Opitutus terrae gen. nov., sp. nov., to accommodate novel strains of the division 'Verrucomicrobia' isolated from rice paddy soil

Abstract

Three strains of obligately anaerobic bacteria were isolated from rice paddy soil microcosms. Comparative analysis of the 16S rRNA genes showed that these novel isolates have identical gene sequences and are members of the division 'Verrucomicrobia'. The novel strains are phenotypically and phylogenetically distinct from species described previously. One strain, PB90-1T, was characterized in more detail. The cells are cocci and are motile by means of a flagellum. Catalase and oxidase activities are absent. Growth-supporting substrates include mono-, di- and polysaccharides, while alcohols, amino acids and organic acids do not support growth. Propionate and acetate are the major end-products of fermentation. Nitrate is reduced to nitrite, but other external electron acceptors are not utilized. The G+C content of the genomic DNA is 74 mol%. This strain represents a taxon that has not yet been formally recognized, for which the name Opitutus terrae gen. nov., sp. nov. is proposed. The type strain is PB90-1T (= DSM 11246T).