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Tobacco Mosaic Virus (tobacco + mosaic_virus)
Selected AbstractsA new catalytic activity from tobacco converting 2-coumaric acid to salicylic aldehydePHYSIOLOGIA PLANTARUM, Issue 3 2007Jacek Malinowski Salicylic acid (SA) mediates plant response to pathogen invasion, resulting in hypersensitive response and in the formation of systemic acquired resistance. It is well known that Nicotiana tabacum and other plants respond to Tobacco Mosaic Virus (TMV) infection by increasing the content of SA but the details of SA biosynthesis are still not fully understood. Generally, SA may originate directly from isochorismate (Arabidopsis thaliana), or its C6,C1 skeleton could be synthesized via the phenylpropanoid pathway by ,-oxidation of trans -cinnamic acid (N. tabacum), 2-coumaric acid (OCA) (Gaulteria procumbens, Lycopersicum esculentum) or by retro-aldol reaction of trans -cinnamoyl-CoA (Hypericum androsaemum). We report here a novel putative enzyme activity from tobacco, salicylic aldehyde synthase (SAS), catalysing non-oxidative formation of salicylic aldehyde (SALD) directly from OCA. This chain-shortening activity is similar to that of 4-hydroxybenzaldehyde synthase from Vanilla planifolia, Lithospermum erythrorhizon, Daucus carota, Solanum tuberosum and Polyporus hispidus but the enzyme differs in the kinetics of the reaction, substrate specificity and requirements for reducing cofactors. SAS activity is constitutively expressed in healthy tobacco leaves and doubles as a result of infection with TMV. Moreover, the product of SAS activity,SALD, applied exogenously on tobacco leaves, stimulates peroxidase activity and enhances resistance to consecutive infection with TMV. These observations could suggest a contribution of SAS and SALD to the response of tobacco to TMV infection. [source] Surface Modification of Tobacco Mosaic Virus with "Click" ChemistryCHEMBIOCHEM, Issue 4 2008Michael A. Bruckman Click conjugation of tobacco mosaic virus: As a prototype of "click" chemistry, the CuI catalyzed azide-alkyne cycloaddition reaction in combination with diazonium-coupling proved to be an efficient, versatile, and benign method to conjugate a wide range of compounds to phenolic groups of protein tyrosines. In particular, plant virus tobacco mosaic virus was chosen as a multivalent protein scaffold to demonstrate this bioconjugation strategy. [source] Discovery of Bitriazolyl Compounds as Novel Antiviral Candidates for Combating the Tobacco Mosaic Virus.CHEMINFORM, Issue 33 2006Yi Xia Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Evidence for plant viruses in the region of Argentina Islands, AntarcticaFEMS MICROBIOLOGY ECOLOGY, Issue 2 2007Valery Polischuk Abstract This work focused on the assessment of plant virus occurrence among primitive and higher plants in the Antarctic region. Sampling occurred during two seasons (2004/5 and 2005/6) at the Ukrainian Antarctic Station ,Academician Vernadskiy' positioned on Argentina Islands. Collected plant samples of four moss genera (Polytrichum, Plagiatecium, Sanionia and Barbilophozia) and one higher monocot plant species, Deschampsia antarctica, were further subjected to enzyme-linked immunosorbent assay to test for the presence of common plant viruses. Surprisingly, samples of Barbilophozia and Polytrichum mosses were found to contain antigens of viruses from the genus Tobamovirus, Tobacco mosaic virus and Cucumber green mottle mosaic virus, which normally parasitize angiosperms. By contrast, samples of the monocot Deschampsia antarctica were positive for viruses typically infecting dicots: Cucumber green mottle mosaic virus, Cucumber mosaic virus and Tomato spotted wilt virus. Serological data for Deschampsia antarctica were supported in part by transmission electron microscopy observations and bioassay results. The results demonstrate comparatively high diversity of plant viruses detected in Antarctica; the results also raise questions of virus specificity and host susceptibility, as the detected viruses normally infect dicotyledonous plants. However, the means of plant virus emergence in the region remain elusive and