Publications

in vitro transcripts from cloned cdnas of the lettuce infectious yellows closterovirus bipartite genomic rnas are competent for replication in nicotiana benthamiana protoplasts.	full-length cloned cdnas of lettuce infectious yellows closterovirus (liyv) rnas 1 and 2 were constructed and fused to the bacteriophage t3 rna polymerase promoter. to assess rna replication, nicotiana benthamiana protoplasts were inoculated with liyv virion rnas and liyv cdna-derived in vitro transcripts. analysis of protoplasts inoculated with liyv virion rnas or capped (m7gpppg) in vitro transcripts from liyv rna 1 and 2 cdnas showed accumulation of liyv genomic and putative subgenomic rnas ( ...	1996	8806497
resistance to tomato yellow leaf curl geminivirus in nicotiana benthamiana plants transformed with a truncated viral c1 gene.	the c1 gene of tomato yellow leaf curl geminivirus (tylcv) encodes a multifunctional protein (rep) involved in replication. a truncated form of this gene, capable of expressing the n-terminal 210 amino acids (aa) of the rep protein, was cloned under the control of the camv 35s promoter and introduced into nicotiana benthamiana using agrobacterium tumefaciens. the same sequence was also cloned in antisense orientation. when self-pollinated progeny of 19 primary transformants were tested for resis ...	1996	8862407
the satellite rnas associated with the groundnut rosette disease complex and pea enation mosaic virus: sequence similarities and ability of each other's helper virus to support their replication.	pea enation mosaic virus (pemv) and the causal agents of groundnut rosette disease are diverse examples of disease complexes involving two rna species, one of which is related to the genomes of luteoviruses and the other to those of umbraviruses. in both complexes, these viral rna components may be supplemented with satellite rnas that are dependent on the umbravirus component for replication and systemic movement, and on the luteovirus component for encapsidation and vector transmission. sequen ...	1996	8922480
increased pathogenicity in a pseudorecombinant bipartite geminivirus correlates with intermolecular recombination.	most whitefly-transmitted geminiviruses possess bipartite dna genomes, and this feature may facilitate viral evolution through pseudorecombination and/or recombination. to test this hypothesis, the dna-a and dna-b components of the geminiviruses bean dwarf mosaic virus (bdmv) and tomato mottle virus (tomov) were exchanged, and the resultant pseudorecombinants were serially passaged through plants. both pseudorecombinants were infectious in nicotiana benthamiana but induced attenuated symptoms an ...	1996	8764054
expression of single-chain antibody fragments (scfv) specific for beet necrotic yellow vein virus coat protein or 25 kda protein in escherichia coli and nicotiana benthamiana.	the coding sequences for the variable regions of heavy and light chains of monoclonal antibodies (mabs) to beet necrotic yellow vein virus (bnyvv) coat protein (cp) or the 25 kda nonstructural protein (p25) were cloned into the pcock vector and expressed as single-chain antibody fragments (scfv) in escherichia coli. for expression in higher plants the scfv were targeted either to the secretory pathway by including the sequences encoding the pectate lyase b (pelb) or the phytohemagglutinin (pha) ...	1996	8980548
nla and nlb of peanut stripe potyvirus are present in the nucleus of infected cells, but do not form inclusions.	we investigated, by immunological and gene-fusion methods, whether the failure of peanut stripe potyvirus (pstv)-encoded nuclear inclusion proteins a (nla) and b (nlb) to form nuclear inclusions is due to the lack of their in vivo accumulation or the inability of one or both proteins to be transported into the nucleus nla domains (nla-vpg and nla-proteinase), full-length nlb, and full-length cylindrical inclusion (ci) protein of pstv were cloned, expressed in escherichia coli, and used for antis ...	1996	8874498
molecular cloning and functional expression of cdnas for glycyrrhiza glabra squalene synthase.	we have isolated two cdnas (ggsqs1 and ggsqs2) encoding squalene synthase of glycyrrhiza glabra l. by cross-hybridization with that of arabidopsis thaliana squalene synthase under conditions of low stringency. their nucleotide sequences contained an open reading frame for a polypeptide of 413 amino acids (ggsqs1) and 412 amino acids (ggsqs2), respectively. the deduced amino acid sequence of ggsqs1 exhibits 88%, 81%, 78%, 45-44%, and 45-41% identity to those of the ggsqs2, nicotiana benthamiana. ...	1996	8913521
tobamovirus cross protection using a potexvirus vector.	cross protection is the ability of one virus to prevent or delay infection by a related challenge virus. to examine this phenomena, a potato x potexvirus (pvx) vector (chapman et al., 1992, plant j. 2, 549) was used to systemically express the tobacco mosaic tobamovirus (tmv) coat protein (cp) open reading frame in nicotiana benthamiana. pvx constructs induce mild mosaic symptoms in n. benthamiana, whereas tmv infection results in rapid systemic necrosis and plant death. healthy plants or plants ...	1996	8955042
rna-mediated virus resistance: role of repeated transgenes and delineation of targeted regions.	resistance to cowpea mosaic virus (cpmv) in transgenic nicotiana benthamiana plants is rna mediated. in resistant cpmv movement protein (mp) gene-transformed lines, transgene steady state mrna levels were low, whereas nuclear transcription rates were high, implying that a post-transcriptional gene-silencing mechanism is at the base of the resistance. the silencing mechanism can also affect potato virus x (pvx) rnas when they contain cpmv mp gene sequences. in particular, sequences situated in th ...	1996	12239378
phloem unloading in sink leaves of nicotiana benthamiana: comparison of a fluorescent solute with a fluorescent virus.	using noninvasive imaging techniques, we compared phloem unloading of the membrane-impermeant, fluorescent solute carboxyfluorescein (cf) with that of potato virus x expressing the gene for the green fluorescent protein. although systemic virus transport took considerably longer to occur than did cf transport, unloading of both solute and virus occurred predominantly from the class iii vein network, a highly branched veinal system found between class ii veins. the minor veins (classes iv and v) ...	1997	12237387
kinetics of accumulation of citrus tristeza virus rnas.	citrus tristeza virus (ctv), a member of the closterovirus group, is one of the more complex single-stranded rna viruses. the 5' portion of its 19,296-nt, single-stranded rna genome is expressed as an approximately 400-kda polyprotein that is proteolytically processed, while the 10 3' open reading frames are expressed from 3'-coterminal subgenomic rnas (sg rnas). as an initial examination of the gene expression of this virus, we found that the kinetics of accumulation of genomic and sg rnas and ...	1997	9024813
biological properties of pseudorecombinant and recombinant strains created with cucumber mosaic virus and tomato aspermy virus.	cucumber mosaic virus (cmv) and tomato aspermy virus (tav) are closely related cucumoviruses. we have made pseudorecombinant viruses in which the rnas 3 of these two viruses have been exchanged and recombinant viruses containing chimeric rna 3 molecules, in which the coat proteins and the 3'-end regions of cmv and tav have been exchanged, giving rise to recombinants designated rt3 and tr3. the replication properties and the cell-to-cell and long-distance movement patterns of these pseudorecombin ...	1997	9094632
