| host-controlled cell-to-cell movement of a hybrid barley stripe mosaic virus expressing a dianthovirus movement protein. | the triple gene block (tgb) of barley stripe mosaic virus (bsmv), coding for viral movement proteins (mps), was replaced by the single mp gene of red clover necrotic mosaic virus (rcnmv). accumulation of the hybrid virus in barley plants (the selective host for bsmv) was reduced compared to bsmv. the hybrid virus induced small necrotic local lesions on chenopodium amaranticolor leaves and did not infect nicotiana clevelandii (the selective host for rcnmv). the hybrid virus accumulated in the ino ... | 1997 | 9268764 |
| polygalacturonase-inhibiting proteins (pgips) with different specificities are expressed in phaseolus vulgaris. | the pgip-1 gene of phaseolus vulgaris, encoding a polygalacturonase-inhibiting protein (pgip), pgip-1 (p. toubart, a. desiderio, g. salvi, f. cervone, l. daroda, g. de lorenzo, c. bergmann, a. g. darvill, and p. albersheim, plant j. 2:367-373, 1992), was expressed under control of the cauliflower mosaic virus 35s promoter in tomato plants via agrobacterium tumefaciens-mediated transformation. transgenic tomato plants with different expression levels of pgip-1 were used in infection experiments w ... | 1997 | 9304859 |
| the enigma of px: a host-dependent cis-acting element with variable effects on tombusvirus rna accumulation. | tomato bushy stunt virus (tbsv) is a small isometric virus that contains a single-stranded rna genome with five major genes. in this study, we have analyzed the importance of an additional small sixth open reading frame (orf) of 207 nucleotides, designated px, which resides at the 3' end of the genome. bioassays showed that deletions or additions of nucleotides at the 5' end of the px gene that were designed to disrupt the orf, or site-specific inactivation of its start codon, all gave rise to t ... | 1997 | 9344907 |
| characterization of cucumber mosaic virus. iv. movement protein and coat protein are both essential for cell-to-cell movement of cucumber mosaic virus. | cdna clones of cucumber mosaic virus (cmv) rna 3 were modified to express the jellyfish green fluorescent protein (gfp) in place of the 3a movement protein (mp) or coat protein (cp), as fusions to the n (gfp-3a) or c (3a-gfp) terminus of the mp or from a separate open reading frame as part of tricistronic rnas 3. cmv rna transcripts containing the individual modified rnas 3 were unable to infect either nicotiana tabacum or nicotiana benthamiana systemically. infection, as measured by confocal mi ... | 1997 | 9356336 |
| new ribosome-inactivating proteins with polynucleotide:adenosine glycosidase and antiviral activities from basella rubra l. and bougainvillea spectabilis willd. | new single-chain (type 1) ribosome-inactivating proteins (rips) were isolated from the seeds of basella rubra l. (two proteins) and from the leaves of bougainvillea spectabilis willd. (one protein). these rips inhibit protein synthesis both in a cell-free system, with an ic50 (concentration causing 50% inhibition) in the 10(-10) m range, and by various cell lines, with ic50s in the 10(-8)-10(-6) m range. all three rips released adenine not only from rat liver ribosomes but also from escherichia ... | 1997 | 9421927 |
| molecular characterization of tobacco squalene synthase and regulation in response to fungal elicitor. | the enzyme squalene synthase (ss) represents the first commitment of carbon from the general isoprenoid pathway toward sterol biosynthesis and is a potential point for regulation of sterol biosynthesis. the isolation and characterization of tobacco (nicotiana tabacum) squalene synthase (tss) cdna and genomic dna clones, as well as determination of the steady state level of tss mrna in response to elicitor treatment, were investigated. cdna clones for tss were isolated from poly (a)+ rna using a ... | 1998 | 9448707 |
| charge changes near the n terminus of the coat protein of two potyviruses affect virus movement. | mutants of tobacco vein mottling virus (tvmv) with substitutions of lys or arg for asp in the dag motif at position 5 in the coat protein (cp) failed to infect tobacco plants systemically, but replicated and produced virions in protoplasts. occasional systemic infections occurred when nicotiana benthamiana or transgenic tobacco plants expressing wild-type tvmv cp were inoculated with these mutants, but viral progeny contained reversions to negatively or non-charged amino acids at position 5 or s ... | 1998 | 9460938 |
| plum pox potyvirus resistance associated to transgene silencing that can be stabilized after different number of plant generations. | nicotiana benthamiana plants were transformed with a fragment of the plum pox potyvirus (ppv) genome that encodes the nuclear inclusion a (nia) and b (nib) proteins and the n-terminus of the capsid protein (nia-nib-cp). lines transformed with this ppv genomic fragment harboring mutations in the gdd replicase-motif were also obtained. plants of niadeltav lines that carry a gdd to vdd mutation in the ppv transgene, were immune to ppv infection. the resistance was highly specific, since it was only ... | 1998 | 9469941 |
| a dna clone encoding the full-length infectious genome of odontoglossum ringspot tobamovirus and mutagenesis of its coat protein gene. | a full-length dna clone encoding the genome of odontoglossum ringspot tobamovirus (orsv) was synthesized and placed adjacent to a bacteriophage t7 rna polymerase promoter. capped-rna transcripts produced in vitro were highly infectious when mechanically inoculated onto seedlings of nicotiana benthamiana and oncidium gower ramsey. a representative clone, designated pot2, caused a disease phenotype identical to that produced by parental viral rna. elisa, western blot analysis, northern blot hybrid ... | 1998 | 9505974 |
| intracellular location of two groundnut rosette umbravirus proteins delivered by pvx and tmv vectors. | the proteins encoded by open reading frames (orf) 3 and 4 of groundnut rosette umbravirus (grv) were expressed in nicotiana benthamiana as fusions with green fluorescent protein (gfp) from modified potato virus x (pvx) and tobacco mosaic virus (tmv) vectors. regardless of which plant virus vector was used, gfp fused to the orf3 protein accumulated in large cytoplasmic inclusion bodies and in nucleoli, whereas gfp fused to the orf4 protein was found in cell walls close to plasmodesmata. cell-to-c ... | 1998 | 9514976 |
| the use of dig-labelled crna probes for the detection of cymbidium mosaic potexvirus (cymmv) and odontoglossum ringspot tobamovirus (orsv) in orchids. | dig-labelled sense and antisense crna probes were synthesized from cdna clones of cymmv and orsv for virus detection in infected plants. a slot-blot hybridization assay was developed using either crude leaf extracts or total rna from infected leaves. the assay could detect 50 and 250 pg of purified cymmv and orsv rna, respectively. as little as 30 mg of nicotiana benthamiana infected leaves was sufficient to provide positive detection. cymmv and orsv were detected at 3125 and 625 times dilution ... | 1998 | 9562413 |
| specific sequence changes in the 5'-terminal region of the genome of satellite tobacco mosaic virus are required for adaptation to tobacco mosaic virus. | the genome of satellite tobacco mosaic virus (stmv) adapted to tobacco mosaic virus (tmv), tomato mosaic virus or green tomato atypical mosaic virus consistently had two single base deletions at positions 1 and 61, corresponding to bases a and g, respectively, as compared to the type-strain genome which is naturally adapted to tobacco mild green mosaic virus (tmgmv). transcript rnas (stmv(tmv)) from clone pstmv(tmv) which captured the deletions at positions 1 and 61 were infectious when co-inocu ... | 1998 | 9568987 |
