Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
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| sida micrantha mosaic is associated with a complex infection of begomoviruses different from abutilon mosaic virus. | we report on the nucleotide sequences of geminiviruses of the genus bemogovirus infecting sida micrantha schr., a common weed in brazil. for decades, the mosaic frequently associated with sida plants was considered to be caused by a brazilian strain of abutilon mosaic virus (abmv). by infection studies and sequence comparisons, we demonstrate that it is associated with a complex of at least two begomoviruses as different from abmv as most south american geminiviruses. two molecules of dna a (a1, ... | 2004 | 15045569 |
| functional analysis of the final steps of the 1-deoxy-d-xylulose 5-phosphate (dxp) pathway to isoprenoids in plants using virus-induced gene silencing. | isoprenoid biosynthesis in plant plastids occurs via the 1-deoxy-d-xylulose 5-phosphate (dxp) pathway. we used tobacco rattle virus (trv) to posttranscriptionally silence the expression of the last two enzymes of this pathway, the ispg-encoded (e)-4-hydroxy-3-methylbut-2-enyl diphosphate synthase (hds) and the isph-encoded isopentenyl/dimethylallyl diphosphate synthase (idds), as well as isopentenyl/dimethylallyl diphosphate isomerase (idi), the enzyme that interconverts ipp and dmapp. trv-ispg ... | 2004 | 15064370 |
| a geminivirus ayvv-derived shuttle vector for tobacco by2 cells. | we have developed a plant- escherichia coli pasv shuttle vector from the essential elements of the ageratum yellow vein virus (ayvv). the geminivirus vector contains the ayvv genome with the coat-protein deletion, the e. coli vector backbone of puc19, a unique cloning site and gene expression cassettes for plant selection and reporter gene activity. the replication of pasv vectors was compared in nicotiana benthamiana and n. tabacum by2 cells, and the latter were found to be suitable for long-te ... | 2004 | 15069580 |
| salicylic acid is part of the mi-1-mediated defense response to root-knot nematode in tomato. | the mi-1 gene of tomato confers resistance against three species of root-knot nematode in tomato (lycopersicon esculentum). transformation of tomato carrying mi-1 with a construct expressing nahg, which encodes salicylate hydroxylase, a bacterial enzyme that degrades salicylic acid (sa) to catechol, results in partial loss of resistance to root-knot nematodes. exogenous sa was toxic to roots expressing nahg but not to control roots. this toxicity is most likely due to the production of catechol ... | 2004 | 15077667 |
| a natural variant of a host rna-dependent rna polymerase is associated with increased susceptibility to viruses by nicotiana benthamiana. | nicotiana benthamiana often displays more intense symptoms after infection by rna viruses than do other nicotiana species. here, we examined the role of rna-dependent rna polymerases (rdrps) in n. benthamiana antiviral defense. cdnas representing only two genes encoding rdrps were identified in n. benthamiana. one rdrp was similar in sequence to sde1/sgs2 required for maintenance of transgene silencing, whereas the second, named nbrdrp1m, was >90% identical in sequence to the salicylic acid (sa) ... | 2004 | 15079073 |
| potato virus x-induced gene silencing in leaves and tubers of potato. | virus induced gene silencing (vigs) is increasingly used to generate transient loss-of-function assays and has potential as a powerful reverse-genetics tool in functional genomic programs as a more rapid alternative to stable transformation. a previously described potato virus x (pvx) vigs vector has been shown to trigger silencing in the permissive host nicotiana benthamiana. this paper demonstrates that a pvx-based vigs vector is also effective in triggering a vigs response in both diploid and ... | 2004 | 15084725 |
| phloem specific expression driven by wheat dwarf geminivirus v-sense promoter in transgenic dicotyledonous species. | wheat dwarf geminivirus (wdv) is a single-stranded dna mastrevirus. the large intergenic region (lir) of wdv contains cis-acting elements essential for the replication of the genome as well as for the bidirectional transcription of virus genes. the lir was fused to the gus (uida) reporter gene and the wdv viral sense (v-sense) promoter activity derived from the stable integration of that promoter was analysed in transgenic dicot plants. various dicot species were tested, including nicotiana taba ... | 2004 | 15086824 |
| expression of the b subunit of the heat-labile enterotoxin of escherichia coli in tobacco mosaic virus-infected nicotiana benthamiana plants and its characterization as mucosal immunogen and adjuvant. | we have produced biologically active recombinant (r) ltb, the nontoxic b subunit of heat-labile toxin (lt) of escherichia coli in tobacco mosaic virus (tmv)-infected nicotiana benthamiana plants. we amplified the ltb encoding sequence with its leader and introduced a hexahistidyl tag and an endoplasmic reticulum retention signal. the resulting product was ligated into a tmv-based plant viral expression vector that was used for the generation of recombinant viral rna. eighty-nine percent of n. be ... | 2004 | 15099768 |
| rice dwarf phytoreovirus segment s6-encoded nonstructural protein has a cell-to-cell movement function. | rice dwarf virus (rdv) is a member of the genus phytoreovirus, which is composed of viruses with segmented double-stranded rna genomes. proteins that support the intercellular movement of these viruses in the host have not been identified. microprojectile bombardment was used to determine which open reading frames (orfs) support intercellular movement of a heterologous virus. a plasmid containing an infectious clone of potato virus x (pvx) defective in cell-to-cell movement and expressing either ... | 2004 | 15113917 |
| silencing of subfamily i of protein phosphatase 2a catalytic subunits results in activation of plant defense responses and localized cell death. | the central importance of protein phosphorylation in plant defense responses has been demonstrated by the isolation of several disease-resistance genes that encode protein kinases. in addition, there are many reports of changes in protein phosphorylation accompanying plant responses to pathogens. in contrast, little is known about the role of protein dephosphorylation in regulating plant defenses. we report that expression of the lepp2ac1 gene, which encodes a catalytic subunit of the heterotrim ... | 2004 | 15125764 |
| citrx thioredoxin interacts with the tomato cf-9 resistance protein and negatively regulates defence. | to identify proteins involved in tomato cf-9 resistance protein function, a yeast two-hybrid screen was undertaken using the cytoplasmic c-terminus of cf-9 as bait. a thioredoxin-homologous clone, interacting specifically with cf-9, was identified and called citrx (cf-9-interacting thioredoxin). virus-induced gene silencing (vigs) of citrx resulted in an accelerated cf-9/avr9-triggered hypersensitive response in both tomato and nicotiana benthamiana, accompanied by enhanced accumulation of react ... | 2004 | 15131698 |
| a modified viral satellite dna that suppresses gene expression in plants. | dnabeta is a type of single-stranded (ss) circular satellite dna found in association with monopartite-genome begomoviruses, such as tomato yellow leaf curl china virus isolate y10 (tylccnv-y10). y10 dnabeta is required for symptom expression in plants but depends on tylccnv-y10 genomic dna (dna-a) for replication and encapsidation. when we converted dnabeta into a gene-silencing vector (modified dnabeta (dnambeta)) by replacing its c1 open-reading frame (orf) with a multiple cloning site (mcs), ... | 2004 | 15144385 |
