Publications

characterization of avrbs3-like effectors from a brassicaceae pathogen reveals virulence and avirulence activities and a protein with a novel repeat architecture.	xanthomonas campestris pv. armoraciae strain 5 is a brassicaceae pathogen that expresses three members of the highly related avrbs3 gene family of type iii effectors. here, we report on the isolation and characterization of these genes, designated hax2, hax3, and hax4 (homolog of avrbs3 in xanthomonas). all three hax proteins are translocated from xanthomonas spp. into the plant cell via the type iii secretion system. hax3 and hax4 show the typical structure of avrbs3-like effectors and contain ...	2005	16134896
comparative analyses of six solanaceous transcriptomes reveal a high degree of sequence conservation and species-specific transcripts.	the solanaceae is a family of closely related species with diverse phenotypes that have been exploited for agronomic purposes. previous studies involving a small number of genes suggested sequence conservation across the solanaceae. the availability of large collections of expressed sequence tags (ests) for the solanaceae now provides the opportunity to assess sequence conservation and divergence on a genomic scale.	2005	16162286
gene profiling of a compatible interaction between phytophthora infestans and solanum tuberosum suggests a role for carbonic anhydrase.	late blight of potato, caused by the oomycete pathogen phytophthora infestans, is a devastating disease that can cause the rapid death of plants. to investigate the molecular basis of this compatible interaction, potato cdna microarrays were utilized to identify genes that were differentially expressed in the host during a compatible interaction with p. infestans. of the 7,680 cdna clones represented on the array, 643 (12.9%) were differentially expressed in infected plants as compared with mock ...	2005	16167762
continuous expression in tobacco leaves of a brassica napus pend homologue blocks differentiation of plastids and development of palisade cells.	brassica napus complementary deoxyribonucleic acid (cdna) clones encoding a dna-binding protein, bnpend, were isolated by southwestern screening. a distinctive feature of the protein was a bzip-like sequence in the amino-terminal portion, which, after expression in escherichia coli, bound dna. bnpend transcripts were present in b. napus roots and flower buds, and to a lesser extent in stems, flowers and young leaves. treatment in the dark for 72 h markedly increased the amount of bnpend transcri ...	2005	16167891
expression, localization and effects on virulence of the cysteine-rich 8 kda protein of potato mop-top virus.	potato mop-top virus (pmtv) rna3 contains a triple gene block (tgb) encoding viral movement proteins and an open reading frame for a putative 8 kda cysteine-rich protein (crp). in this study, pmtv crp was shown to be expressed in the course of virus infection, and a pmtv crp-specific subgenomic rna was mapped. crp has previously been shown to be dispensable for infection of pmtv in nicotiana benthamiana. in this study, pmtv crp was found to increase the severity of disease symptoms when expresse ...	2005	16186244
identification of an rna silencing suppressor from a plant double-stranded rna virus.	rna silencing is a mechanism which higher plants and animals have evolved to defend against viral infection in addition to regulation of gene expression for growth and development. as a counterdefense, many plant and some animal viruses studied to date encode rna silencing suppressors (rss) that interfere with various steps of the silencing pathway. in this study, we report the first identification of an rss from a plant double-stranded rna (dsrna) virus. pns10, encoded by s10 of rice dwarf phyt ...	2005	16189004
inducible expression in plants by virus-mediated transgene activation.	we have developed a plant virus-mediated transgene activation (vmta) system that utilizes a viral expression vector to present the inducer. the concept was tested using two well characterized components: (i) an artificial promoter based on the yeast gal4 upstream activating sequence and the minimal tata element of cauliflower mosaic virus 35s rna promoter, and (ii) a transcriptional activator (ta) consisting of a fusion between the gal4 dna binding domain and the herpes simplex virus vp16 activa ...	2005	16201407
production of an engineered killer peptide in nicotiana benthamiana by using a potato virus x expression system.	the decapeptide killer peptide (kp) derived from the sequence of a single-chain, anti-idiotypic antibody acting as a functional internal image of a microbicidal, broad-spectrum yeast killer toxin (kt) was shown to exert a strong microbicidal activity against human pathogens. with the aim to exploit this peptide to confer resistance to plant pathogens, we assayed its antimicrobial activity against a broad spectrum of phytopathogenic bacteria and fungi. synthetic kp exhibited antimicrobial activit ...	2005	16204558
development and assessment of a potato virus x-based expression system with improved biosafety.	over the last decade, plant virus-based vectors have been developed and successfully exploited for high-yield production of heterologous proteins in plants. however, widespread application of recombinant viruses raises concerns about possible risks to the environment. one of the primary safety issues that must be considered is the uncontrolled spread of the genetically engineered virus from experimental plants to susceptible weeds or crops. using a movement-deficient potato virus x (pvx)-based t ...	2005	16209135
basal resistance against bacteria in nicotiana benthamiana leaves is accompanied by reduced vascular staining and suppressed by multiple pseudomonas syringae type iii secretion system effector proteins.	basal resistance in plants is induced by flagellin and several other common bacterial molecules and is implicated in the immunity of plants to most bacteria and other microbes. however, basal resistance can be suppressed by effector proteins that are injected by the type iii secretion system (ttss) of pathogens such as pseudomonas syringae. this study demonstrates that basal resistance in the leaves of nicotiana benthamiana is accompanied by reduced vascular flow into minor veins. reduced vascul ...	2005	16212612
analysis of rna silencing in agroinfiltrated leaves of nicotiana benthamiana and nicotiana tabacum.	in this study we analyse several aspects of cytoplasmic rna silencing by agroinfiltration of dna constructs encoding single- and double-stranded rnas derived from a gfp transgene and from the endogenous virp1 gene. both types of inductors resulted after 2-4 days in much higher concentration of sirnas in the agroinfiltrated zone than normally seen during systemic silencing. more specifically, infiltration of two transgene hairpin constructs resulted in elevated levels of sirnas. however, differen ...	2005	16244913
interaction between brome mosaic virus proteins and rnas: effects on rna replication, protein expression, and rna stability.	brome mosaic virus (bmv) rna replication has been examined in a number of systems, including saccharomyces cerevisiae. we developed an efficient t-dna-based gene delivery system using agrobacterium tumefaciens to transiently express bmv rnas in nicotiana benthamiana. the expressed rnas can systemically infect plants and provide material to extract bmv replicase that can perform template-dependent rna-dependent rna synthesis in vitro. we also expressed the four bmv-encoded proteins from nonreplic ...	2005	16254357
