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An actinobacterial strain, designated R-N-C8T, was isolated from the rhizosphere soil of Arabidopsis thaliana collected in Yunnan Province, south-west China. Based on the results of 16S rRNA gene sequence analysis, strain R-N-C8T had highest similarity to Nocardioides terrae CGMCC 1.7056T (96.5%), Nocardioides opuntiae KCTC 19804T (96.3%) and Nocardioides currus IB-3T (96.1%), and lower than 96.0 % similarity to other members of the genus Nocardioides . Phylogenetic trees based on 16S rRNA gene sequences indicated that strain R-N-C8T formed an isolated branch with N. terrae CGMCC 1.7056T and N. opuntiae KCTC 19804T. The polar lipids contained phosphatidylglycerol, diphosphatidylglycerol, one unidentified phosphoglycolipid and four unidentified phospholipids in the cellular membrane. The major fatty acids were identified as iso-C16 : 0, anteiso-C17 : 0, iso-C17 : 0, summed feature 9 (iso-C17 : 1 ω9c and/or C16 : 0 10-methyl) and iso-C15 : 0. The predominant respiratory quinone was MK-8(H4) and ll-diaminopimelic acid was the diagnostic diamino acid in the cell-wall peptidoglycan. The genomic DNA G+C content was 70.9 mol%. The orthologous average nucleotide identiy values between N. terrae CGMCC 1.7056T, N. currus IB-3T and strain R-N-C8T were 77.1 and 75.1 %, respectively. DNA–DNA hybridization values between N. terrae CGMCC 1.7056T, N. currus IB-3T and strain R-N-C8T were 20.7 and 19.9 % respectively. Data from phenotypic and genotypic analyses supported that strain R-N-C8T represents a new species of Nocardioides , for which the name Nocardioides nematodiphilus sp. nov. is proposed. The type strain is R-N-C8T (=CGMCC 1.18723T= KCTC 49528T).

A Gram-staining negative, aerobic, non-motile and rod-shaped bacterium, designated strain N-S-14

An investigation of the diversity of 1-aminocyclopropane-1-carboxylate deaminase producing bacteria associated with camel faeces revealed the presence of a novel bacterial strain designated C459-1T. It was Gram-stain-negative, short-rod-shaped and non-motile. Strain C459-1T was observed to grow optimally at 35 °C, at pH 7.0 and in the presence of 0 % NaCl on Luria–Bertani agar medium. The cells were found to be positive for catalase and oxidase activities. The major fatty acids (>10 %) were identified as iso-C15 : 0, summed feature 3 (C16 : 1 ω6c and/or C16 : 1 ω7c) and iso-C17 : 0 3-OH. The predominant menaquinone was MK-7. The major polar lipids consisted of phosphatidylethanolamine, one sphingophospholipid, two unknown aminophospholipids, three unknown glycolipids and five unknown lipids. The genomic DNA G+C content was 40.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain C459-1T was affiliated with the genus Sphingobacterium and had the highest sequence similarity to Sphingobacterium tabacisoli h337T (97.0 %) and Sphingobacterium paucimobilis HER1398T (95.6 %). The average nucleotide identity and digital DNA–DNA hybridization values between strain C459-1T and S. tabacisoli h337T were 83.8 and 33.8 %, respectively. Phenotypic characteristics including enzyme activities and carbon source utilization differentiated strain C459-1T from other Sphingobacterium species. Based on its phenotypic, chemotaxonomic and phylogenetic properties, strain C459-1T represents a novel species of the genus Sphingobacterium , for which the name Sphingobacterium faecale sp. nov. is proposed, with strain is C459-1T (CGMCC 1.18716T=KCTC 82381T) as the type strain.

A Gram-stain-negative, facultative anaerobic, motile and straight rod-shaped bacterium, designated strain C1-9T, was isolated from rhizosphere soil of Camellia sinensis (L.) O. Ktze collected from a tea garden in Huize, south-western PR China. Cells were oxidase-positive and catalase-negative. Growth occurred at 20–40 °C and pH 6.0–10.0, with an optimal growth at 30 °C and pH 7.0. The respiratory quinone was detected as ubiquinone-8 (Q-8). The major fatty acids were identified as summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C16 : 0 and summed feature 8 (C18 : 1ω7c or C18 : 1ω6c). The cellular polar lipids contained phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, three unidentified phospholipids, two unidentified lipids, one unidentified aminophospholipid and one unidentified aminolipid. The polyamine types were detected as 1,8-diaminooctane and 2-hydroxyputrescine. The genomic DNA G+C content was 68.6 mol%. Based on the results of 16S rRNA gene sequence analysis, strain C1-9T (MF687442) showed highest sequence similarity to Rivibacter subsaxonicus DSM 19570T (97.1 %). The phylogenetic tree based on 16S rRNA gene sequences showed that strain C1-9T clustered close to R. subsaxonicus DSM 19570T, Methylibium petroleiphilum CCTCC AB 2014193T and species belonging to the genera Rhizobacter and Piscinibacter . The phylogenomic tree indicated that strain C1-9T formed a clade with R. subsaxonicus . The average nucleotide identity value was 76.0 % between strain C1-9T and R. subsaxonicus DSM 19570T, which is lower than the prokaryotic species delineation threshold of 95.0–96.0 %. The polyphasic taxonomic characteristics indicated that strain C1-9T represents a novel species of a new genus within the order Burkholderiales , for which the name Pseudorivibacter rhizosphaerae gen. nov., sp. nov. (type strain C1-9T = KCTC 62325T=CGMCC 1.13864T) is proposed.

