| the mi-1-mediated pest resistance requires hsp90 and sgt1. | the tomato (solanum lycopersicum) mi-1 gene encodes a protein with putative coiled-coil nucleotide-binding site and leucine-rich repeat motifs. mi-1 confers resistance to root-knot nematodes (meloidogyne spp.), potato aphids (macrosiphum euphorbiae), and sweet potato whitefly (bemisia tabaci). to identify genes required in the mi-1-mediated resistance to nematodes and aphids, we used tobacco rattle virus (trv)-based virus-induced gene silencing (vigs) to repress candidate genes and assay for nem ... | 2007 | 17351050 |
| rna-binding proteins that inhibit rna virus infection. | arrays of >5,000 saccharomyces cerevisiae proteins were screened to identify proteins that can preferentially bind a small rna hairpin that contains a clamped adenine motif (cam). a cam is required for the replication of brome mosaic virus (bmv), a plant-infecting rna virus that can replicate in s. cerevisiae. several hits were selected for further characterization in nicotiana benthamiana. pseudouridine synthase 4 (pus4) and the actin patch protein 1 (app1) modestly reduced bmv genomic plus-str ... | 2007 | 17360619 |
| stability of recombinant plant viruses containing genes of unrelated plant viruses. | the stability of hybrid plant viruses that might arise by recombination in transgenic plants was examined using hybrid viruses derived from the viral expression vectors potato virus x (pvx) and tobacco rattle virus (trv). the potato virus y (pvy) nib and hcpro open reading frames (orfs) were introduced into pvx to generate pvx-nib and pvx-hcpro, while the pvy nib orf was introduced into a vector derived from trv rna2 to generate trv-nib. all three viruses were unstable and most of the progeny vi ... | 2007 | 17374781 |
| genetic structure and population variability of tomato yellow leaf curl china virus. | geminiviruses have circular single-stranded dna genomes and are important pathogens in tropical and subtropical regions, but their population diversity and variability are poorly understood. here, we have investigated variations accumulating in tomato yellow leaf curl china virus (tylccnv), a geminivirus in the genus begomovirus of the family geminiviridae. the population variation was analyzed in a naturally infected tomato (solanum lycopersicom) plant and in nicotiana benthamiana and tomato pl ... | 2007 | 17376922 |
| suppressor of rna silencing encoded by the monopartite tomato leaf curl java begomovirus. | we previously isolated the monopartite begomovirus tomato leaf curl java virus (tolcjav) and satellite dnabeta02 from the same naturally infected tomato source in indonesia. tolcjav induced mild leaf curl symptoms in nicotiana benthamiana plants; dnabeta02 encoded the betac1 gene and produced severe leaf curl symptoms when co-inoculated with tolcjav in n. benthamiana. however, dnabeta02mbetac1, which contains a frame shift mutation, did not induce severe symptoms in n. benthamiana when co-inocul ... | 2007 | 17385070 |
| microscopic and transcriptome analyses of early colonization of tomato roots by trichoderma harzianum. | the capacity of the fungus trichoderma harzianum cect 2413 to colonize roots and stimulate plant growth was analyzed. tobacco seedlings (nicotiana benthamiana) transferred to petri dishes inoculated with t. harzianum conidia showed increased plant fresh weight (140%) and foliar area (300%), as well as the proliferation of secondary roots (300%) and true leaves (140%). the interaction between strain cect 2413 and the tomato-root system was also studied during the early stages of root colonization ... | 2007 | 17407057 |
| al1-dependent repression of transcription enhances expression of tomato golden mosaic virus al2 and al3. | studies using nicotiana benthamiana protoplasts have determined that repression of upstream transcription by al1 protein enhances al2 and al3 expression in tomato golden mosaic virus (tgmv). mutations resulting in the inability of tgmv al1 protein to associate with its cognate binding site, result in a decrease in both al2 and al3 expression. reduced expression correlates with an increase in transcription from the al62 start site, and decreased transcription from downstream initiation sites (al1 ... | 2007 | 17407785 |
