Publications

the arabidopsis atste24 is a caax protease with broad substrate specificity.	following prenylation, the proteins are subject to two prenyl-dependent modifications at their c-terminal end, which are required for their subcellular targeting. first, the three c-terminal residues of the caax box prenylation signaling motif are removed, which is followed by methylation of the free carboxyl group of the prenyl cysteine moiety. an arabidopsis homologue of the yeast caax protease ste24 (afc1) was cloned and expressed in rce1 delta ste24 delta mutant yeast to demonstrate function ...	2002	12039957
p0 of beet western yellows virus is a suppressor of posttranscriptional gene silencing.	higher plants employ a homology-dependent rna-degradation system known as posttranscriptional gene silencing (ptgs) as a defense against virus infection. several plant viruses are known to encode proteins that can suppress ptgs. here we show that p0 of beet western yellows virus (bwyv) displays strong silencing suppressor activity in a transient expression assay based upon its ability to inhibit ptgs of green fluorescent protein (gfp) when expressed in agro-infiltrated leaves of nicotiana bentha ...	2002	12050394
subcellular localisation, protein interactions, and rna binding of potato mop-top virus triple gene block proteins.	subcellular localisation, protein interactions, and rna binding of the triple gene block proteins (tgbp) of potato mop-top virus (pmtv) were studied. the 13-kda (tgbp2) and 21-kda (tgbp3) proteins with or without green fluorescent protein fused to their n-terminus, and the 51-kda protein (tgbp1) were expressed individually from a recombinant tobacco mosaic virus (tmv) vector. fluorescent images and western immunoblotting experiments of recombinant tmv-infected nicotiana benthamiana cells suggest ...	2002	12093178
a novel class of large and infectious defective rnas of citrus tristeza virus.	citrus tristeza virus (ctv)-infected plants contain one or more populations of defective rnas (drnas), mostly with a size range of ca. 2.0 to 5.0 kb. several ctv drnas have been characterized and found to consist mainly of the two termini of the genomic rna, with extensive internal deletions. the present paper describes a new class of large ( approximately 12.0 kb) drnas from three different ctv isolates with two unusual features. first is their composition with intact replicase genes. these drn ...	2002	12093181
plant-derived human papillomavirus 16 e7 oncoprotein induces immune response and specific tumor protection.	vaccine strategies for treatment of human papillomavirus-induced cervical cancer are based on either the recombinant e7 fusion oncoprotein or e7 ctl peptides. the therapeutic potential of the e7-based vaccine depends on the use of different adjuvants. in this study, we describe for the first time the expression of the human papillomavirus 16 e7 protein in nicotiana benthamiana plant using a potato virus x-derived vector. c57bl/6 mice immunized with e7-containing crude foliar extracts developed b ...	2002	12097270
inhibition of tobacco mosaic virus replication in lateral roots is dependent on an activated meristem-derived signal.	viral invasion of the root system of nicotiana benthamiana was studied noninvasively with a tobacco mosaic virus (tmv) vector expressing the green-fluorescent protein (gfp). lateral root primordia, which developed from the pericycle of primary roots, became heavily infected as they emerged from the root cortex. however, following emergence, a progressive wave of viral inhibition occurred that originated in the lateral-root meristem and progressed towards its base. excision of source and sink tis ...	2002	12099219
role of scf ubiquitin-ligase and the cop9 signalosome in the n gene-mediated resistance response to tobacco mosaic virus.	the tobacco n gene confers resistance to tobacco mosaic virus (tmv) and encodes a toll-interleukin-1 receptor/nucleotide binding/leu-rich repeat class protein. recent evidence indicates that the nicotiana benthamiana rar1 gene (nbrar1), which encodes a protein with a zinc finger motif called chord (cys- and his-rich domain), is required for the function of n. to investigate the role of nbrar1 in plant defense, we identified its interaction partners. we show that the nbrar1 protein interacts with ...	2002	12119369
ubiquitin ligase-associated protein sgt1 is required for host and nonhost disease resistance in plants.	homologues of the yeast ubiquitin ligase-associated protein sgt1 are required for disease resistance in plants mediated by nucleotide-binding site/leucine-rich repeat (nbs-lrr) proteins. here, by silencing sgt1 in nicotiana benthamiana, we extend these findings and demonstrate that sgt1 has an unexpectedly general role in disease resistance. it is required for resistance responses mediated by nbs-lrr and other r proteins in which pathogen-derived elicitors are recognized either inside or outside ...	2002	12119413
cloning and expression of squalene synthase cdna from hot pepper (capsicum annuum l.).	we isolated and artificially expressed a cdna clone of the capsicum annuum squalene synthase (cass) gene to elucidate the pattern of alternatively regulated two-branch point enzymes. the 1,674-bp cass cdna contained an open reading frame of 411 amino acids, yielding a predicted molecular mass of about 45 kda. a deduced amino acid sequence comparison to other squalene syntheses showed identities with nicotiana tabacum (91%), nicotiana benthamiana (90%), arabidopsis thaliana (79%), and rats (40%). ...	2002	12132584
expression in plants and immunogenicity of plant virus-based experimental rabies vaccine.	a new approach to the production and delivery of vaccine antigens is the use of engineered amino virus-based vectors. a chimeric peptide containing antigenic determinants from rabies virus glycoprotein (g protein) (amino acids 253-275) and nucleoprotein (n protein) (amino acids 404-418) was pcr-amplified and cloned as a translational fusion product with the alfalfa mosaic virus (almv) coat protein (cp). this recombinant cp was expressed in two plant virus-based expression systems. the first one ...	2002	12163267
a geminivirus replication protein interacts with a protein kinase and a motor protein that display different expression patterns during plant development and infection.	the geminivirus protein al1 initiates viral dna replication, regulates its own expression, and induces plant gene transcription. to better understand how al1 interacts with host proteins during these processes, we used yeast two-hybrid library screening and a baculovirus protein interaction system to identify plant proteins that interact with al1. these studies identified a ser/thr kinase, a kinesin, and histone h3 as al1 partners. the kinase is autophosphorylated and can phosphorylate common ki ...	2002	12172024
suppression of a key gene involved in chlorophyll biosynthesis by means of virus-inducing gene silencing.	the chlh gene coding the h subunit of magnesium chelatase, an enzyme involved in chlorophyll biosynthesis, was silenced in nicotiana benthamiana plants by infection with tobacco mosaic virus vectors (ptmv-30b) containing 67,214 or 549 nt long chlh inserts. silencing of the nuclear chlh gene induced a chimeric phenotype with green and yellow/white leaves associated with alterations of chloroplast shape and ultrastructure. the symptoms became first evident around veins of young leaves, and only la ...	2002	12175014
the golgi localization of arabidopsis thaliana beta1,2-xylosyltransferase in plant cells is dependent on its cytoplasmic and transmembrane sequences.	to investigate the targeting of proteins to the plant golgi we studied arabidopsis thaliana beta1,2-xylosyltransferase (xylt), a glycosyltransferase which is unique to plants and some invertebrates. different deletion constructs of the putative cytoplasmic (c)-transmembrane (t)-stem (s) region of the enzyme were transiently expressed in the tobacco-related model plant species nicotiana benthamiana. subcellular localization of fusion proteins between cts, ct, t, or c domains and the reporter mole ...	2002	12175019
