Microvirga arsenatis sp. nov., an arsenate reduction bacterium isolated from Tibet hot spring sediments

Microvirga terrestris sp. nov., and Microvirga arvi sp. nov., isolated from soil in South Korea

Two novel Gram-stain-negative, aerobic, rod shaped bacterial strains BT290^T and BT689^T were isolated from soil collected in South Korea. Colony morphologies of both strains were circular and convex while the colors of BT290^T and BT689^T were light-pink and white, respectively. Phylogenetic analysis based on 16S rRNA gene sequences revealed that BT290^T and BT689^T belong to a distinct lineage within the genus Microvirga (family Methylobacteriaceae, order Rhizobiales, class Alphaproteobacteria, phylum Proteobacteria, kingdom Bacteria). The 16S rR NA gene sequence similarity between two strains was 97.9%. Both strains had the similar quinone system, with ubiquinone 10 (Q-10) as the major respiratory quinone. The major polar lipids of strains BT290^T and BT689^T were phosphatidylethanolamine (PE), diphosphatidylglycerol (DPG), phosphatidylcholine (PC), and phosphatidylglycerol (PG). The major cellular fatty acids of strain BT290^T were C_18:1 ω7c (58.2%) and C_16:0 (17.7%), while those of strain BT689^T were C_18:1 ω7c (61.8%) and C_16:0 (10.8%). On the bases of polyphasic analysis (phylogenetic, chemotaxonomic, and biochemical), strains BT290^T and BT689^T can be suggested as novel bacterial species within the genus Microvirga and the proposed names are Microvirga terrestris and Microvirga arvi, respectively. The type strain of Microvirga terrestris is BT290^T (= KCTC 72367^T = NBRC 114844^T) and the type strain of Microvirga arvi is BT689^T (= KACC 22016^T = NBRC 114858^T), respectively.

Thermomonas flagellata sp. nov. and Thermomonas alba sp. nov., two novel members of the phylum Pseudomonadota isolated from hot spring sediments

Two novel species, designated strains SYSU G04041T and SYSU G04536T, were isolated from hot spring sediments collected in Yunnan, PR China. Phenotypic and chemotaxonomic analyses, and whole-genome sequencing were used to determine the taxonomic positions of the candidate strains. Phylogenetic analysis using 16S rRNA gene sequence indicated that strain SYSU G04041T showed the highest sequence similarity to Thermomonas haemolytica A50-7-3T (97.5 %), and SYSU G04536T showed the highest sequence similarity to Thermomonas hydrothermalis SGM-6T (98.2 %). The strains could be differentiated from other species of the genus Thermomonas by their distinct phenotypic and genotypic characteristics. Cells of strains SYSU G04041T and SYSU G04536T were aerobic, motile and Gram-stain-negative. Growth both occurred optimally at 45 °C and pH 7.0 for SYSU G04041T and SYSU G04536T. In addition, the predominant respiratory quinone in both isolates was ubiquinone Q-8. The major fatty acids (>10 %) of strain SYSU G04041T were C16 : 0, iso-C15 : 0 and iso-C16 : 0, while the major fatty acids (>10 %) of strain SYSU G04536T were iso-C15 : 0 and iso-C16 : 0. The main detected polar lipids in strains SYSU G04041T and SYSU G04536T included phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylglycerol. The G+C contents of the genomic DNA of strains SYSU G04041T and SYSU G04536T based on draft genomic sequences were 72.5 and 68.3 %, respectively. On the basis of phenotypic, genotypic and phylogenetic data, strains SYSU G04041T and SYSU G04536T represent two novel species of the genus Thermomonas , for which the names Thermomonas flagellata sp. nov. and Thermomonas alba sp. nov. are proposed, with the type strains SYSU G04041T (=CGMCC 1.19366T=KCTC 92228T) and SYSU G04536T (=CGMCC 1.19367T=KCTC 82839T), respectively.

Microvirga terricola sp. nov. and Microvirga solisilvae sp. nov, isolated from forest soil

Two Gram-staining-negative, aerobic and rod-shaped strains, designated c23x22^T and sex2^T, were isolated from forest soil collected from Chebaling National Nature Reserve in Guangdong Province and Limu Mountain National Forest Park in Hainan Province, P. R. China, respectively. Phylogenetic analyses based on 16S rRNA gene sequences revealed that they belonged to the genus Microvirga, and strain c23 x22^T was most closely related to 'Microvirga alba' KCTC 72385, while strain sex2^T showed close relationship with Microvirga guangxiensis CGMCC 1.7666^T. The average nucleotide identity and digital DNA-DNA hybridization values between strains c23 x22^T and sex2^T and their close relatives, 'M. alba' KCTC 72385 and M. guangxiensis CGMCC 1.7666^T, were all below the threshold values for species delimitation. The predominant quinones of the two novel strains were ubiquinone 10, and the major fatty acids contained C_19:0 cyclo ω8c and summed feature 8 (C_18:1 ω7c and/or C_18:1 ω6c). Their predominant polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylcholine. The phenotypic, genotypic and chemotaxonomic analyses clearly supported that strains c23 x 22^T and sex2^T represent two novel species of the genus Microvirga, for which the name Microvirga terricola sp. nov. (type strain c23 x 22^T = GDMCC 1.1700^T = KCTC 62432^T) and Microvirga solisilvae sp. nov. (type strain sex2^T = GDMCC 1.1651^T = KACC 21311^T) are proposed, respectively.