tobacco transcription factor wrky1 is phosphorylated by the map kinase sipk and mediates hr-like cell death in tobacco.	the salicylic acid-induced protein kinase (sipk) of tobacco, which is a mitogen-activated protein kinase (mapk), is activated by various biotic and abiotic treatments. overexpression of sipk has been shown to trigger cell death. in this study, a targeted yeast two-hybrid approach identified the tobacco transcription factor wrky1 as a potential substrate. sipk phosphorylated wrky1, which resulted in enhanced dna-binding activity of wrky1 to its cognate binding site, a w box sequence from the toba ...	2005	16255241
genetic analysis of the function of the plum pox virus ci rna helicase in virus movement.	the ci protein forms the cylindrical inclusions typical of potyviral infections and is involved in genome replication and virus movement. in this work, we have analyzed the effect of a series of point mutations at the n-terminal region of the ci protein of plum pox virus (ppv) on the enzymatic activities and the self-interaction ability of the protein, and on virus replication and movement. dd3,4aa mutation, which had no apparent effects on atpase and rna helicase activities in vitro, and on vir ...	2006	16256236
purification of transgenic plant-derived recombinant human acetylcholinesterase-r.	nicotiana benthamiana plants were engineered to express a codon-optimized gene encoding the human acetylcholinesterase-r (ache) isoform. the transgenic plants expressed the protein at >0.4% of total soluble protein, and the plant-produced enzyme was purified to homogeneity. following lysis, procainamide affinity chromatography and anion-exchange chromatography, more than 400-fold purification was achieved and electrophoretic purity was obtained. this pure protein is kinetically indistinguishable ...	2005	16269140
the aauaaa motif of bamboo mosaic virus rna is involved in minus-strand rna synthesis and plus-strand rna polyadenylation.	bamboo mosaic virus (bamv) has a single-stranded positive-sense rna genome with a 5'-cap structure and a 3' poly(a) tail. deleting the internal loop that contains the putative polyadenylation signal (aauaaa) in the 3' untranslated region (utr) of bamv genomic rna appeared to diminish coat protein accumulation to 2% (c. p. cheng and c. h. tsai, j. mol. biol. 288:555-565, 1999). to investigate the function of the aauaaa motif, mutations were introduced into an infectious bamv cdna at each residue ...	2005	16282455
p1- and vpg-transgenic plants show similar resistance to potato virus a and may compromise long distance movement of the virus in plant sections expressing rna silencing-based resistance.	nicotiana benthamiana was transformed with p1 or vpg cistron of potato virus a (pva, genus potyvirus). for both transgenes, t1 progeny displayed (i) resistance to pva infection, (ii) susceptibility, or (iii) systemic infection followed by recovery of new leaves from pva infection (rc), regardless of the transgene. in rc plants, fully recovered leaves contained no detectable pva rna, were highly resistant to challenge inoculation with pva, and had barely detectable steady-state levels of transgen ...	2006	16298007
engineering the genome of grapevine virus a into a vector for expression of proteins in herbaceous plants.	grapevine virus a (gva), a species of the genus vitivirus, consists of a approximately 7.4 kb single-stranded rna genome of positive polarity, organized into five open reading frames (orfs). in addition to grape varieties, gva infects nicotiana benthamiana plants and protoplasts. we engineered the genome of gva as a vector that includes duplication of homologous sequences that contain the promoter of the movement protein (mp) sgrna, supplemented by enzymatic restriction sites to be used as a con ...	2006	16298435
involvement of pps3 phosphorylated by elicitor-responsive mitogen-activated protein kinases in the regulation of plant cell death.	mitogen-activated protein kinase (mapk) cascades play pivotal roles in plant innate immunity. overexpression of stmek1(dd), a constitutively active mapk kinase that activates salicylic acid-induced protein kinase (sipk) and wound-induced protein kinase (wipk), provokes hypersensitive response-like cell death in nicotiana benthamiana. here we purified a 51-kd mapk, which was activated in potato (solanum tuberosum) tubers treated with hyphal wall elicitor of a plant pathogen, and isolated the cdna ...	2005	16306147
rdr6 has a broad-spectrum but temperature-dependent antiviral defense role in nicotiana benthamiana.	sde1/sgs2/rdr6, a putative rna-dependent rna polymerase (rdrp) from arabidopsis thaliana, has previously been found to be indispensable for maintaining the posttranscriptional silencing of transgenes, but it is seemingly redundant for antiviral defense. to elucidate the antiviral role of this rdrp in a different host plant and to evaluate whether plant growth conditions affect its role, we down-regulated expression of the nicotiana benthamiana homolog, nbrdr6, and examined the plants for altered ...	2005	16306592
hairpin rna-mediated silencing of plum pox virus p1 and hc-pro genes for efficient and predictable resistance to the virus.	we report the application of the hairpin-mediated rna silencing technology for obtaining resistance to plum pox virus (ppv) infection in nicotiana benthamiana plants. four sequences, covering the p1 and silencing suppressor hc-pro genes of an italian ppv m isolate, were introduced into n. benthamiana plants as two inverted repeats separated by an intron sequence under the transcriptional control of the cauliflower mosaic virus 35s promoter. in a leaf disk infection assay, 38 out of 40 t0 transge ...	2005	16315100
identification of a twin-arginine translocation system in pseudomonas syringae pv. tomato dc3000 and its contribution to pathogenicity and fitness.	the bacterial plant pathogen pseudomonas syringae pv. tomato dc3000 (dc3000) causes disease in arabidopsis thaliana and tomato plants, and it elicits the hypersensitive response in nonhost plants such as nicotiana tabacum and nicotiana benthamiana. while these events chiefly depend upon the type iii protein secretion system and the effector proteins that this system translocates into plant cells, additional factors have been shown to contribute to dc3000 virulence and still many others are likel ...	2005	16321949
pepper mild mottle virus pathogenicity determinants and cross protection effect of attenuated mutants in pepper.	to determine the pathogenicity domain and to apply cross protection, pepper mild mottle virus (pmmov) point-mutations in the replicase (rep) gene between the methyl-transferase and helicase domains, and deletions truncating pseudoknots in the 3' non-coding region (ncr), were constructed. some mutants substituting a single amino acid in rep residue 348 exhibited mild symptoms in nicotiana benthamiana or pepper plants. accumulation of these mutants was higher than that of other rep mutants or wild ...	2006	16325950
identification of sequence elements of tombusvirus-associated defective interfering rnas required for symptom modulation.	defective interfering (di) rnas of tombusviruses are short, non-coding, symptom-modulating rnas originating from the viral genome. the presence of homologous di rna in virus infection attenuates the otherwise lethal viral symptoms. nicotiana benthamiana plants infected with tomato bushy stunt tombusvirus pepper isolate (tbsv-p) show severe symptoms, which culminate in the death of the plant. in contrast, plants co-inoculated with tbsv-p and tbsv-p-derived di rna display attenuated symptoms. howe ...	2006	16328149
a novel thioredoxin h is secreted in nicotiana alata and reduces s-rnase in vitro.	thioredoxins type h are classified into three subgroups. the subgroup ii includes thioredoxins containing an n-terminal extension, the role of which is still unclear. although thioredoxin secretion has been observed in animal cells, there is no evidence suggesting that any thioredoxin h is secreted in plants. in this study, we report that a thioredoxin h, subgroup ii, from nicotiana alata (natrxh) is secreted into the extracellular matrix of the stylar transmitting tract tissue. fractionation st ...	2006	16354655