| analysis of thermal stress-mediated pstvd variation and biolistic inoculation of progeny of viroid "thermomutants" to tomato and brassica species. | thermal stress of pstvd-infected nicotiana benthamiana led to appearance of a broad pstvd sequence distribution, where most of mutations accumulated in the left half of the viroid's secondary structure including the "pathogenicity" domain. a similar effect had been reported for hop latent viroid [virology 287 (2001) 349]. the pool of viroid "thermomutants" progenies was transcribed into cdna and used for biolistic inoculation of raphanus sativa, where the pstvd infection was detectable by revers ... | 2004 | 15165815 |
| molecular characterization of nbchmp1 encoding a homolog of human chmp1 in nicotiana benthamiana. | in humans, chmp1 encodes a protein of dual function that plays a role in both modification of chromatin structure and endosomal vesicle trafficking. recently, it was found that sal1, a chmp1 homolog in maize, is important for the development of the aleurone cell layers in maize endosperm. in this study, we investigated the structure and function of a nicotiana benthamiana chmp1 homolog designated nbchmp1. nbchmp1 encodes a small protein with a bipartite nuclear localization signal at its n-termi ... | 2004 | 15179039 |
| a method of high frequency virus-induced gene silencing in chili pepper (capsicum annuum l. cv. bukang). | using a tobacco rattle virus (trv)-based virus-induced gene silencing (vigs) system, expression of phytogene desaturase (pds) and ribulose-1,5-bisphosphate carboxylase small-subuit (rbcs) genes was suppressed in nicotiana benthamiana and pepper plants (capsicum annuum l. cv. bukang). the silenced phenotypes of pale yellow (rbcs), and photobleached leaves (pds), were invariably obvious 2 weeks after inoculation with the trv-based vector. in a parallel experiment, the same set of genes was silence ... | 2004 | 15179058 |
| the dna beta satellite component associated with ageratum yellow vein disease encodes an essential pathogenicity protein (betac1). | ageratum yellow vein disease (ayvd) is caused by the geminivirus ageratum yellow vein virus (ayvv) and an associated dna beta satellite. we have mapped a dna beta transcript to a highly conserved open reading frame (betac1 orf). the most abundant transcript 5'-terminus is located 8 bases upstream of the betac1 orf putative initiation codon while the transcript terminates at multiple sites downstream from the putative termination codon. disruption of betac1 protein expression by the introduction ... | 2004 | 15183051 |
| geminate structures of african cassava mosaic virus. | two types of geminate structures were purified from african cassava mosaic geminivirus (acmv)-infected nicotiana benthamiana plants and analyzed by electron cryomicroscopy and image reconstruction. after cesium sulfate density gradient centrifugation, they were separated into lighter top (t) and heavier bottom (b) components. t particles comigrated with host proteins, whereas b particles were concentrated in a cesium density typical for complete virions. both particles were composed of two incom ... | 2004 | 15194750 |
| single-chain antibodies against a plant viral rna-dependent rna polymerase confer virus resistance. | crop loss due to viral diseases is still a major problem for agriculture today. we present a strategy to achieve virus resistance based on the expression of single-chain fv fragments (scfvs) against a conserved domain in a plant viral rna-dependent rna polymerase (rdrp), a key enzyme in virus replication. the selected scfvs inhibited complementary rna synthesis of different plant virus rdrps in vitro and virus replication in planta. moreover, the scfvs also bound to the rdrp of the distantly rel ... | 2004 | 15195103 |
| molecular characterization of a melon necrotic spot virus strain that overcomes the resistance in melon and nonhost plants. | resistance of melon (cucumis melo l.) to melon necrotic spot virus (mnsv) is inherited as a single recessive gene, denoted nsv. no mnsv isolates described to date (e.g., mnsv-malpha5), except for the mnsv-264 strain described here, are able to overcome the resistance conferred by nsv. analysis of protoplasts of susceptible (nsv/-) and resistant (nsv/nsv) melon cultivars inoculated with mnsv-264 or mnsv-malpha5 indicated that the resistance trait conferred by this gene is expressed at the single- ... | 2004 | 15195949 |
| short interfering rna accumulation correlates with host recovery in dna virus-infected hosts, and gene silencing targets specific viral sequences. | viruses are both inducers and targets of posttranscriptional gene silencing (ptgs), a natural defense mechanism in plants. here we report molecular evidence of the ability of single-stranded dna (ssdna) viruses to induce ptgs in infected plants irrespective of the severity of or recovery from the symptoms. our results reveal that five distinct species of cassava-infecting geminiviruses were capable of triggering ptgs by producing two classes of virus-specific short interfering rnas (sirnas) of 2 ... | 2004 | 15220420 |
| virus-induced gene silencing in solanum species. | virus-induced gene silencing (vigs) has been used routinely in nicotiana benthamiana to assess functions of candidate genes and as a way to discover new genes required for diverse pathways, especially disease resistance signalling. vigs has recently been shown to work in arabidopsis thaliana and in tomato. here, we report that vigs using the tobacco rattle virus (trv) viral vector can be used in several solanum species, although the choice of vector and experimental conditions vary depending on ... | 2004 | 15225290 |
| mutation of phe50 to ser50 in the 126/183-kda proteins of odontoglossum ringspot virus abolishes virus replication but can be complemented and restored by exact reversion. | sequence comparison of a non-biologically active full-length cdna clone of odontoglossum ringspot virus (orsv) pot1 with a biologically active orsv cdna clone pot2 revealed a single nucleotide change of t-->c at position 211. this resulted in the change of phe50 in ot2 to ser50 in ot1. it was not the nucleotide but the amino acid change of phe50 that was responsible for the inability of ot1 to replicate. time-course experiments showed that no minus-strand rna synthesis was detected in mutants wi ... | 2004 | 15269387 |
| vdnep, an elicitor from verticillium dahliae, induces cotton plant wilting. | verticillium wilt is a vascular disease of cotton. the causal fungus, verticillium dahliae, secretes elicitors in culture. we have generated approximately 1,000 5'-terminal expressed sequence tags (ests) from a cultured mycelium of v. dahliae. a number of ests were found to encode proteins harboring putative signal peptides for secretion, and their cdnas were isolated. heterologous expression led to the identification of a protein with elicitor activities. this protein, named v. dahliae necrosis ... | 2004 | 15294839 |
| relocalization of nuclear aly proteins to the cytoplasm by the tomato bushy stunt virus p19 pathogenicity protein. | the p19 protein of tomato bushy stunt virus (tbsv) is a multifunctional pathogenicity determinant involved in suppression of posttranscriptional gene silencing, virus movement, and symptom induction. here, we report that p19 interacts with the conserved rna-binding domain of an as yet uncharacterized family of plant aly proteins that, in animals, are involved in export of rnas from the nucleus and transcriptional coactivation. we show that the four aly proteins encoded by the arabidopsis genome ... | 2004 | 15299117 |
| transient coexpression of individual genes encoded by the triple gene block of potato mop-top virus reveals requirements for tgbp1 trafficking. | tgbp1, tgbp2, and tgbp3, three plant virus movement proteins encoded by the "triple gene block" (tgb), may act in concert to facilitate cell-to-cell transport of viral rna genomes. transient expression of potato mop-top virus (genus pomovirus) movement proteins was used as a model to reconstruct interactions between tgb proteins. in bombarded epidermal cells of nicotiana benthamiana, green fluorescent protein (gfp)-tgbp1 was distributed uniformly. however, in the presence of tgbp2 and tgbp3, gfp ... | 2004 | 15305613 |