| rna4-encoded p31 of beet necrotic yellow vein virus is involved in efficient vector transmission, symptom severity and silencing suppression in roots. | rna3 and rna4 of beet necrotic yellow vein virus (bnyvv) are not essential for virus multiplication, but are associated with vector-mediated infection and disease development in sugar beet roots. here, a unique role for rna4 in virus transmission, virulence and rna silencing suppression was demonstrated. mutagenic analysis revealed that the rna4-encoded p31 open reading frame (orf) was involved in efficient vector transmission and slight enhancement of symptom expression in some beta species. no ... | 2007 | 17412994 |
| replication-independent long-distance trafficking by viral rnas in nicotiana benthamiana. | viruses with separately encapsidated genomes could have their genomes introduced into different leaves of a plant, thus necessitating long-distance trafficking of the viral rnas for successful infection. to examine this possibility, individual or combinations of genome segments from the tripartite brome mosaic virus (bmv) were transiently expressed in leaves of nicotiana benthamiana plants using engineered agrobacterium tumefaciens. bmv rna3 was found to traffic from the initial site of expressi ... | 2007 | 17416731 |
| the consensus n-myristoylation motif of a geminivirus ac4 protein is required for membrane binding and pathogenicity. | some geminiviruses encode a small protein, ac4, whose role in pathogenesis has only recently attracted attention. a few studies have shown that this protein is involved in pathogenesis and suppresses rna silencing. here, using nicotiana benthamiana, we show that east african cassava mosaic cameroon virus (eacmcv) ac4 is a pathogenicity determinant and that it suppresses the systemic phase of rna silencing. furthermore, confocal imaging analyses show that it binds preferentially to the plasma mem ... | 2007 | 17427808 |
| a polygalacturonase-inhibiting protein from grapevine reduces the symptoms of the endopolygalacturonase bcpg2 from botrytis cinerea in nicotiana benthamiana leaves without any evidence for in vitro interaction. | six endopolygalacturonases from botrytis cinerea (bcpg1 to bcpg6) as well as mutated forms of bcpg1 and bcpg2 were expressed transiently in leaves of nicotiana benthamiana using agroinfiltration. expression of bcpg1, bcpg2, bcpg4, bcpg5, and mutant bcpg1-d203a caused symptoms, whereas bcpg3, bcpg6, and mutant bcpg2-d192a caused no symptoms. expression of bcpg2 caused the most severe symptoms, including wilting and necrosis. bcpg2 previously has been shown to be essential for b. cinerea virulence ... | 2007 | 17427809 |
| [the c4 proteins of ageratum yellow vein china virus and stachytarpheta leaf curl virus are suppressors of rna silencing]. | rna silencing is a highly conserved mechanism in many eukaryotic organisms that involves sequence-specific rna degradation. one of the important roles of rna silencing is antiviral infection. to counter this defense mechanism, many plant viruses have evolved or acquired functional proteins (suppressors) for suppression of rna silencing. geminiviruses are a family of small circular single-stranded dna (ssdna) viruses that cause severe diseases in major crop plants worldwide. ac2 (c2) and ac4 (c4) ... | 2007 | 17436621 |
| virus-induced gene silencing of 14-3-3 genes abrogates dark repression of nitrate reductase activity in nicotiana benthamiana. | in order to study the effect of repression of 14-3-3 genes on actual activity of the nitrate reductase (nr) in nicotiana benthamiana leaves, nb14-3-3a gene was silenced by virus-induced gene silencing (vigs) method using potato virus x (pvx). expression of nb14-3-3a as well as nb14-3-3b genes was altogether repressed in the leaves of pvx-14-3a-infected plants. furthermore, two-dimensional gel electrophoresis and immunoblot analysis with anti-14-3-3 antiserum suggested that the expressions of nb1 ... | 2007 | 17443349 |
| a tom1 homologue is required for multiplication of tobacco mosaic virus in nicotiana benthamiana. | the attom1 gene of arabidopsis thaliana had been shown to be essential for the efficient multiplication of tobacco mosaic virus (tmv) in a. thaliana. in this study, we cloned an attom1-like gene from nicotiana benthamiana named as nbtom1. sequence alignment showed that nbtom1 is closely related to attom1 homologues of n. tabacum and lycopersicon esculentum with 97.2% and 92.6% nucleotide sequence identities, respectively. silencing of nbtom1 by a modified viral satellite dna-based vector resulte ... | 2007 | 17444600 |
