Exilibacterium tricleocarpae gen. nov., sp. nov., a marine bacterium from coralline algae Tricleocarpa sp.

Abstract

A Gram-stain-negative, non-spore-forming, aerobic, curved rod-shaped bacterium, designed strain R142T, was isolated from a coralline algae Tricleocarpa sp. in the Beibu Gulf, China. Optimal growth occurred with 0–0.5 % (w/v) NaCl, at 25 °C and at pH 8. Global alignment based on 16S rRNA gene sequences indicated that strain R142T shared 93.8 % similarity with its closest type strain, Pseudomaricurvus alkylphenolicus KU14GT. Phylogenetic analyses showed that strain R142T forms a distinct branch alongside Maricurvus nonylphenolicus KU41ET, Pseudoteredinibacter isoporae SW-11T, Pseudomaricurvus alkylphenolicus KU14GT, Pseudomaricurvus alcaniphilus MEBiC06469T and Aestuariicella hydrocarbonica SM-6T. The major polar lipids of strain R142T were phosphatidylethanolamine and phosphatidylglycerol. The primary cellular fatty acids were C16 : 0, C16 : 1ω7c, C18 : 1ω7c, C18 : 0 and C14 : 0. The genome DNA G+C ratio was 56.4 mol%. The only detected respiratory quinone was ubiquinone 8. The low 16S rRNA gene sequence similarity and differences in cellular fatty acids readily distinguished strain R142T from all validly published type strains. Strain R142T is therefore suggested to represent a novel species of a new genus, for which the name Exilibacterium tricleocarpae gen. nov., sp. nov. is proposed. The type strain of Exilibacterium tricleocarpae is R142T (=MCCC 1K03816T=KCTC 72138T).