Publications

isolation and characterization of aawrky1, an artemisia annua transcription factor that regulates the amorpha-4,11-diene synthase gene, a key gene of artemisinin biosynthesis.	amorpha-4,11-diene synthase (ads) of artemisia annua catalyzes the conversion of farnesyl diphosphate into amorpha-4,11-diene, the first committed step in the biosynthesis of the antimalarial drug artemisinin. the promoters of ads contain two reverse-oriented ttgacc w-box cis-acting elements, which are the proposed binding sites of wrky transcription factors. a full-length cdna (aawrky1) was isolated from a cdna library of the glandular secretory trichomes (gsts) in which artemisinin is synthesi ...	2009	19880398
plastocyanin transit peptide interacts with potato virus x coat protein, while silencing of plastocyanin reduces coat protein accumulation in chloroplasts and symptom severity in host plants.	potato virus x coat protein (pvxcp) is, through communication with host proteins, involved in processes such as virus movement and symptom development. here, we report that pvxcp also interacts with the precursor of plastocyanin, a protein involved in photosynthesis, both in vitro and in vivo. yeast two-hybrid analysis indicated that pvxcp interacted with only the plastocyanin transit peptide. in subsequent bimolecular fluorescence complementation assays, both proteins were collocated within chl ...	2009	19888818
immunomodulatory activity of a plant extract containing human papillomavirus 16-e7 protein in human monocyte-derived dendritic cells.	this study reports the immunomodulatory activity on human monocyte derived dendritic cells (mddcs) of a vaccine preparation shown to be effective against an hpv16-related tumour in an animal model. the vaccine is composed of extract from nicotiana benthamiana leaves containing hpv16 e7 protein expressed by a potato virus x-derived vector (nbpvx-e7). the effect of the extract was evaluated on mddc differentiation and maturation by monitoring the phenotypic expression of specific markers. the resu ...	2009	20074460
evidence for alternate states of cucumber mosaic virus replicase assembly in positive- and negative-strand rna synthesis.	cucumber mosaic virus (cmv) encodes two viral replication proteins, 1a and 2a. accumulating evidence implies that different aspects of 1a-2a interaction in replication complex assembly are involved in the regulation of virus replication. to further investigate cmv replicase assembly and to dissect the involvement of replicase activities in negative- and positive-strand synthesis, we transiently expressed cmv rnas and/or proteins in nicotiana benthamiana leaves using a dna or rna-mediated express ...	2009	19022467
identification of miniature inverted-repeat transposable elements (mites) and biogenesis of their sirnas in the solanaceae: new functional implications for mites.	small rnas regulate the genome by guiding transcriptional and post-transcriptional silencing machinery to specific target sequences, including genes and transposable elements (tes). although miniature inverted-repeat transposable elements (mites) are closely associated with euchromatic genes, the broader functional impact of these short te insertions in genes is largely unknown. we identified 22 families of mites in the solanaceae (mis1-mis22) and found abundant mis insertions in solanaceae geno ...	2009	19037014
biochemical and immunological characterization of the plant-derived candidate human immunodeficiency virus type 1 mucosal vaccine ctb-mpr.	plants are potentially the most economical platforms for the large-scale production of recombinant proteins. thus, plant-based expression of subunit human immunodeficiency virus type 1 (hiv-1) vaccines provides an opportunity for their global use against the acquired immunodeficiency syndrome pandemic. ctb-mpr(649-684)[ctb, cholera toxin b subunit; mpr, membrane proximal (ectodomain) region of gp41] is an hiv-1 vaccine candidate that has been shown previously to induce antibodies that block a pa ...	2009	19037902
the p0 gene of sugarcane yellow leaf virus encodes an rna silencing suppressor with unique activities.	the sugarcane yellow leaf virus (scylv) p0, a member of the highly heterologous proteins of poleroviruses, is a suppressor of posttranscriptional gene silencing (ptgs) and has additional activities not seen in other p0 proteins. the p0 protein in previously tested poleroviruses (beet western yellows virus and cucurbit aphid-borne yellows virus), suppresses local, but not systemic, ptgs induced by both sense gfp and inverted repeat gf using its f-box-like domain to mediate destabilization of the ...	2009	19046592
diverse and newly recognized effects associated with short interfering rna binding site modifications on the tomato bushy stunt virus p19 silencing suppressor.	the tomato bushy stunt virus-encoded p19 forms dimers that bind duplex short interfering rnas (sirnas) to suppress rna silencing. p19 is also involved in multiple host-specific activities, including the elicitation of symptoms, and in local and/or systemic spread. to study the correlation between those various roles and the sirna binding by p19, predicted sirna-interacting sites were modified. twenty-two mutants were generated and inoculated onto nicotiana benthamiana plants, to reveal that (i) ...	2009	19052093
the pseudomonas syringae effector protein, avrrps4, requires in planta processing and the krvy domain to function.	a pseudomonas syringae pv. pisi effector protein, avrrps4, triggers rps4-dependent immunity in arabidopsis. we characterized biochemical and genetic aspects of avrrps4 function. secretion of avrrps4 from pst dc3000 is type iii secretion-dependent, and avrrps4 is processed into a smaller form in plant cells but not in bacteria or yeast. agrobacterium-mediated transient expression analysis of n-terminally truncated avrrps4 mutants revealed that the c-terminal 88 amino acids are sufficient to trigg ...	2009	19054367
curtovirus-cucurbit interaction: acquisition host plays a role in leafhopper transmission in a host-dependent manner.	curly top disease (ctd) of vegetable crops is caused by viruses in the genus curtovirus (family geminiviridae). cucurbits are reported to be susceptible to ctd; however, the disease is rare in california despite annual outbreaks in other hosts (e.g., common bean, pepper, sugar beet, and tomato). consistent with these observations, no obvious curly top symptoms were observed in melon fields surveyed for ctd in central california in 2004 and 2005, whereas the disease was readily observed in tomato ...	2009	19055441
a critical domain of the cucumber mosaic virus 2b protein for rna silencing suppressor activity.	alignment of cucumber mosaic virus (cmv) 2b protein sequences from two cmv subgroups revealed two highly variable regions. to examine contributions of variable sequence domains to the suppressor activity, we performed a comparative study between 2b proteins of a subgroup i strain (sd-cmv) and a subgroup ii strain (q-cmv). here we show that the suppressor activity of sd2b is stronger than that of q2b and that a domain existent in sd2b but absent in q2b is a major determinant of the suppressor act ...	2009	19059248
production of cucumber mosaic virus rna5 and its role in recombination.	cucumber mosaic virus (cmv) is a plant infecting tripartite positive-strand rna virus. in addition to three genomic and two known subgenomic rnas, cmv strains of subgroup ii (e.g. q-cmv), but not subgroup i (e.g. fny-cmv), produce and package a redundant rna5 encompassing the 3' 304-307 nucleotides of rnas 2 and 3. the mechanism regulating rna5 production and its role in cmv life cycle is unknown. in this study, transient expression of q2 or q3 by agroinfiltration into nicotiana benthamiana plan ...	2009	19059620
