Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “TMV”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed1996

The Construction and Complementary Expression of two TMV Defective Particles in Tobacco.

Two defective mutants of the tobacco mosaic virus (TMV), TMVRP and TMVCP were constructed and assembled in vitro. In TMVRP, the 3'-end and part of the TMV coat protein (CP) gene was deleted; in TMRCP, most of the replicase genes were deleted. These mutant particles were separately or complementally inoculated into the tobacco protoplasts by electroporation. The synthesis of TMV coat protein was deteted by immuno dot-blot technique at 2 h after inoculation only in those complementally infected protoplasts. In addition, using the RT/PCR technique, the minus-strand viral RNA of the TMV 3'-end including CP gene was also only detected in those protoplasts which were complementally infected with both of the mutant particles. The synthesis of the minus-strand RNA started to be detectable at 1h after inoculation and it was confirmed by Southern blot analysis.

Journal Article↗
PubMed2003

Involvement of hydrogen peroxide in repression of catalase in TMV-infected resistant tobacco.

Catalases are ubiquitous, and play a role in plant defense against pathogens. We have reported that catalase mRNA and enzyme activity are repressed in the vicinity of hypersensitive tobacco lesions following TMV infection. We wished to identify the signals involved in this repression. Inoculation with TMV reduced catalase levels 26 to 28 h following infection, coincident with the known timing of endogenous salicylic acid (SA) accumulation. Application of SA caused a transient reduction in Ngcat1 mRNA level and catalase activity 4 to 6 h after treatment. However, repression was also observed in transgenic plants harboring the salicylate hydroxylase gene (NahG) and in TMV susceptible plants, which do not accumulate SA following TMV infection. In the same blots there was no induction of PR-1 or enhanced expression of H2O2-inducible glutathione-S-transferase and found that exposure to H2O2 also repressed Ngcat1 mRNA. Our findings suggest that repression of catalase transcription may be caused by the accumulation of H2O2 rather than of SA.

Catalase↗
PubMed1980

The nature of the RNA products synthesized in vitro with a cell-free extract from TMV-infected tobacco leaves.

A cell-free extract containing TMV-RNA replicase was prepared from TMV-infected tobacco leaves. It could synthesize double-stranded RNAs in the presence of four nucleoside triphosphates (among them, UTP was tritium-labelled), magnesium ion and actinomycin D. It was confirmed by polyacrylamide-agarose gel electrophoresis, RNase treatment, thermal denaturation and self annealing that 3H-ds RNAs, obtained from phenol-SDS extraction and Serva cellulose column chromatography, consisted of replicative form (RF) and replicative intermediate (RI) of TMV-RNA, with molecular weights of 40 X 10(6) and 5.0 X 10(6), respectively. Molecular hybridization competition experiment showed that 60-70% of the nascent RNAs in the 3H-ds RNA were plus strand of tMV-RNA.

Cell-Free System↗
PubMed1983

The 5'-terminal sequence of TMV RNA. Question on the polymorphism found in vulgare strain.

The complete nucleotide sequence of TMV RNA (common strain) reported in [Proc. Natl. Acad. Sci. USA (1982) 79, 5818] its 5'-end to be represented by two variants which differed in length. We have tested that result and sequenced the 5'-terminal regions of two strains of TMV RNA (common strain OM and tomato strain L) using cloned cDNA copies. The results showed that the 5'-terminal region of the TMV genome is not polymorphic and that one of the two variants cited above represents a tomato strain but not the common strain.

Base Sequence↗
PubMed1992

Direct RNA polymerase chain reaction for TMV detection in crude cell extracts.

