Sphingomonas Immobilis sp. nov., and Sphingomonas natans sp. nov. bacteria isolated from soil.

Two novel strains of bacteria, CA1-15T and BIUV-7T, were isolated from soil samples gathered in Cheonan-si, Republic of Korea, and Inje-gun, Republic of Korea, respectively. These bacteria are Gram-negative, aerobic, and non-motile. Phylogenetic evaluations, using the sequence of the 16S rRNA gene, showed that strains CA1-15T and BIUV-7T belong to a distinctive clade within the family Sphingomonadaceae (order Sphingomonadales, class Alphaproteobacteria). The strains exhibited the highest similarity in their genetic makeup with representatives of the genus Sphingomonas. Strain CA1-15T was closely related to Sphingomonas echinoides NRRL B-3126T (97.8% similarity in 16S rRNA gene sequence), Sphingomonas oligophenolica JCM 12,082T (97.8%), Sphingomonas glacialis C16yT (97.6%) and Sphingomonas psychrolutea MDB1-AT (97.3%). Strain BIUV-7T was closely related to Sphingomonas nostoxanthinifaciens AK-PDB1-5T (97.0%), Sphingomonas vulcanisoli SN6-13T (96.3%), Sphingomonas naphthae DKC-5-1T (96.2%), and Sphingomonas prati W18RDT (95.7%). The optimal growth conditions for strains CA1-15T and BIUV-7T were determined to be at pH 7.0 and a temperature of 25 °C. Analysis of the cellular fatty acids of strain CA1-15T and BIUV-7T revealed that summed feature 8 (C18:1ω7c/C18:1ω6c) (60.4%), summed feature 8 (C18:1ω7c/C18:1ω6c) (62.9%) were the major component, respectively. Additionally, both strains exhibited ubiquinone Q-10 as their major respiratory quinone, and diphosphatidylglycerol (DPG), glycosphingolipid (SGL), and phosphatidylethanolamine (PE) as the major polar lipid. The genome of strain CA1-15T measures 4,133,944 bp, comprising 4,026 coding sequences (CDSs) and 46 tRNA genes. Similarly, the genome of strain BIUV-7T is 4,563,252 bp, characterized by 4,226 CDSs and 44 tRNA genes. The average nucleotide identity (ANI) analysis and digital DNA-DNA hybridization (dDDH) values between strain CA1-15T and other Sphingomonas species range from 73.2 to 79.9% and 19.4-22.9%, respectively. Comparatively, ANI and dDDH values between strain BIUV-7T and other Sphingomonas species are in the range of 72.9-76.5% and 19.3-20.9%, respectively. Based on the biochemical, chemotaxonomic, and phylogenetic analyses, it is evident that strains CA1-15T and BIUV-7T represent two novel bacterial species within the genus Sphingomonas. Accordingly, the names Sphingomonas immobilis sp. nov. and Sphingomonas natans sp. nov. are proposed. also, CA1-15T(= KCTC 92960T = NBRC 116547T) is the type strain of Sphingomonas immobilis and BIUV-7T(= KCTC 92961T = NBRC 116546T) is the type strain of Sphingomonas natans.

Sphingomonas lacusdianchii sp. nov., an attached bacterium inhibited by metabolites from its symbiotic cyanobacterium.

An alpha-proteobacterial strain JXJ CY 53 T was isolated from the cyanosphere of Microcystis sp. FACHB-905 (MF-905) collected from Lake Dianchi, China. JXJ CY 53 T was observed to be an aerobic, Gram-stain-negative, oval shaped, and mucus-secreting bacterium. It had C18:1ω7c and C16:0 as the major cellular fatty acids, Q-10 as the predominant ubiquinone, and sphingoglycolipid, diphosphatidylglycerol, phosphatidylcholine, and phosphatidylmethylethanolamine as the polar lipids. The G + C content of DNA was 65.85%. The bacterium had 16S rRNA gene sequence identities of 98.9% and 98.7% with Sphingomonas panni DSM 15761 T and Sphingomonas hankookensis KCTC 22579 T, respectively, while less than 97.4% identities with other members of the genus. Further taxonomic analysis indicated that JXJ CY 53 T represented a new member of Sphingomonas, and the species epithet was proposed as Sphingomonas lacusdianchii sp. nov. (type strain JXJ CY 53 T = KCTC 72813 T = CGMCC 1.17657 T). JXJ CY 53 T promoted the growth of MF-905 by providing bio-available phosphorus and nitrogen, plant hormones, vitamins, and carotenoids. It could modulate the relative abundances of nonculturable bacteria associated with MF-905 and influence the interactions of MF-905 and other bacteria isolated from the cyanobacterium, in addition to microcystin production characteristics. Meanwhile, MF-905 could provide JXJ CY 53 T dissolved organic carbon for growth, and control the growth of JXJ CY 53 T by secreting specific chemicals other than microcystins. Overall, these results suggest that the interactions between Microcystis and its attached bacteria are complex and dynamic, and may influence the growth characteristics of the cyanobacterium. This study provided new ideas to understand the interactions between Microcystis and its attached bacteria. KEY POINTS: • A novel bacterium (JXJCY 53 T) was isolated from the cyanosphere of Microcystis sp. FACHB-905 (MF-905) • JXJCY 53 T modulated the growth and microcystin production of MF-905 • MF-905 could control the attached bacteria by specific chemicals other than microcystins (MCs).