molecular analysis of the pothos latent virus genome.	pothos latent virus (polv) is an isometric virus with a positive-sense, single-stranded rna genome of 4415 nt. the genome contains five open reading frames (orf), coding for five proteins with approximate molecular masses of 25, 84, 40, 27 and 14 kda, respectively. in vitro synthesized polv rna was infectious to nicotiana benthamiana plants and protoplasts, but could not support replication of the defective interfering (di) and satellite rnas associated with cymbidium ringspot tombusvirus. no di ...	1997	9191911
complete nucleotide sequence of tobacco necrosis virus strain dh and genes required for rna replication and virus movement.	the complete genome sequence of tobacco necrosis virus strain d (hungarian isolate, tnv-dh) was determined. the genome (3762 nt) has an organization identical to that reported for tnv-d. highly infectious synthetic transcripts from a full-length tnv-dh cdna clone were prepared, the first infectious necrovirus transcript reported. this clone was used for reverse genetic studies to map the viral genes required for replication and movement. protoplast inoculation with delta 22 and delta 82 mutants ...	1997	9191913
replication of wild-type and mutant clones of satellite tobacco mosaic virus in nicotiana benthamiana protoplasts.	rna transcribed from cloned satellite tobacco mosaic virus (stmv) cdna replicated in nicotiana benthamiana protoplasts when co-inoculated with tobacco mild green mosaic virus (tmgmv) genomic rna, but degraded when inoculated alone. stmv genomic rna extracted from wild-type virions replicated in protoplasts when co-inoculated with tmgmv, tobacco mosaic virus (tmv) or tomato mosaic virus (tomv). transcripts from clones of two stmv coat protein (cp) mutants accumulated to the same level as wild-typ ...	1997	9191918
characterization of cucumber mosaic virus. iv. movement protein and coat protein are both essential for cell-to-cell movement of cucumber mosaic virus.	cdna clones of cucumber mosaic virus (cmv) rna 3 were modified to express the jellyfish green fluorescent protein (gfp) in place of the 3a movement protein (mp) or coat protein (cp), as fusions to the n (gfp-3a) or c (3a-gfp) terminus of the mp or from a separate open reading frame as part of tricistronic rnas 3. cmv rna transcripts containing the individual modified rnas 3 were unable to infect either nicotiana tabacum or nicotiana benthamiana systemically. infection, as measured by confocal mi ...	1997	9356336
new ribosome-inactivating proteins with polynucleotide:adenosine glycosidase and antiviral activities from basella rubra l. and bougainvillea spectabilis willd.	new single-chain (type 1) ribosome-inactivating proteins (rips) were isolated from the seeds of basella rubra l. (two proteins) and from the leaves of bougainvillea spectabilis willd. (one protein). these rips inhibit protein synthesis both in a cell-free system, with an ic50 (concentration causing 50% inhibition) in the 10(-10) m range, and by various cell lines, with ic50s in the 10(-8)-10(-6) m range. all three rips released adenine not only from rat liver ribosomes but also from escherichia ...	1997	9421927
engineering resistance against tomato yellow leaf curl virus (tylcv) using antisense rna.	one of the most severe diseases of cultivated tomato worldwide is caused by tomato yellow leaf curl virus (tylcv), a geminivirus transmitted by the whitefly bemisia tabaci. here we describe the application of antisense rnas to interfere with the disease caused by tylcv. the target of the antisense rna is the rare messenger rna of the rep protein, encoded by the c1 gene. transgenic nicotiana benthamiana plants expressing c1 antisense rna were obtained and shown to resist infection by tylcv. some ...	1997	9037152
susceptibility of peach gf 305 seedlings and selected herbaceous plants to plum pox virus isolates from western slovakia.	the susceptibility of peach gf 305 seedlings and herbaceous plants to five plum pox virus (ppv) isolates from orchards of western slovakia was investigated. ppv was isolated from diseased plum, apricot and peach trees, and transmitted by chip-budding to peach gf 305. the herbaceous plants were infected by mechanical inoculation. the transmission was analysed by symptomatology and double sandwich enzyme-linked immunosorbent assay (das-elisa). infected peaches developed leaf distortion, tissue cle ...	1997	9607094
transactivation of dianthin transgene expression by african cassava mosaic virus ac2.	we have recently described a novel strategy for engineering resistance to african cassava mosaic virus (acmv) in transgenic nicotiana benthamiana plants using a virus-inducible promoter to control the expression of a plant ribosome-inactivating protein (rip) transgene (y. hong et al., virology 220, 119-127, 1996). here, we have used a potato virus x (pvx) vector to express the acmv transactivator protein, ac2, in planta. we confirm that amplification of rip activity in transgenic plants is media ...	1997	9123846
genetic analysis of the monopartite tomato yellow leaf curl geminivirus: roles of v1, v2, and c2 orfs in viral pathogenesis.	tomato yellow leaf curl virus (tylcv) is a whitefly-transmitted geminivirus with a monopartite genome. we have investigated the functions of the v1, v2, and c2 orfs by mutational analysis. we analyzed the ability of tylcv mutants containing disrupted orfs v1, v2, or c2 to replicate, spread, and cause symptoms in nicotiana benthamiana and tomato plants. all the mutants retained the capability of autonomous replication in protoplast-derived cells of tomato and leaf discs of n. benthamiana, althoug ...	1997	9123819
regulation of a geminivirus coat protein promoter by al2 protein (trap): evidence for activation and derepression mechanisms.	tomato golden mosaic virus (tgmv) is a bipartite member of the subgroup iii geminiviridae. like all geminiviruses, tgmv replicates in the nucleus of susceptible cells by rolling circle replication (rcr). double-stranded replicative form dna generated during rcr serves as template for the transcription of viral genes by rna polymerase ii and the associated cellular transcription machinery. previous studies in tobacco protoplasts and nicotiana benthamiana leaf discs have shown that the viral al2 g ...	1997	9191840
molecular studies on bromovirus capsid protein. iii. analysis of cell-to-cell movement competence of coat protein defective variants of cowpea chlorotic mottle virus.	to determine whether the role of coat protein (cp) in cell-to-cell movement of dicot-adapted cowpea chlorotic mottle bromovirus (ccmv) is distinct from that of monocot-adapted brome mosaic bromovirus (bmv), two reporter genes, beta-glucuronidase (gus) and enhanced green fluorescent protein (egfp), were substituted for the cp in a biologically active clone of ccmv rna3 (c3). primary leaves of nicotiana benthamiana, chenopodium quinoa, and cowpea were co-inoculated with wild-type (wt) ccmv rna 1 a ...	1997	9191853
destabilization of potato spindle tuber viroid by mutations in the left terminal loop.	infectivity studies with highly infectious rna inocula generated by ribozyme cleavage were used to compare the biological properties of three apparently nonviable mutants of potato spindle tuber viroid (pstvd). one of these mutants (pstvd-p) contains three nucleotide substitutions in the left terminal loop, and mechanical inoculation of tomato seedlings with rna transcripts at levels equivalent to 10(3)-10(5) times the id50 for pstvd-intermediate failed to result in systemic infection. viable pr ...	1997	9191908
nontarget dna sequences reduce the transgene length necessary for rna-mediated tospovirus resistance in transgenic plants.	rna-mediated virus resistance has recently been shown to be the result of post-transcriptional transgene silencing in transgenic plants. this study was undertaken to characterize the effect of transgene length and nontarget dna sequences on rna-mediated tospovirus resistance in transgenic plants. transgenic nicotiana benthamiana plants were generated to express different regions of the nucleocapsid (n) protein of tomato spotted wilt (tswv) tospovirus. transgenic plants expressing half-gene segme ...	1997	9223349
