Horticoccus luteus gen. nov., sp. nov., A Novel Member of the Phylum Verrucomicrobia Isolated from a Dichlorodiphenyltrichloroethane (DDT)-Contaminated Orchard Soil.

Abstract

Strain KSB-15T was isolated from an orchard soil that had been contaminated with the insecticide dichlorodiphenyltrichloroethane for about 60years. The 16S rRNA gene sequence of this strain showed the highest sequence similarities with those of Oleiharenicola alkalitolerans NVTT (95.3%), Opitutus terrae PB90-1T (94.8%), and Oleiharenicola lentus TWA-58T (94.7%) among type strains, which are members of the family Opitutaceae within the phylum Verrucomicrobia. Strain KSB-15T was an obligate aerobe, Gram-negative, non-motile, coccoid or short rod with the cellular dimensions of 0.37-0.62μm width and 0.43-0.72μm length. The strain grew at temperatures between 15-37°C (optimum, 25°C), at a pH range of 5.0-11.0 (optimum, pH 6.0), and at a NaCl concentration of 0-3% (w/v) (optimum, 0%). It contained menaquinone-7 (MK-7) as the major isoprenoid quinone (94.1%), and iso-C15:0 (34.9%) and anteiso-C15:0 (29.0%) as the two major fatty acids. The genome of strain KSB-15T was composed of one chromosome with a total size of 4,320,198bp, a G + C content of 64.3%, 3,393 coding genes (CDS), 14 pseudogenes, and 52 RNA genes. The OrthoANIu values, In silico DDH values and average amino acid identities between strain KSB-15T and the members of the family Opitutaceae were 71.6 ~ 73.0%, 19.0 ~ 19.9%, and 55.9 ~ 62.0%, respectively. On the basis of our polyphasic taxonomic study, we conclude that strain KSB-15T should be classified as a novel genus of the family Opitutaceae, for which the name Horticcoccus luteus gen. nov., sp. nov. is proposed.The type strain is KSB-15T (= KACC 22271T = DSM 113638T).