Rheinheimera japonica sp. nov., a novel bacterium with antimicrobial activity from seashore sediments of the Sea of Japan

Abstract

Two gram-negative, aerobic, brown-pigmented, motile rod-shaped bacteria KMM 9512 and KMM 9513T were isolated from a sediment sample collected from the Sea of Japan seashore, Russia. On the basis of the 16S rRNA gene sequence analysis, novel strains KMM 9512 and KMM 9513T positioned within the genus Rheinheimera (class Gammaproteobacteria) as a separate subline adjacent to Rheinheimerabaltica DSM 14885T sharing highest gene sequence similarities of 98.6–97.6 % to their closest phylogenetic relatives, Rheinheimera muenzenbergensis LMG 27269T, R.baltica DSM 14885T, Rheinheimeraaquimaris JCM 14331T, Rheinheimera nanhaiensis KACC 14030T, and Rheinheimerapacifica KMM 1406T. Strains KMM 9512 and KMM 9513T belong to the same separate genospecies on the basis of the 16S rRNA gene sequence similarity (99.8 %) and their DNA relatedness to each other (89 %) and to closely related Rheinheimera species (25–53 %). The major isoprenoid quinone was Q-8, polar lipids consisted of phosphatidylserine, phosphatidylglycerol, phosphatidylethanolamine, unknown aminolipids, unknown aminophospholipids, unknown phospholipids, and unknown lipids, and major fatty acid were C16:0, C16:1ω7c, C17:1ω8c, C12:0 3-OH followed by C17:0 and C18:1ω7c in both strains. Strains KMM 9512 and KMM 9513T revealed a remarkable antagonistic activity toward a number of gram-positive and gram-negative microorganisms. On the basis of phylogenetic analysis, DNA–DNA hybridization results, and phenotypic differences, strains KMM 9512 and KMM 9513T are proposed to be classified as a novel species of the genus Rheinheimera, Rheinheimera japonica sp. nov. The type strain of this species is KMM 9513T = NRIC 0918T.