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).

A Gram-stain negative, aerobic, motile and rod-shaped bacterium, designated strain 3.1105T, was isolated from a karst district soil sample collected from Tiandong cave, Guizhou province, south-west PR China. The isolate grew at 10–40 °C and pH 5.0–8.0 and tolerated up to 1 % NaCl (w/v) on R2A medium, with optimal growth at 25–30 °C, pH 7.0 and 0 % NaCl (w/v). Cells showed oxidase-positive and catalase-positive reactions. The respiratory quinone was Q-10. The predominant cellular fatty acids contained C18 : 1ω7c 11-methyl, summed feature 8 (C18 : 1ω7c or C18 : 1ω6c), C16 : 0 and C17 : 0. The major polar lipids were phosphatidylglycerol and monoglycosyldiglycerides. The genomic DNA G+C content was 56.0 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that 3.1105T should be affiliated to the genus Asticcacaulis and showed highest 16S rRNA gene sequence similarity values with Asticcacaulis excentricus CB 48T (96.0 %), Asticcacaulis endophyticus ZFGT-14T (95.3 %) and lower than 95.3 % similarity to other species of the genus Asticcacaulis . The polyphasic taxonomic characteristics indicated that strain 3.1105T represents a novel species of the genus Asticcacaulis , for which the name Asticcacaulis tiandongensis sp. nov., (type strain 3.1105T=KCTC 62978T=CCTCC AB 2018268T) is proposed.

A Gram-stain-negative, yellow-green bacterium, designated 1.1416T, was isolated from wormcast of Eisenia foetida. The strain was non-motile, rod-shaped, and grew optimally on NA medium at 30 °C, pH 7.0 and with 0 % (w/v) NaCl. On the basis of the 16S rRNA gene sequence and phylogenetic analysis, 1.1416T showed the highest degree of 16S rRNA gene sequence similarity to Luteimonas arsenica 26-35T (96.2 %), followed by Luteimonas lutimaris G3T (96.1 %). The respiratory quinone of 1.1416T was ubiquinone-8 (Q-8), and its major cellular fatty acids were iso-C15 : 0 (39.8 %), summed feature 9 (iso-C17 : 1 ω9c or C16 : 0 10-methyl) (18.6 %). The major polar lipids of 1.1416T were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and six unidentified phospholipids. The genomic DNA G+C content of 1.1416T was 71.0 mol%. According to the results of the phenotypic and chemotaxonomic phylogenetic analyses, strain 1.1416T represents a novel species of the genus Luteimonas, for which the name Luteimonas lumbrici sp. nov. is proposed, with strain 1.1416T (=KCTC 62979T=CCTCC AB 2018348T) as the type strain.

A Gram-stain-negative, rod-shaped, non-motile, aerobic, catalase-negative and oxidase-positive bacterium, designated strain Sn-9-2T, was isolated from a cave soil sample collected from Tiandong cave, Guizhou Province, south-west PR China. Growth occurred at 15–40 °C (optimum, 30 °C), at pH 5.0–9.0 (optimum, pH 7.0–8.0) and with 0–1 % NaCl (w/v). The predominant respiration quinone was ubiquinone-10 (Q-10). The major cellular fatty acids were summed feature 8 (C18 : 1ω7c or C18 : 1ω6c; 83.9 %) and C16 : 0 (5.8 %). The major polar lipids were phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylcholine, phosphatidylglycerol, three unidentified phospholipids, two unidentified glycolipids, two unidentified polar lipids and one unidentified aminolipid. The DNA G+C content of strain Sn-9-2T was 67.5 mol%. Based on the results of 16S rRNA gene sequence analysis, the nearest phylogenetic neighbours of strain Sn-9-2T (MF958452) were identified as Aquabacter spiritensis (FR733686) DSM 9035T (97.5 %), Xanthobacter autorophicus (jgi.1053054) DSM 432T (97.2 %) and Xanthobacter tagetidis ATCC 700314T RCTF01000015 (96.9 %). The average nucleotide identity values were 78.0, 77.4 and 77.6 % and the digital DNA–DNA hybridization values were 21.8, 22.0 and 18.8 % between strain Sn-9-2T and A. spiritensis DSM 9035T, X. autotrophicus DSM 432T and X. tagetidis DSM 11105T, respectively. The DNA–DNA hybridization data indicated that strain Sn-9-2T represented a novel genomic species. On the basis of the results of phylogenetic analysis, chemotaxonomic data, physiological characteristics and DNA–DNA hybridization data, strain Sn-9-2T should represent a novel species of the genus Aquabacter , for which the name Aquabacter cavernae sp. nov. is proposed. The type strain is Sn-9-2T (=KCTC 62308T=CCTCC AB 2018270T).

