1 is a member of the delta-Proteobacteria, and it appears to represent a new genus. RS-1 is the first bacterium reported outside the alpha-Proteobacteria that contains magnetite inclusions. RS-1 therefore disrupts the correlation between the alpha-Proteobacteria and possession of magnetite inclusions, and that between the delta-Proteobacteria and possession of greigite inclusions. The existence of RS-1 also suggests that intracellular magnetite biomineralization is of multiple evolutionary origins.