Draconibacterium aestuarii sp.nov., a Glycolipid-Producing Bacterium Isolated from Tidal Flat Sediment and Emended Description of the Genus Draconibacterium.

A facultatively anaerobic, Gram-negative, curved rod-shaped bacterium (4.0-17.0 µm long, 0.6-0.9 µm wide), designated Z1-6T, was obtained from tidal flat sediment collected from YueAo village in Zhoushan, Zhejiang, People's Republic of China. Strain Z1-6T occurred at 15-45 °C (optimum 28-32 °C), pH 6.0-9.0 (optimum 7.0-7.5), and in the presence of 1-5% (w/v) NaCl (optimum 1-2%). The strain contained iso-C15:0 and antesio-C15:0 as the major fatty acids. An unsaturated menaquinone with seven isoprene units (MK-7) was the predominant respiratory quinone. The polar lipids included phosphatidylethanolamine (PE), one aminophospholipid (APL), two phospholipids (PL1 and PL2), three glycolipids (GL1, GL2, and GL3), and two unidentified lipids (L1 and L2). The genomic DNA G+C content of strain Z1-6T was 39.2%, and the genome size was 6.4 Mb. The strain showed the highest average nucleotide identity (ANI) value of 73.5-74.6%, digital DNA-DNA hybridization (dDDH) value of 19.3-20%, average amino acid identity (AAI) value of 72.0-73.1% with the members of genus Draconibacterium. Phylogenetic analysis based on 16S rRNA gene sequences and genome revealed that strain Z1-6T formed a distinct branch in the clade of the genus Draconibacterium. Based on the phenotypic, phylogenetic, chemotaxonomic analyses and genomic data, strain Z1-6T represents a novel species of the genus Draconibacterium, for which the name Draconibacterium aestuarii sp. nov. (The type strain Z1-6T = MCCC 1K07533T = KCTC 92310T) is proposed.

Flagellimonas baculiformis sp. nov. and Flagellimonas crocea sp. nov., isolated from surface seawater of the Pacific Ocean.

Two Gram-negative, non-spore-forming, non-motile, non-flagellated bacteria, designated strains D6T and DH64T, were isolated from surface water of the Pacific Ocean. For strain D6T, growth occurred at 10-40 °C, pH 5.5-9.0 and in the presence of 0-8.0 % NaCl (w/v). For strain DH64T, growth occurred at 10-40 °C, pH 5.5-8.5 and in the presence of 0.5-8.0 % NaCl (w/v). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strains D6T and DH64T both belonged to the genera Flagellimonas, with the highest sequence identities to Flagellimonas taeanensis JCM 17757T (98.2 %) and Flagellimonas marinaquae JCM 11811T (98.6 %), respectively. The 16S rRNA gene sequence identity between strains D6T and DH64T was 95.9 %. The average amino acid identity and digital DNA-DNA hybridization values between the two strains and the nearest phylogenetic neighbours were 66.7-93.3 % and 16.1-38.5 %, respectively. The major respiratory quinone of both strains was menaquinone-6. The major polar lipid was phosphatidylethanolamine. The major fatty acids were identified similarly as iso-C15 : 1 G, iso-C15 : 0 and iso-C17 : 0 3-OH. The genomic G+C contents of strains D6T and DH64T were determined to be 45.5 and 42.6 mol%, respectively. The combined genotypic and phenotypic data show that the strains represent two novel species within genera Flagellimonas, for which the names Flagellimonas baculiformis sp. nov. and Flagellimonas crocea sp. nov. are proposed, with type strains D6T (=MCCC M28982T=KCTC 92604T) and DH64T (=MCCC M28986T=KCTC 92975T).