the coat protein gene of grapevine leafroll associated closterovirus-3: cloning, nucleotide sequencing and expression in transgenic plants.	a lambda zap ii cdna library was constructed by cloning cdna prepared from a high molecular weight double-stranded rna (dsrna, ca. 18 kb) isolated from grapevine leafroll associated closterovirus-3 (glrav-3) infected tissues. this cdna library was immuno-screened with glrav-3 coat protein specific polyclonal and monoclonal antibodies and three immuno-positive clones were identified. analysis of nucleotide sequences from these clones revealed an open reading frame (orf) which was truncated at the ...	1997	9229001
molecular characterization of a subgroup i geminivirus from a legume in south africa.	a south african geminivirus for which we propose the name bean yellow dwarf virus (beydv) has been isolated from french bean (phaseolus vulgaris cv. bonus) showing stunting, chlorosis and leaf curl symptoms. a full-length cloned copy of the viral genome produced characteristic symptoms of the disease when reintroduced into french bean by agroinoculation, and was systemically infectious in nicotiana benthamiana, n. tabacum, lycopersicon esculentum, datura stramonium and arabidopsis thaliana. beyd ...	1997	9267015
suppression of potyvirus infection by coexpressed closterovirus protein.	a tobacco etch virus (tev)-based expression vector has been used for insertion of several orfs derived from the unrelated beet yellows virus (byv). hybrid tev variants expressing the byv capsid protein, 20-kda protein, or hsp70 homolog systemically infected nicotiana tabacum and stably retained byv sequences. in contrast, insertion of the orf encoding byv leader proteinase (l-pro) resulted in severely impaired systemic transport and accumulation of recombinant tev. progeny of this virus underwen ...	1997	9268155
host-controlled cell-to-cell movement of a hybrid barley stripe mosaic virus expressing a dianthovirus movement protein.	the triple gene block (tgb) of barley stripe mosaic virus (bsmv), coding for viral movement proteins (mps), was replaced by the single mp gene of red clover necrotic mosaic virus (rcnmv). accumulation of the hybrid virus in barley plants (the selective host for bsmv) was reduced compared to bsmv. the hybrid virus induced small necrotic local lesions on chenopodium amaranticolor leaves and did not infect nicotiana clevelandii (the selective host for rcnmv). the hybrid virus accumulated in the ino ...	1997	9268764
polygalacturonase-inhibiting proteins (pgips) with different specificities are expressed in phaseolus vulgaris.	the pgip-1 gene of phaseolus vulgaris, encoding a polygalacturonase-inhibiting protein (pgip), pgip-1 (p. toubart, a. desiderio, g. salvi, f. cervone, l. daroda, g. de lorenzo, c. bergmann, a. g. darvill, and p. albersheim, plant j. 2:367-373, 1992), was expressed under control of the cauliflower mosaic virus 35s promoter in tomato plants via agrobacterium tumefaciens-mediated transformation. transgenic tomato plants with different expression levels of pgip-1 were used in infection experiments w ...	1997	9304859
the enigma of px: a host-dependent cis-acting element with variable effects on tombusvirus rna accumulation.	tomato bushy stunt virus (tbsv) is a small isometric virus that contains a single-stranded rna genome with five major genes. in this study, we have analyzed the importance of an additional small sixth open reading frame (orf) of 207 nucleotides, designated px, which resides at the 3' end of the genome. bioassays showed that deletions or additions of nucleotides at the 5' end of the px gene that were designed to disrupt the orf, or site-specific inactivation of its start codon, all gave rise to t ...	1997	9344907
nicotiana benthamiana plants expressing beet necrotic yellow vein virus (bnyvv) coat protein-specific scfv are partially protected against the establishment of the virus in the early stages of infection and its pathogenic effects in the late stages of infection.	transgenic plants of nicotiana benthamiana expressing single chain antibody fragments (scfv) specific for the coat protein of beet necrotic yellow vein virus (bnyvv) and non-expressing control plants were inoculated with bnyvv mechanically and by means of the vector polymyxa betae. the scfv were presumably expressed in the endoplasmic reticulum (er). the average time needed for infections to become detectable was longer in the scfv-expressing plants than in the non-expressing control plants. in ...	1997	9672643
effects of temperature and host on the generation of tomato spotted wilt virus defective interfering rnas.	abstract the generation of defective interfering (di) rna molecules of tomato spotted wilt tospovirus (tswv) was studied by serially passaging in-ocula from plant to plant under different controlled conditions. di rnas were generated at higher rates in plants at 16 degrees c than in plants incubated at higher temperatures. another factor promoting the tswv di rna generation was the use of high virus concentrations in the inocula. the solanaceous species capsicum annuum, datura stramonium, lycope ...	1997	18945014
serological detection of grapevine virus a using antiserum to a nonstructural protein, the putative movement protein.	abstract grapevine virus a (gva) is implicated in the etiology of the rugose wood disease. the coat protein (cp) and the putative movement protein (mp) genes of gva were cloned and expressed in escherichia coli and used to produce antisera. both the cp and the mp were detected with their corresponding antisera in gva-infected nicotiana benthamiana. the mp was first detected at an early stage of the infection, 6 to 12 h after inoculation, and the cp was detected 2 to 3 days after inoculation. the ...	1997	18945038
novel defective interfering dnas associated with ageratum yellow vein geminivirus infection of ageratum conyzoides.	defective dna forms of the geminivirus ageratum yellow vein virus (ayvv) have been identified in naturally infected ageratum conyzoides plants. several examples of the defective dna have been cloned from purified virus-specific supercoiled dna and characterized by sequence analysis. all are approximately half the size of ayvv genomic dna, and all contain intergenic region sequences and the 5' terminus of gene c1 as well as additional sequences that are unrelated to the viral genomic dna. the chi ...	1997	9426449
specific inclusion bodies are associated with replication of lettuce infectious yellows virus rnas in nicotiana benthamiana protoplasts.	nicotiana benthamiana mesophyll protoplasts, either mock-inoculated or inoculated using in vitro transcripts derived from lettuce infectious yellows virus (liyv) rna 1- and/or rna 2-cloned cdnas were analysed by transmission electron microscopy (tem) and, in some cases, also by immunogold labelling. tem revealed the main cytopathological effects of liyv infections in n. benthamiana protoplasts infected with rnas 1 and 2: (a) typical closterovirus-induced (beet yellows virus-type) accumulations o ...	1998	9780036
beet yellows closterovirus hsp70-like protein mediates the cell-to-cell movement of a potexvirus transport-deficient mutant and a hordeivirus-based chimeric virus.	it has been suggested that the beet yellows closterovirus (byv)-encoded p65 protein, a homologue of hsp70 cell chaperones, plays a role as a virus movement protein (mp). to test this hypothesis, we used two types of complementation experiments with plant viruses containing the triple gene block (tgb) of mp genes. in one, the byv p65 gene was cloned into a 35s promoter plasmid and introduced into nicotiana benthamiana plants by microprojectile bombardment along with the 35s promoter-driven gus ge ...	1998	9568985
