Strain SYSU Research Articles

Network-directed efficient isolation of previously uncultivated Chloroflexi and related bacteria in hot spring microbial mats

The perplexity of the complex multispecies community interactions is one of the many reasons why majority of the microorganisms are still uncultivated. We analyzed the entire co-occurrence networks between the OTUs of Tibet and Yunnan hot spring samples, and found that less abundant OTUs such as genus Tepidimonas (relative abundant <1%) had high-degree centricity (key nodes), while dominant OTUs particularly genus Chloroflexus (relative abundant, 13.9%) formed the peripheral vertexes. A preliminary growth-promotion assay determined that Tepidimonas sp. strain SYSU G00190W enhanced the growth of Chloroflexus sp. SYSU G00190R. Exploiting this result, an ameliorated isolation medium containing 10% spent-culture supernatant of Tepidimonas sp. strain SYSU G00190W was prepared for targeted isolation of Chloroflexi in the Tibet and Yunnan hot spring samples. 16S rRNA gene fingerprinting characterized majority of the colonies isolated from these media as previously uncultivated Chloroflexi, of which 36 are potential novel species (16S rRNA sequence identity <98.5%). Metabolomes studies indicated that the spent-culture supernatant comprises several low-molecular-weight organic substrates that can be utilized as potential nutrients for the growth of these bacteria. These findings suggested that limited knowledge on the interaction of microbes provide threshold to traditional isolation method.

Lysinibacillus antri sp. nov., isolated from cave soil.

A Gram-stain-positive, motile, rod-shaped and endospore-forming strain, SYSU K30002T, was isolated from a soil sample collected from a karst cave in Xingyi county, Guizhou province, south-west China. SYSU K30002T grew at 28-40 °C (optimum, 37 °C), at pH 5.0-8.0 (optimum, pH 7.0) and in the presence of 0-4 % (w/v) NaCl (optimum in the absence of NaCl). The cell-wall peptidoglycan type was A4α (Lys-Asp). The cell-wall sugars of SYSU K30002T were ribose, galactose and mannose, and MK-7 was the menaquinone. The major fatty acids were iso-C15 : 0, C16 : 1 ω7c alcohol and iso-C16 : 0. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and two unidentified phospholipids. The G+C content of the genomic DNA was 36.1 mol%. The average nucleotide identity values between SYSU K30002T and its closest relatives were below the cut-off level (95-96 %) for species delineation. Based on phenotypic, chemotaxonomic and genome comparisons, strain SYSU K30002T represents a novel species of the genus Lysinibacillus, for which the name Lysinibacillusantri sp. nov. is proposed. The type strain is SYSU K30002T (=KCTC 33955T=CGMCC 1.13504T).

Lysinibacillus cavernae sp. nov., isolated from cave soil.

A Gram-staining positive, motile, rod-shaped and subterminal endospore-forming bacterium, designated strain SYSU K30005T, was isolated from a soil sample collected from a karst cave in Libo county, Guizhou province, south-western China. Strain SYSU K30005T showed the highest 16S rRNA gene sequence similarity with Lysinibacillus fusiformis (98.6%) and Lysinibacillus sphaericus (98.2%). In phylogenetic tree, strain SYSU K30005T clade with the members of the genus Lysinibacillus. Based on the phylogenetic and 16S gene sequence result, strain SYSU K30005T was affiliated to the genus Lysinibacillus. The growth of SYSU K30005T was observed at 15-37°C (optimum, 28°C), pH 6.0-9.0 (optimum, pH 7.0) and in the presence of 0-4% (w/v) NaCl (optimum in 3.5% NaCl). Cell wall peptidoglycan type was A4α (Lys-Asp). The cell-wall sugars of SYSU K30005T were ribose, galactose and mannose and MK-7 was the only quinone. The fatty acids (> 5% of total fatty acids) were iso-C15:0, anteiso-C15:0, iso-C16:0 and iso-C17:0. The polar lipids profile included diphosphatidylglycerol, phosphatideylglycerol, phosphatidylethanolamine and an unidentified phospholipid. The genomic DNA G + C content was 37.2mol%. The average nucleotide identity values between SYSU K30005T and its closest relatives were below the cut-off level (95-96%) for species delineation. The results support the conclusion that strain SYSU K30005T represents a novel species of the genus Lysinibacillus, for which we proposed the name Lysinibacillus cavernae sp. nov. The type strain is SYSU K30005T (= KCTC 43130T = CGMCC 1.17492T).

