A novel Gram-stain negative, rod-shaped and motile bacterial strain, designated strain Seoho-38T, was isolated from a eutrophic lake in South Korea. Polyphasic taxonomic studies were performed to investigate the taxonomic position of the new isolate. The phylogenetic analysis based on the 16S rRNA gene sequences revealed that strain Seoho-38T formed a distinct cluster with Nevskia ramosa Soe1T, Nevskia persephonica G6M-30T, Nevskia soli GR15-1T, Nevskia terrae KIS13-15T and Nevskia aquatilis F2-63T with bootstrap resampling value of 100%. Of those Nevskia strains, the new isolate shows high sequence similarity with N. ramosa Soe1T (98.7%) and N. persephonica G6M-30T (97.2%), and values lower than 96.5% with the other type strains. The new isolate was observed to grow aerobically in 0-1.5% (w/v) NaCl (optimum 0%), at pH 7.0-9.0 (optimum pH 7.0) and temperature 15-36 °C (optimum 20-30 °C) on R2A medium. DNA-DNA relatedness values between strain Seoho-38T and the type strains of reference species in the genus Nevskia were < 24%. The genomic DNA G + C content was determined to be 67.4 mol%. Ubiquinone-8 (Q-8) (95%) and ubiquinone-7 (Q-7) (5%) were identified as the respiratory quinones. The cellular polar lipids were identified as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, a phosphoaminolipid, two glycolipids, an aminolipid and four unidentified lipids. The major fatty acid components were found to include summed feature 3 (C16:1ω7c and/or C16:1ω6c), summed feature 8 (C18:0ω7c and/or C18:0ω6c), C16:0 and C14:0. Based on the above polyphasic evidence, strain Seoho-38T (= KCTC 52221T = JCM 31888T) represents a new species of the genus Nevskia, for which the name Nevskia lacus sp. nov. is proposed.
Keywords: Harmful cyanobacterial blooms; Nevskia; Nevskia lacus sp. nov.; Polyphasic taxonomy.