Phylogenomic reappraisal of the family Rhizobiaceae at the genus and species levels, including the description of Ectorhizobium quercum gen. nov., sp. nov

The family Rhizobiaceae contains 19 validly described genera including the rhizobia groups, many of which are important nitrogen-fixing bacteria. Early classification of Rhizobiaceae relied heavily on the poorly resolved 16S rRNA genes and resulted in several taxonomic conflicts. Although several recent studies illustrated the taxonomic status of many members in the family Rhizobiaceae, several para- and polyphyletic genera still needed to be elucidated. The rapidly increasing number of genomes in Rhizobiaceae has allowed for a revision of the taxonomic identities of members in Rhizobiaceae. In this study, we performed analyses of genome-based phylogeny and phylogenomic metrics to review the relationships of 155-type strains within the family Rhizobiaceae. The UBCG and concatenated protein phylogenetic trees, constructed based on 92 core genes and concatenated alignment of 170 single-copy orthologous proteins, demonstrated that the taxonomic inconsistencies should be assigned to eight novel genera, and 22 species should be recombined. All these reclassifications were also confirmed by pairwise cpAAI values, which separated genera within the family Rhizobiaceae with a demarcation threshold of ~86%. In addition, along with the phenotypic and chemotaxonomic analyses, a novel strain BDR2-2T belonging to a novel genus of the family Rhizobiaceae was also confirmed, for which the name Ectorhizobium quercum gen. nov., sp. nov. was proposed. The type strain is BDR2-2T (=CFCC 16492T = LMG 31717T).

Reclassification of 11 Members of the Family Rhodobacteraceae at Genus and Species Levels and Proposal of Pseudogemmobacter hezensis sp. nov

A novel Gram-stain-negative, aerobic, motile bacterial strain, D13-10-4-6^T, was isolated from the bark sample of Populus × euramericana. The strain could grow at 15-35°C, at pH 6-10 and in 0-4% (w/v) NaCl, and the strain tested positive for oxidase and catalase activities. The main polar lipids were phosphatidylmonomethylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine. The main respiratory quinone was Q-10, and the predominant fatty acid was C_18:1 ω7c. The phylogenetic analyses showed that the strain belonged to the genus Pseudogemmobacter of the family Rhodobacteraceae. The family Rhodobacteraceae is an ecologically diverse group that includes bacteria from aquatic to terrestrial ecosystems. As a consequence, the classification of the family Rhodobacteraceae is difficult, not least when the early taxonomy work relied heavily on 16S rRNA gene analysis. Recently, the taxonomic status of many members of the family has been revised based on the genome analysis; however, there are still some classification conflicts due to the lack of genome sequences and parallel publication time. In this study, phylogenetic trees based on 16S rRNA gene, gyrB gene, and 120 concatenated proteins, the average amino acid identity (AAI) and percentage of conserved proteins (POCP) have been used for the analysis of strain D13-10-4-6^T and other members of 15 genera within the family to further clarify their taxonomic relationships. For the data of phylogeny, AAI, and POCP, the taxonomic proposals are (1) reclassification of Rhodobacter tardus as the type species of a novel genus, Stagnihabitans gen. nov., as Stagnihabitans tardus comb. nov.; (2) reclassification of Tabrizicola alkalilacus, Tabrizicola sediminis, Tabrizicola algicola into a novel genus, Pseudotabrizicola gen. nov., as Pseudotabrizicola alkalilacus comb. nov., Pseudotabrizicola sediminis comb. nov., Pseudotabrizicola algicola comb. nov.; (3) reclassification of Rhodobacter sediminicola into the genus Cereibacter as Cereibacter sediminicola comb. nov.; (4) reclassification of Rhodobacter flagellatus, Rhodobacter thermarum, and Xinfangfangia soli into the genus Tabrizicola as Tabrizicola flagellatus comb. nov., Tabrizicola thermarum comb. Nov., and Tabrizicola soli comb. nov.; (5) reclassification of Xinfangfangia humi into the genus Pseudogemmobacter as Pseudogemmobacter humicola comb. nov.; (6) classification of strain D13-10-4-6^T as a novel species of the genus Pseudogemmobacter, for which the name P. hezensis sp. nov. is proposed, the type strain is D13-10-4-6^T (= CFCC 12033^T = KCTC 82215^T).

