Aquimarina rhabdastrellae sp. nov., isolated from the marine sponge Rhabdastrella globostellata

A Gram-stain-negative, aerobic, motile-by-gliding bacterium, designated strain RHTr2^T, was isolated from the marine sponge <i>Rhabdastrella globostellata</i> collected in waters surrounding the Penghu Islands, Taiwan. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain RHTr2^T displayed the highest 16S rRNA gene sequence similarities to <i>Aquimarina versatilis</i> CBA3207^T (94.2%), <i>Aquimarina acroporae</i> D1M17^T (93.7%) and <i>Aquimarina intermedia</i> LMG 23204^T (93.2%). Strain RHTr2^T grew with 1-5% (w/v) NaCl (optimum, 2-3%), at 17-37 °C (optimum, 30 °C) and at pH 6.0-8.0 (optimum, pH 6.0-7.0). Strain RHTr2^T was able to degrade starch, Tweens (20, 40 and 80) and gelatin; flexirubin-type pigments were produced. Strain RHTr2^T contained menaquinone 6 as the major respiratory quinone, and iso-C_{15 : 0} and iso-C_{17 : 0} 3-OH as major fatty acids (> 10%). The polar lipids of strain RHTr2^T were an unidentified aminophospholipid, three aminolipids, a phospholipid and an unidentified polar lipid. The DNA G+C content was 31.4 mol% based on genome sequence analysis. The average nucleotide identity and digital DNA-DNA hybridization values between strain RHTr2^T and the most closely related members of the <i>Aquimarina</i> genus were lower than the recommended thresholds for species delineation. Based on its phenotypic and genotypic characteristics and on the phylogenetic and phylogenomic evidence presented, strain RHTr2^T represents a novel species of the genus <i>Aquimarina</i> for which the name <i>Aquimarina rhabdastrellae</i> sp. nov. is proposed. The type strain is RHTr2^T (=JCM 37598^T=UCCCB 217^T).