| long-distance movement, virulence, and rna silencing suppression controlled by a single protein in hordei- and potyviruses: complementary functions between virus families. | rna silencing is a natural defense mechanism against genetic stress factors, including viruses. a mutant hordeivirus (barley stripe mosaic virus [bsmv]) lacking the gammab gene was confined to inoculated leaves in nicotiana benthamiana, but systemic infection was observed in transgenic n. benthamiana expressing the potyviral silencing suppressor protein hcpro, suggesting that the gammab protein may be a long-distance movement factor and have antisilencing activity. this was shown for gammab prot ... | 2002 | 12438624 |
| replication of potato spindle tuber viroid in cultured cells of tobacco and nicotiana benthamiana: the role of specific nucleotides in determining replication levels for host adaptation. | we have developed an electroporation protocol to inoculate cultured cells of tobacco and nicotiana benthamiana with in vitro transcripts of potato spindle tuber viroid (pstvd) to characterize viroid structural features that determine replication efficiency at the cellular level. both (+)- and (-)-strands of pstvd were detected by northern blots as early as 6 h postinoculation (h.p.i.). accumulation of the (+)-circular pstvd increased very rapidly starting at 24 h.p.i. and continued beyond 6 days ... | 2002 | 12441088 |
| virus-induced silencing of ftsh gene in nicotiana benthmiana causes a striking bleached leaf phenotype. | a recombinant potato virus x (pvx) vector, ptxs.ftsh, harboring partial sequence of ftsh gene of nicotiana benthamiana was constructed to silence the expression of endogenous ftsh homologous gene in n. benthamiana. inoculation with in vitro runoff transcript of ptxs.ftsh to n. benthamiana plants allowed silencing of ftsh, causing striking bleaching of upper leaves reminiscent of var2 mutant phenotype of arabidopsis thaliana. ftsh-silenced plants exhibited no resistance against tobacco mosaic vir ... | 2002 | 12441644 |
| subcellular targeting domains of abutilon mosaic geminivirus movement protein bc1. | abutilon mosaic geminivirus (abmv) encodes two movement proteins, bv1 and bc1, which mediate the intra- and intercellular transport of viral dna in plants cooperatively. it has been shown previously that singly expressed bc1, fused to green fluorescent protein (gfp), accumulates preferentially either at the cell periphery or around the nucleus in separate plant cells. to define the bc1 domains responsible for understanding the subcellular sorting, deletion mutants were fused to gfp and expressed ... | 2002 | 12491102 |
| negative-strand tospoviruses and tenuiviruses carry a gene for a suppressor of gene silencing at analogous genomic positions. | posttranscriptional silencing of a green fluorescent protein (gfp) transgene in nicotiana benthamiana plants was suppressed when these plants were infected with tomato spotted wilt virus (tswv), a plant-infecting member of the bunyaviridae: infection with tswv resulted in complete reactivation of gfp expression, similar to the case for potato virus y, but distinct from that for cucumber mosaic virus, two viruses known to carry genes encoding silencing suppressor proteins. agrobacterium-based lea ... | 2003 | 12502849 |
| the importance of alfalfa mosaic virus coat protein dimers in the initiation of replication. | deletion and substitution mutations affecting the oligomerization of alfalfa mosaic virus (amv) coat protein (cp) were studied in protoplasts to determine their effect on genome activation, an early step in amv replication. the cp mutants that formed dimers, cpdeltac9 and cpc-a(r)f, were highly active in initiating replication with 63-84% of wild-type (wt) cp activity. however, all mutants that did not form dimers, cpdeltac18, cpdeltac19, cpc-wfp, and cpc-w, were much less active with 19-33% of ... | 2003 | 12504539 |
| host-dependent recombination of a tomato bushy stunt virus coat protein mutant yields truncated capsid subunits that form virus-like complexes which benefit systemic spread. | this study examined the contribution of the tomato bushy stunt virus (tbsv) coat protein (cp) and its corresponding rna to systemic infection of plants. compared to results obtained with a mutant lacking the 5'-half of the cp gene, the presence of those cp-rna sequences in another mutant benefited tbsv infection on nicotiana benthamiana even though wild-type cp expression was eliminated by introduction of a small out-of-frame deletion. rt-pcr of viral rna associated with rapid infections establi ... | 2002 | 12504582 |
| generation and characterisation of functional recombinant antibody fragments against rna replicase nib from plum pox virus. | a monoclonal antibody (mab 2a) able to react against the rna replicase nib from plum pox virus (ppv) was obtained and used for generating a specific scfv fragment. the vh and vl coding sequences were cloned and expressed as a fusion scfv protein to alkaline phosphatase. this fusion protein was able to recognise viral nib in both western and tissue-print elisa blots. the affinity and specificity of scfv2a for nib was similar to that of the parental mab and the region yleafy from ppv-nib was ident ... | 2003 | 12535657 |
| molecular analysis of the cucumber leaf spot virus genome. | full-length clones of the genome of the aureusvirus, cucumber leaf spot virus (clsv), have been constructed and infectious t7 polymerase derived synthetic transcripts have been produced. mutational analysis of the genome indicates a role for p84 in viral rna replication, the cp in systemic movement, p27 in viral cell-to-cell movement and p17 in symptom induction. a clsv mutant lacking orfs for the cp, p27 and p17 (clsv yx) was capable of replication and systemic movement in transgenic nicotiana ... | 2003 | 12573495 |
| dynamics of the vigs-mediated chimeric silencing of the nicotiana benthamiana chlh gene and of the tobacco mosaic virus vector. | the chlh gene, encoding for the h subunit of the magnesium chelatase enzyme, was silenced in nicotiana bentahamiana plants by virus-induced gene silencing (vigs), using tobacco mosaic virus (tmv) expression vector. strong silencing of the chlh target gene was initiated only in the apical tissues, in which the endogenous transcription level of the target gene and the level of tmv vector rna were both very high. the virus vector was also targeted by vigs, and its suppression was correlated with th ... | 2003 | 12575743 |
| agrosuppression: a bioassay for the hypersensitive response suited to high-throughput screening. | we describe a novel method, agrosuppression, that addresses the need for an assay of the hypersensitive response (hr) in intact plants that is rapid and adapted to high-throughput functional screening of plant and pathogen genes. the agrosuppression assay is based on inoculation of intact plants with a mixture of agrobacterium tumefaciens strains carrying (i) a binary plasmid with one or more candidate hr-inducing genes and (ii) a tumor-inducing (oncogenic) t-dna. in the absence of hr induction, ... | 2003 | 12580277 |
| a naturally occurring recombinant dna-a of a typical bipartite begomovirus does not require the cognate dna-b to infect nicotiana benthamiana systemically. | species of the genus begomovirus (family geminiviridae) found in the western hemisphere typically have a bipartite genome that consists of two 2.6 kb dna genomic components, dna-a and dna-b. we have identified and cloned genomic components of a new tomato-infecting begomovirus from brazil, for which the name tomato crinkle leaf yellows virus (tcrlyv) is proposed, and a dna-a variant of tomato chlorotic mottle virus (tocmv-[mg-bt1]). sequence analysis revealed that tcrlyv was most closely related ... | 2003 | 12604824 |