transient expression vectors for functional genomics, quantification of promoter activity and rna silencing in plants.	we describe novel plasmid vectors for transient gene expression using agrobacterium, infiltrated into nicotiana benthamiana leaves. we have generated a series of pgreenii cloning vectors that are ideally suited to transient gene expression, by removing elements of conventional binary vectors necessary for stable transformation such as transformation selection genes.	2005	16359558
tomato pto encodes a functional n-myristoylation motif that is required for signal transduction in nicotiana benthamiana.	pto kinase of tomato (lycopersicon esculentum) confers resistance to bacterial speck disease caused by pseudomonas syringae pv. tomato expressing avrpto or avrptob. pto interacts directly with these type-iii secreted effectors, leading to induction of defence responses including the hypersensitive response (hr). signalling by pto requires the nucleotide-binding site-leucine-rich repeat (nbs-lrr) protein prf. little is known of how pto is controlled prior to or during stimulation, although kinase ...	2006	16367952
elicitor-mediated oligomerization of the tobacco n disease resistance protein.	plant nucleotide binding site-leucine-rich repeat (nbs-lrr) proteins are similar to the nucleotide binding oligomerization domain (nod) protein family in their domain structure. it has been suggested that most nod proteins rely on ligand-mediated oligomerization for function, and we have tested this possibility with the n protein of tobacco (nicotiana tabacum). the n gene for resistance to tobacco mosaic virus (tmv) is a member of the toll-interleukin receptor (tir)-nbs-lrr class of plant diseas ...	2006	16387833
transgenic plants regenerated from hairy roots of nicotiana benthamiana: a promising host for transient expression of foreign proteins.	hairy root cultures of nicotiana benthamiana have been obtained by co-cultivation of leaf explants with agrobacterium rhizogenes strain a4 harboring a binary vector plasmid, and transgenic nature of the obtained cultures was confirmed by pcr analysis. transgenic plants were regenerated from hairy roots. the biomass yield of transgenic plants grown in vitro was almost two-fold higher than those of wild-type n. benthamiana plants. they differed from untransformed plants by short internodes, reinfo ...	2005	16396315
silencing an acc oxidase gene affects the susceptible host response of nicotiana benthamiana to infection by colletotrichum orbiculare.	an 1-aminocyclopropane-1-carboxylic acid (acc) oxidase, nbaco1, was cloned from cdna of nicotiana benthamiana leaves infected with the hemibiotrophic fungal pathogen, colletotrichum orbiculare. expression of nbaco1 increased approximately 3-fold by 24 h after inoculation and then continued to increase reaching a maximum that was 6-folds greater than that in healthy plants by 96 h after inoculation. a portion of nbaco1 was cloned into a pvx vector for virus-induced gene silencing, and the silenci ...	2006	16397784
ethylene sensing and gene activation in botrytis cinerea: a missing link in ethylene regulation of fungus-plant interactions?	ethylene production by infected plants is an early resistance response leading to activation of plant defense pathways. however, plant pathogens also are capable of producing ethylene, and ethylene might have an effect not only on the plant but on the pathogen as well. therefore, ethylene may play a dual role in fungus-plant interactions by affecting the plant as well as the pathogen. to address this question, we studied the effects of ethylene on the gray mold fungus botrytis cinerea and the di ...	2006	16404951
protection conferred by recombinant yersinia pestis antigens produced by a rapid and highly scalable plant expression system.	plague is still an endemic disease in different regions of the world. increasing reports of incidence, the discovery of antibiotic resistance strains, and concern about a potential use of the causative bacteria yersinia pestis as an agent of biological warfare have highlighted the need for a safe, efficacious, and rapidly producible vaccine. the use of f1 and v antigens and the derived protein fusion f1-v has shown great potential as a protective vaccine in animal studies. plants have been exten ...	2006	16410352
a modified viral satellite dna-based gene silencing vector is effective in association with heterologous begomoviruses.	we have previously reported effective gene silencing of a transgene and endogenous plant genes in tobacco and tomato plants using a modified viral satellite dna associated with tomato yellow leaf curl china virus (tylccnv). in this study, we constructed a similar gene silencing vector (dnadeltac12beta) based on the satellite dnabeta associated with tobacco curly shoot virus (tbcsv) by replacing its betac1 gene with a multiple cloning site. strong and stable silencing of cognate genes was achieve ...	2006	16417940
rapid, high-level production of hepatitis b core antigen in plant leaf and its immunogenicity in mice.	hepatitis b core antigen (hbc or hbcag) self-assembles into capsid particles and is extremely immunogenic. hbc has been extensively studied for its production in various expression systems and for the use of hbc particles for high-density, immunogenic presentation of foreign epitopes. here we reported the high-level transient expression of hbc in plant leaf and its immunogenicity in mice. by using a novel plant viral expression system, hbc was produced in nicotiana benthamiana leaves at levels u ...	2006	16417953
molecular characterization of geminivirus-derived small rnas in different plant species.	dna geminiviruses are thought to be targets of rna silencing. here, we characterize small interfering (si) rnas-the hallmarks of silencing-associated with cabbage leaf curl begomovirus in arabidopsis and african cassava mosaic begomovirus in nicotiana benthamiana and cassava. we detected 21, 22 and 24 nt sirnas of both polarities, derived from both the coding and the intergenic regions of these geminiviruses. genetic evidence showed that all the 24 nt and a substantial fraction of the 22 nt vira ...	2006	16421273
identification and characterization of the arabidopsis orthologs of nuclear transport factor 2, the nuclear import factor of ran.	ran is a multifunctional small gtpase that is involved in nucleocytoplasmic transport, mitotic spindle assembly, and nuclear envelope formation. nuclear import of ran relies on a small rangdp-binding protein, nuclear transport factor 2 (ntf2). three proteins are expressed in arabidopsis (arabidopsis thaliana) that show significant sequence similarity to human and yeast (saccharomyces cerevisiae) ntf2. here, we demonstrate that two of them, atntf2a and atntf2b, can functionally replace the essent ...	2006	16428596
the interaction between dcl1 and hyl1 is important for efficient and precise processing of pri-mirna in plant microrna biogenesis.	it has been reported that some double-stranded rna (dsrna) binding proteins interact with small rna biogenesis-related rnase iii enzymes. however, their biological significance is poorly understood. here we examine the relationship between the arabidopsis microrna- (mirna) producing enzyme dcl1 and the dsrna binding protein hyl1. in the hyl1-2 mutant, the processing steps of mir163 biogenesis were partially impaired; increased accumulation of pri-mir163 and reduced accumulation of short pre-mir1 ...	2006	16428603
biological properties of beet mild yellowing virus derived from a full-length cdna clone.	a german isolate of beet mild yellowing virus (bmyv-ipp) was used for rt-pcr-based construction of the first infectious full-length cdna clone of the virus (bmyv(fl)). the complete genomic sequence was determined and displayed high similarity to the french isolate bmyv-2itb. the host range of bmyv(fl) was examined by agroinoculation and aphid transmission. both methods lead to systemic infections in beta vulgaris, nicotiana benthamiana, n. clevelandii, n. hesperis, capsella bursa-pastoris and la ...	2006	16432033
