Genomic and phenotypic characterisation of Leeuwenhoekiella obamensis sp. nov., a novel marine bacterium isolated from the surface water of a Japanese fishing port.

Abstract

A novel aerobic marine bacterium, FRT2^T, isolated from surface water of a fishing port in Fukui, Japan, was characterised based on phylogenomic and phylogenetic analyses combined with classical phenotypic and chemotaxonomic characterisations. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain FRT2^T clustered with genus Leeuwenhoekiella. Closest relatives of FRT2^T were Leeuwenhoekiella palythoae KMM 6264^T and Leeuwenhoekiella nanhaiensis G18^T with 16S rRNA gene sequence identities of 95.1% and 94.5%, respectively, suggesting that FRT2^T is a novel species of genus Leeuwenhoekiella. Phylogenetic analysis of 81 bacterial core gene sequences also placed FRT2^T in a highly supported lineage distinct from described Leeuwenhoekiella species. Values of digital DNA-DNA hybridisation and average nucleotide identity between FRT2^T and type strains of species of genus Leeuwenhoekiella indicate that FRT2^T is a novel species of the genus Leeuwenhoekiella. Cells were Gram-stain-negative rods with 0.3-0.8 µm width and 1.6-4.1 µm length. The bacterium was strictly aerobic, produced yellow-orange-pigments and showed gliding motility. Na⁺ was needed to grow FRT2^T with optimal growth in the presence of 3.0-4.0% (w/v) NaCl. Growth pH and temperature ranges were 5.5-8.5 (optimum pH 6.5-7.5) and 10-39 °C (optimum 25-35 °C), respectively. Major cellular fatty acids were iso-C_15:0, iso-C_15:1, iso-C_17:0 3-OH and summed feature 3 (C_16:1ω6c and/or C_16:1ω7c). The only respiratory quinone was MK-6. Genomic G + C content of FRT2^T was 38.9%. FRT2^T represents a novel species, for which the name Leeuwenhoekiella obamensis sp. nov. is proposed, with type strain FRT2^T (= BCRC 81451^T = DSM 118489^T = JCM 36940^T).