Roseibium aestuarii sp. nov., isolated from Pearl River Estuary.

A novel bacterium, designated strain SYSU M00256-3T, was isolated from a water sample collected from Pearl River Estuary at Guangzhou, PR China. Its taxonomic position was determined by using a polyphasic approach. Cells of the strain were Gram-staining-negative, motile, aerobic and rod-shaped with peritrichous flagella. It could grow at 15-45 °C, pH 4.0-10.0 and in the presence of 0-7.5 % (w/v) NaCl. The chemotaxonomic features of strain SYSU M00256-3T included ubiquinone-10 (Q-10) as the sole respiratory quinone; phosphatidylcholine, phosphatidylmethylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and an unidentified phospholipid as major polar lipids; summed feature 8 (C18 : 1 ω7c and C18 : 1 ω6c) as the predominant fatty acids (>70 %). On the basis of 16S rRNA gene sequence analysis, strain SYSU M00256-3T was most closely related to the type strains of Roseibium hamelinense CGMCC 1.12584T (97.7 %) and R. aquae CGMCC 1.12426T (97.2 %), R. sediminis KCTC 52373T (96.7 %), R. denhamense CGMCC 1.12583T (96.4 %). The average nucleotide identity (ANI) values between R. aestuarii SYSU M00256-3T and R. hamelinense CGMCC 1.12584T, R. aquae CGMCC 1.12426T, R. denhamense CGMCC 1.12583T and R. sediminis KCTC 52373T were 78.0, 78.2, 77.7 and 78.8, and the dDDH value is 20.0, 20.8, 20.1 and 20.6 correspondingly. Based on the analyses of the phenotypic, genotypic and phylogenetic characteristics, strain SYSU M00256-3T is characterized to represent a novel species of the genus Roseibium, for which the name Roseibium aestuarii sp. nov. is proposed. The type strain is SYSU M00256-3T (=NBRC 112946T=CGMCC 1.16156T).

Vitreimonas flagellata gen. nov., sp. nov., a novel member of the family Hyphomonadaceae isolated from an activated sludge sample

A coccobacilli-shaped proteobacterium, designated strain SYSU XM001T, was isolated from an activated sludge sample collected from JiMei sewage treatment plant, Xiamen, PR China. Cells were Gram-stain-negative, catalase-positive and oxidase-negative. The 16S rRNA gene sequence of strain SYSU XM001T shared less than 92 % sequence identities with members of the class Alphaproteobacteria, with highest sequence similarity to Aquidulcibacter paucihalophilus TH1-2T (91.6 %; family Hyphomonadaceae, order Rhodobacterales). The strain exhibited growth at 25-37 °C, pH 7.0-9.0 and in the presence of up to 1 % (w/v) NaCl. Its chemotaxonomic features included ubiquinone-10 as the respiratory isoprenologue, iso-C16 : 0, 10-methyl C16 : 0 TSBA and anteiso-C17 : 0 as major cellular fatty acids and monoglycosyldiglyceride, glucuronopyranosyldiglyceride and two unidentified glycolipids as the main polar lipids. The DNA G+C content was determined to be 62.9 % (draft genome). Analyses of the phylogenetic data and differences in the chemotaxonomic and biochemical features from related genera in the family Hyphomonadaceae indicated that strain SYSU XM001T merits representation of a novel species of a novel genus, for which the name Vitreimonas flagellata gen. nov., sp. nov. is proposed. The type strain of Vitreimonas flagellata is SYSU XM001T (=CGMCC 1.16661T=KCTC 62915T).

Description of Paenibacillus tepidiphilus sp. nov., isolated from a tepid spring.