| preparation of polyclonal antibodies of rubisco large and small subunits and their application in the functional analysis of the genes. | spinach rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase) large (rbcl) and small (rbcs) subunits were separated by sds-page, and protein amount and purity were determined by bradford assay. polyclonal antibodies against rbcl and rbcs subunit were generated in female balb/c mice and had no cross-reaction with each other. a total of 81 microg antigens were used and 0.3 ml anti-sera with titer of 1:5000 were yielded. the antibodies were also applicable to study rbcl and rbcs in tobacco plan ... | 2004 | 15346203 |
| virus induced gene silencing of a deficiens ortholog in nicotiana benthamiana. | traditionally, developmental studies in plant biology have suffered from the lack of a convenient means to study gene function in non-model plant species. here we show that virus-induced gene silencing (vigs) is an effective new tool to study the function of orthologs of floral homeotic genes such as deficiens (def) in non-model systems. we used a tobacco rattle virus (trv)-based vigs approach to study the function of the nicotiana benthamiana def ortholog (nbdef). silencing of nbdef in n. benth ... | 2004 | 15356389 |
| tête à tête of tomato yellow leaf curl virus and tomato yellow leaf curl sardinia virus in single nuclei. | since 1997 two distinct geminivirus species, tomato yellow leaf curl sardinia virus (tylcsv) and tomato yellow leaf curl virus (tylcv), have caused a similar yellow leaf curl disease in tomato, coexisted in the fields of southern spain, and very frequently doubly infected single plants. tomatoes as well as experimental test plants (e.g., nicotiana benthamiana) showed enhanced symptoms upon mixed infections under greenhouse conditions. viral dna accumulated to a similar extent in singly and doubl ... | 2004 | 15367638 |
| dna gyrase is involved in chloroplast nucleoid partitioning. | dna gyrase, which catalyzes topological transformation of dna, plays an essential role in replication and transcription in prokaryotes. virus-induced gene silencing of nbgyra or nbgyrb, which putatively encode dna gyrase subunits a and b, respectively, resulted in leaf yellowing phenotypes in nicotiana benthamiana. nbgyra and nbgyrb complemented the gyra and gyrb temperature-sensitive mutations of escherichia coli, respectively, which indicates that the plant and bacterial subunits are functiona ... | 2004 | 15367714 |
| preserved antigenicity of hiv-1 p24 produced and purified in high yields from plants inoculated with a tobacco mosaic virus (tmv)-derived vector. | production of structural proteins from foot-and-mouth disease virus (fmdv) and bovine herpes virus (bhv-1) in nicotiana benthamiana through the use of a tobacco mosaic virus-based vector (tmv-30b) has been reported previously. the development of the tmv-30b-hisc vector, a new version that adds a c-terminal histidine (his) sequence to the foreign protein expressed is described. coding sequences from the fmdv vpl protein and the core protein, p24, from a clade c hiv-1 isolate from zambia were clon ... | 2004 | 15381357 |
| agrodrench: a novel and effective agroinoculation method for virus-induced gene silencing in roots and diverse solanaceous species. | summary virus-induced gene silencing (vigs) is an extremely powerful tool for plant functional genomics. we used tobacco rattle virus (trv)-derived vigs vectors expressed from binary vectors within agrobacterium to induce rna silencing in plants. leaf infiltration is the most common method of agroinoculation used for vigs but this method has limitations as it is laborious for large-scale screening and some plants are difficult to infiltrate. here we have developed a novel and simple method of ag ... | 2004 | 15447657 |
| expression of tombusvirus open reading frames 1 and 2 is sufficient for the replication of defective interfering, but not satellite, rna. | yeast cells co-expressing the replication proteins p36 and p95 of carnation italian ringspot virus (cirv) support the rna-dependent replication of several defective interfering (di) rnas derived from either the genome of cirv or the related cymbidium ringspot virus (cymrsv), but not the replication of a satellite rna (sat rna) originally associated with cymrsv. di, but not sat rna, was replicated in yeast cells co-expressing both di and sat rna. using transgenic nicotiana benthamiana plants cons ... | 2004 | 15448375 |
| orf6 of tobacco mosaic virus is a determinant of viral pathogenicity in nicotiana benthamiana. | tobacco mosaic virus (tmv) contains a sixth open reading frame (orf6) that potentially encodes a 4.8 kda protein. elimination of orf6 from tmv attenuated host responses in nicotiana benthamiana without alteration in virus accumulation. furthermore, heterologous expression of tmv orf6 from either potato virus x (pvx) or tobacco rattle virus (trv) vectors enhanced the virulence of both viruses in n. benthamiana, also without effects on their accumulation. by contrast, the presence or absence of tm ... | 2004 | 15448376 |
| potato virus x tgbp1 induces plasmodesmata gating and moves between cells in several host species whereas cp moves only in n. benthamiana leaves. | experiments were conducted to compare the plasmodesmal transport activities of potato virus x (pvx) tgbp1 and coat protein (cp) in several plant species. microinjection experiments indicated that tgbp1 gates plasmodesmata in nicotiana tabacum leaves. these results support previous microinjection studies indicating that tgbp1 gates plasmodesmata in nicotiana benthamiana and nicotiana clevelandii leaves. to study protein movement, plasmids expressing the green fluorescent protein (gfp) gene fused ... | 2004 | 15464839 |
| hoppton is a pseudomonas syringae hrp (type iii secretion system) cysteine protease effector that suppresses pathogen-induced necrosis associated with both compatible and incompatible plant interactions. | pseudomonas syringae pv. tomato dc3000 causes bacterial speck disease in tomato, and it elicits the hypersensitive response (hr) in non-host plants such as nicotiana tabacum and nicotiana benthamiana. the compatible and incompatible interactions of dc3000 with tomato and nicotiana spp., respectively, result in plant cell death, but the hr cell death occurs more rapidly and is associated with effective plant defense. both interactions require the hrp (hr and pathogenicity) type iii secretion syst ... | 2004 | 15469508 |
| unaltered complex n-glycan profiles in nicotiana benthamiana despite drastic reduction of beta1,2- n -acetylglucosaminyltransferase i activity. | udp-glcnac:alpha3-d-mannoside beta1,2- n -acetylglucosaminyltransferase i (gnti; ec 2.4.1.101) is a golgi-resident glycosyltransferase that is essential for the processing of oligomannose to hybrid and complex n-glycans in higher eukaryotes. the cdna of nicotiana tabacum gnti has been cloned and characterised previously. to assess the influence of gnti expression levels on the formation of complex n-glycans we used posttranscriptional gene silencing to knock down the expression of gnti in the to ... | 2004 | 15486460 |
| gene silencing from plant dna carried by a geminivirus. | the geminivirus tomato golden mosaic virus (tgmv) replicates in nuclei and expresses genes from high copy number dna episomes. the authors used tgmv as a vector to determine whether episomal dna can cause silencing of homologous, chromosomal genes. two markers were used to asses silencing: (1) the sulfur allele (su) of magnesium chelatase, an enzyme required for chlorophyll formation; and (2) the firefly luciferase gene (luc). various portions of both marker genes were inserted into tgmv in plac ... | 1998 | 15494056 |
| a conserved secondary structure in the hypervariable region at the 5' end of bamboo mosaic virus satellite rna is functionally interchangeable. | satellite rna (satrna) associated with bamboo mosaic virus (bamv) is dependent on bamv for replication and encapsidation. molecular analyses of total rna extracted from bamboo species collected worldwide revealed that 26 out of 61 bamv isolates harbored satbamv. among them, two phylogenetically distinguishable groups, a and b, with a genetic diversity of 6.9 +/- 0.7% were identified. greatest sequence diversity occurred in the 5' untranslated region (utr) that contained one hypervariable region ... | 2004 | 15527838 |