sequence-, tissue-, and delivery-specific targeting of rna during post-transcriptional gene silencing.	transgenic nicotiana benthamiana plants expressing an untranslatable version of the coat protein (cp) gene from the tamarillo mosaic virus (tamv) were either resistant to tamv infection or recovered from infection. these phenotypes were the result of a post-transcriptional gene silencing (ptgs) mechanism that targeted tamv-cp sequences for degradation. the tamv-cp sequences were degraded when present in the wild-type tamv potyvirus, in transgene mrna, or in chimeric viral vectors based on white ...	2002	12182332
virus-induced gene silencing in transgenic plants expressing the minor capsid protein of beet western yellows virus.	transgenic nicotiana benthamiana expressing the minor coat protein p74 of the phloem-limited beet western yellows virus (bwyv) exhibited an unusual spatial pattern of post-transcriptional gene silencing (ptgs) when infected with bwyv or related viruses. following infection, transgenic p74 and its mrna accumulated to only low levels, 21 to 23 nucleotide rnas homologous to the transgene appeared, and the transgene dna underwent methylation. the infecting viral rna, however, was not subject to sign ...	2002	12182337
silencing of a viral rna silencing suppressor in transgenic plants.	high expression levels of the helper component proteinase (hc(pro)), a known virus suppressor of rna silencing, were attained in nicotiana benthamiana transformed with the hc(pro) cistron of potato virus a (pva, genus potyvirus). no spontaneous silencing of the hc(pro) transgene was observed, in contrast to the pva coat protein (cp)-encoding transgene in other transgenic lines. hc(pro)-transgenic plants were initially susceptible to pva and were systemically infected by 14 days post-inoculation ...	2002	12185289
transgenic plants expressing hc-pro show enhanced virus sensitivity while silencing of the transgene results in resistance.	nicotiana benthamiana plants were engineered to express sequences of the helper component-proteinase (hc-pro) of cowpea aphid-borne mosaic potyvirus (cabmv). the sensitivity of the transgenic plants to infection with parental and heterologous viruses was studied. the lines expressing hc-pro showed enhanced symptoms after infection with the parental cabmv isolate and also after infection with a heterologous potyvirus, potato virus y (pvy) and a comovirus, cowpea mosaic virus (cpmv). on the other ...	2002	12206307
specific degradation of 3' regions of gus mrna in posttranscriptionally silenced tobacco lines may be related to 5'-3' spreading of silencing.	target regions for posttranscriptional silencing of transgenes often reside in the 3' region of the coding sequence, although there are exceptions. to resolve if the target region is determined by the gene undergoing silencing rather than by the structure of the transgene loci or the plant genetic background, we have performed detailed analyses of target regions in three spontaneously beta-glucuronidase (gus) silencing tobacco lines of different origin. from quantitative cosuppression experiment ...	2002	12212847
virus-induced gene silencing in tomato.	we have previously demonstrated that a tobacco rattle virus (trv)-based vector can be used in virus-induced gene silencing (vigs) to study gene function in nicotiana benthamiana. here we show that recombinant trv infects tomato plants and induces efficient gene silencing. using this system, we suppressed the pds, ctr1 and ctr2 genes in tomato. suppression of ctr1 led to a constitutive ethylene response phenotype and up-regulation of an ethylene response gene, chitinase b. this phenotype is simil ...	2002	12220268
movement of potato spindle tuber viroid reveals regulatory points of phloem-mediated rna traffic.	increasing evidence indicates that the phloem mediates traffic of selective rnas within a plant. how an rna enters, moves in, and exits the phloem is poorly understood. potato spindle tuber viroid (pstvd) is a pathogenic rna that does not encode proteins and is not encapsidated, and yet it replicates autonomously and traffics systemically within an infected plant. the viroid rna genome must interact directly with cellular factors to accomplish these functions and is, therefore, an excellent prob ...	2002	12226494
phloem unloading in sink leaves of nicotiana benthamiana: comparison of a fluorescent solute with a fluorescent virus.	using noninvasive imaging techniques, we compared phloem unloading of the membrane-impermeant, fluorescent solute carboxyfluorescein (cf) with that of potato virus x expressing the gene for the green fluorescent protein. although systemic virus transport took considerably longer to occur than did cf transport, unloading of both solute and virus occurred predominantly from the class iii vein network, a highly branched veinal system found between class ii veins. the minor veins (classes iv and v) ...	1997	12237387
rna-mediated virus resistance: role of repeated transgenes and delineation of targeted regions.	resistance to cowpea mosaic virus (cpmv) in transgenic nicotiana benthamiana plants is rna mediated. in resistant cpmv movement protein (mp) gene-transformed lines, transgene steady state mrna levels were low, whereas nuclear transcription rates were high, implying that a post-transcriptional gene-silencing mechanism is at the base of the resistance. the silencing mechanism can also affect potato virus x (pvx) rnas when they contain cpmv mp gene sequences. in particular, sequences situated in th ...	1996	12239378
agroinfection as a rapid method for propagating cowpea mosaic virus-based constructs.	to increase the efficiency of infections with cowpea mosaic virus (cpmv)-based constructs, clones suitable for agroinfection were constructed. full-length copies of rna-1 and rna-2 were inserted between the sequence of a cauliflower mosaic virus (camv) 35s promoter and a nos terminator and were introduced into the agrobacterium tumefaciens plasmid, pbinplus. infiltration of leaves of either nicotiana benthamiana or cowpea (vigna unguiculata) with a bacterial suspension containing a mixture of th ...	2002	12270666
role of the alfalfa mosaic virus methyltransferase-like domain in negative-strand rna synthesis.	rnas 1 and 2 of the tripartite genome of alfalfa mosaic virus (amv) encode the replicase proteins p1 and p2, respectively. p1 contains a methyltransferase-like domain in its n-terminal half, which has a putative role in capping the viral rnas. six residues in this domain that are highly conserved in the methyltransferase domains of alphavirus-like viruses were mutated individually in amv p1. none of the mutants was infectious to plants. mutant rna 1 was coexpressed with wild-type (wt) rnas 2 and ...	2002	12388692
the production of a genus-specific recombinant antibody (scfv) using a recombinant potyvirus protease.	a single chain variable fragment antibody (scfv; anti-nia scfv102) was selected from a synthetic human antibody library by using a nia protease of plum pox virus (ppv) as an antigen, which was expressed in bacteria. the nia protease forms the nuclear inclusion body a and acts as the major protease in the cleavage of the viral polyprotein into functional proteins. the nia protein was detected with anti-nia scfv102 after expression in escherichia coli cells as well as from ppv-infected nicotiana b ...	2002	12393153
expression of a phytophthora sojae necrosis-inducing protein occurs during transition from biotrophy to necrotrophy.	phytophthora sojae is an oomycete that causes stem and root rot on soybean plants. to discover pathogen factors that produce disease symptoms or activate plant defense responses, we identified putative secretory proteins from expressed sequence tags (ests) and tested selected candidates using a heterologous expression assay. from an analysis of 3035 ests originating from mycelium, zoospore, and infected soybean tissues, we identified 176 putative secreted proteins. a total of 16 different cdnas ...	2002	12410814
