First report of Cigar Tobacco Root Rot Caused by Setophoma terrestris in China.

Cigar tobacco (Nicotiana tabacum L.) is widely planted in Yunnan, which is becoming an important economic crop in China. In March 2023, root rot of cigar tobacco (cv. Yunxue 38) was observed in Baoshan (98°51'E, 24°58'N), and in July 2022 root rot of tobacco (cv. Yunyan 87) was observed in Dali (99°54'E, 26°30'N), Yunnan Province, China. The average disease incidences surveyed in the fields reached 10%. At the early stage, the bottom leaves showed wilting and turned yellow, and the roots became brown. Following the disease development, the color of roots turned to dark brown and ultimately necrosis. To isolate the causal agent, small pieces (5×5 mm) of diseased root from 6 symptomatic plant samples (three samples of cv. Yunxue 38 and three samples of cv. Yunyan 87) were cut. Pieces were surface-sterilized by dipping in 75% ethanol for 30 s, rinsed three times with sterile distilled water, then transferred to potato dextrose agar (PDA) medium and incubated at 28°C in the dark. Six fungal isolates cultured for 14 days were obtained. They were morphologically similar, so a representative isolate was selected for the following experiment. The colonies grew slowly on PDA, and their color were light pink initially, then changed to amaranth. Hyphae were hyaline and septate. Microconidia were hardly produced on PDA plates. After 14 days of culture on V8 juice agar, the colonies showed white aerial mycelia, and ellipsoidal and transparent conidia were observed, which measured 6.5 to 8.3 × 3.4 to 5.0 µm (n=20). Also, the pycnidia were measured 150 to 220 µm, that were subglobose in dark brown with brown setae. These morphological characteristics of 22DL91 were identical to S. terrestris (Boerema et al. 2004). For molecular identification, DNA was extracted and the PCR products of ITS region and polymerase II second largest subunit (RPB2), amplified with the primers ITS1/ITS4 and RPB2-5F/RPB2-7cR, were sequenced. By BLASTn analysis, the obtained ITS sequences showed 100% homology and the RPB2 sequences showed 95% homology with S. terrestris strains in GenBank (accession ON006851 and OM417590). The sequences were deposited in NCBI with accession numbers OR539491 (ITS) and OR554276 (RPB2), respectively. Based on the morphology and phylogenetic analysis, the isolate was 22DL91 identified as S. terrestris. Pathogenicity was evaluated on 50-day-old cigar tobacco seedlings (cv. Yunxue 38) and tobacco seedlings (cv. Yunyan 87). Ten plants were inoculated with 20 mL of conidial suspension of 105 conidia/mL poured onto the roots and ten control seedlings dipped in sterile water as controls (Luo et al. 2023). After 14 days, all inoculated seedlings showed the symptoms with leaves yellowing and root rot, whereas the control seedlings had no symptoms. Moreover, the fungus S. terrestris was reisolated from the infected roots, fulfilling Koch's postulates. This fungus was previously known to cause pink root on garlic in China (Zhang et al. 2019). To our knowledge, this is the first report of S. terrestris causing root rot of Nicotiana tabacum in China. Therefore, this finding will provide valuable information for prevention and management of root rot on tobacco.

First report of Tobacco Fusarium Root Rot Caused by Fusarium meridionale in China.