Pseudomonas quercus sp. nov, associated with leaf spot disease of Quercus mongolica

Two Gram-negative, aerobic, motile bacteria strains were isolated from leaf spot disease of Quercus mongolica. Strain hsmgli-8^T has 99.86 % 16S rRNA gene sequence similarity to LY10J, and the highest 16S rRNA gene sequence similarity to Pseudomonas cerasi 58^T (97.2 %), then Pseudomonas ficuserectae JCM 2400^T (97.18 %), Pseudomonas meliae CFBP 3225^T, Pseudomonas tremae CFBP 6111^T and Pseudomonas congelans DSM 14939^T (all 97.12 %), and less than 97.1 % similarity to other recognized species. In phylogenetic trees based on 16S rRNA gene and multilocus sequence data, the two novel strains form a separate branch, indicating that they do not belong to any Pseudomonas group and subgroup, and should belong to a novel species within the genus Pseudomonas. This assertion is also supported by the results of genome average nucleotide identity analysis. The major fatty acids are C_16 : 0, C_18 : 1 ω7c and/or C_18 : 1 ω6c, C_16 : 1 ω7c and/or C_16 : 1  ω6c. Polar lipids include phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, aminolipid and seven uncharacterized phospholipids. The predominant respiratory quinone is Q-9. The DNA G+C content is 59.45-59.50 mol%. Based on these data, we propose that the two novel strains should be assigned as a novel species within the genus Pseudomonas. We propose that the novel strains be named Pseudomonas quercus sp. nov. The type strain is hsmgli-8^T (=CFCC 15739^T=LMG 31544^T).

Affinibrenneria salicis gen. nov. sp. nov. isolated from Salix matsudana bark canker

L3-3HA^T, a Gram-negative-staining, facultatively anaerobic, motile bacterial strain, was isolated from the symptomatic bark of Salix matsudana canker in China. 16S rRNA gene analysis revealed that the novel strain shares the highest sequence similarity with Brenneria goodwinii FRB141^T (95.5%). In phylogenetic trees based on four housekeeping genes (gyrB, rpoB, atpD, and infB) and the 16S rRNA gene sequence, the novel strain formed a separate branch from the five genera of the family Pectobacteriaceae (Lonsdalea, Brenneria, Dickeya, Pectobacterium, and Sodalis), suggesting that the novel strain should belong to a novel species of a novel genus within the family Pectobacteriaceae. The result was also supported by phylogenomics, amino acid identity and average nucleotide identity. The major fatty acids were C_14:0, C_16:0, C_17:0 cyclo, and C_19:0 cyclo ɷ8c. Genome analysis showed that the novel strain has a large genome (5.89 Mb) with 5,052 coding genes, including 181 virulence genes by searching the pathogen-host interactions database (PHI-base), indicating that the novel strain is a potential pathogen of plants and animals. Based on phenotypic and genotypic characteristics, the L3-3HA^T strain represents a novel species of a novel genus in the Pectobacteriaceae family, for which the name Affinibrenneria salicis gen nov. sp. nov. is proposed. The strain type is L3-3HA^T (= CFCC 15588^T = LMG 31209^T).

Sphingobacterium chungjuense sp. nov., isolated from a freshwater lake

A Gram-stain-negative, rod-shaped, aerobic, non-flagellated, chemoheterotrophic bacterium, designated strain IMCC25678^T, was isolated from an artificial freshwater reservoir, Chungju Lake, in the Republic of Korea. The 16S rRNA gene sequence analysis indicated that strain IMCC25678^T belongs to the genus Sphingobacterium with ≤98.7 % sequence similarities to Sphingobacterium species. Whole genome sequencing of strain IMCC25678^T revealed a 3.9 Mbp genome size with a DNA G+C content of 42.2 mol%. The IMCC25678^T genome shared ≤89.7 % average nucleotide identity and ≤21.4 % digital DNA-DNA hybridization values with closely related species of the genus Sphingobacterium, indicating that the strain represents a novel species. Summed feature 3 (C_16 : 1  ω6c and/or C_16 : 1  ω7c), iso-C_15 : 0 and iso-C_17 : 0 3-OH were found to be the predominant cellular fatty acid constituents in the strain. The major respiratory quinone was MK-7. The major polar lipids were phosphatidylethanolamine, one unidentified phosphoglycolipid, one unidentified sphingolipid and three unidentified polar lipids. Based on the phylogenetic and phenotypic characteristics, strain IMCC25678^T was considered to represent a novel species within the genus Sphingobacterium, for which the name Sphingobacterium chungjuense sp. nov. is proposed. The type strain is IMCC25678^T (=KACC 19485^T=NBRC 113130^T).