ay-wb phytoplasma secretes a protein that targets plant cell nuclei.	the fully sequenced genome of aster yellows phytoplasma strain witches' broom (ay-wb; candidatus phytoplasma asteris) was mined for the presence of genes encoding secreted proteins based on the presence of n-terminal signal peptides (sp). we identified 56 secreted ay-wb proteins (sap). these sap are candidate effector proteins potentially involved in interaction with plant and insect cell components. one of these sap, sap11, contains an n-terminal sp sequence and a eukaryotic bipartite nuclear l ...	2009	19061399
serine palmitoyltransferase, the first step enzyme in sphingolipid biosynthesis, is involved in nonhost resistance.	an overexpression screen of nicotiana benthamiana cdnas identified a gene for the lcb2 subunit of serine palmitoyltransferase (spt) as a potent inducer of hypersensitive response-like cell death. the pyridoxal 5'-phosphate binding site of nblcb2 is required for its function as a cell death inducer. nblcb2 mrna is accumulated after infection by nonhost pathogen pseudomonas cichorii. resistance of n. benthamiana against p. cichorii was compromised by treatment with an spt inhibitor and in nblcb2- ...	2009	19061400
tandem leader proteases of grapevine leafroll-associated virus-2: host-specific functions in the infection cycle.	several viruses in the genus closterovirus including grapevine leafroll-associated virus-2 (glrav-2), encode a tandem of papain-like leader proteases (l1 and l2) whose functional profiles remained largely uncharacterized. we generated a series of the full-length, reporter-tagged, clones of glrav-2 and demonstrated that they are systemically infectious upon agroinfection of an experimental host plant nicotiana benthamiana. these clones and corresponding minireplicon derivatives were used to addre ...	2009	19007962
leaf proteome analysis of transgenic plants expressing antiviral antibodies.	the expression of exogenous antibodies in plant is an effective strategy to confer protection against viral infection or to produce molecules with pharmaceutical interest. however, the acceptance of the transgenic technology to obtain self-protecting plants depends on the assessment of their substantial equivalence compared to non-modified crops with an established history of safe use. in fact, the possibility exists that the introduction of transgenes in plants may alter expression of endogenou ...	2009	19099506
the lcb2 subunit of the sphingolip biosynthesis enzyme serine palmitoyltransferase can function as an attenuator of the hypersensitive response and bax-induced cell death.	previous results showed that expression of the gene encoding the long-chain base2 (lcb(2)) subunit of serine palmitoyltransferase (spt), designated bclcb(2), from nonheading chinese cabbage (brassica campestris ssp. chinensis) was up-regulated during hypersensitive cell death (hcd) induced by the phytophthora boehmeriae elicitor pb90. overexpression of bclcb(2) in nicotiana tabacum leaves suppressed the hcd normally initiated by elicitors and pb90-triggered h(2)o(2) accumulation. bclcb(2) also f ...	2009	19076721
grapevine virusa-mediated gene silencing in nicotiana benthamiana and vitis vinifera.	virus-induced gene silencing (vigs) is an attractive approach for studying gene function. although the number of virus vectors available for use in vigs experiments has increased in recent years, most of these vectors are applied in annual or herbaceous plants. the aim of this work was to develop a vigs vector based on the grapevine virus a (gva), which is a member of the genus vitivirus, family flexiviridae. the gva vector was used to silence the endogenous phytoene desaturase (pds) gene in nic ...	2009	19010356
the colletotrichum orbiculare ssd1 mutant enhances nicotiana benthamiana basal resistance by activating a mitogen-activated protein kinase pathway.	plant basal resistance is activated by virulent pathogens in susceptible host plants. a colletotrichum orbiculare fungal mutant defective in the ssd1 gene, which regulates cell wall composition, is restricted by host basal resistance responses. here, we identified the nicotiana benthamiana signaling pathway involved in basal resistance by silencing the defense-related genes required for restricting the growth of the c. orbiculare mutant. only silencing of map kinase kinase2 or of both salicylic ...	2009	19706796
regions of the cf-9b disease resistance protein able to cause spontaneous necrosis in nicotiana benthamiana lie within the region controlling pathogen recognition in tomato.	the tomato cf-9 and cf-9b genes both confer resistance to the leaf mold fungus cladosporium fulvum but only cf-9 confers seedling resistance and recognizes the avirulence (avr) protein avr9 produced by c. fulvum. using domain swaps, leucine-rich repeats (lrr) 5 to 15 of cf-9 were shown to be required for cf-9-specific resistance to c. fulvum in tomato, and the entire n-terminus up to lrr15 of cf-9b was shown to be required for cf-9b-specific resistance. finer domain swaps showed that nine amino- ...	2009	19737095
rnai-mediated transgenic tospovirus resistance broken by intraspecies silencing suppressor protein complementation.	extension of an inverted repeat transgene cassette, containing partial nucleoprotein (n) gene sequences from four different tomato-infecting tospovirus spp. with a partial n gene sequence from the tomato strain of tomato yellow ring virus (tyrv-t), renders transgenic nicotiana benthamiana plants additionally resistant to this strain but not to the soybean strain of this tospovirus sp. (tyrv-s), both strains exhibiting 14.4% nucleotide sequence divergence in their n genes. surprisingly, coinocula ...	2009	19737098
complementation analysis of triple gene block of potato virus s (pvs) revealed its capability to support systemic infection and aphid transmissibility of recombinant potato virus x.	triple gene block (tgb) sequences derived from isolates of ordinary potato virus s (pvs-o) and chenopodium-systemic (pvs-cs) were analyzed. although the tgb sequences did not reveal any specific difference within the 7k protein, some specific differences within the 25k and 12k orfs were found. in order to investigate a possible functional divergence of pvs-o and pvs-cs tgb variants, these genes were propagated in chimeric potato virus x (pvx). both pvs tgb variants partly complemented pvx tgb in ...	2009	19748533
molecular characterization and experimental host range of an isolate of wissadula golden mosaic st. thomas virus.	partial genome segments of a begomovirus were previously amplified from wissadula amplissima exhibiting yellow-mosaic and leaf-curl symptoms in the parish of st. thomas, jamaica and this isolate assigned to a tentative begomovirus species, wissadula golden mosaic st. thomas virus. to clone the complete genome of this isolate of wissadula golden mosaic st. thomas virus, abutting primers were designed to pcr amplify its full-length dna-a and dna-b components. sequence analysis of the complete bego ...	2009	19768650
production and characterization of an orally immunogenic plasmodium antigen in plants using a virus-based expression system.	increasing numbers of plant-made vaccines and pharmaceuticals are entering the late stage of product development and commercialization. despite the theoretical benefits of such production, expression of parasite antigens in plants, particularly those from plasmodium, the causative parasites for malaria, have achieved only limited success. we have previously shown that stable transformation of tobacco plants with a plant-codon optimized form of the plasmodium yoelii merozoite surface protein 4/5 ...	2009	19781007
expression of hemagglutinin-neuraminidase glycoprotein of newcastle disease virus in agroinfiltrated nicotiana benthamiana plants.	the worldwide need for producing safer and less expensive vaccines with minor manufacture and processing requirements, together with the advances made through biotechnology, has promoted the development of efficient alternative tools to conventional vaccines. one of these is the use of plants or plant cell culture as production platforms of vaccine antigens with potential use as immunogens. we have already described the use of transgenic potato plants as immunogens against newcastle disease viru ...	2009	19799942