Tobacco (Nicotiana tabacum L.) was an important economic crop in China. A survey in Yunnan Province in the last several years showed that the incidence of tobacco root rot was 3 to 30%. In July 2021, root rot symptoms were observed with an average incidence of 5% on tobacco (cultivar Yunyan 87) in Dali (25.61° N, 100.27° E). Typical disease symptoms included plants stunted at early stages, brown-colored withering lower leaves and roots that became brown. Under high humidity conditions, symptoms of rot expanded in the roots, also the whole plant became wilted and stunted, and some plants ultimately died. Infected pieces of stem tissues and root were dissected and then sterilized with 2% NaOCl for 30 s, rinsed three times with sterile distilled water, and dried with sterilized filter paper. Three pieces were plated onto potato dextrose agar (PDA) for 3 days at 25°C with a 12-h light period. Colonies on PDA were characterized by white to pale yellow flocculent aerial mycelium, and a pink to red pigment in the agar. To induce sporulation, mycelium on PDA was transferred to carnation leaf agar (CLA) medium. After incubation for 7 days, a single spore was isolated from representative isolate 21DL16 for morphological and molecular analyses. Macroconidia observed on CLA were falcate, slightly curved, three to five septate, measured 33.1 to 53.7 × 3.2 to 4.6 µm (n=50), with a typical foot shaped basal cell. Morphological characteristics of the fungus were in agreement with the description of Fusarium graminearum (Leslie and Summerell 2006). For further identification, the internal transcribed spacer (ITS) region rDNA, translation elongation factor 1ɑ (EF-1α) and RNA polymerase II second largest subunit (RPB2) gene were amplified and sequenced using primers ITS1/ITS4 (White et al. 1990), EF1/EF2 (O'Donnell et al. 2015) and RPB2-5F/RPB2-7cR (Reeb et al. 2004), respectively. Although the ITS sequence (GenBank accession no. OM392025) cannot distinguish F. meridionale from F. graminearum, combined phylogenetic analysis of the sequence of TEF1 (ON062055) and RPB2 (ON211932) clearly showed that the pathogen is F. meridionale that the sequences were 100% similarity, 0.0e-value and 100% query coverage to F. meridionale. Pathogenicity studies were conducted on six-leaf-stage tobacco seedlings cultivar Yunyan 87. A conidial suspension (1×105 spores/mL) was poured over the roots of tobacco seedlings. Three seedlings were treated with sterile water that served as controls. All 10 seedlings were maintained at 25°C at 70% relative humidity. After 5 days, the lower leaves showed symptoms of wilting and the roots of all inoculated seedlings become discolored, that were similar with the original symptoms, whereas the control seedlings did not develop symptoms. The fungus reisolated from the inoculated seedlings was identical to F. meridionale using the EF-1α gene sequence. To date, Fusarium root rot on tobacco in China was caused by F. oxysporium (Chen 2013). However, to the best of our knowledge, this is the first report of F. meridionale causing root rot on tobacco in China. Identification of F. meridionale as a root rot agent might provide important insight for disease management practices on tobacco caused by Fusarium species.

Pseudomonas lijiangensis sp. nov., a novel phytopathogenic bacterium isolated from black spots of tobacco.

Three Gram-stain-negative, motile, with amphilophotrichous flagella, and rod-shaped bacteria (LJ1, LJ2T and LJ3) were isolated from lower leaves with black spots on flue-cured tobacco in Yunnan, PR China. The results of phylogenetic analysis based on 16S rRNA gene sequences indicate that all the strains from tobacco were closely related to the type strains of the Pseudomonas syringae group within the P. fluorescens lineage and LJ2T has the highest sequence identities with P. cichorii DSM 50259T (99.92 %), P. capsici Pc19-1T (99.67 %) and P. ovata F51T (98.94 %) . The 16S rRNA gene sequence identities between LJ2T and other members of the genus Pseudomonas were below 98.50%. The average nucleotide identity by blast (ANIb) values between LJ2T and P. cichorii DSM 50259T, P. capsici Pc19-1T and P. ovata F51T were less than 95 %, and the in silico DNA-DNA hybridization (isDDH) values (yielded by formula 2) were less than 70 %. The major fatty acids were C16  :  1ω7c and/or C16  :  1ω6c (summed feature 3), C16  :  0 and C18  :  1ω7c and/or C18  :  1ω6c (summed feature 8). The polar lipids profile of LJ2T consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, two unidentified phospholipids and one unidentified glycolipid. The predominant respiratory quinone was Q-9. The DNA G+C content of LJ2T was 58.4 mol%. On the basis of these data, we concluded that LJ2T represents a novel species of the genus Pseudomonas, for which the name Pseudomonas lijiangensis sp. nov. is proposed. The type strain of Pseudomonas lijiangensis sp. nov. is LJ2T (=CCTCC AB 2021465T=GDMCC 1.2884T=JCM 35177T).