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

Two Gram-stain-negative, rod-shaped and non-motile strains, designated as DY56-A-20T and G39T, were isolated from deep-sea sediment of the Pacific Ocean and deep-sea seawater of the Indian Ocean, respectively. Strain DY56-A-20T 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 G39T 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-20T had the highest sequence identity with Qipengyuania marisflavi KEM-5T (97.6 %), while strain G39T displayed the highest sequence identity with Qipengyuania citrea H150T (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-20T/G39T 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-20T and G39T, respectively. The predominant cellular fatty acids (>10 %) of strain DY56-A-20T were C17 : 1 ω6c, summed feature 8 and summed feature 3, and the major cellular fatty acids of strain G39T were C17 : 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-20T (=MCCC M27941T=KCTC 92309T), and the type strain of Q. profundimaris is G39T (=MCCC M30353T=KCTC 8208T).

Metagenome-based analysis of carbon-fixing microorganisms and their carbon-fixing pathways in deep-sea sediments of the southwestern Indian Ocean.

Carbon fixation by chemoautotrophic microorganisms in the dark ocean makes a large contribution to oceanic primary production and the global carbon cycle. In contrast to the Calvin cycle-dominated carbon-fixing pathway in the marine euphotic zone, carbon-fixing pathways and their hosts in deep-sea areas are diverse. In this study, four deep-sea sediment samples close to hydrothermal vents in the southwestern Indian Ocean were collected and processed using metagenomic analysis to investigate carbon fixation potential. Functional annotations revealed that all six carbon-fixing pathways had genes to varied degrees present in the samples. The reductive tricarboxylic acid cycle and Calvin cycle genes occurred in all samples, in contrast to the Wood-Ljungdahl pathway, which previous studies found mainly in the hydrothermal area. The annotations also elucidated the chemoautotrophic microbial members associated with the six carbon-fixing pathways, and the majority of them containing key carbon fixation genes belonged to the phyla Pseudomonadota and Desulfobacterota. The binned metagenome-assembled genomes revealed that key genes for the Calvin cycle and the 3-hydroxypropionate/4-hydroxybutyrate cycle were also found in the order Rhodothermales and the family Hyphomicrobiaceae. By identifying the carbon metabolic pathways and microbial populations in the hydrothermal fields of the southwest Indian Ocean, our study sheds light on complex biogeochemical processes in deep-sea environments and lays the foundation for further in-depth investigations of carbon fixation processes in deep-sea ecosystems.

Membranihabitans maritimus sp. nov., a marine bacterium isolated from deep seawater.

A Gram-stain-negative, non-motile, rod-shaped bacterial strain, designated C281T, was isolated from seawater sampled at the Marshallese seamount chain. Results of 16S rRNA gene analysis revealed that strain C281T was most closely related to Membranihabitans marinus CZ-AZ5T with 92.7 % sequence similarity. Phylogenetic analysis indicated that the new isolate represented a novel species by forming a distinctive lineage within the family Saprospiraceae. The DNA G+C content of strain C281T was 38.4 mol%. The genome sizes of strain C281T and the reference strain M. marinus CZ-AZ5T were 5 962 917 and 5 395 999 bp, respectively. The average nucleotide identity and in silico DNA-DNA hybridization values between strains C281T and M. marinus CZ-AZ5T were found to be low (69.3 and 17.6 %, respectively). Different functional genes were found in the genome of strain C281T, such as CZC CBA, polysaccharide utilization loci and linear azol(in)e-containing peptide cluster coding genes. The NaCl range for growth was 0.5-15.0 %. Positive results were obtained for hydrolysis of Tween 60 and urease. MK-7 was the sole respiratory quinone. The major fatty acids were C16 : 1 ω6c and/or C16 : 1 ω7c, iso-C15 : 0 and iso-C15 : 1 F. The major polar lipids of strain C281T were phosphatidylethanolamine, phosphatidylglycerol, two unidentified lipids and five unidentified glycolipids. On the basis of its taxonomic characteristics, the isolate represents a novel species of the genus Membranihabitans, for which the name Membranihabitans maritimus sp. nov. (type strain C281T=KCTC 92171T=MCCC M27001T) is proposed.