[new role for tobacco--production of biopharmaceuticals].	over one hundred of biopharmaceuticals present on the pharmaceutical market--among them mainly therapeutically peptides and proteins such as hormones, enzymes, interferons, blood factors, monoclonal antibodies, vaccines, growth factors and fusion proteins, are manufactured through recombinant dna technology in cultures of transgenic bacterial (escherichia coli), yeast (saccharomyces cerevisiae) and mammalian cells (cho, bhk) and rarely insect cells or insects (bombyx mori). high costs of their m ...	2009	20301965
production of biologically active human myelocytokines in plants.	an effective system for expression of human granulocyte and granulocyte macrophage colony-stimulating factors (hg-csf and hgm-csf) in nicotiana benthamiana plants was developed using viral vector based on tobacco mosaic virus infecting cruciferous plants. the genes of target proteins were cloned into the viral vector driven by actin promoter of arabidopsis thaliana. the expression vectors were delivered into plant cells by agroinjection. maximal synthesis rate was detected 5 days after injection ...	2009	19916932
high-level hiv-1 nef transient expression in nicotiana benthamiana using the p19 gene silencing suppressor protein of artichoke mottled crinckle virus.	in recent years, different hiv antigens have been successfully expressed in plants by either stable transformation or transient expression systems. among hiv proteins, nef is considered a promising target for the formulation of a multi-component vaccine due to its implication in the first steps of viral infection. attempts to express nef as a single protein product (not fused to a stabilizing protein) in transgenic plants resulted in disappointingly low yields (about 0.5% of total soluble protei ...	2009	19930574
myosin xi is required for actin-associated movement of plastid stromules.	stromules are highly dynamic stroma-filled tubules extending from the surface of plastids and occasionally interconnecting individual plastids, allowing the movement of complex biological molecules between the interconnected plastids. experiments with inhibitors of cytoskeleton assembly have indicated the involvement of an actin-based system in stromule movement. however, the motor protein associated with the system had not been identified. here, we present direct evidence that myosin xi is invo ...	2009	19995729
a myosin xi tail domain homologous to the yeast myosin vacuole-binding domain interacts with plastids and stromules in nicotiana benthamiana.	the actin cytoskeleton plays a role in mobility of many different organelles in plant cells, including chloroplasts, mitochondria, golgi, and peroxisomes. while progress has been made in identifying the myosin motors involved in trafficking of various plant organelles, not all of the cargoes mobilized by different members of the myosin xi family have yet been identified. the involvement of myosins in chloroplast positioning and mitochondrial movement was demonstrated by expression of a virus-ind ...	2009	19995734
synergism and negative interference during co-infection of tomato and nicotiana benthamiana with two bipartite begomoviruses.	in brazil, at least eight begomoviruses including tomato rugose mosaic virus (tormv) and tomato yellow spot virus (toysv) infect tomatoes. toysv symptoms in tomato and nicotiana benthamiana appear earlier and are more severe compared to those of tormv. we investigated the role of several factors in this differential adaptation. to analyze infection kinetics, a single leaf was inoculated and subsequently detached after different periods of time. viral dna accumulation was quantified in plants, vi ...	2009	19282016
identification of an arabidopsis unknown small membrane protein targeted to mitochondria, chloroplasts, and peroxisomes.	in a functional genomic screen performed by combining an arabidopsis-yellow fluorescent protein (yfp)-fused complementary dna (cdna) library, rat fibroblasts as host and automatic microscopy, we found a short protein with a predictable trans-membrane domain encoded on chromosome 2. in rat fibroblasts, its pattern of distribution was to various organelle-like structures. from the databases, we learned that it has another family member in arabidopsis and homologs in several other plants, chlamydom ...	2009	19283443
suppression of bamboo mosaic virus accumulation by a putative methyltransferase in nicotiana benthamiana.	bamboo mosaic virus (bamv) is a 6.4-kb positive-sense rna virus belonging to the genus potexvirus of the family flexiviridae. the 155-kda viral replicase, the product of orf1, comprises an n-terminal s-adenosyl-l-methionine (adomet)-dependent guanylyltransferase, a nucleoside triphosphatase/rna 5'-triphosphatase, and a c-terminal rna-dependent rna polymerase (rdrp). to search for cellular factors potentially involved in the regulation of replication and/or transcription of bamv, the viral rdrp d ...	2009	19297487
plant-produced human growth hormone shows biological activity in a rat model.	plants have been shown to be efficient systems for expressing a wide range of recombinant proteins from various origins. here, using a plant virus-based expression vector to produce human growth hormone (hgh) in nicotiana benthamiana plants, we demonstrate, for the first time, that the plant-produced hgh (pphgh) is biologically active in a hypophysectomized rat model. we observed an average weight gain of approximately 17 g per animal in a group of 10 animals that were injected subcutaneously wi ...	2009	19301254
plant-derived recombinant f1, v, and f1-v fusion antigens of yersinia pestis activate human cells of the innate and adaptive immune system.	plague is still endemic in different regions of the world. current vaccines raise concern for their side effects and limited protection, highlighting the need for an efficacious and rapidly producible vaccine. f1 and v antigens of yersinia pestis, and f1-v fusion protein produced in nicotiana benthamiana administered to guinea pigs resulted in immunity and protection against an aerosol challenge of virulent y. pestis. we examined the effects of plant-derived f1, v, and f1-v on human cells of the ...	2009	19309560
a dna replicon system for rapid high-level production of virus-like particles in plants.	recombinant virus-like particles (vlps) represent a safe and effective vaccine strategy. we previously described a stable transgenic plant system for inexpensive production and oral delivery of vlp vaccines. however, the relatively low-level antigen accumulation and long-time frame to produce transgenic plants are the two major roadblocks in the practical development of plant-based vlp production. in this article, we describe the optimization of geminivirus-derived dna replicon vectors for rapid ...	2009	19309755
a unique virulence factor for proliferation and dwarfism in plants identified from a phytopathogenic bacterium.	one of the most important themes in agricultural science is the identification of virulence factors involved in plant disease. here, we show that a single virulence factor, tengu-su inducer (tengu), induces witches' broom and dwarfism and is a small secreted protein of the plant-pathogenic bacterium, phytoplasma. when tengu was expressed in nicotiana benthamiana plants, these plants showed symptoms of witches' broom and dwarfism, which are typical of phytoplasma infection. transgenic arabidopsis ...	2009	19329488
scaleable manufacture of hiv-1 entry inhibitor griffithsin and validation of its safety and efficacy as a topical microbicide component.	to prevent sexually transmitted hiv, the most desirable active ingredients of microbicides are antiretrovirals (arvs) that directly target viral entry and avert infection at mucosal surfaces. however, most promising arv entry inhibitors are biologicals, which are costly to manufacture and deliver to resource-poor areas where effective microbicides are urgently needed. here, we report a manufacturing breakthrough for griffithsin (grft), one of the most potent hiv entry inhibitors. this red algal ...	2009	19332801