China is a hotspot for hot springs and during microbial diversity analysis of Tengchong hot spring, Yunnan province, south-west PR China, two strains designated SYSU G01001T and SY-13 were isolated. SYSU G01001T and SY-13 were Gram-stain-positive, motile and spore-forming. Colonies were white, circular, raised and punctiform. SYSU G01001T and SY-13 grew at pH 6.0-9.0 (optimum pH 8.0) and at 23-37 °C (optimum 28 °C). The 16S rRNA gene sequence similarity between SYSU G01001T and SY-13 was 99.6 % but these strains shared low sequence similarity with Paenibacillus azotifigens (97.5 %) indicating that they represented a novel species. On the basis of the results, SYSU G01001T was selected for further investigations and SY-13 was considered to represent a second strain of the species. The cell wall peptidoglycan of SYSU G01001T was meso-2,6-diaminopimelic acid and MK-7 was the only respiratory quinone. The polar lipids were diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), two unidentified aminolipids (AL), two unidentified amino phospholipids (APL), an unidentified phospholipid (PL) and an unidentified polar lipid (L). The G+C content of the genomic DNA was 53.9 mol%. The average nucleotide identity (ANIb and ANIm) values between SYSU G01001T and Paenibacillus azotifigens LMG 29963T were below the cut-off level (95-96 %) recommended as the average nucleotide identity (ANI) criterion for interspecies identity. On the basis of the above results strain SYSU G01001T represents a novel species of the genus Paenibacillus, for which the name Paenibacillus tepidiphilus sp. nov. is proposed. The type strain is SYSU G01001T (=KCTC 33952T=CGMCC 1.13870T).

Lysobacter prati sp. nov., isolated from a plateau meadow sample.

A novel proteobacterial strain designated SYSU H10001T was isolated from a soil sample collected from plateau meadow in Hongyuan county, Sichuan province, south-western China. The taxonomic position of the strain was investigated using a polyphasic approach. On the basis of 16S rRNA gene sequence similarities and phylogenetic analysis, strain SYSU H10001T was most closely related to Lysobacter soli KCTC 22011T (98.6%, sequence similarity) and Lysobacter panacisoli JCM 19212T (98.2%). The prediction result of secondary metabolites based on genome shown that the strain SYSU H10001T contained 3 clusters of bacteriocins, 1 cluster of non-ribosomal peptide synthetase, 1 cluster of type 1 polyketide synthase and 1 cluster of arylpolyene. In addition, the major isoprenoid quinone was Q-8 and the major fatty acids were identified as iso-C15:0, iso-C17:0 and Summed feature 9. The polar lipids contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and three unidentified phospholipids. The genomic DNA G + C content of strain SYSU H10001T was 66.5% (genome). On the basis of phenotypic, genotypic and phylogenetic data, strain SYSU H10001T represents a novel species of the genus Lysobacter, for which the name Lysobacter prati sp. nov. is proposed. The type strain is SYSU H10001T (= KCTC 72062T = CGMCC 1.16662T).

Streptomyces cavernae sp. nov., a novel actinobacterium isolated from a karst cave sediment sample.

A novel actinobacterial strain, designated SYSU K10008T, was isolated from a soil sample collected from a karst cave in Xingyi County, Guizhou Province, south-western PR China. The taxonomic position of the strain was investigated by using a polyphasic approach. Cells of the strain were aerobic, Gram-stain-positive and non-motile. On the basis of 16S rRNA gene sequence similarities and the results of phylogenetic analysis, strain SYSU K10008T was most closely related to Streptomyces cyaneus CGMCC 4.1671T, and shared the highest sequence identity of 98.3 % based on the NCBI database. In addition, ll-diaminopimelic acid was the diagnostic diamino acid in cell-wall peptidoglycan. The whole-cell sugars were glucose and rhamnose. The major isoprenoid quinone was MK-9(H6), while the major fatty acids (>10 %) were C16 : 0, iso-C16 : 0, anteiso-C15 : 0 and summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c). The polar lipids contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside and one unidentified lipid. The genomic DNA G+C content of strain SYSU K10008T was 70.5 mol%. On the basis of phenotypic, genotypic and phylogenetic data, strain SYSU K10008T represents a novel species of the genus Streptomyces, for which the name Streptomyces cavernae sp. nov. is proposed. The type strain is SYSU K10008T (=KCTC 39850T=DSM 104115T).

