Roseovarius conchicola sp. nov. and Aliiroseovarius conchicola sp. nov., isolated from the marine conch Reishia bronni

The intertidal zone is an area located between the marine environment and the terrestrial environment and is exposed to various stresses. To investigate the mutualistic relationship between hosts and symbiotic micro-organisms inhabiting the intertidal zone, strains 2305UL8-3T and 2305UL8-7T were isolated from Reishia bronni, a species living in the intertidal zone of Ulleungdo Island, South Korea. Both strains are Gram-stain-negative, catalase- and oxidase-positive and facultatively anaerobic. Strains 2305UL8-3T and 2305UL8-7T grow optimally at 30.0 °C and 28.0-30.0 °C, respectively, under conditions of pH 8.0 and 3.0 % (w/v) NaCl. They have Q-10 as the primary quinone, and their common main fatty acids are C16:0 and summed feature 8 (C18:1 ω7c and/or C18:1 ω6c). Additionally, their primary polar lipids include phosphatidylcholine and phosphatidylglycerol. The two novel strains have an arsenic reduction pathway that reduces the oxidation state of arsenic and are expected to influence environmental regulation processes through the catabolic sulphate reduction system. Based on these characteristics, they exhibit resistance potential to environmental stresses, specifically arsenic exposure in the intertidal zone, where arsenic contamination is often associated with pollution and tidal fluctuations. Analysing the 16S rRNA gene sequence similarity, strain 2305UL8-3T shared 96.60 % similarity with Roseovarius faecimaris MME-070T, while strain 2305UL8-7T showed 98.13 % similarity with Aliiroseovarius sediminilitoris M-M10T. Polyphasic analysis revealed that strains 2305UL8-3T and 2305UL8-7T should be identified as novel species within the genera Roseovarius and Aliiroseovarius, respectively. Therefore, Roseovarius conchicola sp. nov. with the type strain 2305UL8-3T (=KCTC 8475T=MCCC 1K09523T=JCM 37202T) and Aliiroseovarius conchicola sp. nov. with the type strain 2305UL8-7T (=KCTC 8476T=MCCC 1K09524T=JCM 37203T) are proposed.

Roseovarius pelagicus sp. nov., a facultatively anaerobic bacterium with potential for degrading polypropylene, isolated from Arctic seawater

A Gram-stain-negative, facultatively anaerobic, non-motile, rod-shaped bacterial strain, designated HL-MP18T, was isolated from Arctic seawater after a prolonged incubation employing polypropylene as the sole carbon source. Phylogenetic analyses of the 16S rRNA gene sequence revealed that strain HL-MP18T was affiliated to the genus Roseovarius with close relatives Roseovarius carneus LXJ103T (96.8 %) and Roseovarius litorisediminis KCTC 32327T (96.5 %). The complete genome sequence of strain HL-MP18T comprised a circular chromosome of 3.86 Mbp and two circular plasmids of 0.17 and 0.24 Mbp. Genomic comparisons based on average nucleotide identity and digital DNA-DNA hybridization showed that strain HL-MP18T was consistently discriminated from its closely related taxa in the genus Roseovarius. Strain HL-MP18T showed optimal growth at 25 °C, pH 7.0 and 2.5 % (w/v) sea salts. The major cellular fatty acids were C18 : 1  ω6c and/or C18 : 1  ω7c (49.6 %), C19 : 0 cyclo ω8c (13.5 %), and C16 : 0 (12.8 %). The major respiratory quinone was ubiquinone-10. The polar lipids consisted of phosphatidylcholine, phosphatidylglycerol, an unidentified aminolipid and three unidentified lipids. The genomic DNA G+C content of the strain was 59.2 mol%. The phylogenetic, genomic, phenotypic and chemotaxonomic results indicate that strain HL-MP18T is distinguishable from the recognized species of the genus Roseovarius. Therefore, we propose that strain HL-MP18T represents a novel species belonging to the genus Roseovarius, for which the name Roseovarius pelagicus sp. nov. is proposed. The type strain is HL-MP18T (=KCCM 90405T=JCM 35639T).

