Polyphasic Taxonomy Of Four Marine Bacteria From The South China Sea And The Arctic

In this study,four bacteria respectively isolated from surface seawater samples of the South China Sea and the Arctic,were taxonomically characterized using a polyphasic taxonomic apporach incuding phenotypic,chemotaxonomic and genotypic characterization,based on which their taxonomic positions were finally determined.1.Polyphasic taxonomic analysis of strain SM1501~TA Gram-reaction-negative,aerobic,non-flagellated,rod-shaped bacterium,designed strain SM1501~T,was isolated from surface seawater of the South China Sea.Strain SM1501~T grew at 7-42? and with 0-11%(w/v)NaCl.The predominant cellular fatty acids of strain SM1501~T were C17:1?6c,C15:0 2-OH,C17:1?8c and C18:1?7c.The major polar lipids of the strain were phosphatidylethanolamine(PE),phosphatidylglycerol(PG),sphingoglycolipid(SGL),diphosphatidylglycerol(DPG)and phosphatidylcholine(PC).The main respiratory quinine of strain SM1501~T was ubiquinone Q-10.The genomic DNA G+C content of strain SM1501~T was 66.8 mol%.Phylogenetic analyses of 16S rRNA gene sequences revealed that strain SM1501~T belonged to the genus Erythrobacter,sharing 94.2-97.44%16S rRNA gene sequence similarities to recognized Erythrobacter species.The phylogenetic trees based on 16S rRNA gene sequences showed that strains SM1501~T clustered with Erythrobacter luteus,Erythrobacter atlanticus,Erythrobacter gangjinensis and Erythrobacter marinus,forming a distinct phylogenetic sub-branch.Polyphasic data presented in this paper support the notion that strain SM1501~T represents a novel species in the genus Erythrobacter,for which the name Erythrobacter nanhaiensis sp.nov.is proposed.The type strain of Erythrobacter nanhaiensis is SM1501~T(= KCTC 42669-T= CCTCC AB 2015396T).2.Polyphasic taxonomic analysis of strain SM1502~TA Gram-reaction-negative,aerobic,non-flagellated and rod-shaped bacterium,designated strain SM1502~T,was isolated from Arctic seawater.The isolate grew at 10-40? and with 0-8.0%(w/v)NaCl.The major fatty acids of strain SM1502~T were iso-C15:0,iso-C17:?9c,iso-C17:0 3-OH,iso-C15:1 G,C15:0 and unknown ECL 13.565.The major respiratory quinone of strain SM1502~T was menaquinone-6(MK-6).Polar lipids of strain SM1502~T mainly included phosphatidylethanolamine(PE)and one unidentified aminolipid and lipid.The genomic DNA G+C content of strain SM1502~T was 37.0 mol%.Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain SM1502~T isolate was affiliated with the genus Flavobacterium,with the highest sequence similarity(96.0%)found with Flavobacterium suzhouense.In the the phylogenetic trees based on 16S rRNA gene sequences,strain SM1502~T formed a separate phylogenetic sub-branch within a sub-clade in the Flavobacterium clade encompassed by six recognized species.Based on the polyphasic taxonomic data,strain SM1502~T represents a novel species of the genus Flavobacterium,for which the name Flavobacterium arcticum sp.nov.is proposed.The type strain of Flavobacterium arcticum is SM1502~T(=KCTC 42668T=CCTCC AB 2015346T).3.Polyphasic taxonomic analysis of strain SM1503~TA Gram-reaction-negative,catalase-and oxidase-positive,rod-shaped bacterium,designated strain SM1503~T,was isolated from surface water of the South China Sea.Strain SM1503~T grew at 8-45? and with 0-7.5%(w/v)NaCl.It reduced nitrate to nitrite and hydrolyzed Tweens 20,40 and 60.The strain contained C17:1?6c,C17:0,C15:0,C18:1?7c,C17:1?8c and C16:0 as the major fatty acids and ubiquinone Q-10 as the major respiratory quinone.Polar lipids of strain SM1503~T comprised phosphatidylethanolamine,phosphatidylglycerol,diphosphatidylglycerol,sphingoglycolipid and phosphatidylcholine.The genomic DNA G+C content of strain SM1503~T was 61.6 mol%.Comparison revealed that strain SM1503~T shared the highest 16S rRNA gene sequence similarities(95.2-95.8%)to the recognized species in the genera Blastomonas and Parablastomonas within the family Sphingomonadaceae.Phylogenetic trees based on 16S rRNA gene sequences showed that strain SM1503~T formed a distinct phylogenetic sub-branch at the root of the sub-cluster comprising the genera Blastomonas and Parablastomonas.On the basis of the phylogenetic,chemotaxonomic and phenotypic data obtained in this study,strain SM1503~T belongs to a new genus in the family Sphingomonadaceae,Pseudoblastomonas gen.nov.,and represents a novel species in the new genus,Pseudoblastomonas maris sp.nov.The type strain of Pseudoblastomonas maris is SM1503~T(= KCTC 42715T = CCTCC AB 2015347T).4.Polyphasic taxonomic analysis of strain SM1504~TA Gram-reaction-negative,aerobic,non-motile and yellow-pigmented bacterium,designated strain SM1504~T,was isolated from Arctic seawater.Strain SM1504~T grew at 4-30? and with 0-4.0%(w/v)NaCl.It hydrolyzed aesculin and gelatin but did not reduce nitrate to nitrite.The major fatty acids of strain SM1504~T were summed feature 3(comprising C16:1?7c and/or iso-C15:02-OH)and iso-C15:0.The predominant polar lipids of strain SM1504~T were phosphatidylethanolamine and one unidentified lipid.The only respiratory quinone detected in strain SM1504~T was menaquinone 7(MK-7).The genomic DNA G+C content of strain SM1504~T was 40.8 mol%.Phylogenetic analysis of 16S rRNA gene sequences revealed that strain SM1504~T constituted a distinct phylogenetic line within the family Cytophagaceae and was closely related to species of the genera Lacihabitans,Emticicia,Fluviimonas and Leadbetterella,with respect to which low sequence similarities between 88.9 and 91.6%were observed.On the basis of the phylogenetic,chemotaxonomic and phenotypic characterization for strain SM1504~T in this study,it belongs to a new genus in the family Cytophagaceae,Arcticibacterium gen.nov.,and represents a novel species in the new genus,Arcticibacterium luteifluviistationis sp.nov.The type strain of Arcticibacterium luteifluviistationis is SM1504~T(= KCTC 42716~T ? CCTCC AB 2015348~T).