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

Two Gram-stain-negative, aerobic, non-motile bacterial strains, 36D10-4-7^T and 30C10-4-7^T, were isolated from bark canker tissue of Populus × euramericana, respectively. 16S rRNA gene sequence analysis revealed that strain 36D10-4-7^T shows 98.0 % sequence similarity to Sphingomonas adhaesiva DSM 7418^T, and strain 30C10-4-7^T shows highest sequence similarity to Sphingobacterium arenae H-12^T (95.6 %). Average nucleotide identity analysis indicates that strain 36D10-4-7^T is a novel member different from recognized species in the genus Sphingomonas. The main fatty acids and respiratory quinone detected in strain 36D10-4-7^T are C_18 : 1  ω7c and/or C_18 : 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 30C10-4-7^T, the major fatty acids and menaquinone are iso-C_15 : 0, C_16 : 1  ω7c and/or C_16 : 1  ω6c and iso-C_17 : 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 36D10-4-7^T=CFCC 13112^T=KCTC 52799^T) and Sphingobacterium corticibacterium sp. nov. (type strain 30C10-4-7^T=CFCC 13069^T=KCTC 52797^T) are proposed.

Stenotrophomonas cyclobalanopsidis sp. nov., isolated from the leaf spot disease of Cyclobalanopsis patelliformis

A Gram-negative, facultatively anaerobic, motile bacterial strain, TPQG1-4^T, was isolated from the leaf of Cyclobalanopsis patelliformis with spot disease. The isolate was investigated using the polyphasic taxonomic approach. 16S rRNA gene sequencing and analyzing revealed that the novel strain shares the highest sequence similarity with Stenotrophomonas lactitubi M15^T (99.6%), Stenotrophomonas indicatrix WS40^T (99.4%), Stenotrophomonas maltophilia IAM 12423^T (99.2%) and Stenotrophomonas pavanii LMG 25348^T (99.0%). In phylogenetic trees based on 16S rRNA gene sequences, the novel strain branched independently from other species of Stenotrophomonas. Average nucleotide identity values between the novel isolate and S. lactitubi M15^T, S. indicatrix WS40^T, S. maltophilia IAM 12423^T, S. pavanii LMG 25348^T, and Pseudomonas geniculata ATCC 19374^T were 87.2%, 87.3%, 86.3%, 88.0%, and 81.3%, respectively, suggesting the isolate was a novel species of the genus Stenotrophomonas. The DNA G + C content of TPQG1-4^T is 67.1 mol%. The major fatty acids were iso-C_15:0 (25.4%) and anteiso-C_15:0 (17.0%). The polar lipids of TPQG1-4^T included phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, amino phospholipid and phospholipid. Based on phenotypic and genotypic characteristics, the strain represents a novel species in the genus Stenotrophomonas, for which the name Stenotrophomonas cyclobalanopsidis sp. nov. is proposed. The type strain is TPQG1-4^T (= CFCC 15341^T = LMG 31208^T).

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

One Gram-stain-negative, aerobic, motile bacterial strain, 3-7^T, 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 DCY99^T (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, β-galactosidase, arginine dihydrolase and β-glucosidase. The major fatty acids were C_16 : 0, C_18 : 1ω7c and/or C_18 : 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 3-7^T 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 3-7^T (=CFCC 11561^T=LMG 30138^T).

