Salinisphaera dokdonensis sp. nov., isolated from surface seawater.

A Gram-negative, strictly aerobic bacterium, designated CL-ES53(T), was isolated from surface water of the East Sea in Korea. Cells of strain CL-ES53(T) were short rods and motile by means of monopolar flagella. Strain CL-ES53(T) grew with 4-21 % NaCl (optimum 10 %) and at 5-40 degrees C (optimum 25 degrees 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 C(18 : 1)omega7c (42.0 %), C(18 : 1)omega9c (14.8 %) and C(14 : 0) (9.4 %). The genomic DNA G+C content was 64.9 mol%. Analysis of the 16S rRNA gene sequence of strain CL-ES53(T) 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 EPR70(T) (93.8 %). Phylogenetic analyses based on the 16S rRNA gene sequence showed that strain CL-ES53(T) formed a robust cluster with S. shabanensis E1L3A(T). Although the 16S rRNA gene sequence similarity between strain CL-ES53(T) 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-ES53(T) was differentiated from S. shabanensis E1L3A(T) and S. hydrothermalis EPR70(T) on the basis of optimum temperature for growth and certain phenotypic characteristics. The phylogenetic analysis and physiological and chemotaxonomic data show that strain CL-ES53(T) 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-ES53(T) (=KCCM 90064(T) =DSM 19549(T)).