| transgenic nicotiana benthamiana plants resistant to cucumber green mottle mosaic virus based on rna silencing. | rna silencing technology was used to confer resistance to cucumber green mottle mosaic virus (cgmmv). nicotiana benthamiana was transformed with a transgene designed to produce an inverted repeat rna containing cgmmv-coat protein gene (cp) sequences, which were separated by an intron sequence, under the control of the cauliflower mosaic virus 35s promoter. we attempted to confirm the resistance of seven independent transgenic lines; five lines showed resistance to cgmmv infection. the systemic s ... | 2007 | 17453214 |
| abutilon mosaic virus dna b component supports mechanical virus transmission, but does not counteract begomoviral phloem limitation in transgenic plants. | different nicotiana benthamiana lines stably transformed with abutilon mosaic virus (abmv) dimeric dna b were capable of systemically spreading complete bipartite abmv genomes, following agroinoculation of dna a alone. constitutively expressed viral movement protein (bc1) did not induce any persistent disease phenotype, but plants developed transient morphological abnormalities such as radially symmetric leaves after kanamycin withdrawal. systemic abmv infection produced symptoms and virus titer ... | 2007 | 17462695 |
| plant-derived human acetylcholinesterase-r provides protection from lethal organophosphate poisoning and its chronic aftermath. | therapeutically valuable proteins are often rare and/or unstable in their natural context, calling for production solutions in heterologous systems. a relevant example is that of the stress-induced, normally rare, and naturally unstable "read-through" human acetylcholinesterase variant, ache-r. ache-r shares its active site with the synaptic ache-s variant, which is the target of poisonous organophosphate anticholinesterase insecticides such as the parathion metabolite paraoxon. inherent ache-r ... | 2007 | 17475919 |
| expression of human acidic fibroblast growth factor in nicotiana benthamiana with a potato-virus-x-based binary vector. | the afgf (acidic fibroblast growth factor) plays an important role in morphogenesis, angiogenesis and wound healing and is therefore of potential medical interest. a dna fragment encoding hafgf (human afgf) has been cloned into the pvx (potato virus x)-based binary vector (pgr107) and transiently expressed in nicotiana benthamiana (a wild australian tobacco) by agroinfection. approx. 1 week after agroinfection, the recombinant hafgf accumulated in the agroinfected plants reached up to 1% of the ... | 2007 | 17484724 |
| arabidopsis vire2 interacting protein2 is required for agrobacterium t-dna integration in plants. | agrobacterium tumefaciens-mediated genetic transformation is an efficient tool for genetic engineering of plants. vire2 is a single-stranded dna binding agrobacterium protein that is transported into the plant cell and presumably protects the t-dna from degradation. using a yeast two-hybrid system, we identified arabidopsis thaliana vire2-interacting protein2 (vip2) with a not domain that is conserved in both plants and animals. furthermore, we provide evidence supporting vip2 interaction with v ... | 2007 | 17496122 |
| molecular and pathotypic characterization of new xanthomonas oryzae strains from west africa. | dna polymorphism analysis and pathogenicity assays were used to characterize strains of xanthomonas oryzae pv. oryzae and xanthomonas oryzae pv. oryzicola collected from rice leaves in west africa. restriction fragment length polymorphism (rflp), repetitive sequence-based polymerase chain reaction, fluorescent amplified fragment-length polymorphism (faflp) analyses were assessed for molecular characterization, while pathogenicity was tested by leaf clipping and leaf infiltration. dendrograms wer ... | 2007 | 17506331 |
