Roseivivax isoporae sp. nov., isolated from a reef-building coral, and emended description of the genus Roseivivax

Abstract

A bacterial strain, isolated from a sample of reef-building coral (Isopora palifera) collected off the coast of southern Taiwan, was characterized using a polyphasic taxonomic approach. The strain, designated sw-2T, was Gram-staining-negative, aerobic, rod-shaped and motile, with subpolar flagella, and formed greyish pink colonies. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain sw-2T was most closely related to Roseivivax halodurans Och 239T (97.4 % sequence similarity) and Roseivivax halotolerans Och 210T (96.4 %). The novel strain did not require NaCl for growth and exhibited optimal growth at 35–40 °C, at pH 7.5–8.0 and with 3–7 % (w/v) NaCl. It produced bacteriochlorophyll a under aerobic conditions. Summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c; 63.7 %) predominated in the cellular fatty acid profile. The novel strain’s major respiratory quinone was ubiquinone Q-10 and its genomic DNA G+C content was 68.8 mol%. The polar lipid profile consisted of a mixture of phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, diphosphatidylglycerol, phosphatidyldimethylethanolamine, sulfo-quinovosyl diacylglycerol and three uncharacterized phospholipids. The level of DNA–DNA relatedness between strain sw-2T and Roseivivax halodurans Och 239T was only 15.0 %. The results of physiological and biochemical tests allowed the clear phenotypic differentiation of the novel strain from all established species of the genus Roseivivax . Based on the genotypic, phenotypic and chemotaxonomic data, strain sw-2T represents a novel species in the genus Roseivivax , for which the name Roseivivax isoporae sp. nov. is proposed. The type strain is sw-2T ( = LMG 25204T = BCRC 17966T).