| reason for non-aphid transmissibility in a strain of kalanchoë mosaic potyvirus. | kalanchoë mosaic potyvirus (kmv) is transmitted by aphids in a nonpersistent manner. after multiple mechanical inoculations, a non-aphid-transmissible (nat) variant appeared. addition of purified helper component (hc) from potato virus y-infected plants did not restore the aphid transmissibility of purified kmv-nat. comparison of the nucleotide sequence in the n-terminal half of the coat protein gene of kmv-nat with that of an aphid-transmissible (at) kmv strain revealed a single nucleotide diff ... | 1995 | 8808336 |
| three-dimensional model of the potyviral genome-linked protein. | the full sequence of the genome-linked viral protein (vpg) cistron located in the central part of potato virus y (common strain) genome has been identified. the vpg gene codes for a protein of 188 amino acids, with significant homology to other known potyviral vpg polypeptides. a three-dimensional model structure of vpg is proposed on the basis of similarity of hydrophobic-hydrophilic residue distribution to the sequence of malate dehydrogenase of known crystal structure. the 5' end of the viral ... | 1996 | 8901548 |
| sequence polymorphism in the 5'ntr and in the p1 coding region of potato virus y genomic rna. | potato virus y (pvy) the type member of the genus potyvirus, occurs world-wide as isolates which differ in host range and the type of symptoms caused. the sequences of a 5' segment of viral rna overlapping the 5' non-translated region (5'ntr) alone (ten isolates) or the 5'ntr and the adjacent p1 coding region (eight isolates) were established. these data were used to quantify the polymorphism in the 5'-terminal part of the pvy genome. nucleotide sequence identity between isolates ranged from 66- ... | 1995 | 9049340 |
| transgenic accumulation of two plant virus coat proteins on a single self-processing polypeptide. | an expression cassette based on the highly specific tobacco etch potyvirus (tev) nuclear inclusion (nia) proteinase has been developed to produce multiple proteins through the translation of a single self-processing polypeptide. gene constructs encoding tev nia, the tobacco mosaic tobamovirus (tmv) coat protein (cp) and the soybean mosaic potyvirus (smv) cp were used to develop transgenic tobacco plants. proper processing of the multifunctional polypeptide was demonstrated, leading to accumulati ... | 1997 | 9225054 |
| potato virus a detection by reverse transcription-polymerase chain reaction. | simple and reliable procedure for sample preparation and reverse transcription-polymerase chain reaction (rt-pcr) detection of potato virus a (pva) is described. pva-specific primers used in the rt-pcr defined a target sequence of 321 bp and did not produce amplification product(s) with potato virus y. | 1998 | 9770075 |
| amplification and cloning of a long rna virus genome using immunocapture-long rt-pcr. | a rapid and easy method was developed in order to amplify long fragments of the genome of potato virus y (pvy), a virus possessing a 10-kb genomic rna. the method of immunocapture-rt-pcr was adapted, by using thermostable dna polymerases with proofreading activity and the proper buffers and cycles, to amplify almost the whole genome of pvy in two fragments (5.6 and 4.3 kb) without purifying virions nor viral rna. both fragments were cloned subsequently and their ends sequenced. the method is app ... | 1997 | 9220402 |
| complex formation determines the activity of ribozymes directed against potato virus yn genomic rna sequences. | a ribozyme was synthesized against a conserved region in the rna-dependent rna-polymerase encoding cistron of the important plant pathogen potato virus y (pvy). this ribozyme was shown to cleave pvy-specific rna-transcripts efficiently in vitro, with up to 95% of the substrate rna being cleaved within 2 h incubation at 37 degrees c. a second ribozyme, designed with much shorter viral complementary arms in an attempt to optimize the efficiency of the cleavage reaction, surprisingly failed to clea ... | 1993 | 8460529 |
| expression and assembly of the potato virus y (pvy) coat protein (cp) in escherichia coli cells. | a clone harboring the full-length cdna of potato virus y in a lambda-dash vector under the control of a t7 promoter was introduced into escherichia coli carrying the t7-rna-polymerase gene on a plasmid. the viral coat protein was expressed and the product was of the same size as the corresponding mature protein in infected plants. immunoelectronmicroscopy of transfected cell extracts revealed virus-like particles, indicating that the proteins involved in its processing and the viral coat protein ... | 1993 | 8493811 |
| signal for potyvirus-dependent aphid transmission of potato aucuba mosaic virus and the effect of its transfer to potato virus x. | a british isolate of potato aucuba mosaic potexvirus (pamv) was transmitted by aphids (myzus persicae) which had fed previously on a source of potato y potyvirus (pvy). nucleotide sequence analysis of the pamv coat protein gene indicated that amino acid residues 14 to 16 from the n terminus of the coat protein have the sequence dag, which is also found in the coat proteins of potyviruses and is required for their aphid transmissibility. a recombinant virus isolate (txpa7) was produced in which a ... | 1993 | 8336116 |
| mutational analysis of the potato virus y 5' untranslated region for alteration in translational enhancement in tobacco protoplasts. | the 185 nucleotide 5' untranslated region (5'utr) of potato virus y ordinary strain (pvy-o) showed translation-enhancing activity on the beta-glucuronidase (gus) gene in tobacco protoplasts. mutational analysis of the 5'utr was done to find sequence motifs necessary for the enhancement. deletions within the 1-130 nucleotide region of 5'utr stimulated the gus expression in some cases, while the gus activity declined with deletions in the 131-185 nucleotide region. the results indicated that the l ... | 1997 | 9438996 |
| a hypersensitive response-like mechanism is involved in resistance of potato plants bearing the ry(sto) gene to the potyviruses potato virus y and tobacco etch virus. | potato plants carrying the ry(sto) gene from solanum stoloniferum are extremely resistant to a number of potyviruses, but it is not known at what stage of infection the resistance is expressed. the resistance may be due to ry(sto) or to a closely linked gene. in this investigation, we used potato virus y (pvy) and a tobacco etch virus construct that encodes beta-glucuronidase (tev-gus) to monitor virus infections of potato plants. systemic spread of either virus in resistant potato plants was no ... | 1998 | 9460939 |
| simultaneous detection of cucumber mosaic virus, tomato mosaic virus and potato virus y by flow cytometry. | the simultaneous detection is described of cucumber mosaic virus (cmv), potato virus y (pvy) and tomato mosaic virus (tomv) by flow cytometry. extracts from leaves of healthy and cmv or pvy infected plants were incubated with latex particles, each with a diameter of 3 microm. extracts from tomv infected or uninfected plants, however, were incubated with particles, each with a diameter of 6 microm. beads were washed and incubated in succession with primary and secondary antibodies, the latter lab ... | 1997 | 9504759 |
| expression of a cdna encoding phytolacca insularis antiviral protein confers virus resistance on transgenic potato plants. | to develop an antiviral agent and virus-resistant plants, a cdna clone encoding phytolacca insularis antiviral protein (pip) was isolated from a cdna library constructed with poly(a)+ rna purified from leaves of p. insularis. the pip cdna contains an open reading frame encoding 307 amino acids. the deduced amino acid sequence includes a putative signal sequence of 22 amino acids at the n-terminus. the amino acid sequence of pip shares 84% homology with that of the pokeweed antiviral protein (pap ... | 1997 | 9509425 |
