Thalassobacter Stenotrophicus Macian Et Al. 2005 is a Later Synonym of Jannaschia Cystaugens Adachi Et Al. 2004, with Emended Description of the Genus Thalassobacter

The type strains of Jannaschia cystaugens (LMG 22015(T)) and Thalassobacter stenotrophicus (CECT 5294(T)) were analysed by means of genomic DNA-DNA hybridization, comparison of 16S rRNA gene sequences and phenotypic properties determined under the same methodological conditions. J. cystaugens LMG 22015(T) showed DNA-DNA relatedness levels of 72% when hybridized with the genomic DNA of T. stenotrophicus CECT 5294(T). Sequence comparisons revealed that the 16S rRNA genes of the two strains had a similarity of 99.8%. The cellular fatty acid and polar lipid compositions of the two strains and their DNA mol% G+C contents were almost identical. Bacteriochlorophyll a (Bchl a) and polyhydroxybutyrate were produced by both strains under the same culture conditions. Their closest phylogenetic neighbours were Jannaschia helgolandensis and Jannaschia rubra; however, the low sequence similarity values (95.7-95.9%) and several important differences in phenotypic traits (ionic requirements, Bchl a production and polar lipids) support the distinction between the genera Thalassobacter and Jannaschia. Thus, we propose the unification of J. cystaugens (LMG 22015(T)) and T. stenotrophicus (CECT 5294(T)) as Thalassobacter stenotrophicus (type strain, CECT 5294(T)=DSM 16310(T)). An emended description of the genus Thalassobacter is also presented.