gene silencing from plant dna carried by a geminivirus.	the geminivirus tomato golden mosaic virus (tgmv) replicates in nuclei and expresses genes from high copy number dna episomes. the authors used tgmv as a vector to determine whether episomal dna can cause silencing of homologous, chromosomal genes. two markers were used to asses silencing: (1) the sulfur allele (su) of magnesium chelatase, an enzyme required for chlorophyll formation; and (2) the firefly luciferase gene (luc). various portions of both marker genes were inserted into tgmv in plac ...	1998	15494056
nonsense and missense translational suppression in plant cells mediated by trna(lys).	a nuclear trna(lys) gene from arabidopsis thaliana was cloned and mutated so as to express trnas with altered anticodons which bind to a uag nonsense (amber) codon and to the arg (agg), asn (aac,aat), gln (cag) or glu (gag) codons. concomitantly, a codon in the firefly luciferase gene for a functionally important lys was altered to an amber codon, or to arg, asn, gln, glu, thr and trp codons, so as to construct reporter genes reliant upon incorporation of lys. the altered trna(lys) and luciferas ...	1998	9484471
resistance of nicotiana benthamiana to phytophthora infestans is mediated by the recognition of the elicitor protein inf1	phytophthora infestans, the agent of potato and tomato late blight disease, produces a 10-kd extracellular protein, inf1 elicitin. inf1 induces a hypersensitive response in a restricted number of plants, particularly those of the genus nicotiana. in virulence assays with different p. infestans isolates, five nicotiana species displayed resistance responses. in all of the interactions, after inoculation with p. infestans zoospores, penetration of an epidermal cell was observed, followed by locali ...	1998	9724689
molecular and serological characterization of iris yellow spot virus, a new and distinct tospovirus species.	abstract a new tospovirus was identified in iris cultivations in the netherlands. both serological comparisons and sequence determination of the s rna demonstrate that this virus represents a new and distinct species, belonging to a separate serogroup, and for which the name iris yellow spot virus (iysv) is proposed. the disease symptoms on iris are characterized by yellow spots on the leaves. its experimental host range is very narrow and, in addition to iris, only includes nicotiana benthamian ...	1998	18944829
replication specificity elements of the worland strain of beet curly top virus are compatible with those of the cfh strain but not those of the cal/logan strain.	abstract cloned genomes of the cfh, worland, and cal/logan strains of beet curly top virus (bctv) served as helper viruses to trans-replicate defective (d) dnas that are incapable of self-replication due to deletions within the c1 open reading frame encoding the replication initiator (rep) protein. the logan rep protein could trans-replicate a logan-derived d dna in a transient replication assay conducted in nicotiana benthamiana leaf disks. however, the logan rep protein was unable to trans-rep ...	1998	18944850
defective movement of viruses in the family bromoviridae is differentially complemented in nicotiana benthamiana expressing tobamovirus or dianthovirus movement proteins.	abstract taxonomically distinct tobacco mosaic tobamovirus (tmv), red clover necrotic mosaic dianthovirus (rcnmv), cucumber mosaic cucumovirus (cmv), brome mosaic bromovirus (bmv), and cowpea chlorotic mottle bromovirus (ccmv) exhibit differences in their host range. each of these viruses encodes a functionally similar nonstructural movement protein (mp) that is essential for cell-to-cell movement of a progeny virus. despite the lack of significant amino acid identity among the mps of cmv, tmv, ...	1998	18944938
comparison of ambisense m rna of watermelon silver mottle virus with other tospoviruses.	abstract double-stranded genomic rnas (dsrnas) extracted from chenopodium quinoa infected with watermelon silver mottle virus (wsmv) were similar to those of tomato spotted wilt virus (tswv, serogroup i) and impatiens necrotic spot virus (insv, serogroup iii), except that the s dsrna of wsmv is 0.75 and 0.6 kbp longer than those of tswv and insv, respectively. the complete nucleotide sequence of the genomic m rna of wsmv was determined from cdna clones generated from separated m dsrna. the m rna ...	1998	18944959
evolution of bamboo mosaic virus in a nonsystemic host results in mutations in the helicase-like domain that cause reduced rna accumulation.	a mutant population of bamboo mosaic potexvirus (bamv) was isolated after serial passage using chenopodium quinoa plants. while the wild type inoculum induced indistinct chlorotic lesions, the mutant produced obvious lesions on c. quinoa although rna accumulation of the mutant in nicotiana benthamiana protoplasts was significantly reduced compared to wild type. mutations were identified in the helicase-like domain. one rt-pcr-generated cdna clone (designated pl1-33) representing the helicase-lik ...	1998	9879769
tobacco mosaic virus infection induces severe morphological changes of the endoplasmic reticulum.	the tobacco mosaic virus (tmv) movement protein (mp) facilitates transport of virus infection between adjacent cells by modifying plasmodesmata. previous studies suggested that the cytoskeleton and the endomembrane system are involved in this transport. we examined the effects of tmv infection on the endoplasmic reticulum (er) in transgenic nicotiana benthamiana that accumulate the green fluorescent protein (gfp) in the er. fluorescence microscopy was used to show that early in infection the er ...	1998	9736708
mutational analysis of bean yellow dwarf virus, a geminivirus of the genus mastrevirus that is adapted to dicotyledonous plants.	bean yellow dwarf virus (beydv) is an atypical member of the geminivirus genus mastrevirus that infects dicotyledonous plants. beydv dna contains six open reading frames (orfs) with the capacity to encode proteins in excess of 10 kda. two virion-sense orfs (v1 and v2) and two complementary-sense orfs (c1 and c2) have homologues in all mastreviruses, while orfs c3 and c4 are not conserved. to investigate their functions, each of the orfs has been truncated by either frame-shifting or the introduc ...	1998	9747737
havana tomato virus, a new bipartite geminivirus infecting tomatoes in cuba.	the cloning and nucleotide sequence of a new bipartite geminivirus found in cuba is described. dna a (2620 nt) and dna b (2586 nt) presented a genomic structure resembling that of other geminiviruses transmitted by bemisia tabaci. both components had a common region of 168 nt with a 95% identity. typical elements involved in replication and transcription were found in this region, though group-characteristic arrangement of iterons was not conserved in this virus. sequence was compared with gemin ...	1998	9787659
asymmetric infectivity of pseudorecombinants of cabbage leaf curl virus and squash leaf curl virus: implications for bipartite geminivirus evolution and movement.	the bipartite geminiviruses squash leaf curl virus (sqlcv) and cabbage leaf curl virus (clcv) have distinct host ranges. sqlcv infects a broad range of plants within the cucurbitaceae, including pumpkin and squash, and clcv has a broad host range within brassicaceae that includes cabbage and arabidopsis thaliana. despite this, the genomic a components of these viruses share a high degree of sequence identity, particularly in the gene encoding the replication protein al1, and their common regions ...	1998	9792839
amino acids in the capsid protein of tomato yellow leaf curl virus that are crucial for systemic infection, particle formation, and insect transmission.	a functional capsid protein (cp) is essential for host plant infection and insect transmission in monopartite geminiviruses. we studied two defective genomic dnas of tomato yellow leaf curl virus (tylcv), sic and sicrcv. sic, cloned from a field-infected tomato, was not infectious, whereas sicrcv, which spontaneously originated from sic, was infectious but not whitefly transmissible. a single amino acid change in the cp was found to be responsible for restoring infectivity. when the amino acid s ...	1998	9811744
