Algicoccus marinus gen. nov. sp. nov., a marine bacterium isolated from the surface of brown seaweed Laminaria japonica

A Gram-staining-negative, strictly aerobic, non-motile, ovoid- to rod-shaped bacterium, designated as HZ20ᵀ, was isolated from the surface of a brown seaweed (Laminaria japonica) sample collected from the East China Sea. Colonies are 1.0–2.0 mm in diameter, smooth, circular, convex and yellow after grown on MA at 28 °C for 72 h. The strain was found to grow at 4–50 °C (optimum, 37 °C), pH 5.0–9.5 (optimum, pH 7.0–7.5) and with 0–10% (w/v) NaCl (optimum, 1.0–1.5%). Chemotaxonomic analysis showed ubiquinone-8 as the only quinone, C₁₇:₀ cyclo, C₁₆:₀, summed feature 8 (C₁₈:₁ω7c and/or C₁₈:₁ω6c) and summed feature 2 (C₁₂:₀ aldehyde/unknown 10.9525/C₁₆:₁ iso I/C₁₄:₀ 3OH) as the major fatty acids (> 5%), and diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, one unidentified amino phospholipid, two unidentified phospholipids, five unidentified glycolipid and two unidentified lipids as the polar lipids. The DNA G + C content was 55.5 mol %. 16S rRNA gene sequences of the isolate showed highest similarities to Bordetella flabilis AU10664ᵀ (97.1%), Parapusillimonas granuli Ch07ᵀ (97.1%), Paracandidimonas soli IMT-305ᵀ (97.1%), Kerstersia gyiorum LMG5906ᵀ (97.0%) and Bordetella sputigena LMG 28641ᵀ (97.0%). The phylogenetic trees using 16S rRNA gene and genome sequences both showed that the strain HZ20ᵀ formed a deep branch separated from other related genera, indicating that it represents a novel species of a novel genus. The calculated average nucleotide identity (ANI) and percent of conserved proteins (POCP) values using genome sequences of strain HZ20ᵀ and related strains also support this conclusion. Based on the phenotypic properties and phylogenetic distinctiveness, we propose strain HZ20ᵀ (= MCCC 1K03465ᵀ = KCTC 62330ᵀ) to represent a novel species of a novel genus with the name Algicoccus marinus gen. nov. sp. nov.