A Gram-stain-negative, aerobic, non-motile and rod-shaped bacterium, designated strain L4-6T, was isolated from an arable soil sample of tobacco in Huize, south-western China and subjected to polyphasic taxonomic characterization. The cells showed oxidase-positive and catalase-positive reactions. Growth occurred at 20–35 °C, at pH 5.0–8.0 and with 0–2 % (w/v) NaCl, optimally at 30 °C, pH 6.0–7.0 and 0–1 % (w/v) NaCl. The major respiratory lipoquinone was ubiquinone-8. The predominant cellular fatty acids (>10.0 %) were identified as summed feature 9 (iso-C17 : 1ω9c or C16 : 0 10-methyl), iso-C15 : 0 and iso-C17 : 0. The polar lipid profile contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, two unidentified phospholipids, two unidentified aminophospholipids and five unidentified aminolipids. The genomic DNA G+C content was 60.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain L4-6T should be affiliated to the genus Dyella and formed a clade with the most closely related organism Dyella soli JS12-10T. 16S rRNA gene sequences similarity analysis showed that strain L4-6T was mostly closely related to D. soli JS12-10T (98.73 %) and Dyella lipolytica DHOB07T (98.02 %). DNA–DNA hybridization data indicated that strain L4-6T represented a novel genomic species belonging to the genus Dyella . The polyphasic taxonomic characteristics indicated that the strain L4-6T represents a novel species of the genus Dyella , for which the name Dyella tabacisoli sp. nov. (type strain L4-6T=CGMCC 1.16273T=KCTC 62035T) is proposed.

A novel Gram-stain-negative, rod-shaped, non-motile, yellowish bacterium, designated strain 1.3611T, was isolated from the wormcast of Eisenia foetida. The strain grew optimally at 30–37 ℃, at pH 7.0 and with 0–1.0 % (w/v) NaCl. Based on the results of 16S rRNA gene sequence and phylogenetic analyses, strain 1.3611T showed the highest degree of 16S rRNA gene sequence similarity to Sphingobacterium olei HAL-9T (97.0 %), followed by Sphingobacterium alkalisoli Y3L14T (95.8 %). The respiratory quinone of strain 1.3611T was menaquinone-7 (MK-7) and its major cellular fatty acids were iso-C15 : 0 (41.3 %), summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c, 22.1 %) and iso-C17 : 0 3-OH (16.2 %). The major polar lipids were sphingophospholipid, phosphatidylethanolamine, four unidentified glycolipids, two unidentified phospholipids and five unidentified polar lipids. The genomic DNA G+C content was 39.0 mol%. The digital DNA–DNA hybridization and average nucleotide identity values between the genomes of strain 1.3611T and S. olei HAL-9T were 37.9 and 88.9 %, respectively. According to the phenotypic and chemotaxonomic phylogenetic results, strain 1.3611T should represent a novel species of the genus Sphingobacterium , for which the name Sphingobacterium lumbrici sp. nov. is proposed, with strain 1.3611T (=KCTC 62980T=CCTCC AB 2018349T) as the type strain.

An aerobic, rod-shaped, Gram-stain-positive, actinobacterial strain, designated 1.0914T, was isolated from a stalactite sample collected from a cave located in Guizhou Province, southwest PR China. Based on 16S rRNA gene sequence analysis, strain 1.0914T shared highest similarities values with Nocardioides pelophilus CGMCC 4.7388T (97.7 %), Nocardioides immobilis CCTCC AB 2017083T (97.5 %) and Nocardioides silvaticus CCTCC AB 2018079T (97.3 %) and values lower than 97.0 % to other members of the genus Nocardioides . Phylogenetic trees based on 16S rRNA gene sequences indicated that strain 1.0914T formed an isolated branch with N. pelophilus CGMCC 4.7388T, N. immobilis CCTCC AB 2017083T and N. silvaticus CCTCC AB 2018079T. The polar lipids contained phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol and one unidentified phospholipid in the cellular membrane. The major fatty acids were identified as iso-C16 : 0, C18 : 1 ω9c, C17 : 1 ω8c and C16 : 0. The predominant respiratory quinone was MK-8(H4) and ll-diaminopimelic acid was the diagnostic diamino acid in the cell-wall peptidoglycan. The genomic DNA G+C content was 71.1 mol%. The orthologous average nucleotide identiy values between N. pelophilus CGMCC 4.7388T, N. immobilis CCTCC AB 2017083T, N. silvaticus CCTCC 2018079T and strain 1.0914T were 82.3, 81.7 and 81.9 % respectively. DNA–DNA hybridization values between N. pelophilus CGMCC 4.7388T, N. immobilis CCTCC AB 2017083T, N. silvaticus CCTCC 2018079T and strain 1.0914T were 25.2, 24.6 and 24.5 % respectively. The phylogenetic, phenotypic and chemotaxonomic data supported the classification of strain 1.0914T as representing a new species of Nocardioides , for which the name Nocardioides stalactiti sp. nov. is proposed. The type strain is 1.0914T (=CCTCC AB 2018266T=KCTC 49243T).

A Gram-staining negative, facultative anaerobic, motile and short rod-shaped bacterium, designated strain yh7-1T, was isolated from rhizosphere soil of Citrus sinenesis collected from the garden of Citrus sinenesis in Ailao Mountain, south-west China. Cells grew at 15–45 °C, pH 5.0–9.0 and were able to tolerate up to 1% (w/v) NaCl on R2A medium. The respiratory lipoquinone was Q-10 and the major cellular fatty acids contained summed feature 8 (C18:1 ω7c or C18:1 ω6c) and C18:0. Polar lipids in the cellular membrane were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, two unidentified phospholipids and one unidentified aminophospholipid. The genomic DNA G+C content was 69.9 mol%. On basis of 16S rRNA gene sequence analysis, strain yh7-1T showed the highest similarities with Chthonobacter albigriseus KCTC 42450T (97.6%), Mongoliimonas terrestris KCTC 42635T (97.0%) and lower than 97.0% to other species. Phylogenetic trees based on 16S rRNA gene sequences indicated that strain yh7-1T clustered with C. albigriseus KCTC 42450T. The ANI values ranged between 78.1 and 82.7% for C. albigriseus KCTC 42450T, M. terrestris KCTC 42635T and strain yh7-1T, which were lower than the prokaryotic species delineation threshold of 95.0–96.0%. The digital DNA–DNA hybridization values between C. albigriseus KCTC 42450T, M. terrestris KCTC 42635T and strain yh7-1T indicated that the new isolate represents a novel genomic species. According to the phenotypic and genotypic characteristics, strain yh7-1T should belong to the genus Chthonobacter, for which the name Chthonobacter rhizosphaerae sp. nov. (type strain yh7-1T = CGMCC 1.17236T = CCTCC AB 2019258T = KCTC 82185T) is proposed.

