Aequorivita lutea sp. nov., a novel bacterium isolated from the estuarine sediment of the Pearl River in China, and transfer of Vitellibacter todarodis and Vitellibacter aquimaris to the genus Aequorivita as Aequorivita todarodis comb. nov. and Aequorivita aquimaris comb. nov.

Abstract

A Gram-negative, aerobic, rod-shaped, non-motile by gliding bacterium was isolated from the estuarine sediment of the Pearl River in PR China and designated as strain q18^T. Colonies were circular, smooth and yellow on marine agar after 48 h cultivation. Salinity, temperature and pH for optimal growth were 5 % (NaCl), 30 °C and 7, respectively. The 16S rRNA gene sequence of the strain q18^T showed the highest similarity of 97.3 % to the type strain of <i>Aequorivita echinoideorum</i> CC-CZW007^T. 16S rRNA gene-based phylogenetic analysis indicated that strain q18^T grouped into the genus <i>Aequorivita</i> in the family <i>Flavobacteriaceae</i> of the phylum <i>Bacteroidetes</i>, and was distinct from all known species in the genus. Menaquinone (MK-6) was the main respiratory quinone detected in strain q18^T. The major fatty acids were iso-C_{15 : 0} and iso-C_{17 : 0} 3-OH. The polar lipids of strain q18^T mainly comprised phosphatidylethanolamine, two unidentified aminolipids, two unidentified phospholipids and one unidentified polar lipid. The G+C content of the genome was ~42.8 mol%. The draft genome size of strain q18^T was 3.3 Mbp. The average nucleotide identity values were around 79.0 % between strain q18^T and reference <i>Aequorivita</i> strains. Based on the polyphasic analysis, strain q18^T was confirmed to represent a novel species of the genus <i>Aequorivita</i>, for which the name <i>Aequorivita lutea</i> sp. nov., is proposed. The type strain is q18^T (=CICC 24821^T=KCTC 72764 ^T). Further, based on the results of phylogenetic, chemotaxonomic and phenotypic analyses, two species previously classified into the genus <i>Vitellibacter</i>, <i>Vitellibacter todarodis</i> Kim <i>et al</i>. 2018 and <i>Vitellibacter aquimaris</i> Thevarajoo <i>et al</i>. 2016, are transferred to the genus <i>Aequorivita</i> as <i>Aequorivita todarodis</i> comb. nov. and <i>Aequorivita aquimaris</i> comb. nov. respectively.