| use of green fluorescent protein to quantify the growth of colletotrichum during infection of tobacco. | to develop a quantitative assay of fungal growth inside plant tissues, strains of colletotrichum destructivum and colletotrichum orbiculare were transformed with a modified green fluorescent protein (gfp) gene fused with a glyceraldehyde-3-phosphate dehydrogenase promoter from aspergillus nidulans. transformants expressed gfp in culture and had the same growth rate and general appearance as the wild type. gfp was observed in all fungal structures during infection of leaves of nicotiana benthamia ... | 2003 | 12609730 |
| nicotiana benthamiana gp91phox homologs nbrboha and nbrbohb participate in h2o2 accumulation and resistance to phytophthora infestans. | active oxygen species (aos) are responsible for triggering defense responses in plants. respiratory burst oxidase homologs (rboh genes) have been implicated in aos generation. we have isolated two rboh cdnas, nbrboha and nbrbohb, from nicotiana benthamiana leaves. nbrboha was expressed constitutively at a low level and the transcripts were increased after mechanical stress of control leaf infiltration, whereas nbrbohb was induced specifically by the protein elicitor inf1 from the potato pathogen ... | 2003 | 12615943 |
| turnip crinkle virus coat protein mediates suppression of rna silencing in nicotiana benthamiana. | all of the protein products of turnip crinkle virus (tcv; tombusviridae, carmovirus) were tested for their ability to suppress rna silencing of a reporter gene after transient expression in agrobacterium-infiltrated nicotiana benthamiana leaves. only the capsid protein, p38, showed suppression activity, although this was not obvious when p38 was expressed as part of a tcv infection of the same tissues. when p38 was expressed from a pvx vector, symptoms with enhanced severity that correlated with ... | 2003 | 12620795 |
| immunodetection and fluorescent microscopy of transgenically expressed hordeivirus tgbp3 movement protein reveals its association with endoplasmic reticulum elements in close proximity to plasmodesmata. | the subcellular localization of the hydrophobic tgbp3 protein of poa semilatent virus (pslv, genus hordeivirus) was studied in transgenic plants using fluorescent microscopy to detect green fluorescent protein (gfp)-tagged protein and immunodetection with monoclonal antibodies (mabs) raised against the gfp-based fusion expressed in e. coli. in western blot analysis, mabs efficiently recognized the wild-type and gfp-fused pslv tgbp3 proteins expressed in transgenic nicotiana benthamiana, but fail ... | 2003 | 12655101 |
| potato mop-top virus: the coat protein-encoding rna and the gene for cysteine-rich protein are dispensable for systemic virus movement in nicotiana benthamiana. | full-length genomic cdna clones of the swedish isolate of potato mop-top virus (pmtv) were transcribed in vitro using t7 rna polymerase. the combination of rna 1, 2 and 3 synthesized in the presence of m(7)gpppg cap analogue was infectious when inoculated onto nicotiana benthamiana plants. also, the combination of rna 1 (encodes the viral replicase) with rna 3 [encodes the triple gene block proteins and a small cysteine-rich protein (crp)] was infectious and both rnas moved systemically in n. be ... | 2003 | 12655103 |
| molecular characterization of nbpaf encoding the alpha6 subunit of the 20s proteasome in nicotiana benthamiana. | the 26s proteasome involved in degradation of proteins covalently modified with polyubiquitin consists of the 20s proteasome and 19s regulatory complex. the nbpaf gene encoding the alpha6 subunit of the 20s proteasome was identified from nicotiana benthamiana. nbpaf exhibits high sequence homology with the corresponding genes from arabidopsis, human and yeast. the deduced amino acid sequence of nbpaf reveals that this protein contains the proteasome alpha-type subunits signature and nuclear loca ... | 2003 | 12661772 |
| c-terminal domain of a hevein-like protein from wasabia japonica has potent antimicrobial activity. | an antimicrobial protein, designated wjamp-1, was purified from leaves of wasabia japonica l. wjamp-1 showed antimicrobial activity against both fungi and bacteria. the deduced amino acid sequence of cdna of wjamp-1 showed 60% and 70% identity with a hevein from hevea brasiliansis and a hevein-like protein from arabidopsis thaliana, respectively. however, matured wjamp-1 lacked the hevein domain and may correspond to the c-terminal domain of hevein. southern blot analysis showed that one or two ... | 2003 | 12668776 |
| peptide-mediated broad-spectrum plant resistance to tospoviruses. | plant viruses have a significant impact on agronomic losses worldwide. a new strategy for engineering virus-resistant plants by transgenic expression of a dominant interfering peptide is presented here. this peptide of 29 aa strongly interacts with the nucleocapsid proteins (n) of different tospoviruses. transgenic nicotiana benthamiana lines expressing the peptide fused to a carrier protein were challenged with five different tospoviruses that have a nucleocapsid protein interacting with the pe ... | 2003 | 12682295 |
| different elongation pathways in the biosynthesis of acyl groups of trichome exudate sugar esters from various solanaceous plants. | two common pathways are known for elongation of aliphatic acids via acetate in biological organisms: the fatty acid synthase (fas) and the alpha-ketoacid elongation (alphakae) pathways. the alphakae route is utilized in many biosynthetic pathways, including the tricarboxylic acid cycle, leucine biosynthesis, and in formation of coenzyme b, glucosinolates, alpha-ketoadipate, sugar-ester acyl acids, short-chain alcohols of yeast and clostridium species, 2-amino-4-methylhex-4-enoic acid, and l-gamm ... | 2003 | 12687369 |
| in situ characterization of cymbidium ringspot tombusvirus infection-induced posttranscriptional gene silencing in nicotiana benthamiana. | in plants, posttranscriptional gene silencing (ptgs) is an ancient and effective defense mechanism against viral infection. a number of viruses encode proteins that suppress virus-activated ptgs. the p19 protein of tombusviruses is a potent ptgs suppressor which interferes with the onset of ptgs-generated systemic signaling and is not required for viral replication or for viral movement in nicotiana benthamiana. this unique feature of p19 suppressor allowed us to analyze the mechanism of ptgs-ba ... | 2003 | 12719602 |
| the potato virus x tgbp3 protein associates with the er network for virus cell-to-cell movement. | potato virus x (pvx) tgbp3 is required for virus cell-to-cell movement. cell-to-cell movement of tgbp3 was studied using biolistic bombardment of plasmids expressing gfp:tgbp3. tgbp3 moves between cells in nicotiana benthamiana, but requires tgbp1 to move in n. tabacum leaves. in tobacco leaves gfp:tgbp3 accumulated in a pattern resembling the endoplasmic reticulum (er). to determine if the er network is important for gfp:tgbp3 and for pvx cell-to-cell movement, a single mutation inhibiting memb ... | 2003 | 12726734 |
| p58(ipk), a plant ortholog of double-stranded rna-dependent protein kinase pkr inhibitor, functions in viral pathogenesis. | p58(ipk) is a cellular inhibitor of the mammalian double-stranded rna-activated protein kinase (pkr). here we provide evidence for the existence of its homolog in plants and its role in viral infection at the organism level. viral infection of p58(ipk)-silenced nicotiana benthamiana and arabidopsis knockouts leads to host death. this host cell death is associated with phosphorylation of the alpha subunit of eukaryotic translation initiation factor (eif-2alpha). loss of p58(ipk) leads to reduced ... | 2003 | 12737801 |
| use of spring beauty latent virus to identify compatible interactions between bromovirus components required for virus infection. | spring beauty latent virus (sblv) is a member of the genus bromovirus, and is closely related to brome mosaic virus (bmv) and cowpea chlorotic mottle virus (ccmv). compatible interactions between viral components are required for successful infection of plants by bmv and ccmv. to further our understanding of interactions between bromovirus components, we used sblv to produce reassortants among the three bromoviruses. we found that sblv rna 2 functioned with heterologous bromovirus rna 1 in infec ... | 2003 | 12771403 |