Sphingomonas arenae sp. nov., isolated from desert soil.

Two bacterial strains, designated as SYSU D00720T and SYSU D00722, were isolated from a desert sandy soil sample collected from Gurbantunggut Desert in Xinjiang, north-west China. Cells were Gram-stain-negative, aerobic, non-motile, rod-shaped, oxidase-positive and catalase-negative. Colonies were circular, opaque, convex, smooth, orange on Reasoner's 2A (R2A) agar. The isolates were found to grow at 4-45 °C (optimum, 28-30 °C), at pH 6.0-7.0 (optimum, 7.0) and with 0-1.5 % (w/v) NaCl (optimum, 0%). Growth was observed on R2A agar, Luria-Bertani agar and nutrient agar, but not on trypticase soy agar. The polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, sphingoglycolipid, two unidentified aminolipids, one unidentified glycolipid, one unidentified aminoglycolipid, one unidentified aminophospholipid, one unidentified phospholipid and two unidentified lipids. The main fatty acids (>10%) were C17 : 1 ω6c, summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c) and C16 : 0. The major respiratory quinone was ubiquinone-10 and the major polyamine was sym-homospermidine. The genomic DNA G+C content was 66.0 mol%. Strains SYSU D00720T and SYSU D00722 were nearly identical with a 16S rRNA gene sequence similarity of 99.6 %, and 100.0 % average nucleotide identity (ANI), average amino acid identity (AAI) and digital DNA-DNA hybridization (dDDH) values. Phylogenetic analyses clearly demonstrated that these two strains belonged to the same species of the genus Sphingomonas, and had highest sequence similarity to Sphingomonas lutea KCTC 23642T (97.3 %). The ANI, AAI and dDDH values of strains SYSU D00720T and SYSU D00722 to S. lutea KCTC 23642T were both 73.2, 69.9 and 19.2 %, respectively. Based on phylogenetic, phenotypic and chemotaxonomic distinctiveness, strains SYSU D00720T and SYSU D00722 represent a novel species of the genus Sphingomonas, for which the name Sphingomonas arenae sp. nov. is proposed. The type strain is SYSU D00720T (=MCCC 1K05154T=NBRC 115061T).

Induction of Apoptosis in Human Lung Epithelial Cell by Sphingomonas sp. Shah, a Recently Identified Cell Culture Contaminant.

Sphingomonas sp. Shah is a bacterium that was first isolated from mammalian cell cultures. According to ribotyping data it is very much homologous to the clinically important pathogen Sphingomonas paucimobilis, which has generated pseudo-outbreaks. Using a tissue culture system, Sphingomonas sp. Shah was discovered to induce apoptosis in human lung epithelial carcinoma. Apoptosis of infected cells was determined by numerous criteria including (1) visual alterations in cellular morphology, (2) initiation of nuclear marginalization and chromatin compaction condensation, (3) the attendance of a high percentage of cells with subG1 DNA content, and (4) caspase-3 activation. In the current study we demonstrate the induction of apoptosis in mammalian lung epithelial cells upon infection with Sphingomonas sp. Shah and provide insight into the molecular processes triggering apoptosis.

Sphingomonas horti sp. nov., a novel bacterial species isolated from soil of a tomato garden.