Corticimicrobacter populi gen. nov., sp. nov., a member of the family Alcaligenaceae, isolated from symptomatic bark of Populus × euramericana canker

One Gram-negative aerobic bacterial strain was isolated from the bark tissue of Populus × euramericana and investigated using a polyphasic approach including 16S rRNA gene sequencing and both phenotypic and chemotaxonomic assays. The 16S rRNA gene and housekeeping gene phylogenies suggest that the novel isolate is different from the other genera of the family Alcaligenaceae. The G+C content, major fatty acids, physiological and biochemical data supported the distinctiveness of the novel strain from reference species. The major fatty acids detected in the novel isolate were C_16 : 1ω7c and/or C_16 : 1ω6c, C_16 : 0, C_14 : 0 3OH and/or C_16 : 1isoI and C_18 : 1ω7c. The phospholipid profile of strain d3-2-2^T contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, aminolipid, aminophospholipid and an unidentified lipid. The quinone of the novel isolate was Q-8. Therefore, based on the data, the strain constitutes a novel species of a novel genus within the family Alcaligenaceae, for which the name Corticimicrobacter populi gen. nov., sp. nov. is proposed. The type strain is 3d-2-2^T (=CFCC 11891^T=KCTC 52807^T).

Sinorhodobacter populi sp. nov., isolated from the symptomatic bark tissue of Populus × euramericana canker

We isolated five novel bacterial strains from symptomatic bark tissue of Populus × euramericana canker that were Gram-stain-negative, non-motile, aerobic oxidase-negative and catalase-positive. Growth occurred at 10-41 °C and at pH 5.0-7.0, with optimum growth at 30 °C and pH 7.0. Additionally, growth occurred in conditions of 0-5 % (w/v) salinity, but not above 7 % NaCl. The 16S rRNA gene sequences of the novel strains shared the highest similarity with Sinorhodobacter ferrireducens SgZ-3^T (97.1 %). The average nucleotide identity values between the novel strains and two type strains (S.inorhodobacter ferrireducens CCTCC AB2012026^T and 'Sinorhodobacter hungdaonensis' CGMCC 1.12963^T) were 78.4-78.9 %, which were lower than the proposed species boundary cut-off (95-96 %). The main polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, an unidentified lipid and phosphatidylcholine. The main respiratory quinone was Q-10, and major fatty acids were C18 : 1ω7c and/or C18 : 1ω6c. Based on data from a polyphasic taxonomy study, the novel strains represent a novel species of the genus Sinorhodobacter, for which the name Sinorhodobacter populi sp. nov. is proposed. The type strain is sk2b1^T (=CFCC 14580^T=KCTC 52802^T).

Ancrocorticia populi gen. nov., sp. nov, isolated from the symptomatic bark of Populus × euramericana canker

A Gram-staining positive facultative anaerobic, non-motile strain, sk1b4^T , was isolated from canker of symptomatic bark tissue of a Populus × euramericana. 16S rRNA gene sequence analyses showed that strain sk1b4^T shared the highest similarity with Arcanobacterium phocisimile (94.1%). Within the phylogenetic tree, the novel isolate formed a distinct branch from Actinobaculum, Arcanobacterium, and Trueperella. The percentage of conserved proteins calculated from genomic sequence indicated a low level of relatedness between the novel strain and its phylogenetic neighbors. Growth of the novel strain occurred at temperatures between 10 and 41°C, and within a pH range of 6.0-9.0; optimal growth occurred at 30°C and at pH 6.0-9.0. Growth also occurred within a NaCl concentration of 1%-5% (w/v). The major fatty acids of the strain were C_14:0 , C_16:0 , and C_18:1 ω9c_, and major polar lipids were glycolipid, phosphatidylinositol mannoside, phospholipid, diphosphatidylglycerol, and phosphatidylglycerol. Respiratory quinone was absent. On the basis of phenotypic and genotypic characteristics, we propose that the novel isolate should be classified as a novel species in a new genus: Ancrocorticia populi gen. nov., sp. nov. The type strain is sk1b4^T (=CFCC 14564^T = KCTC 39919^T ).