| a simplified procedure for the subtractive cdna cloning of photoassimilate-responding genes: isolation of cdnas encoding a new class of pathogenesis-related proteins. | transgenic tobacco plants (ppa-1) constitutively expressing escherichia coli pyrophosphatase behind the 35s camv promoter accumulate high levels of soluble sugars in their leaves [27]. these plants were considered a tool to study adaptation of leaves to photoassimilate accumulation at the molecular level. by differential hybridization of a subtractive library enriched for transcripts present in the transgenic plants 12 different cdnas were isolated. by sequence analysis four cdnas could be ident ... | 1995 | 8555446 |
| separation of slovenian isolates of pvy(ntn) from the north american isolates of pvy(n) by a 3-primer pcr. | the potato tuber ringspot necrosis isolate of potato virus y (pvy(ntn)) is a recently recognized and highly aggressive isolate of the pvy(n) group of strains. in order to screen specifically sources of resistance to pvy(ntn) a method to separate pvy(ntn) from pvy(n) is needed. to achieve this, 61 isolates from 13 imported and locally developed potato cultivars in slovenia were studied. on the basis of the reactions in indicator plants nicotiana tabacum cv. samsun and solanum brachycarpum and wit ... | 1998 | 9628222 |
| expression of the "helper component" protein of potato virus y (pvy) in e. coli: possible involvement of a third protease. | transmission of potyviruses by aphids depends on the presence of a virus encoded helper-component protein (hc) that also exhibits protease activity. hc was expressed in e. coli from two types of clones: a full-length cdna clone of pvy and two 5' end clones containing the first three cistrons (3.6-3.7 kbp). the clones derived from the 5' end of pvy expressed hc of the size of the mature component. other proteins reacting with antibodies to hc were also observed, and their sizes corresponded with ... | 1993 | 8367942 |
| cloning and sequencing of potato virus y (hungarian isolate) genomic rna. | a sequence of 9703 nucleotides (nt) is reported for the genomic rna of potato virus y (hungarian isolate, pvy-h), which causes necrotic rings around the buds on the tubers and mottling of leaves. the sequence contains one large open reading frame of 3061 amino acids (aa), a noncoding region of 189 nt at the 5' end and a 330-nt 3' nontranslated region. the nt sequence and the predicted aa sequence of the polyprotein of pvy-h were analysed pairwise with the only available complete sequence of pvy ... | 1993 | 8428653 |
| virus-induced cell death in plants expressing the mammalian 2',5' oligoadenylate system. | the major components of the 2-5a system, responsible for the mammalian interferon-induced antiviral response, are the 2',5' oligoadenylate synthetase (2-5aase) and 2',5' oligoadenylate (2-5a) dependent ribonuclease (rnase l). transgenic tobacco plants expressing these two enzyme activities were produced by crossing the transgenic plants expressing rnase l with those expressing 2-5aase. the double transgenic plants showed complete resistance against cucumber mosaic virus (cmv), infection with nec ... | 1996 | 9634822 |
| potato virus y group c isolates are a homogeneous pathotype but two different genetic strains. | potato virus y group c isolates (pvyc) have been characterized according to biological, molecular and genetic criteria. two genetic strains, pvyc1 and pvyc2, were identified on the basis of genetic distances (among them and other pvy strains), host range (ability or inability to infect pepper), mab response (elisa recognition with mab 10e3) and coat protein processing site. some characteristics, such as aphid transmission and elisa using other mabs, did not correlate with classification into the ... | 1998 | 9714255 |
| strain specific recombinant antibodies to potato virus y potyvirus. | single chain fv antibody fragments have been selected from a synthetic phage-antibody library following three and four rounds of affinity selection with purified potato virus y, common strain (pvy(o)). the selected fragments were highly specific for pvy and detected seven out of nine isolates of pvy(o) whilst failing to detect three isolates of pvy(n) and 12 isolates of pvy(ntn). nucleotide sequence of the scfv genes showed the variable heavy fragments belonged to the human vh4 family, whilst th ... | 1998 | 9779619 |
| localization of the p1 protein of potato y potyvirus in association with cytoplasmic inclusion bodies and in the cytoplasm of infected cells. | the n-terminal p1 proteinase of potato virus y (ordinary strain group isolate pvy-o) was expressed in e. coli. antiserum was raised against the expressed protein and used to detect the viral proteins in infected tobacco leaf tissue by western blotting and by electron microscopy with immunogold labelling. in the immunogold localization studies p1 protein was detected in association with the cytoplasmic inclusion bodies characteristic of pvy infections and in the cytoplasm of the infected plant ce ... | 1998 | 9780035 |
| a strain-type clustering of potato virus y based on the genetic distance between isolates calculated by rflp analysis of the amplified coat protein gene. | potato virus y (pvy) isolates have been classified into genetic strains by a host-independent criterion using a molecular typing method. the method used extracts from infected tissue, and included immunocapture-rt-pcr-rflp analysis using 5 different restriction endonucleases (dde i, eco rv, hinf i, rsa i and taq i). genetic distances between the different pvy "restrictotypes" were calculated and used to define the pvy genetic strains. three main clusters were found: pvyo, pvyn, and non-potato pv ... | 1996 | 9526547 |
| genetic engineering of potato for broad-spectrum protection against virus infection. | transgenic potato plants expressing mutant alleles of plrv orf4, the gene for the movement protein pr17 of this luteovirus, were generated for broad-range protection against virus infection. when tested for protection against infection by plrv, all transgenic lines showed a significant reduction of virus antigen. potato lines accumulating n- or c-terminally extended plrv pr17 mutant proteins were resistant to infection by the unrelated potato viruses pvy and pvx. transgenic lines that did not ex ... | 1996 | 9634829 |
| molecular characterization of coat protein genes of serologically distinct isolates of potato virus y necrotic strain. | the cost protein (cp) genes of two potato virus y necrotic isolates (n27 and a mutant strain n27-92), which differed in their reactivity to a monoclonal antibody (mab), were characterized. both isolates could be detected by mab 4e7, but mab vn295.5 selectively reacted to n27 and not to n27-92. the cp genes of both isolates coded for 267 amino acids with approximately 99.0% identity at both the nucleotide and the amino acid levels. nucleotide sequence comparison indicated five substitutions in n2 ... | 1997 | 9246744 |
| resistance in plants transformed with the p1 or p3 gene of tobacco vein mottling potyvirus. | tobacco plants were transformed with genes encoding the tobacco vein mottling potyvirus (tvmv) p1 or p3 protein. when compared with vector-transformed or p1 transgenic lines, seedlings of p3 transgenic lines (except a low expressor line) developed poorly, suggesting a detrimental effect of p3 on the plant. all p1 and p3 transgenic lines were protected against the homologous tvmv strain and showed variable proportions of two resistance phenotypes: asymptomatic plants or symptomatic plants that re ... | 1998 | 9820159 |