A novel bacterial strain, designated MAH-20T, was isolated from a soil sample of a tomato garden. Cells of strain MAH-20T were Gram-stain negative, aerobic, motile, and rod-shaped. The colonies were light brown colored, smooth, spherical, and 0.2-0.7 mm in diameter when grown on Luria-Bertani agar for 2 days. Strain MAH-20T grows at 15-40 °C (optimum growth temperature 30-32 °C), at pH 5.0-10.0 (optimum growth pH 7.0) and at 0-2.0% NaCl. The strain showed positive activity for both oxidase and catalase tests. Cells were able to hydrolyze starch, DNA, urea, gelatin, L-arginine, and Tween 20. According to the 16S rRNA gene sequence similarity, the strain MAH-20T was identified as a new member of the genus Sphingomonas and had the close sequence similarity with Sphingomonas changbaiensis V2M44T (98.9%) and Sphingomonas tabacisoli X1-8T (98.1%). The genomic ANI value between strain MAH-20T and S. changbaiensis NBRC 104936T was 84.4%. The novel strain MAH-20T has a draft genome size of 3,350,026 bp (25 contigs), annotated with 3210 protein-coding genes, 46 tRNA, and 3 rRNA genes. The genomic DNA G + C content of isolate was 67.3 mol%, the predominant quinone was ubiquinone 10 and the major fatty acids were C16:0, C17:1 ω6c and summed feature 8 (comprising C18:1 ω7c and/or C18:1 ω6c). On the basis of DNA-DNA hybridization results, phenotypic, genotypic, and chemotaxonomic data, the isolated strain MAH-20T represents a novel species, for which the name Sphingomonas horti sp. nov. is proposed, with MAH-20T as the type strain (= KACC 19746T = CGMCC1.13658T).

Sphingomonas aliaeris sp. nov., a new species isolated from pork steak packed under modified atmosphere.

Species belonging to the genus Sphingomonas have been isolated from environments such as soil, water and plant tissues. Many strains are known for their capability of degrading aromatic molecules and producing extracellular polymers. A Gram-stain-negative, strictly aerobic, motile, red-pigmented, oxidase-negative, catalase-positive, rod-shaped strain, designated DH-S5T, has been isolated from pork steak packed under CO2-enriched modified atmosphere. Cell diameters were 1.5×0.9 µm. Growth optima were at 30 °C and at pH 6.0. Phylogenetic analyses based on both complete 16S rRNA gene sequence and whole-genome sequence data revealed that strain DH-S5T belongs to the genus Sphingomonas, being closely related to Sphingomonas alpina DSM 22537T (97.4 % gene sequence similarity), followed by Sphingomonas qilianensis X1T (97.4 %) and Sphingomonas hylomeconis GZJT-2T (97.3 %). The DNA G+C content was 64.4 mol%. The digital DNA-DNA hybridization value between the isolate strain and S. alpina DSM 22537T was 21.0 % with an average nucleotide identity value of 77.03 %. Strain DH-S5T contained Q-10 as the ubiquinone and major fatty acids were C18 : 1 cis 11 (39.3 %) and C16 : 1 cis 9 (12.5 %), as well as C16 : 0 (12.1 %) and C14 : 0 2-OH (11.4 %). As for polar lipids, phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, dimethylphosphatidylethanolamine and sphingoglycolipid could be detected, alongside traces of monomethylphosphatidylethanolamine. Based on its phenotypic, chemotaxonomic and phylogenetic characteristics, strain DH-S5T (=DSM 110829T=LMG 31606T) is classified as a representative of the genus Sphingomonas, for which the name Sphingomonas aliaeris sp. nov. is proposed.

Sphingomonas parva sp. nov., isolated from soil in Jeju Island.

A Gram staining-negative, yellow-colored, rod-shaped, non-motile and aerobic, designated strain 17J27-24T was isolated from a soil sample in Korea. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain 17J27-24T was related to the members of the family Sphingomonadaceae and formed a distinct monophyletic cluster within the genus Sphingomonas with Sphingomonas deserti (98.3% 16S rRNA gene sequence similarity). Growth was observed at 30 °C (optimum), at pH 7.0 (optimum), and in the absence of NaCl (%). The predominant cellular fatty acids were summed feature 8 (18:1 ω7c and/or 18:1 ω6c) and C17:1 ω6c. The major respiratory quinone was Q10. The polar lipids profile comprised of diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), and sphingoglycolipid (SGL). The DNA G + C content was 77.8 mol%. The average nucleotide identity (ANI) and digital DNA-DNA hybridisation (dDDH) values between 17J27-24T and its phylogenetically closest Sphingomonas deserti (KCTC 62411T) were below the established cut-off < 94% (ANI) and < 70% (dDDH) for species delineation. Moreover, the results of the polyphasic approach confirmed that strain 17J27-24T represents a novel species of the genus Sphingomonas within the family Sphingomonadaceae, for which the name Sphingomonas parva sp. nov. is proposed. The type strain of this species is 17J27-24T (= KCTC 62208T = JCM 3896T). An emended description of the species Sphingomonas parva is provided.