viral pathogenicity determinants are suppressors of transgene silencing in nicotiana benthamiana.	post-transcriptional gene silencing (ptgs) of a green fluorescent protein (gfp) transgene is suppressed in nicotiana benthamiana plants infected with potato virus y (pvy) or with cucumber mosaic virus (cmv), but not in plants infected with potato virus x (pvx). by expressing pvy and cmv-encoded proteins in a pvx vector we have shown that the viral suppressors of gene silencing are the hcpro of pvy and the 2b protein of cmv. the hcpro acts by blocking the maintenance of ptgs in tissues where sile ...	1998	9822616
genetic determinants of host-specificity in bipartite geminivirus dna a components.	geminiviruses are small, ssdna-containing plant viruses. bean golden mosaic virus (bgmv) and tomato golden mosaic virus (tgmv) have bipartite genomes, the components of which are designated a and b. although they are closely related, bgmv and tgmv nevertheless exhibit distinct host-specific phenotypes, with bgmv being well adapted to beans and tgmv being well adapted to nicotiana benthamiana. a previous study showed that the two open reading frames (orfs) of dna b only partially determine the ho ...	1998	9837800
molecular studies on bromovirus capsid protein.	brome mosaic bromovirus (bmv) and cucumber mosaic cucumovirus (cmv) are structurally and genetically very similar. the specificity of the bmv and cmv coat proteins (cps) during in vivo encapsidation was studied using two rna3 chimera in which the respective cp genes were exchanged. the replicative competence of each chimera was analyzed in nicotiana benthamiana protoplasts, and their ability to cause infections was examined in two common permissive hosts, chenopodium quinoa and n. benthamiana. e ...	1998	9837807
expression and assembly of a full-length monoclonal antibody in plants using a plant virus vector.	we have used a tobacco mosaic virus-based vector to express monoclonal antibody (mab) co17-1a, directed to a colon cancer antigen, in plants. genes encoding heavy and light chains of this antibody were introduced independently into the tobacco mosaic virus vector. upon co-infection of nicotiana benthamiana plants with both recombinant virus constructs, genes for heavy and light chains were expressed and assembled into a full-length antibody. a functional plant-expressed antibody was detected by ...	1998	9839927
expression of an anther-specific chalcone synthase-like gene is correlated with uninucleate microspore development in nicotiana sylvestris.	two cdna clones, specifically expressed in nicotiana sylvestris anthers during uninucleate microspore development, were isolated using a subtractive hybridization approach. sequence analysis showed that one of them, nschslk, displayed a high level of similarity to several anther-specific chalcone synthase-like (chslk) proteins and an orf from chromosome i of arabidopsis thaliana. a lower, but significant, similarity to chalcone synthases and closely related enzymes (chsre) was also detected. the ...	1998	9869422
specific sequence changes in the 5'-terminal region of the genome of satellite tobacco mosaic virus are required for adaptation to tobacco mosaic virus.	the genome of satellite tobacco mosaic virus (stmv) adapted to tobacco mosaic virus (tmv), tomato mosaic virus or green tomato atypical mosaic virus consistently had two single base deletions at positions 1 and 61, corresponding to bases a and g, respectively, as compared to the type-strain genome which is naturally adapted to tobacco mild green mosaic virus (tmgmv). transcript rnas (stmv(tmv)) from clone pstmv(tmv) which captured the deletions at positions 1 and 61 were infectious when co-inocu ...	1998	9568987
coat protein interactions involved in tobacco mosaic tobamovirus cross-protection.	to investigate the molecular role of the tobacco mosaic tobamovirus (tmv) coat protein (cp) in conferring cross-protection, a potato x potexvirus (pvx) vector (s. chapman, plant j. 2, 549-557, 1992) was used to systemically express a set of tmv mutant cps in nicotiana benthamiana prior to challenge inoculation with tmv. pvx-expressed wild-type tmv cp delayed tmv accumulation for up to 2 weeks compared to unprotected plants or plants preinfected with the unmodified pvx vector. similar delays in t ...	1998	9721228
identification of genes involved in replication and movement of peanut clump virus.	the genome of peanut clump pecluvirus (pcv) consists of two messenger rna components which contain, respectively, three and five open reading frames (orfs). inoculation of transcripts from full-length cdna clones derived from the pcv rnas showed that rna-1 is able to replicate in the absence of rna-2 in protoplasts, but both rnas are necessary for plant infection. to investigate the role of different gene products in viral rna replication and movement, transcripts from mutant cdna clones were in ...	1998	9721240
deletions in the conserved amino-terminal basic arm of cucumber mosaic virus coat protein disrupt virion assembly but do not abolish infectivity and cell-to-cell movement.	the n-terminal basic arm of cucumber mosaic cucumovirus (cmv) coat protein (cp) contains a conserved arginine-rich motif, which is characteristic of rna binding proteins of several plant and nonplant viruses. to identify regions of the cmv cp n-terminus that are essential for interacting with viral genomic rna, a comprehensive set of mutations was engineered into biologically active clones of cmv rna3 and the behavior of each variant with respect to infectivity, packaging and movement was examin ...	1998	9721241
evolution of a quadripartite hybrid virus by interspecific exchange and recombination between replicase components of two related tripartite rna viruses.	cucumber mosaic virus (cmv) and tomato aspermy virus (tav) belong to the cucumovirus genus. they have a tripartite genome consisting of single-stranded rnas, designated 1, 2, and 3. previous studies have shown that viable pseudorecombinants could be created in vitro by reciprocal exchanges between cmv and tav rna 3, but exchanges of rnas 1 and 2 were replication deficient. when we coinoculated cmv rnas 2 and 3 along with tav rnas 1 and 2 onto nicotiana benthamiana, a hybrid quadripartite virus a ...	1998	9724730
membrane targeting sequences in tombusvirus infections.	infection of nicotiana benthamiana cells with cymbidium ringspot (cymrsv) and carnation italian ringspot (cirv) viruses results in the formation of conspicuous membranous bodies [multivesicular bodies (mvbs)], which develop from modified peroxisomes or mitochondria, respectively. the organelle targeting signal is located in the proteins of 33 kda (cymrsv) or 36 kda (cirv) encoded by orf 1, which contain an n-terminal hydrophilic portion followed by two predicted hydrophobic transmembrane segment ...	1998	9878622
construction of full-length cdna clones of lettuce mosaic virus (lmv) and the effects of intron-insertion on their viability in escherichia coli and on their infectivity to plants.	a full length cdna copy of the genomic rna of lettuce mosaic virus (lmv) was constructed under the control of an enhanced camv 35s promoter and of the nos terminator. this construct was found infectious when inoculated to lettuce plants. the intron ii of the bean nitrite reductase gene was engineered into the lmv fl cdna in order to relieve possible deleterious effects of viral sequences to escherichia coli cells and to evaluate the effects of the presence of the intron on the fl cdna infectivit ...	1998	9930200