Aestuariibaculum sediminum sp. nov., a marine bacterium isolated from a tidal flat in Zhoushan.

A Gram-staining-negative, non-motile, strictly aerobic bacterium, designated as strain TT11T, was isolated from a sediment sample of a tidal flat connected in Zhoushan, China. Cells of strain TT11T are spherical, halotolerant, catalase- and oxidase-positive, and produce carotenoid-like pigments. Colonies were 0.5-1.0 mm diameter, smooth, round, convex and orange-yellow after growth on marine agar at 30 °C for 24 h. Growth of the strain TT11T was observed at 10-40 °C (optimum, 35 °C), at pH 6.0-9.5 (optimum, pH 6.5), and in the presence of 0-8.0% (w/v) NaCl (optimum, 0.5-1.0%). The results of 16S rRNA gene sequence analysis revealed that strain TT11T represents a member of the genus Aestuariibaculum and was closely related to Aestuariibaculum suncheonense SC17T (97.2%) and Aestuariibaculum marinum IP7T (96.8%). The G + C content of the genome was 34.6%. The only respiratory quinone was MK-6. The major fatty acids (> 10%) were iso-C15:0, iso-C15:1 G and iso-C17:0 3-OH. The major polar lipids contained phosphatidylethanolamine, phosphoglycolipid, four unidentified aminolipids, four unidentified lipids and two unidentified glycolipids. On the basis of these genomic, chemotaxonomic and phenotypic characteristics, we propose a novel species Aestuariibaculum sediminum sp. nov. with the type strain TT11T (= KCTC 82195T = MCCC 1K04734T).

Micromonospora zhangzhouensis sp. nov., a Novel Actinobacterium Isolated from Mangrove Soil, Exerts a Cytotoxic Activity in vitro.

A new bacterial strain, designated HM134T, was isolated from a sample of soil collected from a Chinese mangrove Avicennia marina forest. Assessed by a polyphasic approach, the taxonomy of strain HM134T was found to be associated with a range of phylogenetic and chemotaxonomic properties consistent with the genus Micromonospora. Phylogenetic analysis based on the 16s rRNA gene sequence indicated that strain HM134T formed a distinct lineage with the most closely related species, including M. rifamycinica AM105T, M. wenchangensis CCTCC AA 2012002T and M. mangrovi 2803GPT1-18T. The ANI values between strain HM134T and the reference strains ranged from 82.6% to 95.2%, which was below the standard criteria for classifying strains as the same species (96.5%). Strain HM134T and related species shared in silico dDDH similarities values below the recommended 70% cut-off for the delineation of species (range from 25.7-62.6%). The DNA G+C content of strain HM134T was 73.2 mol%. Analysis of phylogenetic, genomic, phenotypic and chemotaxonomic characteristics revealed that strain HM134T is considered to represent a novel species of the genus Micromonospora, for which the name M. zhangzhouensis sp. nov. is proposed. The extract of strain HM134T was demonstrated to exhibit cytotoxic activity against the human cancer cell lines HepG2, HCT-116 and A549. Active substance presented in the fermentation broth of strain HM134T was isolated by bioassay-guided analysis and purified afterwards. A new derivative of diterpenoid was identified through electrospray ionizing mass spectrometry (MS) and nuclear magnetic resonance (NMR). The compound showed different cytotoxic activities against cancer cells, with the highest cytotoxicity against HCT-116, corresponding to IC50 value of 38.4 µg/mL.

Nesterenkonia muleiensis sp. nov., a novel actinobacterium isolated from sap of Populus euphratica.

