Comparative 16S rRNA signatures and multilocus sequence analysis for the genus Salinicola and description of Salinicola acroporae sp. nov., isolated from coral Acropora digitifera.

Abstract

A novel Gram-negative, aerobic, motile marine bacterium, strain S4-41(T), was isolated from mucus of the coral Acropora digitifera from the Andaman Sea. Heterotrophic growth was observed in 0-25 % NaCl, at 15-45 °C and pH 4.5-9. In phylogenetic trees, strain S4-41(T) was grouped within the genus Salinicola but formed a separate branch distant from a cluster composed of Salinicola salarius M27(T) and Salinicola socius SMB35(T). DNA-DNA relatedness between strain S4-41(T) and these reference strains were well below 70 %. Q-9 was the sole respiratory quinone. The DNA G+C content was determined to be 63.6 mol%. Based on a polyphasic analysis, strain S4-41(T) is concluded to represent a novel species in the genus Salinicola for which the name Salinicola acroporae sp. nov. is proposed. The type strain is S4-41(T) (=JCM 30412(T) = LMG 28587(T)). Comparative 16S rRNA analysis of the genera Salinicola, Kushneria, Chromohalobacter and Cobetia revealed the presence of genus specific sequence signatures. Multilocus sequence analysis based on concatenated sequences of rRNAs (16S and 23S) and four protein coding housekeeping genes (atpA, gyrB, secA, rpoD) was found to be unnecessary for phylogenetic studies of the genus Salinicola.