| cytosine methylation is associated with rna silencing in silenced plants but not with systemic and transitive rna silencing through grafting. | rna silencing is often associated with methylation of the target gene. the dna methylation level of transgenes was investigated in post-transcriptionally silenced or non-silenced nicotiana benthamiana carrying either the 5' region (200 or 400 bp) or the entire region of the coat protein gene (cp, including the 3' non-translated region) of sweet potato feathery mottle virus. higher levels of transgene cytosine methylation were observed in both symmetrical (cpg, cpnpg) and non-symmetrical (cphph) ... | 2007 | 17521830 |
| physical association of the nb-lrr resistance protein rx with a ran gtpase-activating protein is required for extreme resistance to potato virus x. | nucleotide binding leucine-rich repeat (nb-lrr) proteins play an important role in plant and mammalian innate immunity. in plants, these resistance proteins recognize specific pathogen-derived effector proteins. recognition subsequently triggers a rapid and efficient defense response often associated with the hypersensitive response and other poorly understood processes that suppress the pathogen. to investigate mechanisms associated with the activation of disease resistance responses, we invest ... | 2007 | 17526750 |
| molecular identification and characterization of the tomato flagellin receptor lefls2, an orthologue of arabidopsis fls2 exhibiting characteristically different perception specificities. | bacterial flagellin is known to stimulate host immune responses in mammals and plants. in arabidopsis thaliana, the receptor kinase fls2 mediates flagellin perception through physical interaction with a highly conserved epitope in the n-terminus of flagellin, represented by the peptide flg22 derived from pseudomonas syringae. the peptide flg22 is highly active as an elicitor in many plant species. in contrast, a shortened version of the same epitope derived from escherichia coli, flg15(e coli), ... | 2007 | 17530419 |
| the nucleoprotein of tomato spotted wilt virus as protein tag for easy purification and enhanced production of recombinant proteins in plants. | upon infection, tomato spotted wilt virus (tswv) forms ribonucleoprotein particles (rnps) that consist of nucleoprotein (n) and viral rna. these aggregates result from the homopolymerization of the n protein, and are highly stable in plant cells. these properties feature the n protein as a potentially useful protein fusion partner. to evaluate this potential, the n protein was fused to the aequorea victoria green fluorescent protein (gfp), either at the amino or carboxy terminus, and expressed i ... | 2007 | 17532227 |
| translational control of recombinant human acetylcholinesterase accumulation in plants. | codon usage differences are known to regulate the levels of gene expression in a species-specific manner, with the primary factors often cited to be mrna processing and accumulation. we have challenged this conclusion by expressing the human acetylcholinesterase coding sequence in transgenic plants in its native gc-rich sequence and compared to a matched sequence with (dicotyledonous) plant-optimized codon usage and a lower gc content. | 2007 | 17537261 |
| changes in photosynthetic metabolism induced by tobamovirus infection in nicotiana benthamiana studied in vivo by thermoluminescence. | * in thylakoids from nicotiana benthamiana infected with the pepper mild mottle virus (pmmov), a decreased amount of the psbp and psbq proteins of photosystem ii and different proteins of the calvin cycle have been previously observed. we used thermoluminescence to study the consequences in vivo. * measurements on unfrozen discs from symptomatic and asymptomatic leaves of plants infected by two tobamovirus pmmov-s and pmmov-i strains were compared with homologous samples in control plants. * the ... | 2007 | 17547672 |
| plant signalling components eds1 and sgt1 enhance disease caused by the necrotrophic pathogen botrytis cinerea. | * botrytis cinerea is a necrotrophic fungus that causes grey mould on a wide range of food plants, especially grapevine, tomato, soft fruits and vegetables. this disease brings about important economic losses in both pre- and postharvest crops. successful protection of host plants against this pathogen is severely hampered by a lack of resistance genes in the hosts and the considerable phenotypic diversity of the fungus. * the aim of this study was to test whether b. cinerea manipulates the immu ... | 2007 | 17547673 |