Ralstonia wenshanensis sp. nov., a novel bacterium isolated from a tobacco field in Yunnan, China.

A Gram-negative, aerobic, motile with paired polar flagella and rod-shaped bacterium strain (56D2T) was isolated from tobacco planting soil in Yunnan, PR China. Major fatty acids were C16  :  1 ω7c (summed feature 3), C16  :  0 and C18  :  1 ω7c (summed feature 8). The polar lipid profile of strain 56D2T consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, one unidentified aminophospholipid and one unidentified glycolipid. Moreover, strain 56D2T contained ubiquinone Q-8 as the sole respiratory quinone. 16S rRNA gene sequence analysis showed that strain 56D2T was closely related to members of the genus Ralstonia and the two type strains with the highest sequence identities were R. mannitolilytica LMG 6866T (98.36 %) and R. pickettii K-288T (98.22 %). The 16S rRNA gene sequence identities between strain 56D2T and other members of the genus Ralstonia were below 98.00 %. Genome sequencing revealed a genome size of 5.87 Mb and a G+C content of 63.7 mol%. The average nucleotide identity values between strain 56D2T and R. pickettii K-288T, R. mannitolilytica LMG 6866 T and R. insidiosa CCUG 46789T were less than 95 %, and the in silico DNA-DNA hybridization values (yielded by formula 2) were less than 70 %. Based on these data, we conclude that strain 56D2T represents a novel species of the genus Ralstonia, for which the name Ralstonia wenshanensis sp. nov. is proposed. The type strain of Ralstonia wenshanensis sp. nov. is 56D2T (=CCTCC AB 2021466T=GDMCC 1.2886T=JCM 35178T).

First Report of Pectobacterium versatile Causing Stem Rot of Tobacco in China.

Tobacco is one of the most significant non-food cash crops (Lu et al. 2020). In March 2022, cigar tobacco plants showing characteristic symptoms of vascular discoloration, stem rotting, leaf wilting and rotting were observed in Tengchong city (N 25°3'26″, E 98°25'6″) of Yunnan province, China (Fig. S1). The disease incidence was about 5% on cultivar Yunxue 6 in a 33-ha field. Infected stems were collected from Tengchong for pathogen isolation and 16S rDNA sequence analysis was performed as previously described (Lu et al. 2021). Sequence analysis showed that tobacco isolates (GenBank accession numbers: ON795108, ON795107 and ON795106) had an identical sequence with that of the species type strain of Pectobacterium versatile CFBP 6051T and shared the sequence identities of 99.55% and 99.47% with P. carotovorum DSM 30168T and P. parvum s0421T, respectively. Furthermore, phylogenetic analysis showed that tobacco strains were clustered with Pectobacterium versatile CFBP 6051T (Fig. S2a). In API assays, strain 22TC1 was positive for ß-galactosidase activity, reduction of nitrates to nitrites, fermentation of glucose, hydrolysis of esculin and gelatin, assimilation of D-glucose, L-arabinose, D-mannose, D-mannitol, N-acetylglucosamine, malic acid and trisodium citrate; positive for the enzymatic substrates of alkaline phosphatase, leucine arylamidase, acid phosphatase, naphthol-AS-BI-phosphohydrolase, α-galactosidase, ß-galactosidase and α-glucosidase. Furthermore, the average nucleotide identity (ANI) analysis (Richter et al. 2015) showed that strain 22TC1 (GenBank accession number: JAMWYQ000000000) had the highest ANIb score of 96.76% and ANIm value of 97.19% with P. versatile CFBP 6051T. Similarly, in silico DNA-DNA hybridization (isDDH) value was 74.5% compared to P. versatile CFBP 6051T, isDDH values were 35.5-63.7% with the other Pectobacterium species, which below the 70% threshold value for species delineation (Meier-Kolthoff et al. 2021). The phylogenomic analysis also showed that strain 22TC1 was clustered with the species type strain of P. versatile CFBP 6051T. For pathogenicity tests, cell suspension with ten-fold dilution (approx. 1 x 108 CFU/ml) was injected into the leaf axils of two 2-month-old tobacco stems (cv. Yunyan 87). As a control, tobacco seedlings were inoculated with sterile distilled water. The plants were sealed in plastic bags and maintained in a growth chamber at 28°C for 2 d. The symptoms of water-soaked decay were observed within 24 h of inoculation. Whole-plant decay was at 2 days after injection. No symptoms were developed in the controls. Reisolation was performed on diseased stems and the identity of isolated bacteria was confirmed by PCR and sequencing of 16S rRNA. Similar results were obtained in two independent experiments. Based on the above-described data, the causal pathogen of stem rot on cigar tobacco in Tengchong was identified as P. versatile. To our knowledge, this is the first time that P. versatile is found to cause stem rot on tobacco. Pectobacterium species have been reported to cause seed-borne diseases on tobacco seedlings in the floating tray system and soil-borne diseases in tobacco fields (Wang et al. 2017; Xia and Mo 2007). Therefore, studying the possible transmission of the P. versatile to tobacco plants is necessary.

