Quadrisphaera setariae sp. nov., polyphosphate-accumulating bacterium occurring as tetrad or aggregate cocci and isolated from Setaria viridis

A Gram-stain-positive, orange-pigmented, aerobic, cocci (occurring in tetrads), non-spore-forming, non-motile bacterium, designated as DD2A^T, was isolated from Setaria viridis collected at Dongguk University, Republic of Korea. Phylogenetic analysis based on the 16S rRNA gene revealed that strain DD2A^T was most closely related to type strains of the genus Quadrisphaera. Strain DD2A^T showed the highest 16S rRNA gene sequence similarities to Quadrisphaera oryzae TBRC 8486^T (99.4%) and Quadri-sphaera granulorum JCM 16010^T (98.8%). Strain DD2A^T also showed auto-aggregation ability. The digital DNA–DNA hybridization values between strain DD2A^T and the reference strains, Q. oryzae TBRC 8486^T and Q. granulorum JCM 16010^T were 31.1 and 27.4%, respectively. The average nucleotide identity values between strain DD2A^T and Q. oryzae TBRC 8486^T and Q. granulorum JCM 16010^T were 86.3 and 84.1%, respectively. The major polar lipids of strain DD2A^T were diphosphatidylglycerol and phos-phatidylglycerol. The major cellular fatty acid of strain DD2A^T was anteiso-C_15:0 . The cell-wall peptidoglycan contained meso-diaminopimelic acid (which is a diagnostic cell-wall diamino acid), alanine and glutamic acid. The respiratory quinones was found to be menaquinone-8. The DNA G+C content of strain DD2A^T was 74.8 mol%. On the basis of the findings of genotypic, phenotypic, chemotaxonomic and phylogenetic analyses, strain DD2A^T was considered to represent a novel member in the genus Quadrisphaera, for which the name Quadrisphaera setariae sp. nov. is proposed. The type strain of Quadrisphaera setariae is DD2A^T (=KACC 21165^T=NBRC 113770^T).