Reclassification of Sphingomonas aeria as a later heterotypic synonym of Sphingomonas carotinifaciens based on whole-genome sequence analysis.

The 16S rRNA gene sequences of Sphingomonas carotinifaciens L9-754T and Sphingomonas aeria B093034T possess 99.71 % sequence similarity. Further studies were undertaken to clarify the taxonomic assignments of these species. Whole-genome comparisons showed that S. aeria B093034Tand S. carotinifaciens L9-754T shared 96.9 % average nucleotide identity, 98.4 % average amino acid identity and 76.1 % digital DNA-DNA hybridization values. These values exceeded or approached the recommended species delineation threshold values. Furthermore, a phylogenetic tree based on 41 of the most conserved genes provided additional evidence that S. aeria B093034T and S. carotinifaciens L9-754T are very closely related. Based on this evidence we propose the reclassification of S. aeria Xue et al. 2018 as a later heterotypic synonym of S. carotinifaciens Madhaiyan et al. 2017.

Sphingomonas solaris sp. nov., isolated from a solar panel in Boston, Massachusetts.

Solar panel surfaces, although subjected to a range of extreme environmental conditions, are inhabited by a diverse microbial community adapted to solar radiation, desiccation and temperature fluctuations. This is the first time a new bacterial species has been isolated from this environment. Strain R4DWNT belongs to the genus Sphingomonas and was isolated from a solar panel surface in Boston, MA, USA. Strain R4DWNT is a Gram-negative, non-motile and rod-shaped bacteria that tested positive for oxidase and catalase and forms round-shaped, shiny and orange-coloured colonies. It is mesophilic, neutrophilic and non-halophilic, and presents a more stenotrophic metabolism than its closest neighbours. The major fatty acids in this strain are C18:1ω7c/C18:1ω6c, C16:1ω7c/C16:1ω6c, C14:0 2OH and C16:0. Comparison of 16S rRNA gene sequences revealed that the closest type strains to R4DWNT are Sphingomonas fennica, Sphingomonas formosensis, Sphingomonas prati, Sphingomonas montana and Sphingomonas oleivorans with 96.3, 96.1, 96.0, 95.9 and 95.7 % pairwise similarity, respectively. The genomic G+C content of R4DWNT is 67.9 mol%. Based on these characteristics, strain R4DWNT represents a novel species of the genus Sphingomonas for which the name Sphingomonas solaris sp. nov. is proposed with the type strain R4DWNT (=CECT 9811T=LMG 31344T).

Sphingomonas changnyeongensis sp. nov. isolated from the Hapcheon-Changnyeong barrage area in the Nakdong river.

The novel bacterial strain C33T was isolated from a freshwater sample collected from the Hapcheon-Changnyeong barrage. The Gram-negative, motile, yellow-pigmented strain C33T was characterized as a rod-shaped and strictly aerobic bacterium. A 16S-rRNA phylogenetic analysis revealed that this strain was most closely related to Sphingomonas changbaiensis V2M44T, Sphingomonas tabacisoli X1-8T, and Sphingomonas flavalba ZLT-5T with 97.1, 97.0, and 95.0 % 16S-rRNA sequence similarities, respectively. The genomic DNA GC content of strain C33T was estimated at 65.0 mol%. The average nucleotide identity of strain C33T relative to S. changbaiensis V2M44T and S. flavalba ZLT-5T was found to be 77.0 and 75.6%, with average amino-acid identities of 69.9, and 66.7%, and the digital DNA-DNA hybridization values of 21.3 and 17.7 %, respectively. The cells grew at 19-37 °C and pH 6-9 with 0-0.5 % (w/v) NaCl (optimum: 28 °C, pH 6.5, and 0 % NaCl). The major component identified in the polyamine pattern was sym-homospermidine, and the main ubiquinone was Q-10. The predominant polar lipids characterized were diphophatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidyldimethylethanolamine, and sphingoglycolipid. Iso-C15 : 0, C15 : 0 anteiso, and summed feature 3 (C16 : 1 ω6c and/or C16 : 1 ω7c) were found to be the primary cellular fatty acids in strain C33T. Based on these genotypic and phenotypic characteristics, strain C33T was classified as a novel species of the genus Sphingomonas; and the name Sphingomonas changnyeongensis sp. nov. is proposed (=KACC 21511T=JCM 33880T).