strain variability of plum pox virus isolates from western slovakia.	leaf tissues of stone fruit trees (plum, apricot, peach and myrobalan) carrying symptoms of plum pox virus (ppv) infection and of peach gf 305 seedlings and nicotiana benthamiana infected experimentally with ppv were assayed for ppv by polymerase chain reaction (pcr). the expected 243 bp pcr products were subjected to restriction fragment length polymorphism (rflp) analysis with restriction endonucleases alui and rsai. all of the pcr products contained the alui site. the rsai restriction profile ...	1998	9770072
nicotiana benthamiana plants transformed with the plum pox virus helicase gene are resistant to virus infection.	nicotiana benthamiana domin. plants were transformed with the cytoplasmic inclusion protein (ci) gene of plum pox potyvirus (ppv) to investigate, whether this non-structural protein would be able to confer resistance. the ci protein is an rna helicase, which contains a conserved nucleotide binding motif (ntbm) and plays an important role in viral replication. two gene constructions were developed for plant transformation. the first contains the original coding sequence of the ci gene under the c ...	1998	9617773
use of modified plum pox virus coat protein genes developed to limit heteroencapsidation-associated risks in transgenic plants.	aphid transmission of a non-aphid-transmissible strain of zucchini yellow mosaic virus (zymv-nat) occurs in transgenic plants expressing the plum pox potyvirus (ppv) coat protein (cp) gene. heteroencapsidation has been shown to be responsible for this modification in the epidemiological characteristics of the infecting virus. in order to prevent this biological risk, several modified ppv cp constructs were produced that were designed to interfere with heteroencapsidation itself or to block aphid ...	1998	9634095
molecular characterization of tobacco squalene synthase and regulation in response to fungal elicitor.	the enzyme squalene synthase (ss) represents the first commitment of carbon from the general isoprenoid pathway toward sterol biosynthesis and is a potential point for regulation of sterol biosynthesis. the isolation and characterization of tobacco (nicotiana tabacum) squalene synthase (tss) cdna and genomic dna clones, as well as determination of the steady state level of tss mrna in response to elicitor treatment, were investigated. cdna clones for tss were isolated from poly (a)+ rna using a ...	1998	9448707
charge changes near the n terminus of the coat protein of two potyviruses affect virus movement.	mutants of tobacco vein mottling virus (tvmv) with substitutions of lys or arg for asp in the dag motif at position 5 in the coat protein (cp) failed to infect tobacco plants systemically, but replicated and produced virions in protoplasts. occasional systemic infections occurred when nicotiana benthamiana or transgenic tobacco plants expressing wild-type tvmv cp were inoculated with these mutants, but viral progeny contained reversions to negatively or non-charged amino acids at position 5 or s ...	1998	9460938
the movement protein and coat protein of alfalfa mosaic virus accumulate in structurally modified plasmodesmata.	in systemically infected tissues of nicotiana benthamiana, alfalfa mosaic virus (amv) coat protein (cp) and movement protein (mp) are detected in plasmodesmata in a layer of three to four cells at the progressing front of infection. besides the presence of these viral proteins, the plasmodesmata are structurally modified in that the desmotubule is absent and the diameter has increased drastically (almost twofold) when compared to plasmodesmata in uninfected cells or cells in which amv infection ...	1998	9601503
recombination between viral dna and the transgenic coat protein gene of african cassava mosaic geminivirus.	nicotiana benthamiana was transformed with three different constructs (pcra1, pcra2 and pjc1) containing the coat protein coding sequence of african cassava mosaic virus (acmv). transformed plants were inoculated with a coat protein deletion mutant of acmv that induces mild systemic symptoms in control plants. several inoculated plants of transgenic lines cra1/3, cra1/4, cra2/1 and cra2/2 developed severe systemic symptoms typical of acmv. dna analysis revealed that, in these plants, recombinati ...	1998	9603342
a dna clone encoding the full-length infectious genome of odontoglossum ringspot tobamovirus and mutagenesis of its coat protein gene.	a full-length dna clone encoding the genome of odontoglossum ringspot tobamovirus (orsv) was synthesized and placed adjacent to a bacteriophage t7 rna polymerase promoter. capped-rna transcripts produced in vitro were highly infectious when mechanically inoculated onto seedlings of nicotiana benthamiana and oncidium gower ramsey. a representative clone, designated pot2, caused a disease phenotype identical to that produced by parental viral rna. elisa, western blot analysis, northern blot hybrid ...	1998	9505974
intracellular location of two groundnut rosette umbravirus proteins delivered by pvx and tmv vectors.	the proteins encoded by open reading frames (orf) 3 and 4 of groundnut rosette umbravirus (grv) were expressed in nicotiana benthamiana as fusions with green fluorescent protein (gfp) from modified potato virus x (pvx) and tobacco mosaic virus (tmv) vectors. regardless of which plant virus vector was used, gfp fused to the orf3 protein accumulated in large cytoplasmic inclusion bodies and in nucleoli, whereas gfp fused to the orf4 protein was found in cell walls close to plasmodesmata. cell-to-c ...	1998	9514976
mutations in viral movement protein alter systemic infection and identify an intercellular barrier to entry into the phloem long-distance transport system.	viral systemic infection of a plant host involves two processes, cell-to-cell movement and long-distance transport. molecular determinants associated with these two processes were probed by investigating the effects that alanine scanning mutations in the movement protein (mp) of red clover necrotic mosaic virus (rcnmv) had on viral infection in the plant hosts nicotiana edwardsonii, vigna unguiculata (cowpea), and the experimental plant nicotiana benthamiana. plants were inoculated with rcnmv ex ...	1998	9614869
the use of dig-labelled crna probes for the detection of cymbidium mosaic potexvirus (cymmv) and odontoglossum ringspot tobamovirus (orsv) in orchids.	dig-labelled sense and antisense crna probes were synthesized from cdna clones of cymmv and orsv for virus detection in infected plants. a slot-blot hybridization assay was developed using either crude leaf extracts or total rna from infected leaves. the assay could detect 50 and 250 pg of purified cymmv and orsv rna, respectively. as little as 30 mg of nicotiana benthamiana infected leaves was sufficient to provide positive detection. cymmv and orsv were detected at 3125 and 625 times dilution ...	1998	9562413
initiation and maintenance of virus-induced gene silencing	the phytoene desaturase (pds) gene of nicotiana benthamiana was silenced in plants infected with potato virus x (pvx) vectors carrying pds inserts, and a green fluorescent protein (gfp) transgene was silenced in plants infected with pvx-gfp. this virus-induced gene silencing (vigs) is post-transcriptional and cytoplasmic because it is targeted against exons rather than introns of pds rna and against viral rnas. although pds and gfp rnas are most likely targeted through the same mechanism, the vi ...	1998	9634582
characterization of cucumber mosaic virus. v. cell-to-cell movement requires capsid protein but not virions.	to ascertain the importance of amino-terminal proximal capsid protein (cp) sequences in cel-to-cell movement, virion formation, and stabilization, two cp mutants of cucumber mosaic virus (cmv) were generated by deletion of sequences encoding cp amino acids 15-40 (delta sal-nru) or 26-40 (delta sac-nru). wildtype cmv and cmv containing delta sac-nru could infect systemically four host species, although symptoms induced by the two viruses usually were different cmv containing delta sal-nru could o ...	1998	9657941