rnai dependent epigenetic marks on a geminivirus promoter.	nicotiana benthamiana plants were stably transformed with an intron-spliced dsrna producing construct cognate to bidirectional promoter of african cassava mosaic geminivirus (acmv) dna a. transgenic lines expressed multiple sirnas species upon acmv infection. the de novo dna methylation and an increased proportion of histone h3 lysine-9 methylation (h3k9) at intergenic region (igr) of acmv dna a were observed.	2006	16445863
f-box-like domain in the polerovirus protein p0 is required for silencing suppressor function.	plants employ small rna-mediated posttranscriptional gene silencing as a virus defense mechanism. in response, plant viruses encode proteins that can suppress rna silencing, but the mode of action of most such proteins is poorly understood. here, we show that the silencing suppressor protein p0 of two arabidopsis-infecting poleroviruses interacts by means of a conserved minimal f-box motif with arabidopsis thaliana orthologs of s-phase kinase-related protein 1 (skp1), a component of the scf fami ...	2006	16446454
genetic analysis of tomato golden mosaic virus: the coat protein is not required for systemic spread or symptom development.	the geminiviruses are a unique group of higher plant viruses that are composed of twin isometric particles which contain circular, single-stranded dna. tomato golden mosaic virus (tgmv), a whitefly-transmitted agent, belongs to the subgroup of geminiviruses whose members possess a bipartite genome. the tgmv a genome component has the capacity to encode at least four proteins. one of these is the viral coat protein, as inferred by homology with coat-protein, genes of other geminiviruses and by th ...	1988	16453835
expression of a bacterial gene in plants mediated by infectious geminivirus dna.	a viable coat protein deletion mutant of cassava latent virus (clv) dna 1 has been isolated, suggesting that this geminivirus might be exploited as a gene replacement vector. an extensive deletion of 727 nucleotides within the coat protein gene renders dna 1 non-infectious. chimeric clones have been constructed in which the deleted coat protein open reading frame has been replaced by the coding region of the bacterial chloramphenicol acetyl transferase (cat) gene. infectivity is restored to dna ...	1988	16453850
studies on the activity of a bidirectional promoter of mungbean yellow mosaic india virus by agroinfiltration.	the av promoter expressing av1 and av2 genes and ac1 promoter expressing ac1 gene are present in opposite orientation in the intergenic region of mungbean yellow mosaic india virus (mymiv). transient agrobacterium-mediated delivery of putative promoter constructs into nicotiana benthamiana and different legumes, followed by reporter gene (beta-d-glucuronidase, gus) assay, identified the promoter region of both ac1 and av genes that is necessary for transcriptional initiation. transcription activ ...	2006	16458986
crucial role of the 5' conserved structure of bamboo mosaic virus satellite rna in downregulation of helper viral rna replication.	satellite rna of bamboo mosaic virus (satbamv), a single-stranded mrna type satellite encoding a protein of 20 kda (p20), depends on the helper bamv for replication and encapsidation. two satbamv isolates, bsf4 and bsl6, exhibit distinctly differential phenotypes in nicotiana benthamiana plants when coinoculated with bamv rna. bsl6 significantly reduces bamv rna replication and suppresses the bamv-induced symptoms, whereas bsf4 does not. by studies with chimeric satbamvs generated by exchanging ...	2006	16474162
epitope presentation system based on cucumber mosaic virus coat protein expressed from a potato virus x-based vector.	the cucumber mosaic virus ixora isolate (cmv) coat protein gene (cp) was placed under the transcriptional control of the duplicated subgenomic cp promoter of a potato virus x (pvx)-based vector. in vitro rna transcripts were inoculated onto nicotiana benthamiana plants and recombinant cmv capsid proteins were identified on western blots probed with cmv antibodies 5-7 days post-inoculation. pvx-produced cmv cp subunits were capable of assembling into virus-like particles (vlps), which were visual ...	2006	16489509
biological relevance of a stable biochemical interaction between the tombusvirus-encoded p19 and short interfering rnas.	the tomato bushy stunt virus (tbsv)-encoded p19 protein (p19) is widely used as a robust tool to suppress rna interference (rnai) in various model organisms. p19 dimers appropriate 21-nucleotide (nt) duplex short interfering rnas (sirnas) generated by dicer presumably to prevent programming of the rna-induced silencing complex (risc). in the context of virus infection, this model predicts that p19 mutants compromised for sirna binding cannot prevent risc-mediated degradation of tbsv rna and thus ...	2006	16501109
spontaneous short-range silencing of a gfp transgene in nicotiana benthamiana is possibly mediated by small quantities of sirna that do not trigger systemic silencing.	a green fluorescent protein (gfp) transgene under the control of the 35s cauliflower mosaic virus (camv) promoter was introduced by agrobacterium-mediated transformation into nicotiana benthamiana to generate fourteen transgenic lines. homozygous lines that contained one or two copies of the transgene showed great variation of gfp expression under ultraviolet (uv) light, which allowed classification into three types of transgenic plants. plants from more than half of the transgenic lines underwe ...	2006	16507090
an in vivo, luciferase-based, agrobacterium-infiltration assay system: implications for post-transcriptional gene silencing.	an in vivo assay system for analyzing transient luciferase expression in tobacco leaves infused with agrobacterium tumefaciens is described. the system makes use of a. tumefaciens harboring t-dna vectors containing either an intron-containing firefly (photinus pyralis) luciferase (ec 1.13.12.7) gene or an intron-containing sea pansy (renilla reniformis) luciferase (ec 1.13.12.5) gene. single or mixed agrobacterium lines were infiltrated into leaf tissues (nicotiana tabacum or nicotiana benthamia ...	2006	16523348
transient expression of human papillomavirus type 16 l1 protein in nicotiana benthamiana using an infectious tobamovirus vector.	a tobacco mosaic virus (tmv)-derived vector was used to express a native human papillomavirus type 16 (hpv-16) l1 gene in nicotiana benthamiana by means of infectious in vitro rna transcripts inoculated onto n. benthamiana plants. hpv-16 l1 protein expression was quantitated by enzyme-linked immunosorbent assays (elisa) after concentration of the plant extract. we estimated that the l1 product yield was 20-37 microg/kg of fresh leaf material. the l1 protein in the concentrated extract was antige ...	2006	16530873
xanthan induces plant susceptibility by suppressing callose deposition.	xanthan is the major exopolysaccharide secreted by xanthomonas spp. despite its diverse roles in bacterial pathogenesis of plants, little is known about the real implication of this molecule in xanthomonas pathogenesis. in this study we show that in contrast to xanthomonas campestris pv campestris strain 8004 (wild type), the xanthan minus mutant (strain 8397) and the mutant strain 8396, which is producing truncated xanthan, fail to cause disease in both nicotiana benthamiana and arabidopsis (ar ...	2006	16531487