A novel, Gram-stain-positive, aerobic, non-endospore-forming, non-motile and rod-shaped bacterium designated RB2T was isolated from sap of Populus euphratica collected in Mulei county, Xinjiang province, PR China. RB2T was able to grow at 10-45 °C (optimum 35 °C), pH 6.0-12.0 (optimum 8.0) and with 0-12 % (w/v) NaCl (optimum 1 %). The genomic DNA G+C content was 63.5 % (from the genome sequence). The results of the chemotaxonomic analysis indicated that the predominant isoprenoid quinones were MK-8 and MK-9. The major fatty acids were anteiso-C15 : 0 and anteiso-C17 : 0. The major polar lipids of RB2T were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and two glycolipids. The peptidoglycan type of RB2T was A4α, l-Lys-Gly-l-Glu. The results of the phylogenetic analysis, along with the phenotypic and chemotaxonomic characteristics, indicate that strain RB2T represents a novel species of the genus Nesterenkonia, for which the name Nesterenkonia muleiensis sp. nov. is proposed. The type strain is RB2T (=MCCC 1K03528T=KCTC 49017T).

The Complete Genome of Emcibacter congregatus ZYLT, a Marine Bacterium Encoding a CRISPR-Cas 9 Immune System.

Emcibacter congregatus ZYLT was isolated from a sediment sample cultured in situ in a coast located in the East China Sea. The genome of E. congregatus ZYLT was sequenced and assembled into one single circular chromosome with the size of 4,189,011 bp and G+C content of 52.6%. Genomic annotation showed that E. congregatus ZYLT had an intact Type II-C CRISPR-Cas system consists of three cas genes (cas 9, cas 1, and cas 2), 34 direct repeat sequences with the length of 36 bp, and 33 spacers. The predicted Cas 9 protein was smaller than most of existing genome editing tools. This structure might have potential in developing new gene editing system and uncovering the regulatory mechanisms of CRISPR-Cas system. Besides, the comparison between E. congregatus ZYLT and its relative species living in neritic environments unraveled some common traits of the defective strategies of these bacteria to face inshore challenges including the motility, multidrug resistance, and universal efflux pumps.

Idiomarina mangrovi sp. nov., isolated from rhizosphere soil of a mangrove Avicennia marina forest.

A Gram-staining negative, aerobic, motile and rod-shaped bacterium, designated ZQ330T, was isolated from rhizosphere soil of a mangrove (Avicennia marina) forest of Zhangzhou, Fujian Province, China. The growth range of NaCl concentration was 0.5-10.0 % (w/v), with an optimum at 2.5-3.0 % (w/v), the temperature range for growth was 10-40 °C, with an optimum at 28-30 °C, the pH range for growth was pH 6.0-9.5, with an optimum at pH 7.5. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain ZQ330T exhibited less than 97.0 % sequence similarity to all type strains with validly published names and revealed that strain ZQ330T formed a distinct lineage in the genus Idiomarina. The average nucleotide identity, and in silico DNA-DNA hybridization values between strain ZQ330T and the reference strains were 64.8-69.9 % and 27.5-28.4 %, respectively. Chemotaxonomic analysis indicated that the main respiratory quinone was Q-8, the predominant cellular fatty acids were iso-C15 : 0, iso-C17 : 0, summed feature 9 (C16 : 0 10-methyl and/or iso-C17 : 1ω9c), iso-C15 : 1F, C16 : 0, C18 : 0, summed feature 3 (C16 : 1ω8c and/or iso-C16 : 1 2-OH) and summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c). The polar lipid profile was composed of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, an unidentified glycolipid, an unidentified aminolipid, an unidentified phospholipid and two unidentified lipids. Based on the genotypic, phenotypic, chemotaxonomic and phylogenetic features, strain ZQ330T is considered to represent a novel species, for which the name Idiomarina mangrovi sp. nov. is proposed. The type strain is ZQ330T (=MCCC 1K03495T=KCTC 62455T).

Marortus luteolus gen. nov., sp. nov., isolated from surface seawater of the East Sea in China.