Microvirga puerhi sp. nov., isolated from Puerh tea garden soil

Strain WGZ8^T was isolated from a soil sample of Puerh tea garden in Pu'er city, Southwest China. The isolate was rod-shaped, Gram-stain negative, facultative anaerobic, non-motile. Growth occurred within 0-3.0% (w/v) NaCl (optimal concentration, 0-1.0%), pH 5.0-11.0 (optimal pH, 7.0) and 10-40 °C (optimal temperature, 28 °C). 16S rRNA gene sequence-based phylogenetic and phylogenomic analysis revealed that WGZ8^T belonged to the genus Microvirga. Its major cellular fatty acids were C_19:0 cyclo ω8c, C_16:0, C_18:1ω7c and/or C_18:1ω6c. The profile of polar lipids included phosphatidyldimethylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylethanolamine, phosphatidylcholine, diphosphatidylglycerol and phosphatidylglycerol. The only respiratory quinone was detected as ubiquinone 10 (Q-10). The genome size of strain WGZ8^T was 5.17 MB, and the content of DNA G + C was 61 mol%. Based on the results of digital DNA-DNA hybridization and phenotypic results, strain WGZ8^T could be concluded as a novel species of the genus Microvirga, for which the name Microvirga puerhi sp. nov. is proposed. The type strain is WGZ8^T (= CGMCC 1.19171 ^T = JCM 35317 ^T).

Microvirga roseola sp. nov. and Microvirga lenta sp. nov., isolated from Taklamakan Desert soil

Two Gram-negative, rod-shaped, non-spore-forming bacteria, designated SM9T and SM2T, were isolated from Taklamakan Desert soil samples. Phylogenetic analysis based on the 16S rRNA gene sequences showed that strains SM9T and SM2T had the highest sequence similarity to the type strains Microvirga indica BCRC 80972T and Microvirga soli NBRC 112417T with similarity values of 98.2 and 97.7 %, respectively, and Microvirga was among the predominant genera in the desert soil. The draft genomes of these two strains were 4.56 Mbp (SM9T) and 5.08 Mbp (SM2T) long with 65.1 mol% (SM9T) and 63.5 mol% (SM2T) G+C content. To adapt to the desert environment, these two strains possessed pathways for the synthesis of stress metabolite trehalose. The major fatty acids (>5 %) included C18 : 1 ω9c in SM2T, but C16 : 0, C18 : 0 and C19 : 0 cyclo ω8c in SM9T, while the major menaquinone was ubiquinone 10 in both strains. The major polar lipids of SM9T and SM2T were phosphatidylglycerol, phosphatidylethanolamine and phospholipid. The average nucleotide identity and digital DNA–DNA hybridization results further indicated that strains SM9T and SM2T were distinguished from phylogenetically related species and represented two novel species within the genus Microvirga , for which the names Microvirga roseola sp. nov. (type strain SM2T=KCTC 72792T=CGMCC 1.17776T) and Microvirga lenta sp. nov. (type strain SM9T=KCTC 82729T=CCTCC AB 2021131T) are proposed.

Rhodoflexus caldus gen. nov., sp. nov., a new member of the phylum Bacteroidota isolated from a hot spring sediment

A thermophilic bacterium, designated strain SYSU G04325^T, was isolated from a hot spring sediment in Yunnan, China. Polyphasic taxonomic analyses and whole-genome sequencing were used to determine the taxonomic position of the strain. Phylogenetic analysis using 16S rRNA gene sequences indicated that strain SYSU G04325^T shows high sequence similarity to Thermoflexibacter ruber NBRC 16677^T (86.2%). The strain can be differentiated from other species of the family Thermoflexibacteraceae by its distinct phenotypic and genotypic characteristics. Cells of the strain SYSU G04325^T were observed to be aerobic, Gram-stain negative and filamentous. Growth was found to occur optimally at 45 ºC and pH 7.0. In addition, the respiratory quinone was identified as menaquinone-7, while the major fatty acids (> 10%) were identified as iso-C_15:0, iso-C_17:0 and Summed Feature 9 (iso-C_17:1ω9c). The polar lipids detected included phosphatidylethanolamine, three unidentified phospholipids, one unidentified glycolipid, five unidentified aminolipids and four unidentified polar lipids. The G + C content of the genomic DNA was determined to be 47.6% based on the draft genome sequence. On the basis of phenotypic, genotypic and phylogenetic data, strain SYSU G04325^T is concluded to represent a novel species of a novel genus in the family Thermoflexibacteraceae, for which the name Rhodoflexus caldus gen. nov., sp. nov. is proposed. The type strain of Rhodoflexus caldus is SYSU G04325^T (= MCCC 1K06127^T = KCTC 82848^T).

