Rheinheimera tilapiae sp. nov., isolated from a freshwater culture pond.

A bacterial strain designated Ruye-90(T) was isolated from a freshwater tilapiine cichlid fish culture pond in Taiwan and characterized using a polyphasic taxonomic approach. Strain Ruye-90(T) was gram-negative, aerobic, yellow-coloured, rod-shaped, and motile by means of a single polar flagellum. Growth occurred at 4-30 °C (optimum, 20-30 °C), at pH 7.0-9.0 (optimum, pH 8.0-9.0) and with 0-2 % NaCl (optimum, 0 %). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain Ruye-90(T) belonged to the genus Rheinheimera and its most closely related neighbour was Rheinheimera tangshanensis JA3-B52(T) with sequence similarity of 97.5 %. The major fatty acids were summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c, 41.3 %), C16 : 0 (19.3 %), C18 : 1ω7c (8.4 %) and C12 : 0 3-OH (7.0 %). The major respiratory quinone was Q-8. The DNA G+C content of the genomic DNA was 49.0 mol%. The polar lipid profile consisted of a mixture of phosphatidylethanolamine, phosphatidylglycerol, phosphatidylserine, aminolipid and two uncharacterized phospholipids. The DNA-DNA relatedness of strain Ruye-90(T) with respect to recognized members of the genus Rheinheimera was less than 70 %. On the basis of the genotypic, chemotaxonomic and phenotypic data, strain Ruye-90(T) represents a novel species in the genus Rheinheimera, for which the name Rheinheimera tilapiae sp. nov. is proposed. The type strain is Ruye-90(T) ( = LMG 26339(T) = BCRC 80263(T) = KCTC 23315(T)).