Pseudomonas ovata sp. nov., Isolated from the Skin of the Tail of Farmed Murray cod (Maccullochella peelii peelii) with a Profound Ulceration

Abstract

A Gram-negative, strictly aerobic, motile, rod-shaped bacterium with monopolar flagellum, designated as F51^T, was isolated from the skin ulcer of farmed Murray cod sampled from Zhejiang Province, China. Strain F51^T grew at 4-37 °C (optimal temperature, 28 °C), pH 5.0-8.5 (optimal pH, 7.5) and NaCl concentration of 0-6.0% (w/v) (optimal concentration, 2.0%). Phylogenetic analysis based on average nucleotide identity (76.2-78.4%) and in silico DNA-DNA hybridization (22.3-23.2%) values revealed that strain F51^T forms a distinct lineage in the clade of genus Pseudomonas with less than 98.9% 16S rRNA gene sequence similarity to type strains of the genus and represents a novel species related most closely to Pseudomonas floridensis LMG 30013^T. Three housekeeping genes (rpoB, rpoD and gyrB) of strain F51^T were analysed to further confirm that the isolate is distinctly delineated from related Pseudomonas species. Chemotaxonomic analysis indicated that the sole respiratory quinone of strain F51^T is Q-9; its predominant cellular fatty acids are C_16:0, summed feature 3 (iso-C_15:0 2-OH and/or C_16:1ω7c), summed feature 8 (C_18:1ω7c and/or C_18:1ω6c) and C_10:0 3-OH; and its major polar lipids consist of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, two unidentified glycolipids, three unidentified phospholipids and an unidentified aminophosphoglycolipid. This composition is typical of the chemotaxonomic attributes of Pseudomonas. Based on its phenotypic, chemotaxonomic and phylogenetic features, strain F51^T is considered to represent a novel species for which the name Pseudomonas ovata sp. nov. is proposed. The type strain is F51^T (= KCTC 62133^T = MCCC 1K03458^T).