Facilibium subflavum gen. nov., sp. nov. and Cysteiniphilum halobium sp. nov., new members of the family Fastidiosibacteraceae isolated from coastal seawater

Two Francisella-like bacteria, designated strains SYSU SYW-5T and SYSU SYW-6T, were isolated from coastal seawater sampled at Huizhou Double-Moon Bay, Guangdong Province, PR China. Cells were found to be Gram-stain-negative, non-motile, non-spore-forming and of pleomorphic shape (coccobacilli or rod). Chemotaxonomic analysis of the plasma membrane revealed ubiquinone-8 as the respiratory quinone, and saturated branched-chain (anteiso-C15 : 0) and saturated straight-chain (C18 : 0) fatty acids as major components (>8 % of total fatty acid). The major polar lipids comprised diphosphatidylglycerol (cardiolipin), phosphatidylethanolamine, phosphatidylglycerol and phosphatidylcholine, as well as an unidentified aminophospholipid and an unidentified phospholipid in SYSU SYW-5T, and two unknown polar lipids in SYSU SYW-6T. Comparison of 16S rRNA gene sequences showed that SYSU SYW-5T had maximum similarity to Fastidiosibacter lacustris SYSU HZH-2T (93.4 %), while SYSU SYW-6Thad maximum similarity to Cysteiniphilum litorale SYSU D3-2T (97.5 %). Phylogenetic dendrograms based on 16S rRNA genes and 31 concatenated protein markers revealed that the two novel strains represent a distinct lineage within the family Fastidiosibacteraceae. The average nucleotide identity and in silico DNA-DNA hybridization values between the two isolates and their related species were well below the threshold limit for species delineation (<89.2 and <35 %, respectively). Based on the above results, strain SYSU SYW-5T is proposed to be a novel species of a new genus with the name Facilibium subflavum gen. nov., sp. nov. (SYSU SYW-5T = DSM 103991T= KCTC 52556T), and strain SYSU SYW-6T is proposed to be a novel species of genus Cysteiniphilum with the name Cysteiniphilumhalobium sp. nov. (SYSU SYW-6T=DSM 103992T=KCTC 52558T).

Description of Paenibacillus antri sp. nov. and Paenibacillus mesophilus sp. nov., isolated from cave soil.

Two Gram-positive, rod-shaped, motile, endospore-forming strains, SYSU K30003T and SYSU K30004T, were isolated from cave soil sampled in Xingyi County, Guizhou Province, south-west PR China. The 16S rRNA gene sequence results indicated that strains SYSU K30003T and SYSU K30004T had highest sequence similarities to Paenibacillus thermoaerophilus DSM 26310T (93.2 %) and Paenibacillus haemerocallicola KCTC 33185T (97.8 %), respectively. Optimum growth for both strains occurred at pH 7.0 and 37 °C. Both strains contained meso-2,6-diaminopimelic acid in their cell-wall peptidoglycan and MK-7 was the only isoprenoid quinone detected. The polar lipid profile of strain SYSU K30004T consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, two aminophospholipids, an unidentified glycolipid, unidentified phospholipids and two unidentified polar lipids. The polar lipid profile of strain SYSU K30003T contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and an unidentified glycolipid. The major fatty acids (>5 %) of strain SYSU K30003T were anteiso-C15:0, C16 : 0, anteiso-C17 : 0 and iso-C16 : 0, while those of strain SYSU K30004T were anteiso-C15:0, C16:0, anteiso-C17 : 0, iso-C15 : 0, iso-C16:0 and iso-C17 : 0. The genome G+C contents of strains SYSU K30003T and SYSU K30004T were 59.0 and 53.6 mol%, respectively. The average nucleotide identity values between strains SYSU K30003T and SYSU K30004T and other closely related Paenibacillus members were below the cut-off level (95-96 %) for species identification. Based on the results of phenotypic, chemotaxonomic and genome analyses, strains SYSU K30003T and SYSU K30004T represent two novel species of the genus Paenibacillus, for which the names Paenibacillus antri sp. nov. and Paenibacillus mesophilus sp. nov. are proposed. The type strains are SYSU K30003T (=KCTC 33956T=CGMCC 1.13505T) and SYSU K30004T (=KCTC 33957T=CGMCC 1.13872T).