Tobacco bacterial wilt (TBW) and tobacco black shank (TBS) are two of the most devastating tobacco soil-borne diseases worldwide. In this study, Pseudomonas aeruginosa NXHG29 exhibited dually antagonistic activities against TBW and TBS in vitro assays. Pot experiments were performed to evaluate the capability of a novel bio-organic fertilizer (BOF) consisting of organic fertilizer with NXHG29 to control TBW and TBS. The results showed that application of BOF could more effectively decrease the disease incidence of TBW and TBS than the direct application of NXHG29. Higher amounts of BOF application (0.5% and 1% amendment) resulted in the more suppressive effects on tested pathogens when compared with a low amount of BOF application (0.1% amendment). To determine the antagonistic mechanism of NXHG29, we investigated the colonization pattern of NXHG29 on tobacco roots in a sand system and a natural soil system by tagging NXHG29 with a GFP-marked plasmid. Similar observations were obtained in the two systems. The results indicated that GFP-tagged NXHG29 colonized first the differentiation zones followed by the elongation and maturation zones of the primary roots and subsequently around the junctions of primary and lateral roots. The population dynamics of GFP-tagged NXHG29 on tobacco roots and in the rhizosphere were also monitored. The development of the BOF using dually antagonistic bacteria might provide new options for control strategies, especially with respect to managing both diseases simultaneously in the host plant, which should be more effective in the long term.

A novel endophytic actinobacterium, designated strain EGI 6500139T, was isolated from the surface-sterilized roots of Anabasis aphylla L., collected from Xinjiang, northwest PR China, and subjected to polyphasic taxonomic characterization. Strain EGI 6500139T formed sparse aerial mycelium with rod-like spores. Whole-cell hydrolysates of the isolate contained meso-diaminopimelic acid as the cell-wall diamino acid, glucose as major sugar, and mannose, galactose, xylose and ribose as minor sugars. The polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside, one unidentified glycolipid, one unidentified phospholipid and four unidentified polar lipids. The major fatty acids identified were anteiso-C17 : 0, anteiso-C15 : 0, iso-C15 : 0 and iso-C16 : 0. The predominant menaquinones detected were MK-11 and MK-11(H2). The G+C content of the genomic DNA of strain EGI 6500139T was 70.4 mol%. Strain EGI 6500139T showed the highest 16S rRNA gene sequence similarity to Glycomyces lacisalsi XHU 5089T (96.3 %). Phylogenetic analysis showed that strain EGI 6500139T fell within the clade of the genus Glycomyces , and formed a clade with G. lacisalsi XHU 5089T and G. albus CCTCC AA 2013004T. Based on phenotypic, chemotaxonomic and phylogenetic data, strain EGI 6500139T represents a novel species of the genus Glycomyces , for which the name Glycomyces anabasis sp. nov. (type strain EGI 6500139T=JCM 30088T=KCTC 29495T) is proposed.

A Gram-stain-positive, alkaliphilic bacterium, designated EGI 80668T, was isolated from a Tamarix cone soil in Xinjiang, north-west China. Cells were facultatively anaerobic, terminal endospore-forming and motile by means of peritrichous flagella. Colonies were yellowish and the cells showed oxidase-negative and catalase-positive reactions. Strain EGI 80668T grew at pH 8.0–10.0 and with 0–10 % (w/v) NaCl (optimally at pH 9.0 and with 1–2 % NaCl) on marine agar 2216. The predominant menaquinone was MK-7. The major fatty acids were anteiso-C17 : 0 and anteiso-C15 : 0. The cellular polar lipids contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, four unknown phospholipids and one unknown aminophospholipid. The G+C content of the genomic DNA was 38.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain EGI 80668T was affiliated to the genus Bacillus . The highest 16S rRNA gene sequence similarity between strain EGI 80668T and a member of the genus Bacillus was 96.83 % with Bacillus cellulosilyticus JCM 9156T. A polyphasic taxonomic study based on morphological, physiological, biochemical and phylogenetic data indicated that strain EGI 80668T represents a novel species of the genus Bacillus , for which the name Bacillus tamaricis sp. nov. (type strain EGI 80668T=KCTC 33703T=CGMCC 1.15917T) is proposed.