subcellular location of the helper component-proteinase of cowpea aphid-borne mosaic virus.	the helper component-proteinase (hc-pro) of cowpea aphid-borne mosaic virus (cabmv) was expressed in escherichia coli and used to obtain hc-pro antiserum that was used as an analytical tool for hc-pro studies. the antiserum was used in immunofluorescence assays to study the subcellular location of hc-pro expressed with other viral proteins in cowpea protoplasts in a natural cabmv infection, or in protoplasts transfected with a transient expression construct expressing hc-pro separately from othe ...	2002	12416684
host-dependent requirement for the potato leafroll virus 17-kda protein in virus movement.	the requirement for the 17-kda protein (p17) of potato leafroll virus (plrv) in virus movement was investigated in four plant species: potato (solanum tuberosum), physalis floridana, nicotiana benthamiana, and n. clevelandii. two plrv p17 mutants were characterized, one that does not translate the p17 and another that expresses a p17 missing the first four amino acids. the p17 mutants were able to replicate and accumulate in agroinoculated leaves of potato and p. floridana, but they were unable ...	2002	12437307
long-distance movement, virulence, and rna silencing suppression controlled by a single protein in hordei- and potyviruses: complementary functions between virus families.	rna silencing is a natural defense mechanism against genetic stress factors, including viruses. a mutant hordeivirus (barley stripe mosaic virus [bsmv]) lacking the gammab gene was confined to inoculated leaves in nicotiana benthamiana, but systemic infection was observed in transgenic n. benthamiana expressing the potyviral silencing suppressor protein hcpro, suggesting that the gammab protein may be a long-distance movement factor and have antisilencing activity. this was shown for gammab prot ...	2002	12438624
replication of potato spindle tuber viroid in cultured cells of tobacco and nicotiana benthamiana: the role of specific nucleotides in determining replication levels for host adaptation.	we have developed an electroporation protocol to inoculate cultured cells of tobacco and nicotiana benthamiana with in vitro transcripts of potato spindle tuber viroid (pstvd) to characterize viroid structural features that determine replication efficiency at the cellular level. both (+)- and (-)-strands of pstvd were detected by northern blots as early as 6 h postinoculation (h.p.i.). accumulation of the (+)-circular pstvd increased very rapidly starting at 24 h.p.i. and continued beyond 6 days ...	2002	12441088
virus-induced silencing of ftsh gene in nicotiana benthmiana causes a striking bleached leaf phenotype.	a recombinant potato virus x (pvx) vector, ptxs.ftsh, harboring partial sequence of ftsh gene of nicotiana benthamiana was constructed to silence the expression of endogenous ftsh homologous gene in n. benthamiana. inoculation with in vitro runoff transcript of ptxs.ftsh to n. benthamiana plants allowed silencing of ftsh, causing striking bleaching of upper leaves reminiscent of var2 mutant phenotype of arabidopsis thaliana. ftsh-silenced plants exhibited no resistance against tobacco mosaic vir ...	2002	12441644
host dna replication is induced by geminivirus infection of differentiated plant cells.	the geminivirus tomato golden mosaic virus (tgmv) replicates in differentiated plant cells using host dna synthesis machinery. we used 5-bromo-2-deoxyuridine (brdu) incorporation to examine dna synthesis directly in infected nicotiana benthamiana plants to determine if viral reprogramming of host replication controls had an impact on host dna replication. immunoblot analysis revealed that up to 17-fold more brdu was incorporated into chromosomal dna of tgmv-infected versus mock-infected, similar ...	2002	12468723
two e2f elements regulate the proliferating cell nuclear antigen promoter differently during leaf development.	e2f transcription factors regulate genes expressed at the g1/s boundary of the cell division cycle in higher eukaryotes. although animal e2f proteins and their target promoters have been studied extensively, little is known about how these factors regulate plant promoters. an earlier study identified two e2f consensus binding sites in the promoter of a nicotiana benthamiana gene encoding proliferating cell nuclear antigen (pcna) and showed that the proximal element (e2f2) is required for the ful ...	2002	12468739
subcellular targeting domains of abutilon mosaic geminivirus movement protein bc1.	abutilon mosaic geminivirus (abmv) encodes two movement proteins, bv1 and bc1, which mediate the intra- and intercellular transport of viral dna in plants cooperatively. it has been shown previously that singly expressed bc1, fused to green fluorescent protein (gfp), accumulates preferentially either at the cell periphery or around the nucleus in separate plant cells. to define the bc1 domains responsible for understanding the subcellular sorting, deletion mutants were fused to gfp and expressed ...	2002	12491102
negative-strand tospoviruses and tenuiviruses carry a gene for a suppressor of gene silencing at analogous genomic positions.	posttranscriptional silencing of a green fluorescent protein (gfp) transgene in nicotiana benthamiana plants was suppressed when these plants were infected with tomato spotted wilt virus (tswv), a plant-infecting member of the bunyaviridae: infection with tswv resulted in complete reactivation of gfp expression, similar to the case for potato virus y, but distinct from that for cucumber mosaic virus, two viruses known to carry genes encoding silencing suppressor proteins. agrobacterium-based lea ...	2003	12502849
the importance of alfalfa mosaic virus coat protein dimers in the initiation of replication.	deletion and substitution mutations affecting the oligomerization of alfalfa mosaic virus (amv) coat protein (cp) were studied in protoplasts to determine their effect on genome activation, an early step in amv replication. the cp mutants that formed dimers, cpdeltac9 and cpc-a(r)f, were highly active in initiating replication with 63-84% of wild-type (wt) cp activity. however, all mutants that did not form dimers, cpdeltac18, cpdeltac19, cpc-wfp, and cpc-w, were much less active with 19-33% of ...	2003	12504539
host-dependent recombination of a tomato bushy stunt virus coat protein mutant yields truncated capsid subunits that form virus-like complexes which benefit systemic spread.	this study examined the contribution of the tomato bushy stunt virus (tbsv) coat protein (cp) and its corresponding rna to systemic infection of plants. compared to results obtained with a mutant lacking the 5'-half of the cp gene, the presence of those cp-rna sequences in another mutant benefited tbsv infection on nicotiana benthamiana even though wild-type cp expression was eliminated by introduction of a small out-of-frame deletion. rt-pcr of viral rna associated with rapid infections establi ...	2002	12504582
generation and characterisation of functional recombinant antibody fragments against rna replicase nib from plum pox virus.	a monoclonal antibody (mab 2a) able to react against the rna replicase nib from plum pox virus (ppv) was obtained and used for generating a specific scfv fragment. the vh and vl coding sequences were cloned and expressed as a fusion scfv protein to alkaline phosphatase. this fusion protein was able to recognise viral nib in both western and tissue-print elisa blots. the affinity and specificity of scfv2a for nib was similar to that of the parental mab and the region yleafy from ppv-nib was ident ...	2003	12535657