Complete Genome Sequence of Ralstonia syzygii subsp. indonesiensis Strain LLRS-1, Isolated from Wilted Tobacco in China.

Here, we present the complete genome sequence and annotation of Ralstonia syzygii subsp. indonesiensis strain LLRS-1, which caused bacterial wilt on flue-cured tobacco in Yunnan Province, southwest China. Strain LLRS-1 is the first R. syzygii strain identified to be pathogenic to tobacco in China. The completely assembled genome of strain LLRS-1 consists of a 3,648,314-bp circular chromosome and a 2,046,405-bp megaplasmid with 5,190 protein-coding genes, 55 transfer RNAs, 28 small RNAs, 3 structural RNAs (5S, 16S, and 23S), and a G+C content of 67.05%.

A novel putative betapartitivirus isolated from the plant-pathogenic fungus Rhizoctonia solani.

In this study, we describe the genome sequence of a novel double-stranded RNA (dsRNA) mycovirus, designated as "Rhizoctonia solani partitivirus 15" (RsPV15), from the phytopathogenic fungus Rhizoctonia solani. RsPV15 consists of two genomic double-stranded RNA segments, dsRNA-1 and dsRNA-2, which are 2433 bp and 2350 bp long, respectively. Each of the dsRNA segments contains a single open reading frame, encoding the putative RNA-dependent RNA polymerase and coat protein, respectively. Homology searches and phylogenetic analysis suggested that RsPV15 is a new member of the genus Betapartitivirus within the family Partitiviridae.

Biodegradation of the Herbicide 2,4-Dichlorophenoxyacetic Acid by a New Isolated Strain of Achromobacter sp. LZ35.

In this study, a bacterial strain of Achromobacter sp. LZ35, which was capable of utilizing 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-methyl-4-chlorophenoxy acetic acid (MCPA) as the sole sources of carbon and energy for growth, was isolated from the soil in a disused pesticide factory in Suzhou, China. The optimal 2,4-D degradation by strain LZ35 occurred at 30 °C and pH 8.0 when the initial 2,4-D concentration was 200 mg L-1. Strain LZ35 harbored the conserved 2,4-D/alpha-ketoglutarate dioxygenase (96%) and 2,4-dichlorophenol hydroxylase (99%), and catabolized 2,4-D via the intermediate 2,4-dichlorophenol. The inoculation of 7.8 × 106 CFU g-1 soil of strain LZ35 cells to 2,4-D-contaminated soil could efficiently remove over 75 and 90% of 100 and 50 mg L-1 2,4-D in 12 days and significantly released the phytotoxicity of maize caused by the 2,4-D residue. This is the first report of an Achromobacter sp. strain that was capable of mineralizing both 2,4-D and MCPA. This study provides us a promising candidate for its application in the bioremediation of 2,4-D- or MCPA-contaminated sites.