| genomic regions of tomato leaf curl virus dna satellite required for replication and for satellite-mediated delivery of heterologous dnas. | tomato leaf curl virus (tlcv) satellite dna (sat-dna) is a 682 nt, circular, single-stranded molecule that lacks an open reading frame (orf) or an apparent promoter. it contains binding motifs for the tlcv replication-associated protein, but these are dispensable for replication. to identify the regions of the sat-dna critical for replication, the entire sequence was scanned by deletion/replacement mutagenesis. transient assays using nicotiana benthamiana revealed that sequences within nt 296-35 ... | 2007 | 17554042 |
| quantitative analysis of efficient endogenous gene silencing in nicotiana benthamiana plants using tomato bushy stunt virus vectors that retain the capsid protein gene. | tomato bushy stunt virus (tbsv) coat protein (cp) replacement vectors have been used previously to silence transgenes (e.g., the green fluorescent protein gene) but have not been effective for silencing endogenous plant genes. new tbsv vectors which retained the cp gene were developed by engineering an xhoi restriction site in three positions (3f, ceb, and cea) of the ptbsv-100 infectious clone. magnesium chelatase (chlh) and phytoene desaturase (pds) were chosen as targets for endogenous gene s ... | 2007 | 17555269 |
| downregulation of the nbnaca1 gene encoding a movement-protein-interacting protein reduces cell-to-cell movement of brome mosaic virus in nicotiana benthamiana. | the 3a movement protein (mp) plays a central role in the movement of the rna plant virus, brome mosaic virus (bmv). to identify host factor genes involved in viral movement, a cdna library of nicotiana benthamiana, a systemic host for bmv, was screened with far-western blotting using a recombinant bmv mp as probe. one positive clone encoded a protein with sequence similarity to the alpha chain of nascent-polypeptide-associated complex from various organisms, which is proposed to contribute to th ... | 2007 | 17555275 |
| identification and characterization of a new virus in the genus potyvirus from wild populations of angelica lucida l. and a. genuflexa nutt., family apiaceae. | a novel potyvirus was discovered in angelica lucida l. (wild celery) and a. genuflexa nutt. (kneeling angelica) (family apiaceae) in the matanuska- susitna valley, alaska. the experimental plant host range of the virus included species in three families: chenopodiaceae (chenopodium amaranticolor coste et reyn and chenopodium quinoa willd.), solanaceae (nicotiana benthamiana domin, and n. clevlandii gray.), and apiaceae (anethum graveolens l., apium graveolens l. var. dulce (miller)), daucus caro ... | 2007 | 17558540 |
| a pseudomonas syringae pv. tomato dc3000 mutant lacking the type iii effector hopq1-1 is able to cause disease in the model plant nicotiana benthamiana. | the model pathogen pseudomonas syringae pv. tomato dc3000 causes bacterial speck in tomato and arabidopsis, but nicotiana benthamiana, an important model plant, is considered to be a non-host. strain dc3000 injects approximately 28 effector proteins into plant cells via the type iii secretion system (t3ss). these proteins were individually delivered into n. benthamiana leaf cells via t3ss-proficient pseudomonas fluorescens, and eight, including hopq1-1, showed some capacity to cause cell death i ... | 2007 | 17559511 |
| arabidopsis cytochrome p450 monooxygenase 71a13 catalyzes the conversion of indole-3-acetaldoxime in camalexin synthesis. | camalexin (3-thiazol-2-yl-indole) is an indole alkaloid phytoalexin produced by arabidopsis thaliana that is thought to be important for resistance to necrotrophic fungal pathogens, such as alternaria brassicicola and botrytis cinerea. it is produced from trp, which is converted to indole acetaldoxime (iaox) by the action of cytochrome p450 monooxygenases cyp79b2 and cyp79b3. the remaining biosynthetic steps are unknown except for the last step, which is conversion of dihydrocamalexic acid to ca ... | 2007 | 17573535 |