molecular analysis of the cucumber leaf spot virus genome.	full-length clones of the genome of the aureusvirus, cucumber leaf spot virus (clsv), have been constructed and infectious t7 polymerase derived synthetic transcripts have been produced. mutational analysis of the genome indicates a role for p84 in viral rna replication, the cp in systemic movement, p27 in viral cell-to-cell movement and p17 in symptom induction. a clsv mutant lacking orfs for the cp, p27 and p17 (clsv yx) was capable of replication and systemic movement in transgenic nicotiana ...	2003	12573495
identification of a minimal sequence required for activation of the tomato golden mosaic virus coat protein promoter in protoplasts.	transient expression studies using a nicotiana benthamiana suspension cell-derived protoplast system have identified a minimal sequence that is necessary and sufficient for activation of the tomato golden mosaic virus coat protein (cp) promoter by the viral trap protein (also called al2). the sequence has a bipartite arrangement in which elements located between -125 to -107 and -96 to -60 from the transcription start site are both required for trap-mediated activation. one of the sequences (-96 ...	2003	12573590
dynamics of the vigs-mediated chimeric silencing of the nicotiana benthamiana chlh gene and of the tobacco mosaic virus vector.	the chlh gene, encoding for the h subunit of the magnesium chelatase enzyme, was silenced in nicotiana bentahamiana plants by virus-induced gene silencing (vigs), using tobacco mosaic virus (tmv) expression vector. strong silencing of the chlh target gene was initiated only in the apical tissues, in which the endogenous transcription level of the target gene and the level of tmv vector rna were both very high. the virus vector was also targeted by vigs, and its suppression was correlated with th ...	2003	12575743
agrosuppression: a bioassay for the hypersensitive response suited to high-throughput screening.	we describe a novel method, agrosuppression, that addresses the need for an assay of the hypersensitive response (hr) in intact plants that is rapid and adapted to high-throughput functional screening of plant and pathogen genes. the agrosuppression assay is based on inoculation of intact plants with a mixture of agrobacterium tumefaciens strains carrying (i) a binary plasmid with one or more candidate hr-inducing genes and (ii) a tumor-inducing (oncogenic) t-dna. in the absence of hr induction, ...	2003	12580277
a naturally occurring recombinant dna-a of a typical bipartite begomovirus does not require the cognate dna-b to infect nicotiana benthamiana systemically.	species of the genus begomovirus (family geminiviridae) found in the western hemisphere typically have a bipartite genome that consists of two 2.6 kb dna genomic components, dna-a and dna-b. we have identified and cloned genomic components of a new tomato-infecting begomovirus from brazil, for which the name tomato crinkle leaf yellows virus (tcrlyv) is proposed, and a dna-a variant of tomato chlorotic mottle virus (tocmv-[mg-bt1]). sequence analysis revealed that tcrlyv was most closely related ...	2003	12604824
use of green fluorescent protein to quantify the growth of colletotrichum during infection of tobacco.	to develop a quantitative assay of fungal growth inside plant tissues, strains of colletotrichum destructivum and colletotrichum orbiculare were transformed with a modified green fluorescent protein (gfp) gene fused with a glyceraldehyde-3-phosphate dehydrogenase promoter from aspergillus nidulans. transformants expressed gfp in culture and had the same growth rate and general appearance as the wild type. gfp was observed in all fungal structures during infection of leaves of nicotiana benthamia ...	2003	12609730
nicotiana benthamiana gp91phox homologs nbrboha and nbrbohb participate in h2o2 accumulation and resistance to phytophthora infestans.	active oxygen species (aos) are responsible for triggering defense responses in plants. respiratory burst oxidase homologs (rboh genes) have been implicated in aos generation. we have isolated two rboh cdnas, nbrboha and nbrbohb, from nicotiana benthamiana leaves. nbrboha was expressed constitutively at a low level and the transcripts were increased after mechanical stress of control leaf infiltration, whereas nbrbohb was induced specifically by the protein elicitor inf1 from the potato pathogen ...	2003	12615943
turnip crinkle virus coat protein mediates suppression of rna silencing in nicotiana benthamiana.	all of the protein products of turnip crinkle virus (tcv; tombusviridae, carmovirus) were tested for their ability to suppress rna silencing of a reporter gene after transient expression in agrobacterium-infiltrated nicotiana benthamiana leaves. only the capsid protein, p38, showed suppression activity, although this was not obvious when p38 was expressed as part of a tcv infection of the same tissues. when p38 was expressed from a pvx vector, symptoms with enhanced severity that correlated with ...	2003	12620795
immunodetection and fluorescent microscopy of transgenically expressed hordeivirus tgbp3 movement protein reveals its association with endoplasmic reticulum elements in close proximity to plasmodesmata.	the subcellular localization of the hydrophobic tgbp3 protein of poa semilatent virus (pslv, genus hordeivirus) was studied in transgenic plants using fluorescent microscopy to detect green fluorescent protein (gfp)-tagged protein and immunodetection with monoclonal antibodies (mabs) raised against the gfp-based fusion expressed in e. coli. in western blot analysis, mabs efficiently recognized the wild-type and gfp-fused pslv tgbp3 proteins expressed in transgenic nicotiana benthamiana, but fail ...	2003	12655101
potato mop-top virus: the coat protein-encoding rna and the gene for cysteine-rich protein are dispensable for systemic virus movement in nicotiana benthamiana.	full-length genomic cdna clones of the swedish isolate of potato mop-top virus (pmtv) were transcribed in vitro using t7 rna polymerase. the combination of rna 1, 2 and 3 synthesized in the presence of m(7)gpppg cap analogue was infectious when inoculated onto nicotiana benthamiana plants. also, the combination of rna 1 (encodes the viral replicase) with rna 3 [encodes the triple gene block proteins and a small cysteine-rich protein (crp)] was infectious and both rnas moved systemically in n. be ...	2003	12655103
molecular characterization of nbpaf encoding the alpha6 subunit of the 20s proteasome in nicotiana benthamiana.	the 26s proteasome involved in degradation of proteins covalently modified with polyubiquitin consists of the 20s proteasome and 19s regulatory complex. the nbpaf gene encoding the alpha6 subunit of the 20s proteasome was identified from nicotiana benthamiana. nbpaf exhibits high sequence homology with the corresponding genes from arabidopsis, human and yeast. the deduced amino acid sequence of nbpaf reveals that this protein contains the proteasome alpha-type subunits signature and nuclear loca ...	2003	12661772
c-terminal domain of a hevein-like protein from wasabia japonica has potent antimicrobial activity.	an antimicrobial protein, designated wjamp-1, was purified from leaves of wasabia japonica l. wjamp-1 showed antimicrobial activity against both fungi and bacteria. the deduced amino acid sequence of cdna of wjamp-1 showed 60% and 70% identity with a hevein from hevea brasiliansis and a hevein-like protein from arabidopsis thaliana, respectively. however, matured wjamp-1 lacked the hevein domain and may correspond to the c-terminal domain of hevein. southern blot analysis showed that one or two ...	2003	12668776
