Shewanella oncorhynchi sp. nov., a novel member of the genus Shewanella, isolated from Rainbow Trout (Oncorhynchus mykiss)
Soner Altun, Muhammed Duman, Hilal Ay, İzzet Burçin Satıcıoğlu
Abstract
A strain, S-1 T was isolated from rainbow trout ( Oncorhynchus mykiss ) exhibiting clinical symptoms of lens atrophy, inappetence, visual impairment and growth retardation. The strain was identified as representing a member of the genus Shewanella on the basis of the results of 16S rRNA gene sequence analysis. The neighbor-joining phylogenetic tree based on 16S rRNA gene sequences indicated that S-1 T clustered with Shewanella putrefaciens JCM 20190 T , Shewanella profunda DSM 15900 T , and Shewanella hafniensis P010 T , sharing 99.3, 98.8 and 87.7% 16S rRNA gene similarities, respectively. A polyphasic taxonomic approach including phenotypic, chemotaxonomic, and genomic characterization was employed to ascertain the taxonomic position of S-1 T within the genus Shewanella . The overall genome relatedness indices (OGRI) for S-1 T compared with the most closely related type strains S. hafniensis ATCC BAA-1207 T , Shewanella baltica NCTC 10735 T , S. putrefaciens ATCC 8071 T and S. profunda DSM 15900 T were calculated as 40.8, 40.1, 28.5 and 27.3% for digital DNA–DNA hybridization (dDDH), and 91.6, 91.0, 86.3 and 85.1% for average nucleotide identity (ANI), respectively. OGRI values between S-1 T and its close neighbours confirmed that the strain represents a novel species in the genus Shewanella .The DNA G+C content of the strain is 45.2%. Major fatty acids were C 17 : 1 ω8 c , C 15 : 0 iso, and summed feature 3 (C 16 : 1 ω6 c and/or C 16 : 1 ω7 c ). The predominant polar lipids were phosphatidylethanolamine, phospholipid, amino-phospholipid and unidentified lipids. The major respiratory quinones were ubiquinone-8, ubiquinone-7 and menaquinone-7. Chemotaxonomic and phylogenomic analyses of this isolate confirmed that the strain represents a novel species for which the name Shewanella oncorhynchi sp. nov. is proposed, with S-1 T as the type strain (JCM 34183 T = KCTC 82249 T ).