changing patterns of localization of the tobacco mosaic virus movement protein and replicase to the endoplasmic reticulum and microtubules during infection.	tobacco mosaic virus (tmv) derivatives that encode movement protein (mp) as a fusion to the green fluorescent protein (mp:gfp) were used in combination with antibody staining to identify host cell components to which mp and replicase accumulate in cells of infected nicotiana benthamiana leaves and in infected by-2 protoplasts. mp:gfp and replicase colocalized to the endoplasmic reticulum (er; especially the cortical er) and were present in large, irregularly shaped, er-derived structures that ma ...	1998	9668131
high resistance and control of biological risks in transgenic plants expressing modified plum pox virus coat protein.	transgenic plums transformed with the plum pox virus coat protein (ppv cp) gene displayed a resistance to the sharka disease (ravelonandro et al., 1997). however, the expression of ppv cp in transgenic plants may lead to complementation of deficient characteristic of an incoming potyvirus. indeed, an aphid-intransmissible strain of zucchini yellow mosaic virus (zymv-nat) could be transmitted when encapsidated by the engineered ppv cp (lecoq et al., 1993). to control such a risk, new ppv cp const ...	1998	10073226
plum pox potyvirus resistance associated to transgene silencing that can be stabilized after different number of plant generations.	nicotiana benthamiana plants were transformed with a fragment of the plum pox potyvirus (ppv) genome that encodes the nuclear inclusion a (nia) and b (nib) proteins and the n-terminus of the capsid protein (nia-nib-cp). lines transformed with this ppv genomic fragment harboring mutations in the gdd replicase-motif were also obtained. plants of niadeltav lines that carry a gdd to vdd mutation in the ppv transgene, were immune to ppv infection. the resistance was highly specific, since it was only ...	1998	9469941
the role of abi1 in abscisic acid signal transduction: from gene to cell.	the semi-dominant abi1-1 mutation of arabidopsis interferes with multiple aspects of abscisic acid signal transduction resulting in reduced seed dormancy and sensitivity of root growth in aba. furthermore, the mutant transpires excessively as a result of abnormal stomatal regulation leading to a wilty phenotype. the abi1 gene has been cloned. the carboxyl-terminal domain of the predicted abi1 protein is related to the 2c class of serine-threonine phosphatases while no overt homology was found in ...	1998	10645425
turnip mosaic potyvirus resistance in nicotiana benthamiana derived by post-transcriptional gene silencing.	the coat protein (cp) gene of turnip mosaic potyvirus isolate esc8 (tumv-esc8) was cloned and sequenced. comparisons of the 867-nucleotide (nt) cp region with those of 11 tumv isolates showed 86.7-89.3% nucleotide identity and 92.4-95.5% amino acid identity. the cp gene was cloned into a plant expression vector and transformed into nicotiana benthamiana plants via agrobacterium tumefaciens-mediated leaf disk transformation. progeny from r0 lines was screened for resistance to tumv-esc8. five of ...	1999	10478490
interactions between tombusviruses and satellite rnas of tomato bushy stunt virus: a defect in sat rna b1 replication maps to orf1 of a helper virus.	the biological properties of two recently described satellite rnas of tomato bushy stunt virus (tbsv) were analyzed in natural and experimental hosts. full-length cdna clones were constructed for sat rnas b1(822 nt) and b10 (612 nt) and used in inoculations with satellite-free transcripts of different tombusviruses. in all virus-host combinations tested, tbsv sat rna b10 drastically reduced the accumulation of viral genomic rna and attenuated symptoms. in contrast, sat rna b1 caused a less marke ...	1999	10489347
expression of the bs2 pepper gene confers resistance to bacterial spot disease in tomato.	the bs2 resistance gene of pepper specifically recognizes and confers resistance to strains of xanthomonas campestris pv. vesicatoria that contain the corresponding bacterial avirulence gene, avrbs2. the involvement of avrbs2 in pathogen fitness and its prevalence in many x. campestris pathovars suggests that the bs2 gene may be durable in the field and provide resistance when introduced into other plant species. employing a positional cloning strategy, the bs2 locus was isolated and the gene wa ...	1999	10570214
internal initiation of translation directed by the 5'-untranslated region of the tobamovirus subgenomic rna i(2).	previously we reported that, unlike rna of typical tobamoviruses, the translation of the coat protein (cp) gene of a crucifer-infecting tobamovirus (crtmv) in vitro occurred by an internal ribosome entry mechanism mediated by the 148-nt region that contained an internal ribosome entry site (ires(cp,148)(cr)). the equivalent 148-nt sequence from tmv u1 rna (u1(cp,148)(sp)) was incapable of promoting internal initiation. in the present work, we have found that the 228-nt region upstream of the mov ...	1999	10544089
infectious rna transcripts from grapevine virus a cdna clone.	a full length cdna clone of grapevine virus a (gva) was constructed downstream from the bacteriophage t7 rna polymerase promoter. capped in vitro-transcribed rna was infectious in nicotiana benthamiana and n. clevelandii plants. symptoms induced by the rna transcripts or by the parental virus were indistinguishable. the infectivity of the in vitro-transcribed rna was confirmed by serological detection of the virus coat and movement proteins and by observation of virions by electron microscopy. t ...	1999	10595415
mitotic stability of infection-induced resistance to plum pox potyvirus associated with transgene silencing and dna methylation.	plum pox potyvirus (ppv) infection of transgenic nicotiana benthamiana plants that expressed the ppv nib rna replicase carrying a gly to val mutation at the gdd motif (nibv lines) induced a phenotype of virus resistance and transgene silencing, which was not transmissible to the progeny after self-fertilization (h. s. guo and j. a. garcía, mol. plant-microbe interact. 10:160-170, 1997). here, we demonstrate that the induced resistance of nibv plants is mitotically stable after plant propagation ...	1999	9926412
restoration of wild-type virus by double recombination of tombusvirus mutants with a host transgene.	nicotiana benthamiana plants transformed with the coat protein gene of tomato bushy stunt virus (tbsv) failed to elicit effective virus resistance when inoculated with wildtype virus. subsequently, r1 and r2 progeny from 13 transgenic lines were inoculated with a tbsv mutant containing a defective coat protein gene. mild symptoms typical of those elicited in nontransformed plants infected with the tbsv mutant initially appeared. however, within 2 to 4 weeks, up to 20% of the transgenic plants sp ...	1999	9926415
expression of alfalfa mosaic virus coat protein in tobacco mosaic virus (tmv) deficient in the production of its native coat protein supports long-distance movement of a chimeric tmv.	alfalfa mosaic virus (almv) coat protein is involved in systemic infection of host plants, and a specific mutation in this gene prevents the virus from moving into the upper uninoculated leaves. the coat protein also is required for different viral functions during early and late infection. to study the role of the coat protein in long-distance movement of almv independent of other vital functions during virus infection, we cloned the gene encoding the coat protein of almv into a tobacco mosaic ...	1999	10051680