geminivirus al2 and l2 proteins interact with and inactivate snf1 kinase.	geminivirus al2 and l2 proteins cause enhanced susceptibility, characterized primarily by an increase in viral infectivity, when expressed in transgenic plants. here, we present genetic and biochemical evidence that enhanced susceptibility is attributable to the interaction of al2 and l2 with snf1 kinase, a global regulator of metabolism. specifically, we show that al2 and l2 inactivate snf1 in vitro and in vivo. we further demonstrate that expression of an antisense snf1 transgene in nicotiana ...	2003	12671096
peptide-mediated broad-spectrum plant resistance to tospoviruses.	plant viruses have a significant impact on agronomic losses worldwide. a new strategy for engineering virus-resistant plants by transgenic expression of a dominant interfering peptide is presented here. this peptide of 29 aa strongly interacts with the nucleocapsid proteins (n) of different tospoviruses. transgenic nicotiana benthamiana lines expressing the peptide fused to a carrier protein were challenged with five different tospoviruses that have a nucleocapsid protein interacting with the pe ...	2003	12682295
different elongation pathways in the biosynthesis of acyl groups of trichome exudate sugar esters from various solanaceous plants.	two common pathways are known for elongation of aliphatic acids via acetate in biological organisms: the fatty acid synthase (fas) and the alpha-ketoacid elongation (alphakae) pathways. the alphakae route is utilized in many biosynthetic pathways, including the tricarboxylic acid cycle, leucine biosynthesis, and in formation of coenzyme b, glucosinolates, alpha-ketoadipate, sugar-ester acyl acids, short-chain alcohols of yeast and clostridium species, 2-amino-4-methylhex-4-enoic acid, and l-gamm ...	2003	12687369
a chemical-regulated inducible rnai system in plants.	constitutive expression of an intron-containing self-complementary 'hairpin' rna (ihprna) has recently been shown to efficiently silence target genes in transgenic plants. however, this technique cannot be applied to genes whose silencing may block plant regeneration or result in embryo lethality. to obviate these potential problems, we have used a chemical-inducible cre/loxp (clx) recombination system to trigger the expression of an intron-containing inverted-repeat rna (rnai) in plants. a deta ...	2003	12713544
in situ characterization of cymbidium ringspot tombusvirus infection-induced posttranscriptional gene silencing in nicotiana benthamiana.	in plants, posttranscriptional gene silencing (ptgs) is an ancient and effective defense mechanism against viral infection. a number of viruses encode proteins that suppress virus-activated ptgs. the p19 protein of tombusviruses is a potent ptgs suppressor which interferes with the onset of ptgs-generated systemic signaling and is not required for viral replication or for viral movement in nicotiana benthamiana. this unique feature of p19 suppressor allowed us to analyze the mechanism of ptgs-ba ...	2003	12719602
the potato virus x tgbp3 protein associates with the er network for virus cell-to-cell movement.	potato virus x (pvx) tgbp3 is required for virus cell-to-cell movement. cell-to-cell movement of tgbp3 was studied using biolistic bombardment of plasmids expressing gfp:tgbp3. tgbp3 moves between cells in nicotiana benthamiana, but requires tgbp1 to move in n. tabacum leaves. in tobacco leaves gfp:tgbp3 accumulated in a pattern resembling the endoplasmic reticulum (er). to determine if the er network is important for gfp:tgbp3 and for pvx cell-to-cell movement, a single mutation inhibiting memb ...	2003	12726734
p58(ipk), a plant ortholog of double-stranded rna-dependent protein kinase pkr inhibitor, functions in viral pathogenesis.	p58(ipk) is a cellular inhibitor of the mammalian double-stranded rna-activated protein kinase (pkr). here we provide evidence for the existence of its homolog in plants and its role in viral infection at the organism level. viral infection of p58(ipk)-silenced nicotiana benthamiana and arabidopsis knockouts leads to host death. this host cell death is associated with phosphorylation of the alpha subunit of eukaryotic translation initiation factor (eif-2alpha). loss of p58(ipk) leads to reduced ...	2003	12737801
use of spring beauty latent virus to identify compatible interactions between bromovirus components required for virus infection.	spring beauty latent virus (sblv) is a member of the genus bromovirus, and is closely related to brome mosaic virus (bmv) and cowpea chlorotic mottle virus (ccmv). compatible interactions between viral components are required for successful infection of plants by bmv and ccmv. to further our understanding of interactions between bromovirus components, we used sblv to produce reassortants among the three bromoviruses. we found that sblv rna 2 functioned with heterologous bromovirus rna 1 in infec ...	2003	12771403
leucine-rich repeat-mediated intramolecular interactions in nematode recognition and cell death signaling by the tomato resistance protein mi.	the root-knot nematode resistance gene mi from tomato encodes a nucleotide-binding/leucine-rich repeat (nb/lrr) protein with a novel amino-terminal domain compared to related disease-resistance genes. the closely linked paralog mi-1.1, which does not confer nematode resistance, encodes a protein 91% identical to the functional copy, mi-1.2. the chimeric construct mi-ds3, which encodes the 161 amino-terminal residues from mi-1.1 fused to the remainder of mi-1.2, induces localized necrosis when tr ...	2003	12787241
plant-based heterologous expression of mal d 2, a thaumatin-like protein and allergen of apple (malus domestica), and its characterization as an antifungal protein.	mal d 2 is a thaumatin-like protein and important allergen of apple fruits that is associated with ige-mediated symptoms in apple allergic individuals. we obtained a full-length cdna clone of mal d 2 from rna isolated from ripe apple (malus domestica cv. golden delicious). the cdna's open reading frame encodes a protein of 246 amino acid residues including a signal peptide of 24 residues and two putative glycosylation sites. the deduced amino acid sequence of the mature mal d 2 protein results i ...	2003	12787673
transient expression of arabidopsis thaliana ascorbate peroxidase 3 in nicotiana benthamiana plants infected with recombinant potato virus x.	we have explored the transient over-expression of arabidopsis thaliana ascorbate peroxidase 3 (apx3) in nicotiana benthamiana using a viral vector based on the potato virus x (pvx). plants infected with a pvx:apx3 hybrid had a similar progression of viral particles compared to control plants infected with a pvx:gfp hybrid, indicating that infection was not affected by the over-expression of heterologous apx3. our results also showed that in pvx:apx3-infected plants, the hybrid virus directed a h ...	2003	12789421
virus-induced silencing of sterol biosynthetic genes: identification of a nicotiana tabacum l. obtusifoliol-14alpha-demethylase (cyp51) by genetic manipulation of the sterol biosynthetic pathway in nicotiana benthamiana l.	obtusifoliol-14alpha-demethylase (cyp51) is implicated in plant sterol biosynthesis. an arabidopsis expressed sequence tag encoding a cyp51 was used as a probe to isolate nicotiana tabacum l. cdnas. two types of cdna clones were identified. nt cyp51-1 and nt cyp51-2 shared 97% identity together and around 75% with other plant cyp51s. the function of the encoded enzyme has been demonstrated in planta by manipulating the sterol biosynthetic pathway at the gene level. the endogenous cyp51 of nicoti ...	2003	12810855
a novel co-delivery system consisting of a tomato bushy stunt virus and a defective interfering rna for studying gene silencing.	virus induced gene silencing (vigs) and suppression are rna-specific defense and counter-defense circuits in plant-virus interactions. these phenomena have been investigated extensively with an agrobacterium-mediated transient expression system. in this study, a virus-based transient expression system was developed to study these phenomena. a tomato bushy stunt virus (tbsv) viral vector with an inactivated p19 suppressor gene, referred to as phst2-14, was chosen to express the p1 of tobacco etch ...	2003	12821195
