Kiloniella antarctica sp. nov., isolated from a polynya of Amundsen Sea in Western Antarctic Sea

Abstract

A taxonomic study was conducted on strain soj2014T, which was isolated from the surface water of a polynya in the Antarctic Sea. Comparative 16S rRNA gene sequence analysis showed that strain soj2014T belongs to the family Kiloniellaceae and is closely related to Kiloniella spongiae MEBiC09566T, 'Kiloniella litopenaei' P1-1T and Kiloniella laminariae LD81T (98.0 %, 97.8 % and 96.2 % 16S rRNA gene sequence similarity, respectively). The DNA？DNA hybridization values between strain soj2014T and closely related strains were below 28.6%. The G+C content of the genomic DNA of strain soj2014T was 45.5 mol%. The predominant cellular fatty acids were summed feature 8 (composed of C18 : 1!6c/C18 : 1!7c, 57.0 %) and summed feature 3 (composed of C16 : 1!6c/C16 : 1!7c, 23.5 %). Strain soj2014T was Gram-stain-negative, slightly curved, spiral-shaped, and motile with a single polar flagellum. The strain grew at 0？30 C (optimum, 25 C), in 1.5？5.1% (w/ v) NaCl (optimum, 2.1？2.4 %) and at pH 5.5？9.5 (optimum, 7.5？8.0). It also had differential carbohydrate utilization traits and enzyme activities compared with closely related strains. Based on these phylogenetic, phenotypic and chemotaxonomic analyses, strain soj2014T represents a distinct species, separable from the reference strains, and is, therefore, proposed as a novel species, Kiloniella antarctica sp. nov. The type strain is soj2014T (=KCTC 42186T=JCM 30386T).