| plant-based heterologous expression of mal d 2, a thaumatin-like protein and allergen of apple (malus domestica), and its characterization as an antifungal protein. | mal d 2 is a thaumatin-like protein and important allergen of apple fruits that is associated with ige-mediated symptoms in apple allergic individuals. we obtained a full-length cdna clone of mal d 2 from rna isolated from ripe apple (malus domestica cv. golden delicious). the cdna's open reading frame encodes a protein of 246 amino acid residues including a signal peptide of 24 residues and two putative glycosylation sites. the deduced amino acid sequence of the mature mal d 2 protein results i ... | 2003 | 12787673 |
| transient expression of arabidopsis thaliana ascorbate peroxidase 3 in nicotiana benthamiana plants infected with recombinant potato virus x. | we have explored the transient over-expression of arabidopsis thaliana ascorbate peroxidase 3 (apx3) in nicotiana benthamiana using a viral vector based on the potato virus x (pvx). plants infected with a pvx:apx3 hybrid had a similar progression of viral particles compared to control plants infected with a pvx:gfp hybrid, indicating that infection was not affected by the over-expression of heterologous apx3. our results also showed that in pvx:apx3-infected plants, the hybrid virus directed a h ... | 2003 | 12789421 |
| virus-induced silencing of sterol biosynthetic genes: identification of a nicotiana tabacum l. obtusifoliol-14alpha-demethylase (cyp51) by genetic manipulation of the sterol biosynthetic pathway in nicotiana benthamiana l. | obtusifoliol-14alpha-demethylase (cyp51) is implicated in plant sterol biosynthesis. an arabidopsis expressed sequence tag encoding a cyp51 was used as a probe to isolate nicotiana tabacum l. cdnas. two types of cdna clones were identified. nt cyp51-1 and nt cyp51-2 shared 97% identity together and around 75% with other plant cyp51s. the function of the encoded enzyme has been demonstrated in planta by manipulating the sterol biosynthetic pathway at the gene level. the endogenous cyp51 of nicoti ... | 2003 | 12810855 |
| a novel co-delivery system consisting of a tomato bushy stunt virus and a defective interfering rna for studying gene silencing. | virus induced gene silencing (vigs) and suppression are rna-specific defense and counter-defense circuits in plant-virus interactions. these phenomena have been investigated extensively with an agrobacterium-mediated transient expression system. in this study, a virus-based transient expression system was developed to study these phenomena. a tomato bushy stunt virus (tbsv) viral vector with an inactivated p19 suppressor gene, referred to as phst2-14, was chosen to express the p1 of tobacco etch ... | 2003 | 12821195 |
| expression of self-complementary hairpin rna under the control of the rolc promoter confers systemic disease resistance to plum pox virus without preventing local infection. | homology-dependent selective degradation of rna, or post-transcriptional gene silencing (ptgs), is involved in several biological phenomena, including adaptative defense mechanisms against plant viruses. small interfering rnas mediate the selective degradation of target rna by guiding a multicomponent rnase. expression of self-complementary hairpin rnas within two complementary regions separated by an intron elicits ptgs with high efficiency. plum pox virus (ppv) is the etiological agent of shar ... | 2003 | 12823862 |
| effect of temperature on plum pox virus infection. | one of the key factors of progress of an epidemic is the duration of virus availability for a vector in plants, which could be influenced by temperature. using five epidemiologically different isolates of plum pox virus (ppv) we studied the effect of temperature on the virus infectivity, intensity of disease symptoms and virus accumulation in nicotiana benthamiana plants as determined by a double-antibody sandwich-enzyme-linked immunosorbent assay (das-elisa). no differences in infectivity and i ... | 2003 | 12828345 |
| the pseudomonas syringae type iii-secreted protein hopptod2 possesses protein tyrosine phosphatase activity and suppresses programmed cell death in plants. | the bacterial plant pathogen pseudomonas syringae possesses a type iii protein secretion system that delivers many virulence proteins into plant cells. a subset of these proteins (called avr proteins) is recognized by the plant's innate immune system and triggers defences. one defence-associated response is the hypersensitive response (hr), a programmed cell death (pcd) of plant tissue. we have previously identified hopptod2 as a type iii secreted protein from p. s. pv. tomato dc3000. sequence a ... | 2003 | 12828636 |
| structural and mutational analyses of cis-acting sequences in the 5'-untranslated region of satellite rna of bamboo mosaic potexvirus. | the satellite rna of bamboo mosaic virus (satbamv) contains on open reading frame for a 20-kda protein that is flanked by a 5'-untranslated region (utr) of 159 nucleotides (nt) and a 3'-utr of 129 nt. a secondary structure was predicted for the 5'-utr of satbamv rna, which folds into a large stem-loop (lsl) and a small stem-loop. enzymatic probing confirmed the existence of lsl (nt 8-138) in the 5'-utr. the essential cis-acting sequences in the 5'-utr required for satbamv rna replication were de ... | 2003 | 12832220 |
| high-throughput viral expression of cdna-green fluorescent protein fusions reveals novel subcellular addresses and identifies unique proteins that interact with plasmodesmata. | a strategy was developed for the high-throughput localization of unknown expressed proteins in nicotiana benthamiana. libraries of random, partial cdnas fused to the 5' or 3' end of the gene for green fluorescent protein (gfp) were expressed in planta using a vector based on tobacco mosaic virus. viral populations were screened en masse on inoculated leaves using a confocal microscope fitted with water-dipping lenses. each viral infection site expressed a unique cdna-gfp fusion, allowing several ... | 2003 | 12837943 |
| virus-induced silencing of wipk and sipk genes reduces resistance to a bacterial pathogen, but has no effect on the inf1-induced hypersensitive response (hr) in nicotiana benthamiana. | activation of two mitogen-activated protein kinases (mapks), wound-induced protein kinase (wipk) and salicylic acid-induced protein kinase (sipk), is one of the earliest responses that occur in tobacco plants that have been wounded, treated with pathogen-derived elicitors or challenged with avirulent pathogens. we isolated cdnas for these mapks (nbwipkand nbsipk) from nicotiana benthamiana. the function of nbwipk and nbsipk in mediating the hypersensitive response (hr) triggered by infiltration ... | 2003 | 12838412 |
| the potato virus x tgbp2 protein association with the endoplasmic reticulum plays a role in but is not sufficient for viral cell-to-cell movement. | potato virus x (pvx) tgbp1, tgbp2, tgbp3, and coat protein are required for virus cell-to-cell movement. plasmids expressing gfp fused to tgbp2 were bombarded to leaf epidermal cells and gfp:tgbp2 moved cell to cell in nicotiana benthamiana leaves but not in nicotiana tabacum leaves. gfp:tgbp2 movement was observed in tgbp1-transgenic n. tabacum, indicating that tgbp2 requires tgbp1 to promote its movement in n. tabacum. in this study, gfp:tgbp2 was detected in a polygonal pattern that resembles ... | 2003 | 12890619 |
| two classes of subgenomic rna of grapevine virus a produced by internal controller elements. | grapevine virus a (gva), a species of the recently established genus vitivirus, consists of an approximately 7.3-kb single-stranded rna genome of positive polarity, organized into five open reading frames (orfs). the virus, which is closely associated with the grapevine rugose wood disease complex, has been poorly investigated genetically. we explored the production of viral rnas in a gva-infected nicotiana benthamiana herbaceous host and characterized one nested set of three 5'-terminal sgrnas ... | 2003 | 12919748 |