expression of self-complementary hairpin rna under the control of the rolc promoter confers systemic disease resistance to plum pox virus without preventing local infection.	homology-dependent selective degradation of rna, or post-transcriptional gene silencing (ptgs), is involved in several biological phenomena, including adaptative defense mechanisms against plant viruses. small interfering rnas mediate the selective degradation of target rna by guiding a multicomponent rnase. expression of self-complementary hairpin rnas within two complementary regions separated by an intron elicits ptgs with high efficiency. plum pox virus (ppv) is the etiological agent of shar ...	2003	12823862
effect of temperature on plum pox virus infection.	one of the key factors of progress of an epidemic is the duration of virus availability for a vector in plants, which could be influenced by temperature. using five epidemiologically different isolates of plum pox virus (ppv) we studied the effect of temperature on the virus infectivity, intensity of disease symptoms and virus accumulation in nicotiana benthamiana plants as determined by a double-antibody sandwich-enzyme-linked immunosorbent assay (das-elisa). no differences in infectivity and i ...	2003	12828345
the pseudomonas syringae type iii-secreted protein hopptod2 possesses protein tyrosine phosphatase activity and suppresses programmed cell death in plants.	the bacterial plant pathogen pseudomonas syringae possesses a type iii protein secretion system that delivers many virulence proteins into plant cells. a subset of these proteins (called avr proteins) is recognized by the plant's innate immune system and triggers defences. one defence-associated response is the hypersensitive response (hr), a programmed cell death (pcd) of plant tissue. we have previously identified hopptod2 as a type iii secreted protein from p. s. pv. tomato dc3000. sequence a ...	2003	12828636
structural and mutational analyses of cis-acting sequences in the 5'-untranslated region of satellite rna of bamboo mosaic potexvirus.	the satellite rna of bamboo mosaic virus (satbamv) contains on open reading frame for a 20-kda protein that is flanked by a 5'-untranslated region (utr) of 159 nucleotides (nt) and a 3'-utr of 129 nt. a secondary structure was predicted for the 5'-utr of satbamv rna, which folds into a large stem-loop (lsl) and a small stem-loop. enzymatic probing confirmed the existence of lsl (nt 8-138) in the 5'-utr. the essential cis-acting sequences in the 5'-utr required for satbamv rna replication were de ...	2003	12832220
high-throughput viral expression of cdna-green fluorescent protein fusions reveals novel subcellular addresses and identifies unique proteins that interact with plasmodesmata.	a strategy was developed for the high-throughput localization of unknown expressed proteins in nicotiana benthamiana. libraries of random, partial cdnas fused to the 5' or 3' end of the gene for green fluorescent protein (gfp) were expressed in planta using a vector based on tobacco mosaic virus. viral populations were screened en masse on inoculated leaves using a confocal microscope fitted with water-dipping lenses. each viral infection site expressed a unique cdna-gfp fusion, allowing several ...	2003	12837943
virus-induced silencing of wipk and sipk genes reduces resistance to a bacterial pathogen, but has no effect on the inf1-induced hypersensitive response (hr) in nicotiana benthamiana.	activation of two mitogen-activated protein kinases (mapks), wound-induced protein kinase (wipk) and salicylic acid-induced protein kinase (sipk), is one of the earliest responses that occur in tobacco plants that have been wounded, treated with pathogen-derived elicitors or challenged with avirulent pathogens. we isolated cdnas for these mapks (nbwipkand nbsipk) from nicotiana benthamiana. the function of nbwipk and nbsipk in mediating the hypersensitive response (hr) triggered by infiltration ...	2003	12838412
the potato virus x tgbp2 protein association with the endoplasmic reticulum plays a role in but is not sufficient for viral cell-to-cell movement.	potato virus x (pvx) tgbp1, tgbp2, tgbp3, and coat protein are required for virus cell-to-cell movement. plasmids expressing gfp fused to tgbp2 were bombarded to leaf epidermal cells and gfp:tgbp2 moved cell to cell in nicotiana benthamiana leaves but not in nicotiana tabacum leaves. gfp:tgbp2 movement was observed in tgbp1-transgenic n. tabacum, indicating that tgbp2 requires tgbp1 to promote its movement in n. tabacum. in this study, gfp:tgbp2 was detected in a polygonal pattern that resembles ...	2003	12890619
two classes of subgenomic rna of grapevine virus a produced by internal controller elements.	grapevine virus a (gva), a species of the recently established genus vitivirus, consists of an approximately 7.3-kb single-stranded rna genome of positive polarity, organized into five open reading frames (orfs). the virus, which is closely associated with the grapevine rugose wood disease complex, has been poorly investigated genetically. we explored the production of viral rnas in a gva-infected nicotiana benthamiana herbaceous host and characterized one nested set of three 5'-terminal sgrnas ...	2003	12919748
identification of grapevines infected with divergent variants of grapevine virus a using variant-specific rt-pcr.	rt-pcrs, designed for the specific detection of molecular variants of grapevine virus a (gva), were applied to analysis of the virus from various grapevines and isolates recovered from these grapevines in nicotiana benthamiana. results of sscp, cloning and sequencing revealed that the combination of these rt-pcr techniques permits reliable and rapid identification of grapevines mixed-infected with divergent variants of gva. the results suggest that such grapevines are very common among gva-infec ...	2003	12951225
individualized human scfv vaccines produced in plants: humoral anti-idiotype responses in vaccinated mice confirm relevance to the tumor ig.	we have developed a method for rapidly producing in plants the idiotype regions of the tumor-specific ig as single-chain fv (scfv) proteins for use in the treatment of non-hodgkin's lymphoma. variable region gene sequences were generated from either a tumor hybridoma or human tumor biopsy cells, and idiotype domains were joined by a novel linker and cloned into a modified tobacco mosaic virus (tmv) vector designed to secrete the scfv protein in infected nicotiana benthamiana plants. thirty-eight ...	2003	12957399
fluorescent labelling reveals spatial separation of potyvirus populations in mixed infected nicotiana benthamiana plants.	the distribution of potyviruses in mixed infected nicotiana benthamiana plants was investigated by using green and red fluorescent proteins (gfp, dsred). full-length cdna clones of plum pox virus (ppv-nat-agfps; ppv-nat-red), tobacco vein mottling virus (tvmv-gfp; tvmv-red) and clover yellow vein virus (clyvv-gfp) expressing fluorescent proteins, referred to here as labelled viruses, were used to characterize the distribution of different potyviral populations (e.g. tvmv-gfp/ppv-nat-red), as wel ...	2003	13679622
suppressor activity of potyviral and cucumoviral infections in potyvirus-induced transgene silencing.	the process known as 'recovery' by which virus-infected plants become resistant to the infection is an interesting phenomenon where both rna silencing and virus resistance fully converge. in a previous study, we showed that transgenic nicotiana benthamiana nibv3 plants, transformed with a mutated nib coding sequence from plum pox virus (ppv), showed a delayed, very specific, resistance phenotype, which was induced by the initial infection. this recovery was the consequence of the activation of a ...	2003	13679623