Camelimonas fluminis sp. nov., a cyhalothrin-degrading bacterium isolated from river water.

An aerobic, Gram-stain-negative, short rod-shaped, non-spore-forming, cyhalothrin-degrading bacterial strain, XZ2(T), was isolated from the surface water of Hanjiang River in Wuhan, China. Strain XZ2(T) grew optimally at pH 6.0, 30 °C and in the absence of NaCl. The G+C content of the total DNA was 64.1 mol%. The 16S rRNA gene sequence of strain XZ2(T) showed the highest similarity to that of Camelimonas lactis M 2040(T) (99.1%), followed by Camelimonas abortus UK34/07-5(T) (95.9%) and Chelatococcus daeguensis K106(T) (95.3%). The major cellular fatty acids of strain XZ2(T) were C19 : 0 cyclo ω8c (63.1%), C16 : 0 (15.0%) and C18 : 1ω7c/C18 : 1ω6c (summed feature 8; 8.9%). C18 : 0 3-OH was also detected as the major hydroxylated fatty acid. The respiratory quinone was ubiquinone Q-10. The polar lipid profile included the major compounds phosphatidylcholine and diphosphatidylglycerol, and moderate amounts of phosphatidylethanolamine, phosphatidylglycerol and two unidentified aminolipids. The predominant compound in the polyamine pattern was spermidine. These chemotaxonomic data supported the affiliation of strain XZ2(T) to the genus Camelimonas. The DNA-DNA hybridization value between strain XZ2(T) and Camelimonas lactis M 2040(T) was 43.5 ± 0.6%. DNA-DNA hybridization data as well as biochemical and physiological characteristics strongly supported the genotypic and phenotypic differentiations between strain XZ2(T) and Camelimonas lactis M 2040(T). Therefore, strain XZ2(T) represents a novel species of the genus Camelimonas, for which the name Camelimonas fluminis sp. nov. is proposed. The type strain is XZ2(T) ( = KCTC 42282(T) = ACCC 19738(T)).

Devosia honganensis sp. nov., isolated from the soil of a chemical factory.

A Gram-negative, strictly aerobic, yellow-pigmented and rod-shaped bacterium, designated strain NSL10(T), was isolated from the waste surface soil of a chemical factory in Hongan, China. Strain NSL10(T) was found to grow optimally at pH 7.0, 30 °C and in the absence of NaCl in modified LB medium. Cells were found to be positive for catalase and oxidase. The G+C content of the total DNA was determined to be 66.8 mol%. The 16S rRNA gene sequence of strain NSL10(T) showed the highest similarity to that of Devosia albogilva IPL15(T) (96.80 %), followed by Devosia geojensis BD-c194(T) (96.46 %) and Devosia chinhatensis IPL18(T) (96.27 %). The major cellular fatty acids of strain NSL10(T) were identified as C18:1 ω7c/C18:1 ω6c (48.2 %) and C16:0 (17.7 %). The major polar lipids were identified as diphosphatidylglycerol, phosphatidylglycerol, two unidentified glycolipids and an unidentified compound. Minor amounts of unidentified glycolipids and unidentified polar lipids were also detected. These chemotaxonomic data supported the affiliation of strain NSL10(T) to the genus Devosia. In conclusion, on the basis of biochemical, physiological characteristics and molecular properties, strain NSL10(T) represents a novel species within the genus Devosia, for which the name Devosia honganensis sp. nov., is proposed. The type strain is NSL10(T) (=KCTC 42281(T) = ACCC 19737(T)).