A part of the 30,000 bp transport protein gene of tobacco mosaic virus (TMV) RNA was amplified via direct RNA PCR and via traditional reverse transcription followed by cDNA PCR. Both amplified cDNA products were restricted with NcoI or HaeIII endonucleases and identical restriction fragments were produced. Two efficient methods of viral RNA concentration from an infected tobacco leaf extract were used: both 3-3.5 M sodium acetate alone and 3 M LiCl with 4 M urea quantitatively precipitated TMV RNA from the extracts. TMV RNA thus obtained could be readily amplified by direct RNA PCR. These results demonstrate that direct RNA PCR can be applied for the detection or/and analysis of high molecular weight RNA and for diagnosis of viral infections.

Base Sequence↗
PubMed1992

Codon context effect in virus translational readthrough. A study in vitro of the determinants of TMV and Mo-MuLV amber suppression.

To assess the role of codon context on the efficiency of eukaryotic suppression of termination codons, we have compared, in a rabbit cell-free translation system, the readthrough efficiency related to two synthetic transcripts differing by the codon context around an amber codon. The codon contexts are derived from tobacco mosaic virus (TMV) and Moloney murine leukemia virus (Mo-MuLV) RNAs. The Mo-MuLV-like codon context does not promote suppression. Substituting TMV-derived triplets in the Mo-MuLV-like codon context shows that the two codons downstream from the TMV UAG signal are important determinants of suppression, as recently demonstrated in vivo.

Amino Acid Sequence↗
PubMed1988

The use of thermally activated tritium atoms for structural-biological investigations: the topography of the TMV protein-accessible surface of the virus.

Thermally activated tritium atoms were used for studying the topography of the TMV protein-accessible surface of the virus. The accessibility profile of amino acid residues in a protein polypeptide chain was determined from data on the intramolecular distribution of a tritium label in the TMV protein. It was shown that tryptic peptides T3, T4, T12, the N-terminal region of peptide T1 and the proximal tryptic peptide T8 (located 20 to 25 A (1 A = 0.1 nm) from the viral axis) are accessible to tritium labelling. The fact of tritiation of the viral RNA was detected as well. This evidence was compared with the high-resolution X-ray analysis data for the TMV. A model is suggested to explain the exposure of the buried sites of the virus to thermally activated tritium atoms. The possibilities and limitations of this method in studying the surface topography of proteins in supramolecular systems as well as for location of protein antigenic regions are discussed.

Amino Acid Sequence↗
PubMed1987

Characterization of Tm-1 gene action on replication of common isolates and a resistance-breaking isolate of TMV.

Tm-1 is a gene which confers resistance to infection, in tomatoes, by tobacco mosaic virus (TMV). To investigate the biochemical mechanism of the resistance, we have established cell suspensions of three lines of tomatoes, i.e., +/+ (susceptible, wild-type, no Tm-1 gene), Tm-1/+ (heterozygous for the Tm-1 gene), and Tm-1/Tm-1 (homozygous for the Tm-1 gene). Protoplasts isolated from these cells were inoculated with RNA of the tomato strain L and Lta1 (a resistance-breaking strain which was recently isolated spontaneously from L) of TMV by means of electrophoration. The syntheses of all viral-coded proteins and TMV-specific RNAs could be detected in L-inoculated +/+ and Lta1-inoculated +/+, Tm-1/+, Tm-1/Tm-1 protoplasts, while their production was markedly reduced in L-inoculated Tm-1/+ protoplasts. L strain could multiply in Tm-1/+ protoplasts to a greater extent with less delay when a large amount of inoculum RNA was used. However, viral production was completely blocked in Tm-1/Tm-1 protoplasts even when a large amount of L-RNA was used for inoculation.

Cells, Cultured↗
PubMed1989

Genetic heterogeneity of the RNA genome population of the plant virus U5-TMV.