A Gram-stain-negative, motile, aerobic, rod-shaped bacterium with flagella, designated ZX-21T, was isolated from surface seawater of the East Sea in Zhoushan, China. Growth of strain ZX-21T was observed at 10--35 o°C (optimum, 30 °C), at pH 6.0-8.5 (pHoptimum 6.5-7.0) and in the presence of 0.5-8 % (w/v) NaCl (optimum 3-4 %). It was positive for oxidase and catalase activity. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain ZX-21T constituted an independent lineage within the family Spongiibacteraceae and was most closely related to Zhongshania guokunii (96.83 %). Strain ZX-21T contained ubiquinone-8 (Q-8) as the sole isoprenoid quinone and summed feature 3 (C16 : 1ω77c and/or C16 : 1ω66c), summed feature 8 (C18 : 1ω77c and/or C18 : 1ω66c) and C16 : 0 as the major fatty acids. Phosphatidylglycerol (), phosphatidylethanolamine (), diphosphatidylglycerol () and an unidentified glycolipid were the major cellular polar lipids. The DNA G+C content was 49.1 mol%. Based on itsthe morphological, physiological and chemotaxonomic characteristics, strain ZX-21Tis described as a novel species in a novel genus for whichwith the name Marortus luteolus gen. nov., sp. nov. (type strain ZX-21T = MCCC 1K03431T=KCTC 62160T) is proposed.

Azoarcus pumilus sp. nov., isolated from seawater in Sanya, China.

A novel Gram-stain-negative, motile, rod-shaped (0.4-0.5×1.0-2.0 µm) strain with one polar flagellum, designated SY39T, was isolated from seawater in Sanya, China. Strain SY39T was able to grow at 15-40 °C (optimum, 35-37 °C), pH 6.5-8.5 (pH 8.0) and 0.5-6.0 % (w/v) NaCl (3.5 %). Chemotaxonomic analysis showed that the isoprenoid quinones were Q-8 (88.6 %) and Q-7 (11.4 %). The dominant fatty acids were C16 : 0 and summed feature 3 (C16 : 1ω7c/C16 : 1ω6c). The polar lipids of strain SY39T consisted of diphosphatidyglycerol, phosphatidylglycerol, phosphatidylethanolamine, one unknown phosphoglycolipid, one unknown glycolipid and two unknown aminophosphoglycolipids. The DNA G+C content of the genomic DNA was 66.5 mol%. The phylogenetic analysis of 16S rRNA gene sequences showed that strain SY39T belongs to the genus Azoarcus with similarity ranging from 92.3 to 95.2 %. Based on the phenotypic, chemotaxonomic and phylogenetic features, strain SY39T is concluded to represent a novel species of the genus Azoarcus, for which the name Azoarcus pumilus sp. nov. is proposed. The type strain is SY39T (=KCTC 62157T=MCCC 1K03430T).

Emcibacter congregatus sp. nov., isolated from sediment cultured in situ.

A Gram-negative, aerobic, motile, rod-shaped, pale-yellow bacterial strain, designated as ZYLT, isolated from a cultured in situ sediment sample collected from the East China Sea coast, was studied using a polyphasic taxonomic approach. Strain ZYLT grew at 4-30 °C (optimum, 25 °C), at pH 6.0-8.5 (pH 7.0) and with 0-7.0 % (w/v) NaCl (2.0 %). Results of phylogenetic analysis based on 16S rRNA gene sequences clearly showed that strain ZYLT and Emcibacter nanhaiensis HTCJW17T, which was most closely related to strain ZYLT with 93.6 % sequence similarity, clustered together. The genomic DNA G+C content was 51.5 % (genome sequence). The quinone system was composed only of ubiquinone-10. Strain ZYLT possessed C18 : 1ω7c and/or C18 : 1ω6c (summed feature 8), iso-C15 : 0 2-OH and/or C16 : 1ω7c (summed feature 3), C14 : 0 2-OH and C14 : 0 as the major fatty acids. The content of summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c) in strain ZYLT was far greater than that in E. nanhaiensis. The polar lipid profile consisted of phosphatidylethanolamine, phosphatidylglycerol, three unidentified aminophospholipids, three unidentified phospholipids, one unidentified aminolipid and four unidentified lipids. One unidentified aminophospholipid and two unidentified lipids present in strain ZYLT were not found in E. nanhaiensis in this research. On the basis of phenotypic, phylogenetic and chemotaxonomic data, strain ZYLT (=KCTC 62328T=JCM 32378T=MCCC 1K03526T) represents a novel species of the genus Emcibacter for which the name Emcibacter congregatus sp. nov. is proposed.