cymbidium mosaic potexvirus isolate-dependent host movement systems reveal two movement control determinants and the coat protein is the dominant.	little is known about how plant viruses of a single species exhibit different movement behavior in different host species. two cymbidium mosaic potexvirus (cymmv) isolates, m1 and m2, were studied. both can infect phalaenopsis orchids, but only m1 can systemically infect nicotiana benthamiana plants. protoplast inoculation and whole-mount in situ hybridization revealed that both isolates can replicate in n. benthamiana; however, m2 was restricted to the initially infected cells. genome shuffling ...	2009	19345971
analysis of temperature modulation of plant defense against biotrophic microbes.	plant-pathogen interactions are known to be affected by environmental factors including temperature; however, the temperature effects have not been systematically studied in plant disease resistance. here, we characterized the effects of a moderate increase in temperature on resistance to bacterial pathogen pseudomonas syringae and two viral elicitors in arabidopsis thaliana and nicotiana benthamiana. both the basal and the resistance (r) gene-mediated defense responses to pseudomonas syringae a ...	2009	19348568
a comparative study of the involvement of 17 arabidopsis myosin family members on the motility of golgi and other organelles.	gene families with multiple members are predicted to have individuals with overlapping functions. we examined all of the arabidopsis (arabidopsis thaliana) myosin family members for their involvement in golgi and other organelle motility. truncated fragments of all 17 annotated arabidopsis myosins containing either the iq tail or tail domains only were fused to fluorescent markers and coexpressed with a golgi marker in two different plants. we tracked and calculated golgi body displacement rate ...	2009	19369591
studies of the role and function of barley stripe mosaic virus encoded proteins in replication and movement using gfp fusions.	this chapter describes techniques to investigate the localisation and function of virus-encoded proteins in plants using green fluorescent protein (gfp) transiently expressed from plasmids or infectious cdna reporter clones of barley stripe mosaic virus. virus movement and the localisation of gfp-tagged proteins in living cells were monitored by confocal laser scanning microscopy (clsm). in addition, gfp expression was imaged in transgenic plants where specific organelles or subcellular structur ...	2009	19378124
deletions in the repertoire of pseudomonas syringae pv. tomato dc3000 type iii secretion effector genes reveal functional overlap among effectors.	the gamma-proteobacterial plant pathogen pseudomonas syringae pv. tomato dc3000 uses the type iii secretion system to inject ca. 28 avr/hop effector proteins into plants, which enables the bacterium to grow from low inoculum levels to produce bacterial speck symptoms in tomato, arabidopsis thaliana, and (when lacking hopq1-1) nicotiana benthamiana. the effectors are collectively essential but individually dispensable for the ability of the bacteria to defeat defenses, grow, and produce symptoms ...	2009	19381254
a severe symptom phenotype in tomato in mali is caused by a reassortant between a novel recombinant begomovirus (tomato yellow leaf curl mali virus) and a betasatellite.	tomato production in west africa has been severely affected by begomovirus diseases, including yellow leaf curl and a severe symptom phenotype, characterized by extremely stunted and distorted growth and small deformed leaves. here, a novel recombinant begomovirus from mali, tomato yellow leaf curl mali virus (tylcmlv), is described that, alone, causes tomato yellow leaf curl disease or, in combination with a betasatellite, causes the severe symptom phenotype. tylcmlv is an old world monopartite ...	2009	19400843
synergistic interaction between the potyvirus, turnip mosaic virus and the crinivirus, lettuce infectious yellows virus in plants and protoplasts.	lettuce infectious yellows virus (liyv), the type member of the genus crinivirus in the family closteroviridae, is specifically transmitted by the sweet potato whitefly (bemisia tabaci) in a semipersistent manner. liyv infections result in a low virus titer in plants and protoplasts, impeding reverse genetic efforts to analyze liyv gene/protein functions. we found that synergistic interactions occurred in mixed infections of liyv and turnip mosaic virus (tumv) in nicotiana benthamiana plants, an ...	2009	19409943
gene silencing and virus resistance based on defective interfering constructs in transgenic nicotiana benthamiana is not linked to accumulation of sirna.	rna interference (rnai) was established in nicotiana benthamiana plants by introducing constructs containing a defective interfering (di) sequence from tomato bushy stunt virus (tbsv) in combination with a conserved sense-sequence from the target grapevine fanleaf virus (gflv). silencing in plants was confirmed by agrobacterium-mediated infiltration of a gfp-sensor containing the gflv-derived target sequence. the transgene-induced rnai led to silencing of the gfp-sensor and gfp fluorescence was ...	2009	19419883
transient co-expression for fast and high-yield production of antibodies with human-like n-glycans in plants.	plant-based transient expression is potentially the most rapid and cost-efficient system for the production of recombinant pharmaceutical proteins, but safety concerns associated with plant-specific n-glycosylation have hampered its adoption as a commercial production system. in this article, we describe an approach based on the simultaneous transient co-expression of an antibody, a suppressor of silencing and a chimaeric human beta1,4-galactosyltransferase targeted for optimal activity to the e ...	2009	19422604
impact of a defective rna 3 from cucumber mosaic virus on helper virus infection dynamics.	d rna 3yalpha (d3yalpha), a defective (d) rna 3 derived from the y strain of cucumber mosaic virus (cmv-y), was further characterized in combination with different helper viruses in the genus cucumovirus. interestingly, nicotiana benthamiana plants inoculated with cmv-d8 and d3yalpha developed systemic symptoms which were different from those induced by cmv-d8. to elucidate the potential effects of d rna 3 on virus infection on the basis of the original combination of cmv-y and d3yalpha, a point ...	2009	19427011
characterization of vitis vinifera npr1 homologs involved in the regulation of pathogenesis-related gene expression.	grapevine protection against diseases needs alternative strategies to the use of phytochemicals, implying a thorough knowledge of innate defense mechanisms. however, signalling pathways and regulatory elements leading to induction of defense responses have yet to be characterized in this species. in order to study defense response signalling to pathogens in vitis vinifera, we took advantage of its recently completed genome sequence to characterize two putative orthologs of npr1, a key player in ...	2009	19432948
evidence that the linker between the methyltransferase and helicase domains of potato virus x replicase is involved in homologous rna recombination.	recombination in rna viruses, one of the main factors contributing to their genetic variability and evolution, is a widespread phenomenon. in this study, an in vivo assay to characterize rna recombination in potato virus x (pvx), under high selection pressure, was established. agrobacterium tumefaciens was used to express in nicotiana benthamiana leaf tissue both a pvx isolate labeled with green fluorescent protein (gfp) containing a coat protein deletion mutation (deltacp) and a transcript enco ...	2009	19439477