| rflp mapping of the whole genome of ten viral isolates representative of different biological groups of potato virus y. | ten pvy isolates representative of four pvy groups (yn, yntn, yn-w, yo), differing by their ability to induce reactions of vein necrosis on tobacco and tuber necrosis on potato, were studied in order to research the regions of the viral genome involved in these necrosis phenomena. the whole genome of these isolates was amplified in two fragments (4,063 and 5,670 nucleotides) and was subjected to a restriction fragment length polymorphism (rflp) study. in the first 4,063 nucleotides of the pvy ge ... | 1998 | 9856095 |
| sequencing and characterization of the coat protein and 3' non-coding region of a new sweet potato potyvirus. | a cdna library was constructed from viral genomic rna purified from sweet potato plants affected by "sweet potato chlorotic dwarf disease" in an attempt to clarify the etiology of this viral complex in argentina. by sequence analysis, some of the obtained clones were found to belong to sweet potato feathery mottle potyvirus (spfmv), to a closterovirus and to a new potyvirus. a cdna clone of 1,103 bp representing the coat protein cistron and 3' non-coding region of the newly identified potyvirus ... | 1997 | 9672624 |
| infectious in vivo and in vitro transcripts from a full-length cdna clone of pvy-n605, a swiss necrotic isolate of potato virus y. | a full-length cdna clone of the potato virus y (pvy) genome was obtained after cloning difficulties in escherichia coli were overcome. these difficulties were mainly due to the expression of the ci gene from upstream prokaryotic promoter-like elements within the pvy genome. to overcome this problem, pvy cdna was maintained in two subclones which were ligated before infection. a plasmid in which these two fragments were contained could be propagated in some e. coli strains but was unstable and yi ... | 1997 | 9400962 |
| synthesis of full-length potyvirus cdna copies suitable for the analysis of genome polymorphism. | new methods facilitating the synthesis and amplification of full-length cdna copies of single-stranded viral rna genomes have been developed. a method is described for the efficient purification of potyviral rna and total rna from infected plants and it is shown that they can serve as templates for the efficient synthesis of a full-length, 10 kb long, genomic cdna. two different reverse transcriptases were used (amv-rt and mmlv-rt); only the first reverse transcriptase produced a good quality, f ... | 1997 | 9300384 |
| viral pathogenicity determinants are suppressors of transgene silencing in nicotiana benthamiana. | post-transcriptional gene silencing (ptgs) of a green fluorescent protein (gfp) transgene is suppressed in nicotiana benthamiana plants infected with potato virus y (pvy) or with cucumber mosaic virus (cmv), but not in plants infected with potato virus x (pvx). by expressing pvy and cmv-encoded proteins in a pvx vector we have shown that the viral suppressors of gene silencing are the hcpro of pvy and the 2b protein of cmv. the hcpro acts by blocking the maintenance of ptgs in tissues where sile ... | 1998 | 9822616 |
| mutations in the potyvirus helper component protein: effects on interactions with virions and aphid stylets. | mutations of k --> e in the highly conserved 'kitc' motif of the potyvirus helper component (hc) protein result in loss of hc function in aphid transmission, presumably because of inability to interact with virions, stylets or both. in this study we show that hc of potato virus c (pvc), a naturally occurring variant of potato virus y (pvy) that has the k --> e mutation, lacks the ability to be retained in stylets, whereas pvy hc is retained. the k --> e mutation in either pvc or a site-directed ... | 1998 | 9880030 |
| induction of antibodies to plant viral proteins by dna-based immunization. | dna-based immunization is a promising new technique for generating antibodies in laboratory animals for diagnostic purposes in biological science. the main advantages are the elimination of time and labor and the technically demanding steps of antigen purification. the dna sequence of the protein of interest, cloned in a suitable in vivo expression vector that is administered intramuscularly or intradermally, is sufficient to induce an immune response in animals. we report the induction of antib ... | 1997 | 9255730 |
| effect of mutations within the cys-rich region of potyvirus helper component-proteinase on self-interaction. | the first approximately 60 amino acids of the n-terminal part of the potyvirus helper component-proteinase (hc-pro) include highly conserved residues comprising a cys-rich region. in the present study, the domain in potato virus y sufficient for self-interaction was mapped using the yeast two-hybrid system to the 83 n-terminal amino acids of hc-pro. mutations in the conserved his and two cys residues within the cys-rich region have a strong debilitating effect on self-interaction when introduced ... | 1999 | 10580041 |
| transgenic plants expressing potato virus x orf2 protein (p24) are resistant to tobacco mosaic virus and ob tobamoviruses. | the p24 protein, one of the three proteins implicated in local movement of potato virus x (pvx), was expressed in transgenic tobacco plants (nicotiana tabacum xanthi d8 nn). plants with the highest level of p24 accumulation exhibited a stunted and slightly chlorotic phenotype. these transgenic plants facilitate the cell-to-cell movement of a mutant of pvx that contained a frameshift mutation in p24. upon inoculation with tobacco mosaic virus (tmv), the size of necrotic local lesions was signific ... | 1998 | 9420280 |
| rna-dna interactions and dna methylation in post-transcriptional gene silencing. | post-transcriptional gene silencing (ptgs) is a homology-dependent process that reduces cytoplasmic rna levels. in several experimental systems, there is also an association of ptgs with methylation of dna. to investigate this association, we used plants carrying a transgene encoding the green fluorescent protein (gfp). gene silencing was induced using potato virus x rna vectors carrying parts of the coding sequence or the promoter of the gfp transgene. in each instance, homology-based, rna-dire ... | 1999 | 10590159 |
| deletion of a large genomic segment in tobacco varieties that are resistant to potato virus y (pvy). | recessive alleles (va, va1, va2, etc) of the tobacco va locus confer resistance to potato virus y (pvy). to elucidate the mechanism underlying this resistance, we attempted to identify randomly amplified polymorphic (rapd) markers that reveal polymorphism between two nearly isogenic lines (nils) that differ in their susceptibility to pvy. using each of 500 primers and 800 pairs of primers, we identified over 100 rapd fragments that differed between the nils. we applied these rapd primers or prim ... | 1999 | 10628866 |
| expression of a luteoviral movement protein in transgenic plants leads to carbohydrate accumulation and reduced photosynthetic capacity in source leaves. | elucidating the role of viral genes in transgenic plants revealed that the movement protein (mp) from tobacco mosaic virus is responsible for altered carbohydrate allocation in tobacco and potato plants. to study whether this is a general feature of viral mps, the movement protein mp17 of potato leafroll virus (plrv), a phloem-restricted luteovirus, was constitutively expressed in tobacco plants. transgenic lines were strongly reduced in height and developed bleached and sometimes even necrotic ... | 1997 | 9418046 |