| the movement protein and coat protein of alfalfa mosaic virus accumulate in structurally modified plasmodesmata. | in systemically infected tissues of nicotiana benthamiana, alfalfa mosaic virus (amv) coat protein (cp) and movement protein (mp) are detected in plasmodesmata in a layer of three to four cells at the progressing front of infection. besides the presence of these viral proteins, the plasmodesmata are structurally modified in that the desmotubule is absent and the diameter has increased drastically (almost twofold) when compared to plasmodesmata in uninfected cells or cells in which amv infection ... | 1998 | 9601503 |
| recombination between viral dna and the transgenic coat protein gene of african cassava mosaic geminivirus. | nicotiana benthamiana was transformed with three different constructs (pcra1, pcra2 and pjc1) containing the coat protein coding sequence of african cassava mosaic virus (acmv). transformed plants were inoculated with a coat protein deletion mutant of acmv that induces mild systemic symptoms in control plants. several inoculated plants of transgenic lines cra1/3, cra1/4, cra2/1 and cra2/2 developed severe systemic symptoms typical of acmv. dna analysis revealed that, in these plants, recombinati ... | 1998 | 9603342 |
| susceptibility of peach gf 305 seedlings and selected herbaceous plants to plum pox virus isolates from western slovakia. | the susceptibility of peach gf 305 seedlings and herbaceous plants to five plum pox virus (ppv) isolates from orchards of western slovakia was investigated. ppv was isolated from diseased plum, apricot and peach trees, and transmitted by chip-budding to peach gf 305. the herbaceous plants were infected by mechanical inoculation. the transmission was analysed by symptomatology and double sandwich enzyme-linked immunosorbent assay (das-elisa). infected peaches developed leaf distortion, tissue cle ... | 1997 | 9607094 |
| mutations in viral movement protein alter systemic infection and identify an intercellular barrier to entry into the phloem long-distance transport system. | viral systemic infection of a plant host involves two processes, cell-to-cell movement and long-distance transport. molecular determinants associated with these two processes were probed by investigating the effects that alanine scanning mutations in the movement protein (mp) of red clover necrotic mosaic virus (rcnmv) had on viral infection in the plant hosts nicotiana edwardsonii, vigna unguiculata (cowpea), and the experimental plant nicotiana benthamiana. plants were inoculated with rcnmv ex ... | 1998 | 9614869 |
| nicotiana benthamiana plants transformed with the plum pox virus helicase gene are resistant to virus infection. | nicotiana benthamiana domin. plants were transformed with the cytoplasmic inclusion protein (ci) gene of plum pox potyvirus (ppv) to investigate, whether this non-structural protein would be able to confer resistance. the ci protein is an rna helicase, which contains a conserved nucleotide binding motif (ntbm) and plays an important role in viral replication. two gene constructions were developed for plant transformation. the first contains the original coding sequence of the ci gene under the c ... | 1998 | 9617773 |
| use of modified plum pox virus coat protein genes developed to limit heteroencapsidation-associated risks in transgenic plants. | aphid transmission of a non-aphid-transmissible strain of zucchini yellow mosaic virus (zymv-nat) occurs in transgenic plants expressing the plum pox potyvirus (ppv) coat protein (cp) gene. heteroencapsidation has been shown to be responsible for this modification in the epidemiological characteristics of the infecting virus. in order to prevent this biological risk, several modified ppv cp constructs were produced that were designed to interfere with heteroencapsidation itself or to block aphid ... | 1998 | 9634095 |
| initiation and maintenance of virus-induced gene silencing | the phytoene desaturase (pds) gene of nicotiana benthamiana was silenced in plants infected with potato virus x (pvx) vectors carrying pds inserts, and a green fluorescent protein (gfp) transgene was silenced in plants infected with pvx-gfp. this virus-induced gene silencing (vigs) is post-transcriptional and cytoplasmic because it is targeted against exons rather than introns of pds rna and against viral rnas. although pds and gfp rnas are most likely targeted through the same mechanism, the vi ... | 1998 | 9634582 |
| characterization of cucumber mosaic virus. v. cell-to-cell movement requires capsid protein but not virions. | to ascertain the importance of amino-terminal proximal capsid protein (cp) sequences in cel-to-cell movement, virion formation, and stabilization, two cp mutants of cucumber mosaic virus (cmv) were generated by deletion of sequences encoding cp amino acids 15-40 (delta sal-nru) or 26-40 (delta sac-nru). wildtype cmv and cmv containing delta sac-nru could infect systemically four host species, although symptoms induced by the two viruses usually were different cmv containing delta sal-nru could o ... | 1998 | 9657941 |
| changing patterns of localization of the tobacco mosaic virus movement protein and replicase to the endoplasmic reticulum and microtubules during infection. | tobacco mosaic virus (tmv) derivatives that encode movement protein (mp) as a fusion to the green fluorescent protein (mp:gfp) were used in combination with antibody staining to identify host cell components to which mp and replicase accumulate in cells of infected nicotiana benthamiana leaves and in infected by-2 protoplasts. mp:gfp and replicase colocalized to the endoplasmic reticulum (er; especially the cortical er) and were present in large, irregularly shaped, er-derived structures that ma ... | 1998 | 9668131 |
| nicotiana benthamiana plants expressing beet necrotic yellow vein virus (bnyvv) coat protein-specific scfv are partially protected against the establishment of the virus in the early stages of infection and its pathogenic effects in the late stages of infection. | transgenic plants of nicotiana benthamiana expressing single chain antibody fragments (scfv) specific for the coat protein of beet necrotic yellow vein virus (bnyvv) and non-expressing control plants were inoculated with bnyvv mechanically and by means of the vector polymyxa betae. the scfv were presumably expressed in the endoplasmic reticulum (er). the average time needed for infections to become detectable was longer in the scfv-expressing plants than in the non-expressing control plants. in ... | 1997 | 9672643 |
| coat protein interactions involved in tobacco mosaic tobamovirus cross-protection. | to investigate the molecular role of the tobacco mosaic tobamovirus (tmv) coat protein (cp) in conferring cross-protection, a potato x potexvirus (pvx) vector (s. chapman, plant j. 2, 549-557, 1992) was used to systemically express a set of tmv mutant cps in nicotiana benthamiana prior to challenge inoculation with tmv. pvx-expressed wild-type tmv cp delayed tmv accumulation for up to 2 weeks compared to unprotected plants or plants preinfected with the unmodified pvx vector. similar delays in t ... | 1998 | 9721228 |
| identification of genes involved in replication and movement of peanut clump virus. | the genome of peanut clump pecluvirus (pcv) consists of two messenger rna components which contain, respectively, three and five open reading frames (orfs). inoculation of transcripts from full-length cdna clones derived from the pcv rnas showed that rna-1 is able to replicate in the absence of rna-2 in protoplasts, but both rnas are necessary for plant infection. to investigate the role of different gene products in viral rna replication and movement, transcripts from mutant cdna clones were in ... | 1998 | 9721240 |