sufficient length of a poly(a) tail for the formation of a potential pseudoknot is required for efficient replication of bamboo mosaic potexvirus rna.	rnas transcribed from a full-length infectious cdna clone of the bamboo mosaic potexvirus (strain o) genome, pbamv-o, were infectious to nicotiana benthamiana plants. mutant genomes in which the poly(a) tail is absent or replaced by a 3' trna-like structure from turnip yellow mosaic virus rna failed to amplify detectably in n. benthamiana protoplasts. no amplification was detected in protoplasts inoculated with transcripts containing 4, 7, or 10 adenylate residues at the 3' end, whereas transcri ...	1999	10074116
the 5' noncoding region of grapevine chrome mosaic nepovirus rna-2 triggers a necrotic response on three nicotiana spp.	the 5' noncoding region (ncr) of grapevine chrome mosaic nepovirus (gcmv) was cloned in a viral vector derived from potato virus x (pvx). the recombinant virus obtained was inoculated to nicotiana benthamiana, n. clevelandii, and n. tabacum plants. infected plants developed necrotic symptoms in place of the vein clearing and mosaic typically observed after inoculation with pvx. northern (rna) blot analysis showed that the replication of pvx was not specifically altered by the presence of the gcm ...	1999	10188272
bean yellow dwarf virus repa, but not rep, binds to maize retinoblastoma protein, and the virus tolerates mutations in the consensus binding motif.	it has previously been reported that complementary-sense gene products of wheat dwarf virus (wdv), a geminivirus of the genus mastrevirus that infects monocotyledonous plants, bind to human and maize retinoblastoma (rb) protein. rb proteins control cell-cycle progression by sequestering transcription factors required for entry into s-phase, suggesting that the virus modifies the cellular environment to produce conditions suitable for viral dna replication. using a yeast two-hybrid assay, we have ...	1999	10191192
the specificity of polygalacturonase-inhibiting protein (pgip): a single amino acid substitution in the solvent-exposed beta-strand/beta-turn region of the leucine-rich repeats (lrrs) confers a new recognition capability.	two members of the pgip gene family (pgip-1 and pgip-2) of phaseolus vulgaris l. were expressed separately in nicotiana benthamiana and the ligand specificity of their products was analysed by surface plasmon resonance (spr). polygalacturonase-inhibiting protein-1 (pgip-1) was unable to interact with pg from fusarium moniliforme and interacted with pg from aspergillus niger; pgip-2 interacted with both pgs. only eight amino acid variations distinguish the two proteins: five of them are confined ...	1999	10228150
functional expression in bacteria and plants of an scfv antibody fragment against tospoviruses.	recombinant antibodies expressed in plants ('plantibodies'), directed against crucial antigens and addressed to the right cell compartment, may be able to protect against viral diseases. moreover, antibody fragments produced in bacteria or plants may provide low cost reagents for immunodiagnosis.	1999	10231089
a nanovirus-like dna component associated with yellow vein disease of ageratum conyzoides: evidence for interfamilial recombination between plant dna viruses.	yellow vein disease of ageratum conyzoides, a weed species that is widely distributed throughout asia, has been attributed to infection by the geminivirus ageratum yellow vein virus (ayvv). in addition to a single ayvv genomic component (dna a), we have previously demonstrated that infected plants contain chimeric defective viral components, comprising dna a and nongeminiviral sequences, that act as defective interfering dnas. a database search has revealed that the nongeminiviral sequences of o ...	1999	10544139
the first triple gene block protein of peanut clump virus localizes to the plasmodesmata during virus infection.	the subcellular localization of the first triple gene block protein (tgbp1) of peanut clump pecluvirus (pcv) was studied by subcellular fractionation and immunogold cytochemistry using tgbp1-specific antibodies raised against a fusion protein expressed in and purified from bacteria. in the inoculated and apical leaves of virus-infected nicotiana benthamiana, tgbp1 localized to the cell wall and p30 fractions. electron microscopy of immunogold-decorated ultrathin sections of the infected leaf tis ...	1999	10544148
nonstructural proteins of tobacco rattle virus which have a role in nematode-transmission: expression pattern and interaction with viral coat protein.	rna 2 of tobacco rattle virus isolate ppk20 encodes the viral coat protein (cp) and two nonstructural proteins of 40 kda ('40k protein') and 32.8 kda ('32.8k'). the 40k protein is required for transmission of the virus by the vector nematode paratrichodorus pachydermus whereas the 32.8k protein may be involved in transmission by other vector nematode species. an antiserum was raised against the 40k protein expressed in e. coli and used to study the expression and subcellular localization of this ...	1999	10567661
suppression of gene silencing: a general strategy used by diverse dna and rna viruses of plants.	in transgenic and nontransgenic plants, viruses are both initiators and targets of a defense mechanism that is similar to posttranscriptional gene silencing (ptgs). recently, it was found that potyviruses and cucumoviruses encode pathogenicity determinants that suppress this defense mechanism. here, we test diverse virus types for the ability to suppress ptgs. nicotiana benthamiana exhibiting ptgs of a green fluorescent protein transgene were infected with a range of unrelated viruses and variou ...	1999	10570213
broad-spectrum protection against tombusviruses elicited by defective interfering rnas in transgenic plants.	we have designed a dna cassette to transcribe defective interfering (di) rnas of tomato bushy stunt virus (tbsv) and have investigated their potential to protect transgenic nicotiana benthamiana plants from tombusvirus infections. to produce rnas with authentic 5' and 3' termini identical to those of the native b10 di rna, the di rna sequences were flanked by ribozymes (rzdi). when rzdi rnas transcribed in vitro were mixed with parental tbsv transcripts and inoculated into protoplasts or plants, ...	1999	10233970
alfalfa mosaic virus rnas serve as cap donors for tomato spotted wilt virus transcription during coinfection of nicotiana benthamiana.	tomato spotted wilt virus (tswv) was shown to use alfalfa mosaic virus (amv) rnas as cap donors in vivo during a mixed infection in nicotiana benthamiana. by use of nested reverse transcription-pcr, tswv n and nss mrnas provided with capped leader sequences derived from all four amv rnas could be cloned and sequenced. the sequence specificity of the putative tswv endonuclease involved is discussed.	1999	10233983
strong host resistance targeted against a viral suppressor of the plant gene silencing defence mechanism.	the 2b protein encoded by cucumber mosaic cucumovirus (cmv2b) acts as an important virulence determinant by suppressing post-transcriptional gene silencing (ptgs), a natural plant defence mechanism against viruses. we report here that the tomato aspermy cucumovirus 2b protein (tav2b), when expressed from the unrelated tobacco mosaic tobamovirus (tmv) rna genome, activates strong host resistance responses to tmv in tobacco which are typical of the gene-for-gene disease resistance mechanism. domai ...	1999	10329615
subcellular localization and in vivo identification of the putative movement protein of olive latent virus 2.	the gene encoding the 36.5 kda ('36k') nonstructural protein located on rna3 of olive latent virus 2 (olv-2) was cloned, expressed with the escherichia coli pgex-2t system and the purified protein used to raise a polyclonal antiserum. immunoblot analysis of olv-2-infected nicotiana benthamiana plants showed that the 36k protein accumulated in the early stages of infection and was associated with a subcellular fraction enriched in cytoplasmic membranes. in infected cells there were tubular struct ...	1999	10355755