Gracilimonas tropica gen. nov., sp. nov., isolated from a Synechococcus culture

Abstract

An irregular, long, rod-shaped marine bacterium, designated CL-CB462T, was isolated from a Synechococcus culture, which was established from surface water from the tropical Pacific Ocean. The physiological and biochemical features, fatty acid profile and phylogenetic position based on 16S rRNA gene sequences were investigated for the novel strain. Phylogenetic analysis of the 16S rRNA gene sequence showed that the closest relatives of strain CL-CB462T were Balneola vulgaris and Balneola alkaliphila. Strain CL-CB462T formed a robust clade with members of the genus Balneola in all phylogenetic trees constructed by three different methods. However, the 16S rRNA gene sequence similarity was very low (91.3-91.5% similarity) and phenotypic and physiological features could clearly differentiate strain CL-CB462T from the genus Balneola. Cells of the novel strain were non-motile and spore-forming. The strain was able to grow at 1-20% (w/v) (optimum of 3-6 %) sea salt concentration, at temperatures of 20-40 °C and between pH 6 and 10. The fatty acids were dominated by 15:0 iso (41.2 %) and 17:1ω9c iso (21.4 %). The DNA G+C content was 42.7 mol%. Based on polyphasic evidence, strain CL-CB462T was considered to represent a new genus. The name Gracilimonas tropica gen. nov., sp. nov. is proposed for the type strain of the type species (CL-CB462T=KCCM 90063T=DSM 19535T). © 2009 IUMS.