The genetic heterogeneity in a population of the U5 strain of tobacco mosaic virus (U5-TMV) was studied. The T1 fingerprint characterizing a cloned population did not vary after a new cloning step in the local lesion host Nicotiana tabacum Xanthi-nc, nor during four series of 20 passages in the systemic host N. tabacum Samsum. No heterogeneity was observed among 10 clones derived from the cloned populations, while 1 of 18 clones derived from a 20-fold passaged population differed from the rest in 1 of 55 oligonucleotides. A higher heterogeneity was found in an uncloned field isolate in which 2 of 10 clones differed in type in 1 and 2 oligonucleotides, respectively. These data agree with those reported for bacterial and animal RNA viruses and are compatible with the quasi-species model for RNA populations. On the other hand, the intrapopulational heterogeneities found for U5-TMV are considerably smaller than those reported for other RNA viruses, our data showing a high genetic stability for U5-TMV.

Cloning, Molecular↗
PubMed1991

The TMV movement protein: role of the C-terminal 73 amino acids in subcellular localization and function.

The role of the C-terminal one-third of the tobacco mosaic virus (TMV) 30-kDa movement protein (MP) on its subcellular localization and on virus spread was investigated. We have constructed eight cDNAs encoding MPs with variable size deletions from the C-terminal end. Expression of the truncated proteins was verified in recombinant yeast using an antiserum directed to a synthetic peptide corresponding to 21 amino acids near the N-terminal end of the MP. In transgenic tobacco plants, MP from which more than 55 amino acids were deleted no longer accumulated in the cell wall fraction of a cellular extract, where the complete MP accumulates. Dye diffusion studies showed that both unmodified and modified MPs that accumulate in the cell wall fraction are able to alter plasmodesmatal size exclusion limits. Biological function of the modified MPs was tested in the transgenic plants with the TMV thermosensitive mutant Ls1 and a TMV genomic RNA transcript lacking a functional MP. There was a correlation between the cell wall localization of the modified MPs and its ability to potentiate virus spread. The results presented here demonstrate the dispensability of the C-terminal 55 amino acids of the MP in its subcellular localization in tobacco plants and its role in virus movement. Moreover, our results show that a stretch of 19 amino acids (195 to 213) is essential for localization of the MP to the cell wall fraction of plant cells.

Capsid↗
PubMed1995

Multiple serine phosphorylation sites on the 30 kDa TMV cell-to-cell movement protein synthesized in tobacco protoplasts.

p30, the protein required for cell-to-cell movement of tobacco mosaic virus (TMV), has a slightly reduced mobility on SDS-polyacrylamide gels when isolated by immunoprecipitation from TMV-infected protoplasts compared with that of p30 translated from viral RNA in vitro. Further investigation established a probable cause for the difference in mobility between the two: protoplasts incorporate [32P]orthophosphate into p30 at multiple sites, predominantly as phosphoserine. Tryptic peptide mapping reveals at least five internal phosphopeptides in p30, besides the C-terminal tryptic phosphopeptide already reported, involving at least two distinct domains of the protein (at residues 61-114 and residues 212-231), which may be substrates for different protein kinases. These structural results are consistent with a three-domain model for the TMV movement protein with two regulatory domains similar to that recently proposed on genetic grounds for dianthovirus movement proteins.

Peptide Mapping↗
PubMed1998

Characterization of a tobacco epoxide hydrolase gene induced during the resistance response to TMV.

A clone encoding a putative soluble epoxide hydrolase (EH-1), an enzyme which converts epoxides to diols, was isolated by differential screening of a cDNA library prepared from tobacco mosaic virus (TMV)-infected tobacco leaves. To confirm that EH-1 encodes an epoxide hydrolase, the recombinant EH-1 protein produced in bacteria was shown to have high epoxide hydrolase activity in vitro. Infection of resistant but not susceptible tobacco cultivars induced the accumulation of EH-1 transcripts in both the inoculated and uninoculated, systemic leaves. EH-1 expression was also induced in the inoculated and systemic tissues of TMV-infected NahG plants, which are unable to accumulate salicylic acid (SA). However, EH-1 expression in the inoculated leaves of NahG plants was delayed, whilst in the systemic leaves the induction was both later and weaker, compared to that observed in wild-type plants. Furthermore, exogenously applied SA or its functional analog 2,6-dichloroisonicotinic acid (INA) caused a rapid and transient accumulation of EH-1 transcripts, whereas an inactive SA analog did not. Thus, the induction of EH-1 gene expression appears to be regulated by both SA-independent and SA-dependent pathways. Since EH-1 was expressed only in TMV-resistant tobacco after infection, and the encoded enzyme is thought to help metabolize toxic compounds, we propose that EH-1 may play a role in protection from oxidative damage associated with defense responses. It may also play a role in generating signals for activation of certain defense responses.