are discussed. [source] Ubiquitination of TMV Coat Protein Aggregates in Infected Tobacco LeavesJOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2003J. Hamacher Abstract Protein extracts from Tobacco mosaic virus (TMV) infected young tobacco leaves exhibiting strong symptoms contain higher amounts of ubiquitin conjugates in comparison with non-infected control plants presumably due to stress reactions of host cells. Western blots with antibodies against TMV indicate as well an increase in coat protein or in ubiquitinated coat protein subunits. Immunogold labelling of infected leaf material revealed the accumulation of large amounts of coat protein in opaque inclusions which also reacted strongly with ubiquitin antibodies. These inclusions appear in close vicinity to chloroplasts in chlorotic areas of the leaf. It is concluded that most of the ubiquitin conjugates found in Western blots are due to ubiquitinated coat protein. As a consequence, a considerable amount of coat protein cannot be used for correct capsid construction as the stabilizing lysine residues are blocked by ubiquitination. [source] Proteomic analysis of tobacco mosaic virus-infected tomato (Lycopersicon esculentum M.) fruits and detection of viral coat proteinPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue S1 2006Juan Casado-Vela Abstract Tobacco mosaic virus (TMV) is a widespread plant virus from the genus Tobamovirus that affects tobacco and tomato plants causing a pathology characterised by cell breakage and disorganisation in plant leaves and fruits. In this study we undertook a proteomic approach to investigate the molecular and biochemical mechanisms potentially involved in tomato fruit defence against the viral infection. The comparison of 2-D gels from control and TMV-infected but asymptomatic tomato fruits revealed changes in several proteins. The differential expression of peptidases, endoglucanase, chitinase and proteins participating in the ascorbate-glutathione cycle in infected fruits suggests that pathogenesis-related proteins and antioxidant enzymes may play a role in the protection against TMV infection. TMV coat protein appeared as a prominent spot in 2-D gels from TMV-infected asymptomatic fruits. A Triton X-114 phase-partitioning step of tomato protein extracts favoured the solubilisation of TMV coat protein and the enrichment of two aminopeptidases not present in control fruits. PMF and MS/MS data of the 2-D gel-isolated TMV coat protein is proposed as a powerful analysis method for the simultaneous tobamovirus detection, species determination and strain differentiation in virus-infected fruit commodities. [source] Synthesis of High-Surface-Area Platinum Nanotubes Using a Viral TemplateADVANCED FUNCTIONAL MATERIALS, Issue 8 2010. Górzny, Marcin Abstract A novel method for the synthesis of high-active-surface-area, platinum,tobacco mosaic virus (Pt,TMV) nanotubes is presented. A platinum salt is reduced to its metallic form on the external surface of a rod-shaped TMV by methanol, which serves as a solvent and reductant simultaneously. It was found that for the same Pt loading the Pt,TMV nanotubes had an electrochemically active surface area between 4 to 8 times larger than similarly sized Pt nanoparticles. A Pt,TMV catalyst displays greater stability in acidic conditions than those based on nanoparticles. When used as a catalyst for methanol oxidation, these Pt nanotubes display a 65% increase in catalytic mass activity compared to that based on Pt nanoparticles. [source] Soil-Borne Wheat Mosaic Virus (SBWMV) 37 kDa Protein Rescues Cell-to-Cell and Long-Distance Movement of an Immobile Tobacco Mosaic Virus Mutant in Nicotiana benthamiana, a Non-Host of SBWMVJOURNAL OF PHYTOPATHOLOGY, Issue 1 2005C. Zhang Abstract To verify the role and examine the functional range of the 37 kDa putative movement protein (MP) of soil-borne wheat mosaic virus (SBWMV), the 37 kDa gene was inserted into an infectious tobacco mosaic virus (TMV)-based expression vector (p30B), to generate p30BMP. The 30 kDa cell-to-cell MP gene of TMV was then inactivated (in p30BMP to give p30B,MP) by a frameshift mutation which removed 80 amino acids