| identification of grapevines infected with divergent variants of grapevine virus a using variant-specific rt-pcr. | rt-pcrs, designed for the specific detection of molecular variants of grapevine virus a (gva), were applied to analysis of the virus from various grapevines and isolates recovered from these grapevines in nicotiana benthamiana. results of sscp, cloning and sequencing revealed that the combination of these rt-pcr techniques permits reliable and rapid identification of grapevines mixed-infected with divergent variants of gva. the results suggest that such grapevines are very common among gva-infec ... | 2003 | 12951225 |
| individualized human scfv vaccines produced in plants: humoral anti-idiotype responses in vaccinated mice confirm relevance to the tumor ig. | we have developed a method for rapidly producing in plants the idiotype regions of the tumor-specific ig as single-chain fv (scfv) proteins for use in the treatment of non-hodgkin's lymphoma. variable region gene sequences were generated from either a tumor hybridoma or human tumor biopsy cells, and idiotype domains were joined by a novel linker and cloned into a modified tobacco mosaic virus (tmv) vector designed to secrete the scfv protein in infected nicotiana benthamiana plants. thirty-eight ... | 2003 | 12957399 |
| fluorescent labelling reveals spatial separation of potyvirus populations in mixed infected nicotiana benthamiana plants. | the distribution of potyviruses in mixed infected nicotiana benthamiana plants was investigated by using green and red fluorescent proteins (gfp, dsred). full-length cdna clones of plum pox virus (ppv-nat-agfps; ppv-nat-red), tobacco vein mottling virus (tvmv-gfp; tvmv-red) and clover yellow vein virus (clyvv-gfp) expressing fluorescent proteins, referred to here as labelled viruses, were used to characterize the distribution of different potyviral populations (e.g. tvmv-gfp/ppv-nat-red), as wel ... | 2003 | 13679622 |
| suppressor activity of potyviral and cucumoviral infections in potyvirus-induced transgene silencing. | the process known as 'recovery' by which virus-infected plants become resistant to the infection is an interesting phenomenon where both rna silencing and virus resistance fully converge. in a previous study, we showed that transgenic nicotiana benthamiana nibv3 plants, transformed with a mutated nib coding sequence from plum pox virus (ppv), showed a delayed, very specific, resistance phenotype, which was induced by the initial infection. this recovery was the consequence of the activation of a ... | 2003 | 13679623 |
| virus-induced gene silencing. | in the postgenomic era, large-scale functional genomic approaches are necessary for converting sequence information into functional information. a para-genetic approach, called virus-induced gene silencing (vigs), offers a rapid means of gaining insight into gene function in plants. vigs system could be used to suppress endogenous gene expression by infecting plants with a recombinant virus vector (vigs vector) carrying host-derived sequence. here, we describe the use of tobacco rattle virus (tr ... | 2003 | 14501071 |
| bovine herpes virus gd protein produced in plants using a recombinant tobacco mosaic virus (tmv) vector possesses authentic antigenicity. | a tobacco mosaic virus (tmv)-based vector was utilized for expression of a cytosolic form of the bovine herpesvirus type 1 (bhv-1) protein glycoprotein d (gdc). nicotiana benthamiana plants were harvested 7 days after inoculation with rna transcripts derived from the tmv-gdc recombinant virus. recombinant gdc protein of expected electrophoretic mobility accumulated in inoculated leaves to a concentration of about 20 micrograms/g of fresh leaf tissue. oil-based vaccines were formulated with crude ... | 2003 | 14505899 |
| molecular chaperone hsp90 associates with resistance protein n and its signaling proteins sgt1 and rar1 to modulate an innate immune response in plants. | sgt1 and rar1 are important signaling components of resistance (r) gene-mediated plant innate immune responses. here we report that sgt1 and rar1 associate with the molecular chaperone hsp90. in addition, we show that hsp90 associates with the resistance protein n that confers resistance to tobacco mosaic virus. this suggests that hsp90-sgt1-rar1 and r proteins might exist in one complex. suppression of hsp90 in nicotiana benthamiana plants shows that it plays an important role in plant growth a ... | 2004 | 14583611 |
| cucumovirus- and bromovirus-encoded movement functions potentiate cell-to-cell movement of tobamo- and potexviruses. | cucumber mosaic virus (cmv, a cucumovirus) and brome mosaic virus (bmv, a bromovirus) require the coat protein (cp) in addition to the 3a movement protein (mp) for cell-to-cell movement, while cowpea chlorotic mottle virus (ccmv, a bromovirus) does not. using bombardment-mediated transcomplementation assays, we investigated whether the movement functions encoded by these viruses potentiate cell-to-cell movement of movement-defective tomato mosaic virus (tomv, a tobamovirus) and potato virus x (p ... | 2003 | 14592759 |
| high throughput virus-induced gene silencing implicates heat shock protein 90 in plant disease resistance. | virus-induced gene silencing was used to assess the function of random nicotiana benthamiana cdnas in disease resistance. out of 4992 cdnas tested from a normalized library, there were 79 that suppressed a hypersensitive response (hr) associated with pto-mediated resistance against pseudomonas syringae. however, only six of these clones blocked the pto-mediated suppression of p.syringae growth. the three clones giving the strongest loss of pto resistance had inserts corresponding to hsp90 and al ... | 2003 | 14592968 |
| synthesis of l-ascorbic acid in the phloem. | although plants are the main source of vitamin c in the human diet, we still have a limited understanding of how plants synthesise l-ascorbic acid (asa) and what regulates its concentration in different plant tissues. in particular, the enormous variability in the vitamin c content of storage organs from different plants remains unexplained. possible sources of asa in plant storage organs include in situ synthesis and long-distance transport of asa synthesised in other tissues via the phloem. in ... | 2003 | 14633288 |
| novel system for the simultaneous analysis of geminivirus dna replication and plant interactions in nicotiana benthamiana. | the origin of replication of african cassava mosaic virus (acmv) and a gene expression vector based on potato virus x were exploited to devise an in planta system for functional analysis of the geminivirus replication-associated protein (rep) in transgenic nicotiana benthamiana line pori-2. this line contains an integrated copy of a tandem repeat of the acmv origin of replication flanking nonviral sequences that can be mobilized and replicated by rep as an episomal replicon. a rep-gfp fusion pro ... | 2003 | 14645587 |
| plant sterol biosynthesis: identification of two distinct families of sterol 4alpha-methyl oxidases. | in plants, the conversion of cycloartenol into functional phytosterols requires the removal of the two methyl groups at c-4 by an enzymic complex including a sterol 4alpha-methyl oxidase (smo). we report the cloning of candidate genes for smos in arabidopsis thaliana, belonging to two distinct families termed smo1 and smo2 and containing three and two isoforms respectively. smo1 and smo2 shared low sequence identity with each other and were orthologous to the erg25 gene from saccharomyces cerevi ... | 2004 | 14653780 |
| the tomato resistance protein bs4 is a predicted non-nuclear tir-nb-lrr protein that mediates defense responses to severely truncated derivatives of avrbs4 and overexpressed avrbs3. | the lycopersicon esculentum bs4 resistance (r) gene specifies recognition of xanthomonas campestris pv. vesicatoria (xcv) strains that express the cognate avrbs4 avirulence protein. bs4 was isolated by positional cloning and is predicted to encode a nucleotide-binding leucine-rich repeat (nb-lrr) protein that is homologous to tobacco n and potato y-1 resistance proteins. xcv infection tests demonstrate that bs4 confers perception of avrbs4 but not the 97% identical avrbs3 protein. however, when ... | 2004 | 14675431 |