the u-box protein cmpg1 is required for efficient activation of defense mechanisms triggered by multiple resistance genes in tobacco and tomato.	we previously identified three avr9/cf-9 rapidly elicited (acre) genes essential for cf-9- and cf-4-dependent hypersensitive response (hr) production in nicotiana benthamiana. two of them encode putative e3 ubiquitin ligase components. this led us to investigate other acre genes associated with the ubiquitination pathway. acre74 encodes a u-box e3 ligase homolog, highly related to parsley (petroselinum crispum) cmpg1 and arabidopsis thaliana plant u-box20 (pub20) and pub21 proteins, and was call ...	2006	16531490
a versatile transreplication-based system to identify cellular proteins involved in geminivirus replication.	a versatile green fluorescent protein (gfp) expression cassette containing the replication origins of the monopartite begomovirus tomato yellow leaf curl sardinia virus (tylcsv) is described. transgenic nicotiana benthamiana plants containing one copy of the cassette stably integrated into their genome were superinfected with tylcsv, which mobilized and replicated the cassette as an episomal replicon. the expression of the reporter gene (the gfp gene) was thereby modified. whereas gfp fluorescen ...	2006	16537630
exploiting the plant secretory pathway to improve the anticancer activity of a plant-derived hpv16 e7 vaccine.	the human papillomavirus 16 (hpv16) e7 oncoprotein can be considered a "tumor-specific antigen", and therefore it represents a promising target for a therapeutic vaccine against hpv-associated tumors. efficient production of e7 protein with a plant-based transient expression system has been already described and it was demonstrated that e7-containing crude plant extracts confer partial protection against tumor challenge in a mouse model system. before adopting the plant-based system as a cost-ef ...	2006	16569357
identification of a plum pox virus ci-interacting protein from chloroplast that has a negative effect in virus infection.	the cylindrical inclusion (ci) protein of potyviruses is involved in virus replication and cell-to-cell movement. these two processes should rely on multiple plant-virus interactions; however, little is known about the host factors that are involved in, or that may interfere with, ci functions. by using a yeast two-hybrid system, the ci protein from plum pox virus (ppv) was found to interact with the photosystem i psi-k protein, the product of the gene psak, of nicotiana benthamiana. coexpressio ...	2006	16570664
optimization of transient agrobacterium-mediated gene expression system in leaves of nicotiana benthamiana.	here we report on a simple and reproducible system of agrobacterium-mediated transient gene expression assay that utilizes infiltration of young nicotiana benthamiana leaves. although some of the phenomena described in this paper have been already reported by other researchers, here we have further developed them. the highest level of transient gfp gene expression was detected in the youngest leaves of n. benthamiana infiltrated with a. tumefaciens strains agl0 and eha105 precultured in the pres ...	2006	16582986
nitrate reductase is responsible for elicitin-induced nitric oxide production in nicotiana benthamiana.	recent works have established a key role for nitric oxide (no) in activating disease resistance in plants. nitrate reductase (nr) is one of the enzymes that are capable of producing no in plants. in a previous study, we reported that pathogen signals induce expression of nr genes in potato, suggesting the involvement of nr in no production induced by pathogen signals. in this study, we cloned nr genes from nicotiana benthamiana and investigated their involvement in no production induced by inf1, ...	2006	16608868
efficient transient expression of human gm-csf protein in nicotiana benthamiana using potato virus x vector.	the human granulocyte macrophage colony-stimulating factor (gm-csf) is a glycoprotein with important clinical applications for the treatment of neutropenia and aplastic anemia and reducing infections associated with bone marrow transplants. we evaluated the potential for using a potato virus x (pvx) viral vector system for efficient expression of the biologically functional gm-csf protein in nicotiana benthamiana leaves. the gm-csf gene was cloned into pvx viral expression vector, driven with th ...	2006	16612640
role of sgt1 in resistance protein accumulation in plant immunity.	a highly conserved eukaryotic protein sgt1 binds specifically to the molecular chaperone, hsp90. in plants, sgt1 positively regulates disease resistance conferred by many resistance (r) proteins and developmental responses to the phytohormone, auxin. we show that silencing of sgt1 in nicotiana benthamiana causes a reduction in steady-state levels of the r protein, rx. these data support a role of sgt1 in r protein accumulation, possibly at the level of complex assembly. in arabidopsis, two sgt1 ...	2006	16619029
virus-induced gene silencing of argonaute genes in nicotiana benthamiana demonstrates that extensive systemic silencing requires argonaute1-like and argonaute4-like genes.	several distinct pathways of rna silencing operate in plants with roles including the suppression of virus accumulation, control of endogenous gene expression, and direction of dna and chromatin modifications. proteins of the dicer-like and argonaute (ago) families have key roles within these silencing pathways and have distinct biochemical properties. we are interested in the relationships between different silencing pathways and have used nicotiana benthamiana as a model system. while not bein ...	2006	16632593
prohibitin is involved in mitochondrial biogenesis in plants.	prohibitin, which consists of two subunits phb1 and phb2, plays a role in cell-cycle progression, senescence, apoptosis, and maintenance of mitochondrial function in mammals and yeast. in this study, we examined the role of prohibitins in plants by using virus-induced gene silencing (vigs) of two prohibitin subunit genes of nicotiana benthamiana, designated nbphb1 and nbphb2. nbphb1 and nbphb2 were targeted to the mitochondria, and their gene expression was suppressed during senescence. vigs of ...	2006	16640602
tobamovirus infection is independent of hsp101 mrna induction and protein expression.	heat shock protein 101 (hsp101) has been implicated in tobamovirus infections by virtue of its ability to enhance translation of mrnas possessing the 5'omega-leader of tobacco mosaic virus (tmv). enhanced translation is mediated by hsp101 binding to a caa-repeat motif in tmv omega leader. caa repeat sequences are present in the 5' leaders of other tobamoviruses including oilseed rape mosaic virus (ormv), which infects arabidopsis thaliana. hsp101 is one of eight hsp100 gene family members encode ...	2006	16644052
the role of the c-terminal region of olive latent virus 1 coat protein in host systemic infection.	a full-length cdna clone of olive latent virus 1 (olv-1), a member of the genus necrovirus, family tombusviridae, was subjected to site-directed mutagenesis, and coat protein gene mutants were constructed. a mutant clone, denoted delta3297, was obtained by deleting the nucleotide in position 3297, thus inducing a frameshift and replacing the last 49 amino acids of the viral coat protein (cp) by a shorter sequence of 39 amino acids. this mutant was viable, stable, able to synthesize a smaller cp, ...	2006	16699830
role of the leader sequence in tobacco pectin methylesterase secretion.	we report that unprocessed tobacco pectin methylesterase (pme) contains n-terminal pro-sequence including the transmembrane (tm) domain and spacer segment preceding the mature pme. the mature portion of pme was replaced by green fluorescent protein (gfp) gene and various deletion mutants of pro-sequence fused to gfp were cloned into binary vectors and agroinjected in nicotiana benthamiana leaves. the pme pro-sequence delivered gfp to the cell wall (cw). we showed that a transient binding of pme ...	2006	16709413