Agromyces mangrovi sp. nov., a Novel Actinobacterium Isolated from Mangrove Soil.

A novel, Gram-stain-positive, microaerophilic to aerobic, non-endospore-forming, no-motile and rod-shaped bacterium designated Q14T was isolated from mangrove soil samples collected on chengmai, Hainan province, China. Strain Q14T was able to grow at 10-40 °C (optimum 30 °C), pH 5.5-10.0 (optimum 6.5-8.0) and with 0.5-6% (w/v) NaCl (optimum 1%). The genomic DNA G+C content was 70.1%. The chemotaxonomic analysis showed that the predominant isoprenoid quinone was MK-12 and the major fatty acids were anteiso-C15:0, iso-C17:0 and anteiso-C17:0. The major polar lipids of strain Q14T were diphosphatidylglycerol, phosphatidylglycerol and one glycolipid. The strain Q14T contained 2,4-diaminobutylic acid (A2bu), alanine acid, glutamic acid and glycine in the peptidoglycans. The phylogenetic analysis and DNA-DNA hybridization, along with the phenotypic and chemotaxonomic characteristics, indicate that strain Q14T as a novel species of the genus Agromyces, for which the name Agromyces mangrovi sp. nov. is proposed. The type strain is Q14T (= MCCC 1K03191T = KCTC 39814T).

Marinicaulis flavus gen. nov., sp. nov., a novel stalked bacterium of the family Parvularculaceae.

A Gram-stain-negative, aerobic, ovoid or short rod-shaped bacterium with prosthecates and flagella, designated SY-3-19T, was isolated from the surface seawater of the South China Sea, and subjected to a polyphasic taxonomic study. The isolate grew at 4-40 °C and pH 5.0-9.0 (optimum 28 °C and pH 6.5-7.5), and with 0.5-16.0 % (w/v) NaCl (optimum 4 %). It was positive for oxidase and catalase activity. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain SY-3-19T constituted a separate branch in the family Parvularculaceae, sharing the highest sequence similarities to the genera Aquisalinus (91.9 %), Amphiplicatus (91.1 %) and Parvularcula(91.0-89.4 %). The sole respiratory quinone was ubiquinone-10 and the principal fatty acids (>10 %) were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), 11 methyl C18 : 1ω7c and C16 : 0. The polar lipids of strain SY-3-19T consisted of phosphatidylglycerol, nine unidentified glycolipids and four unidentified lipids. The DNA G+C content was 60.9 mol%. On the basis of morphological, physiological and chemotaxonomic characteristics, together with the results of phylogenetic analysis, strain SY-3-19T is described as a novel species in a novel genus, for which the name Marinicaulis flavus gen. nov., sp. nov. (type strain SY-3-19T=MCCC 1K03432T=KCTC 62156T) is proposed.

Halomonas endophytica sp. nov., isolated from liquid in the stems of Populus euphratica.