| gene expression analysis of plant host-pathogen interactions by supersage. | the type iii restriction endonuclease ecop15i was used in isolating fragments of 26 bp from defined positions of cdnas. we call this substantially improved variant to the conventional serial analysis of gene expression (sage) procedure "supersage." by applying supersage to magnaporthe grisea (blast)-infected rice leaves, gene expression profiles of both the rice host and blast fungus were simultaneously monitored by making use of the fully sequenced genomes of both organisms, revealing that the ... | 2003 | 14676315 |
| pseudomonas syringae type iii secretion system targeting signals and novel effectors studied with a cya translocation reporter. | pseudomonas syringae pv. tomato strain dc3000 is a pathogen of tomato and arabidopsis: the hrp-hrc-encoded type iii secretion system (ttss), which injects bacterial effector proteins (primarily called hop or avr proteins) into plant cells, is required for pathogenicity. in addition to being regulated by the hrpl alternative sigma factor, most avr or hop genes encode proteins with n termini that have several characteristic features, including (i) a high percentage of ser residues, (ii) an aliphat ... | 2004 | 14702323 |
| arg-16 and arg-21 in the n-terminal region of the triple-gene-block protein 1 of bamboo mosaic virus are essential for virus movement. | the protein encoded by the first gene of the triple gene block (tgbp1) of potexviruses is required for movement of the viruses. it has been reported that single arg-->ala substitutions at position 11, 16 or 21 of tgbp1 of bamboo mosaic virus (bamv) eliminate its rna-binding activity, while substitutions at position 16 or 21 only affect its ntpase activity (liou et al., virology 277, 336-344, 2000). however, it remains unclear whether these arg-->ala substitutions also affect the movement of bamv ... | 2004 | 14718640 |
| proteomic analysis of the oxygen-evolving complex of photosystem ii under biotec stress: studies on nicotiana benthamiana infected with tobamoviruses. | we have previously shown that tobamovirus infection induces an inhibition of photosystem ii electron transport, disturbing the oxygen-evolving complex (oec). in the infected plants, the oec polypeptide pattern was modified when compared to healthy plants, the levels of the psbp and psbq extrinsic proteins being lowered to different extents. in this work we have further investigated by two-dimensional polyacrylamide gel electrophoresis (2-de) the changes on the oec protein pattern of thylakoid me ... | 2004 | 14760711 |
| plant virus expression systems for transient production of recombinant allergens in nicotiana benthamiana. | in recent years, several studies have demonstrated the use of autonomously replicating plant viruses as vehicles to express a variety of therapeutic molecules of pharmaceutical interest. plant virus vectors for expression of heterologous proteins in plants represent an attractive biotechnological tool to complement the conventional production of recombinant proteins in bacterial, fungal, or mammalian cells. virus vectors are advantageous when high levels of gene expression are desired within a s ... | 2004 | 14962756 |
| a cysteine-rich plant protein potentiates potyvirus movement through an interaction with the virus genome-linked protein vpg. | we have identified a cellular factor that interacts with the virus genome-linked proteins (vpgs) of a diverse range of potyviruses. the factor, called potyvirus vpg-interacting protein (pvip), is a plant-specific protein with homologues in all the species examined, i.e., pea, arabidopsis thaliana, and nicotiana benthamiana. the sequence of pvip does not identify a specific function, although the existence of a "phd finger" domain may implicate the protein in transcriptional control through chrom ... | 2004 | 14963126 |
| host-specific generation and maintenance of tomato bushy stunt virus defective interfering rnas. | the accumulation of tomato bushy stunt virus (tbsv) defective interfering rnas (dis) has been observed in several species of plants, but the involvement of host-specific processes and the functional role of dis are still poorly understood. in this study, the accumulation of dis was compared after several passages of tbsv through nicotiana benthamiana and pepper (capsicum annuum). as anticipated, passages of wild-type tbsv through n. benthamiana resulted in the accumulation of significant levels ... | 2004 | 14964533 |
| short deletions in nuclear targeting sequences of african cassava mosaic virus coat protein prevent geminivirus twinned particle formation. | coat proteins (cps) of geminiviruses are multifunctional proteins. using transient expression experiments, we have recently identified putative sequence motifs of african cassava mosaic virus (acmv) cp involved in nuclear import (nls) and export (nes) (virology 286 (2001) 373). here, we report on the effect of corresponding deletion mutants in the context of infecting viruses. since nls and nes may overlap with dna binding and multimerisation domains, we have investigated their effect on viral i ... | 2004 | 14972538 |
| interaction between a geminivirus replication protein and the plant sumoylation system. | geminiviruses are small dna viruses that replicate in nuclei of infected plant cells after accumulation of host replication machinery. tomato golden mosaic virus (tgmv) and tomato yellow leaf curl sardinia virus (tylcsv) encode a protein, repac1 (or rep), that is essential for viral replication. rep/repac1 is an oligomeric protein that binds to double-stranded dna, catalyzes cleavage and ligation of single-stranded dna, and is sufficient for host induction. it also interacts with several host pr ... | 2004 | 14990696 |
| cell-to-cell, but not long-distance, spread of rna silencing that is induced in individual epidermal cells. | a turnip crinkle virus (tcv)-based system was devised to discriminate cell-to-cell and systemic long-distance spread of rna silencing in plants. modified tcv-gfpdeltacp, constructed by replacing the coat protein (cp) gene with the green fluorescent protein (gfp) gene, replicated in single epidermal cells but failed to move from cell to cell in nicotiana benthamiana. mechanical inoculation of tcv-gfpdeltacp induced effective rna silencing in single epidermal cells which spread from cell to cell t ... | 2004 | 14990735 |
| in vitro recombinants of two nearly identical potyviral isolates express novel virulence and symptom phenotypes in plants. | six novel chimeric viruses were constructed by sequentially exchanging segments of the viral genomes between the infectious cdna clone (ppva-b11) of potato virus a (isolate pva-b11) and pufl, an almost identical infectious cdna of pva (isolate u) made in this study. the infectious in vitro transcripts of pufl and ppva-b11 caused similar severe mosaic and leaf malformation phenotypes in systemically infected leaves of nicotiana benthamiana. in contrast, one chimera induced a unique phenotype of y ... | 2004 | 14993660 |
| satellite panicum mosaic virus capsid protein elicits symptoms on a nonhost plant and interferes with a suppressor of virus-induced gene silencing. | the capsid protein (cp) of satellite panicum mosaic virus (spmv) has been implicated as a pathogenicity factor, inducing severe chlorosis on millet plants co-infected with spmv and its helper virus, panicum mosaic virus (pmv). in this study, we tested the effects of spmv cp on nicotiana benthamiana, a plant that does not support pmv+spmv infections. spmv cp expressed from a potato virus x (pvx) gene vector elicited necrotic lesions on n. benthamiana. pathogenicity factors often have the addition ... | 2004 | 15000393 |