Selective ion transport in large-area graphene oxide membrane filters driven by the ionic radius and electrostatic interactions.

Filters made of graphene oxide (GO) are promising for purification of water and selective sieving of specific ions; while some results indicate the ionic radius as the discriminating factor in the sieving efficiency, the exact mechanism of sieving is still under debate. Furthermore, most of the reported GO filters are planar coatings with a simple geometry and an area much smaller than commercial water filters. Here, we show selective transport of different ions across GO coatings deposited on standard hollow fiber filters with an area >10 times larger than typical filters reported. Thanks to the fabrication procedure, we obtained a uniform coating on such complex geometry with no cracks or holes. Monovalent ions like Na+ and K+ can be transported through these filters by applying a low electric voltage, while divalent ions are blocked. By combining transport and adsorption measurements with molecular dynamics simulations and spectroscopic characterization, we unravel the ion sieving mechanism and demonstrate that it is mainly due to the interactions of the ions with the carboxylate groups present on the GO surface at neutral pH.

Three novel xanthones from Garcinia paucinervis and their anti-TMV activity.

Phytochemical investigations of the leaves of Garcinia paucinervis resulted in the isolation of three new xanthones 1-3 and five known analogues 4-8. Structural elucidations of 1-3 were performed by spectral methods such as 1D and 2D (HMQC, HMBC, and ROESY) NMR spectroscopy, in addition to high resolution mass spectrometry. Compounds 1-3 showed anti-TMV activities, with inhibition rates above 20%, especially for 1, which had a lower IC50 value of 21.4 µM.

Quantitative detection of the Ralstonia solanacearum species complex in soil by qPCR combined with a recombinant internal control strain.

IMPORTANCE: DNA-based detection and quantification of soil-borne pathogens, such as the Ralstonia solanacearum species complex (RSSC), plays a vital role in risk assessment, but meanwhile, precise quantification is difficult due to the poor purity and yield of the soil DNA retrieved. The internal sample process control (ISPC) strain RsPC we developed solved this problem and significantly improved the accuracy of quantification of RSSC in different soils. ISPC-based quantitative PCR detection is a method especially suitable for the quantitative detection of microbes in complex matrices (such as soil and sludge) containing various PCR inhibitors and for those not easy to lyse (like Gram-positive bacteria, fungi, and thick-wall cells like resting spores). In addition, the use of ISPC strains removes additional workload on the preparation of high-quality template DNA and facilitates the development of high-throughput quantitative detection techniques for soil microbes.

NtSWEET1 promotes tobacco resistance to Fusarium oxysporum-induced root rot disease.

Sugars Will Eventually be Exported Transporter (SWEET) is a newly characterized family of sugar transporters, which plays critical roles in plant-pathogen interactions. However, the function of SWEET in tobacco and its interaction with Fusarium oxysporum, a causal agent of root rot, remain unclear. This study aimed to dissect the function of NtSWEETs in tobacco root rot using stem bases from tobacco plants inoculated with F. oxysporum. RNA-sequencing (RNA-Seq) analysis was performed, and the results indicated that Sucrose Transporter 4 (NtSUC4), Sugar Transporter 12 (NtSTP12), Hexose Transporter 6 (NtHEX6), NtSWEET1, NtSWEET3b, and NtSWEET12 were downregulated by infection with F. oxysporum. The expression of NtSWEET1, but not of NtSUC4, NtSTP12, NtHEX6, NtSWEET3b, or NtSWEET12, was suppressed at all the time points tested after inoculation with F. oxysporum. The NtSWEET1-green fluorescent protein was localized on the plasma membrane and possessed the ability to transport glucose, fructose and galactose. Compared with the wild-type plants, NtSWEET1 RNAi plants were more susceptible to root rot, indicating that NtSWEET1 positively regulated the defense of tobacco against root rot. This study identified the role of SWEETs in tobacco and their interaction with F. oxysporum. The results might be useful in protecting tobacco plants from root rot.