| expression of a metacaspase gene of nicotiana benthamiana after inoculation with colletotrichum destructivum or pseudomonas syringae pv. tomato, and the effect of silencing the gene on the host response. | metacaspases are cysteine proteinases that have homology to caspases, which play a central role in signaling and executing programmed cell death in animals. a type ii metacaspase cdna, nbmca1, was amplified from nicotiana benthamiana infected with colletotrichum destructivum. it showed a peak in expression at 72 h post-inoculation corresponding with the switch to necrotrophy by c. destructivum. inoculation of n. benthamiana with an incompatible bacterium, pseudomonas syringae pv. tomato, which s ... | 2007 | 17576564 |
| the syntaxin syp132 contributes to plant resistance against bacteria and secretion of pathogenesis-related protein 1. | in contrast to many mammalian pathogens, potential bacterial pathogens of plants remain outside the host cell. the plant must, therefore, promote an active resistance mechanism to combat the extracellular infection. how this resistance against bacteria is manifested and whether similar processes mediate basal, gene-for-gene, and salicylate-associated defense, however, are poorly understood. here, we identify a specific plasma membrane syntaxin, nbsyp132, as a component contributing to gene-for-g ... | 2007 | 17592123 |
| characterization of virus-induced gene silencing in tobacco plants infected with apple latent spherical virus. | apple latent spherical virus (alsv) expressing green fluorescent protein (gfp-alsv) was used for analysis of virus-induced gene silencing (vigs) in tobacco plants expressing gfp (gfp-tobacco). in gfp-tobacco inoculated with gfp-alsv, small dark spots appeared on inoculated leaves at 5 days post-inoculation (dpi), then expanded, and finally covered the whole area of the leaves after 12 dpi. most of the fluorescence of upper leaves above the 12th true leaf disappeared at 21 dpi. thus, gfp-alsv inf ... | 2007 | 17598069 |
| psite vectors for stable integration or transient expression of autofluorescent protein fusions in plants: probing nicotiana benthamiana-virus interactions. | plant functional proteomics research is increasingly dependent upon vectors that facilitate high-throughput gene cloning and expression of fusions to autofluorescent proteins. here, we describe the psite family of plasmids, a new set of agrobacterium binary vectors, suitable for the stable integration or transient expression of various autofluorescent protein fusions in plant cells. the psite vectors permit single-step gateway-mediated recombination cloning for construction of binary vectors tha ... | 2007 | 17601162 |
| bacterial cyclic beta-(1,2)-glucan acts in systemic suppression of plant immune responses. | although cyclic glucans have been shown to be important for a number of symbiotic and pathogenic bacterium-plant interactions, their precise roles are unclear. here, we examined the role of cyclic beta-(1,2)-glucan in the virulence of the black rot pathogen xanthomonas campestris pv campestris (xcc). disruption of the xcc nodule development b (ndvb) gene, which encodes a glycosyltransferase required for cyclic glucan synthesis, generated a mutant that failed to synthesize extracellular cyclic be ... | 2007 | 17601826 |
| tobacco mosaic virus defective rnas expressing c-terminal methyltransferase domain sequences are severely impaired in long-distance movement in nicotiana benthamiana. | tobamovirus replicase proteins, which function in replication and gene expression, are also implicated in viral cell-to-cell and long-distance movement. the role(s) of tobacco mosaic virus (tmv) 126-/183-kda replicase protein in the complex movement process are not understood due to lack of systems that can separate the multiple steps involved. we previously developed a bipartite tmv-defective rna (drna) system to dissect the role of the n-terminal methyltransferase (mt) domain in accumulation a ... | 2007 | 17602721 |
| potyvirus-induced gene silencing: the dynamic process of systemic silencing and silencing suppression. | potato virus a (pva; genus potyvirus) was used for virus-induced gene silencing in a model system that included transgenic nicotiana benthamiana (line 16c) expressing the gfp transgene for green fluorescent protein (gfp) and chimeric pva (pva-gfp) carrying gfp in the p1-encoding region. infection of the 16c plants with pva-gfp in five experiments resulted in a reproducible pattern of systemic gfp transgene silencing, despite the presence of the strong silencing-suppressor protein, hc-pro, produc ... | 2007 | 17622640 |