Sphingomonas chungangi sp. nov., a bacterium isolated from garden soil sample.

A novel bacterial strain, designated MAH-6T, was isolated from a garden soil sample. Cells were Gram-stain-negative, aerobic, non-motile and rod-shaped. The colonies were light yellow, smooth, circular and 0.6-1.2 mm in diameter when grown on nutrient agar for 3 days. Strain MAH-6T grew at 15-35 °C, at pH 5.0-7.0 and with 0-0.5 % NaCl. Cell growth occurred on nutrient agar and Reasoner's 2A (R2A) agar. The strain was positive for both catalase and oxidase tests. Cells were able to hydrolyse starch, aesculin, Tween 20 and Tween 80. According to 16S rRNA gene sequence comparisons, the isolate was identified as a member of the genus Sphingomonas and was most closely related to Sphingomonas polyaromaticivorans B2-7T (98.2 % sequence similarity), Sphingomonas oligoaromativorans SY-6T (96.9 %) and Sphingomonas morindae NBD5T (96.6 %). The novel strain MAH-6T has a draft genome size of 4 370 740 bp (28 contigs), annotated with 4199 protein-coding genes, 46 tRNA and three rRNA genes. The genomic DNA G+C content of the strain was determined to be 66.2 mol% and the predominant isoprenoid quinone is Q-10. The major fatty acids were identified as summed feature 8 (comprising C18 : 1 ω7c and/or C18 : 1 ω6c), C14 : 0 2OH and C16 : 0. The main polar lipids were phosphatidylcholine, sphingoglycolipid, phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. Based on the results of phenotypic, genotypic, chemotaxonomic and DNA-DNA hybridization studies, strain MAH-6T represents a novel species, for which the name Sphingomonas chungangi sp. nov. is proposed, with MAH-6T as the type strain (=KACC 19292T=CGMCC1.13654T).

Sphingomonas segetis sp. nov., isolated from spinach farming field soil.

A Gram-stain-negative bacterium, designated strain YJ09T, was isolated from spinach farming field soil at Shinan in the Republic of Korea. Cells of strain YJ09T were found to be strictly aerobic, non-motile, non-spore-forming creamy-yellow rods which can grow at 20-37 °C (optimum, 30 °C), at pH 6.0-9.0 (optimum, pH 7.0-8.0) and at salinities of 0-0.5 % (w/v) NaCl (optimum, 0 % NaCl). The 16S rRNA gene sequence analysis showed that strain YJ09T belongs to the genus Sphingomonas with high sequence similarities to Sphingomonas parvus GP20-2 T (98.0 %), Sphingomonas agri HKS-06T (97.7 %) and Sphingomonas lutea JS5T (97.4 %). The results of phylogenetic analysis indicated that strain YJ09T formed a distinct phyletic line in the genus Sphingomonas and the results of DNA-DNA relatedness studies demonstrated that strain YJ09T could be separated from its closest relatives in the genus Sphingomonas. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, unidentified glycolipids, an unidentified phospholipid and sphingoglycolipid. The predominant ubiquinone and polyamine components were Q-10 and spermidine, respectively. The major fatty acids were C18:1 ω7c, C16  : 0 and C16:1 ω7c and/or iso-C15 : 0 2-OH. The DNA G+C content of this novel isolate was 65.9 mol%. On the basis of phenotypic, chemotaxonomic properties and phylogenetic analyses in this study, strain YJ09T is considered to represent a novel species in the genus Sphingomonas, for which the name Sphingomonas segetis sp. nov. is proposed. The type strain is YJ09T (=KACC 19551T=NBRC 113247T).

Sphingomonas lacunae sp. nov., isolated from a freshwater pond.