| high-level expression of alternative oxidase protein sequences enhances the spread of viral vectors in resistant and susceptible plants. | the alternative oxidase (aox) is the terminal oxidase of the cyanide-resistant alternative respiratory pathway in plants and has been implicated in resistance to viruses. when tobacco mosaic virus (tmv) vectors were used to drive very high levels of expression of either aox or aox mutated in its active site (aox-e), virus spread was enhanced. this was visualized as the induction of larger hypersensitive-response lesions after inoculation onto nn-genotype tobacco than those produced by vectors be ... | 2004 | 15557251 |
| a dnabeta associated with tomato yellow leaf curl china virus is required for symptom induction. | we report here that all 25 isolates of tomato yellow leaf curl china virus (tylccnv) collected from tobacco, tomato, or siegesbeckia orientalis plants in different regions of yunnan province, china, were associated with dnabeta molecules. to investigate the biological role of dnabeta, full-length infectious clones of viral dna and dnabeta of tylccnv isolate y10 (tylccnv-y10) were agroinoculated into nicotiana benthamiana, nicotiana glutinosa, nicotiana. tabacum samsun (nn or nn), tomato, and pet ... | 2004 | 15564504 |
| gene shuffling-generated and natural variants of the tomato resistance gene cf-9 exhibit different auto-necrosis-inducing activities in nicotiana species. | tomato cf genes encode membrane-bound proteins with extracellular leucine-rich repeats, and confer resistance to the fungal tomato pathogen cladosporium fulvum, and a hypersensitive response (hr) to c. fulvum-derived race-specific elicitors. several cf genes, including cf-4 and cf-9, are members of the highly homologous hcr9 (homologues of c. fulvumresistance gene cf-9) gene family. hcr9s evolve mainly by sequence exchange between paralogues, by which novel cf genes may be generated. to mimic th ... | 2004 | 15584959 |
| efficient virus-induced gene silencing in roots using a modified tobacco rattle virus vector. | due to their capability of eliciting a form of posttranscriptional gene silencing (termed virus-induced gene silencing or vigs), plant viruses are increasingly used as reverse-genetics tools for functional characterization of plant genes. rna viruses have been shown to trigger silencing in a variety of host plants, including members of solanacae and arabidopsis (arabidopsis thaliana). several factors affect the silencing response, including host range and viral tropism within the plant. the work ... | 2004 | 15591447 |
| pseudomonas type iii effector avrpto suppresses the programmed cell death induced by two nonhost pathogens in nicotiana benthamiana and tomato. | many gram-negative bacterial pathogens rely on a type iii secretion system to deliver a number of effector proteins into the host cell. though a number of these effectors have been shown to contribute to bacterial pathogenicity, their functions remain elusive. here we report that avrpto, an effector known for its ability to interact with pto and induce pto-mediated disease resistance, inhibited the hypersensitive response (hr) induced by nonhost pathogen interactions. pseudomonas syringae pv. to ... | 2004 | 15597738 |
| dissecting rna silencing in protoplasts uncovers novel effects of viral suppressors on the silencing pathway at the cellular level. | short interfering rna (sirna)-mediated rna silencing plays an important role in cellular defence against viral infection and abnormal gene expression in multiple organisms. many viruses have evolved silencing suppressors for counter-defence. we have developed an rna silencing system in the protoplasts of nicotiana benthamiana to investigate the functions of viral suppressors at the cellular level. we showed that rna silencing against a green fluorescent protein (gfp) reporter gene in the protopl ... | 2004 | 15601991 |
| rapid one-step protein purification from plant material using the eight-amino acid strepii epitope. | beyond the rewards of plant genome analysis and gene identification, characterisation of protein activities, post-translational modifications and protein complex composition remains a challenge for plant biologists. ideally, methods should allow rapid isolation of proteins from plant material achieving a high degree of purity. we tested three purification strategies based on the eight-amino acid strepii, six-amino acid his(6) and 181-amino acid tandem affinity purification (tap) affinity tags fo ... | 2004 | 15604670 |
| pvx-cre-mediated marker gene elimination from transgenic plants. | cre recombinase gene from bacteriophage p1 was transiently expressed by a potato virus x (pvx)-based vector in transgenic lox -target nicotiana benthamiana plants to remove the selectable marker gene. the target construct consisted of two directly oriented lox sites flanking a bar gene located between a gfp coding region and an upstream camv 35s promoter. the cre-mediated excision of intervening sequence placed the gfp coding region under the transcriptional control of the camv 35s promoter. gfp ... | 2004 | 15604695 |
| the nuclear localization of the arabidopsis transcription factor tip is blocked by its interaction with the coat protein of turnip crinkle virus. | we have previously reported that tip, an arabidopsis protein, interacts with the coat protein (cp) of turnip crinkle virus (tcv) in yeast cells and that this interaction correlated with the resistance response in the tcv-resistant arabidopsis ecotype dijon-17. tip was also able to activate transcription of reporter genes in yeast cells, suggesting that it is likely a transcription factor. we have now verified the physical interaction between tip and tcv cp in vitro and showed that cp mutants una ... | 2005 | 15629774 |
| a geminivirus-induced gene silencing system for gene function validation in cassava. | we have constructed an african cassava mosaic virus (acmv) based gene-silencing vector as a reverse genetics tool for gene function analysis in cassava. the vector carrying a fragment from the nicotiana tabacum sulfur gene (su), encoding one unit of the chloroplast enzyme magnesium chelatase, was used to induce the silencing of the cassava orthologous gene resulting in yellow-white spots characteristic of the inhibition of su expression. this result suggests that well developed sequence database ... | 2004 | 15630624 |
| expression of a begomoviral dnabeta gene in transgenic nicotiana plants induced abnormal cell division. | an increasing number of monopartite begomoviruses are being identified that a satellite molecule (dnabeta) is required to induce typical symptoms in host plants. dnabeta encodes a single gene (termed betac1) encoded in the complementary-sense. we have produced transgenic nicotiana benthamiana and n. tabacum plants expressing the betac1 gene of a dnabeta associated with tomato yellow leaf curl china virus (tylccnv), under the control of the cauliflower mosaic virus 35s promoter. transgenic plants ... | 2005 | 15633241 |
| interaction between a nanovirus-like component and the tobacco curly shoot virus/satellite complex. | the biological role of dna1, a nanovirus-like component shown to be associated with the begomovirus/satellite complex, has not yet been identified. here, we demonstrated that dna1 of tobacco curly shoot virus isolate y35 (tbcsv-y35) attenuated leaf-curling symptoms induced by tbcsv-y35 or tbcsv-y35 plus y35 dnabeta in the early stage of symptom development and induced leaf cluster at a later stage of symptom development in nicotiana benthamiana plants. the leaf disc assay demonstrated that tbcsv ... | 2005 | 15645078 |
