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The complete genome sequence of a new virus, provisionally named "balloon flower endornavirus" (BfEV), was determined following virus isolation from leaves of a balloon flower (Platycodon grandiflorum) exhibiting severe leaf shrinkage disease in Anhui Province, China. The 15,180-nucleotide genome sequence of BfEV shares 40.52% amino acid (aa) sequence identity and 98% coverage with the polyprotein of Helianthus annuus endornavirus (HaEV). The open reading frame (ORF) encodes a deduced 4,887-aa polyprotein with RNA-dependent RNA polymerase (RdRp), viral helicase (Hel) and glycosyltransferase (GT) domains. Phylogenetic analysis of the amino acid sequences of RdRp places BfEV alongside members of the genus Alphaendornavirus in the family Endornaviridae. To our knowledge, this is the first report of a complete genome sequence of a novel alphaendornavirus identified in balloon flower.

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The complete genome sequence of a new virus, provisionally named tobacco virus 2 (TV2), was determined and identified from leaves of tobacco (Nicotiana tabacum) exhibiting leaf mosaic, yellowing, and deformity, in Anhui Province, China. The genome sequence of TV2 comprises 5,979 nucleotides, with 87% nucleotide sequence identity to potato leafroll virus (PLRV). Its genome organization is similar to that of PLRV, containing six open reading frames (ORFs) that potentially encode proteins with putative functions in cell-to-cell movement and suppression of RNA silencing. Phylogenetic analysis of the nucleotide sequence placed TV2 alongside members of the genus Polerovirus in the family Luteoviridae. To the best our knowledge, this study is the first report of a complete genome sequence of a new polerovirus identified in tobacco.

The complete genome sequence of a novel virus, provisionally named tobacco virus 1 (TV1), was determined, and this virus was identified in leaves of tobacco (Nicotiana tabacum) exhibiting leaf mosaic and yellowing symptoms in Anhui Province, China. The genome sequence of TV1 consists of 15,395 nucleotides with 61.6 % nucleotide sequence identity to mint virus 1 (MV1). Its genome organization is similar to that of MV1, containing nine open reading frames (ORFs) that potentially encode proteins with putative functions in virion assembly, cell-to-cell movement and suppression of RNA silencing. Phylogenetic analysis of the heat shock protein 70 homolog (HSP70h) placed TV1 alongside members of the genus Closterovirus in the family Closteroviridae. To our knowledge, this study is the first report of the complete genome sequence of a closterovirus identified in tobacco.

Fusaric acid (FA), a non-specific toxin produced mainly by Fusarium spp., can cause programmed cell death (PCD) in tobacco suspension cells. The mechanism underlying the FA-induced PCD was not well understood. In this study, we analyzed the roles of hydrogen peroxide (H2O2) and mitochondrial function in the FA-induced PCD. Tobacco suspension cells were treated with 100 μM FA and then analyzed for H2O2 accumulation and mitochondrial functions. Here we demonstrate that cells undergoing FA-induced PCD exhibited H2O2 production, lipid peroxidation, and a decrease of the catalase and ascorbate peroxidase activities. Pre-treatment of tobacco suspension cells with antioxidant ascorbic acid and NADPH oxidase inhibitor diphenyl iodonium significantly reduced the rate of FA-induced cell death as well as the caspase-3-like protease activity. Moreover, FA treatment of tobacco cells decreased the mitochondrial membrane potential and ATP content. Oligomycin and cyclosporine A, inhibitors of the mitochondrial ATP synthase and the mitochondrial permeability transition pore, respectively, could also reduce the rate of FA-induced cell death significantly. Taken together, the results presented in this paper demonstrate that H2O2 accumulation and mitochondrial dysfunction are the crucial events during the FA-induced PCD in tobacco suspension cells.