Brenneria corticis sp. nov., isolated from symptomatic bark of Populus×euramericana canker

A Gram-stain-negative, facultatively anaerobic, motile bacterial strain, designated gBX10-1-2^T, was isolated from symptomatic bark of Populus×euramericana canker in China. Phylogenetic analysis based on its 16S rRNA gene sequence showed that the novel isolate belonged to the genus Brenneria, and shared the highest sequence similarity to Brenneria nigrifluens LMG 2694^T (98.3 %). In the phylogenetic trees based on the four housekeeping genes sequences, the novel strain formed a separate branch different from B. nigrifluens LMG 2694^T, indicating that the novel strain should be classified as a novel species. The genome sequence-derived average nucleotide identity (ANI) values between the novel isolate and B. nigrifluens LMG 2694^T, Brenneria roseaesubsp. roseae FRB 222^T and Brenneria roseaesubsp. americana FRB 223^T were less than 85 %, lower than the proposed species boundary ANI cut-off value (95-96 %). The DNA G+C content was 56.2 mol%, and the main fatty acids were C16 : 0, C16 : 1ω7c, C18 : 1ω7c and C17 : 0cyclo. Based on the phenotypic and genotypic characteristics, strain gBX10-1-2^T represents a novel species of genus Brenneria, for which the name Brenneria corticis sp. nov. is proposed. The type strain is gBX10-1-2^T (=CFCC 11842^T=KCTC 42840^T).

Herbaspirillum piri sp. nov., isolated from bark of a pear tree

A Gram-stain-negative, aerobic, motile bacterial strain, shQ-4^T, was isolated from a pear tree in Henan Province, China. The strain grew at 10-41 °C, at pH 4.0-8.0 and in the presence of 1-3 % (w/v) NaCl. It shared highest 16S rRNA gene sequence similarity (96.66 %) with Herbaspirillum chlorophenolicum CPW301^T. The phylogenetic tree based on 16S rRNA gene sequences showed that strain shQ-4^T formed a distinct branch next to reference species in the genus Herbaspirillum. The profile of major polar lipids of strain shQ-4^T contained phosphatidylethanolamine (PE), diphosphatidylglycerol (DPG), phosphatidylglycerol (PG) and an unidentified aminophospholipid (APL). The major respiratory quinone was Q-8. The major fatty acids of this strain were C16 : 0, summed feature 3 (C16 : 1ω6c/C16 : 1ω7c), C17 : 0 cyclo and C18 : 0. Strain shQ-4^T is considered to represent a novel species of the genus Herbaspirillum, with the proposed name Herbaspirillum piri sp. nov. The type strain is shQ-4^T (=CFCC 14641^T=KCTC 52804^T).

Elevation of three subspecies of Lonsdalea quercina to species level: Lonsdalea britannica sp. nov., Lonsdalea iberica sp. nov. and Lonsdalea populi sp. nov

Four subspecies of Lonsdalea quercina (L. quercina subsp. quercina, L. quercina subsp. britannica, L. quercina subsp. iberica and L. quercina subsp. populi) were studied by genome sequence-derived average nucleotide identity (ANI), phylogenetic analysis based on 16S rRNA gene sequences, multilocus sequence analysis (MLSA) and phenotypic characteristics. In phylogenetic trees, based on 16S rRNA gene sequences, and in MLSA data, the four subspecies were divided into four subclusters in the Lonsdalea clade with high boot strap support. The ANI values between the four subspecies were 88.71-93.38 %, respectively, lower than the proposed species boundary ANI cut-off (95-96 %) that is considered the most important criterion to reclassify these subspecies at the species level. It is proposed that three subspecies be elevated to the species level as Lonsdalea britannica sp. nov. (type strain R-43280^T=LMG 26267^T=NCPPB 4481^T=CFCC 10822^T), Lonsdalea iberica sp. nov. (type strain R-44166^T=LMG 26264^T=NCPPB 4490^T=CFCC 10824^T) and Lonsdalea populi sp. nov. (type strain NY060^T=DSM 25466^T=NCAIM B 02483^T=LMG 27349^T=CFCC 13125^T).