| construction and properties of a gene-silencing vector based on poplar mosaic virus (genus carlavirus). | a gene-silencing vector based on a full-length genomic clone of poplar mosaic virus (popmv) was constructed, with coat protein and movement protein genes removed, and containing instead, the coding sequence for green fluorescent protein (gfp). this paper demonstrates that the popmv-derived gene-silencing vector was able to silence gfp expression in gfp transgenic nicotiana benthamiana plants. the full-length genome of an oxford isolate of popmv (pv275) was cloned and sequenced. a full-length pop ... | 2004 | 15664047 |
| mimicking carboxyterminal phosphorylation differentially effects subcellular distribution and cell-to-cell movement of tobacco mosaic virus movement protein. | phosphorylation of tobacco mosaic virus movement protein (tmv-mp) at three carboxyterminal ser/thr sites negatively regulates tmv-mp gating function and viral spread in nicotiana tabacum but not in nicotiana benthamiana, indicating a host dependant inactivation strategy. here, we examine the effect of mimicking carboxyterminal phosphorylation on cell-to-cell transport of tmv-mp protein itself in host plants nicotiana clevelandii, n. benthamiana, nicotiana glutinosa and n. tabacum. since tmv-mp t ... | 2005 | 15680421 |
| suppression of rna silencing by a geminivirus nuclear protein, ac2, correlates with transactivation of host genes. | bipartite geminiviruses encode a small protein, ac2, that functions as a transactivator of viral transcription and a suppressor of rna silencing. a relationship between these two functions had not been investigated before. we characterized both of these functions for ac2 from mungbean yellow mosaic virus-vigna (mymv). when transiently expressed in plant protoplasts, mymv ac2 strongly transactivated the viral promoter; ac2 was detected in the nucleus, and a split nuclear localization signal (nls) ... | 2005 | 15681452 |
| the lettuce infectious yellows virus (liyv)-encoded p26 is associated with plasmalemma deposits within liyv-infected cells. | cytological, immunological, and mutagenesis approaches were used to identify the viral factors associated with the formation of plasmalemma deposits (plds) in whole plants and protoplasts infected by lettuce infectious yellows virus (liyv). transmission electron microscopy and immunogold labeling using polyclonal antibodies to four of the five liyv rna 2-encoded large proteins, capsid protein (cp), minor capsid protein (cpm), hsp70 homolog (hsp70h), and p59, showed specific labeling of liyv viri ... | 2005 | 15721368 |
| analysis of tombusvirus revertants to identify essential amino acid residues within rna-dependent rna polymerase motifs. | the rna-dependent rna polymerase (rdrp) of tomato bushy stunt virus (tbsv) contains an arginine- and proline-rich (rpr) motif. this motif functions as an rna-binding domain and is essential for tombusvirus replication. a mutant carrying three arginine substitutions in this motif rendered the virus unable to replicate in nicotiana benthamiana plants and protoplasts. when the replicase function was provided in trans, by expressing the tbsv rdrp in n. benthamiana plants, an infectious variant could ... | 2005 | 15722545 |
| expression of single-chain antibodies in transgenic plants. | there is an ever-growing interest in plant molecular farming as a system for producing valuable recombinant pharmaceutical molecules, such as single-chain variable fragments, on an industrial/agricultural scale and it appears that it is going to become a reality. human epidermal growth factor receptor-2 (her2) is an oncogene involved in abnormal cell growth in breast cancer and is considered for the development of new cancer therapies. we describe here the cloning and expression of a scfv-alpha ... | 2005 | 15734049 |
| the conserved xanthomonas campestris pv. vesicatoria effector protein xopx is a virulence factor and suppresses host defense in nicotiana benthamiana. | nicotiana benthamiana leaves display a visible plant cell death response when infiltrated with a high titer inoculum of the non-host pathogen, xanthomonas campestris pv. vesicatoria (xcv). this visual phenotype was used to identify overlapping cosmid clones from a genomic cosmid library constructed from the xcv strain, gm98-38. individual cosmid clones from the xcv library were conjugated into x. campestris pv. campestris (xcc) and exconjugants were scored for an altered visual high titer inocul ... | 2005 | 15743446 |
| properties of a virus isolated from vernonia amygdalina del. in lagos, nigeria. | a previously uncharacterized virus tentatively named vernonia green vein-banding virus (vgvbv) was isolated from vernonia amygdalina del. ("bitterleaf") from lagos, nigeria. the virus was mechanically transmissible but had a narrow host range restricted to nicotiana benthamiana, chenopodium quinoa and c. amaranticolor. it was also transmissible in a non-persistent manner by myzus persicae. the virus was purified from n. benthamiana and about 750 nm long flexuous rod-shaped particles were observe ... | 2004 | 15745049 |
| subcellular localization and immunodetection of movement proteins of olive latent virus 1. | polyclonal sera raised to escherichia coli-expressed movement proteins encoded by orf 3 (p8k) and orf 4 (p6k) of olive latent virus 1, were used for their immunodetection in infected nicotiana benthamiana plants. in subfractionated locally infected tissues 4 days post inoculation (d.p.i.) that were analysed by western blot, p8k was found in the fast-sedimenting fractions p1 and p30 containing membranous material and/or cell organelles and, likely, the fibrous structures mentioned below, but not ... | 2005 | 15747053 |
| molecular genetic evidence for the role of sgt1 in the intramolecular complementation of bs2 protein activity in nicotiana benthamiana. | pepper plants (capsicum annuum) containing the bs2 resistance gene are resistant to strains of xanthomonas campestris pv vesicatoria (xcv) expressing the bacterial effector protein avrbs2. avrbs2 is delivered directly to the plant cell via the type iii protein secretion system (ttss) of xcv. upon recognition of avrbs2 by plants expressing the bs2 gene, a signal transduction cascade is activated leading to a bacterial disease resistance response. here, we describe a novel pathosystem that consist ... | 2005 | 15749757 |
| molecular basis for the rin4 negative regulation of rps2 disease resistance. | recent studies have demonstrated that rps2, a plasma membrane-localized nucleotide binding site/leucine-rich repeat protein from arabidopsis thaliana, associates with rpm1 interacting protein 4 (rin4) and that this association functions to modulate the rps2-mediated defense pathway in response to the bacterial effector protein avrrpt2. in addition to negatively regulating rps2 activity, rin4 is also a target of avrrpt2, a cys protease and cognate bacterial effector protein of rps2. nicotiana ben ... | 2005 | 15749765 |
| human-derived, plant-produced monoclonal antibody for the treatment of anthrax. | the unpredictable nature of bio-terrorism compels us to develop medical countermeasures that will enable authorities to treat individuals exposed to agents such as anthrax. we report the feasibility of producing a protective, human-derived, monoclonal antibody directed against the protective antigen (pa) of bacillus anthracis in plants. this was achieved by transient expression using agroinfiltration of nicotiana benthamiana plants. the resulting antibody was able to neutralize toxin activity in ... | 2005 | 15755575 |
| biological and molecular characterization of lettuce mosaic virus from tehran province in iran. | in this study, lettuce samples having lmv infection symptoms were collected from tehran fields during 2003. samples tested for lmv infection by immuno printing. three positive samples in immuno printing collected and their characteristics were determined. in mechanical inoculation, these isolates produced symptoms on chenopodium quinoa, c. amaranticolor, gomphrena globosa, nicotiana benthamiana, lactuca sativa cv. mantilia and cv. terocadero (which contains the mol1 resistance gene and susceptib ... | 2004 | 15756833 |