| mutations in the coat protein gene of plum pox virus suppress particle assembly, heterologous encapsidation and complementation in transgenic plants of nicotiana benthamiana. | two different motifs in the coat protein (cp) of plum pox virus (ppv) (r(3015)q(3016), d(3059)) were mutated by replacing the respective amino acids with others possessing different chemical properties. the mutated cp genes were introduced into an infectious full-length clone of ppv (p35ppv-nat) to investigate their influence on systemic infection of transgenic wild-type ppv cp-expressing and non-transgenic plants of nicotiana benthamiana. all mutants failed to establish systemic infections in n ... | 2000 | 10675394 |
| aphid transmission studies using helper component proteins of potato virus y expressed from a vector derived from potato virus x. | the genes encoding the helper component (hc) proteins of two strains of potato virus y (pvy) were cloned and the proteins expressed from a vector derived from potato virus x (pvx). the expressed hc contained six n-terminal histidine residues to facilitate purification by metal affinity chromatography. approximately 2-4 microg/g of purified hc was obtained from leaves of nicotiana benthamiana plants systemically infected by recombinant pvx. preparations of the hc protein derived from pvy ordinary ... | 2000 | 10725440 |
| development of a caps marker for the pvr4 locus: a tool for pyramiding potyvirus resistance genes in pepper. | the pvr4 resistance gene in pepper confers a complete resistance to the three pathotypes of potato virus y (pvy) and to pepper mottle virus (pepmov). in order to use this gene in a marker-assisted selection (mas) program and to permit the pyramiding of several potyvirus resistance genes in the same cultivar, tightly linked amplified fragment length polymorphism (aflp) markers were obtained by the bulked segregant analysis method. eight linked aflp markers were mapped in an interval from 2.1 +/- ... | 1999 | 10659777 |
| affinity purification of hc-pro of potyviruses with ni2+-nta resin. | the hc-pro of zucchini yellow mosiac virus (zymv) was found to bind to ni2+-nta resin with or without his-tagging. the binding stringency was similar to that observed in proteins with a zinc finger motif like the hc-pro. using this characteristic we developed an efficient and rapid method (2-3 h) for purification of the hc-pro of several potyviruses. a dominant protein of about 150 kda was extracted and identified as the hc-pro of zymv by means of immunoblotting. about 150 microg of hc-pro were ... | 1998 | 9923736 |
| complementation of the movement-deficient mutations in potato virus x: potyvirus coat protein mediates cell-to-cell trafficking of c-terminal truncation but not deletion mutant of potexvirus coat protein. | the cell-to-cell movement of the gus-tagged potato virus x (pvx) coat protein (cp) movement-deficient mutant was restored by potyviral cps of potato virus a (pva) and potato virus y (pvy) in nicotiana benthamiana leaves in transient cobombardment experiments. viral cell-to-cell movement of pvx cp mutant was complemented in nicotiana tabacum cv. sr1 transgenic plants expressing pvy cp: pvx rna and polymerase were detected in the pvx cp mutant-inoculated leaves of transgenic plants. these findings ... | 2000 | 10772977 |
| the use of cysteine proteinase inhibitors to engineer resistance against potyviruses in transgenic tobacco plants. | as the processing mechanism of all known potyviruses involves the activity of cysteine proteinases, we asked whether constitutive expression of a rice cysteine proteinase inhibitor gene could induce resistance against two important potyviruses, tobacco etch virus (tev) and potato virus y (pvy), in transgenic tobacco plants. tobacco lines expressing the foreign gene at varying levels were examined for resistance against tev and pvy infection. there was a clear, direct correlation between the leve ... | 1999 | 10585723 |
| recessive and dominant genes interfere with the vascular transport of potato virus a in diploid potatoes. | resistance to potato virus a (pva) was examined in a diploid cross involving solanum tuberosum subsp. andigena as a resistance source. hypersensitive resistance (hr) to pva cosegregated with extreme resistance (er) to potato virus y conferred by the dominant gene ry(adg) on chromosome xi. hence, hr to pva was controlled by a novel, dominant resistance gene closely linked to ry(adg), or ry(adg) recognized both viruses but conferred a different type of resistance to each virus. the hr prevented sy ... | 2000 | 10755303 |
| partial antigenic characterization of different potato virus y ntn strain isolates. | eight isolates of potato virus y ntn strain (pvy-ntn) of different origin were studied by means of monoclonal antibodies (mabs) in non-competitive and competitive enzyme-linked immunosorbent assay (elisa), and by immunoblot analysis of the viral coat protein (cp). as the mabs reacted with the denatured viral cp, their epitopes must be continuous. the elisa data demonstrate that the epitopes are topologically different. the epitopes may be located on the n-terminal part of cp as showed its partia ... | 1999 | 10825930 |
| transgenic resistance to pvy(o) associated with post-transcriptional silencing of p1 transgene is overcome by pvy(n) strains that carry highly homologous p1 sequences and recover transgene expression at infection. | resistance to potato virus y (pvy) has been obtained in our previous studies through expression of the pvy p1 gene in sense or antisense orientation in potato cv. pito. in the present study, the mechanism and strain specificity of the resistance were analyzed. several features including low steady-state p1 mrna expression in the resistant p1 plants indicated that resistance was based on post-transcriptional gene silencing (ptgs). resistance was specific to pvy(o) isolates, the pvy strain group f ... | 2000 | 10755299 |
| duplex rt-pcr: reagent concentrations at reverse transcription stage affect the pcr performance. | test conditions for the simultaneous detection of potato leafroll virus (plrv) and potato virus y (pvy) in dormant tubers and leaves by reverse transcription-polymerase chain reaction (rt-pcr) were optimized. various factors optimized at the reverse transcription (rt) stage rather than at the amplification (pcr) stage affected the outcome. in the simplex rt-pcr a onefold dntps concentration (0.5 mm) was sufficient in yielding a plrv or pvy band. in contrast, the duplex rt-pcr required a minimum ... | 2000 | 10785287 |
| an ry-mediated resistance response in potato requires the intact active site of the nia proteinase from potato virus y. | ry confers extreme resistance to all strains of potato virus y (pvy). to identify the elicitor of the ry-mediated resistance against pvy in potato, we expressed each of the pvy-encoded proteins in leaves of pvy-resistant (ry) and -susceptible (ry) plants. for most of the proteins tested, there was no evident response. however, when the nia proteinase was expressed in leaves of ry plants, there was a hypersensitive response (hr). proteinase active site mutants failed to induce the ry-mediated res ... | 2000 | 10972891 |
| a hypercycle theory of proliferation of viruses and resistance to the viruses of transgenic plant. | a set of dynamical equations for the proliferation of two typical viruses tmv and pvy has been derived from the reaction equations describing their replication, assembly and translation. these equations can be seen as the generalization of hypercycle theory to the system. the quantitative explanation on the phenomena of proliferation of plant virus and the mechanism of resistance to the disease of transgenic plant is offered. the phenomenon of specific cessation of minus-strand rna accumulation ... | 2000 | 10816368 |