Microlunatus speluncae sp. nov., a novel actinobacterium isolated from a Karstic subterranean environment sample.

A novel actinobacterial strain, designated SYSU K12189T, was isolated from a soil sample collected from a Karst cave in Xingyi county, Guizhou province, south-western China. The taxonomic position of the strain was investigated using a polyphasic approach. Cells of the strain were observed to be aerobic and Gram-stain positive. On the basis of 16S rRNA gene sequence similarities and phylogenetic analysis, strain SYSU K12189T is closely related to the type strains of the genus Microlunatus, Microlunatus parietis 12-Be-011T (98.5% sequence similarity), Microlunatus nigridraconis CPCC 203993T (98.4%) and Microlunatus cavernae YIM C01117T (96.6%), and is therefore considered to represent a member of the genus Microlunatus. DNA-DNA hybridization values between strain SYSU K12189T and related type strains of the genus Microlunatus were <70%. In addition, LL-diaminopimelic acid was found to be the diagnostic diamino acid in the cell wall peptidoglycan. The major isoprenoid quinone was identified as MK-9(H4), while the major fatty acids (> 10%) were found to be anteiso-C15:0, iso-C15:0, iso-C16:0 and iso-C14:0. The polar lipids were found to contain diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, three glycolipids and two unidentified lipids. The genomic DNA G+C content of strain SYSU K12189T was determined to be 69.4mol%. On the basis of phenotypic, genotypic and phylogenetic data, strain SYSU K12189T is concluded to represent a novel species of the genus Microlunatus, for which the name Microlunatus speluncae sp. nov. is proposed. The type strain is SYSU K12189T (=KCTC 39847T = DSM103947T).

A xylan-degrading thermophilic and obligate anaerobe Xylanivirga thermophila gen. nov., sp. nov., isolated from an anammox dominant wastewater treatment plant, and proposal of Xylanivirgaceae fam. nov.

In our search for novel anaerobes with potential carbohydrate polymers degrading activity, we have isolated a xylan-degrading bacterial strain SYSU GA17129T from an anammox bacteria dominant wastewater treatment plant. Phylogenetic analysis of the 16S rRNA gene sequence indicated the strain SYSU GA17129T belong to the order Clostridiales and shared highest sequence identity with Caldicoprobacter faecalis DSM 20678T (89.9%). The strain was thermophilic, obligately anaerobic, non-motile and rod shaped. Optimum growth of the strain was observed at 45 °C, pH 8.0 and in the presence of 0.5% NaCl (w/v). The chemotaxonomic features of the strain SYSU GA17129T comprised of C14:0 FAME, iso-C15:0 FAME and C16:0 FAME as the major fatty acids (>10%), diphosphatidylglycerol, phosphatidylinositol mannoside, an unidentified phospholipid, three unidentified polar lipids and two unidentified glycolipids as its polar lipids, and meso-diaminopimelic acid (meso-DAP) as the diamino acid in peptidoglycan. The G + C content of the genomic DNA was 35.9%. The strain could be distinguished from other defined families within the order Clostridiales by the differences in phenotypic and physiological characteristics, distinct phylogenetic lineage in 16S rRNA gene- and genome-based phylogenies and low genomic relatedness index. Based on these distinguishing properties, strain SYSU GA17129T is proposed to represent a new species of a new genus Xylanivirga thermophila gen. nov., sp. nov., within a new family Xylanivirgaceae fam. nov. The type species of the new taxon is SYSU GA17129T (=KCTC 15754T = CGMCC 1.5282T). This strain is characterized within the order Clostridiales, class Clostridia of the phylum Firmicutes.

Rhabdothermincola sediminis gen. nov., sp. nov., a new actinobacterium isolated from hot spring sediment, and emended description of the family Iamiaceae.

