Thalassococcus lentus sp. nov., an alphaproteobacterium isolated from seawater of a seaweed farm

A Gram-negative, non-motile and rod- or ovoid-shaped bacterial strain, designated YCS-24(T), was isolated from seawater of a seaweed farm in the South Sea, South Korea. Strain YCS-24(T) grew optimally at 25-28 °C, at pH 7.0-7.5 and in the presence of 2 % (w/v) NaCl. Strain YCS-24(T) exhibited the highest 16S rRNA gene sequence similarity values of 97.5 and 97.1 % to the type strains of Thalassobius maritimus and Thalassococcus halodurans, respectively. The neighbour-joining, maximum-likelihood and maximum-parsimony phylogenetic trees based on 16S rRNA gene sequences revealed that strain YCS-24(T) clustered with the type strain of T. halodurans. The DNA G+C content of strain YCS-24(T) was 58.0 mol% and its DNA-DNA relatedness values with T. halodurans JCM 13833(T) and T. maritimus GSW-M6(T) were 17 ± 6.2 and 23 ± 9.2 %, respectively. The predominant ubiquinone found in strain YCS-24(T) was Q-10 and the predominant fatty acid of strain YCS-24(T) was C(18:1) ω7c. The major polar lipids of strain YCS-24(T) were phosphatidylcholine, phosphatidylglycerol, one unidentified aminolipid and one unidentified lipid. Differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, demonstrated that strain YCS-24(T) is distinguished from T. halodurans. On the basis of the data presented, strain YCS-24(T) (= KCTC 32084(T) = CCUG 62791(T)) represents a novel species of the genus Thalassococcus, for which the name Thalassococcus lentus sp. nov. is proposed.