| the arabidopsis bap1 and bap2 genes are general inhibitors of programmed cell death. | here we identify the bap1 and bap2 genes of arabidopsis (arabidopsis thaliana) as general inhibitors of programmed cell death (pcd) across the kingdoms. these two homologous genes encode small proteins containing a calcium-dependent phospholipid-binding c2 domain. bap1 and its functional partner bon1 have been shown to negatively regulate defense responses and a disease resistance gene snc1. genetic studies here reveal an overlapping function of the bap1 and bap2 genes in cell death control. the ... | 2007 | 17631528 |
| modification of small rnas associated with suppression of rna silencing by tobamovirus replicase protein. | plant viruses act as triggers and targets of rna silencing and have evolved proteins to suppress this plant defense response during infection. although tobacco mosaic tobamovirus (tmv) triggers the production of virus-specific small interfering rnas (sirnas), this does not lead to efficient silencing of tmv nor is a tmv-green fluorescent protein (gfp) hybrid able to induce silencing of a gfp-transgene in nicotiana benthamiana, indicating that a tmv silencing suppressor is active and acts downstr ... | 2007 | 17634237 |
| geminivirus-induced gene silencing of the tobacco retinoblastoma-related gene results in cell death and altered development. | the retinoblastoma-related protein (rbr) is required for cell cycle control and differentiation and is expressed throughout the life of plants and animals. in this study, the tomato golden mosaic virus (tgmv) geminivirus vector was used to silence nbrbr1 in nicotiana benthamiana by microprojectile bombardment into fully developed leaves. similar to previous results using agroinoculation of a tobacco rattle virus silencing vector [park et al. (plant j 42:153, 2005)], developmental defects caused ... | 2007 | 17634748 |
| controlled synthesis of the dsf cell-cell signal is required for biofilm formation and virulence in xanthomonas campestris. | virulence of the black rot pathogen xanthomonas campestris pv. campestris (xcc) is regulated by cell-cell signalling involving the diffusible signal factor dsf. synthesis and perception of dsf require products of genes within the rpf cluster (for regulation of pathogenicity factors). rpff directs dsf synthesis whereas rpfc and rpfg are involved in dsf perception. here we have examined the role of the rpf/dsf system in biofilm formation in minimal medium using confocal laser-scanning microscopy o ... | 2007 | 17635553 |
| genetic and molecular requirements for function of the pto/prf effector recognition complex in tomato and nicotiana benthamiana. | the pto gene of tomato (solanum lycopersicum) confers specific recognition of the unrelated bacterial effector proteins avrpto and avrptob. pto resides in a constitutive molecular complex with the nucleotide binding site-leucine rich repeats protein prf. prf is absolutely required for specific recognition of both effectors. here, using stable transgenic lines, we show that expression of pto from its genomic promoter in susceptible tomatoes was sufficient to complement recognition of pseudomonas ... | 2007 | 17635766 |
| enzymatic properties and subcellular localization of arabidopsis beta-n-acetylhexosaminidases. | plant glycoproteins contain substantial amounts of paucimannosidic n-glycans lacking terminal glcnac residues at their nonreducing ends. it has been proposed that this is due to the action of beta-hexosaminidases during late stages of n-glycan processing or in the course of n-glycan turnover. we have now cloned the three putative beta-hexosaminidase sequences present in the arabidopsis (arabidopsis thaliana) genome. when heterologously expressed as soluble forms in spodoptera frugiperda cells, t ... | 2007 | 17644627 |