| red clover necrotic mosaic virus replication proteins accumulate at the endoplasmic reticulum. | red clover necrotic mosaic virus (rcnmv) encodes n-terminally overlapping proteins of 27 and 88 kda (p27 and p88) known to be required for replication. green fluorescent protein (gfp) fusions were used to visualize the location of p27 and p88 within nicotiana benthamiana cells. gfp:p27 fusions localized to the endoplasmic reticulum (er), co-localized with er-targeted yellow fluorescent protein and caused membrane restructuring and proliferation. cellular fractionation of virus-inoculated n. bent ... | 2004 | 15016550 |
| virus survival of rna silencing without deploying protein-mediated suppression in nicotiana benthamiana. | rna silencing represents an evolutionarily conserved defence mechanism that plays a key antiviral role in protecting plants and animals against virus infection. to counterattack, plant, animal and fungal viruses produce proteins capable of suppressing rna silencing. here, we report an unprecedented phenomenon that potato virus x, a single-stranded positive rna virus, is able to survive rna silencing without deploying protein-mediated anti-silencing by revealing an unexpected symptom re-emergence ... | 2004 | 15044003 |
| sida micrantha mosaic is associated with a complex infection of begomoviruses different from abutilon mosaic virus. | we report on the nucleotide sequences of geminiviruses of the genus bemogovirus infecting sida micrantha schr., a common weed in brazil. for decades, the mosaic frequently associated with sida plants was considered to be caused by a brazilian strain of abutilon mosaic virus (abmv). by infection studies and sequence comparisons, we demonstrate that it is associated with a complex of at least two begomoviruses as different from abmv as most south american geminiviruses. two molecules of dna a (a1, ... | 2004 | 15045569 |
| functional analysis of the final steps of the 1-deoxy-d-xylulose 5-phosphate (dxp) pathway to isoprenoids in plants using virus-induced gene silencing. | isoprenoid biosynthesis in plant plastids occurs via the 1-deoxy-d-xylulose 5-phosphate (dxp) pathway. we used tobacco rattle virus (trv) to posttranscriptionally silence the expression of the last two enzymes of this pathway, the ispg-encoded (e)-4-hydroxy-3-methylbut-2-enyl diphosphate synthase (hds) and the isph-encoded isopentenyl/dimethylallyl diphosphate synthase (idds), as well as isopentenyl/dimethylallyl diphosphate isomerase (idi), the enzyme that interconverts ipp and dmapp. trv-ispg ... | 2004 | 15064370 |
| a geminivirus ayvv-derived shuttle vector for tobacco by2 cells. | we have developed a plant- escherichia coli pasv shuttle vector from the essential elements of the ageratum yellow vein virus (ayvv). the geminivirus vector contains the ayvv genome with the coat-protein deletion, the e. coli vector backbone of puc19, a unique cloning site and gene expression cassettes for plant selection and reporter gene activity. the replication of pasv vectors was compared in nicotiana benthamiana and n. tabacum by2 cells, and the latter were found to be suitable for long-te ... | 2004 | 15069580 |
| salicylic acid is part of the mi-1-mediated defense response to root-knot nematode in tomato. | the mi-1 gene of tomato confers resistance against three species of root-knot nematode in tomato (lycopersicon esculentum). transformation of tomato carrying mi-1 with a construct expressing nahg, which encodes salicylate hydroxylase, a bacterial enzyme that degrades salicylic acid (sa) to catechol, results in partial loss of resistance to root-knot nematodes. exogenous sa was toxic to roots expressing nahg but not to control roots. this toxicity is most likely due to the production of catechol ... | 2004 | 15077667 |
| a natural variant of a host rna-dependent rna polymerase is associated with increased susceptibility to viruses by nicotiana benthamiana. | nicotiana benthamiana often displays more intense symptoms after infection by rna viruses than do other nicotiana species. here, we examined the role of rna-dependent rna polymerases (rdrps) in n. benthamiana antiviral defense. cdnas representing only two genes encoding rdrps were identified in n. benthamiana. one rdrp was similar in sequence to sde1/sgs2 required for maintenance of transgene silencing, whereas the second, named nbrdrp1m, was >90% identical in sequence to the salicylic acid (sa) ... | 2004 | 15079073 |
| potato virus x-induced gene silencing in leaves and tubers of potato. | virus induced gene silencing (vigs) is increasingly used to generate transient loss-of-function assays and has potential as a powerful reverse-genetics tool in functional genomic programs as a more rapid alternative to stable transformation. a previously described potato virus x (pvx) vigs vector has been shown to trigger silencing in the permissive host nicotiana benthamiana. this paper demonstrates that a pvx-based vigs vector is also effective in triggering a vigs response in both diploid and ... | 2004 | 15084725 |
| phloem specific expression driven by wheat dwarf geminivirus v-sense promoter in transgenic dicotyledonous species. | wheat dwarf geminivirus (wdv) is a single-stranded dna mastrevirus. the large intergenic region (lir) of wdv contains cis-acting elements essential for the replication of the genome as well as for the bidirectional transcription of virus genes. the lir was fused to the gus (uida) reporter gene and the wdv viral sense (v-sense) promoter activity derived from the stable integration of that promoter was analysed in transgenic dicot plants. various dicot species were tested, including nicotiana taba ... | 2004 | 15086824 |
| expression of the b subunit of the heat-labile enterotoxin of escherichia coli in tobacco mosaic virus-infected nicotiana benthamiana plants and its characterization as mucosal immunogen and adjuvant. | we have produced biologically active recombinant (r) ltb, the nontoxic b subunit of heat-labile toxin (lt) of escherichia coli in tobacco mosaic virus (tmv)-infected nicotiana benthamiana plants. we amplified the ltb encoding sequence with its leader and introduced a hexahistidyl tag and an endoplasmic reticulum retention signal. the resulting product was ligated into a tmv-based plant viral expression vector that was used for the generation of recombinant viral rna. eighty-nine percent of n. be ... | 2004 | 15099768 |
| rice dwarf phytoreovirus segment s6-encoded nonstructural protein has a cell-to-cell movement function. | rice dwarf virus (rdv) is a member of the genus phytoreovirus, which is composed of viruses with segmented double-stranded rna genomes. proteins that support the intercellular movement of these viruses in the host have not been identified. microprojectile bombardment was used to determine which open reading frames (orfs) support intercellular movement of a heterologous virus. a plasmid containing an infectious clone of potato virus x (pvx) defective in cell-to-cell movement and expressing either ... | 2004 | 15113917 |
| silencing of subfamily i of protein phosphatase 2a catalytic subunits results in activation of plant defense responses and localized cell death. | the central importance of protein phosphorylation in plant defense responses has been demonstrated by the isolation of several disease-resistance genes that encode protein kinases. in addition, there are many reports of changes in protein phosphorylation accompanying plant responses to pathogens. in contrast, little is known about the role of protein dephosphorylation in regulating plant defenses. we report that expression of the lepp2ac1 gene, which encodes a catalytic subunit of the heterotrim ... | 2004 | 15125764 |
| citrx thioredoxin interacts with the tomato cf-9 resistance protein and negatively regulates defence. | to identify proteins involved in tomato cf-9 resistance protein function, a yeast two-hybrid screen was undertaken using the cytoplasmic c-terminus of cf-9 as bait. a thioredoxin-homologous clone, interacting specifically with cf-9, was identified and called citrx (cf-9-interacting thioredoxin). virus-induced gene silencing (vigs) of citrx resulted in an accelerated cf-9/avr9-triggered hypersensitive response in both tomato and nicotiana benthamiana, accompanied by enhanced accumulation of react ... | 2004 | 15131698 |