| some epidemiological approaches to the control of aphid-borne virus diseases in seed potato crops in northern europe. | an account is given of progress during the last 30 years in knowledge of the epidemiology of diseases caused by aphid-borne viruses in seed potato production areas of northern europe. during this period, potato leafroll virus (plrv) and strains of potato virus y (pvy(o), pvy(n)) were consistently the most prevalent and harmful. the main factors influencing spread involve the amount of initial virus inoculum in seed crops, agricultural practices in relation to seed potato production, the status o ... | 2000 | 11137160 |
| barrier crops as a cultural control measure of non-persistently transmitted aphid-borne viruses. | barrier crops have been used since the early 1950s as a cultural control strategy for reducing the spread of non-persistently transmitted aphid-borne viruses. since then, this strategy has been investigated by several authors, resulting in a wide range of divergent conclusions on its effectiveness. in a series of field and laboratory experiments carried out in central spain during 1995-1998, we investigated the efficacy and mode of action of various barrier crops for reducing the spread of potat ... | 2000 | 11137174 |
| a novel usage of random primers for multiplex rt-pcr detection of virus and viroid in aphids, leaves, and tubers. | a multiplex reverse transcription polymerase chain reaction (m-rt-pcr) was developed for the simultaneous detection of five potato viruses and a viroid. the synthesis of cdnas used for amplification was primed by hexanucleotides (random primers, rp). an rna extraction procedure employing dnase i, is routinely used to isolate potato viruses and viroid (potato virus s, pvs; potato leafroll virus, plrv; potato virus x, pvx; potato virus a and y, pva, pvy; and potato spindle tuber viroid, pstvd) fro ... | 2001 | 11164484 |
| comparative genetics of disease resistance within the solanaceae. | genomic positions of phenotypically defined disease resistance genes (r genes) and r gene homologues were analyzed in three solanaceous crop genera, lycopersicon (tomato), solanum (potato), and capsicum (pepper). r genes occurred at corresponding positions in two or more genomes more frequently than expected by chance; however, in only two cases, both involving phytophthora spp., did genes at corresponding positions have specificity for closely related pathogen taxa. in contrast, resistances to ... | 2000 | 10835406 |
| analysis of variability of p1 gene region of n strain of potato virus y using temperature-gradient gel electrophoresis and dna heteroduplex analysis. | reaction conditions specific for reverse taranscription-polymerase chain reaction (rt-pcr) of potato virus y strain ntn (pvyntn) were used to amplify a 394 bp fragment of the p1 gene from selected pvy isolates with the aim to study the pvy variability within this genomic region. the p1 gene fragment from the nicola isolate (nicola p1/1 clone) was sequenced and characterized by temperature-gradient gel electrophoresis (tgge). the nicola p1/1 clone differed from that from the hungarian isolate by ... | 2000 | 10989691 |
| transgenic or plant expression vector-mediated recombination of plum pox virus. | different mutants of an infectious full-length clone (p35ppv-nat) of plum pox virus (ppv) were constructed: three mutants with mutations of the assembly motifs rq and df in the coat protein gene (cp) and two cp chimeras with exchanges in the cp core region of zucchini yellow mosaic virus and potato virus y. the assembly mutants were restricted to single infected cells, whereas the ppv chimeras were able to produce systemic infections in nicotiana benthamiana plants. after passages in different t ... | 2000 | 10906199 |
| potyvirus helper component-proteinase self-interaction in the yeast two-hybrid system and delineation of the interaction domain involved. | using the yeast two-hybrid system, a screen was performed for possible interactions between the proteins encoded by the 5' region of potyviral genomes [p1, helper component-proteinase (hc-pro), and p3]. a positive self-interaction involving hc-pro was detected with lettuce mosaic virus (lmv) and potato virus y (pvy). the possibility of heterologous interaction between the hc-pro of lmv and of pvy was also demonstrated. no interaction involving either the p1 or the p3 proteins was detected. a ser ... | 1999 | 10329571 |
| patterns of phenylpropanoids in non-inoculated and potato virus y-inoculated leaves of transgenic tobacco plants expressing yeast-derived invertase. | the patterns of secondary metabolites in leaves of yeast invertase-transgenic tobacco plants (nicotiana tabacum l. cv. samsun nn) were analyzed. plants expressing cytosolic yeast-derived invertase (cytinv) or apoplastic (cell wall associated) yeast invertase (cwinv) showed a characteristic phytochemical phenotype compared to untransformed controls (wild-type plants). the level of phenylpropanoids decreased in the cytinv plants but increased in the cwinv plants, which showed an induced de novo sy ... | 2001 | 11281130 |
| virus-specific spatial differences in the interference with silencing of the chs-a gene in non-transgenic petunia. | potyviruses, such as potato virus y and tobacco etch virus, as well as cucumber mosaic cucumovirus, interfere with post-transcriptional gene silencing (ptgs). when redstar-type petunia hybrida cultivars, whose flowers have alternating white and pigmented sectors, were infected with these viruses, each virus induced a different pattern of restoration of floral anthocyanin pigmentation. local reversion to coloured phenotypes in the white sectors, which occurred through interference with ptgs of th ... | 2001 | 11297699 |
| development of a multiplex amplidet rna for the simultaneous detection of potato leafroll virus and potato virus y in potato tubers. | a novel isothermal multiplex amplidet rna system is described for the simultaneous amplification and detection of potato leafroll virus (plrv) and potato virus y (pvy) in seed potatoes. the risk of contamination by carry-over during diagnostic screening is eliminated by performing the reaction in a single closed tube. the viruses present in a sample are identified using differently coloured molecular beacons directed to a selected virus-specific sequence within the amplicon formed during amplifi ... | 2001 | 11311350 |
| compositional analysis of tubers from insect and virus resistant potato plants. | genetically modified potato plants that are resistant to the colorado potato beetle, plus either the potato leaf roll virus or potato virus y, have recently been commercialized. as part of the safety assessment for plants produced by modern biotechnology, the composition of the food/feed must be compared to that of the food/feed produced by an equivalent plant variety from a conventional source. the composition of important nutritional and antinutritional factors in tubers produced by virus- and ... | 2000 | 11312768 |
| gene silencing-mediated resistance in transgenic tobacco plants carrying potato virus y coat protein gene. | unlike other pathogens, plant viruses are hardly controlled by chemical agents. potato virus y (pvy) is distributed around the world, and causes a great loss economically. in an attempt to minimize the damage by viruses, the pvy coat protein (cp) gene was introduced into tobacco by agrobacterium-mediated transformation. a significant proportion of the transgenic plants displayed resistance to pvy and showed substantially decreased cp transgene expression at both protein and steady-state mrna lev ... | 1999 | 10515600 |
| virus strain discrimination using recombinant antibodies. | most routine testing for plant viruses is currently carried out using monoclonal and polyclonal antibodies. traditional methods of antibody production however can be time consuming and require the use of expensive cell culture facilities. recombinant antibody technology however is starting to make an impact in this area, enabling the selection of antibody fragments in a few weeks compared with the many months associated with traditional methods and requires only basic microbiological facilities. ... | 2000 | 11360835 |
