Aestuariibius violaceus sp. nov., isolated from a marine limpet Cellana toreuma

Abstract

A novel bacterium, designated strain 2305UL40-4^T, was isolated from Cellana toreuma (a Korean limpet) collected from Ulleung Island, Republic of Korea. The cells were Gram-stain-negative, aerobic, rod-shaped (0.5-0.9 µm×1.5-2.2 µm) and non-motile. Growth was observed at 22-36 °C (optimum 25-30 °C), pH 6-8 (optimum pH 7) and in the presence of 0.5-4.0% (w/v, optimum 2.0%) NaCl. The 16S rRNA gene sequence analysis revealed that strain 2305UL40-4^T shared 97.4% similarity with Aestuariibius insulae DBTF-13^T. The average nucleotide identity value between the two strains was 76.5%, and the digital DNA-DNA hybridization value was 19.0%. Both values are well below the species delineation thresholds. The DNA G+C content of strain 2305UL40-4^T was 63.8 mol%. The major fatty acids were C_{16 : 0}, C_{18 : 0} and summed feature 8 (C_{18 : 1} ω7c and/or C_{18 : 1} ω6c). Major polar lipids included phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, five unidentified aminolipids and fifteen unidentified lipids. Ubiquinone-10 was the predominant quinone. The new strain differs from A. insulae in its ability to utilize d-raffinose, d-ribose and d-xylose. Based on these polyphasic taxonomic characteristics, strain 2305UL40-4^T is proposed as a novel species within the genus Aestuariibius, with the name Aestuariibius violaceus sp. nov. The type strain is 2305UL40-4^T (=KCCM 43505^T=MCCC 1K09164^T).

Keywords: Cellana toreuma; Ulleung Island; genus Aestuariibius; genus Aestuariibius metabolism.

Fig. 1.. Phylogenomic tree constructed using IQ-TREE. The numbers at each node represent aLRT values obtained through bootstrap analysis with 1,000 replicates.

Fig. 2.. KEGG Orthology-based analysis.

Fig. 3.. Sox system pathways and the corresponding enzyme EC numbers in strain 2305UL40-4ᵀ.