A novel bacterial strain, designated CSW-10T, isolated from a freshwater pond in Taiwan, was characterized using a polyphasic taxonomic approach. Cells were Gram-stain-negative, aerobic, non-motile, rod-shaped and formed yellow-coloured colonies. Optimal growth occurred at 30 °C, pH 7, and in the absence of NaCl. Phylogenetic analyses based on 16S rRNA gene sequences and coding sequences of 92 protein clusters indicated that strain CSW-10T formed a phylogenetic lineage in the genus Sphingomonas. The 16S rRNA gene sequence similarity indicated that strain CSW-10T was most closely related to Sphingomonas fonticola TNR-2T (97.6%). Strain CSW-10T showed 69.8-70.7% average nucleotide identity and 19.0-23.0% digital DNA-DNA hybridization identity with the strains of other related Sphingomonas species. The major fatty acids of strain CSW-10T were summed feature 8 (C18:1 ω7c and/or C18:1 ω6c) and C17:1 ω6c. The polar lipid profile consisted of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidyldimethylethanolamine, phosphatidylcholine, one uncharacterized sphingoglycolipid, five uncharacterized aminophospholipids, one uncharacterized phospholipid and one uncharacterized lipid. The predominant polyamines were homospermidine and spermidine. The major isoprenoid quinone was Q-10. Genomic DNA G+C content of strain CSW-10T was 62.0 mol%. On the basis of phenotypic and genotypic properties and phylogenetic inference, strain CSW-10T should represent a novel species of the genus Sphingomonas, for which the name Sphingomonas lacunae sp. nov. is proposed. The type strain is CSW-10T (=BCRC 81190T =LMG 31340T).

Sphingomonas corticis sp. nov., and Sphingobacterium corticibacterium sp. nov., from bark canker.

Two Gram-stain-negative, aerobic, non-motile bacterial strains, 36D10-4-7T and 30C10-4-7T, were isolated from bark canker tissue of Populus × euramericana, respectively. 16S rRNA gene sequence analysis revealed that strain 36D10-4-7T shows 98.0 % sequence similarity to Sphingomonas adhaesiva DSM 7418T, and strain 30C10-4-7T shows highest sequence similarity to Sphingobacterium arenae H-12T (95.6 %). Average nucleotide identity analysis indicates that strain 36D10-4-7T is a novel member different from recognized species in the genus Sphingomonas. The main fatty acids and respiratory quinone detected in strain 36D10-4-7T are C18 : 1 ω7c and/or C18 : 1 ω6c and Q-10, respectively. The polar lipids are diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol, aminolipid, phosphatidylethanolamine, sphingoglycolipid, two uncharacterized phospholipids and two uncharacterized lipids. For strain 30C10-4-7T, the major fatty acids and menaquinone are iso-C15 : 0, C16 : 1 ω7c and/or C16 : 1 ω6c and iso-C17 : 0 3-OH and MK-7, respectively. The polar lipid profile includes phosphatidylethanolamine, phospholipids, two aminophospholipids and six unidentified lipids. Based on phenotypic and genotypic characteristics, these two strains represent two novel species within the genera Sphingomonas and Sphingobacterium. The name Sphingomonas corticis sp. nov. (type strain 36D10-4-7T=CFCC 13112T=KCTC 52799T) and Sphingobacterium corticibacterium sp. nov. (type strain 30C10-4-7T=CFCC 13069T=KCTC 52797T) are proposed.

Sphingomonas montanisoli sp. nov., isolated from mountain soil.

A soil bacterium, designated ZX9611T, was isolated from Taihang Mountain in Henan province, PR China. The strain was Gram-stain-negative and strictly aerobic. The cells were motile, rod-shaped and formed light pink-colored colonies. The 16S rRNA gene sequence of ZX9611T shared the highest similarities with those of Sphingomonas crocodyli CCP-7T (97.0%), Sphingomonas jatrophae S5-249T (96.6%) and Sphingomonas starnbergensis 382T (95.9%). Phylogenetic analyses based on 16S rRNA gene sequences demonstrated that ZX9611T clustered with S. crocodyli CCP-7T, S. jatrophae S5-249T and S. starnbergensis 382T. The average nucleotide identity (ANI) values between ZX9611T and two type strains (S. crocodyli BCRC 81096T and S. jatrophae DSM 27345T) were 88.3 and 68.6% respectively. ZX9611T exhibited genome-sequence-based digital DNA-DNA hybridization (dDDH) values of 53.3 % and 15.3 %, compared with S. crocodyli BCRC 81096T and S. jatrophae DSM 27345T, respectively. ZX9611T had a genome size of 4.12 Mb and an average DNA G+C content of 64.8 %. ZX9611T had major fatty acids (>5 %) including summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c), C14 : 0 2-OH, C16 : 0 and summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), and the major polyamine was sym-homospermidine. The only respiratory quinone was ubiquinone-10. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine and sphingoglycolipid. On the basis of phenotypic, chemotaxonomic and phylogenetic characteristics, strain ZX9611T represents a novel species of genus Sphingomonas, for which the name Sphingomonas montanisoli sp. nov. is proposed. The type strain is ZX9611T (=KCTC 72622T=CCTCC AB 2019350T).