A Gram-stain-negative, aerobic, motile and rod-shaped bacterium, designated MC28T, was isolated from storage liquid collected from the stems of Populus euphratica in the Xinjiang province of China. The growth range of NaCl concentration was 0.5-6.0 % (w/v), with an optimum at 3.0 % (w/v), the temperature range for growth was 10-45 °C, with an optimum at 40 °C, and the pH range for growth was 6.0-9.0, with an optimum around pH 8.5. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain MC28T formed a distinct lineage in the clade of genus Halomonas and is closely related to Halomonas desiderata DSM 9502T (96.4 %), Halomonas heilongjiangensis DSM 26881T (96.2 %) and Halomonas urumqiensis JCM 30202T (95.2 %). The average nucleotide identity, average amino acid identity and in silico DNA-DNA hybridization values between strain MC28T and the references strains were 77.2-80.3, 65.8-76.8 and 21.6-25.6 %, respectively. Chemotaxonomic analysis indicated that the main respiratory quinones were Q-9 and Q-8, the predominant cellular fatty acids were summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C16 : 1ω9c, C16 : 0 and C17 : 1ω9c, the major polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, phosphatidylinositol, phosphatidylinositol mannoside, an aminophospholipid, an unidentified phospholipid, an unidentified aminolipid and two unidentified lipids. Based on its phenotypic, chemotaxonomic and phylogenetic characteristics, strain MC28T is considered to represent a novel species, for which the name Halomonas endophytica sp. nov. is proposed. The type strain is MC28T (=KCTC 52999T=MCCC 1K03343T).

Aestuarium zhoushanense gen. nov., sp. nov., Isolated from the Tidal Flat.

A gram-stain-negative, aerobic, ovoid or short rod-shaped, and non-motile strain, designed G7T was isolated from a tidal flat sample collected from the coast of East Sea in Zhoushan, China. Strain G7T grew at 4-40 °C and pH 6.0-9.0 (optimum, 28 °C and pH 7.5) and with 0-7% (w/v) NaCl (optimum, 1%). The predominant respiratory quinone was Q-10 and the major fatty acids (>10%) identified were C18:1 ω7c, C16:0 and summed feature 3 (C16:1 ω7c and/or C16:1 ω6c). The polar lipids of strain G7T consisted of phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, and four unidentified lipids. The genomic DNA G+C content was 56.7 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain G7T formed a distinct lineage belonging to the Roseobacter clade of the family Rhodobacteraceae. On the basis of morphological, physiological, and chemotaxonomic characteristics, together with the results of phylogenetic analysis, strain G7T is described as a novel species in a new genus, for which the name Aestuarium zhoushanense gen. nov., sp. nov. (type strain G7T = MCCC 1K03229T = KCTC 52584T) is proposed.

Hyphococcus flavus gen. nov., sp. nov., a novel alphaproteobacterium isolated from deep seawater.

A Gram-staining-negative, aerobic, non-spore-forming, coccoid to rod shaped bacteria with prosthecate and flagellum, designated as HSF6T, was isolated from deep seawater samples collected from the South China Sea at depth of 2.5 km and subjected to a polyphasic taxonomic investigation. Colonies of strain HSF6T were 1-2 mm in diameter, smooth, circular, convex and yellow. Strain HSF6T was found to grow at 15-37 °C (optimum, 25-35 °C), pH 5.0-9.5 (optimum, pH 7.0-7.5) and with 0-8 % (w/v) NaCl (optimum, 2 %). Chemotaxonomic analysis showed the predominant respiratory quinone of strains HSF6T were ubiquinone-10, and the major fatty acids were C18 : 1ω7c, C16 : 0 and 11-methyl C18 : 1ω7c. The polar lipids were monoglycosyldiglyceride (MGDG), sulfo-quinovosyl diacylglycerol (SQDG), three unknown glycolipids (GL1-3) and five unknown lipids (L1-5). The DNA G+C content of strain HSF6T was determined to be 51.0 mol% with HPLC. The comparison of 16S rRNA gene sequence similarities show that strain HSF6T was related most closely to genus Parvularcula with similarity ranging from 91.0 to 91.8 %. The phylogenetic trees, using the 16S rRNA gene sequence, reconstructed with neighbour-joining, maximum-parsimony and maximum-likelihood methods showed that strain HSF6T constituted a separated branch in the family 'Parvularculaceae'. Differential phenotypic properties, together with the phylogenetic distinctiveness, demonstrated that strain HSF6T is clearly distinct from validly published genera. On the basis of these features, we propose strain HSF6T (=MCCC 1K03223T=KCTC 52486T) represents a novel species of a novel genus with the name Hyphococcus flavus gen. nov., sp. nov.