| pathogenicity and stability of a truncated dnabeta associated with tomato yellow leaf curl china virus. | dnabeta molecules are single-stranded satellite dna associated with monopartite begomoviruses (family geminiviridae). dnabeta possesses a c1 gene on the complementary strand, which has a conserved position and size. to better understand the function of c1 gene in virus infection, a c1 deletion dnabeta associated with a tomato yellow leaf curl china virus (tylccnv) isolate was constructed. co-agroinoculation with tylccnv showed the truncated dnabeta was infectious in nicotiana benthamiana and n. ... | 2005 | 15763146 |
| the nuclear shuttle protein of tomato leaf curl new delhi virus is a pathogenicity determinant. | the role of the movement protein (mp) and nuclear shuttle protein (nsp) in the pathogenicity of tomato leaf curl new delhi virus (tolcndv), a bipartite begomovirus, was studied. both genes were expressed in nicotiana benthamiana, nicotiana tabacum, and lycopersicon esculentum plants with the potato virus x (pvx) expression vector or by stable transformation of gene constructs under the control of the 35s promoter in n. tabacum. no phenotypic changes were observed in any of the three species when ... | 2005 | 15767443 |
| synthesis of infectious in vitro transcripts from cassia yellow blotch bromovirus cdna clones and a reassortment analysis with other bromoviruses in protoplasts. | cassia yellow blotch virus (cybv), genus bromovirus, was isolated from the australian native legume, cassia pleurocarpa, in western queensland, and its host range was found to be distinct from other bromoviruses. in this study, cybv was shown to infect systemically and efficiently a model plant species, arabidopsis thaliana, as we recently reported for another bromovirus, spring beauty latent virus (sblv). we constructed full-length cdna clones of cybv genomic rnas from which infectious in vitro ... | 2005 | 15770356 |
| differences in intensity and specificity of hypersensitive response induction in nicotiana spp. by inf1, inf2a, and inf2b of phytophthora infestans. | elicitins form a family of structurally related proteins that induce the hypersensitive response (hr) in plants, particularly nicotiana spp. the elicitin family is composed of several classes. most species of the plant-pathogenic oomycete genus phytophthora produce the well-characterized 10-kda canonical elicitins (class i), such as inf1 of the potato and tomato pathogen phytophthora infestans. two genes, inf2a and inf2b, encoding a distinct class (class iii) of elicitin-like proteins, also occu ... | 2005 | 15782632 |
| evidence that rna silencing-mediated resistance to beet necrotic yellow vein virus is less effective in roots than in leaves. | in plants, rna silencing is part of a defense mechanism against virus infection but there is little information as to whether rna silencing-mediated resistance functions similarly in roots and leaves. we have obtained transgenic nicotiana benthamiana plants encoding the coat protein readthrough domain open reading frame (54 kda) of beet necrotic yellow vein virus (bnyvv), which either showed a highly resistant or a recovery phenotype following foliar rub-inoculation with bnyvv. these phenotypes ... | 2005 | 15782633 |
| subcellular distribution of mutant movement proteins of cucumber mosaic virus fused to green fluorescent proteins. | the subcellular distribution of the movement proteins (mps) of nine alanine-scanning mutants of cucumber mosaic virus (cmv), fused to the green fluorescent protein (gfp) and expressed from cmv, was determined by confocal microscopy of infected epidermal cells of nicotiana tabacum and nicotiana benthamiana, as well as infected n. benthamiana protoplasts. only those mutant mps that were functional for movement in all host species tested localized to plasmodesmata of infected epidermal cells and to ... | 2005 | 15784916 |
| virus induction of heat shock protein 70 reflects a general response to protein accumulation in the plant cytosol. | different cytoplasmically replicating rna viruses were shown to induce a specific subset of heat-inducible heat shock protein 70 (hsp70) genes in arabidopsis (arabidopsis thaliana). to identify the inducing principle, a promoterreporter system was developed for the facile analysis of differentially responding arabidopsis hsp70 genes, by infiltration into nicotiana benthamiana leaves. through transient expression of individual viral cistrons or through deletion analysis of a viral replicon, we we ... | 2005 | 15805473 |
| dimerization of the bacterial effector protein avrbs3 in the plant cell cytoplasm prior to nuclear import. | the effector protein avrbs3 from the bacterial phytopathogen xanthomonas campestris pv. vesicatoria is translocated into the plant cell where it specifically induces hypertrophy symptoms or the hypersensitive reaction. activity of avrbs3 depends on nuclear localization signals (nlss) and an acidic activation domain, suggesting a role in regulation of plant transcription. here, we show that avrbs3 dimerizes in the plant cell prior to its nuclear import. avrbs3 deletion derivatives were tested in ... | 2005 | 15807781 |
| cotton leaf curl gezira virus-satellite dnas represent a divergent, geographically isolated nile basin lineage: predictive identification of a satdna rep-binding motif. | cotton leaf curl gezira virus (clcugv), a species of the genus begomovirus (family geminiviridae), was recently cloned from cotton, okra, and sida alba plants exhibiting leaf-curling and vein-thickening symptoms in sudan. here, we describe a previously unknown lineage of single-stranded dna satellite (satdna) molecules, which are associated with clcugv, and are required for development of characteristic disease symptoms. co-inoculation of cotton and nicotiana benthamiana plants with satdnas clon ... | 2004 | 15826909 |
| reciprocal function of movement proteins and complementation of long-distance movement of cymbidium mosaic virus rna by odontoglossum ringspot virus coat protein. | complementation of movement and coat proteins of the orchid-infecting potexvirus cymbidium mosaic virus (cymmv) and tobamovirus odontoglossum ringspot virus (orsv) was investigated. nicotiana benthamiana, which is susceptible to both cymmv and orsv, was used as a model system. four transgenic lines, each harbouring one of the movement protein (mp) or coat protein (cp) genes of cymmv or orsv, were constructed. the mp of cymmv consists of three overlapping open reading frames, together called the ... | 2005 | 15831968 |
| development of a candidate vaccine for newcastle disease virus by epitope display in the cucumber mosaic virus capsid protein. | a peptide fusion to the capsid protein (cp) of cucumber mosaic virus(cmv) was designed to express either a 17 amino acid (aa) neutralizing epitope of the newcastle disease virus (ndv) fusion (f) protein or an eight aa neutralizing epitope of the ndv hemagglutinin-neuraminidase (hn) protein. fusions of the f, hn and hn2 (duplicated hn epitope) were made in the internal betah-betai loop (motif 5) within the cmv cp. recombinant rna3 transcripts of the ixora strain of cmv were inoculated on to nicot ... | 2005 | 15834801 |
| induction of glutathione s-transferase genes of nicotiana benthamiana following infection by colletotrichum destructivum and c. orbiculare and involvement of one in resistance. | four glutathione s-transferase (gst) genes, nbgstu1, nbgstu2, nbgstu3, and nbgstf1, were amplified from cdna of nicotiana benthamiana leaves infected with colletotrichum destructivum using primers based on conserved regions of n. tabacum gst sequences. expression of nbgstu1 and nbgstu3 increased progressively during infection by either c. destructivum or colletotrichum orbiculare, except for a slight decrease by nbgstu1 late in the infection, whereas nbgstu2 and nbgstf1 expression remained relat ... | 2005 | 15837710 |