| deletions in the conserved amino-terminal basic arm of cucumber mosaic virus coat protein disrupt virion assembly but do not abolish infectivity and cell-to-cell movement. | the n-terminal basic arm of cucumber mosaic cucumovirus (cmv) coat protein (cp) contains a conserved arginine-rich motif, which is characteristic of rna binding proteins of several plant and nonplant viruses. to identify regions of the cmv cp n-terminus that are essential for interacting with viral genomic rna, a comprehensive set of mutations was engineered into biologically active clones of cmv rna3 and the behavior of each variant with respect to infectivity, packaging and movement was examin ... | 1998 | 9721241 |
| evolution of a quadripartite hybrid virus by interspecific exchange and recombination between replicase components of two related tripartite rna viruses. | cucumber mosaic virus (cmv) and tomato aspermy virus (tav) belong to the cucumovirus genus. they have a tripartite genome consisting of single-stranded rnas, designated 1, 2, and 3. previous studies have shown that viable pseudorecombinants could be created in vitro by reciprocal exchanges between cmv and tav rna 3, but exchanges of rnas 1 and 2 were replication deficient. when we coinoculated cmv rnas 2 and 3 along with tav rnas 1 and 2 onto nicotiana benthamiana, a hybrid quadripartite virus a ... | 1998 | 9724730 |
| tobacco mosaic virus infection induces severe morphological changes of the endoplasmic reticulum. | the tobacco mosaic virus (tmv) movement protein (mp) facilitates transport of virus infection between adjacent cells by modifying plasmodesmata. previous studies suggested that the cytoskeleton and the endomembrane system are involved in this transport. we examined the effects of tmv infection on the endoplasmic reticulum (er) in transgenic nicotiana benthamiana that accumulate the green fluorescent protein (gfp) in the er. fluorescence microscopy was used to show that early in infection the er ... | 1998 | 9736708 |
| mutational analysis of bean yellow dwarf virus, a geminivirus of the genus mastrevirus that is adapted to dicotyledonous plants. | bean yellow dwarf virus (beydv) is an atypical member of the geminivirus genus mastrevirus that infects dicotyledonous plants. beydv dna contains six open reading frames (orfs) with the capacity to encode proteins in excess of 10 kda. two virion-sense orfs (v1 and v2) and two complementary-sense orfs (c1 and c2) have homologues in all mastreviruses, while orfs c3 and c4 are not conserved. to investigate their functions, each of the orfs has been truncated by either frame-shifting or the introduc ... | 1998 | 9747737 |
| strain variability of plum pox virus isolates from western slovakia. | leaf tissues of stone fruit trees (plum, apricot, peach and myrobalan) carrying symptoms of plum pox virus (ppv) infection and of peach gf 305 seedlings and nicotiana benthamiana infected experimentally with ppv were assayed for ppv by polymerase chain reaction (pcr). the expected 243 bp pcr products were subjected to restriction fragment length polymorphism (rflp) analysis with restriction endonucleases alui and rsai. all of the pcr products contained the alui site. the rsai restriction profile ... | 1998 | 9770072 |
| havana tomato virus, a new bipartite geminivirus infecting tomatoes in cuba. | the cloning and nucleotide sequence of a new bipartite geminivirus found in cuba is described. dna a (2620 nt) and dna b (2586 nt) presented a genomic structure resembling that of other geminiviruses transmitted by bemisia tabaci. both components had a common region of 168 nt with a 95% identity. typical elements involved in replication and transcription were found in this region, though group-characteristic arrangement of iterons was not conserved in this virus. sequence was compared with gemin ... | 1998 | 9787659 |
| asymmetric infectivity of pseudorecombinants of cabbage leaf curl virus and squash leaf curl virus: implications for bipartite geminivirus evolution and movement. | the bipartite geminiviruses squash leaf curl virus (sqlcv) and cabbage leaf curl virus (clcv) have distinct host ranges. sqlcv infects a broad range of plants within the cucurbitaceae, including pumpkin and squash, and clcv has a broad host range within brassicaceae that includes cabbage and arabidopsis thaliana. despite this, the genomic a components of these viruses share a high degree of sequence identity, particularly in the gene encoding the replication protein al1, and their common regions ... | 1998 | 9792839 |
| amino acids in the capsid protein of tomato yellow leaf curl virus that are crucial for systemic infection, particle formation, and insect transmission. | a functional capsid protein (cp) is essential for host plant infection and insect transmission in monopartite geminiviruses. we studied two defective genomic dnas of tomato yellow leaf curl virus (tylcv), sic and sicrcv. sic, cloned from a field-infected tomato, was not infectious, whereas sicrcv, which spontaneously originated from sic, was infectious but not whitefly transmissible. a single amino acid change in the cp was found to be responsible for restoring infectivity. when the amino acid s ... | 1998 | 9811744 |
| 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 |
| genetic determinants of host-specificity in bipartite geminivirus dna a components. | geminiviruses are small, ssdna-containing plant viruses. bean golden mosaic virus (bgmv) and tomato golden mosaic virus (tgmv) have bipartite genomes, the components of which are designated a and b. although they are closely related, bgmv and tgmv nevertheless exhibit distinct host-specific phenotypes, with bgmv being well adapted to beans and tgmv being well adapted to nicotiana benthamiana. a previous study showed that the two open reading frames (orfs) of dna b only partially determine the ho ... | 1998 | 9837800 |
| molecular studies on bromovirus capsid protein. | brome mosaic bromovirus (bmv) and cucumber mosaic cucumovirus (cmv) are structurally and genetically very similar. the specificity of the bmv and cmv coat proteins (cps) during in vivo encapsidation was studied using two rna3 chimera in which the respective cp genes were exchanged. the replicative competence of each chimera was analyzed in nicotiana benthamiana protoplasts, and their ability to cause infections was examined in two common permissive hosts, chenopodium quinoa and n. benthamiana. e ... | 1998 | 9837807 |
| expression and assembly of a full-length monoclonal antibody in plants using a plant virus vector. | we have used a tobacco mosaic virus-based vector to express monoclonal antibody (mab) co17-1a, directed to a colon cancer antigen, in plants. genes encoding heavy and light chains of this antibody were introduced independently into the tobacco mosaic virus vector. upon co-infection of nicotiana benthamiana plants with both recombinant virus constructs, genes for heavy and light chains were expressed and assembled into a full-length antibody. a functional plant-expressed antibody was detected by ... | 1998 | 9839927 |
| psa causes oncogenic suppression of agrobacterium by inhibiting vire2 protein export. | when coresident with the ti (tumor-inducing) plasmid, the 21-kda product of the osa gene of the plasmid psa can suppress crown gall tumorigenesis incited by agrobacterium tumefaciens. neither t-dna processing nor vir (virulence) gene induction is affected by the presence of osa in the bacterium. we used arabidopsis thaliana root segments and tobacco leaf discs to demonstrate that osa inhibits a. tumefaciens from transforming these plants to the stable phenotypes of tumorigenesis, kanamycin resis ... | 1999 | 9864329 |