| a modified viral satellite dna that suppresses gene expression in plants. | dnabeta is a type of single-stranded (ss) circular satellite dna found in association with monopartite-genome begomoviruses, such as tomato yellow leaf curl china virus isolate y10 (tylccnv-y10). y10 dnabeta is required for symptom expression in plants but depends on tylccnv-y10 genomic dna (dna-a) for replication and encapsidation. when we converted dnabeta into a gene-silencing vector (modified dnabeta (dnambeta)) by replacing its c1 open-reading frame (orf) with a multiple cloning site (mcs), ... | 2004 | 15144385 |
| molecular characterization of nbchmp1 encoding a homolog of human chmp1 in nicotiana benthamiana. | in humans, chmp1 encodes a protein of dual function that plays a role in both modification of chromatin structure and endosomal vesicle trafficking. recently, it was found that sal1, a chmp1 homolog in maize, is important for the development of the aleurone cell layers in maize endosperm. in this study, we investigated the structure and function of a nicotiana benthamiana chmp1 homolog designated nbchmp1. nbchmp1 encodes a small protein with a bipartite nuclear localization signal at its n-termi ... | 2004 | 15179039 |
| a method of high frequency virus-induced gene silencing in chili pepper (capsicum annuum l. cv. bukang). | using a tobacco rattle virus (trv)-based virus-induced gene silencing (vigs) system, expression of phytogene desaturase (pds) and ribulose-1,5-bisphosphate carboxylase small-subuit (rbcs) genes was suppressed in nicotiana benthamiana and pepper plants (capsicum annuum l. cv. bukang). the silenced phenotypes of pale yellow (rbcs), and photobleached leaves (pds), were invariably obvious 2 weeks after inoculation with the trv-based vector. in a parallel experiment, the same set of genes was silence ... | 2004 | 15179058 |
| the dna beta satellite component associated with ageratum yellow vein disease encodes an essential pathogenicity protein (betac1). | ageratum yellow vein disease (ayvd) is caused by the geminivirus ageratum yellow vein virus (ayvv) and an associated dna beta satellite. we have mapped a dna beta transcript to a highly conserved open reading frame (betac1 orf). the most abundant transcript 5'-terminus is located 8 bases upstream of the betac1 orf putative initiation codon while the transcript terminates at multiple sites downstream from the putative termination codon. disruption of betac1 protein expression by the introduction ... | 2004 | 15183051 |
| geminate structures of african cassava mosaic virus. | two types of geminate structures were purified from african cassava mosaic geminivirus (acmv)-infected nicotiana benthamiana plants and analyzed by electron cryomicroscopy and image reconstruction. after cesium sulfate density gradient centrifugation, they were separated into lighter top (t) and heavier bottom (b) components. t particles comigrated with host proteins, whereas b particles were concentrated in a cesium density typical for complete virions. both particles were composed of two incom ... | 2004 | 15194750 |
| single-chain antibodies against a plant viral rna-dependent rna polymerase confer virus resistance. | crop loss due to viral diseases is still a major problem for agriculture today. we present a strategy to achieve virus resistance based on the expression of single-chain fv fragments (scfvs) against a conserved domain in a plant viral rna-dependent rna polymerase (rdrp), a key enzyme in virus replication. the selected scfvs inhibited complementary rna synthesis of different plant virus rdrps in vitro and virus replication in planta. moreover, the scfvs also bound to the rdrp of the distantly rel ... | 2004 | 15195103 |
| molecular characterization of a melon necrotic spot virus strain that overcomes the resistance in melon and nonhost plants. | resistance of melon (cucumis melo l.) to melon necrotic spot virus (mnsv) is inherited as a single recessive gene, denoted nsv. no mnsv isolates described to date (e.g., mnsv-malpha5), except for the mnsv-264 strain described here, are able to overcome the resistance conferred by nsv. analysis of protoplasts of susceptible (nsv/-) and resistant (nsv/nsv) melon cultivars inoculated with mnsv-264 or mnsv-malpha5 indicated that the resistance trait conferred by this gene is expressed at the single- ... | 2004 | 15195949 |
| short interfering rna accumulation correlates with host recovery in dna virus-infected hosts, and gene silencing targets specific viral sequences. | viruses are both inducers and targets of posttranscriptional gene silencing (ptgs), a natural defense mechanism in plants. here we report molecular evidence of the ability of single-stranded dna (ssdna) viruses to induce ptgs in infected plants irrespective of the severity of or recovery from the symptoms. our results reveal that five distinct species of cassava-infecting geminiviruses were capable of triggering ptgs by producing two classes of virus-specific short interfering rnas (sirnas) of 2 ... | 2004 | 15220420 |
| virus-induced gene silencing in solanum species. | virus-induced gene silencing (vigs) has been used routinely in nicotiana benthamiana to assess functions of candidate genes and as a way to discover new genes required for diverse pathways, especially disease resistance signalling. vigs has recently been shown to work in arabidopsis thaliana and in tomato. here, we report that vigs using the tobacco rattle virus (trv) viral vector can be used in several solanum species, although the choice of vector and experimental conditions vary depending on ... | 2004 | 15225290 |
| mutation of phe50 to ser50 in the 126/183-kda proteins of odontoglossum ringspot virus abolishes virus replication but can be complemented and restored by exact reversion. | sequence comparison of a non-biologically active full-length cdna clone of odontoglossum ringspot virus (orsv) pot1 with a biologically active orsv cdna clone pot2 revealed a single nucleotide change of t-->c at position 211. this resulted in the change of phe50 in ot2 to ser50 in ot1. it was not the nucleotide but the amino acid change of phe50 that was responsible for the inability of ot1 to replicate. time-course experiments showed that no minus-strand rna synthesis was detected in mutants wi ... | 2004 | 15269387 |
| vdnep, an elicitor from verticillium dahliae, induces cotton plant wilting. | verticillium wilt is a vascular disease of cotton. the causal fungus, verticillium dahliae, secretes elicitors in culture. we have generated approximately 1,000 5'-terminal expressed sequence tags (ests) from a cultured mycelium of v. dahliae. a number of ests were found to encode proteins harboring putative signal peptides for secretion, and their cdnas were isolated. heterologous expression led to the identification of a protein with elicitor activities. this protein, named v. dahliae necrosis ... | 2004 | 15294839 |
| relocalization of nuclear aly proteins to the cytoplasm by the tomato bushy stunt virus p19 pathogenicity protein. | the p19 protein of tomato bushy stunt virus (tbsv) is a multifunctional pathogenicity determinant involved in suppression of posttranscriptional gene silencing, virus movement, and symptom induction. here, we report that p19 interacts with the conserved rna-binding domain of an as yet uncharacterized family of plant aly proteins that, in animals, are involved in export of rnas from the nucleus and transcriptional coactivation. we show that the four aly proteins encoded by the arabidopsis genome ... | 2004 | 15299117 |
| transient coexpression of individual genes encoded by the triple gene block of potato mop-top virus reveals requirements for tgbp1 trafficking. | tgbp1, tgbp2, and tgbp3, three plant virus movement proteins encoded by the "triple gene block" (tgb), may act in concert to facilitate cell-to-cell transport of viral rna genomes. transient expression of potato mop-top virus (genus pomovirus) movement proteins was used as a model to reconstruct interactions between tgb proteins. in bombarded epidermal cells of nicotiana benthamiana, green fluorescent protein (gfp)-tgbp1 was distributed uniformly. however, in the presence of tgbp2 and tgbp3, gfp ... | 2004 | 15305613 |