Amino Acid Sequence↗
PubMed1995

Transposon tagging of tobacco mosaic virus resistance gene N: its possible role in the TMV-N-mediated signal transduction pathway.

Plants can recognize and resist invading pathogens by signaling the induction of rapid defense responses. Often these responses are mediated by single dominant resistance genes (R genes). The products of R genes have been postulated to recognize the pathogen and trigger rapid host defense responses. Here we describe isolation of the classical resistance gene N of tobacco that mediates resistance to the well-characterized pathogen tobacco mosaic virus (TMV). The N gene was isolated by transposon tagging using the maize Activator (Ac) transposon. We confirmed isolation of the N gene by complementation of the TMV-sensitive phenotype with a genomic DNA fragment. Sequence analysis of the N gene shows that it encodes a protein with an amino-terminal domain similar to that of the cytoplasmic domains of the Drosophila Toll protein and the interleukin 1 receptor in mammals, a putative nucleotide-binding site and 14 imperfect leucine-rich repeats. The presence of these functional domains in the predicted N gene product is consistent with the hypothesis that the N resistance gene functions in a signal transduction pathway. Similarities of N to Toll and the interleukin 1 receptor suggest a similar signaling mechanism leading to rapid gene induction and TMV resistance.

Amino Acid Sequence↗
PubMed2005

Susceptibility of some Lycopersicon species and varieties to cucumber mosaic virus (CMV) and tobacco mosaic virus (TMV).

Susceptibility of 33 Lycopersicon species and varieties to Tobacco mosaic virus (TMV) and Cucumber mosaic virus (CMV) were studied. Plants were mechanically inoculated with the C/U1 strain of TMV and U/246 strain of CMV. Virus infection was checked by symptomatology, DAS ELISA and back inoculation (biotest). All the studied Lycopersicon species and varieties were susceptible to TMV-C/U1. L. esculentum Mill. convar. infiniens Lehm. var. flammatum Lehm., L. esculentum Mill. convar. fruticosum Lehm. var. speciosum Lehm. and L. esculentum Mill. convar. infiniens Lehm. var. validum Bail. showed extreme resistance to CMV-U/246. The other 30 species and varieties were susceptible to CMV-U/246. New compatible and incompatible host-virus relations have been reported. The extreme resistant Lycopersicon varieties could be used as resistance sources in tomato breeding.

Breeding↗
PubMedDate not supplied

[Hormonal status of tobacco variety Samsun NN exposed to synthetic coenzyme Q10 (ubiquinone 50) and TMV infection].

Hormonal system status has been analyzed in leaf disks of hypersensitive tobacco Nicotiana tabacum L. variety Samsun NN during the development of resistance to tobacco mosaic virus (TMV) induced by synthetic coenzyme Q10 (ubiquinone 50). The absolute and relative content of abscisic acid (ABA), indoleacetic acid (IAA), and cytokinins (CKs) was determined after the exposure of leaves to Q10 solution and the subsequent TMV infection. In plants not treated with Q10, CK content increased about 2.5 times 1 day after TMV infection, while a significant increase in the ABA level and a decrease in the IAA level were observed only after 2 days. In the dynamics, Q10 treatment had a protective antiviral effect, significantly decreased the ABA level, and increased the IAA level in sensitized plants compared to nonsensitized ones.