| expression of an anther-specific chalcone synthase-like gene is correlated with uninucleate microspore development in nicotiana sylvestris. | two cdna clones, specifically expressed in nicotiana sylvestris anthers during uninucleate microspore development, were isolated using a subtractive hybridization approach. sequence analysis showed that one of them, nschslk, displayed a high level of similarity to several anther-specific chalcone synthase-like (chslk) proteins and an orf from chromosome i of arabidopsis thaliana. a lower, but significant, similarity to chalcone synthases and closely related enzymes (chsre) was also detected. the ... | 1998 | 9869422 |
| membrane targeting sequences in tombusvirus infections. | infection of nicotiana benthamiana cells with cymbidium ringspot (cymrsv) and carnation italian ringspot (cirv) viruses results in the formation of conspicuous membranous bodies [multivesicular bodies (mvbs)], which develop from modified peroxisomes or mitochondria, respectively. the organelle targeting signal is located in the proteins of 33 kda (cymrsv) or 36 kda (cirv) encoded by orf 1, which contain an n-terminal hydrophilic portion followed by two predicted hydrophobic transmembrane segment ... | 1998 | 9878622 |
| evolution of bamboo mosaic virus in a nonsystemic host results in mutations in the helicase-like domain that cause reduced rna accumulation. | a mutant population of bamboo mosaic potexvirus (bamv) was isolated after serial passage using chenopodium quinoa plants. while the wild type inoculum induced indistinct chlorotic lesions, the mutant produced obvious lesions on c. quinoa although rna accumulation of the mutant in nicotiana benthamiana protoplasts was significantly reduced compared to wild type. mutations were identified in the helicase-like domain. one rt-pcr-generated cdna clone (designated pl1-33) representing the helicase-lik ... | 1998 | 9879769 |
| a phage single-stranded dna (ssdna) binding protein complements ssdna accumulation of a geminivirus and interferes with viral movement. | geminiviruses are plant viruses with circular single-stranded dna (ssdna) genomes encapsidated in double icosahedral particles. tomato leaf curl geminivirus (tolcv) requires coat protein (cp) for the accumulation of ssdna in protoplasts and in plants but not for systemic infection and symptom development in plants. in the absence of cp, infected protoplasts accumulate reduced levels of ssdna and increased amounts of double-stranded dna (dsdna), compared to accumulation in the presence of wild-ty ... | 1999 | 9882367 |
| rapid production of specific vaccines for lymphoma by expression of the tumor-derived single-chain fv epitopes in tobacco plants. | rapid production of protein-based tumor-specific vaccines for the treatment of malignancies is possible with the plant-based transient expression system described here. we created a modified tobamoviral vector that encodes the idiotype-specific single-chain fv fragment (scfv) of the immunoglobulin from the 38c13 mouse b cell lymphoma. infected nicotiana benthamiana plants contain high levels of secreted scfv protein in the extracellular compartment. this material reacts with an anti-idiotype ant ... | 1999 | 9892697 |
| movement of hordeivirus hybrids with exchanges in the triple gene block. | the barley stripe mosaic virus (bsmv) triple gene block (tgb) coding for movement proteins (mps) was replaced with the respective tgb genes from two other hordeiviruses, poa semilatent virus (pslv) or lychnis ringspot virus (lrsv). the bsmv/lrsv recombinant did not exhibit infectivity on the plants tested, whereas the infection rate and host range of the bsmv/pslv hybrid were similar to those of bsmv. in particular, the bsmv/pslv hybrid infected nicotiana benthamiana, a nonhost plant for pslv, i ... | 1999 | 9918886 |
| mitotic stability of infection-induced resistance to plum pox potyvirus associated with transgene silencing and dna methylation. | plum pox potyvirus (ppv) infection of transgenic nicotiana benthamiana plants that expressed the ppv nib rna replicase carrying a gly to val mutation at the gdd motif (nibv lines) induced a phenotype of virus resistance and transgene silencing, which was not transmissible to the progeny after self-fertilization (h. s. guo and j. a. garcía, mol. plant-microbe interact. 10:160-170, 1997). here, we demonstrate that the induced resistance of nibv plants is mitotically stable after plant propagation ... | 1999 | 9926412 |
| restoration of wild-type virus by double recombination of tombusvirus mutants with a host transgene. | nicotiana benthamiana plants transformed with the coat protein gene of tomato bushy stunt virus (tbsv) failed to elicit effective virus resistance when inoculated with wildtype virus. subsequently, r1 and r2 progeny from 13 transgenic lines were inoculated with a tbsv mutant containing a defective coat protein gene. mild symptoms typical of those elicited in nontransformed plants infected with the tbsv mutant initially appeared. however, within 2 to 4 weeks, up to 20% of the transgenic plants sp ... | 1999 | 9926415 |
| construction of full-length cdna clones of lettuce mosaic virus (lmv) and the effects of intron-insertion on their viability in escherichia coli and on their infectivity to plants. | a full length cdna copy of the genomic rna of lettuce mosaic virus (lmv) was constructed under the control of an enhanced camv 35s promoter and of the nos terminator. this construct was found infectious when inoculated to lettuce plants. the intron ii of the bean nitrite reductase gene was engineered into the lmv fl cdna in order to relieve possible deleterious effects of viral sequences to escherichia coli cells and to evaluate the effects of the presence of the intron on the fl cdna infectivit ... | 1998 | 9930200 |
| expression of alfalfa mosaic virus coat protein in tobacco mosaic virus (tmv) deficient in the production of its native coat protein supports long-distance movement of a chimeric tmv. | alfalfa mosaic virus (almv) coat protein is involved in systemic infection of host plants, and a specific mutation in this gene prevents the virus from moving into the upper uninoculated leaves. the coat protein also is required for different viral functions during early and late infection. to study the role of the coat protein in long-distance movement of almv independent of other vital functions during virus infection, we cloned the gene encoding the coat protein of almv into a tobacco mosaic ... | 1999 | 10051680 |
| high resistance and control of biological risks in transgenic plants expressing modified plum pox virus coat protein. | transgenic plums transformed with the plum pox virus coat protein (ppv cp) gene displayed a resistance to the sharka disease (ravelonandro et al., 1997). however, the expression of ppv cp in transgenic plants may lead to complementation of deficient characteristic of an incoming potyvirus. indeed, an aphid-intransmissible strain of zucchini yellow mosaic virus (zymv-nat) could be transmitted when encapsidated by the engineered ppv cp (lecoq et al., 1993). to control such a risk, new ppv cp const ... | 1998 | 10073226 |