Sphingomonas profundi sp. nov., isolated from deep-sea sediment of the Mariana Trench.

A Gram-stain-negative, short rod-shaped, yellow bacterium (strain LMO-1T) was isolated from deep-sea sediment of the Mariana Trench, Challenger Deep. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain LMO-1T belonged to genus Sphingomonas, with the highest sequence similarity to Sphingomonas formosensis CC-Nfb-2T (96.3 %), followed by Sphingomonas prati W18RDT (96.1 %), Sphingomonas arantia 6PT (96.0 %) and Sphingomonas montana W16RDT (95.9 %). The predominant polar lipids were phosphatidylethanolamine, sphingoglycolipid, phosphatidylglycerol and phosphatidylcholine. The main cellular fatty acids were summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c), C16 : 0 and C14 : 0 2-OH. The major polyamine was sym-homospermidine and the predominant isoprenoid quinone was ubiquinone-10. The genome DNA G+C content of strain LMO-1T was 69.2 mol%. The average nucleotide identity and DNA-DNA hybridization values between strain LMO-1T and CC-Nfb-2T were 75.9 and 20.5 %, respectively. Based on these data, LMO-1T should be classified as representing a novel species of the genus Sphingomonas, for which the name Sphingomonas profundi sp. nov. is proposed. The type strain is LMO-1T (=MCCC 1K04066T=JCM 33666T).

Sphingomonas suaedae sp. nov., a chitin-degrading strain isolated from rhizosphere soil of Suaeda salsa.

A Gram-stain-negative, aerobic, chitin-degrading, motile bacterial strain with a single polar flagellum, designated XS-10T, was isolated from saline soil sampled from the rhizosphere of Suaeda salsa, Tumd Right Banner, Inner Mongolia, PR China. Strain XS-10T grew at 10-40 °C (optimum, 35 °C), pH 5.0-9.0 (optimum, pH 8.0) and 0-12.5% NaCl (optimum 2.0 %). The phylogenetic analysis based on both the 16S rRNA gene and the phylogenomic tree revealed that strain XS-10T formed a clade with Sphingomonas turrisvirgatae MCT13T and Sphingomonas koreensis JSS-26T, sharing 98.4 and 97.5 % 16S rRNA gene similarities to S. koreensis JSS-26T and S. turrisvirgatae MCT13T, respectively. Spermidine and Q-10 were the major polyamine and the major respiratory quinone, respectively. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, sphingoglycolipid, two unidentified lipids and an unidentified aminophospholipid. The major fatty acids were summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c), C16 : 0 and C17 : 1 ω6c. The genome of strain XS-10T consisted of a 4 154 291 bp chromosome with a DNA G+C content of 65.5 mol%. The average nucleotide identity, average amino acid identity and digital DNA-DNA hybridization values of strain XS-10T with S. turrisvirgatae MCT13T and S. koreensis JSS-26T were 77.8 and 78.6 %, 75.9 and 76.3 %, and 22.0 and 22.9 %, respectively. Based on the phylogenetic, phenotypic, and genotypic characteristics, strain XS-10T is considered to represent a novel species of the genus Sphingomonas, for which the name Sphingomonas suaedae sp. nov. is proposed. The type strain is XS-10T (=CGMCC 1.17078T=JCM 33850T).

Sphingomonas edaphi sp. nov., a novel species isolated from beach soil in the Republic of Korea.