virus-induced gene silencing.	in the postgenomic era, large-scale functional genomic approaches are necessary for converting sequence information into functional information. a para-genetic approach, called virus-induced gene silencing (vigs), offers a rapid means of gaining insight into gene function in plants. vigs system could be used to suppress endogenous gene expression by infecting plants with a recombinant virus vector (vigs vector) carrying host-derived sequence. here, we describe the use of tobacco rattle virus (tr ...	2003	14501071
bovine herpes virus gd protein produced in plants using a recombinant tobacco mosaic virus (tmv) vector possesses authentic antigenicity.	a tobacco mosaic virus (tmv)-based vector was utilized for expression of a cytosolic form of the bovine herpesvirus type 1 (bhv-1) protein glycoprotein d (gdc). nicotiana benthamiana plants were harvested 7 days after inoculation with rna transcripts derived from the tmv-gdc recombinant virus. recombinant gdc protein of expected electrophoretic mobility accumulated in inoculated leaves to a concentration of about 20 micrograms/g of fresh leaf tissue. oil-based vaccines were formulated with crude ...	2003	14505899
molecular chaperone hsp90 associates with resistance protein n and its signaling proteins sgt1 and rar1 to modulate an innate immune response in plants.	sgt1 and rar1 are important signaling components of resistance (r) gene-mediated plant innate immune responses. here we report that sgt1 and rar1 associate with the molecular chaperone hsp90. in addition, we show that hsp90 associates with the resistance protein n that confers resistance to tobacco mosaic virus. this suggests that hsp90-sgt1-rar1 and r proteins might exist in one complex. suppression of hsp90 in nicotiana benthamiana plants shows that it plays an important role in plant growth a ...	2004	14583611
functional analysis of the cloverleaf-like structure in the 3' untranslated region of bamboo mosaic potexvirus rna revealed dual roles in viral rna replication and long distance movement.	the 3' untranslated region (utr) of bamboo mosaic potexvirus (bamv) rna was identified to fold into a tertiary structure comprising a cloverleaf-like structure designated abc domain followed by a major stem-loop d, which in turn is followed by a pseudoknot e and a poly(a) tail. the coat protein accumulation level of the mutant, bamv40a/deltaabc, lacking abc domain was just 15% that of wild-type when inoculated into protoplasts of nicotiana benthamiana. this suggested that abc domain might play a ...	2003	14585345
cucumovirus- and bromovirus-encoded movement functions potentiate cell-to-cell movement of tobamo- and potexviruses.	cucumber mosaic virus (cmv, a cucumovirus) and brome mosaic virus (bmv, a bromovirus) require the coat protein (cp) in addition to the 3a movement protein (mp) for cell-to-cell movement, while cowpea chlorotic mottle virus (ccmv, a bromovirus) does not. using bombardment-mediated transcomplementation assays, we investigated whether the movement functions encoded by these viruses potentiate cell-to-cell movement of movement-defective tomato mosaic virus (tomv, a tobamovirus) and potato virus x (p ...	2003	14592759
high throughput virus-induced gene silencing implicates heat shock protein 90 in plant disease resistance.	virus-induced gene silencing was used to assess the function of random nicotiana benthamiana cdnas in disease resistance. out of 4992 cdnas tested from a normalized library, there were 79 that suppressed a hypersensitive response (hr) associated with pto-mediated resistance against pseudomonas syringae. however, only six of these clones blocked the pto-mediated suppression of p.syringae growth. the three clones giving the strongest loss of pto resistance had inserts corresponding to hsp90 and al ...	2003	14592968
synthesis of l-ascorbic acid in the phloem.	although plants are the main source of vitamin c in the human diet, we still have a limited understanding of how plants synthesise l-ascorbic acid (asa) and what regulates its concentration in different plant tissues. in particular, the enormous variability in the vitamin c content of storage organs from different plants remains unexplained. possible sources of asa in plant storage organs include in situ synthesis and long-distance transport of asa synthesised in other tissues via the phloem. in ...	2003	14633288
novel system for the simultaneous analysis of geminivirus dna replication and plant interactions in nicotiana benthamiana.	the origin of replication of african cassava mosaic virus (acmv) and a gene expression vector based on potato virus x were exploited to devise an in planta system for functional analysis of the geminivirus replication-associated protein (rep) in transgenic nicotiana benthamiana line pori-2. this line contains an integrated copy of a tandem repeat of the acmv origin of replication flanking nonviral sequences that can be mobilized and replicated by rep as an episomal replicon. a rep-gfp fusion pro ...	2003	14645587
plant sterol biosynthesis: identification of two distinct families of sterol 4alpha-methyl oxidases.	in plants, the conversion of cycloartenol into functional phytosterols requires the removal of the two methyl groups at c-4 by an enzymic complex including a sterol 4alpha-methyl oxidase (smo). we report the cloning of candidate genes for smos in arabidopsis thaliana, belonging to two distinct families termed smo1 and smo2 and containing three and two isoforms respectively. smo1 and smo2 shared low sequence identity with each other and were orthologous to the erg25 gene from saccharomyces cerevi ...	2004	14653780
the tomato resistance protein bs4 is a predicted non-nuclear tir-nb-lrr protein that mediates defense responses to severely truncated derivatives of avrbs4 and overexpressed avrbs3.	the lycopersicon esculentum bs4 resistance (r) gene specifies recognition of xanthomonas campestris pv. vesicatoria (xcv) strains that express the cognate avrbs4 avirulence protein. bs4 was isolated by positional cloning and is predicted to encode a nucleotide-binding leucine-rich repeat (nb-lrr) protein that is homologous to tobacco n and potato y-1 resistance proteins. xcv infection tests demonstrate that bs4 confers perception of avrbs4 but not the 97% identical avrbs3 protein. however, when ...	2004	14675431
gene expression analysis of plant host-pathogen interactions by supersage.	the type iii restriction endonuclease ecop15i was used in isolating fragments of 26 bp from defined positions of cdnas. we call this substantially improved variant to the conventional serial analysis of gene expression (sage) procedure "supersage." by applying supersage to magnaporthe grisea (blast)-infected rice leaves, gene expression profiles of both the rice host and blast fungus were simultaneously monitored by making use of the fully sequenced genomes of both organisms, revealing that the ...	2003	14676315
pseudomonas syringae type iii secretion system targeting signals and novel effectors studied with a cya translocation reporter.	pseudomonas syringae pv. tomato strain dc3000 is a pathogen of tomato and arabidopsis: the hrp-hrc-encoded type iii secretion system (ttss), which injects bacterial effector proteins (primarily called hop or avr proteins) into plant cells, is required for pathogenicity. in addition to being regulated by the hrpl alternative sigma factor, most avr or hop genes encode proteins with n termini that have several characteristic features, including (i) a high percentage of ser residues, (ii) an aliphat ...	2004	14702323