A robust, modular approach to produce graphene-MOx multilayer foams as electrodes for Li-ion batteries.

Major breakthroughs in batteries would require the development of new composite electrode materials, with a precisely controlled nanoscale architecture. However, composites used for energy storage are typically a disordered bulk mixture of different materials, or simple coatings of one material onto another. We demonstrate here a new technique to create complex hierarchical electrodes made of multilayers of vertically aligned nanowalls of hematite (Fe2O3) alternated with horizontal spacers of reduced graphene oxide (RGO), all deposited on a 3D, conductive graphene foam. The RGO nanosheets act as porous spacers, current collectors and protection against delamination of the hematite. The multilayer composite, formed by up to 7 different layers, can be used with no further processing as an anode in Li-ion batteries, with a specific capacity of up to 1175 µA h cm-2 and a capacity retention of 84% after 1000 cycles. Our coating strategy gives improved cyclability and rate capacity compared to conventional bulk materials. Our production method is ideally suited to assemble an arbitrary number of organic-inorganic materials in an arbitrary number of layers.

SNARE proteins SYP22 and VAMP727 negatively regulate plant defense.

Soluble N-ethylmaleimide sensitive factor attachment protein receptors (SNAREs) are the key regulators control trafficking of cargo proteins to their final destinations and plays key role in plant development; however, their roles in plant defense remain largely unknown. R-SNARE VAMP727 and Qa-SNARE SYP22 were previously reported to associate with vacuolar protein deposition and brassinosteroids (BRs) receptor BRI1 plasma membrane targeting. Here, we identified that VAMP727 and SYP22 are induced by infection of root-knot nematode (RKN), a plant pathogen, which cause severe growth defect and yield loss. Furthermore, decreased root-knot nematode (RKN) invasion, growth and disease index were observed in bri1-5 and SYP22ND, a SYP22 negative dominant mutants when compared to control plants. Overall, our results suggest that VAMP727-SYP22 SNARE complexes regulate plant defense might be via control of abundances of BRI1 on the plasma membrane.

Ralstonia chuxiongensis sp. nov., Ralstonia mojiangensis sp. nov., and Ralstonia soli sp. nov., isolated from tobacco fields, are three novel species in the family Burkholderiaceae.

Eight Gram-negative, aerobic, motile with paired polar flagella and rod-shaped bacteria were isolated from six tobacco fields in Yunnan, PR China. 16S rRNA gene sequence analysis revealed that all the strains belonged to the genus Ralstonia. Among them, strain 22TCCZM03-6 had an identical 16S rRNA sequence to that of R. wenshanensis 56D2T, and the other strains were closely related to R. pickettii DSM 6297T (98.34­99.86%), R. wenshanensis 56D2T (98.70­99.64%), and R. insidiosa CCUG 46789T (97.34­98.56%). Genome sequencing yielded sizes ranging from 5.17 to 5.72 Mb, with overall G + C contents of 63.3­64.1%. Pairwise genome comparisons showed that strain 22TCCZM03-6 shared average nucleotide identity (ANI) and digital DNA­DNA hybridization (dDDH) values above the species cut-off with R. wenshanensis 56D2T, suggesting that strain 22TCCZM03-6 is a special strain of the R. wenshanensis. Five strains, including 21MJYT02-10T, 21LDWP02-16, 22TCJT01-1, 22TCCZM01-4, and 22TCJT01-2, had ANI values >95% and dDDH values >70% when compared with each other. These five strains had ANI values of 73.32­94.17% and dDDH of 22.0­55.20% with the type strains of the genus Ralstonia individually, supporting these five strains as a novel species in the genus Ralstonia. In addition, strains 21YRMH01-3T and 21MJYT02-11T represent two independent species. They both had ANI and dDDH values below the thresholds for species delineation when compared with the type species of the genus Ralstonia. In strains 21YRMH01-3T and 21MJYT02-10T, the main fatty acids were summed features 3, 8, and C16:0; however, strain 21MJYT02-11T contained C16:0, cyclo-C17:0, and summed features 3 as major fatty acids. The main polar lipids, including diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine, were identified from strains 21YRMH01-3T, 21MJYT02-10T, and 21MJYT02-11T. The ubiquinones Q-7 and Q-8 were also detected in these strains, with Q-8 being the predominant quinone. Based on the above data, we propose that the eight strains represent one known species and three novel species in the genus Ralstonia, for which the names Ralstonia chuxiongensis sp. nov., Ralstonia mojiangensis sp. nov., and Ralstonia soli sp. nov. are proposed. The type strains are 21YRMH01-3T (=GDMCC 1.3534T = JCM 35818T), 21MJYT02-10T (=GDMCC 1.3531T = JCM 35816T), and 21MJYT02-11T (=GDMCC 1.3532T = JCM 35817T), respectively.

