Taxonomic Analysis Of Four Novel Deep-sea Bacteria Species(Luteimonas Abyssi Sp.nov. Etc.) Isolated From Sediment Of South Pacific Gyre

The South Pacific Gyre (SPG,20°-45°S) is the biggest gyre in the world which isleast affected by human activities because the SPG center is far away from thecontinent. It is an oligotrophic area with low sedimentation rate, low primaryproductivity and low microorganisms abudance. There was almostly no study aboutthe microbial community in the SPG before IODP329, so it is easier to find novelbacteria in this new area. Taxonomic analysis of novel bacteria still plays an importantrole in the study of marine microbiology as a prerequisite for the development ofmarine microbial resources. They can enrich the diversity of marine microorganisms,help to research new function genes and their roles in biogeochemical cycles. Sixnovel marine bacteria isolated from sediment of SPG during IODP329were studiedusing ployphasic approach. They were designated XH031T, XH038-3, XH80-1,XH089T, XH274Tand XH208Trespectively.Cells of XH031T, XH038-3and XH80-1were Gram-stain-negative, strictlyaerobic, motile rods (0.2–0.4μm in width,1.0–1.6μm in length) with single polarflagellum. Oxidase and catalase were positive. DNA, starch, gelatin, casein, andTweens20,40and80were hydrolyzed. The dominant fatty acids were iso-C15:0,iso-C16:0and iso-C11:0. The major respiratory quinone was Q-8. The major polar lipidswere phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, andone unknown phospholipid. The DNA G+C contents were70.2-73.9mol%. The16SrRNA gene sequences of XH038-3and XH80-1were almost identical to XH031T,with99.64%and99.66%similarity respectively. The16S rRNA gene sequence ofXH031Twas most closely related to Luteimonas aestuarii B9Twith96.95%sequencesimilarity. On the basis of data from the polyphasic analysis, XH031T, XH038-3and XH80-1were considered to represent members of a novel species in the genusLuteimonas, for which the name Luteimonas abyssi sp. nov. is proposed. The typestrain is XH031T(=DSM25880T=CGMCC1.12611T).Cells of XH089Twere Gram-stain-negative, facultatively anaerobic, motile rods(0.8–1.2μm in length,0.2–0.3μm in width) with single sub-polar or lateral flagellumwhich occur as single units or in pairs. Oxidase and catalase were positive. Tween20and Tween40were degraded. Gelatin, DNA, starch, casein, agar and Tween80werenot hydrolyzed. The dominant fatty acids were C16:0and C17:0cyclo. The major polarlipids were phosphatidylethanolamine, phosphatidylmonomethylethanolamine,diphosphatidylglycerol, three unknown phospholipids, and four unknown polar lipids.The major respiratory quinone was Q-8. The DNA G+C content was66.5mol%. The16S rRNA gene sequence of XH089Twas most closely related to Achromobacterruhlandii ATCC15749Twith96.95%sequence similarity. On the basis of data fromthe polyphasic analysis, strain XH089Twas considered to represent a novel species ofa novel genus in the family Alcaligenaceae, for which the name Oceanobacteriumsediminum gen. nov., sp. nov. is proposed. The type strain is XH089T(=DSM27279T=JCM19223T).Cells of XH274Twere Gram-stain-positive, strictly aerobic, non-motile rods(1.2–1.4μm in length,0.4–0.5μm) without any flagella. Oxidase was negative andcatalase was positive. DNA, gelatin, casein, Tweens20,40and80were degraded.Agar and starch were not hydrolyzed. The dominant fatty acids were iso-C16:0, C18:1ω9c and C17:1ω8c. The major respiratory quinone was menaquinone MK-8(H4). Themajor polar lipids were phosphatidylglycerol, diphosphatidylglycerol,phosphatidylethanolamine and two unknown phospholipids. LL-diaminopimelic acidwas the diagnostic diamino acid of the cell wall. Ribose, glucose, galactose andmannose were the major whole-cell sugars. The DNA G+C content was74.6mol%.The16S rRNA gene sequence of XH274Twas most closely related to Nocardioideskribbensis KSL-2Twith96.81%sequence similarity. On the basis of data from thepolyphasic analysis, strain XH274Twas considered to represent a novel species in thegenus Nocardioides, for which the name Nocardioides pacificus sp. nov. is proposed. The type strain is XH274T(=DSM27278T=JCM19260T).Cells of XH208Twere Gram-stain-positive, strictly aerobic, non-motile cocci(0.2–0.4μm in diameter) and occured singly, in pairs, or in packets without flagellum.Oxidase was negative and catalase was positive. DNA and starch were degraded.Gelatin, casein, agar and Tweens20,40and80were not hydrolyzed. The dominantfatty acids of strain XH208Twere C17:1ω8c, C17:1ω6c and C16:1ω6c and/or C16:1ω7c.The major respiratory quinone was menaquinone MK-9(H4). The major polar lipidswere phosphatidylglycerol, diphosphatidylglycerol and phosphatidylinositol. Ribose,glucose, galactose and trace amounts of mannose were the major whole-cell sugars.The DNA G+C content was66.9mol%. The16S rRNA gene sequence of XH208Twas most closely related to Luteococcus peritonei CCUG38120Twith96.9%sequence similarity. On the basis of data from the polyphasic analysis, strain XH208Twas considered to represent a novel species in the genus Luteococcus, for which thename Luteococcus sediminum sp. nov. is proposed. The type strain is XH208T(=DSM27277T=JCM19259T).Four new species of marine bacteria were identified in this study, and they wereLuteimonas abyssi sp. nov., Oceanobacterium sediminum gen. nov., sp. nov.,Nocardioides pacificus sp. nov. and Luteococcus sediminum sp. nov. respectively.They enriched the diversity of deep-sea microorganisms and laid the foundation forthe research of the function and mechanism of deep-sea microorganisms inbiogeochemical cycles.