Arcobacter iocasae sp. nov., a bacterium isolated from the gill homogenate of the mussel Gigantidas platifrons in a cold seep

A novel Gram-negative, oxidase- and catalase-positive, rod-shaped bacterium, designated strain KX21116^T, was isolated from the mussel <i>Gigantidas platifrons</i> collected from a cold seep field in the South China Sea. Strain KX21116^T grew optimally at 28 °C, pH 6.0 with 3% (w/v) NaCl, under aerobic and microaerobic conditions. Its genome size was 3.16 Mb, with a G+C content of 28.4 mol%. The 16S rRNA sequences revealed that strain KX21116^T was closely related to <i>Arcobacter nitrofigilis</i> DSM 7299^T (98.77% gene sequence similarity) and <i>Arcobacter acticola</i> AR-13^T (95.58%). Phylogenetic and phylogenomic analysis revealed that strain KX21116^T clustered with the type species of the genus <i>Arcobacter</i>, with <i>A. nitrofigilis</i> DSM 7299^T as its nearest neighbour. The genomic average nucleotide identity (orthoANI) values between strain KX21116^T and <i>A. nitrofigilis</i> DSM 7299^T were 92.74%, while the <i>in silico</i> DNA-DNA hybridization (GGDC) values of the two strains were 48.8%. The predominant fatty acids are C_16:0, C_16:1 <i> ω7</i>c/C1_6:1 <i> ω6</i>c and C_18:1 <i> ω7</i>c/C1_8:1 <i> ω6</i>c. Based on a comparative analysis of phylogenetic, phylogenomic, phenotypic and chemotaxonomic characteristics, strain KX21116^T represents a novel species of the genus <i>Arcobacter</i>, for which the name <i>Arcobacter iocasae</i> sp. nov. is proposed. The type strain is KX21116^T (=MCCC 1K08505^T=KCTC 92900^T=JCM 35939^T).