| sufficient length of a poly(a) tail for the formation of a potential pseudoknot is required for efficient replication of bamboo mosaic potexvirus rna. | rnas transcribed from a full-length infectious cdna clone of the bamboo mosaic potexvirus (strain o) genome, pbamv-o, were infectious to nicotiana benthamiana plants. mutant genomes in which the poly(a) tail is absent or replaced by a 3' trna-like structure from turnip yellow mosaic virus rna failed to amplify detectably in n. benthamiana protoplasts. no amplification was detected in protoplasts inoculated with transcripts containing 4, 7, or 10 adenylate residues at the 3' end, whereas transcri ... | 1999 | 10074116 |
| the 5' noncoding region of grapevine chrome mosaic nepovirus rna-2 triggers a necrotic response on three nicotiana spp. | the 5' noncoding region (ncr) of grapevine chrome mosaic nepovirus (gcmv) was cloned in a viral vector derived from potato virus x (pvx). the recombinant virus obtained was inoculated to nicotiana benthamiana, n. clevelandii, and n. tabacum plants. infected plants developed necrotic symptoms in place of the vein clearing and mosaic typically observed after inoculation with pvx. northern (rna) blot analysis showed that the replication of pvx was not specifically altered by the presence of the gcm ... | 1999 | 10188272 |
| bean yellow dwarf virus repa, but not rep, binds to maize retinoblastoma protein, and the virus tolerates mutations in the consensus binding motif. | it has previously been reported that complementary-sense gene products of wheat dwarf virus (wdv), a geminivirus of the genus mastrevirus that infects monocotyledonous plants, bind to human and maize retinoblastoma (rb) protein. rb proteins control cell-cycle progression by sequestering transcription factors required for entry into s-phase, suggesting that the virus modifies the cellular environment to produce conditions suitable for viral dna replication. using a yeast two-hybrid assay, we have ... | 1999 | 10191192 |
| the specificity of polygalacturonase-inhibiting protein (pgip): a single amino acid substitution in the solvent-exposed beta-strand/beta-turn region of the leucine-rich repeats (lrrs) confers a new recognition capability. | two members of the pgip gene family (pgip-1 and pgip-2) of phaseolus vulgaris l. were expressed separately in nicotiana benthamiana and the ligand specificity of their products was analysed by surface plasmon resonance (spr). polygalacturonase-inhibiting protein-1 (pgip-1) was unable to interact with pg from fusarium moniliforme and interacted with pg from aspergillus niger; pgip-2 interacted with both pgs. only eight amino acid variations distinguish the two proteins: five of them are confined ... | 1999 | 10228150 |
| functional expression in bacteria and plants of an scfv antibody fragment against tospoviruses. | recombinant antibodies expressed in plants ('plantibodies'), directed against crucial antigens and addressed to the right cell compartment, may be able to protect against viral diseases. moreover, antibody fragments produced in bacteria or plants may provide low cost reagents for immunodiagnosis. | 1999 | 10231089 |
| broad-spectrum protection against tombusviruses elicited by defective interfering rnas in transgenic plants. | we have designed a dna cassette to transcribe defective interfering (di) rnas of tomato bushy stunt virus (tbsv) and have investigated their potential to protect transgenic nicotiana benthamiana plants from tombusvirus infections. to produce rnas with authentic 5' and 3' termini identical to those of the native b10 di rna, the di rna sequences were flanked by ribozymes (rzdi). when rzdi rnas transcribed in vitro were mixed with parental tbsv transcripts and inoculated into protoplasts or plants, ... | 1999 | 10233970 |
| alfalfa mosaic virus rnas serve as cap donors for tomato spotted wilt virus transcription during coinfection of nicotiana benthamiana. | tomato spotted wilt virus (tswv) was shown to use alfalfa mosaic virus (amv) rnas as cap donors in vivo during a mixed infection in nicotiana benthamiana. by use of nested reverse transcription-pcr, tswv n and nss mrnas provided with capped leader sequences derived from all four amv rnas could be cloned and sequenced. the sequence specificity of the putative tswv endonuclease involved is discussed. | 1999 | 10233983 |
| strong host resistance targeted against a viral suppressor of the plant gene silencing defence mechanism. | the 2b protein encoded by cucumber mosaic cucumovirus (cmv2b) acts as an important virulence determinant by suppressing post-transcriptional gene silencing (ptgs), a natural plant defence mechanism against viruses. we report here that the tomato aspermy cucumovirus 2b protein (tav2b), when expressed from the unrelated tobacco mosaic tobamovirus (tmv) rna genome, activates strong host resistance responses to tmv in tobacco which are typical of the gene-for-gene disease resistance mechanism. domai ... | 1999 | 10329615 |
| subcellular localization and in vivo identification of the putative movement protein of olive latent virus 2. | the gene encoding the 36.5 kda ('36k') nonstructural protein located on rna3 of olive latent virus 2 (olv-2) was cloned, expressed with the escherichia coli pgex-2t system and the purified protein used to raise a polyclonal antiserum. immunoblot analysis of olv-2-infected nicotiana benthamiana plants showed that the 36k protein accumulated in the early stages of infection and was associated with a subcellular fraction enriched in cytoplasmic membranes. in infected cells there were tubular struct ... | 1999 | 10355755 |
| mutational analyses of the putative calcium binding site and hinge of the turnip crinkle virus coat protein. | the turnip crinkle carmovirus (tcv) coat protein (cp) is folded into r (rna-binding), s (shell), and p (protruding) domains. the s domain is an eight-stranded beta barrel common to the coat protein subunits of most rna viruses. a five-amino-acid hinge connects the s and p domains. in assembled particles, each pair of cp subunits is thought to bind a single calcium ion through interactions with three residues of one subunit and two residues of a neighboring subunit. these five residues comprise t ... | 1999 | 10364487 |
| a promoter from sugarcane bacilliform badnavirus drives transgene expression in banana and other monocot and dicot plants. | a 1369 bp dna fragment (sc) was isolated from a full-length clone of sugarcane bacilliform badnavirus (scbv) and was shown to have promoter activity in transient expression assays using monocot (banana, maize, millet and sorghum) and dicot plant species (tobacco, sunflower, canola and nicotiana benthamiana). this promoter was also tested for stable expression in transgenic banana and tobacco plants. these experiments showed that this promoter could drive high-level expression of the beta-glucuro ... | 1999 | 10380808 |
| phosphorylation and/or presence of serine 37 in the movement protein of tomato mosaic tobamovirus is essential for intracellular localization and stability in vivo. | the p30 movement protein (mp) of tomato mosaic tobamovirus (tomv) is synthesized in the early stages of infection and is phosphorylated in vivo. here, we determined that serine 37 and serine 238 in the tomv mp are sites of phosphorylation. mp mutants in which serine was replaced by alanine at positions 37 and 238 (lq37a238a) or at position 37 only (lq37a) were not phosphorylated, and mutant viruses did not infect tobacco or tomato plants. by contrast, mutation of serine 238 to alanine did not af ... | 1999 | 10400781 |
| the n-terminal 77 amino acids from tobacco n-acetylglucosaminyltransferase i are sufficient to retain a reporter protein in the golgi apparatus of nicotiana benthamiana cells. | in order to investigate sequences of tobacco n-acetylglucosaminyltransferase i (gnti), involved in targeting to and retention in the plant golgi apparatus the cytoplasmic transmembrane stem (cts) region of the enzyme was cloned in frame with the cdna of the green fluorescent protein (gfp) and subsequently transiently expressed in nicotiana benthamiana plants using a tobacco mosaic virus (tmv) based expression vector. confocal laser scanning microscopy showed small fluorescent vesicular bodies in ... | 1999 | 10403396 |