Fusaric acid (FA) is a nonhost-selective toxin mainly produced by Fusarium oxysporum, the causal agent of plant wilt diseases. We demonstrate that FA can induce programmed cell death (PCD) in tobacco suspension cells and the FA-induced PCD is modulated by nitric oxide (NO) signalling. Cells undergoing cell death induced by FA treatment exhibited typical characteristics of PCD including cytoplasmic shrinkage, chromatin condensation, DNA fragmentation, membrane plasmolysis, and formation of small cytoplasmic vacuoles. In addition, caspase-3-like activity was activated upon the FA treatment. The process of FA-induced PCD was accompanied by a rapid accumulation of NO in a FA dose-dependent manner. Pre-treatment of cells with NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) or NO synthase inhibitor N G-monomethyl-arginine monoacetate (L-NMMA) significantly reduced the rate of FA-induced cell death. Furthermore, the caspase-3-like activity and the expression of PAL and Hsr203J genes were alleviated by application of cPTIO or L-NMMA to FA-treated tobacco cells. This indicates that NO is an important factor involved in the FA-induced PCD. Our results also show that pre-treatment of tobacco cells with a caspase-3-specific inhibitor, Ac-DEVD-CHO, can reduce the rate of FA-induced cell death. These results demonstrate that the FA-induced cell death is a PCD and is modulated by NO signalling through caspase-3-like activation.

21 and 24Â nt peak distribution of the libraries. Figure S2 (a,b,c). Length distribution of total sRNAs (18 to 30Â nt) in the nine libraries. Figure S3. Distribution of siRNA Reads on Reference Genome shows coverage across the reference. Figure S4. Phylogenetic analyses of isolates of the genus Potyvirus and some selected group members based on complete genome sequences, generated using the neighbor-joining method and MEGA6 software. The percentage of replicate trees in which the associated taxa clustered together in the bootstrap test (1000 replicates) is shown next to the branches. Figure S5. Phylogenetic analyses of CMV Isolates and selected cucumoviruses based on complete genome sequences, generated using the neighbor-joining method and MEGA6 software. The percentage of replicate trees in which the associated taxa clustered together in the bootstrap test (1000 replicates) is shown next to the branches. Figure S6. Phylogenetic analyses of isolates of the genus Poleroviruss (A) and Tobamovirus (B) based on complete genome sequences, generated using the neighbor-joining method and MEGA6 software. The percentage of replicate trees in which the associated taxa clustered together in the bootstrap test (1000 replicates) is shown next to the branches. Figure S7a and b. Putative recombination event involving (a) Potato virus Y and (b) Cucumber mosaic virus isolates from Tobacco calculated by Recombination Detection Program v. 4.16. (PPTX 466Â kb)

Primer sets used in this study for RT-PCR to bridge the gaps between the assembled contigs of each isolates. Table S2. Strain, accession numbers and origin of reported Cucumber mosaic virus isolates used for phylogenetic comparison of sequence in this study. Table S3. Strain, accession numbers and origin of reported Potato virus Y isolates used for phylogenetic comparison of sequence in this study. Table S4. Strain, accession numbers and origin of reported TMV isolates retrieved from Genbank used for phylogenetic comparison and recombination analysis of sequence in this study. (DOCX 25Â kb)

Primer sets used in this study for RT-PCR to bridge the gaps between the assembled contigs of each isolates. Table S2. Strain, accession numbers and origin of reported Cucumber mosaic virus isolates used for phylogenetic comparison of sequence in this study. Table S3. Strain, accession numbers and origin of reported Potato virus Y isolates used for phylogenetic comparison of sequence in this study. Table S4. Strain, accession numbers and origin of reported TMV isolates retrieved from Genbank used for phylogenetic comparison and recombination analysis of sequence in this study. (DOCX 25Â kb)

Phospholipase C (PLC) plays important roles in regulating various biological processes in eukaryotes. Currently, little is known about the function of PLC in filamentous fungi, especially the plant pathogenic fungi. Fusarium graminearum is the causal agent of Fusarium head blight in many cereal crops. BLAST search revealed that Fusarium genome contains six FgPLC genes. Using quantitative RT-PCR, different FgPLC gene expressions in mycelia were analyzed. To investigate the role of FgPLC in F. graminearum biology, a pharmacological study using a known inhibitor of PLC (U73122) was conducted. Results showed that inhibition of FgPLC resulted in significant alterations of mycelial growth, conidiation, conidial germination, perithecium formation, and expressions of Tri5 and Tri6 genes. As expected, the treatment of F. graminearum with U73343, an inactive analog of U73122, showed no effect on F. graminearum biology. Our results suggested strongly that FgPLC plays important roles in F. graminearum growth and development.

