Abstract

An orange-pigmented, oxidase-positive bacterial strain (I-41R45(T)), isolated from the kidney of a black rock cod fish sampled in the Chilean Antarctic was studied in a polyphasic taxonomic investigation. Cells of the isolate were coccoid and stained Gram-negative. A comparison of the 16S rRNA gene sequence of strain I-41R45(T) with sequences of type strains of most closely related Paracoccus species showed highest sequence similarities to Paracoccus hibiscisoli (98.4 %), Paracoccus marcusii (98.3%), Paracoccus haeundaensis and Paracoccus carotinifaciens (both 98.2%). 16S rRNA gene sequence similarities to all other Paracoccus species were below 97%. The draft genome of strain I-41R45(T) had a size of 4.59 Mb with a DNA G+C content of 65.26 mol% and included the prediction and annotation of 4426 coding genes, 1973 protein-coding genes and 46 tRNAs. The fatty acid profile of strain I-41R45(T) consisted mainly of the major fatty acids C-18 : 1 omega 7c/omega 9t/omega 12t and C-18: 0, typical of the genus Paracoccus. DNA-DNA hybridizations between I-41R45(T) and type strains of P. hibiscisoli, P. marcusii and P. haeundaensis resulted in similarity values of 45% (reciprocal 26 %), 66% (reciprocal 61 %), and 29% (reciprocal 36 %), respectively. DNA-DNA hybridization results, together with the differentiating biochemical and chemotaxonomic properties, showed that strain I-41R45(T) represents a novel Paracoccus species, for which the name Paracoccus nototheniae sp. nov. (type strain I-41R45(T)=CCM 8875(T)=CIP 111632(T)), is proposed.