Abscisic Acid↗
PubMedDate not supplied

[Location of the reconstitution initiation sites of TMV Ni2519 RNA].

The nature of temperature sensitivity (ts) of TMV mutant Ni2529 has been studied in experiments on in vitro reconstitution. At permissive temperature (24 degrees C) RNA of Ni2519 can be reassembled into an infective virus. At nonpermissive temperature (33 degrees C) the reassembly of Ni2519 results in defective (ribonuclease-sensitive) particle formation. The RNase-sensitive site of Ni2519 RNA molecule in the defective virus particle is located at a distance of about 600--800 nucleotides from the 3'-end. The reason for the aberrant Ni 2519 reconstitution at 33 degrees C is that initiation of reassembly at nonpermissive temperature occurs simultaneously at two reconstitution initiation sites of Ni2519 RNA. The first site (RISI) is located within about 800--1000 nucleotides from 3'-terminus and corresponds to the origin of assembly region of TMV common strain. The second site (RISII) is located within about 300--520 nucleotides from 3'-terminus and corresponds to the portion of coat protein gene. The RNA site available for RNase attack is located just between the two RIS. Thus, it has been suggested that the ts-phenotype of Ni2519 results from ts-behaviour of the virion RNA molecule itself, i. e. that this mutant represents novel class of TMV ts-mutants.

Microscopy, Electron↗
PubMed1998

Coordinated expression of defense-related genes by TMV infection or salicylic acid treatment in tobacco.

To understand the coordinated functions of the different classes of defense-related genes expressed in plant disease resistance, the expression patterns of pathogenesis related (PR) protein genes and genes involved in antioxidation and the production of secondary metabolites were examined. The expression patterns of the respective defense-related genes were monitored following TMV infection or salicylic acid treatment. Northern blot analyses showed that PR genes such as PR-1, beta-1,3-glucanase and chitinase were strongly induced in tobacco leaves upon TMV infection or salicylic acid treatment. 3-Hydroxy-3-methylglutaryl CoA reductase (HMGR) and phenylalanine ammonialyase (PAL), involved in isoprenoid and phenylpropanoid biosynthesis, respectively, were mildly induced at the late stage of normal hypersensitive response (HR) or after salicylic acid treatment when compared with the PR-gene expressions. However, in acute HR, they were strongly expressed at the early stage. Interestingly, the expression of the antioxidative genes, anionic peroxidase and ascorbate peroxidase, were inversely expressed following TMV infection and salicylic acid treatment. Differential expression of 3 groups of genes involved in plant defense responses are discussed in relation to different signal transduction pathways.

Anti-Infective Agents↗
PubMed1983

An extended secondary structure model for the TMV assembly origin, and its correlation with protection studies and an assembly defective mutant.

Recognition of the unique internal assembly origin on tobacco mosaic virus (TMV) RNA by the disk aggregate of the viral coat protein probably involves an extended region of the RNA (larger than that coated by a single disk) folded into a specific conformation. A secondary structure model is proposed for the RNA preferentially coated by limiting amounts of coat protein disks on the basis of partial nuclease digestion data. Part of this sequence can form three symmetrically spaced hairpins with marginally stable base paired sequences at the tips of the stems. The pattern of progressive protection of the RNA from nuclease attack during assembly suggests that these three hairpins are successively coated by the first three disks to add. The spacing of these hairpins is identical to that of three hairpins in the pseudo assembly origin (part of the coat protein gene homologous to the assembly origin). In Ni 2519, a TMV mutant whose assembly is defective at high temperature because it can no longer discriminate between the true and pseudo assembly origins, a point mutation has occurred near the tip of the third metastably base paired stem of the true assembly origin which would disrupt its structure and alter one copy of a repeated heptanucleotide. This suggests an important role for the ordered and cooperative recognition of successive loops in determining the specificity of assembly.

Journal Article↗