A novel endophytic bacterium, designated strain EGI 6500252T, was isolated from the surface-sterilized roots of a medicinal plant (Capparis spinosa L.) collected from Urumqi city, Xinjiang, north-west China. Cells were Gram-stain-positive, non-motile, aerobic, catalase- and oxidase-positive, rod-shaped and did not display spore formation. Strain EGI 6500252T grew at 10–40 °C (optimum 25–30 °C), at pH 6.0–8.0 (optimum pH 7.0) and in the presence of 0–10 % (w/v) NaCl (optimum 0–3 %). The major cellular fatty acids (>10 %) were identified as iso-C15 : 0, anteiso-C15 : 0, anteiso-C17 : 0 and summed feature 4. The predominant polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, four unknown phospholipids, one unknown glycolipid and one unknown lipid. The dominant isoprenoid quinone was menaquinone 7 (MK-7). The DNA G+C content was 39.9 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain EGI 6500252T belonged to the genus Bacillus , and exhibited a highest 16S rRNA gene sequence similarity (96.2 %) that was lower than the suggested threshold (97.0 %) for separating bacterial species. On the basis of the phylogenetic analysis, chemotaxonomic data and physiological characteristics, strain EGI 6500252T represents a novel species of the genus Bacillus , for which the name Bacillus capparidis sp. nov. is proposed. The type strain is EGI 6500252T (=CGMCC 1.12820T=KCTC 33514T).

An orange-coloured, aerobic, motile, short-rod-shaped bacterial strain, designated EGI 6500337T, was isolated from the surface-sterilized root of a halophyte, Anabasis elatior (C. A. Mey.) Schischk, collected from Urumqi, Xinjiang province, north-west China. Growth occurred at 5-35 °C (optimum 30 °C), at pH 6.0-9.0 (optimum pH 7.0) and in the presence of 0-6 % (w/v) NaCl (optimum 0-1 %). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain EGI 6500337T formed a distinct lineage in the cluster that comprised the genera Aurantimonas and Aureimonas in the family Aurantimonadaceae. The 16S rRNA gene sequence of strain EGI 6500337T shared highest similarity with those of Aurantimonas coralicida DSM 14790T (97.15 %) and Aurantimonas manganoxydans DSM 21871T (97.15 %). Strain EGI 6500337T contained Q-10 as the dominant isoprenoid quinone. The major cellular fatty acids were C18 : 1ω7c and C19 : 0ω8c cyclo. The polar lipid profile of strain EGI 6500337T contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine and phosphatidylethanolamine as major components, similarly to members of the genus Aurantimonas. The DNA G+C content of strain EGI 6500337T was 66.8 mol%. The level of DNA-DNA relatedness between strain EGI 6500337T and Aurantimonas coralicida DSM 14790T was 24.7±2.9 %. On the basis of the phylogenetic analysis, chemotaxonomic data and phenotypic characteristics, strain EGI 6500337T represents a novel species of the genus Aurantimonas, for which the name Aurantimonas endophytica sp. nov. is proposed. The type strain is EGI 6500337T (=KCTC 52296T=CPCC 100904T).

A Gram-stain-negative, aerobic, non-motile and rod-shaped bacterium, designated strain X7XT, was isolated from a rhizosphere soil sample of Nicotiana tabacum L. collected from a tobacco factory located in Kunming, south-western China. The cells showed oxidase-positive and catalase-positive reactions. Growth occurred at 20–40 °C and pH 6.0–8.0, with optimal growth at 30 °C and pH 7.0. The predominant respiratory quinone was MK-7. The major fatty acids were identified as iso-C15 : 0, iso-C17 : 0 3OH and summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c). The cellular polar lipids contained phosphatidylethanolamine, an unidentified aminophospholipid, two unidentified glycolipids, four unidentified aminolipids and four unidentified lipids. The genomic DNA G+C content was 49.7 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain X7XT should be affiliated to the genus Flavisolibacter . Results from further analysis showed that strain X7XT had highest 16S rRNA gene sequence similarity to Flavisolibacter metallilatus TX0661T (96.4 %) and ‘ Flavisolibacter swuensis ’ SR2-4-2T (96.4 %), followed by other species of the genus Flavisolibacter . The polyphasic taxonomic characteristics indicated that strain X7XT represents a novel species of the genus Flavisolibacter , for which the name Flavisolibacter nicotianae sp. nov. (type strain X7XT=KCTC 62326T=CGMCC 16451T) is proposed.

An arsenic-resistant strain, CB3T, was isolated from arsenic-rich aquifers at the Jianghan Plain in Hubei, China. Phylogenetic and biochemical analysis suggested that it should represent a new species of the genus Pseudaminobacter in the family Phyllobacteriaceae. The 16S rRNA gene of CB3T shared the highest sequence similarities to those of the type strains Pseudaminobacter defluvii THI 051T (97.8 % identity) and Pseudaminobacter salicylatoxidans BN12T (97.4 %). The DNA–DNA relatedness values of CB3T with respect to strains belonging to the genus Pseudaminobacter were less than 70 %. The fatty acid profile of CB3T consisted of C16 : 0, cyclo-C19 : 0 ω8c and summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c) as major components. The major polar lipids were phosphatidylcholine, phosphatidylglycerol, phosphatidyldimethylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylethanolamine and diphosphatidylglycerol. The DNA G+C content was 61.4 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain CB3T was distinct from previously described Pseudaminobacter species. Therefore, we propose that strain CB3T represents a novel species of the genus Pseudaminobacter, Pseudaminobacter arsenicus sp. nov., strain CB3T (=CCTCC AB2016116T=KCTC 52625T) is designated as the type strain.