One thermophilic bacterium, designated strain SYSU G02662T, was isolated from hot spring sediment sampled in Tibet, PR China. Polyphasic taxonomic analyses and whole-genome sequencing were used to determine the taxonomy position of the strain. Phylogenetic analysis using 16S rRNA gene sequences indicated that strain SYSU G02662T showed the highest sequence similarity to Actinomarinicola tropica SCSIO 58843T (95.1 %). The strain could be differentiated from other species of the family Iamiaceae by its distinct phenotypic and genotypic characteristics. Cells of strain SYSU G02662T were aerobic, Gram-staining-positive and short rodshaped. Growth occurred optimally at 45 °C and pH 7.0. In addition, meso-diaminopimelic acid was the diagnostic diamino acid in the cell-wall peptidoglycan. The respiratory quinone was MK-9 (H8), while the major fatty acids (>10 %) were C16 : 0, C17 : 0, C18 : 0 and iso-C16 : 0. The detected polar lipids included diphosphatidylglycerol, phosphatidylinositol mannoside and phosphatidylinositol. The G+C content of the genomic DNA was 70.5 % based on the draft genomic sequence. On the basis of phenotypic, genotypic and phylogenetic data, strain SYSU G02662T represents a novel species of a novel genus in the family Iamiaceae, for which the name Rhabdothermincola sediminis gen. nov., sp. nov. is proposed. The type strain of the proposed novel species is SYSU G02662T (=CGMCC 4.7688T=KCTC 49500T).

Transcriptomic analysis of two endophytes involved in enhancing salt stress ability of Arabidopsis thaliana

Soil salinity is one of the serious environmental issues worldwide. In the present study, we made an attempt to isolate endophytic actinobacteria from halophyte and evaluate their growth promoting ability in Arabidopsis thaliana under salt stress through transcriptomic analysis. Two endophytic strains SYSU 333322 and SYSU 333140 were isolated and 16S rRNA gene sequence analysis suggests that these strains belong to Arthrobacter endophyticus and Nocardiopsis alba, respectively. To evaluate the growth promoting ability of two strains in Arabidopsis thaliana four experimental set up were designed. Set up designated s322 and s140 includes strains SYSU 333322 and SYSU 333140, respectively inoculated with A. thaliana under salt stress; set up designated MS322 and MS140 includes strains SYSU 333322 and SYSU 333140, respectively inoculated with A. thaliana without salt stress; MS includes seedlings without bacterial strains and salt stress; C150 includes seedlings grown in 150 mmol L−1NaCl. A. endophyticus strain SYSU 333322 and N. alba strain SYSU 333140 were efficient to promote A. thaliana growth under salt stress A. endophyticus strain SYSU 333322 was more efficient than N. alba strain SYSU 333140 for growth promotion. Although A. endophyticus strain SYSU 333322 and N. alba strain SYSU 333140 were isolated from the same host, their mechanism of growth promotion in A. thaliana under salt stress was different. Gene encoding for chlorophyll a reductase, peptide-methionine (R)-S-oxide reductase, and potassium ion uptake were up-regulated when A. thaliana inoculated with strain SYSU 333322 and SYSU 333140 under salt stress. Pathways such as carotenoid biosynthesis, phenylalanine metabolism, phenylpropanoid biosynthesis, glycerolipid metabolism, and nitrogen metabolism played a crucial role in enhancing the salt stress tolerance of A. thaliana. Our results suggest that different bacteria have a different mechanism to promote plant growth under salt stress and hence it is necessary to understand the mechanism to overcome soil salinity problem.

Bacillus antri sp. nov., isolated from cave soil

A Gram-stain-positive, strictly aerobic, rod-shaped, motile, endospore-forming strain, SYSU K30001T, was isolated from a soil sample collected from a cave in Xingyi county, Guizhou province, south-west China. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SYSU K30001T belonged to the genus Bacillus, with the highest sequence similarity to the type strain of Bacillus panaciterrae (98.1 %). Growth occurred at pH 6.0-9.0 (optimum, pH 7.0), at 28-55 °C (optimum, 28 °C) and in the presence of 0-3 % (w/v) NaCl (optimum in the absence of NaCl). Strain SYSU K30001T contained meso-2,6-diaminopimelic acid in the cell-wall peptidoglycan and MK-7 as the only isoprenoid quinone present. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and an unidentified glycolipid. The major fatty acids were iso-C15 : 0, iso-C17 : 1ω10c, anteiso-C14 : 0 and iso-C17 : 0. The genome G+C content was 39.8 mol%. The average nucleotide identity values between SYSU K30001T and B. panaciterrae DSM 19096T were 72.1 % (ANIb) and 83.1 % (ANIm), which were below the cut-off level (95-96 %) for species delineation. Based on phenotypic, chemotaxonomic and molecular characterizations, strain SYSU K30001T represents a novel species of the genus Bacillus, for which the name Bacillus antri sp. nov. is proposed. The type strain is SYSU K30001T (=KCTC 33954T=CGMCC 1.13871T).