from its C-terminus. Systemic infection of Nicotiana benthamiana plants occurred following inoculation with in vitro transcripts of p30BMP or p30B,MP. Progeny viral RNAs from inoculated and systemically infected leaves were analysed by reverse transcriptase polymerase chain reaction and ApaI digestion, and by sequencing. The 30 kDa TMV MP or its truncated form were detected, respectively, in Western blots of cell wall protein extracts from p30BMP-transcript or p30B,MP-transcript inoculated or systemically infected N. benthamiana leaves. High levels of SBWMV 37 kDa MP were detected in all cases. The results suggest that the 37 kDa protein of SBWMV, a monocotyledonous-infecting furovirus, can complement both cell-to-cell and long-distance movement functions in a defective heterologous virus (TMV) in N. benthamiana, a non-host of SBWMV. [source] Surfactant-Induced Amorphous Aggregation of Tobacco Mosaic Virus Coat Protein: A Physical Methods ApproachMACROMOLECULAR BIOSCIENCE, Issue 2 2008Yuliy V. Panyukov Abstract The interactions of non-ionic surfactant Triton X-100 and the coat protein of tobacco mosaic virus, which is an established model for both ordered and non-ordered protein aggregation, were studied using turbidimetry, differential scanning calorimetry, isothermal titration calorimetry, and dynamic light scattering. It was found that at the critical aggregation concentration (equal to critical micelle concentration) of 138,×,10,6M, Triton X-100 induces partial denaturation of tobacco mosaic virus coat protein molecules followed by protein amorphous aggregation. Protein aggregation has profound ionic strength dependence and proceeds due to hydrophobic sticking of surfactant-protein complexes (start aggregates) with initial radii of 46 nm. It has been suggested that the anionic surfactant sodium dodecyl sulfate forms mixed micelles with Triton X-100 and therefore reverses protein amorphous aggregation with release of protein molecules from the amorphous aggregates. A stoichiometric ratio of 5 was found for Triton X-100-sodium dodecyl sulfate interactions. [source] Antiphytoviral activity of bruceine-D from Brucea javanica seedsPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 2 2008Jian-Guo Shen Abstract BACKGROUND:Brucea javanica (L.) Merr. is widely distributed throughout the southern parts of China and has been used in traditional medicine to treat a variety of diseases. The objective of the present study was to identify the active antiphytoviral compound in the seeds of B. javanica and evaluate the inhibitory activity of the compound against plant virus. RESULTS: Bioassay-guided fractionation of the most active extract from the seeds led to the isolation of an antiphytoviral compound which was identified as bruceine-D by conventional spectroscopy methods. The compound exhibited significant inhibitory activity against the infection and replication of tobacco mosaic virus (TMV), with IC50 values of 13.98 and 7.13 mg L,1 respectively. The compound also showed a strong inhibitory effect on the infectivity of potato virus Y (PVY) and cucumber mosaic virus (CMV). Furthermore, the compound could effectively inhibit systemic TMV infection in the host tobacco plant under glasshouse conditions. CONCLUSION: The results suggested that bruceine-D from Brucea javanica may have the potential to be used as a natural viricide, or a lead compound for new viricides. Copyright © 2007 Society of Chemical Industry [source] Thermographic visualization of cell death in tobacco and ArabidopsisPLANT CELL & ENVIRONMENT, Issue 1 2001L. Chaerle ABSTRACT Pending cell death was visualized by thermographic imaging in bacterio-opsin transgenic tobacco plants. Cell death in these plants was characterized by a complex lesion phenotype. Isolated cell death lesions were preceded by a colocalized thermal effect, as previously observed at sites infected by tobacco mosaic virus (TMV) (Chaerle et al. 1999Nature Biotechnology 17, 813,816). However, in most cases, a coherent front of higher temperature, trailed by cell death, initiated at the leaf base and expanded over the leaf lamina. In contrast to the homogenous thermal front, cell death