identification and functional characterization of regions that can be crosslinked to rna in the helicase-like domain of bamv replicase.	the helicase-like domain of the bamboo mosaic virus replicase catalyzes the release of 5'-gamma-phosphate from both atp and 5'-triphosphated rna by an identical set of catalytic residues with a presumably larger binding pocket for rna. in this study, the peptidyl regions involved in rna binding were mapped by reversible formaldehyde crosslinking and mass spectrometry. eleven residues within these regions were examined by mutational analysis. h636a, y704a, and k706a greatly diminished the enzymat ...	2009	19443005
nitric oxide as a partner of reactive oxygen species participates in disease resistance to nectrotophic pathogen botryis cinerea in nicotiana benthamiana.	nitric oxide (no) is an essential regulatory molecule in plant immunity in synergy with reactive oxygen species (ros). however, little is known about the role of no in disease resistance to necrotrophic pathogens. no and oxidative bursts were induced during necrotrophic fungal pathogen botrytis cinerea and nicotiana benthamiana compatible interaction. histochemical analyses showed that both no and ros were produced in adjacent cells of invaded areas in n. benthamiana leaves. activation of salicy ...	2009	19445587
the xanthomonas campestris pv. vesicatoria type iii effector protein xopj inhibits protein secretion: evidence for interference with cell wall-associated defense responses.	the phytopathogenic bacterium xanthomonas campestris pv. vesicatoria uses the type iii secretion system (t3ss) to inject effector proteins into cells of its solanaceous host plants. it is generally assumed that these effectors manipulate host pathways to favor bacterial replication and survival. however, the molecular mechanisms by which type iii effectors suppress host defense responses are far from being understood. based on sequence similarity, xanthomonas outer protein j (xopj) is a member o ...	2009	19445590
trans-replication of, and competition between, dna beta satellites in plants inoculated with tomato yellow leaf curl china virus and tobacco curly shoot virus.	tomato yellow leaf curl china virus (tylccnv) y10 isolate (y10) and tobacco curly shoot virus (tbcsv) y35 isolate (y35), both obtained from yunnan province, were each found to be associated with a distinct species of satellite dna (dna beta). here, we demonstrate that both y10 dna beta (y10beta) and y35 dna beta (y35beta) were stably trans-replicated by the noncognate begomovirus, although the noncognate dna beta accumulated in plants at a lower level than did the cognate dna beta. in nicotiana ...	2009	19453231
functional redundancy in the arabidopsis cathepsin b gene family contributes to basal defence, the hypersensitive response and senescence.	cysteine proteases are required for programmed cell death (pcd) in animals. recent work in nicotiana benthamiana has implicated cathepsin b-like cysteine proteases in the hypersensitive response (hr) in plants, a form of pcd involved in disease resistance. here, we investigate the function and regulation of cathepsin b (cathb) genes in plant defence, and in both pathogen-inducible and developmental forms of pcd. single, double and triple knockout mutants were isolated for the three arabidopsis t ...	2009	19453434
the role of respiratory burst oxidase homologues in elicitor-induced stomatal closure and hypersensitive response in nicotiana benthamiana.	active oxygen species (aos) are central components of the defence reactions of plants against pathogens. plant respiratory burst oxidase homologues (rboh) of gp91(phox), a plasma membrane protein of the neutrophil nicotinamide adenine dinucleotide phosphate (nadph) oxidase, play a prominent role in aos production. the role of two rboh from nicotiana benthamiana, nbrboha and nbrbohb that encode plant nadph oxidase in the process of elicitor-induced stomatal closure and hypersensitive cell death i ...	2009	19454596
fluorometric quantification of green fluorescent protein in tobacco leaf extracts.	the main use of green fluorescent protein (gfp) is as a reporter system, where the existence of the protein is usually determined visually using fluorescent microscopy. although fluorescence-based quantification of gfp is possible, background fluorescence in plants and in plant extracts was observed by our group. another phenomenon we observed that makes quantification difficult is the increased level of gfp fluorescence in nicotiana benthamiana leaf extracts, probably the result of dimerization ...	2009	19457429
three c-terminal phosphorylation sites in the abutilon mosaic virus movement protein affect symptom development and viral dna accumulation.	the abutilon mosaic virus (abmv, geminiviridae) dna b component encodes a movement protein (mp), which facilitates viral transport within plants and affects pathogenicity. the presence of phosphorylated serine and threonine residues was confirmed for mp expressed in yeast and nicotiana benthamiana by comparative western blot analysis using phospho-amino acid- and mp-specific immunodetection. mass spectrometry of yeast-derived mp identified three phosphorylation sites located in the c-terminal do ...	2009	19464722
overexpression of citrus junos mitochondrial citrate synthase gene in nicotiana benthamiana confers aluminum tolerance.	aluminum (al) toxicity is one of the major factors that limit plant growth in acid soils. al-induced release of organic acids into rhizosphere from the root apex has been identified as a major al-tolerance mechanism in many plant species. in this study, al tolerance of yuzu (citrus junos sieb. ex tanaka) was tested on the basis of root elongation and the results demonstrated that yuzu was al tolerant compared with other plant species. exposure to al triggered the exudation of citrate from the yu ...	2009	19466450
the multiplicity of infection of a plant virus varies during colonization of its eukaryotic host.	the multiplicity of infection (moi), i.e., the number of virus genomes that infect a cell, is a key parameter in virus evolution, as it determines processes such as genetic exchange among genomes, selection intensity on viral genes, epistatic interactions, and the evolution of multipartite viruses. in fact, the moi level is equivalent to the virus ploidy during genome expression. nevertheless, there are few experimental estimates of moi, particularly for viruses with eukaryotic hosts. here we es ...	2009	19474097
effects of dicer-like endoribonucleases 2 and 4 on infection of arabidopsis thaliana by cucumber mosaic virus and a mutant virus lacking the 2b counter-defence protein gene.	in tobacco and nicotiana benthamiana, limited cross-protection against cucumber mosaic virus strain fny (fny-cmv) was provided by prior inoculation with a deletion mutant lacking the 2b silencing-suppressor protein gene (fny-cmvdelta2b). cross-protection by fny-cmvdelta2b did not result from induction of systemic rna silencing. we investigated whether protection occurs through induction of localized rna silencing by using arabidopsis thaliana plants harbouring mutations in genes encoding the dic ...	2009	19474248
rna binding by the brome mosaic virus capsid protein and the regulation of viral rna accumulation.	viral capsid proteins (cps) can regulate gene expression and encapsulate viral rnas. low-level expression of the brome mosaic virus (bmv) cp was found to stimulate viral rna accumulation, while higher levels inhibited translation and bmv rna replication. regulation of translation acts through an rna element named the b box, which is also critical for the replicase assembly. the bmv cp has also been shown to preferentially bind to an rna element named slc that contains the core promoter for genom ...	2009	19481091