Synergic Exfoliation of Graphene with Organic Molecules and Inorganic Ions for the Electrochemical Production of Flexible Electrodes.

A facile and efficient method based on electrochemistry for the production of graphene-based materials for electronics is demonstrated. Uncharged acetonitrile molecules are intercalated in graphite by electrochemical treatment, owing to the synergic action of perchlorate ions dissolved in acetonitrile. Then, acetonitrile molecules are decomposed with microwave irradiation, which causes gas production and rapid graphite exfoliation, with an increase in the graphite volume of up to 600 %. Upon further processing and purification, highly dispersible nanosheets are obtained that can be processed into thin layers by roll-to-roll transfer or into thicker electrodes with excellent capacitance stability upon extensive charging/discharging cycles. The good exfoliation yield (>50 % of monolayers), minimal oxidation damage and good electrochemical stability of the nanosheets obtained were confirmed by scanning force and electron microscopy, as well as Raman spectroscopy and galvanostatic analyses.

A new sesquiterpene from endophytic fungus Aspergillus sp.

A fungal strain named YLF-14 was isolated from the leaf of Altingia yunnunensis. Based on the sequence at the internal transcribed spacer (ITS) region, the strain was identified as an Aspergillus sp.. A new sesquiterpene 5ß,8aß-dimethyl-3,4,4aß,5,6,7,8,8a-octahydronaphthalene-1,2,5α-trimethanol (1) and a known compound 12-N-methylcyclo-(L-tryptophyl-L-phenylalanyl) (2) were isolated from the culture of this strain. Bioassay experiments showed that the two compounds had no obvious effect on the growth of tested bacteria and nematodes.

Detection of two fungal biocontrol agents against root-knot nematodes by RAPD markers.

The strain ZK7 of Pochonia chlamydosporia var. chlamydosporia and IPC of Paecilomyces lilacinus are highly effective in the biological control against root-knot nematodes infecting tobacco. When applied, they require a specific monitoring method to evaluate the colonization and dispersal in soil. In this work, the randomly amplified polymorphic DNA (RAPD) technique was used to differentiate between the two individual strains and 95 other isolates, including isolates of the same species and common soil fungi. This approach allowed the selection of specific fragments of 1.2 kb (Vc1200) and 2.0 kb (Vc2000) specific for ZK7, 1.4 kb (P1400) and 0.85 kb (P850) specific for IPC, using the random Primers OPL-02, OPD-05, OPD-05 and OPC-11, respectively. These fragments were cloned, sequenced, and used to design sequence-characterized amplification region (SCAR) primers specific for the two strains. In classical polymerase chain reaction (PCR), with serial dilution of ZK7 and IPC pure culture DNAs template, the detection limits of these oligonucleotide SCAR-PCR primers were found to be 10, 1000, 500, 100 pg, respectively. In the dot blotting, digoxigenin (DIG)-labeled amplicons from these four primers specifically recognized the corresponding fragments in the DNAs template of these two strains. The detection limit of these amplicons were 0.2, 0.2, 0.5, 0.5 mug, respectively.