| nucleotide sequences of 5'-terminal parts of coat protein genes of various isolates of ntn strain of potato virus y. | sequences of the first 300 nucleotides of coat protein (cp) genes of 7 isolates of ntn strain of potato virus y (pvy, pvy(ntn)) were determined and compared with analogous published sequences of various isolates and strains of pvy. the sequence identity among the sequenced isolates ranged from 96 to 100%. the differences were found at different positions. the nucleotide sequence of this part of cp gene seems to be very conservative among the isolates tested that means that pvy(ntn) is the evolut ... | 2001 | 11394579 |
| differentiating pvy(ntn) from pvy(n) by annealing to reference rna transcripts. | a method for the differentiation of virus strains based on the shift in electrophoretic mobility of partially annealed rna transcripts is described. oppositely oriented rna transcripts of the ntn- and n-strains of pvy, complementary at their 3'-end variable (strain-specific) region, were annealed to form a partial duplex which moved more slowly in gel than heterologous (ntn+n) unpaired transcripts. thus, the two virus strains could be identified by annealing to a known reference transcript. the ... | 2001 | 11483223 |
| molecular characterization of a new potyvirus infecting sunflower. | we have sequenced 1873 nucleotides from the 3'-end region of a sunflower potyvirus genome including the 3'-nib protein coding region (813 nucleotides), the entire coat protein coding region (807 nucleotides) and 3'-ncr (253 nucleotides), excluding the poly (a) tail. amino acids identity of the whole cp between the sunflower virus and potyvirus members ranged from 49.5% (scmv) to 81.5% (pvy-nsnr), and the core ranged from 55% (tvmv) to 87% (pvy-nsnr; pepmov). the 3'-ncr nucleotides showed 38.7% h ... | 2000 | 11205115 |
| coat protein gene-mediated resistance to potato virus a in transgenic plants is suppressed following infection with another potyvirus. | high levels of resistance to potato virus a (pva, genus potyvirus), indicated by absence of detectable infection in inoculated leaves, were attained in nicotiana benthamiana transformed with a construct expressing the pva 5'-untranslated region fused with the coat protein (cp)-encoding sequence. low steady-state levels of the transgene transcripts were detected. resistance was pva-specific and did not protect the plants against infection with potato virus y (pvy, genus potyvirus). consequently, ... | 2001 | 11514739 |
| constitutive expression of interferon-induced human mxa protein in transgenic tobacco plants does not confer resistance to a variety of rna viruses. | mxa is a key component in the interferon-induced antiviral defense in humans. after viral infections, mxa is rapidly induced and accumulates in the cytoplasm. the multiplication of many rna viruses, including all bunyaviruses tested so far, is inhibited by mxa. these findings prompted us to express mxa in plants in an attempt to create resistance to tospoviruses. here, we report the generation of transgenic tobacco plants that constitutively express mxa under the control of the 35 s cauliflower ... | 2000 | 11206971 |
| umbravirus gene expression helps potato leafroll virus to invade mesophyll tissues and to be transmitted mechanically between plants. | potato leafroll virus (plrv) was mechanically transmissible when inocula also contained the umbravirus pea enation mosaic virus-2 (pemv-2). in plants infected with plrv and pemv-2, plrv accumulated in clusters of mesophyll cells in both inoculated and systemically infected leaves. no transmissions were obtained by coinoculation with potato virus y, potato virus x (pvx), tobacco mosaic virus, or cucumber mosaic virus (cmv), although plrv was transmissible from mixtures with cmv(orf4) (a recombina ... | 2001 | 11485404 |
| inhibition of potato virus y nia activity: preparation of monoclonal antibody directed against pvy ni protein that inhibits cleavage of pvy polyprotein. | a partially purified nuclear inclusion (ni) fraction was obtained from tobacco plants infected by potato virus y (pvy). four monoclonal antibodies (mabs) were produced and characterized using this semipurified fraction as antigen. data showed that only one was directed against nia whereas two were directed against cytoplasmic inclusion (ci) protein and the last one against coat protein (cp). these results were due to the fact that the semipurified ni fraction was usually contaminated with ci and ... | 2001 | 11556707 |
| sense- and antisense-mediated gene silencing in tobacco is inhibited by the same viral suppressors and is associated with accumulation of small rnas. | antisense-mediated gene silencing (asgs) and posttranscriptional gene silencing (ptgs) with sense transgenes markedly reduce the steady-state mrna levels of endogenous genes similar in transcribed sequence. rnase protection assays established that silencing in tobacco plants transformed with plant-defense-related class i sense and antisense chitinase (chn) transgenes is at the posttranscriptional level. infection of tobacco plants with cucumber mosaic virus strain fn and a necrotizing strain of ... | 2001 | 11353866 |
| sodium sulphite inhibition of potato and cherry polyphenolics in nucleic acid extraction for virus detection by rt-pcr. | phenolic compounds from plant tissues inhibit reverse transcription-polymerase chain reaction (rt-pcr). multiple-step protocols using several additives to inhibit polyphenolic compounds during nucleic acid extraction are common, but time consuming and laborious. the current research highlights that the inclusion of 0.65 to 0.70% of sodium sulphite in the extraction buffer minimizes the pigmentation of nucleic acid extracts and improves the rt-pcr detection of potato virus y (pvy) and potato leaf ... | 2002 | 11684310 |
| a mosaic disease of senna hirsuta induced by a potyvirus in nigeria. | a virus inducing mosaic and severe leaf malformation, isolated from senna hirsuta in nigeria, was studied. the virus had a rather narrow host range, infecting a few species in caesalpinaceae, chenopodiaceae and fabaceae families. the virus was widespread in southern nigeria with prevalence ranging from 74% to 86.4% in some locations. it was transmitted mechanically and in a non-persistent manner by myzuspersicae, aphis craccivora and a. spiraecola. there was no evidence of transmission by seeds. ... | 2001 | 11719985 |
| [function of the leaky uga codon in ssrna plant virus genomes]. | the opal mutation (uga) at nucleotide 2670-2672 in the replicase gene of the attenuated tomato mosaic virus k (tomv-k) mainly contributes to the virus attenuation based on a series of studies on the viral attenuation mechanism. from analysis and comparison between the replicase gene mutation point of tomv-k and the related regions of all plant viruses containing the leaky uga, we have found that some characters, including the cgg motif, alpha-helix structure and some specific amino acids, are, p ... | 2001 | 11517596 |
| rt-pcr-elosa tests on pooled sample units for the detection of virus y in potato tubers. | a highly sensitive rt-pcr protocol able to detect potato virus y (pvy) in pooled sample units (tubers) was developed. pvy-specific primers selected in the coat protein gene were found to amplify a 359 bp fragment from diluted crude extract of infected tubers. for the detection of the amplification products, a colorimetric detection procedure in microtiter plates was established. the amplicons are hybridized between a covalently linked capture probe and a specific biotinylated detection probe elo ... | 2001 | 11164491 |