identification of domains of the tomato spotted wilt virus nsm protein involved in tubule formation, movement and symptomatology.	deletion and alanine-substitution mutants of the tomato spotted wilt virus nsm protein were generated to identify domains involved in tubule formation, movement and symptomatology using a heterologous tobacco mosaic virus expression system. two regions of nsm, g(19)-s(159) and g(209)-v(283), were required for both tubule formation in protoplasts and cell-to-cell movement in plants, indicating a correlation between these activities. three amino acid groups, d(154), eykk(205-208) and eeeee(284-288 ...	2009	19481775
optimization of the bioprocessing conditions for scale-up of transient production of a heterologous protein in plants using a chemically inducible viral amplicon expression system.	use of transient expression for the rapid, large-scale production of recombinant proteins in plants requires optimization of existing methods to facilitate scale-up of the process. we have demonstrated that the techniques used for agroinfiltration and induction greatly impact transient production levels of heterologous protein. a cucumber mosaic virus inducible viral amplicon (cmviva) expression system was used to transiently produce recombinant alpha-1-antitrypsin (raat) by co-infiltrating harv ...	2009	19504593
virus-induced gene silencing (vigs) in nicotiana benthamiana and tomato.	rna interference (rnai) is a highly specific gene-silencing phenomenon triggered by dsrna. this silencing mechanism uses two major classes of rna regulators: micrornas, which are produced from non-protein coding genes and short interfering rnas (sirnas). plants use rnai to control transposons and to exert tight control over developmental processes such as flower organ formation and leaf development. plants also use rnai to defend themselves against infection by viruses. consequently, many viruse ...	2009	19516240
selective binding of glutathione conjugates of fatty acid derivatives by plant glutathione transferases.	proteomic studies with arabidopsis thaliana have revealed that the plant-specific tau (u) class glutathione transferases (gsts) are selectively retained by s-hexylglutathione affinity supports. overexpression of members of the arabidopsis gst superfamily in escherichia coli showed that 25 of the complement of 28 gstus caused the aberrant accumulation of acylated glutathione thioesters in vivo, a perturbation that was not observed with other gst classes. each gstu caused a specific group of fatty ...	2009	19520850
boosted expression of the sars-cov nucleocapsid protein in tobacco and its immunogenicity in mice.	vaccines produced in plant systems are safe and economical; however, the extensive application of plant-based vaccines is mainly hindered by low expression levels of heterologous proteins in plant systems. here, we demonstrated that the post-transcriptional gene silencing suppressor p19 protein from tomato bushy stunt virus substantially enhanced the transient expression of recombinant sars-cov nucleocapsid (rn) protein in nicotiana benthamiana. the rn protein in the agrobacteria-infiltrated pla ...	2009	19523911
differential requirement of ribosomal protein s6 by plant rna viruses with different translation initiation strategies.	potyvirus infection has been reported to cause an increase in the mrna transcripts of many plant ribosomal proteins (r-proteins). in this study, increased expression of r-protein mrna transcripts was determined to occur in nicotiana benthamiana during infection by potyviruses as well as a tobamovirus demonstrating that this response is not unique to potyviruses. five r-protein genes, rps6, rpl19, rpl13, rpl7, and rps2, were silenced in n. benthamiana to test their roles in viral infection. the a ...	2009	19524993
a novel cation-dependent o-methyltransferase involved in anthocyanin methylation in grapevine.	anthocyanins are major pigments in colored grape (vitis vinifera) berries, and most of them are monomethoxylated or dimethoxylated. we report here the functional characterization of an anthocyanin o-methyltransferase (aomt) from grapevine. the expression pattern in two cultivars with different anthocyanin methylation profiles (syrah and nebbiolo) showed a peak at start ripening (véraison), when the concentrations of all methylated anthocyanins begin to increase. the purified recombinant aomt pro ...	2009	19525322
cucurbit yellow stunting disorder virus p25 is a suppressor of post-transcriptional gene silencing.	post-transcriptional gene silencing (ptgs) degrades rna in a sequence-specific manner and is utilised by plants as a natural defence mechanism against virus invaders. two members of the genus crinivirus have been reported to encode suppressors and counter ptgs: sweet potato chlorotic stunt virus p22 and tomato chlorosis virus (tocv) p22, coat protein and coat protein minor. using an agrobacterium-mediated transient assay on nicotiana benthamiana wildtype and 16c plants, we screened four cucurbit ...	2009	19540278
suppression of local rna silencing is not sufficient to promote cell-to-cell movement of turnip crinkle virus in nicotiana benthamiana.	the biological relationship between suppression of rna silencing and virus movement poses an intriguing question in virus-plant interactions. here, we have used a local rna silencing assay, based on a movement-deficient turnip crinkle virus tcv/gfpdeltacp, to investigate the influence of silencing suppression by three different viral suppressors: the tcv 38k coat protein (cp), the 126k protein of tobacco mosaic virus (tmv), and p19 of tomato bushy stunt virus (tbsv) on cell-to-cell movement and ...	2009	19568335
a branched-chain aminotransferase may regulate hormone levels by affecting knox genes in plants.	branched-chain amino acid transaminases (bcats) play a crucial role in the metabolic pathway of leucine, isoleucine and valine by catalyzing the last step of synthesis and/or the initial step of degradation of these amino acids. in this study, we characterized a new bcat from nicotiana benthamiana (nbbcat, genebank accession no. eu194916), the deduced amino acid sequence of which exhibits a very high percentage of identity to the homologous enzymes from solanum tuberosum (stbcat-2, 91.5%) and ar ...	2009	19568767
maintenance of an old world betasatellite by a new world helper begomovirus and possible rapid adaptation of the betasatellite.	begomoviruses (family geminiviridae) cause major losses to crops throughout the tropical regions of the world. begomoviruses originating from the new world (nw) and the old world (ow) are genetically distinct. whereas the majority of ow begomoviruses have monopartite genomes and whereas most of these associate with a class of symptom-modulating satellites (known as betasatellites), the genomes of nw begomoviruses are exclusively bipartite and do not associate with satellites. here, we show for t ...	2009	19570867
subcellular localization of the barley stripe mosaic virus triple gene block proteins.	barley stripe mosaic virus (bsmv) spreads from cell to cell through the coordinated actions of three triple gene block (tgb) proteins (tgb1, tgb2, and tgb3) arranged in overlapping open reading frames (orfs). our previous studies (d. m. lawrence and a. o. jackson, j. virol. 75:8712-8723, 2001; d. m. lawrence and a. o. jackson, mol. plant pathol. 2:65-75, 2001) have shown that each of these proteins is required for cell-to-cell movement in monocot and dicot hosts. we recently found (h.-s. lim, j. ...	2009	19570874
interaction of tomato yellow leaf curl virus with diverse betasatellites enhances symptom severity.	the complete nucleotide sequence was determined for a begomovirus isolated from tomato exhibiting leaf curling and yellowing symptoms in tochigi prefecture in japan. the genome organization of this virus was similar to those of other old world monopartite begomoviruses. neither a dna betasatellite nor a dna-b component was detected. it had the highest total nucleotide sequence identity (99%) with tomato yellow leaf curl virus-israel[japan:tosa:2005] (tylcv-il[jr:tos:05]) and tylcv-israel[japan:h ...	2009	19575277