A Gram-stain-negative, aerobic, rod-shaped bacterium, designated strain C8-1T, was isolated from the rhizosphere soil of Nicotiana tabacum L. collected from Kunming, south-west China. The cells showed oxidase-positive and catalase-positive reactions. Growth was observed at 10–40 °C, at pH 6.0–8.0 and in the presence of up to 1 % (w/v) NaCl, with optimal growth at 30 °C and pH 7.0. The predominant isoprenoid quinone was Q-8. The major fatty acids were identified as iso-C15 : 0, iso-C17 : 0 and iso-C17 : 1ω9c. The cellular polar lipids contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylmethylethanolamine, five unidentified phospholipids and two unidentified aminophospholipids. The genomic DNA G+C content was 70.7 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain C8-1T should be assigned to the genus Lysobacter . 16S rRNA gene sequence similarity analysis showed that strain C8-1T was closely related to Lysobacter cavernae YIM C01544T (98.6 %), Lysobacter soli DCY21T (97.6 %), Lysobacter panacisoli CJ29T (97.3 %), Lysobacter firmicutimachus PB-6250T (97.3 %), Lysobacter niastensis GH41-7T (97.3 %) and Lysobacter gummosus KCTC 12132T (97.1 %). DNA–DNA hybridization data indicated that the isolate may represent a novel genomic species belonging to the genus Lysobacter . Polyphasic taxonomic characteristics indicated that strain C8-1T represents a novel species of the genus Lysobacter , for which the name Lysobacter tabacisoli sp. nov. is proposed. The type strain is C8-1T (=KCTC 62034T=CGMCC 1.16271T) .

A Gram-staining-negative, non-motile and rod-shaped bacterium, designated strain h337T, was isolated from an arable soil sample of a tobacco field in Kunming, south-west China. The cells showed oxidase-positive and catalase-positive reactions. Growth was observed at 10–35 °C, at pH 6.0–9.0 and in the presence of up to 3 % (w/v) NaCl, with optimal growth at 30 °C, pH 7.0 and with 1–2 % (w/v) NaCl. The predominant isoprenoid quinone was MK-7. The major fatty acids were identified as iso-C15 : 0, iso-C17 : 0 3-OH, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and summed feature 4 (iso-C17 : 1 I and/or anteiso-C17 : 1 B). The cellular polar lipids contained phosphatidylethanolamine, sphingophospholipid, four unidentified phospholipids, five unidentified lipids and three unidentified aminophospholipids. The genomic DNA G+C content was 41.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain h337T should be assigned to the genus Sphingobacterium . 16S rRNA gene sequence similarity analysis showed that strain h337T was most closely related to ‘ Sphingobacterium yamdrokense ’ 3-0-1 (98.8 %) and Sphingobacterium yanglingense CCNWSP36-1T (98.5 %) and shared less than 97 % similarity with other species of the genus Sphingobacterium . DNA–DNA hybridization data indicated that the isolate represented a novel genomic species belonging to the genus Sphingobacterium . The characteristics determined in this polyphasic taxonomic study indicated that strain h337T represents a novel species of the genus Sphingobacterium , for which the name Sphingobacterium tabacisoli sp. nov. (type strain h337T=KCTC 52298T=CCTCC AB 2017155T) is proposed.

A Gram-stain negative, motile, rod-shaped bacterium, designated strain YIM Hb-3(T), was isolated from the stem of a tobacco plant. The strain was observed to form convex, circular and yellow-colored colonies. The predominant respiratory quinone was identified as Q-8. The major fatty acids (>5%) detected were C(16:1)ω7c and/or C(16:1)ω6c (summed feature 3), C(16:0), C(17:0)cyclo, C(18:1)ω7c and/or C(18:1)ω6c (summed feature 8), C(14:0)3-OH and/or iso-C(16:1)I (summed feature 2), C(14:0) and C(12:0). The genomic DNA G+C content was determined to be 54.8 mol%. Phylogenetic trees based on 16S rRNA gene sequences and multilocus sequence analysis showed that strain YIM Hb-3(T) had the closest phylogenetic relationship with Enterobacter mori LMG 25706(T). DNA-DNA relatedness value between strain YIM Hb-3(T) and E. mori LMG 25706(T) was 46.9 ± 3.8%. On the basis of phenotypic and chemotaxonomic data, phylogenetic analysis, and DNA-DNA relatedness value, strain YIM Hb-3(T) is considered to represent a novel species of the genus Enterobacter, for which the name Enterobacter tabaci sp. nov. is proposed. The type strain is YIM Hb-3(T) (=KACC 17832(T) =KCTC 42694(T)).

Accumulated evidence suggests that root exudates have a major role in mediating plant–microbe interactions in the rhizosphere. Here, we characterized tobacco root exudates (TREs) by GC–MS and nicotine, scopoletin, and octadecane were identified as three main components of TREs. Qualitative and quantitative chemotaxis assays revealed that Pseudomonas aeruginosa NXHG29 with antagonistic activity displayed positive chemotactic responses towards TREs and their three main components (nicotine, scopoletin, octadecane) and its enhanced chemotaxis were induced by these substances in a concentration-dependent manner. Furthermore, following GC–MS and chemotaxis analysis, nicotine was selected as the target for evaluation of the effect on NXHG29 regarding antagonism, growth, root colonization and biocontrol efficiency. Results of in vitro studies showed that nicotine as a sole carbon source could enhance growth of NXHG29 and significantly increased the antagonism of NXHG29. We also demonstrated that nicotine exerted enhancing effects on the colonization ability of NXHG29 on tobacco roots by combining CLSM observations with investigation of population level dynamics by selective dilution plating method. Results from greenhouse experiments suggested nicotine exhibited stimulatory effects on the biocontrol efficiency of NXHG29 against bacterial wilt and black shank on tobacco. The stimulatory effect of nicotine was affected by the concentration and timing of nicotine application and further supported by the results of population level of NXHG29 on tobacco roots. This is the first report on the enhancement effect of nicotine from TREs on an antagonistic bacterium for its root colonization, control of soil-borne pathogens, regarding the chemotaxis and in vitro antagonism and growth.