Mesorhizobium oceanicum sp. nov., isolated from deep seawater.

A novel Gram-staining-negative, oval-shaped (0.4-0.6×0.8-1.0 µm), non-motile strain without flagella, designated B7T, was isolated from deep seawater in the South China Sea. Strain B7T was able to grow at 25-40 °C (optimum 35 °C), at pH 5.5-9.0 (optimum pH 7.0) and with 0-8 % (w/v) NaCl (optimum 3 %). Chemotaxonomic analysis showed that the predominant isoprenoid quinone was Q-10 and the dominant fatty acids were C19 : 0 cyclo 8c and summed feature 8 (C18 : 1ω7c/C18 : 1ω6c). The polar lipids of strain B7T were diphosphatidyglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, one unknown aminophospholipid, one unknown glycolipid and three unknown lipids. The DNA G+C content of the genomic DNA was 65.1 mol%. Phylogenetic analysis of 16S rRNA gene sequences showed that strain B7T belongs to the genus Mesorhizobium with similarities ranging from 96.2 to 97.5 %. Phylogenetic analyses of housekeeping genes recA, atpD and glnII indicated that strain B7T represented a distinct evolutionary lineage with the genus Mesorhizobium. OrthoANI values between strain B7T and related strains of the genus Mesorhizobium (<80 %) were lower than the threshold value of 95 % ANI relatedness for species demarcation. Therefore, strain B7T is concluded to represent a novel species of the genus Mesorhizobium, for which the name Mesorhizobium oceanicumsp. nov. is proposed. The type strain is B7T (=KCTC 42783T=MCCC 1K02305T).

Hyphobacterium vulgare gen. nov., sp. nov., a novel alphaproteobacterium isolated from seawater.

A Gram-stain-negative, aerobic, non-spore-forming, non-motile, oval to rod-shaped, prosthecate bacterium, designated strain WM6T, was isolated from a seawater sample collected from the South China Sea at a depth of 150 m and subjected to a polyphasic taxonomic investigation. Cells of strain WM6T were approximately 0.5-0.6 µm in width and 0.8-1.2 µm in length, and colonies were smooth, circular, convex and whitish yellow. Strain WM6T was found to grow at 10-45 °C (optimum, 30 °C), at pH 6.5-9.0 (optimum, pH 7.5-8.5) and with 1-6 % (w/v) NaCl (optimum, 1-2 %). Chemotaxonomic analysis showed the predominant respiratory quinone and the major fatty acid of strains WM6T were ubiquinone-10 and C18 : 1ω7c, respectively. The polar lipids of strain WM6T were phosphatidylglycerol, glucuronopyranosyldiglyceride, monoglycosyldiglyceride, sulfo-quinovosyl diacylglycerol, seven unknown glycolipids and two unknown lipids. The DNA G+C content of strain WM6T was determined to be 59.8 mol% by HPLC. 16S rRNA gene sequence similarities showed that strain WM6T was related most closely to the genus Maricaulis with a similarity range from 92.3 to 93.8 %. Phylogenetic trees reconstructed with the neighbour-joining and maximum-likelihood methods using mega and maximum-likelihood methods using arb showed that strain WM6T constituted a separated branch in the family Hyphomonadaceae. Differential phenotypic properties, together with phylogenetic distinctiveness, demonstrated that strain WM6T is clearly distinct from any validly published genus. On the basis of these features, strain WM6T represents a novel species of a new genus with the name Hyphobacterium vulgare gen. nov., sp. nov. The type strain of Hyphobacterium vulgare is WM6T (=MCCC 1K03222T=KCTC 52487T).