A yellow-coloured, Gram-negative, motile, strictly aerobic bacterial strain, designated strain DAC4T, was isolated from a soil sample collected at Ahnmok Beach (Busan, Republic of Korea). The cells of strain DAC4T were rod-shaped and the colonies that formed were round and convex. The results of phylogenetic analysis based on the 16S rRNA gene sequence of strain DAC4T revealed that the bacterium belongs to the genus Sphingomonas, family Sphingomonadaceae, and that it was most closely related to Sphingomonas jaspsi DSM 18422T (98.01 %), Sphingomonas rhizophila KACC 19189T (97.76 %), Sphingomonas mesophila KCTC 62179T(97.30 %), Sphingomonas sedimincola KCTC 12629T (97.16 %) and Sphingomonas oryziterrae KCTC 22476T (97.05 %). The major respiratory quinone was Q-10, and the major cellular fatty acids were summed feature 8 (C18  :  1ω7c) and summed feature 3 (C16  :  1ω7c/C16  :  1ω6c). The whole genome DNA G+C content of strain DAC4T was 62.16 mol%. Phosphatidylethanolamine, diphosphatidylglycerol, sphingoglycolipids, phosphatidylglycerol, phosphatidylcholine, four undefined glycolipids and an undefined lipid were detected in strain DAC4T, and the strain had sym-homospermidine as a major polyamine. The in silico DNA-DNA hybridization and average nucleotide identity values between strain DAC4T and the closely related taxa S. jaspsi and S. mesophila were 75.5/23.5 % and 73.5 /18.5%, respectively. The fluorimetric DNA-DNA hybridization results showed that strain DAC4T and S. rhizophila, S. sediminicola and S. oryziterrae have 37.1, 35.2 and 32.2 % DNA similarity, respectively. Based on phylogenetic, phenotypic and chemotaxonomic distinctiveness, strain DAC4T (=KCTC 62107T=JCM 32377T) is classified as a novel species of the genus Sphingomonas, for which the name Sphingomonas edaphi sp. nov. is proposed.

Sphingomonas populi sp. nov., isolated from bark of Populus × euramericana.

One Gram-stain-negative, aerobic, motile bacterial strain, 3-7T, was isolated from symptomatic canker bark tissue of Populus × euramericana. 16S rRNA gene sequence data revealed that the novel isolate shared highest similarity with Sphingomonas panacis DCY99T (98.8 %), and <96.5 % sequence similarity with all other species with validly published names. Growth occurred between 15 and 37 °C and at pH 6.0-9.0, and optimal growth occurred at 30 °C and pH 7.0-8.0. Nitrogen was produced from nitrates. The strain was positive for acetoin production and activity of catalase, oxidase, ß-galactosidase, arginine dihydrolase and ß-glucosidase. The major fatty acids were C16 : 0, C18 : 1ω7c and/or C18 : 1ω6c. The polar lipids of the novel isolate included diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, sphingoglycolipid, glycolipid, two uncharacterized phospholipids and two uncharacterized lipids. The respiratory quinones detected in isolate 3-7T were Q-10 (96.9 %) and Q-9 (3.1 %). The DNA G+C content was 65.1 mol%. Based on phenotypic and genotypic characteristics, the isolate represents a novel species within the genus Sphingomonas, for which the name Sphingomonas populi is proposed. The type strain is 3-7T (=CFCC 11561T=LMG 30138T).

Sphingomonas hominis sp. nov., isolated from hair of a 21-year-old girl.

A Gram-stain-negative, aerobic, motile strain, HHU CXWT, was isolated from hair of a healthy 21-year-old female student of Hohai University, Nanjing, China. The 16S rRNA gene sequence analysis indicated that HHU CXWT represents a member of the genus Sphingomonas with the highest sequence similarity (97.6%) to the type strain S. aquatilis JSS7T. HHU CXWT grew at 4-35 °C and pH 6-8, with optimum growth at 28 °C and pH 7. Tolerance to NaCl was up to 2% (w/v) with optimum growth in 0.5-1.0% NaCl. The major fatty acids were C16:0, C17:1ω6c, C18:1ω7c11-methyl, summed feature 3 (C16:1ω7c and/or C16:1ω6c), and summed feature 8 (C18:1ω7c and/or C18:1ω6c). The predominant isoprenoid quinone was ubiquinone-10. The polar lipids were diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), sphingoglycolipid (SGL), phosphatidylinositol mannosides (PIM), and an unidentified glycolipid (GL). The DNA G + C content was 67.1%. The average nucleotide identity (ANI) values and digital DNA-DNA hybridization (dDDH) between HHU CXWT and closely related members of the genus Sphingomonas were all below the cut-off level (95-96% and 70%, respectively) for species delineation. On the basis of the phenotypic, phylogenetic and chemotaxonomic characterizations, HHU CXWT represents a novel species of the genus Sphingomonas, for which the name Sphingomonas hominis sp. nov. is proposed. The type strain is HHU CXWT (= KCTC 72946T = CGMCC 1.17504T = MCCC 1K04223T).