A novel endophytic actinobacterial strain, designated EGI 6500195T, was isolated from fruits of Capparis spinosa. Growth occurred at 10–45 °C (optimum 30 °C), at pH 6–8 (optimum pH 7) and in the presence of 0–1 % (w/v) NaCl. Strain EGI 6500195T shared highest 16S rRNA gene sequence similarity (97.74 %) with Streptomyces vitaminophilus DSM 41686T and less than 97 % sequence similarity with other members of the genus Streptomyces . The diagnostic amino acid in the peptidoglycan was ll-diaminopimelic acid. Whole-cell hydrolysates contained glucose, ribose, fructose and mannose. The predominant menaquinones were MK-9(H6) and MK-9(H8). The polar lipid profile of strain EGI 6500195T included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylinositol, phosphatidylcholine, three unknown phospholipids, an unknown aminophospholipid and an unknown aminolipid. The cellular fatty acids were anteiso-C15 : 0, anteiso-C17 : 0, iso-C15 : 0, iso-C16 : 0, anteiso-C17 : 1 ω9c, summed feature 4 (iso-C17 : 1 I and/or anteiso-C17 : 1 B) and iso-C17 : 1 ω9c. The DNA G+C content of strain EGI 6500195T was 74.1 mol%. The level of DNA–DNA relatedness between strain EGI 6500195T and Streptomyces. vitaminophilus DSM 41686T was 14.1±3.5 %. On the basis of the phenotypic, phylogenetic, chemotaxonomic and DNA–DNA hybridization data, strain EGI 6500195T represents a novel species of the genus Streptomyces , for which the name Streptomyces capparidis sp. nov. is proposed. The type strain is EGI 6500195T (=DSM 42145T=JCM 30089T).

An alkaliphilic and halophilic actinomycete strain, designated EGI 80537T, was isolated from a saline-alkali soil sample of Xinjiang, north-west China and subjected to a taxonomic characterization using a polyphasic approach. Strain EGI 80537T formed reticulate long aerial hyphae. Whole-cell hydrolysates of the isolate contained meso-diaminopimelic acid as the cell-wall diamino acid and mannose as the diagnostic sugar. The major fatty acids identified were iso-C16 : 0, anteiso-C17 : 0 and 10-methyl-C18 : 0 (TBSA). The predominant menaquinones detected were MK-10(H8) and MK-10(H6). The G+C content of the genomic DNA of strain EGI 80537T was 67.6 mol%. Strain EGI 80537T showed the highest 16S rRNA gene sequence similarity to Allosalinactinospora lopnorensis CA15-2T (96.7 %). Phylogenetic analysis showed that strain EGI 80537T clustered with the members of the family Nocardiopsaceae. Based on phenotypic, chemotaxonomic and phylogenetic characteristics, strain EGI 80537T represents a novel species of a new genus in the family Nocardiopsaceae, for which the name Lipingzhangella halophila gen. nov., sp. nov. is proposed. The type strain of the type species is EGI 80537T(=CGMCC 4.7224T= DSM 102030T).

An alkaliphilic, filamentous actinomycete, designated EGI 80629T, was isolated from a soil sample of Xinjiang, north-west China. Strain EGI 80629T grew at pH 6.0–11.0 (optimum pH 9.0–10.0) and in the presence of 0–13.0 % NaCl (optimum 3.0–5.0 %). The isolate formed fragmented substrate mycelia, and aerial hyphae with short spore chains with rod-like spores. Whole-cell hydrolysates of the isolate contained ll-diaminopimelic acid as the diagnostic diamino acid, and mannose and rhamnose as diagnostic sugars. The major fatty acids identified were iso-C15 : 0, iso-C16 : 0, anteiso-C15 : 0 and iso-C17 : 0. The predominant menaquinone was MK-9(H4), while the polar lipids were diphosphatidylglycerol, phosphatidylglycerol, two phosphatidylinositol mannosides, five unknown phospholipids, three unknown phosphoglycolipids, one unknown glycolipid, four unknown polar lipids and one unknown aminophospholipid. The G+C content of the genomic DNA was 67.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain EGI 80629T clustered with the genus Phytoactinopolyspora. The 16S rRNA gene sequence similarity between strain EGI 80629T and Phytoactinopolyspora endophytica EGI 60009T was 96.8 %. Based on morphological, chemotaxonomic and phylogenetic characteristics, strain EGI 80629T represents a novel species of the genus Phytoactinopolyspora, for which the name Phytoactinopolyspora alkaliphila sp. nov. is proposed. The type strain is EGI 80629T ( = CGMCC 4.7225T = KCTC 39701T).

