A Gram-stain-negative, strictly aerobic, non-motile, rod-shaped, manganese-oxidizing bacterial strain, designated T , was isolated from the surface sediment of the Pacific ClarionClipperton Fracture Zone. Phylogenetic analysis, based on 16S rRNA gene sequences, indicated that strain DY6-4 T formed a lineage within the family Rhodobacteraceae and was distinct from the most closely related genera Sulfitobacter, .9 % 16S rRNA gene sequence similarity, repectively). Optimal growth occurred in the presence of 1 % (w/v) NaCl, at pH 7.0 and at 28 8C. Strain DY6-4 T contained ubiquinone-10 (Q-10) as the major ubiquinone, phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine and one unidentified aminolipid as the predominant polar lipids, C 18 : 1 v7c and summed feature 3 (C 16 : 1 v7c and/or C 16 : 1 v6c) as the main fatty acids (.10 % of the total). The DNA G+C content of strain DY6-4 T was 66.6 mol%.On the basis of the polyphasic analyses, strain DY6-4 T is considered to represent a novel species of a novel genus in the Roseobacter clade of the family Rhodobacteraceae, for which the name Xuhuaishuia manganoxidans gen. nov., sp. nov. is proposed. The type strain is DY6-4 T (5KCTC 42421Since the first description of Roseobacter spp. by Shiba (1991), more than 82 affiliated and genera with validly published names have been described. Members of the Roseobacter clade form a subgroup of the family Rhodobacteraceae that shares 89 % 16S rRNA gene sequence similarity (Buchan et al., 2005). From coastal regions to deep-sea sediments and from polar ice to tropical latitudes, bacteria of this clade have been isolated in a large variety of habitats (Brinkhoff et al., 2008). Most of the cultured members have large genomes, a high DNA G+C content and versatile metabolic capabilities (Luo & Moran, 2014). Use of a multitude of organic compounds, sulfur oxidation, aerobic anoxygenic photosynthesis, the oxidation of a diverse range of metals, DMSP demethylation and the production of secondary metabolites are some of the important traits found in this clade (Imhoff, 2006; Sass et al., 2010;Curson et al., 2011;Lenk et al., 2012). Here we report a novel manganese-oxidizing strain, designated DY6-4 T , within the Roseobacter clade. We investigated its taxonomy using a polyphasic approach. Genomic DNA extraction, PCR amplification, cloning and sequencing of the 16S rRNA gene were performed according to Yu et al. (2013). The almost complete 16S rRNA gene sequence (1384 nt) was submitted to the GenBank database. Pairwise similarity values between strain DY6-4 T and closely related type strains were calculated using the EzTaxon-e server (http://eztaxon-e.ezbiocloud.net/; Kim et al., 2012). 16S rRNA gene sequences of related 3These authors contributed equally to this work.Abbreviations: ECL, equivalent chain length; NJ, neighbour joining; ML, maximum likelihood; MP, maximum parsimony.The GenBank GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of T is KF356416. Phylogenetic trees based on the neighbour-joining ...