| detection of different strains of potato virus y and their mixed infections using competitive fluorescent rt-pcr. | a competitive fluorescent rt-pcr assay (cf rt-pcr) was developed for the rapid and reliable detection and discrimination of the two most common strains of potato virus y (pvy) found in potato (necrotic and ordinary). the assay incorporates two strain specific primers labelled with fluorescent labels, used in conjunction with a universal pvy primer. the strain specific primers compete for the same annealing site which further increases specificity. discrimination is conferred by the fluorescent l ... | 2001 | 11164498 |
| characterization of typical pepper-isolates of pvy reveals multiple pathotypes within a single genetic strain. | potato virus y (pvy) isolates originally coming from infected pepper plants, were biologically and genetically characterized, especially in comparison with pvy potato-isolates. pepper pvy isolates could be differentiated from potato isolates in their host range, aphid transmission efficiencies, mab serology, and genetic status. the genetic distances estimated for pvy pepper-isolates, based on their restrictotypes with five restriction enzymes and on their coat protein gene sequences, indicated t ... | 2001 | 11551647 |
| volatiles from potato plants infected with potato leafroll virus attract and arrest the virus vector, myzus persicae (homoptera: aphididae). | the influence of viral disease symptoms on the behaviour of virus vectors has implications for disease epidemiology. here we show that previously reported preferential colonization of potatoes infected by potato leafroll virus (genus polerovirus) (luteovirus) (plrv) by alatae of myzus persicae, the principal aphid vector of plrv, is influenced by volatile emissions from plrv-infected plants. first, in our bioassays both differential immigration and emigration were involved in preferential coloni ... | 2002 | 11886636 |
| development of a multiplex amplidet rna assay for simultaneous detection and typing of potato virus y isolates. | a multiplex amplidet rna assay was developed for the specific detection of potato virus y (pvy), and for the differentiation of the pvy(n), pvy(o/c) strains and the tuber necrotic isolates (pvy(ntn)). the assay is based on the generic amplification of a region within the coat protein coding region of all known pvy isolates by nucleic acid sequence-based amplification (nasba) and strain-specific detection by molecular beacons. pvy(ntn)-specific diagnosis is achieved by detecting pvy(n) and pvy(o) ... | 2002 | 11742655 |
| evidence for rna-mediated defence effects on the accumulation of potato leafroll virus. | in plants infected with potato leafroll virus (plrv), or other luteoviruses, infection is very largely confined to cells in the vascular system. even in tobacco plants transformed with plrv full-length cdna, in which all mesophyll cells should synthesize infectious plrv rna transcripts, only a minority of the mesophyll cells accumulate detectable amounts of virus. we have explored this phenomenon further by transforming a better plrv host, nicotiana benthamiana, with the same transgene, by super ... | 2001 | 11714988 |
| probable geographical grouping of pvy(n) and pvy(ntn) based on sequence variation in p1 and 5'-utr of pvy genome and methods for differentiating north american pvy(ntn). | an increasing number of countries in recent years have reported the occurrence of potato tuber necrotic ringspot disease (ptnrd), caused by tobacco veinal necrosis strain of potato virus y (pvy(n)), belonging to the sub-group tuber necrosis (pvy(ntn)). methods for the differentiation of pvy(ntn), based on primer sequences often detect isolates of european (eu) type but not the north american (na) type. to resolve this problem, the nucleotide sequence of 5'-untranslated region (5'-utr) and the p1 ... | 2002 | 12008009 |
| improved electrophoretic resolution of rna transcripts by specific homologous oligonucleotide gel retardation. | an improved procedure for the resolution of rna transcripts by electrophoretic gel retardation, mediated by annealing to specific homologous oligonucleotiedes is described. the n and ntn strains of pvy served as a model system. non-polymorphic but sequence-diverse rna transcripts were copied from pcr products of the two virus strains. the transcripts were resolved by gel electrophoresis, because of the differential retardation effect caused by the binding of strain-specific homologous oligonucle ... | 2001 | 11164912 |
| genomic variability in potato potyvirus y (pvy): evidence that pvy(n)w and pvy(ntn) variants are single to multiple recombinants between pvy(o) and pvy(n) isolates. | fourteen potato virus y (pvy) isolates representative of pvy(o), pvy(n), pvy(ntn) and pvy(n)w groups were characterised at genomic level. restriction fragment length polymorphism study (rflp) of each gene of these isolates and sequencing of the first 2700 nucleotides of two pvy(n)w isolates were performed. a mosaic structure was revealed in pvy(n)w and pvy(ntn) genomes, which showed either pvy(o) or pvy(n)-like sequences, depending on the particular gene. indeed, starting from the 5'-end, these ... | 2002 | 11890528 |
| transgenic plants expressing hc-pro show enhanced virus sensitivity while silencing of the transgene results in resistance. | nicotiana benthamiana plants were engineered to express sequences of the helper component-proteinase (hc-pro) of cowpea aphid-borne mosaic potyvirus (cabmv). the sensitivity of the transgenic plants to infection with parental and heterologous viruses was studied. the lines expressing hc-pro showed enhanced symptoms after infection with the parental cabmv isolate and also after infection with a heterologous potyvirus, potato virus y (pvy) and a comovirus, cowpea mosaic virus (cpmv). on the other ... | 2002 | 12206307 |
| interaction between potyvirus helper component-proteinase and capsid protein in infected plants. | monoclonal antibodies were raised against helper component-proteinase (hcpro) purified from plants infected with the potyvirus lettuce mosaic virus (lmv). these antibodies were used in a two-site triple antibody sandwich elisa assay together with polyclonal antibodies directed against purified virions. an interaction between hcpro and the viral coat protein (cp) was demonstrated in extracts of lmv-infected leaves, as well as for two other potyviruses, plum pox virus and potato virus y. the cp-hc ... | 2002 | 12075097 |
| systemic acquired resistance mediated by the ectopic expression of invertase: possible hexose sensing in the secretory pathway. | systemic acquired resistance (sar) has been reported to be associated with lesion-mimic mutants. tobacco plants expressing vacuolar and apoplastic yeast-derived invertase (vaclnv and cwlnv, respectively) develop spontaneous necrotic lesions similar to hypersensitive responses caused by avirulent pathogens. therefore, sar and metabolic alterations leading to the activation of defense-related responses were studied in these plants. defense-related gene transcripts, callose content, peroxidase acti ... | 1996 | 12239401 |
| correlation of viral rna biosynthesis with glucose-6-phosphate dehydrogenase activity and host resistance. | changes in glucose-6-phosphate dehydrogenase (g6p dh; ec 1.1.1.49) activity caused by infection of tobacco ( nicotiana tabacum l.) leaves with potato virus y (pvy), cucumber mosaic virus, potato virus x, tobacco rattle virus and turnip mosaic virus, the subcellular localisation of g6p dh isozymes in mesophyll protoplasts derived from healthy and pvy-infected tobacco leaves, as well as g6p dh control and the relationship of its isozymes with the degree of tobacco resistance to pvy multiplication, ... | 2002 | 12244453 |