perception of the bacterial pamp ef-tu by the receptor efr restricts agrobacterium-mediated transformation.	higher eukaryotes sense microbes through the perception of pathogen-associated molecular patterns (pamps). arabidopsis plants detect a variety of pamps including conserved domains of bacterial flagellin and of bacterial ef-tu. here, we show that flagellin and ef-tu activate a common set of signaling events and defense responses but without clear synergistic effects. treatment with either pamp results in increased binding sites for both pamps. we used this finding in a targeted reverse-genetic ap ...	2006	16713565
capsid protein gene and the type of host plant differentially modulate cell-to-cell movement of cowpea chlorotic mottle virus.	a study was undertaken to measure the rate of coat protein (cp) independent cell-to-cell movement of cowpea chlorotic mottle bromovirus (ccmv) in three different host plants. a ccmv rna3 variant in which the cp gene was substituted with enhanced green fluorescent protein (c3/deltacp-egfp) was coinoculated to three different host plants with transcripts of wild type rnas 1 and 2. comparative analysis of cell-to-cell movement monitored by the egfp expression at various days post inoculation reveal ...	2006	16732474
hypovirus papain-like protease p29 suppresses rna silencing in the natural fungal host and in a heterologous plant system.	virulence-attenuating hypoviruses of the species cryphonectria hypovirus 1 (chv1) encode a papain-like protease, p29, that shares similarities with the potyvirus-encoded suppressor of rna silencing hc-pro. we now report that hypovirus chv1-ep713-encoded p29 can suppress rna silencing in the natural host, the chestnut blight fungus cryphonectria parasitica. hairpin rna-triggered silencing was suppressed in c. parasitica strains expressing p29, and transformation of a transgenic green fluorescent ...	2006	16757737
cdna-aflp combined with functional analysis reveals novel genes involved in the hypersensitive response.	to identify genes required for the hypersensitive response (hr), we performed expression profiling of tomato plants mounting a synchronized hr, followed by functional analysis of differentially expressed genes. by cdna-aflp analysis, the expression profile of tomato plants containing both the cf-4 resistance gene against cladosporium fulvum and the matching avr4 avirulence gene of this fungus was compared with that of control plants. about 1% of the transcript-derived fragments (442 out of 50,00 ...	2006	16776290
atrli2 is an endogenous suppressor of rna silencing.	rna silencing is a mechanism involved in gene regulation during development and anti-viral defense in plants and animals. although many viral suppressors of this mechanism have been described up to now, this is not the case for endogenous suppressors. we have identified a novel endogenous suppressor in plants: rnase l inhibitor (rli) of arabidopsis thaliana. rli is a very conserved protein among eukaryotes and archaea. it was first known as component of the interferon-induced mammalian 2'-5' oli ...	2006	16786298
in planta production of two peptides of the classical swine fever virus (csfv) e2 glycoprotein fused to the coat protein of potato virus x.	classical swine fever (csfv) is one of the most important viral infectious diseases affecting wild boars and domestic pigs. the etiological agent of the disease is the csf virus, a single stranded rna virus belonging to the family flaviviridae. all preventive measures in domestic pigs have been focused in interrupting the chain of infection and in avoiding the spread of csfv within wild boars as well as interrupting transmission from wild boars to domestic pigs. the use of plant based vaccine ag ...	2006	16792815
a novel function for a ubiquitous plant enzyme pectin methylesterase: the enhancer of rna silencing.	co-agroinjection of nicotiana benthamiana leaves with the pectin methylesterase (propme) gene and the tmv:gfp vector resulted in a stimulation of virus-induced rna silencing (inhibition of gfp production, virus rna degradation, stimulation of sirnas production). conversely, co-expression of tmv:gfp with either antisense pme construct or with enzymatically inactive propme restored synthesis of viral rna. furthermore, expression of propme enhanced the gfp transgene-induced gene silencing accompani ...	2006	16797009
a simplified method for cloning of short interfering rnas from brassica juncea infected with turnip mosaic potyvirus and turnip crinkle carmovirus.	rna silencing is a plant defense mechanism in which virus infected plants produce short interfering rnas (sirnas) derived from viral rna, that attack the virus at the post-transcriptional level. in a previous study on cymbidium ringspot tombusvirus (cymrsv) infection in nicotiana benthamiana, sirnas (determined by cloning and sequencing) predominantly originated from the sense (+) strand of the viral rna, suggesting that the majority of sirnas are produced through the direct cleavage of the viru ...	2006	16815561
efficient virus-induced gene silencing in arabidopsis.	virus-induced gene silencing (vigs) is a plant rna-silencing technique that uses viral vectors carrying a fragment of a gene of interest to generate double-stranded rna, which initiates the silencing of the target gene. several viral vectors have been developed for vigs and they have been successfully used in reverse genetics studies of a variety of processes occurring in plants. this approach has not been widely adopted for the model dicotyledonous species arabidopsis (arabidopsis thaliana), po ...	2006	16815951
bovine cd14 receptor produced in plants reduces severity of intramammary bacterial infection.	cd14 is a high-affinity receptor protein for the complex of bacterial lps (lps) and lps binding protein in animals. binding of the soluble form of cd14 (scd14) to lps, found in the outer membrane of escherichia coli and other gram-negative bacteria, enhances host innate immune responses, reduces the severity of mastitis, and facilitates clearance and neutralization of lps, thus protecting against an excessive immune response to lps and development of endotoxic shock. a truncated form of scd14, c ...	2006	16816109
development of cucumber mosaic virus as a vector modifiable for different host species to produce therapeutic proteins.	we have developed cucumber mosaic virus (cmv) as a plant virus vector especially for production of pharmaceutical proteins. the cmv vector is a vector modifiable for different host plants and does not require further engineering steps. cmv contains three genomic rna molecules (rnas 1-3) necessary for infectivity. with this system, instead of creating different vector constructs for each plant we use, we take advantage of the formation of pseudrecombinants between two cmv isolates by simply reass ...	2007	16821041
spatio-temporal accumulation of micrornas is highly coordinated in developing plant tissues.	micrornas (mirnas) are an abundant class of small, endogenous non-protein-coding rnas, approximately 21 nucleotides in length, that modulate the expression of animal and plant target genes at the post-transcriptional level. recent work has shown that mirna-based gene regulation plays a crucial role in pathways involved in plant growth and development. however, knowledge about the timing and spatial regulation of plant mirna expression is still limited. here we used in situ analysis to demonstrat ...	2006	16824182
molecular and enzymatic characterizations of novel bifunctional 3beta-hydroxysteroid dehydrogenases/c-4 decarboxylases from arabidopsis thaliana.	we have isolated two cdnas from arabidopsis thaliana encoding bifunctional 3beta-hydroxysteroid dehydrogenase/c-4 decarboxylases (3betahsd/d) involved in sterol synthesis, termed at3betahsd/d1 and at3betahsd/d2. transformation of the yeast ergosterol auxotroph erg26 mutant, which lacks 3betahsd/d activity, with the at3betahsd/d1 isoform or with at3betahsd/d2 isoform containing a c-terminal at3betahsd/d1 endoplasmic reticulum-retrieval sequence restored growth and ergosterol synthesis in erg26. a ...	2006	16835224