| preparation of polyclonal antibodies of rubisco large and small subunits and their application in the functional analysis of the genes. | spinach rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase) large (rbcl) and small (rbcs) subunits were separated by sds-page, and protein amount and purity were determined by bradford assay. polyclonal antibodies against rbcl and rbcs subunit were generated in female balb/c mice and had no cross-reaction with each other. a total of 81 microg antigens were used and 0.3 ml anti-sera with titer of 1:5000 were yielded. the antibodies were also applicable to study rbcl and rbcs in tobacco plan ... | 2004 | 15346203 |
| virus induced gene silencing of a deficiens ortholog in nicotiana benthamiana. | traditionally, developmental studies in plant biology have suffered from the lack of a convenient means to study gene function in non-model plant species. here we show that virus-induced gene silencing (vigs) is an effective new tool to study the function of orthologs of floral homeotic genes such as deficiens (def) in non-model systems. we used a tobacco rattle virus (trv)-based vigs approach to study the function of the nicotiana benthamiana def ortholog (nbdef). silencing of nbdef in n. benth ... | 2004 | 15356389 |
| tête à tête of tomato yellow leaf curl virus and tomato yellow leaf curl sardinia virus in single nuclei. | since 1997 two distinct geminivirus species, tomato yellow leaf curl sardinia virus (tylcsv) and tomato yellow leaf curl virus (tylcv), have caused a similar yellow leaf curl disease in tomato, coexisted in the fields of southern spain, and very frequently doubly infected single plants. tomatoes as well as experimental test plants (e.g., nicotiana benthamiana) showed enhanced symptoms upon mixed infections under greenhouse conditions. viral dna accumulated to a similar extent in singly and doubl ... | 2004 | 15367638 |
| dna gyrase is involved in chloroplast nucleoid partitioning. | dna gyrase, which catalyzes topological transformation of dna, plays an essential role in replication and transcription in prokaryotes. virus-induced gene silencing of nbgyra or nbgyrb, which putatively encode dna gyrase subunits a and b, respectively, resulted in leaf yellowing phenotypes in nicotiana benthamiana. nbgyra and nbgyrb complemented the gyra and gyrb temperature-sensitive mutations of escherichia coli, respectively, which indicates that the plant and bacterial subunits are functiona ... | 2004 | 15367714 |
| preserved antigenicity of hiv-1 p24 produced and purified in high yields from plants inoculated with a tobacco mosaic virus (tmv)-derived vector. | production of structural proteins from foot-and-mouth disease virus (fmdv) and bovine herpes virus (bhv-1) in nicotiana benthamiana through the use of a tobacco mosaic virus-based vector (tmv-30b) has been reported previously. the development of the tmv-30b-hisc vector, a new version that adds a c-terminal histidine (his) sequence to the foreign protein expressed is described. coding sequences from the fmdv vpl protein and the core protein, p24, from a clade c hiv-1 isolate from zambia were clon ... | 2004 | 15381357 |
| agrodrench: a novel and effective agroinoculation method for virus-induced gene silencing in roots and diverse solanaceous species. | summary virus-induced gene silencing (vigs) is an extremely powerful tool for plant functional genomics. we used tobacco rattle virus (trv)-derived vigs vectors expressed from binary vectors within agrobacterium to induce rna silencing in plants. leaf infiltration is the most common method of agroinoculation used for vigs but this method has limitations as it is laborious for large-scale screening and some plants are difficult to infiltrate. here we have developed a novel and simple method of ag ... | 2004 | 15447657 |
| expression of tombusvirus open reading frames 1 and 2 is sufficient for the replication of defective interfering, but not satellite, rna. | yeast cells co-expressing the replication proteins p36 and p95 of carnation italian ringspot virus (cirv) support the rna-dependent replication of several defective interfering (di) rnas derived from either the genome of cirv or the related cymbidium ringspot virus (cymrsv), but not the replication of a satellite rna (sat rna) originally associated with cymrsv. di, but not sat rna, was replicated in yeast cells co-expressing both di and sat rna. using transgenic nicotiana benthamiana plants cons ... | 2004 | 15448375 |
| orf6 of tobacco mosaic virus is a determinant of viral pathogenicity in nicotiana benthamiana. | tobacco mosaic virus (tmv) contains a sixth open reading frame (orf6) that potentially encodes a 4.8 kda protein. elimination of orf6 from tmv attenuated host responses in nicotiana benthamiana without alteration in virus accumulation. furthermore, heterologous expression of tmv orf6 from either potato virus x (pvx) or tobacco rattle virus (trv) vectors enhanced the virulence of both viruses in n. benthamiana, also without effects on their accumulation. by contrast, the presence or absence of tm ... | 2004 | 15448376 |
| potato virus x tgbp1 induces plasmodesmata gating and moves between cells in several host species whereas cp moves only in n. benthamiana leaves. | experiments were conducted to compare the plasmodesmal transport activities of potato virus x (pvx) tgbp1 and coat protein (cp) in several plant species. microinjection experiments indicated that tgbp1 gates plasmodesmata in nicotiana tabacum leaves. these results support previous microinjection studies indicating that tgbp1 gates plasmodesmata in nicotiana benthamiana and nicotiana clevelandii leaves. to study protein movement, plasmids expressing the green fluorescent protein (gfp) gene fused ... | 2004 | 15464839 |
| hoppton is a pseudomonas syringae hrp (type iii secretion system) cysteine protease effector that suppresses pathogen-induced necrosis associated with both compatible and incompatible plant interactions. | pseudomonas syringae pv. tomato dc3000 causes bacterial speck disease in tomato, and it elicits the hypersensitive response (hr) in non-host plants such as nicotiana tabacum and nicotiana benthamiana. the compatible and incompatible interactions of dc3000 with tomato and nicotiana spp., respectively, result in plant cell death, but the hr cell death occurs more rapidly and is associated with effective plant defense. both interactions require the hrp (hr and pathogenicity) type iii secretion syst ... | 2004 | 15469508 |
| unaltered complex n-glycan profiles in nicotiana benthamiana despite drastic reduction of beta1,2- n -acetylglucosaminyltransferase i activity. | udp-glcnac:alpha3-d-mannoside beta1,2- n -acetylglucosaminyltransferase i (gnti; ec 2.4.1.101) is a golgi-resident glycosyltransferase that is essential for the processing of oligomannose to hybrid and complex n-glycans in higher eukaryotes. the cdna of nicotiana tabacum gnti has been cloned and characterised previously. to assess the influence of gnti expression levels on the formation of complex n-glycans we used posttranscriptional gene silencing to knock down the expression of gnti in the to ... | 2004 | 15486460 |
| a conserved secondary structure in the hypervariable region at the 5' end of bamboo mosaic virus satellite rna is functionally interchangeable. | satellite rna (satrna) associated with bamboo mosaic virus (bamv) is dependent on bamv for replication and encapsidation. molecular analyses of total rna extracted from bamboo species collected worldwide revealed that 26 out of 61 bamv isolates harbored satbamv. among them, two phylogenetically distinguishable groups, a and b, with a genetic diversity of 6.9 +/- 0.7% were identified. greatest sequence diversity occurred in the 5' untranslated region (utr) that contained one hypervariable region ... | 2004 | 15527838 |