was first visible close to the veins, and subsequently appeared as discrete spots on the interveinal tissue, as cell death spread along the veins. Regions with visible cell death had a lower temperature because of water evaporation from damaged cells. In analogy with previous observations on the localized tobacco,TMV interaction (Chaerle et al. 1999), the kinetics of thermographic and continuous gas exchange measurements indicated that stomatal closure preceded tissue collapse. Localized spontaneous cell death could also be presymptomatically visualized in the Arabidopsis lsd2 mutant. [source] Chloroplast-generated reactive oxygen species are involved in hypersensitive response-like cell death mediated by a mitogen-activated protein kinase cascadeTHE PLANT JOURNAL, Issue 6 2007Yidong Liu Summary Plant defense against pathogens often includes rapid programmed cell death known as the hypersensitive response (HR). Recent genetic studies have demonstrated the involvement of a specific mitogen-activated protein kinase (MAPK) cascade consisting of three tobacco MAPKs, SIPK, Ntf4 and WIPK, and their common upstream MAPK kinase (MAPKK or MEK), NtMEK2. Potential upstream MAPKK kinases (MAPKKKs or MEKKs) in this cascade include the orthologs of Arabidopsis MEKK1 and tomato MAPKKK,. Activation of the SIPK/Ntf4/WIPK pathway induces cell death with phenotypes identical to pathogen-induced HR at macroscopic, microscopic and physiological levels, including loss of membrane potential, electrolyte leakage and rapid dehydration. Loss of membrane potential in NtMEK2DD plants is associated with the generation of reactive oxygen species (ROS), which is preceded by disruption of metabolic activities in chloroplasts and mitochondria. We observed rapid shutdown of carbon fixation in chloroplasts after SIPK/Ntf4/WIPK activation, which can lead to the generation of ROS in chloroplasts under illumination. Consistent with a role of chloroplast-generated ROS in MAPK-mediated cell death, plants kept in the dark do not accumulate H2O2 in chloroplasts after MAPK activation, and cell death is significantly delayed. Similar light dependency was observed in HR cell death induced by tobacco mosaic virus, which is known to activate the same MAPK pathway in an N -gene-dependent manner. These results suggest that activation of the SIPK/Ntf4/WIPK cascade by pathogens actively promotes the generation of ROS in chloroplasts, which plays an important role in the signaling for and/or execution of HR cell death in plants. [source] Interaction between two mitogen-activated protein kinases during tobacco defense signalingTHE PLANT JOURNAL, Issue 2 2003Yidong Liu Summary Plant mitogen-activated protein kinases (MAPKs) represented by tobacco wounding-induced protein kinase (WIPK) have unique regulation at the level of transcription in response to stresses. By using transcriptional and translational inhibitors, it has been shown previously that WIPK gene expression and de novo protein synthesis are required for the high-level activity of WIPK in cells treated with elicitins from Phytophthora spp. However, regulation of WIPK expression and the role(s) of WIPK in plant disease resistance are unknown. In this report, we demonstrate that WIPK gene transcription is regulated by phosphorylation and de-phosphorylation events. Interestingly, salicylic acid-induced protein kinase (SIPK) was identified as the kinase involved in regulating WIPK gene expression based on both gain-of-function and loss-of-function analyses. This finding revealed an additional level of interaction between SIPK and WIPK, which share an upstream MAPKK, NtMEK2. Depending on whether WIPK shares its downstream targets with SIPK, it could either function as a positive feed-forward regulator of SIPK or initiate a new pathway. Consistent with the first scenario, co-expression of WIPK with the active mutant of NtMEK2 leads to accelerated hypersensitive response (HR)-like cell death in which SIPK also plays a role. Mutagenesis analysis revealed that the conserved common docking domain in WIPK is required for its function. Together with prior reports that (i) WIPK is activated in NN tobacco infected with