the arginine-rich motif of bamboo mosaic virus satellite rna-encoded p20 mediates self-interaction, intracellular targeting, and cell-to-cell movement.	satellite rna of bamboo mosaic virus (satbamv) has a single open reading frame for a nonstructural, rna-binding protein, p20, which facilitates the long-distance movement of satbamv in nicotiana benthamiana. here, we elucidate various biological properties of p20 and the involvement of a single domain in its activities. p20 displayed a strong self-interaction in vitro and in vivo, and cross-linking assays demonstrated its oligomerization. domain mapping, using the bacterial two-hybrid system, in ...	2006	16838788
corr regulates multiple components of virulence in pseudomonas syringae pv. tomato dc3000.	the phytotoxin coronatine (cor) is produced by various pathovars of pseudomonas syringae, including p. syringae pv. tomato dc3000, which is pathogenic on crucifers and tomato, and p. syringae pv. glycinea pg4180, a soybean pathogen. the cor molecule contains two distinct components, coronafacic acid (cfa) and coronamic acid (cma), which are intermediates in the cor biosynthetic pathway. in p. syringae pv. tomato dc3000, it is not clear whether corr, which encodes a response regulator, positively ...	2006	16838789
functional analysis of the five melon necrotic spot virus genome-encoded proteins.	function of the melon necrotic spot virus (mnsv) genome-encoded proteins (p29, p89, p7a, p7b and p42) has been studied. protein-expression mutants of an infectious, full-length cdna clone of a spanish mnsv-al isolate and a recombinant green fluorescent protein (gfp)-expressing virus were used in infection bioassays on melon plants. results revealed that p29 and p89 are both essential for virus replication, whereas small proteins p7a and p7b are sufficient to support viral movement between adjace ...	2006	16847133
detection of 6k1 as a mature protein of 6 kda in plum pox virus-infected nicotiana benthamiana.	the rna genome of plum pox virus (ppv) encodes one large polyprotein that is subsequently cleaved into mature viral proteins. one of the products of proteolytic processing, the 6k1 protein, has not yet been identified in vivo for any member of the genus potyvirus. in this study, 6k1-specific polyclonal antiserum was raised against ppv 6k1 expressed in escherichia coli as a translational fusion with the n terminus of avian troponin c and an unusual metal-binding cluster of troponin t-1. for detec ...	2006	16847134
barley stripe mosaic virus-encoded proteins triple-gene block 2 and gammab localize to chloroplasts in virus-infected monocot and dicot plants, revealing hitherto-unknown roles in virus replication.	replication of barley stripe mosaic virus (bsmv), genus hordeivirus, is thought to be associated with vesicles in proplastids and chloroplasts, but the molecular details of the process and identity of virus proteins involved in establishing the virus replication complexes are unknown. in addition, bsmv encodes a triple-gene block of movement proteins (tgbs) that putatively share functional roles with their counterparts in other hordei-, pomo- and pecluviruses, but detailed information on the int ...	2006	16847137
post-transcriptional gene silencing in controlling viruses of the tomato yellow leaf curl virus complex.	tomato yellow leaf curl disease (tylcd) is caused by a group of geminiviruses that belong to the tomato yellow leaf curl virus (tylcv) complex and are transmitted by the whitefly (bemisia tabaci genn.). the disease causes great yield losses in many countries throughout the mediterranean region and the middle east. in this study, the efficacy of post-transcriptional gene silencing (ptgs) to control the disease caused by tylcv complex was investigated. non-coding conserved regions from the genome ...	2006	16862387
a 38-amino-acid sequence encompassing the arm domain of the cucumber necrosis virus coat protein functions as a chloroplast transit peptide in infected plants.	experiments to determine the subcellular location of the coat protein (cp) of the tombusvirus cucumber necrosis virus (cnv) have been conducted. by confocal microscopy, it was found that an agroinfiltrated cnv cp-green fluorescent protein (gfp) fusion targets chloroplasts in nicotiana benthamiana leaves and that a 38-amino-acid (aa) region that includes the complete cp arm region plus the first 4 amino acids of the shell domain are sufficient for targeting. western blot analyses of purified and ...	2006	16873252
a viral resistance gene from common bean functions across plant families and is up-regulated in a non-virus-specific manner.	genes involved in a viral resistance response in common bean (phaseolus vulgaris cv. othello) were identified by inoculating a geminivirus reporter (bean dwarf mosaic virus expressing the green fluorescent protein), extracting rna from tissue undergoing the defense response, and amplifying sequences with degenerate r gene primers. one such gene (a tir-nbs-lrr gene, rt4-4) was selected for functional analysis in which transgenic nicotiana benthamiana were generated and screened for resistance to ...	2006	16880399
permeabilized mammalian cells as an experimental system for nuclear import of geminiviral karyophilic proteins and of synthetic peptides derived from their nuclear localization signal regions.	the plant-infecting geminiviruses deliver their genome and viral proteins into the host cell nucleus. members of the family geminiviridae possess either a bipartite genome composed of two approximately 2.6 kb dnas or a monopartite genome of approximately 3.0 kb dna. the bipartite genome of bean dwarf mosaic virus (bdmv) encodes several karyophilic proteins, among them the capsid protein (cp) and bv1 (nuclear shuttle protein). a cp is also encoded by the monopartite genome of tomato yellow leaf c ...	2006	16894212
floral patterning defects induced by arabidopsis apetala2 and microrna172 expression in nicotiana benthamiana.	floral patterning and morphogenesis are controlled by many transcription factors including floral homeotic proteins, by which floral organ identity is determined. recent studies have uncovered widespread regulation of transcription factors by micrornas (mirnas), approximately 21-nucleotide non-coding rnas that regulate protein-coding rnas through transcript cleavage and/or translational inhibition. the regulation of the floral homeotic gene apetala2 (ap2) by mir172 is crucial for normal arabidop ...	2006	16897492
propagation of plant viruses in hairy root cultures: a potential method for in vitro production of epitope vaccines and foreign proteins.	hairy roots were used as an in vitro culture system for the propagation of wild-type and transgenic plant viruses. tobacco mosaic virus (tmv) was added to the liquid culture medium at the same time as root inoculation. hairy root growth was unaffected by viral infection. maximum concentrations of tmv in nicotiana benthamiana hairy roots were 1-2 orders of magnitude greater than in suspended n. benthamiana cells and reached levels of 1-2 mg g(-1) dry weight or 20-28% total soluble protein. virus ...	2007	16900508
synergistic interactions of the plant cell death pathways induced by phytophthora infestans nepl-like protein pinpp1.1 and inf1 elicitin.	cell death plays a ubiquitous role in plant-microbe interactions, given that it is associated with both susceptible and resistance interactions. a class of cell death-inducing proteins, termed nepl-like proteins (nlps), has been reported in bacteria, fungi, and oomycetes. these proteins induce nonspecific necrosis in a variety of dicotyledonous plants. here, we describe three members of the nlp family from the oomycete phytophthora infestans (pinpp1.1, pinpp1.2, and pinpp1.3). using agroinfectio ...	2006	16903351