| induction of a highly specific antiviral state in transgenic plants: implications for regulation of gene expression and virus resistance. | transgenic tobacco plants expressing either a full-length form of the tobacco etch virus (tev) coat protein or a form truncated at the n terminus of the tev coat protein were initially susceptible to tev infection, and typical systemic symptoms developed. however, 3 to 5 weeks after a tev infection was established, transgenic plants "recovered" from the tev infection, and new stem and leaf tissue emerged symptom and virus free. a tev-resistant state was induced in the recovered tissue. the resis ... | 1993 | 12271055 |
| ultra-violet irradiation of tobacco infected with potato virus y and the availability of virus to aphids. | | 1954 | 13144758 |
| immunocapture rt-pcr probing of potato virus y isolates. | twenty potato virus y (pvy) isolates were characterized. they represented two strains only, pvy(o) (three isolates) and pvy(n) (17 isolates). however, application of serological and molecular genetic methods led to a more complicated characterization. for example, five isolates induced necrotic symptoms on tobacco plants typical of pvy(n), despite reacting as pvy(o) serologically. moreover, the pvy isolates were not identical according to molecular genetic properties. typical pvy(ntn) pcr produc ... | 2002 | 12387496 |
| production of anti-virus, viroid plants by genetic manipulations. | many pathogenic plant viruses are rna viruses, which initiate production of double-stranded rna intermediates when they replicate in host plant cells. introduction of double-stranded rna-specific ribonucleases such as the schizosaccharomyces pombe derived pac i protein and animal cell derived interferon-induced 2',5'-oligoadenylate synthetase (2-5 aase)/ribonuclease l (rnase l) system into various plants may make plants resistant to various pathogenic viruses and viroids. we have demonstrated th ... | 2002 | 12449532 |
| a natural recessive resistance gene against potato virus y in pepper corresponds to the eukaryotic initiation factor 4e (eif4e). | we show here that the pvr2 locus in pepper, conferring recessive resistance against strains of potato virus y (pvy), corresponds to a eukaryotic initiation factor 4e (eif4e) gene. rflp analysis on the pvy-susceptible and resistant pepper cultivars, using an eif4e cdna from tobacco as probe, revealed perfect map co-segregation between a polymorphism in the eif4e gene and the pvr2 alleles, pvr2(1) (resistant to pvy-0) and pvr2(2) (resistant to pvy-0 and 1). the cloned pepper eif4e cdna encoded a 2 ... | 2002 | 12492847 |
| negative-strand tospoviruses and tenuiviruses carry a gene for a suppressor of gene silencing at analogous genomic positions. | posttranscriptional silencing of a green fluorescent protein (gfp) transgene in nicotiana benthamiana plants was suppressed when these plants were infected with tomato spotted wilt virus (tswv), a plant-infecting member of the bunyaviridae: infection with tswv resulted in complete reactivation of gfp expression, similar to the case for potato virus y, but distinct from that for cucumber mosaic virus, two viruses known to carry genes encoding silencing suppressor proteins. agrobacterium-based lea ... | 2003 | 12502849 |
| the complete nucleotide sequence of pepper mottle virus-florida rna. | the pepper mottle virus-florida (pepmov-fl) rna genome was cloned and sequenced, and shown to consist of 9,717 nucleotides (nt) excluding the poly (a) tail. a single open reading frame was identified beginning at nucleotide position 169 encoding a polyprotein of 3068 amino acids. phylogenetic sequence analysis revealed that of 44 full-length viral rna genomes analyzed within the family potyviridae, pepmov-fl was most closely related to pepmov-california (pepmov-ca), potato virus y-h (pvy-h), pvy ... | 2003 | 12536304 |
| assessment of screening methods for the identification of genetically modified potatoes in raw materials and finished products. | qualitative polymerase chain reaction methods for the detection of genetically modified potatoes have been investigated that can be used for screening purposes and identification of insect-resistant and virus-resistant potatoes in food. the presence of the nos terminator from agrobacterium tumefaciens and the antibiotic marker gene nptii (neomycin-phosphotransferase ii) was demonstrated in three commercialized bt-potato lines (monsanto co., st. louis, mo, usa) and one noncommercial gm-potato pro ... | 2003 | 12537422 |
| genomic sequence of wild potato mosaic virus as compared to the genomes of other potyviruses. | the complete nucleotide sequence of wild potato mosaic virus (wpmv) was determined, showing that it is a distinct member of the genus potyvirus (family potyviridae). the genome consists of 9853 nucleotides and encodes a single polyprotein of 3065 amino acids. the 5'- and 3'-non translated regions (ntr) were 182 and 472 nucleotides, respectively. alignment of the predicted wpmv polyprotein sequence with other members of the genus potyvirus revealed nine putative cleavage sites resulting in ten ma ... | 2003 | 12556999 |
| potato gene y-1 is an n gene homolog that confers cell death upon infection with potato virus y. | adg2 is a dna sequence mapped to a resistance (r) gene-rich region at the distal end of chromosome xi in potato (solanum tuberosum subsp. andigena). the gene, in which adg2 represents the predicted nucleotide-binding domain (nbs), was cloned and characterized. the coding region of the gene (designated as y-1) is 6,187 bp long and structurally similar to gene n that confers hypersensitive resistance to tobacco mosaic virus in nicotiana spp. both belong to the tir-nbs-lrr class of genes and show 5 ... | 2002 | 12118888 |
| aphid transmission of potato virus y inhibited by oils. | | 1962 | 14014835 |
| evidence for expression level-dependent modulation of carbohydrate status and viral resistance by the potato leafroll virus movement protein in transgenic tobacco plants. | high-level constitutive expression of the cell-to-cell movement protein from the phloem-restricted potato leafroll virus (plrv-mp17) in transgenic tobacco plants leads to growth retardation and severe phenotypic changes of source leaves paralleled by a drastic accumulation of soluble sugars and starch (herbers et al., 1997). to investigate whether the mp17-induced alteration in carbon metabolism is related to the targeting and modification of specific plasmodesmata (pd) or is rather due to pleio ... | 2001 | 11849593 |
| a new approach for the simultaneous differentiation of biological and geographical strains of potato virus y by uniplex and multiplex rt-pcr. | two strains of potato virus y (pvy), the common (pvy(o)) and the tobacco veinal necrosis (pvy(n)) have been known for decades. more recently, a tuber ringspot necrosis (pvy(ntn)), and several recombinants of pvy(o) and pvy(n) (designated here as pvy(n:o)) have been described. further, the pvy(n) group of strains have been assigned to two geographical subgroups of european (eu) pvy(n/ntn) and the north american (na) pvy(n/ntn). the evolution of new pvy(n) strains, has complicated the diagnosis, w ... | 2002 | 12020791 |
| transgenic tobacco plants expressing the potato virus x open reading frame 3 gene develop specific resistance and necrotic ring symptoms after infection with the homologous virus. | tobacco plants were transformed with the open reading frame 3 gene from potato virus x (pvx) coding for the p12 protein. although the transgenic plants exhibited a normal morphological aspect, microscopic examination revealed extensive alterations in leaf tissue structure. after being challenged with pvx, the transgenic plants showed resistance to pvx infection and formation of specific leaf symptoms consisting of concentric rings encircled by necrotic borders. these novel symptoms were accompan ... | 2001 | 11763125 |