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 R142^T, 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 R142^T shared 93.8 % similarity with its closest type strain, Pseudomaricurvus alkylphenolicus KU14G^T. Phylogenetic analyses showed that strain R142^T forms a distinct branch alongside Maricurvus nonylphenolicus KU41E^T, Pseudoteredinibacter isoporae SW-11^T, Pseudomaricurvus alkylphenolicus KU14G^T, Pseudomaricurvus alcaniphilus MEBiC06469^T and Aestuariicella hydrocarbonica SM-6^T. The major polar lipids of strain R142^T were phosphatidylethanolamine and phosphatidylglycerol. The primary cellular fatty acids were C_{16 : 0}, C_{16 : 1}ω7c, C_{18 : 1}ω7c, C_{18 : 0} and C_{14 : 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 R142^T from all validly published type strains. Strain R142^T 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 R142^T (=MCCC 1K03816^T=KCTC 72138^T).

Keywords: Exilibacterium tricleocarpae; phylogenetics; phylogenomics.