identification of beet necrotic yellow vein virus p25 pathogenicity factor-interacting sugar beet proteins that represent putative virus targets or components of plant resistance.	beet necrotic yellow vein virus (bnyvv) induces the most important disease threatening sugar beet. the growth of partially resistant hybrids carrying monogenic dominant resistance genes stabilize yield but are unable to entirely prevent virus infection and replication. p25 is responsible for symptom development and previous studies have shown that recently occurring resistance-breaking isolates possess increased p25 variability. to better understand the viral pathogenicity factor's interplay wit ...	2009	19589075
molecular characterization and pathogenicity of tomato yellow leaf curl virus in china.	several tomato production regions in china were surveyed for tomato yellow leaf curl disease (tylcd), and 31 tomato leaf samples showing tylcd-like symptoms were collected. the partial or full-length genomes of these isolates were sequenced and tomato yellow leaf curl virus (tylcv) was detected in shanghai, zhejiang, jiangsu shandong and hebei provinces of china. the tylcv isolates found in china share high sequence identity ([98%) and have more than 97% sequence identity with tylcvil[ il:reo] ( ...	2009	19590945
in vitro propagation of plant virus using different forms of plant tissue culture and modes of culture operation.	plant virus accumulation was investigated in vitro using three different forms of plant tissue culture. suspended cells, hairy roots and shooty teratomas of nicotiana benthamiana were infected with tobacco mosaic virus (tmv) using the same initial virus:biomass ratio. viral infection did not affect tissue growth or morphology in any of the three culture systems. average maximum virus concentrations in hairy roots and shooty teratomas were similar and about an order of magnitude higher than in su ...	2009	19616595
expression dynamics and ultrastructural localization of epitope-tagged abutilon mosaic virus nuclear shuttle and movement proteins in nicotiana benthamiana cells.	the geminivirus abutilon mosaic virus (abmv) encodes two proteins which are essential for viral spread within plants. the nuclear shuttle protein (nsp) transfers viral dna between the nucleus and cytoplasm, whereas the movement protein (mp) facilitates transport between cells through plasmodesmata and long-distance via phloem. an inducible overexpression system for epitope-tagged nsp and mp in plants yielded unprecedented amounts of both proteins. western blots revealed extensive posttranslation ...	2009	19628237
tomato bushy stunt virus recombination guided by introduced microrna target sequences.	previously we described tomato bushy stunt virus (tbsv) vectors, which retained their capsid protein gene and were engineered with magnesium chelatase (chlh) and phytoene desaturase (pds) gene sequences from nicotiana benthamiana. upon plant infection, these vectors eventually lost the inserted sequences, presumably as a result of recombination. here, we modified the same vectors to also contain the plant mir171 or mir159 target sequences immediately 3' of the silencing inserts. we inoculated n. ...	2009	19640975
nbhb1, nicotiana benthamiana homeobox 1, is a jasmonic acid-dependent positive regulator of pathogen-induced plant cell death.	induction of cell death is an important component of plant defense against pathogens. there have been many reports on the role of phytohormones in pathogen-induced cell death, but jasmonic acid (ja) has not been implicated as a regulator of the response. here, we report the function of nbhb1, nicotiana benthamiana homeobox1, in pathogen-induced cell death in connection with ja signaling. involvement of nbhb1 in cell death was analysed by gain- and loss-of-function studies using agrobacterium-med ...	2009	19645736
regulation of defense gene expression by arabidopsis srfr1.	reduced growth and viability is a common phenotype of plants with constitutively activated pathogen defenses. one branch of the plant innate immunity system, effector-triggered immunity, is especially potent and requires tight control to enable normal plant development. while some facets of this control that directly regulate resistance protein abundance or activity have been documented, general control of effector-triggered signaling sensitivity is poorly understood. we recently identified supp ...	2009	19649196
turnip mosaic virus rna replication complex vesicles are mobile, align with microfilaments, and are each derived from a single viral genome.	nicotiana benthamiana plants were agroinoculated with an infectious cdna clone of turnip mosaic virus (tumv) that was engineered to express a fluorescent protein (green fluorescent protein [gfp] or mcherry) fused to the viral 6k2 protein known to induce vesicle formation. cytoplasmic fluorescent discrete protein structures were observed in infected cells, corresponding to the vesicles containing the viral rna replication complex. the vesicles were motile and aligned with microfilaments. intracel ...	2009	19656892
molecular characterisation and infectivity of a "legumovirus" (genus begomovirus: family geminiviridae) infecting the leguminous weed rhynchosia minima in pakistan.	the legume yellow mosaic viruses (lymvs) that cause extensive losses to grain legumes across southern asia are an evolutionarily unusual group of begomoviruses (genus begomovirus; family geminiviridae) with bipartite genomes. all previously identified lymvs were isolated from leguminous crop species. here we have identified a virus related to the lymvs in a common weed, the legume rhynchosia minima originating from pakistan. analysis of the sequence of the virus shows it to be a typical bipartit ...	2009	19664665
characterization of the cassava geminivirus transcription activation protein putative nuclear localization signal.	the geminivirus transcription activation protein (trap) localizes to the nucleus and contains a putative nuclear localization signal (nls) ((28)prrrr(32)) on the n-terminus. the role of individual residues of this putative nls on nuclear localization and symptom induction was investigated using trap of east african cassava mosaic cameroon virus (eacmcv). subcellular localization was conducted using the green fluorescent protein (gfp). results showed that the proline residue at position 28 (pro-2 ...	2009	19665038
proteolysis of a negative regulator of innate immunity is dependent on resistance genes in tomato and nicotiana benthamiana and induced by multiple bacterial effectors.	rpm1-interacting protein 4 (rin4), a negative regulator of the basal defense response in plants, is targeted by multiple bacterial virulence effectors. we show that rin4 degradation is induced by the effector avrpto from pseudomonas syringae and that this degradation in solanaceous plants is dependent on the resistance protein, pto, a protein kinase, and prf, a nucleotide binding site-leucine-rich repeat protein. our data demonstrate overlap between two of the best-characterized pathways for rec ...	2009	19671880
protein mislocalization in plant cells using a gfp-binding chromobody.	a key challenge in cell biology is to directly link protein localization to function. the green fluorescent protein (gfp)-binding protein, gbp, is a 13-kda soluble protein derived from a llama heavy chain antibody that binds with high affinity to gfp as well as to some gfp variants such as yellow fluorescent protein (yfp). a gbp fusion to the red fluorescent protein (rfp), a molecule termed a chromobody, was previously used to trace in vivo the localization of various animal antigens. in this st ...	2009	19686537