characterization of the recombinant forms arising from a potato virus x chimeric virus infection under rna silencing pressure.	recombination is a frequent phenomenon in rna viruses whose net result is largely influenced by selective pressures. rna silencing in plants acts as a defense mechanism against viruses and can be used to engineer virus resistance. here, we have investigated the influence of rna silencing as a selective pressure to favor recombinants of pvx-hct, a chimeric potato virus x (pvx) vector carrying the helper-component proteinase (hc-pro) gene from plum pox virus (ppv). all the plants from two lines ex ...	2006	16903356
tobacco wlim1 is a novel f-actin binding protein involved in actin cytoskeleton remodeling.	we used confocal microscopy and in vitro analyses to show that nicotiana tabacum wlim1, a lim domain protein related to animal cys-rich proteins, is a novel actin binding protein in plants. green fluorescent protein (gfp)-tagged wlim1 protein accumulated in the nucleus and cytoplasm of tobacco by2 cells. it associated predominantly with actin cytoskeleton, as demonstrated by colabeling and treatment with actin-depolymerizing latrunculin b. high-speed cosedimentation assays revealed the ability o ...	2006	16905656
down-regulation of the 26s proteasome subunit rpn9 inhibits viral systemic transport and alters plant vascular development.	plant viruses utilize the vascular system for systemic movement. the plant vascular network also transports water, photosynthates, and signaling molecules and is essential for plant growth. however, the molecular mechanisms governing vascular development and patterning are still largely unknown. from viral transport suppressor screening using virus-induced gene silencing, we identified a 26s proteasome subunit, rpn9, which is required for broad-spectrum viral systemic transport. silencing of rpn ...	2006	16905670
mitochondria-associated hexokinases play a role in the control of programmed cell death in nicotiana benthamiana.	recent findings suggest a pivotal role for mitochondria-associated hexokinase in the regulation of apoptosis in animal cells. in this study, virus-induced gene silencing (vigs) of a hexokinase-encoding hxk1 caused necrotic lesions on leaves, abnormal leaf morphology, and retarded plant growth in nicotiana benthamiana. hxk1 was associated with the mitochondria, and this association required the n-terminal membrane anchor. vigs of hxk1 reduced the cellular glucose-phosphorylating activity to appro ...	2006	16920781
vpg of potato virus a alone does not suppress rna silencing but affects virulence of a heterologous virus.	the viral genome-linked protein (vpg) is a well-known virulence factor in potyviruses (genus potyvirus), including potato virus a (pva). its ability to suppress onset and signalling of transgene-mediated rna silencing and accumulation of small interfering rna (sirna) was studied using cross-protection and agrobacterium infiltration assays and green fluorescent protein (gfp) and pva vpg protein-expressing transgenic nicotiana benthamiana plants. n. benthamiana plants were also transformed with a ...	2007	16927117
characterization of membrane association domains within the tomato ringspot nepovirus x2 protein, an endoplasmic reticulum-targeted polytopic membrane protein.	replication of nepoviruses (family comoviridae) occurs in association with endoplasmic reticulum (er)-derived membranes. we have previously shown that the putative nucleoside triphosphate-binding protein (ntb) of tomato ringspot nepovirus is an integral membrane protein with two er-targeting sequences and have suggested that it anchors the viral replication complex (vrc) to the membranes. a second highly hydrophobic protein domain (x2) is located immediately upstream of the ntb domain in the rna ...	2006	16928745
protein-protein interactions and nuclear trafficking of coat protein and betac1 protein associated with bhendi yellow vein mosaic disease.	bhendi yellow vein mosaic disease (byvmd) is caused by a complex consisting of a monopartite begomovirus byvmv and a satellite dna beta component. byvmv represents a new member of the emerging group of monopartite begomoviruses requiring a satellite component for symptom induction. here we report the results of the transient expression of green fluorescent protein (gfp) fused with the betac1 and coat protein (cp) coding regions, in the epidermal cells of nicotiana benthamiana. gfpcp was found to ...	2006	16934356
translocation of tomato bushy stunt virus p19 protein into the nucleus by aly proteins compromises its silencing suppressor activity.	the p19 protein of tomato bushy stunt virus is a potent suppressor of rna silencing and, depending on the host species, is required for short- and long-distance virus movement and symptom production. p19 interacts with plant aly proteins and relocalizes a subset of these proteins from the nucleus to the cytoplasm. here we showed that coexpression by agroinfiltration in nicotiana benthamiana of p19 and the subset of aly proteins that are not relocalized from the nucleus interfered with the abilit ...	2006	16940518
the type iii effector repertoire of pseudomonas syringae pv. syringae b728a and its role in survival and disease on host and non-host plants.	the bacterial plant pathogen pseudomonas syringae injects a large repertoire of effector proteins into plant cells using a type iii secretion apparatus. effectors can trigger or suppress defences in a host-dependent fashion. host defences are often accompanied by programmed cell death, while interference with defences is sometimes associated with cell death suppression. we previously predicted the effector repertoire of the sequenced bean pathogen p. syringae pv. syringae (psy) b728a using bioin ...	2006	16942603
encapsidation of genomic but not subgenomic turnip yellow mosaic virus rna by coat protein provided in trans.	we have studied the encapsidation requirements of turnip yellow mosaic virus (tymv) genomic and subgenomic rna using an "agroinfiltration" procedure involving transient expression of rnas and coat protein (cp) in nicotiana benthamiana leaves. although n. benthamiana is a nonhost, expression of tymv rna in its leaves by agroinfiltration resulted in efficient local infection and production of the expected virions containing genomic and subgenomic rnas together with empty capsids. a nonreplicating ...	2006	16942786
robotized thermal and chlorophyll fluorescence imaging of pepper mild mottle virus infection in nicotiana benthamiana.	after infecting a susceptible host, pathogens spread throughout the plant. depending on pathogen type and strain, the severity of symptoms varies greatly. in the case of pepper mild mottle virus (pmmov) infection in nicotiana benthamiana, newly developing leaves display visual symptoms (symptomatic leaves). in this study, two pmmov strains were used, the spanish strain (pmmov-s) being more virulent than the italian strain (pmmov-i). plants infected with pmmov-i could recover from the virus-induc ...	2006	16943218
in planta transient expression as a system for genetic and biochemical analyses of chlorophyll biosynthesis.	mg chelatase is a multi-subunit enzyme that catalyses the first committed step of chlorophyll biosynthesis. studies in higher plants and algae indicate that the mg chelatase reaction product, mg-protoporphyrin ix plays an essential role in nuclear-plastid interactions. a number of mg chelatase mutants have been isolated from higher plants, including semi-dominant alleles of chli, the gene encoding the i subunit of the enzyme. to investigate the function of higher plant chli, bacterial orthologue ...	2006	16953878