| a defective rna associated with bamboo mosaic virus and the possible common mechanisms for rna recombination in potexviruses. | a naturally occurring 1.1 kb rna was isolated from purified virions of bamboo mosaic potexvirus isolate s (bamv-s). this rna is a defective rna (d rna) derived from a single internal deletion of the bamv genome. a cdna clone representing the complete nucleotide sequence of the bamv-s d rna was generated and its nucleotide sequence was determined. the bamv d cdna is 1015 nts in length [excluding the poly(a) tail] and consists of two regions corresponding to 867 nts of the 5' terminus and 148 nts ... | 1999 | 10403698 |
| evidence for two nonoverlapping functional domains in the potato virus x 25k movement protein. | to study subdomain organization of the potato virus x (pvx) movement protein (mp) encoded by the first gene in the triple gene block (tgb), we mutated the 25-kda tgbp1 protein. the n-terminal deletion of the helicase motifs i, ia, and ii resulted in loss of the atpase activity and rna binding. a frameshift mutation truncating the c-terminal motifs v and vi gave rise to increase of the tgbp1 atpase activity and had little effect on rna binding in vitro. fusions of the green fluorescent protein wi ... | 1999 | 10405356 |
| subcellular localization of the hsp70-homolog encoded by beet yellows closterovirus. | closteroviridae is the only viral family coding for a homolog of hsp70 (hsp70h). polyclonal antiserum to recombinant beet yellows closterovirus (byv) hsp70h was generated and used for immunogold labeling of the leaf samples derived from the infected nicotiana benthamiana plants. ultrastructural analysis revealed the preferential accumulation of byv in phloem, although occasional infection of the leaf mesophyll cells was also observed. the strongest hsp70h-specific labeling was associated with vi ... | 1999 | 10405369 |
| restoration of a stem-loop structure required for potato virus x rna accumulation indicates selection for a mismatch and a gnra tetraloop. | the 5' region of potato virus x (pvx) rna contains a stem-loop structure, stem-loop 1 (sl1), that is required for efficient plus-strand rna accumulation. to determine how changes to individual elements in sl1 are accommodated by the virus, we inoculated pvx transcripts containing modifications in the terminal tetraloop (tl), stem c (sc), and stem d (sd) regions onto nicotiana benthamiana plants and analyzed progeny rnas over a series of passages. several progeny rnas isolated from plants inocula ... | 1999 | 10417268 |
| turnip mosaic potyvirus resistance in nicotiana benthamiana derived by post-transcriptional gene silencing. | the coat protein (cp) gene of turnip mosaic potyvirus isolate esc8 (tumv-esc8) was cloned and sequenced. comparisons of the 867-nucleotide (nt) cp region with those of 11 tumv isolates showed 86.7-89.3% nucleotide identity and 92.4-95.5% amino acid identity. the cp gene was cloned into a plant expression vector and transformed into nicotiana benthamiana plants via agrobacterium tumefaciens-mediated leaf disk transformation. progeny from r0 lines was screened for resistance to tumv-esc8. five of ... | 1999 | 10478490 |
| interactions between tombusviruses and satellite rnas of tomato bushy stunt virus: a defect in sat rna b1 replication maps to orf1 of a helper virus. | the biological properties of two recently described satellite rnas of tomato bushy stunt virus (tbsv) were analyzed in natural and experimental hosts. full-length cdna clones were constructed for sat rnas b1(822 nt) and b10 (612 nt) and used in inoculations with satellite-free transcripts of different tombusviruses. in all virus-host combinations tested, tbsv sat rna b10 drastically reduced the accumulation of viral genomic rna and attenuated symptoms. in contrast, sat rna b1 caused a less marke ... | 1999 | 10489347 |
| internal initiation of translation directed by the 5'-untranslated region of the tobamovirus subgenomic rna i(2). | previously we reported that, unlike rna of typical tobamoviruses, the translation of the coat protein (cp) gene of a crucifer-infecting tobamovirus (crtmv) in vitro occurred by an internal ribosome entry mechanism mediated by the 148-nt region that contained an internal ribosome entry site (ires(cp,148)(cr)). the equivalent 148-nt sequence from tmv u1 rna (u1(cp,148)(sp)) was incapable of promoting internal initiation. in the present work, we have found that the 228-nt region upstream of the mov ... | 1999 | 10544089 |
| protection of mice against challenge with foot and mouth disease virus (fmdv) by immunization with foliar extracts from plants infected with recombinant tobacco mosaic virus expressing the fmdv structural protein vp1. | a tobacco mosaic virus (tmv)-based vector has been used to express in plants the complete open reading frame coding for vp1, the major immunogenic protein of foot and mouth disease virus (fmdv). in vitro rna transcripts were inoculated into nicotiana benthamiana plants and detectable amounts of recombinant vp1 were identified by western blot as soon as 4 days postinfection. foliar extracts prepared from infected leaves were injected intraperitoneally into mice and all of the immunized animals de ... | 1999 | 10544132 |
| a nanovirus-like dna component associated with yellow vein disease of ageratum conyzoides: evidence for interfamilial recombination between plant dna viruses. | yellow vein disease of ageratum conyzoides, a weed species that is widely distributed throughout asia, has been attributed to infection by the geminivirus ageratum yellow vein virus (ayvv). in addition to a single ayvv genomic component (dna a), we have previously demonstrated that infected plants contain chimeric defective viral components, comprising dna a and nongeminiviral sequences, that act as defective interfering dnas. a database search has revealed that the nongeminiviral sequences of o ... | 1999 | 10544139 |
| the first triple gene block protein of peanut clump virus localizes to the plasmodesmata during virus infection. | the subcellular localization of the first triple gene block protein (tgbp1) of peanut clump pecluvirus (pcv) was studied by subcellular fractionation and immunogold cytochemistry using tgbp1-specific antibodies raised against a fusion protein expressed in and purified from bacteria. in the inoculated and apical leaves of virus-infected nicotiana benthamiana, tgbp1 localized to the cell wall and p30 fractions. electron microscopy of immunogold-decorated ultrathin sections of the infected leaf tis ... | 1999 | 10544148 |
| nonstructural proteins of tobacco rattle virus which have a role in nematode-transmission: expression pattern and interaction with viral coat protein. | rna 2 of tobacco rattle virus isolate ppk20 encodes the viral coat protein (cp) and two nonstructural proteins of 40 kda ('40k protein') and 32.8 kda ('32.8k'). the 40k protein is required for transmission of the virus by the vector nematode paratrichodorus pachydermus whereas the 32.8k protein may be involved in transmission by other vector nematode species. an antiserum was raised against the 40k protein expressed in e. coli and used to study the expression and subcellular localization of this ... | 1999 | 10567661 |