A collection of 41 Ralstonia solanacearum (RS) strains isolated from bacterial wilted tobacco collected in 10 Chinese provinces was investigated based on their biovar, heterogeneity within an axenic laboratory culture, and growth to determine the current distribution pattern of tobacco RSstrains in China as well as to provide theoretic guidance to disease control. Of the 41 isolates, 18 belonged to typical biovars (bv1:1, bv2:4, bv3:10, and bv5:3) and 23 to atypical biovars. This classification was based on their ability to oxidize three hexose (lactose, maltose, and cellobiose) and three disaccharides (manitol, sobitol, and dulcite). Of the 23 strains in atypical biovars, a group closed to bv3 (utilized all the other five carbon sources except dulcite) accounted for 73.9%. Heterogeneity within an axenic culture determined through flow cytometry was initially used for RS. The results showed that the descending order rates of heterogeneity index were 19.5, 24.4, 31.7, and 24.4%, respectively. Growth of different strains in static culture showed tha267–276,t the rates of absorbance value from strong to weak were 58.3, 31.7, and 10%, respectively. All the results above showed that the physiological characteristics of RS strains isolated from different geographical regions were diverse. Key words: Ralstonia solanacearum, polymorphism, biovar, heterogeneity, growth.

This paper describes the results of experiments to test the effect of the larvae of Tenebrio molitor Linnaeus on the immune systems of mice. Mice were given a decoction of T. molitor in water at doses of 1.87, 3.75 and 7.50 g/kg/d for four weeks, after which their immune function was studied. The results indicate that T. molitor observably enhanced the carbon expurgatory index and phagocytic index. The half of hemolysis values in serum of treated mice increased compared to the control group. Furthermore, serum nitric oxide (NO) content in all treatment groups was higher than that of the control group whereas acid phosphatase and alkaline phosphatase activity was only significantly higher in the high dose group relative to the control group. We conclude that T. molitor can enhance the immune function of mice and therefore, this insect has the potential of a health food supplement. Keywords: Tenebrio molitor Linnaeus, mice, immunoregulation, immunological function

Background The invasion of plant by viruses cause major damage to plants and reduces crop yield and integrity. Devastating plant virus infection has been experienced at different times all over the world, which are attributed to different events of mutation, re-assortment and recombination occurring in the viruses. Strategies for proper virus management has been mostly limited to eradicating the vectors that spreads the plant viruses. However, development of prompt and effective diagnostic methods are required to monitor emerging and re-emerging diseases that may be symptomatic or asymptomatic in the plant as well as the genetic variation and evolution in the plant viruses. A survey of plant viruses infecting field-grown Tobacco crop was conducted in Anhui Province of China by the deep sequencing of sRNAs. Methods Survey of plant viruses infecting Tobacco was carried based on 104 samples collected across the province. Nine different sRNA libraries was prepared and custom-made bioinformatics pipeline coupled with molecular techniques was developed to sequence, assemble and analyze the siRNAs for plant virus discovery. We also carried out phylogenetic and recombination analysis of the identified viruses. Results Twenty two isolates from eight different virus species including Cucumber mosaic virus, Potato virus Y, Tobacco mosaic virus, Tobacco vein banding Mosaic virus, Pepper mottle virus, Brassica yellow virus, Chilli venial mottle virus, Broad bean wilt virus 2 were identified in tobacco across the survey area. The near-complete genome sequence of the 22 new isolates were determined and analyzed. The isolates were grouped together with known strains in the phylogenetic tree. Molecular variation in the isolates indicated the conserved coding regions have majorly a nucleotide sequence identity of 80-94 % with previously identified isolates. Various events of recombination were discovered among some of the isolates indicating that two or more viruses or different isolates of one virus infect the same host cell. Conclusion This study describes the discovery of a consortium of plant viruses infecting Tobacco that are broadly distributed in Anhui province of China. It also demonstrates the effectiveness of NGS in identifying plant viruses without a prior knowledge of the virus and the genetic diversity that enhanced mixed infection. Electronic supplementary material The online version of this article (doi:10.1186/s12985-016-0639-7) contains supplementary material, which is available to authorized users.