characterization of a member of a new potyvirus species infecting arracacha in brazil.	an arracacha (arracacia xanthorrhiza) plant collected in brazil was found to be infected by a new virus. this viral isolate (named c17) systemically infected nicotiana benthamiana and apium graveolens. a polyclonal antibody was raised, and analysis of our arracacha germplasm collection showed a high infection rate of c17-like viruses (93% infection). sequencing of the ca. 1.7 kb 3'-terminal genomic region revealed a typical potyvirus genome organization. it shared less than 70% nucleotide identi ...	2009	19109690
functional characterization of a stilbene synthase gene using a transient expression system in planta.	the expression and functionality of a resveratrol synthase (rs) gene from peanut (arachis hypogaea) was studied using an agrobacterium tumefaciens-mediated transient expression system in nicotiana benthamiana leaves. functional analysis of rs was demonstrated by tracking its expression during 96 h. to measure the transcripts levels of rs transgene, real-time qrt-pcr was used and revealed that the highest level of transcripts was at 48 h post-transfection. western blot analyses showed that rs pro ...	2009	19116720
forca, a promoter element that responds to crosstalk between defense and light signaling.	recognition of pathogenic microorganisms triggers in plants comprehensive transcriptional reprogramming. in order to identify transcriptome-level control elements required for plant immune responses we are examining several sets of genes found by microarray experiments to be co-activated in arabidopsis thaliana (arabidopsis) seedlings infected with the oomycete hyaloperonospora parasitica. promoter motifs conserved in clusters of co-expressed genes may be involved in mediating coordinated gene a ...	2009	19128484
compromised virus-induced gene silencing in rdr6-deficient plants.	rna silencing in plants serves as a potent antiviral defense mechanism through the action of small interfering rnas (sirnas), which direct rna degradation. sirnas can be derived directly from the viral genome or via the action of host-encoded rna-dependent rna polymerases (rdrs). plant genomes encode multiple rdrs, and it has been demonstrated that plants defective for rdr6 hyperaccumulate several classes of virus. in this study, we compared the effectiveness of virus-induced gene silencing (vig ...	2009	19129420
allelic variants of the pseudomonas syringae type iii effector hopz1 are differentially recognized by plant resistance systems.	the bacterial plant pathogen pseudomonas syringae depends on the type iii secretion system and type iii-secreted effectors to cause disease in plants. hopz is a diverse family of type iii effectors widely distributed in p. syringae isolates. among the hopz homologs, hopz1 is ancient to p. syringae and has been shown to be under strong positive selection driven by plant resistance-imposed selective pressure. here, we characterized the virulence and avirulence functions of the three hopz1 alleles ...	2009	19132870
subcellular localization and expression of bamboo mosaic virus satellite rna-encoded protein.	the satellite rna of bamboo mosaic virus (satbamv) has a single open reading frame encoding a non-structural protein, p20, which facilitates long-distance movement of satbamv in bamv and satbamv co-infected plants. immunohistochemistry and immunoelectron microscopy revealed that the p20 protein accumulated in the cytoplasm and nuclei in co-infected cells. p20 and the helper virus coat protein (cp) were highly similar in their subcellular localization, except that aggregates of bamv virions were ...	2009	19141462
transient protein expression in three pisum sativum (green pea) varieties.	the expression of proteins in plants both transiently and via permanently transformed lines has been demonstrated by a number of groups. transient plant expression systems, due to high expression levels and speed of production, show greater promise for the manufacturing of biopharmaceuticals when compared to permanent transformants. expression vectors based on a tobacco mosaic virus (tmv) are the most commonly utilized and the primary plant used, nicotiana benthamiana, has demonstrated the abili ...	2009	19156736
grapevine fanleaf virus (gflv)-specific antibodies confer gflv and arabis mosaic virus (armv) resistance in nicotiana benthamiana.	grapevine fanleaf virus (gflv) is one of the most destructive pathogens of grapevine. in this study, we generated monoclonal antibodies binding specifically to the coat protein of gflv. antibody fl(3), which bound most strongly to gflv and showed cross-reactivity to arabis mosaic virus (armv), was used to construct the single-chain antibody fragment scfvgflvcp-55. to evaluate the potential of this single-chain variable fragment (scfv) to confer antibody-mediated virus resistance, transgenic nico ...	2009	19161351
chimeras between oilseed rape mosaic virus and tobacco mosaic virus highlight the relevant role of the tobamoviral rdrp as pathogenicity determinant in several hosts.	oilseed rape mosaic virus (ormv) is a tobamovirus taxonomically distinct from the type member of the genus, tobacco mosaic virus (tmv). both viruses display a specific host range, although they share certain hosts, such as arabidopsis thaliana, nicotiana benthamiana and n. tabacum, on which they induce different symptoms. using a gain-of-symptom approach, we generated chimeric viruses, starting from a tmv infectious clone, over which different regions of ormv were exchanged with their correspond ...	2009	19161353
tomato yellow leaf curl thailand virus-[y72] from yunnan is a monopartite begomovirus associated with dnabeta.	previous studies have shown that isolates of tomato yellow leaf curl thailand virus (tylcthv) originated from thailand are bipartite begomoviruses, while all the seven tylcthv isolates found in china are associated with dnabeta molecules. in this study, infectious clones of tylcthv isolate y72 (tylcthv-[y72]) and its dnabeta were constructed to verify the bipartite or monopartite nature of tylcthv. agroinoculation showed that tylcthv-[y72] alone was able to induce significant symptoms in nicotia ...	2009	19165588
efficient virus-induced gene silencing in plants using a modified geminivirus dna1 component.	virus-induced gene silencing (vigs) is currently recognized as a powerful reverse genetics tool for application in functional genomics. dna1, a satellite-like and single-stranded dna molecule associated with begomoviruses (family geminiviridae), has been shown to replicate autonomously but requires the helper virus for its dissemination. we developed a vigs vector based on the dna1 component of tobacco curly shoot virus (tbcsv), a monopartite begomovirus, by inserting a multiple cloning site bet ...	2009	19175519
rapid system for evaluating bioproduction capacity of complex pharmaceutical proteins in plants.	transgene product yield remains a key limitation in commercializing plant-derived pharmaceutical proteins. although significant progress has been made in understanding the roles of promoters, enhancers, integration sites, codon usage, cryptic rna sites, silencing, and product compartmentalization on product yield and quality, researchers still cannot reliably predict which proteins will be produced at high levels or what manipulations will guarantee enhanced productivity. we have optimized a sim ...	2009	19183893
expressing a whitefly groel protein in nicotiana benthamiana plants confers tolerance to tomato yellow leaf curl virus and cucumber mosaic virus, but not to grapevine virus a or tobacco mosaic virus.	transgenesis offers many ways to obtain virus-resistant plants. however, in most cases resistance is against a single virus or viral strain. we have taken a novel approach based on the ability of a whitefly endosymbiotic groel to bind viruses belonging to several genera, in vivo and in vitro. we have expressed the groel gene in nicotiana benthamiana plants, postulating that upon virus inoculation, groel will bind to virions, thereby interfering with pathogenesis. the transgenic plants were inocu ...	2009	19184338