| [expression of tobacco skp1 gene induced by oligochitosan]. | oligochitosan is an effective inductor for plant resistance. to understand the induced resistance mechanism, mrna differential display was used to isolate genes from nicotiana tabacum var. samsun nn and four enhanced-expression gene fragments were obtained and were reamplified. the reamplified products of appropriate size were isolated and purified before they were subcloned into pmd18-t vector. the results of plasmids digestion by ecori and hindiii and analysis of reverse northern blot indicate ... | 2005 | 15840941 |
| eds1 in tomato is required for resistance mediated by tir-class r genes and the receptor-like r gene ve. | in tobacco and other solanaceae species, the tobacco n gene confers resistance to tobacco mosaic virus (tmv), and leads to induction of standard defense and resistance responses. here, we report the use of n-transgenic tomato to identify a fast-neutron mutant, sun1-1 (suppressor of n), that is defective in n-mediated resistance. induction of salicylic acid (sa) and expression of pathogenesis-related (pr) genes, each signatures of systemic acquired resistance, are both dramatically suppressed in ... | 2005 | 15842623 |
| a single amino acid residue of rna-dependent rna polymerase in the potato virus x genome determines the symptoms in nicotiana plants. | a potato virus x (pvx) strain, pvx-os, causes a necrotic mosaic in nicotiana benthamiana and ring spot mosaic in n. tabacum cv. samsunnn. by contrast, strain pvx-bs causes a mild mosaic in n. benthamiana and systemic asymptomatic infection in n. tabacum cv. samsunnn. to investigate the viral determinant of this difference, we produced various infectious cdna clones chimeric between these pvx genomes and clones with point mutations introduced by site-directed mutagenesis. inoculation tests with t ... | 2005 | 15845269 |
| development of a quantitative tool for measuring changes in the coefficient of conductivity of plasmodesmata induced by developmental, biotic, and abiotic signals. | the regulation of intercellular and interorgan communication is pivotal for cell fate decisions in plant development and probably plays a significant role in the systemic regulation of gene expression and in defense reactions against pathogens or other biotic and abiotic environmental factors. in plants, symplasmic cell-to-cell communication is provided by plasmodesmata (pd), coaxial membranous tunnels that span cell walls interconnecting adjacent cytoplasms. macromolecules, proteins, and rna ma ... | 2005 | 15868214 |
| viral class 1 rnase iii involved in suppression of rna silencing. | double-stranded rna (dsrna)-specific endonucleases belonging to rnase iii classes 3 and 2 process dsrna precursors to small interfering rna (sirna) or microrna, respectively, thereby initiating and amplifying rna silencing-based antiviral defense and gene regulation in eukaryotic cells. however, we now provide evidence that a class 1 rnase iii is involved in suppression of rna silencing. the single-stranded rna genome of sweet potato chlorotic stunt virus (spcsv) encodes an rnase iii (rnase3) ho ... | 2005 | 15890961 |
| characterization of the infectivity of bamboo mosaic virus with its correlation to the in vitro replicase activities in nicotiana benthamiana. | in vitro rna-dependent rna polymerase (rdrp) transcription assay share an extremely useful system for studying the molecular mechanisms of replication of positive-sense rna viruses such as bamboo mosaic virus (bamv). however, the obstacle encountered in this system is the inconsistency in the enzyme activity and the template specificity among different batches of the rdrp extracts. in order to overcome this obstacle, we designed experiments to study the functional dynamics of the bamv rdrp in te ... | 2005 | 15904988 |
| replication-independent expression of genome components and capsid protein of brome mosaic virus in planta: a functional role for viral replicase in rna packaging. | to begin elucidation of the relationship between brome mosaic virus (bmv) replication and encapsidation, we used a t-dna-based agrobacterium-mediated transient expression (agroinfiltration) system in nicotiana benthamiana leaves to express either individual or desired pairs of the three genomic rnas. the packaging competence of these rnas into virions formed by the transiently expressed coat protein (cp) was analyzed. we found that in the absence of a functional replicase, assembled virions cont ... | 2005 | 15936794 |
| a functional histidine-tagged replication initiator protein: implications for the study of single-stranded dna virus replication in planta. | replication initiation of nanoviruses, plant viruses with a multipartite circular single-stranded dna genome, is triggered by the master rep (m-rep) protein. to enable the study of interactions between m-rep and viral or host factors involved in replication, we designed oligohistidine-tagged variants of the nanovirus faba bean necrotic yellows virus (fbnyv) m-rep protein that allow affinity purification of enzymatically active m-rep from plant tissue. the tagged m-rep protein was able to initiat ... | 2005 | 15956586 |
| stachytarpheta leaf curl virus is a novel monopartite begomovirus species. | begomovirus isolates were obtained from stachytarpheta jamaicensis plants showing leaf curl and chlorosis symptoms collected in the hainan province of china. the complete sequences of isolates hn5-4, hn6-1, hn30 and hn34 were determined to be 2748, 2751, 2748 and 2748 nucleotides long, respectively. the complete sequences of the four isolates share more than 94.9% nucleotide sequence identity, but all of them have less than 86% nucleotide sequence identity with other reported begomoviruses. the ... | 2005 | 15986176 |
| heat shock protein 90 and its co-chaperone protein phosphatase 5 interact with distinct regions of the tomato i-2 disease resistance protein. | recent data suggest that plant disease resistance (r) proteins are present in multi-protein complexes. tomato r protein i-2 confers resistance against the fungal pathogen fusarium oxysporum. to identify components of the i-2 complex, we performed yeast two-hybrid screens using the i-2 leucine-rich repeat (lrr) domain as bait, and identified protein phosphatase 5 (pp5) as an i-2 interactor. subsequent screens revealed two members of the cytosolic heat shock protein 90 (hsp90) family as interactor ... | 2005 | 15998314 |
| [the analysis of rbcs gene function by post-transcription gene silencing in nicotiana benthamiana]. | a system of virus-induced post-transcriptional gene silencing for studying rbcs gene function was established and optimized using tobacco rattle virus vector and nicotiana benthamiana as experimental materiaes. the following analyses were conducted: phenotypic characterization of rbcs gene silenced plants, transcription levels of rbcs gene by rt-pcr; protein levels of rbcs by the antibodies of rbcs and rbcl and photosynthetic pigments wntents in rbcs silenced plants by hplc method. the results s ... | 2005 | 16018185 |
| evidence implying only unprimed rdrp activity during transitive gene silencing in plants. | rna silencing is a sequence-specific rna degradation mechanism found in most eukaryotes, where small cleavage products (sirnas) of double stranded rna (dsrna) mediate silencing of genes with sequence identity to the dsrna inducer. in several systems, silencing has been found to spread from the dsrna inducer sequence into upstream or downstream regions of the target rna, a phenomenon termed transitive silencing. in nematodes, silencing spreads only in the 3'-5' direction along the target mrna by ... | 2005 | 16021340 |
| immunomodulation of cucumber mosaic virus infection by intrabodies selected in vitro from a stable single-framework phage display library. | immunomodulation by the ectopic expression of intracellular antibodies ('intrabodies') has a great potential for interfering with physiological or pathological functions in vivo in a highly specific manner. one of the major obstacles of this technology is the inability of most antibodies to properly fold and function in the reducing environment of the cytoplasm, which prevents the formation of essential disulfide bonds. we wished to assess the intracellular performance of antibodies derived from ... | 2005 | 16021397 |