| suppression of gene silencing: a general strategy used by diverse dna and rna viruses of plants. | in transgenic and nontransgenic plants, viruses are both initiators and targets of a defense mechanism that is similar to posttranscriptional gene silencing (ptgs). recently, it was found that potyviruses and cucumoviruses encode pathogenicity determinants that suppress this defense mechanism. here, we test diverse virus types for the ability to suppress ptgs. nicotiana benthamiana exhibiting ptgs of a green fluorescent protein transgene were infected with a range of unrelated viruses and variou ... | 1999 | 10570213 |
| expression of the bs2 pepper gene confers resistance to bacterial spot disease in tomato. | the bs2 resistance gene of pepper specifically recognizes and confers resistance to strains of xanthomonas campestris pv. vesicatoria that contain the corresponding bacterial avirulence gene, avrbs2. the involvement of avrbs2 in pathogen fitness and its prevalence in many x. campestris pathovars suggests that the bs2 gene may be durable in the field and provide resistance when introduced into other plant species. employing a positional cloning strategy, the bs2 locus was isolated and the gene wa ... | 1999 | 10570214 |
| infectious rna transcripts from grapevine virus a cdna clone. | a full length cdna clone of grapevine virus a (gva) was constructed downstream from the bacteriophage t7 rna polymerase promoter. capped in vitro-transcribed rna was infectious in nicotiana benthamiana and n. clevelandii plants. symptoms induced by the rna transcripts or by the parental virus were indistinguishable. the infectivity of the in vitro-transcribed rna was confirmed by serological detection of the virus coat and movement proteins and by observation of virions by electron microscopy. t ... | 1999 | 10595415 |
| genetic dissection of tomato bushy stunt virus p19-protein-mediated host-dependent symptom induction and systemic invasion. | the plus-sense single-stranded rna of tomato bushy stunt virus (tbsv) encodes a 19-kda protein, which is translated from a 3' proximal open reading frame (p19) that is entirely nested within the cell-to-cell movement gene (p22). expression of the cytosolic p19-protein induces either a systemic lethal collapse in nicotiana benthamiana and n. clevelandii, or necrotic local lesions on resistant n. tabacum. in spinach, the p19-protein is required at high abundance for efficient systemic invasion. th ... | 2000 | 10612662 |
| virus-like particles assemble in plants and bacteria expressing the coat protein gene of indian peanut clump virus. | cdna copies of the coat protein (cp) gene of indian peanut clump virus (ipcv)-h were introduced into cells of nicotiana benthamiana or escherichia coli by transformation with vectors based on prokii or pet respectively. in both plant and bacterial cells, ipcv cp was expressed and assembled to form virus-like particles (vlp). in plant extracts, the smallest preponderant particle length was about 50 nm. other abundant lengths were about 85 and about 120 nm. the commonest vlp length in bacterial ex ... | 2000 | 10640566 |
| evidence of synergism between african cassava mosaic virus and a new double-recombinant geminivirus infecting cassava in cameroon. | stem cuttings were collected in cameroon from cassava plants displaying cassava mosaic disease (cmd) symptoms. the nature of the viruses present was determined by using the pcr with primers specific for the coat protein (cp) genes of african cassava mosaic virus (acmv) and east african cassava mosaic virus (eacmv). all samples were infected by acmv and eight of the 50 samples were infected by both acmv and an eacmv-like virus. the complete nucleotide sequences of dna-a and -b of representative a ... | 2000 | 10640569 |
| the role of abi1 in abscisic acid signal transduction: from gene to cell. | the semi-dominant abi1-1 mutation of arabidopsis interferes with multiple aspects of abscisic acid signal transduction resulting in reduced seed dormancy and sensitivity of root growth in aba. furthermore, the mutant transpires excessively as a result of abnormal stomatal regulation leading to a wilty phenotype. the abi1 gene has been cloned. the carboxyl-terminal domain of the predicted abi1 protein is related to the 2c class of serine-threonine phosphatases while no overt homology was found in ... | 1998 | 10645425 |
| potato mop-top virus rna can move long distance in the absence of coat protein: evidence from resistant, transgenic plants. | transgenic expression of a translatable version of the potato mop-top virus (pmtv) coat protein (cp) gene (encoded by rna 3) in nicotiana benthamiana prevented production of symptoms and infective virus particles. rnas 1 and 2 accumulated in inoculated and systemic leaves but, apart from small amounts of cp transgene rna transcript, no genomic-length rna 3 was found. crude leaf extracts from inoculated plants were not infective. however, when rna extracts from such transgenic plants were inocula ... | 2000 | 10656594 |
| replication of heterologous combinations of helper and defective rna of citrus tristeza virus. | citrus tristeza virus (ctv) populations are among the more complex of plant rna viruses with unusual mixtures of strains and defective rnas (drnas). citrus plants infected with different ctv isolates contain multiple drna molecules that differ in size and relative abundance within and between isolates. additionally, we found mixtures of heterologous drnas in populations. to examine the replication of ctv drnas, the protoplast system had to be extended to support helper-assisted amplification of ... | 2000 | 10662631 |
| 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 |
| tagging potato leafroll virus with the jellyfish green fluorescent protein gene. | a full-length cdna corresponding to the rna genome of potato leafroll virus (plrv) was modified by inserting cdna that encoded the jellyfish green fluorescent protein (gfp) into the p5 gene near its 3' end. nicotiana benthamiana protoplasts electroporated with plasmid dna containing this cdna behind the 35s rna promoter of cauliflower mosaic virus became infected with the recombinant virus (plrv-gfp). up to 5% of transfected protoplasts showed gfp-specific fluorescence. progeny virus particles w ... | 2000 | 10675399 |
| virus recovery is induced in brome mosaic virus p2 transgenic plants showing synchronous complementation and rna-2-specific silencing. | nicotiana benthamiana plants expressing brome mosaic virus (bmv) p2 protein complemented replication of rnas1 + 3 but, surprisingly, supported little or no replication of rna-2. despite this, the p2 transgenic plants were able to support systemic migration of rnas-1 and -3. kinetic analyses showed identical degradation rates for rnas-2 and -3, greatly detracting from the concept of an induction of an rna-2-specific degradation system. deletion analysis identified a 200-nucleotide sequence that m ... | 2000 | 10707350 |
| evolutionarily related sindbis-like plant viruses maintain different levels of population diversity in a common host. | the levels of population diversity of three related sindbis-like plant viruses, tobacco mosaic virus (tmv), cucumber mosaic virus (cmv), and cowpea chlorotic mottle virus (ccmv), in infections of a common host, nicotiana benthamiana, established from genetically identical viral rna were examined. despite probably having a common evolutionary ancestor, the three viruses maintained different levels of population diversity. cmv had the highest levels of diversity, tmv had an intermediate level of d ... | 2000 | 10708428 |