tobacco mosaic virus, and (ii) PVX virus-induced gene silencing of WIPK attenuated N gene-mediated resistance, we concluded that WIPK plays a positive role in plant disease resistance, possibly through accelerating the pathogen-induced HR cell death. [source] Spatio-temporal expression of patatin-like lipid acyl hydrolases and accumulation of jasmonates in elicitor-treated tobacco leaves are not affected by endogenous levels of salicylic acidTHE PLANT JOURNAL, Issue 5 2002Sandrine Dhondt Summary We have previously isolated three tobacco genes (NtPat) encoding patatin-like proteins, getting rapidly induced during the hypersensitive response (HR) to tobacco mosaic virus, in advance to jasmonate accumulation. NtPAT enzymes are lipid acyl hydrolases that display high phospholipase A2 (PLA2) activity and may mobilize fatty acid precursors of oxylipins. Here, we performed a detailed study of NtPat gene regulation under various biotic and abiotic stresses. PLA2 activity was poorly induced in response to drought, wounding, reactive oxygen intermediates, salicylic acid (SA) or methyl-jasmonate (MJ) whereas the ethylene (ET) precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), provoked a moderate induction. In contrast, PLA2 activity was strongly induced when ACC was combined with MJ, and in response to the bacterium Erwinia carotovora or to the fungus Botrytis cinerea, as well as to treatment with ,-megaspermin, a cell death-inducing protein elicitor. A simplified system based on the infiltration of ,-megaspermin into leaves was used to dissect the spatio-temporal activation of PLA2 activity with regards to the accumulation of jasmonates and to the influence of endogenous SA. NtPat -encoded PLA2 activity was rapidly induced in the infiltrated zone before the appearance of cell death and with some delay in the surrounding living cells. A massive accumulation of 12-oxo-phytodienoic and jasmonic acids occurred in the elicitor-infiltrated zone, but only low levels were detectable outside this area. A similar picture was found in SA-deficient plants, showing that in tobacco, accumulation of jasmonates is not affected by the concomitant HR-induced build-up of endogenous SA. Finally, ET-insensitive plants showed a weakened induction of PLA2 activity outside the elicitor-infiltrated tissue. [source] SVISS , a novel transient gene silencing system for gene function discovery and validation in tobacco plantsTHE PLANT JOURNAL, Issue 5 2002Véronique Gosselé Summary We developed a novel, two-component transient gene silencing system in which the satellite tobacco mosaic virus (STMV) is used as vector for the delivery of inhibitory RNA into tobacco plants and the tobacco mosaic virus strain U2 (TMV-U2) is used as helper virus for supplying replication and movement proteins in trans. The main advantage of the system is that by uncoupling virus replication components from silencing induction components, the intensity of silencing becomes more pronounced. We call this system satellite virus-induced silencing system (SVISS) and will demonstrate here its robustness, speed and effectiveness. We were able to obtain pronounced and severe knockout phenotypes for a range of targeted endogenous genes belonging to various biochemical pathways and expressed in different plant tissues, such as genes involved in leaf and flower pigmentation, genes for cell wall synthesis in leaf, stem and root tissues or a ubiquitous RNA polymerase gene. By tandem insertion of more than one target gene sequence into the vector, we were able to induce simultaneous knockouts of an endogenous gene and a transgene. SVISS is the first transient gene silencing system for Nicotiana tabacum, which is a genetically well-characterized bridging species for the Solanaceae plant family. [source] Activation of a diverse set of genes during the tobacco resistance response to TMV is independent of salicylic acid; induction of a subset is also ethylene independentTHE PLANT JOURNAL, Issue 5 2000Ailan Guo Summary Through differential screening of a cDNA library, we cloned six groups of genes that are expressed relatively early in the inoculated leaves of tobacco resisting infection