| ethylene-mediated cross-talk between calcium-dependent protein kinase and mapk signaling controls stress responses in plants. | plants are constantly exposed to environmental changes and need to integrate multiple external stress cues. calcium-dependent protein kinases (cdpks) are implicated as major primary ca2+ sensors in plants. cdpk activation, like activation of mitogen-activated protein kinases (mapks), is triggered by biotic and abiotic stresses, although distinct stimulus-specific stress responses are induced. to investigate whether cdpks are part of an underlying mechanism to guarantee response specificity, we i ... | 2005 | 16027369 |
| an rna-dependent rna polymerase prevents meristem invasion by potato virus x and is required for the activity but not the production of a systemic silencing signal. | one of the functions of rna silencing in plants is antiviral defense. a hallmark of rna silencing is spreading of the silenced state through the plant. little is known about the nature of the systemic silencing signal and the proteins required for its production, transport, and reception in plant tissues. here, we show that the rna-dependent rna polymerase rdr6 in nicotiana benthamiana is involved in defense against potato virus x at the level of systemic spreading and in exclusion of the virus ... | 2005 | 16040651 |
| a begomovirus dnabeta-encoded protein binds dna, functions as a suppressor of rna silencing, and targets the cell nucleus. | our previous results demonstrated that the dnabeta satellite (y10beta) associated with tomato yellow leaf curl china virus y10 isolate (tylccnv-y10) is essential for induction of leaf curl symptoms in plants and that transgenic expression of its betac1 gene in nicotiana plants induces virus-like symptoms. in the present study, in vitro dna binding activity of the betac1 proteins of y10beta and dnabeta (y35beta) found in the tobacco curly shoot virus y35 isolate (tbcsv-y35) were studied following ... | 2005 | 16051868 |
| occurrence of cucumber mosaic virus on vanilla (vanilla planifolia andrews) in india. | cucumber mosaic virus (cmv) causing mosaic, leaf distortion and stunting of vanilla (vanilla planifolia andrews) in india was characterized on the basis of biological and coat protein (cp) nucleotide sequence properties. in mechanical inoculation tests, the virus was found to infect members of chenopodiaceae, cucurbitaceae, fabaceae and solanaceae. nicotiana benthamiana was found to be a suitable host for the propagation of cmv. the virus was purified from inoculated n. benthamiana plants and ne ... | 2005 | 16052072 |
| a bipartite tobacco mosaic virus-defective rna (drna) system to study the role of the n-terminal methyl transferase domain in cell-to-cell movement of drnas. | plant viruses, in particular tobacco mosaic virus (tmv), are model systems to study rna and protein trafficking in plants. although tmv cell-to-cell transport controlled by the 30-kda movement protein (mp) has been intensively studied, it was only recently demonstrated that the 126/183-kda replicase proteins are also involved in cell-to-cell movement. elucidating the role(s) of 126/183-kda proteins in movement is complicated because these proteins have multiple functions associated with replicat ... | 2005 | 16081123 |
| identification of regions of the beet mild curly top virus (family geminiviridae) capsid protein involved in systemic infection, virion formation and leafhopper transmission. | plant viruses in the genus curtovirus (family geminiviridae) are vectored by the beet leafhopper (circulifer tenellus) and cause curly top disease in a wide range of dicotyledonous plants. an infectious clone of an isolate of beet mild curly top virus (bmctv-[w4]), associated with an outbreak of curly top in pepper and tomato crops, was characterized and used to investigate the role of the capsid protein (cp) in viral biology and pathogenesis. frameshift mutations were introduced into the overla ... | 2005 | 16085227 |
| characterization of resistance in transgenic nicotiana benthamiana encoding n-terminal deletion and assembly mutants of the tobacco etch potyvirus coat protein. | the resistance of transgenic nicotiana benthamiana plants encoding wild type, truncated and point mutants of the tobacco etch virus (tev) coat protein (cp) was analyzed. after r1 plants from 45 transgenic lines were challenged with tev, six percent of the lines exhibited high resistance, 38% exhibited low resistance, and the remainder were susceptible. the phenomenon of recovery and delay in symptom development was observed in 65% and 56% of the resistant and susceptible lines, respectively. pla ... | 2005 | 16086100 |
| high-throughput in planta expression screening identifies a class ii ethylene-responsive element binding factor-like protein that regulates plant cell death and non-host resistance. | we performed high-throughput screening using the potato virus x (pvx) system to overexpress nicotiana benthamiana genes in planta and identify positive regulators of cell death. this screening identified nbcd1, a novel class ii ethylene-responsive element binding factor (erf), as a potent inducer of the hypersensitive response (hr)-like cell death. nbcd1 expression was induced by treatments with inf1 elicitor and a non-host pathogen pseudomonas cichorii. nbcd1 exhibited transcriptional repressor ... | 2005 | 16098104 |
| specific and common changes in nicotiana benthamiana gene expression in response to infection by enveloped viruses. | microarrays derived from solanum tuberosum expressed sequence tags were used to test the hypothesis that genetically distinct enveloped viruses elicit unique changes in nicotiana benthamiana gene expression. the results of our study, which included sonchus yellow net virus (synv), a plant rhabdovirus that replicates in the nucleus of infected cells, and impatiens necrotic spot virus (insv), a plant bunyavirus that replicates in the cytoplasm, were consistent with this hypothesis. statistically s ... | 2005 | 16099921 |
| the tubule-forming nsm protein from tomato spotted wilt virus complements cell-to-cell and long-distance movement of tobacco mosaic virus hybrids. | a florida isolate of tomato spotted wilt virus (tswv) was able to complement cell-to-cell movement of a movement-defective tobacco mosaic virus (tmv) vector expressing the jellyfish green fluorescent protein (gfp). to test for complementation of movement in the absence of other tswv proteins, the open reading frame for the nsm protein was expressed from tmv constructs encoding only the tmv replicase proteins. nsm was expressed from either the coat protein or movement protein subgenomic promoter, ... | 2005 | 16112159 |
| functional expression of an ajmaline pathway-specific esterase from rauvolfia in a novel plant-virus expression system. | acetylajmalan esterase (aae) plays an essential role in the late stage of ajmaline biosynthesis. based on the partial peptide sequences of aae isolated and purified from rauvolfia cell suspensions, a full-length aae cdna clone was isolated. the amino acid sequence of aae has the highest level of identity of 40% to putative lipases known from the arabidopsis thaliana genome project. based on the primary structure aae is a new member of the gdsl lipase superfamily. the expression in escherichia co ... | 2005 | 16133216 |
| integrity of nonviral fragments in recombinant tomato bushy stunt virus and defective interfering rna is influenced by silencing and the type of inserts. | recombinant plant viruses have the propensity to remove foreign inserts during replication. this process is virus-specific and occurs in a host-dependent manner. in the present study, we investigated the integrity of foreign inserts in recombinant plant viruses using a model system consisting of tomato bushy stunt virus (tbsv) and its defective interfering rna (di). these were tested in nicotiana benthamiana plants that were either wild type or transgenic for the green fluorescent protein (gfp) ... | 2005 | 16134892 |