arg-16 and arg-21 in the n-terminal region of the triple-gene-block protein 1 of bamboo mosaic virus are essential for virus movement.	the protein encoded by the first gene of the triple gene block (tgbp1) of potexviruses is required for movement of the viruses. it has been reported that single arg-->ala substitutions at position 11, 16 or 21 of tgbp1 of bamboo mosaic virus (bamv) eliminate its rna-binding activity, while substitutions at position 16 or 21 only affect its ntpase activity (liou et al., virology 277, 336-344, 2000). however, it remains unclear whether these arg-->ala substitutions also affect the movement of bamv ...	2004	14718640
characterization and genetic diversity of potato yellow mosaic virus from the caribbean.	the begomovirus potato yellow mosaic virus (pymv) is responsible of significant yield losses in tomato in guadeloupe. four field isolates from guadeloupe were analyzed in term of their host range using three inoculation methods (mechanical, grafting and insect vector), sequences analysis of pcr fragments and phylogenetic analysis of an infectious clone, pymv-[gp]. capsicum annuum, datura stramonium, nicotiana benthamiana, n. tabacum 'xanthi nc', petunia hybrida, and solanum tuberosum were found ...	2004	14745605
proteomic analysis of the oxygen-evolving complex of photosystem ii under biotec stress: studies on nicotiana benthamiana infected with tobamoviruses.	we have previously shown that tobamovirus infection induces an inhibition of photosystem ii electron transport, disturbing the oxygen-evolving complex (oec). in the infected plants, the oec polypeptide pattern was modified when compared to healthy plants, the levels of the psbp and psbq extrinsic proteins being lowered to different extents. in this work we have further investigated by two-dimensional polyacrylamide gel electrophoresis (2-de) the changes on the oec protein pattern of thylakoid me ...	2004	14760711
plant virus expression systems for transient production of recombinant allergens in nicotiana benthamiana.	in recent years, several studies have demonstrated the use of autonomously replicating plant viruses as vehicles to express a variety of therapeutic molecules of pharmaceutical interest. plant virus vectors for expression of heterologous proteins in plants represent an attractive biotechnological tool to complement the conventional production of recombinant proteins in bacterial, fungal, or mammalian cells. virus vectors are advantageous when high levels of gene expression are desired within a s ...	2004	14962756
a cysteine-rich plant protein potentiates potyvirus movement through an interaction with the virus genome-linked protein vpg.	we have identified a cellular factor that interacts with the virus genome-linked proteins (vpgs) of a diverse range of potyviruses. the factor, called potyvirus vpg-interacting protein (pvip), is a plant-specific protein with homologues in all the species examined, i.e., pea, arabidopsis thaliana, and nicotiana benthamiana. the sequence of pvip does not identify a specific function, although the existence of a "phd finger" domain may implicate the protein in transcriptional control through chrom ...	2004	14963126
host-specific generation and maintenance of tomato bushy stunt virus defective interfering rnas.	the accumulation of tomato bushy stunt virus (tbsv) defective interfering rnas (dis) has been observed in several species of plants, but the involvement of host-specific processes and the functional role of dis are still poorly understood. in this study, the accumulation of dis was compared after several passages of tbsv through nicotiana benthamiana and pepper (capsicum annuum). as anticipated, passages of wild-type tbsv through n. benthamiana resulted in the accumulation of significant levels ...	2004	14964533
short deletions in nuclear targeting sequences of african cassava mosaic virus coat protein prevent geminivirus twinned particle formation.	coat proteins (cps) of geminiviruses are multifunctional proteins. using transient expression experiments, we have recently identified putative sequence motifs of african cassava mosaic virus (acmv) cp involved in nuclear import (nls) and export (nes) (virology 286 (2001) 373). here, we report on the effect of corresponding deletion mutants in the context of infecting viruses. since nls and nes may overlap with dna binding and multimerisation domains, we have investigated their effect on viral i ...	2004	14972538
interaction between a geminivirus replication protein and the plant sumoylation system.	geminiviruses are small dna viruses that replicate in nuclei of infected plant cells after accumulation of host replication machinery. tomato golden mosaic virus (tgmv) and tomato yellow leaf curl sardinia virus (tylcsv) encode a protein, repac1 (or rep), that is essential for viral replication. rep/repac1 is an oligomeric protein that binds to double-stranded dna, catalyzes cleavage and ligation of single-stranded dna, and is sufficient for host induction. it also interacts with several host pr ...	2004	14990696
cell-to-cell, but not long-distance, spread of rna silencing that is induced in individual epidermal cells.	a turnip crinkle virus (tcv)-based system was devised to discriminate cell-to-cell and systemic long-distance spread of rna silencing in plants. modified tcv-gfpdeltacp, constructed by replacing the coat protein (cp) gene with the green fluorescent protein (gfp) gene, replicated in single epidermal cells but failed to move from cell to cell in nicotiana benthamiana. mechanical inoculation of tcv-gfpdeltacp induced effective rna silencing in single epidermal cells which spread from cell to cell t ...	2004	14990735
in vitro recombinants of two nearly identical potyviral isolates express novel virulence and symptom phenotypes in plants.	six novel chimeric viruses were constructed by sequentially exchanging segments of the viral genomes between the infectious cdna clone (ppva-b11) of potato virus a (isolate pva-b11) and pufl, an almost identical infectious cdna of pva (isolate u) made in this study. the infectious in vitro transcripts of pufl and ppva-b11 caused similar severe mosaic and leaf malformation phenotypes in systemically infected leaves of nicotiana benthamiana. in contrast, one chimera induced a unique phenotype of y ...	2004	14993660
satellite panicum mosaic virus capsid protein elicits symptoms on a nonhost plant and interferes with a suppressor of virus-induced gene silencing.	the capsid protein (cp) of satellite panicum mosaic virus (spmv) has been implicated as a pathogenicity factor, inducing severe chlorosis on millet plants co-infected with spmv and its helper virus, panicum mosaic virus (pmv). in this study, we tested the effects of spmv cp on nicotiana benthamiana, a plant that does not support pmv+spmv infections. spmv cp expressed from a potato virus x (pvx) gene vector elicited necrotic lesions on n. benthamiana. pathogenicity factors often have the addition ...	2004	15000393
red clover necrotic mosaic virus replication proteins accumulate at the endoplasmic reticulum.	red clover necrotic mosaic virus (rcnmv) encodes n-terminally overlapping proteins of 27 and 88 kda (p27 and p88) known to be required for replication. green fluorescent protein (gfp) fusions were used to visualize the location of p27 and p88 within nicotiana benthamiana cells. gfp:p27 fusions localized to the endoplasmic reticulum (er), co-localized with er-targeted yellow fluorescent protein and caused membrane restructuring and proliferation. cellular fractionation of virus-inoculated n. bent ...	2004	15016550
virus survival of rna silencing without deploying protein-mediated suppression in nicotiana benthamiana.	rna silencing represents an evolutionarily conserved defence mechanism that plays a key antiviral role in protecting plants and animals against virus infection. to counterattack, plant, animal and fungal viruses produce proteins capable of suppressing rna silencing. here, we report an unprecedented phenomenon that potato virus x, a single-stranded positive rna virus, is able to survive rna silencing without deploying protein-mediated anti-silencing by revealing an unexpected symptom re-emergence ...	2004	15044003