by tobacco mosaic virus (TMV). Induction of all these genes was subsequently detected in the uninoculated leaves; thus, their expression is associated with the development of both local and systemic acquired resistance. Exogenously applied salicylic acid (SA) was observed to induce these genes transiently. However, analyses with transgenic NahG plants, which are unable to accumulate SA, demonstrated that expression of these genes in TMV-inoculated leaves is mediated via an SA-independent pathway. Because the expression kinetics of these genes differ from those associated with the well-characterized pathogenesis-related protein (PR-1) and phenylalanine ammonia-lyase (PAL) genes, we propose that they belong to a group which we designate SIS, for SA-independent, systemically induced genes. Interestingly, the expression of several SIS genes in the uninoculated leaves of TMV-infected NahG plants was delayed and/or reduced, raising the possibility that SA is involved in activating some of these genes in systemic tissue. Most of the SIS genes were induced by exogenous ethylene. However, analyses of infected NahG plants treated with ethylene action and/or synthesis inhibitors indicated that the TMV-induced expression of several SIS genes is independent of ethylene as well as SA. [source] Purification and expression of a protein elicitor from Alternaria tenuissima and elicitor-mediated defence responses in tobaccoANNALS OF APPLIED BIOLOGY, Issue 3 2010J. Mao A new protein elicitor, PeaT1, was purified from the mycelium of Alternaria tenuissima by column chromatography. PeaT1 was identified as a heat-stable and acidic protein. It induced systemic acquired resistance to tobacco mosaic virus (TMV) in tobacco plants but did not cause hypersensitive response. The elicitor-encoding gene was cloned by rapid amplification of cDNA ends method. Sequence analysis revealed that the cDNA is 624 bp in length and the open reading frame encodes for a polypeptide of 207 amino acids with a nascent polypeptide-associated complex domain. The peaT1 gene was cloned into the expression vector pET-28a and transformed into Escherichia coli BL21 (DE3). The recombinant elicitor also triggered defence responses in intact tobacco plants. The availability of the pure protein offers the possibility to isolate the corresponding receptor and links it to the downstream signalling pathway. [source] Surface Modification of Tobacco Mosaic Virus with "Click" ChemistryCHEMBIOCHEM, Issue 4 2008Michael A. Bruckman Click conjugation of tobacco mosaic virus: As a prototype of "click" chemistry, the CuI catalyzed azide-alkyne cycloaddition reaction in combination with diazonium-coupling proved to be an efficient, versatile, and benign method to conjugate a wide range of compounds to phenolic groups of protein tyrosines. In particular, plant virus tobacco mosaic virus was chosen as a multivalent protein scaffold to demonstrate this bioconjugation strategy. [source] Porphyrin Light-Harvesting Arrays Constructed in the Recombinant Tobacco Mosaic Virus ScaffoldCHEMISTRY - A EUROPEAN JOURNAL, Issue 31 2007Masayuki Endo Dr. Abstract We have demonstrated the construction of multiple porphyrin arrays in the tobacco mosaic virus (TMV) supramolecular structures by self-assembly of recombinant TMV coat protein (TMVCP) monomers, in which Zn-coordinated porphyrin (ZnP) and free-base porphyrin (FbP) were site-selectively incorporated. The photophysical properties of porphyrin moieties incorporated in the TMV assemblies were also characterized. TMV,porphyrin conjugates employed as building blocks self-assembled into unique disk and rod structures under the proper conditions as similar to native TMV assemblies. The mixture of a ZnP donor and an FbP acceptor was packed in the TMV assembly and showed energy transfer and light-harvesting activity. The detailed photophysical properties of the arrayed porphyrins in the TMV assemblies were examined by time-resolved fluorescence spectroscopy, and the energy transfer rates were determined to be 3.1,6.4×109,s,1. The results indicate that the porphyrins are placed at the expected positions in the TMV assemblies. [source] | ||||||||||||||||