Aestuariisphingobium litorale gen. nov., sp. nov., a novel proteobacterium isolated from a water sample of Pearl River estuary.

Strain SYSU M10002T was isolated from a water sample collected from the coastal region of Pearl River estuary, Guangdong Province, southern China. The taxonomic position of the isolate was investigated by polyphasic taxonomic approaches. The isolate was found to be Gram-negative, non-motile, short rods and aerobic. The strain was able to grow at 14-37°C, pH 6.0-10.0 and in the presence of up to 0.5% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SYSU M10002T is a member of the family Sphingomonadaceae, with high sequence similarity to Sphingorhabdus buctiana T5T (95.1%). Overall genomic related indices between the genome of strain SYSU M10002T and those of related strains were low to moderate (AAI values < 64.3%; POCP values < 58%), indicating that strain SYSU M10002T represents a novel lineage within the family Sphinogomonadaceae. Strain SYSU M10002T contained homospermidine as its polyamine. The major polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, sphingoglycolipid, two unidentified phospholipids and an unidentified aminolipid. Ubiquinone Q-9 (44.9%) and Q-10 (43.2%) were the dominant respiratory quinones, along with a minor amount of Q-8 (11.9%). The predominant cellular fatty acids (> 10%) identified were summed feature 3 (C16:1ω7c and/or C16:1ω6c), summed feature 8 (C18:1ω7c) and C14:0 2-OH. The genomic DNA G+C content was 64.0%. Based on the analyses of the phenotypic, genotypic and phylogenetic characteristics, strain SYSU M10002T is determined to represent a novel species of a novel genus, for which the name Aestuariisphingobium litorale gen. nov., sp. nov. is proposed. The type strain of the species is SYSU M10002T (= KCTC 52944T = NBRC112961T).

Novosphingobium meiothermophilum sp. nov., isolated from a hot spring.

A moderately thermophilic, aerobic, Gram-stain-negative, non-spore-forming, rod-shaped and yellow-pigmented bacterium, designated strain SYSU G00007T, was isolated from a hot spring slurry sample. Optimum growth was observed at 37-45 °C and pH 7. Pairwise comparison of the 16S rRNA gene sequence of strain SYSU G00007T and other Novosphingobium species showed sequence similarities ranging from 93.7 to 97.9 %. Strain SYSU G00007T showed highest sequence identity to Novosphingobium subterraneum DSM 12447T (97.9 %). The average nucleotide identities and digital DNA-DNA hybridization values between strain SYSU G00007T and its closely related phylogenetic neighbours were below 81 and 31 %, respectively, indicating that strain SYSU G00007T represented a novel species of the genus Novosphingobium. The DNA G+C content of strain SYSU G00007T was 64.3 % (genome). The major respiratory quinone was ubiquinone Q-10. The polar lipid profile included diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, two sphingoglycolipids, two unidentified phospholipids, two unidentified aminophospholipids and two unidentified polar lipids. Spermidine was the only polyamine detected. The major fatty acids were C19 : 0cyclo ω8c, summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c) and C16 : 0. The results obtained from phylogenetic, chemotaxonomic and phenotypic analyses support the conclusion that strain SYSU G00007T represents a novel species of the genus Novosphingobium, for which we proposed the name Novosphingobiummeiothermophilum sp. nov. The type strain is SYSU G00007T (=KCTC 52672T=CCTCC AB2017010T).

Botryobacter ruber gen. nov., sp. nov., a novel member of the family Hymenobacteraceae.