A Gram-staining negative, aerobic, rod-shaped bacterium, designated YIM C01544(T), was isolated from a soil sample collected from Sigangli Cave, Yunnan province, South-West China. The strain was able to grow over a range of temperatures (4-30 °C), pH (6.0-10.0) and NaCl concentration (0-2 %, w/v). Comparative 16S rRNA gene sequence analysis revealed that strain YIM C01544(T) should be a member of the genus Lysobacter. The strain is closely related to Lysobacter niastensis GH41-7(T) (97.6 %), Lysobacter soli DCY21(T) (97.5 %), Lysobacter enzymogenes DSM 2043(T) (97.3 %), Lysobacter antibioticus DSM 2044(T) (97.1 %) and Lysobacter panacisoli CJ29(T) (97.1 %). The genomic DNA relatedness values (

A novel obligately halophilic, facultatively alkaliphilic actinobacterium, designated EGI 80759T, was isolated from the rhizosphere of Tamarix hispida Willd, Karamay, Xinjiang province, north-west China. Cells of strain EGI 80759T were Gram-stain-positive, non-motile and non-endospore-forming rods. Strain EGI 80759T showed obligately halophilic growth with a tolerance to 8–25 % (w/v) NaCl (optimum growth at 10–12 %, w/v) and facultatively alkaliphilic growth within the pH range 7.0–11.0 (optimum growth at pH 9.0–10.0). Cell-wall hydrolysates of the isolate contained meso-diaminopimelic acid (peptidoglycan type A1γ), with glucose, glucosamine, ribose and mannose as the major sugars. The major fatty acids identified were 10-methyl-C17 : 0, C17 : 1ω8c and C17 : 0. The predominant menaquinone was MK-9(H4). The G+C content of the genomic DNA was 72.1 mol%. Phylogenetic analysis, based on 16S rRNA gene sequences, revealed that strain EGI 80759T clustered with members of the class Nitriliruptoria and showed highest 16S rRNA gene sequence similarities with Euzebya tangerina F10T (90.3 %) and Nitriliruptor alkaliphilus ANL-iso2T (88.1 %). On the basis of the data obtained from phenotypic and chemotaxonomic studies and the phylogenetic analysis, the isolate is proposed to be a representative of a novel genus and a novel species, Egibacter rhizosphaerae gen. nov., sp. nov., of a proposed novel family, Egibacteraceae fam. nov., and order, Egibacterales ord. nov., within the class Nitriliruptoria. The type strain of the type species, Egibacter rhizosphaerae, is EGI 80759T ( = CGMCC 1.14997T = KCTC 39588T).

A Gram-staining-positive, white-coloured, aerobic, non-motile, catalase-positive and oxidase-negative, endophytic actinobacterium, designated strain EGI 6500322T, was isolated from the surface-sterilized root of the halophyte Salsola affinis C. A. Mey collected from Urumqi, Xinjiang province, north-west China. Growth occurred at 5–35 °C (optimum 25–30 °C), at pH 5–10 (optimum pH 7–8) and with 0–13 % NaCl (w/v) (optimum 0–5 %). The predominant menaquinone was MK-9 (93.1 %). The major cellular fatty acids were anteiso-C15:0 (49.5 %) and iso-C15:0 (15.1 %). The cell-wall peptidoglycan contained lysine, alanine and glutamic acid. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, two unknown phospholipids and one unknown glycolipid. The DNA G+C content of strain EGI 6500322T was 62.0 mol%. Based on 16S rRNA gene sequence analysis, the nearest phylogenetic neighbours of strain EGI 6500322T were identified as Arthrobacter ardleyensis DSM 17432T (98.38 %) and Arthrobacter bergerei DSM 16367T (98.37 %). The DNA–DNA relatedness between strain EGI 6500322T and Arthrobacter ardleyensis DSM 17432T and Arthrobacter bergerei DSM 16367T was 53.4 ± 4.1 % and 30.5 ± 1.7 %, respectively. On the basis of the phylogenetic analysis, chemotaxonomic data, physiological characteristics and DNA–DNA hybridization data, strain EGI 6500322T should represent a novel species of the genus Arthrobacter, for which the name Arthrobacter endophyticus sp. nov. is proposed. The type strain is EGI 6500322T ( = KCTC 29490T = JCM 30091T).

A Gram-stain positive, facultative anaerobic endospore-forming bacterium, designated strain YIM h-19(T), was isolated from a tobacco sample. Cells were observed to be motile rods by means of peritrichous flagella and colonies were observed to be convex, yellow, circular and showed catalase-positive and oxidase-negative reactions. Strain YIM h-19(T) was able to grow at 4-45 °C, pH 6.0-8.0 and 0-3 % NaCl (w/v). The predominant respiratory quinone was identified as MK-7. Major fatty acids were identified as anteiso-C15:0, anteiso-C17:0 and C16:0. The polar lipids were found to be phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol and two unidentified polar lipids. The genomic DNA G+C content was determined to be 54 mol%. 16S rRNA gene sequence analysis showed the strain YIM h-19(T) was most closely related to Paenibacillus hordei RH-N24(T) and Paenibacillus hunanensis FeL05(T) with similarities of 98.30 and 94.64 % respectively. However, DNA-DNA hybridization data indicated that the isolate represented a novel genomic species with the genus Paenibacillus. All data from genotypic and phenotypic analyses support the conclusion that strain YIM h-19(T) represents a novel species of the genus Paenibacillus, for which the name Paenibacillus nicotianae sp. nov. is proposed. The type strain is YIM h-19(T) (=CGMCC1.12819(T) = NRRL B-59112(T)).