Salinisphaera dokdonensis sp. nov., isolated from surface seawater

Abstract

A Gram-negative, strictly aerobic bacterium, designated CL-ES53T, was isolated from surface water of the East Sea in Korea. Cells of strain CL-ES53T were short rods and motile by means of monopolar flagella. Strain CL-ES53T grew with 4–21 % NaCl (optimum 10 %) and at 5–40 °C (optimum 25 °C) and pH 5.2–8.8 (optimum pH 6.3–7.2). The major isoprenoid quinone was Q-8. The major fatty acids were C18 : 1 ω7c (42.0 %), C18 : 1 ω9c (14.8 %) and C14 : 0 (9.4 %). The genomic DNA G+C content was 64.9 mol%. Analysis of the 16S rRNA gene sequence of strain CL-ES53T revealed that it was a member of the genus Salinisphaera and most closely related to Salinisphaera shabanensis E1L3A T (96.9 % sequence similarity) and Salinisphaera hydrothermalis EPR70T (93.8 %). Phylogenetic analyses based on the 16S rRNA gene sequence showed that strain CL-ES53T formed a robust cluster with S. shabanensis E1L3A T. Although the 16S rRNA gene sequence similarity between strain CL-ES53T and S. shabanensis E1L3A T was rather high (96.9 %), DNA–DNA relatedness between these strains was 12 %, suggesting that they represent genomically distinct species. Strain CL-ES53T was differentiated from S. shabanensis E1L3A T and S. hydrothermalis EPR70T on the basis of optimum temperature for growth and certain phenotypic characteristics. The phylogenetic analysis and physiological and chemotaxonomic data show that strain CL-ES53T should be classified in the genus Salinisphaera within a novel species, for which the name Salinisphaera dokdonensis sp. nov. is proposed. The type strain is CL-ES53T (=KCCM 90064T =DSM 19549T).