| rapid, high-level expression of glycosylated rice alpha-amylase in transfected plants by an rna viral vector. | tobamoviral vectors have been developed for the heterologous expression of glycoproteins in plants. the rice alpha-amylase gene (os103) was placed under the transcriptional control of a tobamovirus subgenomic promoter in a rna viral vector. one to two weeks after inoculation, transfected nicotiana benthamiana plants accumulated glycosylated alpha-amylase to levels of at least 5% total soluble protein. the 46kda recombinant enzyme was purified, and its structural and biological properties were an ... | 2000 | 10713457 |
| subcellular sorting of small membrane-associated triple gene block proteins: tgbp3-assisted targeting of tgbp2. | we studied subcellular distribution of green fluorescent protein (gfp)-tagged movement proteins encoded by the second and the third genes of poa semilatent hordeivirus (pslv) triple gene block (tgb), 15k tgbp2 and 18k tgbp3. gfp-15k transiently expressed in nicotiana benthamiana leaf epidermal cells was associated with the endomembrane system elements. gfp-18k appeared in the membrane bodies at cell periphery. mutation analysis demonstrated that subcellular targeting of gfp-15k depended on the p ... | 2000 | 10725204 |
| 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 |
| suppression of post-transcriptional gene silencing by a plant viral protein localized in the nucleus. | post-transcriptional gene silencing (ptgs) is a homology-dependent rna degradation process that may target rna exclusively in the cytoplasm. in plants, ptgs functions as a natural defense mechanism against viruses. we reported previously that the 2b protein encoded by cucumber mosaic cucumovirus (cmv) is a virulence determinant and a suppressor of ptgs initiation in transgenic nicotiana benthamiana. by fusion with the green fluorescent protein, we now show that the cmv 2b protein localizes to th ... | 2000 | 10747034 |
| clones of cotton leaf curl geminivirus induce symptoms atypical of cotton leaf curl disease. | the causative agent of cotton leaf curl disease has previously been shown to be transmissible by the whitefly bemisia tabaci (gennadius) and a begomovirus (geminiviridae) was shown to be associated with the disease. this virus was provisionally called cotton leaf curl virus (clcuv) although no causal relationship between virus and disease was shown. in the present study full-length clones of clcuv, equivalent to the dna a component of bipartite begomoviruses, were obtained. the clones of clcuv w ... | 2000 | 10766303 |
| 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 |
| rotavirus vp6 expressed by pvx vectors in nicotiana benthamiana coats pvx rods and also assembles into viruslike particles. | the rotavirus major inner capsid protein (vp6) has been expressed in nicotiana benthamiana plants using vectors based on potato virus x (pvx). vp6 was expressed either as a fusion with the pvx coat protein or from an additional subgenomic promoter inserted to enable both vp6 and pvx coat protein to be expressed independently. both approaches yielded vp6, which retained the ability to form trimers. vp6 expressed from the subgenomic promoter assembled into paracrystalline sheets and tubes. express ... | 2000 | 10793003 |
| virus-induced silencing of a plant cellulose synthase gene. | specific cdna fragments corresponding to putative cellulose synthase genes (cesa) were inserted into potato virus x vectors for functional analysis in nicotiana benthamiana by using virus-induced gene silencing. plants infected with one group of cdnas had much shorter internode lengths, small leaves, and a "dwarf" phenotype. consistent with a loss of cell wall cellulose, abnormally large and in many cases spherical cells ballooned from the undersurfaces of leaves, particularly in regions adjacen ... | 2000 | 10810144 |
| rapid production of the major birch pollen allergen bet v 1 in nicotiana benthamiana plants and its immunological in vitro and in vivo characterization. | type i allergies are immunological disorders that afflict a quarter of the world's population. improved diagnosis of allergic diseases and the formulation of new therapeutic approaches are based on the use of recombinant allergens. we describe here for the first time the application of a rapid plant-based expression system for a plant-derived allergen and its immunological characterization. we expressed our model allergen bet v 1, the major birch pollen allergen, in the tobacco-related species n ... | 2000 | 10877820 |
| a single chimeric transgene derived from two distinct viruses confers multi-virus resistance in transgenic plants through homology-dependent gene silencing. | we showed previously that 218 and 110 bp n gene segments of tomato spotted wilt virus (tswv) that were fused to the non-target green fluorescent protein (gfp) gene were able to confer resistance to tswv via post-transcriptional gene silencing (ptgs). n gene segments expressed alone did not confer resistance. apparently, the gfp dna induced ptgs that targetted n gene segments and the incoming homologous tswv for degradation, resulting in a resistant phenotype. these observations suggested that mu ... | 2000 | 10900050 |
| 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 |
| tobacco mosaic virus replicase-mediated cross-protection: contributions of rna and protein-derived mechanisms. | specific sequences of the tobacco mosaic virus (tmv) rna-dependent rna-polymerase (rdrp) gene were investigated for their ability to confer cross-protection. nine overlapping segments ranging from 713 to 1070 nucleotides in length and covering the methyltransferase, helicase, and polymerase (pol) domains of the tmv rdrp open reading frame were systemically expressed in nicotiana benthamiana using a potato x virus (pvx) vector [chapman, s., kavanagh, t., and baulcombe, d. c. (1992). plant j., 1, ... | 2000 | 10915597 |
| vascular invasion routes and systemic accumulation patterns of tobacco mosaic virus in nicotiana benthamiana. | plant viruses must enter the host vascular system in order to invade the young growing parts of the plant rapidly. functional entry sites into the leaf vascular system for rapid systemic infection have not been determined for any plant/virus system. tobacco mosaic virus (tmv) entry into minor, major and transport veins from non-vascular cells of nicotiana benthamiana in source tissue and its exit from veins in sink tissue was studied using a modified virus expressing green fluorescent protein (g ... | 2000 | 10929128 |
| delayed activation of post-transcriptional gene silencing and de novo transgene methylation in plants with the coat protein gene of sweet potato feathery mottle potyvirus. | the relationship between post-transcriptional gene silencing (ptgs) and dna methylation was examined using nicotiana benthamiana transformed with the coat protein gene including the 3' non-translated region of sweet potato feathery mottle potyvirus. line 4.28 showed a delayed activation of the transgene silencing in comparison with the other silenced lines, and showed complete resistance against the recombinant potato virus x engineered to contain the sequence homologous to the transgene when th ... | 2000 | 10936519 |
| analysis of transgenic grapevine (vitis rupestris) and nicotiana benthamiana plants expressing an arabis mosaic virus coat protein gene. | a disarmed lba4404 strain of agrobacterium tumefaciens harboring a binary vector which contained chimeric genes encoding the neomycin phosphotransferase (npt ii) and the coat protein (cp) of arabis mosaic nepovirus (armv) was used in co-cultivation experiments with leaf discs of nicotiana benthamiana and somatic embryos of the grapevine rootstock cultivar vitis rupestris. transgenic n. benthamiana expressing the armv cp gene were regenerated and six independent lines were characterized. enzyme-l ... | 2000 | 10936531 |