Description and genome analysis of Microvirga antarctica sp. nov., a novel pink-pigmented psychrotolerant bacterium isolated from Antarctic soil

A novel pink-pigmented bacterium, designated strain 3D7^T, was isolated during an investigation of potential psychrotolerant species from Antarctic soil. Cells of the isolate were observed to be rod-shaped (0.7-0.9 × 1.0-2.2 µm), Gram-stain negative and non-motile. It was able to grow at 4-32  °C, pH 7.0-10.0 and in the presence of 0-3% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain 3D7^T belongs to the genus Microvirga and was most closely related to 'Microvirga brassicacearum' CDVBN77^T (98.3%), Microvirga subterranea DSM 14364 ^T (96.8%), Microvirga guangxiensis 25B^T (96.5%) and Microvirga aerophila DSM 21344 ^T (96.5%). The predominant quinone was ubiquinone 10 (Q-10), and the major fatty acids were summed feature 8 (C_18:1ω7c and/or C_18:1ω6c) and C_19:0 cyclo ω8c. The predominant polar lipids were phosphatidylcholine and phosphatidylethanolamine. The genomic DNA G + C content of strain 3D7^T was 63.5 mol%. Its genome sequence showed genes encoding phosphatases and lipases. Genetic machinery related to carbohydrate-active enzymes and secondary metabolites were also observed. The average nucleotide identity and digital DNA-DNA hybridization values based on whole genome sequences of strain 3D7^T and its closely related species were below the threshold range for species determination. Phenotypic, chemotaxonomic, phylogenetic and genomic analyses suggested that strain 3D7^T represents a novel species of the genus Microvirga, for which the name Microvirga antarctica sp. nov. is proposed. The type strain is 3D7^T (= CGMCC 1.13821^T = KCTC 72465^T).

Microvirga pudoricolor sp. nov., and Microvirga alba sp. nov., isolated from soil in South Korea

Two novel Gram-stain-negative, aerobic, rod-shaped, circular, convex, light-pink and white-colored bacterial strains BT291^T and BT350^T were isolated from soil collected in Uijeongbu city (37° 44' 55″ N, 127° 2' 20″ E) and Jeju island (33° 22' 48″ N, 126° 31' 48″ E), respectively, South Korea. Phylogenetic analysis based on 16S rRNA gene sequences revealed that each of the strains BT291^T and BT350^T belong to a distinct lineages within the genus Microvirga (family Methylobacteriaceae, order Rhizobiales, class Alpha Proteobacteria, phylum Proteobacteria, kingdom Bacteria). The 16S rRNA gene sequence similarity between the two strains BT291^T and BT350^T was 97.4%. The two strains were found to have the same quinone system, with Q-10 as the major respiratory quinone. The major polar lipids of strains BT291^T and BT350^T were phosphatidylethanolamine (PE), diphosphatydilglycerol (DPG), phosphatidylcholine (PC) and phosphatidylglycerol (PG). The major cellular fatty acids of strain BT291^T were C_18:1 ω7c (58.2%) and cyclo-C_19:0 ω8c (25.7%). The major cellular fatty acids of strain BT350^T were C_18:1 ω7c (38.5%) and cyclo-C_19:0 ω8c (27.7%). Based on the polyphasic analysis (phylogenetic, chemotaxonomic and biochemical), strains BT291^T and BT350^T can be suggested as two novel bacterial species within the genus Microvirga and the proposed names are Microvirga pudoricolor and Microvirga alba, respectively. The type strain of Microvirga pudoricolor is BT291^T (= KCTC 72368^T = NBRC 114845^T) and the type strain of Microvirga alba is BT350^T (= KCTC 72385^T = NBRC 114848^T).

Draft genome and description of Microvirga mediterraneensis strain Marseille-Q2068T sp. nov., a new bacterium isolated from human healthy skin

In 2019, by culturing a skin swab from the forehead of a 70-year-old healthy woman via the culturomics method, we isolated the new bacterial strain Marseille-Q2068T (= CSUR-Q2068). Matrix-assisted desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) failed to identify this isolate. Analysis of the 16S ribosomal RNA gene and genome-to-genome comparison suggested that this taxon belongs to a novel bacterial species within the family Methylobacteriaceae in the phylum Proteobacteria. We describe here its main phenotypic characteristics, genome sequence and annotation of Microvirga mediterraneensis strain Marseille-Q2068T, a new member of the Microvirga genus, which we propose as the type strain.