Sphingobacterium humi sp. nov., isolated from soil

A Gram-stain-negative, facultatively aerobic bacterium, designated strain D1^T, was isolated from soil in South Korea. Cells of strain D1^T were non-motile rods with oxidase- and catalase-positive activities. Growth was observed at 15-40 °C (optimum, 30-37 °C), at pH 5.5-9.0 (optimum, pH 7.0-8.0) and in the presence of 0.0-5.0 % (w/v) NaCl (optimum, 0.0-1.0 %). The only respiratory quinone detected was menaquinone 7 (MK-7), and iso-C15 : 0, iso-C17 : 0 3-OH and summed feature 3 (comprising C16 : 1ω7c/C16 : 1ω6c) were identified as the major fatty acids. Phosphatidylethanolamine was the major polar lipid, and two unidentified glycophospholipids and four unidentified lipids were also detected as minor polar lipids. Sphingolipids, a typical chemotaxonomic feature of the genus Sphingobacterium, were detected. The G+C content of the genomic DNA was 43.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain D1^T formed a phyletic lineage with Sphingobacterium hotanense XH4^T within the genus Sphingobacterium. Strain D1^T was most closely related to S. hotanense XH4^T (98.1 % 16S rRNA gene sequence similarity) and Sphingobacterium cellulitidis R-53603^T (97.2 %), and the DNA-DNA relatedness level between strain D1^T and the type strain of S. cellulitidis was 43.1±0.7 %. Based on the phenotypic, chemotaxonomic and molecular features, strain D1^T clearly represents a novel species of the genus Sphingobacterium, for which the name Sphingobacterium humi sp. nov. is proposed. The type strain is D1^T (=KACC 18595^T=JCM 31225^T).

Sphingobacterium corticis sp. nov., isolated from bark of Populus × euramericana

A Gram-stain negative, aerobic, non-motile bacterial strain, 23D10-4-9^T, was isolated from symptomatic canker bark tissue of Populus × euramericana. The isolate grew between 4 and 35 °C, with optimal growth occurring at 25 °C. The species was positive for catalase and negative for oxidase activity. Nitrate was not reduced to nitrite. It showed activities toward β-galactosidase and β-glucosidase. Citrate was not utilized. Acid was produced from d-glucose. The major fatty acids were iso-C15 : 0, C16 : 1ω7c and iso-C17 : 0 3-OH. The main polar lipid profiles of the novel isolate included phosphatidylethanolamine, phospholipids and seven unknown lipids. The predominant menaquinone of the novel isolate was MK-7. The DNA G+C content was 40.6 mol%. 16S rRNA gene data revealed that the novel isolate shares the greatest sequence similarity with Sphingobacterium populi 7Y-4^T (96.1 %). Based on phenotypic and genotypic characteristics, the isolate represents a novel species within the genus Sphingobacterium, for which the name Sphingobacteriumcorticis sp. nov. is proposed. The type strain is 23D10-4-9^T (=CFCC 12640^T=KCTC 42248^T).

Sphingobacterium alkalisoli sp. nov., isolated from a saline-alkaline soil

A Gram-staining-negative, non-motile, non-spore-forming bacterium designated Y3L14T was isolated from the saline-alkaline soil of a farmland, Inner Mongolia, northern China. Strain Y3L14T could grow at 10-40 °C (optimally at 30 °C), pH 6.0-10.0 (optimally at pH 8.0), and in the presence of 0-6.0 % (w/v) NaCl (optimally with 0-2.0 %). Phylogenetic analysis based on the 16S rRNA gene and DNA gyrase subunit B (gyrB) gene sequences revealed that strain Y3L14T clustered with strains belonging to the genus Sphingobacterium, sharing the highest 16S rRNA gene sequence similarity with Sphingobacterium lactis WCC 4512T (94.99 %). Its major cellular fatty acids contained iso-C15 : 0, C16 : 0, iso-C17 : 0 3-OH and summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c). Menaquinone-7 (MK-7) was the only isoprenoid quinone. Strain Y3L14T contained phosphatidylethanolamine, sphingophospholipid, two unknown phospholipids and three unknown lipids as the major polar lipids. The genomic DNA G+C content of strain Y3L14T was 36.0 mol%. Based on the phenotypic, phylogenetic and genotypic characteristics, strain Y3L14T represents a novel species within the genus Sphingobacterium, for which Sphingobacterium alkalisoli sp. nov. is proposed; the type strain is Y3L14T (=CGMCC 1.15782T=KCTC 52379T).