Taxonomic Analysis And Related Properties Of Spongiibacterium Pacificum Sp. Nov. And Other Five Novel Bacteria From The South Pacific Gyre

The environment of marine contains some extreme environments such as low-temperature, high-salt and oligotrophic environment which are absent in the terrestrial ecosystem. This extreme environment of ocean will lead to a high diversity of microorganism.The South Pacific Gyre which is far away from the continent becomes the ideal region for exploring the origin and evolution of species because of its less human influence, more natural sedimentation and low nutrition composition. The information of microbial species is very scarce before the Intergrated Ocean Drilling Program （IODP） was launched. Taxonomic analysis of novel bacteria plays an important role in the study of marine microbiology, not only can improve the diversity of species but also provide more new metabolic product for human. The phenotypic and genotypic characteristics of six novel marine bacteria isolated from surface water of SPG during IODP 329 were studied using ployphasic approach. According to the result of the identification, we classified and named these bacteria, and confirmed the taxonomic status of them.SW169^T are Gram-stain-negative, strictly aerobic, non-flagellated, non-gliding and rod-shaped yellow-pigmented bacteria isolated from surface seawater of the South Pacific Gyre. Oxidase is positive but catalase is negative. DNA, starch and aesculin can be degraded. Gelatin, casein, Tweens 20,40 and 80 are not hydrolyzed. The dominant fatty acids are iso-C_15:1 G, iso-C_15:0, iso-C_17:0 3-OH, iso-C_15:0 3-OH and C_16:1 ω6c and/or C_16:1 ω7c. The major respiratory quinone is menaquinone-6 （MK-6）. The major polar lipids are phosphatidylethanolamine, one unidentified aminolipid and one unidentified lipid. The DNA G+C content is 43.3 mol%.The 16S rRNA gene sequence of SW169^T is most closely related to Spongiibacterium flavum AllT with 95.9% sequence similarity. On the basis of data from the polyphasic analysis, SW1691 is considered to represent a novel species in the genus Spongiibacterium, for which the name Spongiibacterium pacificum sp. nov. is proposed. The type strain is SW169^T（=LMG 26997^T=JCM 18379^T）.SW033^T and SW095 are Gram-stain-negative, strictly aerobic, non-flagellated, non-gliding and rod-shaped yellow-pigmented bacteria isolated from surface seawater of the South Pacific Gyre. Oxidase and catalase are positive. DNA, gelatin, starch, casein, and Tweens 20,40 and 80 are hydrolyzed. The dominant fatty acids are iso-C_15:1 G, iso-C_15:0,iso-C_17:0 3-OH, iso-C_15:0 3-OH and C_16:1 ω6c and/or C_16:1 ω7c. The major respiratory quinone is MK-6. The major polar lipids are phosphatidylethanolamine, two unidentified aminolipids and four unidentified lipids. The DNA G+C contents are 35.7 and 36.1 mol% respectively.The 16S rRNA gene sequence of SW095 is almost identical to SW033^Twith 99.45%. The 16S rRNA gene sequence of SW033^T is most closely related to Hyunsoonleella jejuensis CNU004^T with 96.8% sequence similarity. On the basis of data from the polyphasic analysis, SW033^T and SW095 are considered to represent members of a novel species in the genus Hyunsoonleella, for which the name Hyunsoonleella pacifica sp. nov. is proposed. The type strain is SW033^T （= CGMCC 1.11009^T= JCM 17860^T）.SW027^T are Gram-stain-negative, strictly aerobic, non-flagellated, non-gliding and rod-shaped orange-pigmented bacteria isolated from surface seawater of the South Pacific Gyre. Oxidase and catalase are positive. DNA, cellulose, starch and casein not be degraded. Gelatin, aesculin, Tweens 20,40 and 80 are hydrolyzed. The dominant fatty acids are iso-C_15:0, iso-C_15:1 G and iso-C_17:0 3-OH. The major respiratory quinone is MK-6. The major polar lipids are phosphatidylethanolamine and two unidentified lipids. The DNA G+C content is 42.7 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SW027^T shared the highest sequence similarity with members of the genus Muricauda （94.3-92.7%）. On the basis of data from the polyphasic analysis, SW027^T is considered to represent a novel species in the genus Muricauda, for which the name Muricauda pacifica sp. nov. is proposed. The type strain is SW0277 （= JCM 17861^T= LMG 26637^T）.SW230^T are Gram-stain-negative, strictly aerobic, non-flagellated, non-gliding and rod-shaped yellow-pigmented bacteria isolated from surface seawater of the South Pacific Gyre. Oxidase and catalase are positive. Gelatin can not be degraded. DNA, starch, casein, aesculin, Tweens 20,40 and 80 are hydrolyzed. The dominant fatty acids are iso-C_15:0, iso-C_15:1 G, iso-C_17:0 3-OH and C16L:1ω7c and/or C_16:1ω6c. The major respiratory quinone is MK-6. The major polar lipids are phosphatidylethanolamine, two unidentified aminolipids and two unidentified lipids. The DNA G+C content is 35.7 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SW230^T shared the highest sequence similarity with members of the genus Dokdonia （94.5-95.0%）. On the basis of data from the polyphasic analysis, SW230^T is considered to represent a novel species in the genus Dokdonia, for which the name Dokdonia pacifica sp. nov. is proposed. The type strain is SW230^T （= CGMCC 1.12184^T=JCM 18216^T）.XH122^T are Gram-stain-negative, strictly aerobic, non-flagellated, non-gliding and rod-shaped white-pigmented bacteria isolated from surface seawater of the South Pacific Gyre. Oxidase and catalase are positive. Casein and Tweens 20,40 and 80 can be degraded. DNA, gelatin and starch are not hydrolyzed. The dominant fatty acids are C_16:0, C_16:1 ω9c and C_18:1 ω9c. The major respiratory quinone is ubiquinone-8 （Q-8）. The major polar lipids are phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The DNA G+C content is 46.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain XH122^T belonged to the genus Leucothrix and showed the highest 16S rRNA gene sequence similarity with Leucothrix mucor DSM 2157^T （94.3%）. On the basis of data from the polyphasic analysis, XH122^T is considered to represent a novel species in the genus Leucothrix, for which the name Leucothrix pacifica sp. nov. is proposed. The type strain is XH122^T （= DSM 25984^T= JCM 18388^T）.Five new species of marine bacteria are identified in this study, and they are Spongiibacterium pacificum sp. nov., Hyunsoonleella pacifica sp. nov., Muricauda pacifica sp. nov., Dokdonia pacifica sp. nov. and Leucothrix pacifica sp. nov. respectively. The results in this study enriched the diversity of species and lay a foundation for researching the biogeochemical cycles.