Qipengyuania benthica sp. nov. and Qipengyuania profundimaris sp. nov., two novel Erythrobacteraceae members isolated from deep-sea environments

Abstract

Two Gram-stain-negative, rod-shaped and non-motile strains, designated as DY56-A-20^T and G39^T, were isolated from deep-sea sediment of the Pacific Ocean and deep-sea seawater of the Indian Ocean, respectively. Strain DY56-A-20^T was found to grow at 15-37 °C (optimum, 28 °C), at pH 6.0-10.0 (optimum, pH 6.5-7.0) and in 0.5-6.0 % (w/v) NaCl (optimum, 1.0-2.0 %), while strain G39^T was found to grow at 10-42 °C (optimum, 35-40 °C), at pH 5.5-10.0 (optimum, pH 6.5-7.0) and in 0-12.0 % (w/v) NaCl (optimum, 1.0-2.0 %). The 16S rRNA gene sequence identity analysis indicated that strain DY56-A-20^T had the highest sequence identity with Qipengyuania marisflavi KEM-5^T (97.6 %), while strain G39^T displayed the highest sequence identity with Qipengyuania citrea H150^T (98.8 %). The phylogenomic reconstruction indicated that both strains formed independent clades within the genus Qipengyuania. The digital DNA-DNA hybridization and average nucleotide identity values between strains DY56-A-20^T/G39^T and Qipengyuania/Erythrobacter type strains were 17.8-23.8 % and 70.7-81.1 %, respectively, which are below species delineation thresholds. The genome DNA G+C contents were 65.0 and 63.5 mol% for strains DY56-A-20^T and G39^T, respectively. The predominant cellular fatty acids (>10 %) of strain DY56-A-20^T were C_{17 : 1} ω6c, summed feature 8 and summed feature 3, and the major cellular fatty acids of strain G39^T were C_{17 : 1} ω6c and summed feature 8. The major polar lipids in both strains were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, sphingoglycolipid and an unidentified polar lipid. The only respiratory quinone present in both strains was ubiquinone-10. Based on those genotypic and phenotypic results, the two strains represent two novel species belonging to the genus Qipengyuania, for which the names Qipengyuania benthica sp. nov. and Qipengyuania profundimaris sp. nov. are proposed. The type strain of Q. benthica is DY56-A-20^T (=MCCC M27941^T=KCTC 92309^T), and the type strain of Q. profundimaris is G39^T (=MCCC M30353^T=KCTC 8208^T).

Keywords: Qipengyuania benthica; Qipengyuania profundimaris; deep-sea environment; polyphasic taxonomy.