Strain SYSU D60016T, a rod-shaped bacterium that tends to form clusters, was isolated from a soil sample collected from the Gurbantunggut desert, China. Cells were Gram-stain-negative, catalase-negative and oxidase-positive. The 16S rRNA gene sequence of strain SYSU D60016T shared less than 94 % sequence identity with members of the family Hymenobacteraceae. The strain exhibited growth at 15-50 °C, pH 6-8 and in the presence of up to 3 % (w/v) NaCl. Its chemotaxonomic features included MK-7 as the respiratory menaquinone, iso-C15 : 0 and summed feature 4 (iso-C17 : 1 I and/or anteiso-C17 : 1 B) as major cellular fatty acids and phosphatidylethanolamine as the main polar lipid. The DNA G+C content was determined to be 50.1 % (genome). Analyses of the phylogenetic data and differences in the chemotaxonomic and biochemical features from related genera in the family Hymenobacteraceae indicated that strain SYSU D60016T merits representation of a novel species of a novel genus in the family Hymenobacteraceae. The name Botryobacter ruber gen. nov., sp. nov. is, therefore, proposed to represent the phylogenetic position of strain SYSU D60016T in the family Hymenobacteraceae. The type strain of the proposed new taxon is SYSU D60016T (=KCTC 52794T=NBRC 112957T).

Calidifontimicrobium sediminis gen. nov., sp. nov., a new member of the family Comamonadaceae.

Two Gram-stain-negative and facultative anaerobic bacteria, designated strains SYSU G00088T and YIM 73032, were isolated from sediment samples collected from hot springs in Tibet, China. Based on the analyses of the 16S rRNA gene sequences, the two isolates were observed to be a member of the family Comamonadaceae, sharing highest pairwise sequence identity with type strains of Piscinibacter defluvii SH-1T (97.8 and 97.7 %, respectively). They were able to grow in the temperature range of 37-50 °C, pH 5.0-9.0 and in the presence of up to 0.5 % (w/v) NaCl. Both strains were positive for catalase and oxidase reactions. Cells of the novel isolates were short-rods and motile by means of a polar flagellum. The chemotaxonomic features of the two strains include ubiquinone 8 as the respiratory isoprenologue, diphosphatidylglycerol, phosphatidylethanolamine and phoshatidylglycerol as the known polar lipids, and C16 : 0 and C17 : 0cyclo as major fatty acids. The genomic DNA of strains SYSU G00088T and YIM 73032 had G+C contents of 71.8 and 71.9%, respectively. Based on the analyses of the phylogenetic, chemotaxonomic, morphological and genomic data, the two isolates are considered to represent a novel species of a new genus, for which the name Calidifontimicrobium sediminis gen. nov., sp. nov. is proposed. The type strain of Calidifontimicrobium sediminis is SYSU G00088T (=KCTC 52671T=CGMCC 1.13597T).

Flaviflagellibacter deserti gen. nov., sp. nov., a novel member of the order Rhizobiales isolated from a desert soil.

A motile, rod-shaped and yellow coloured proteobacterium, designated strain SYSU D60017T, was isolated from a desert soil sample. The bacterium was found to be an obligately aerobic, mesophilic and neutrophilic chemo-heterotroph. Cells were observed to be Gram-stain negative, catalase positive and oxidase positive. The major cellular fatty acids were identified as C19:0ω8c cyclo and Summed Feature 8 (C18:1ω7c and/or C18:1ω6c). The main respiratory quinone identified was ubiquinone-10. The DNA G + C content was determined to be 63.8% based on draft genome sequence data. The polar lipids detected were identified as diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and five unidentified polar lipids. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SYSU D60017T is a member of the order Rhizobiales, but forms a distinct phylogenetic lineage. The differences in the phenotypic characteristics from members of related genera and its distinct phylogenetic position suggested that the isolate SYSU D60017T represents a novel species of a novel genus within the order Rhizobiales, for which the name Flaviflagellibacter deserti gen. nov., sp. nov. is proposed. The type strain of the new taxon is SYSU D60017T (= CGMCC 1.16444T = NBRC 112958T).