Roseovarius carneus sp. nov., a novel bacterium isolated from a coastal phytoplankton bloom in Xiamen

A Gram-stain-negative, non-motile, ovoid or short rod shaped and aerobic marine bacterium, designated as strain LXJ103T, was isolated from a coastal phytoplankton bloom in Xiamen, PR China. Cells were oxidase- and catalase-positive. Strain LXJ103T grew at 4–40 °C (optimum, 28–37 °C), at pH 6–10 (optimum, pH 8.5) and with 1–15 % (w/v) NaCl (optimum, 3 %). The major cellular fatty acids (>10 %) were iso-C18 : 1  ω7c/iso-C18 : 1  ω6c (70.2 %) and C16 : 0 (10.3 %). The following polar lipids were found to be present: phosphatidylglycerol, phosphatidylethanolamine, two unidentified phospholipids and five unknown glycolipids. The predominant respiratory quinone was ubiquinone-10. Strain LXJ103T exhibited the highest 16S rRNA gene sequence similarity to Roseovarius litorisediminis D1-W8T (96.97 %). The phylogenetic trees based on 16S rRNA gene sequences showed that strain LXJ103T was a member of the genus Roseovarius . The draft genome size of strain LXJ103T is 3.05 Mb with a genomic G+C content of 61.22 mol%. The digital DNA–DNA genome hybridization value of strain LXJ103T compared with the most similar type strain R. litorisediminis CECT 8287T was 18.80 %. The average nucleotide identity value between strain LXJ103T and R. litorisediminis CECT 8287T was 72.60 %. On the basis of polyphasic data, strain LXJ103T represents a novel species of the genus Roseovarius , for which the name Roseovarius carneus sp. nov. is proposed. The type strain is LXJ103T (=CGMCC 1.19168T=MCCC 1K06527T=JCM 34778T).

Draft Genome Sequence of Roseovarius sp. PS-C2, Isolated from Sekinchan Beach in Selangor, Malaysia

Roseovarius sp. PS-C2 is a bacterium that was isolated from Sekinchan Beach in Selangor, Malaysia, using an ex situ cultivation technique. Here, we present a high-quality annotated draft genome of strain PS-C2 and suggest potential applications of this bacterium.

Pseudopuniceibacterium antarcticum sp. nov., isolated from an Antarctic marine sponge

A Gram-negative, aerobic, rod-shaped, non-motile bacterium, designated strain HQ09^T, was isolated from a marine sponge off the coast of Fields Peninsula, West Antarctica. Strain HQ09^T grew at 4-35 °C (optimum, 25 °C), pH 5-9 (optimum, pH 7.0), and with 1-10% NaCl (optimum, 2 %). Phylogenetic analysis based on the 16S rRNA gene sequences showed that strain HQ09^T was affiliated with the genus Pseudopuniceibacterium in the family Rhodobacteraceae, sharing 99.64 % identity with the type strain of Pseudopuniceibacterium sediminis, the only known species in the genus. However, the low digital DNA-DNA hybridization (dDDH) (27.2 %) and average nucleotide identity (ANI) (83.63 %) values between strain HQ09^T and the type strain of Pseudopuniceibacterium sediminis indicated that they did not belong to the same species. Strain HQ09^T could also be differentiated from Pseudopuniceibacterium sediminis by many phenotypic characteristics. The major fatty acids (>5 %) of strain HQ09^T were summed feature 8 (C_18 : 1  ω7c/C_18 : 1 ω6c), 11-methyl C_18 : 1  ω7c, C_16 : 0 and C19 : 0 cyclo ω8c. The polar lipids included phosphatidylglycerol, phosphatidylcholine, two unidentified aminolipids and one unidentified phospholipid. The predominant respiratory quinone was ubiquinone 10 (Q-10). The genomic DNA G+C content was 62.63 mol%. Four secondary metabolite biosynthetic gene clusters were detected in the genome, potentially producing ectoine and three types of unknown compounds. On the basis of the polyphasic evidences obtained in this study, strain HQ09^T represents a novel species of the genus Pseudopuniceibacterium, for which the name Pseudopuniceibacterium antarcticum sp. nov. is proposed, with the type strain being HQ09^T (=KCTC 52229^T=CGMCC 1.15538^T).