| a rangap protein physically interacts with the nb-lrr protein rx, and is required for rx-mediated viral resistance. | race-specific disease resistance in plants is mediated by the products of host disease resistance (r) genes. plant genomes possess hundreds of r gene homologs encoding nucleotide-binding and leucine-rich repeat (nb-lrr) proteins. nb-lrr proteins induce a disease resistance response following recognition of pathogen-encoded avirulence (avr) proteins. however, little is known about the general mechanisms by which nb-lrr proteins recognize avr proteins or how they subsequently induce defense respon ... | 2007 | 17655649 |
| high-frequency reversion of geminivirus replication protein mutants during infection. | the geminivirus replication protein al1 interacts with retinoblastoma-related protein (rbr), a key regulator of the plant division cell cycle, to induce conditions permissive for viral dna replication. previous studies of tomato golden mosaic virus (tgmv) al1 showed that amino acid l148 in the conserved helix 4 motif is critical for rbr binding. in this work, we examined the effect of an l148v mutation on tgmv replication in tobacco cells and during infection of nicotiana benthamiana plants. the ... | 2007 | 17670823 |
| expression of the arabidopsis xrn4p 5'-3' exoribonuclease facilitates degradation of tombusvirus rna and promotes rapid emergence of viral variants in plants. | rapid rna virus evolution is a major problem due to the devastating diseases caused by human, animal and plant-pathogenic rna viruses. a previous genome-wide screen for host factors affecting recombination in tomato bushy stunt tombusvirus (tbsv), a small monopartite plant virus, identified xrn1p 5'-3' exoribonuclease of yeast, a model host, whose absence led to increased appearance of recombinants [serviene, e., shapka, n., cheng, c.p., panavas, t., phuangrat, b., baker, j., nagy, p.d., (2005). ... | 2007 | 17688902 |
| effectiveness and stability of heterologous proteins expressed in plants by turnip mosaic virus vector at five different insertion sites. | the n-terminal (nt) regions of particular protein-coding sequences are generally used for in-frame insertion of heterologous open reading frames (orfs) in potyviral vectors for protein expression in plants. an infectious cdna clone of turnip mosaic virus (tumv) isolate yc5 was engineered at the generally used nt regions of hc-pro and cp, and other possibly permissive sites to investigate their effectiveness to express the gfp (jellyfish green fluorescent protein) and der p 5 (allergen from the d ... | 2007 | 17689817 |
| assessing the expression of chicken anemia virus proteins in plants. | chicken anemia virus (cav) is an important pathogen of chicken worldwide, causing severe anemia and immunodeficiency. its small single-stranded dna genome (2.3kb) encodes three proteins: vp1, the only structural protein, vp2, a protein phosphatase, and vp3, also known as apoptin, which induces apoptosis. in this study, cav proteins were expressed in plants as an alternative for recombinant protein production in animal cells. additionally, the effect of vp3 expression was tested to evaluate possi ... | 2007 | 17698236 |
| mature monomeric forms of hop stunt viroid resist rna silencing in transgenic plants. | viroids, small non-coding pathogenic rnas, are able to induce rna silencing, a phenomenon that has been associated with the pathogenesis and evolution of these small rnas. it has been recently suggested that viroids may resist this plant defense mechanism. however, the simultaneous degradation of non-replicating full-length viroid rna, and the resistance of mature forms of viroids to rna silencing, have not been experimentally demonstrated. transgenic nicotiana benthamiana plants expressing a di ... | 2007 | 17711417 |
| pseudomonas syringae type iii effector avrptob is phosphorylated in plant cells on serine 258, promoting its virulence activity. | the pseudomonas syringae pv. tomato protein avrptob is translocated into plant cells via the bacterial type iii secretion system. in resistant tomato leaves, avrptob acts as an avirulence protein by interacting with the host pto kinase and eliciting the host immune response. pto-mediated immunity requires prf, a pto-interacting protein with a putative nucleotide-binding site and a region of leucine-rich repeats. in susceptible tomato plants, which lack either pto or prf, avrptob acts as a virule ... | 2007 | 17711844 |
| expression of animal ced-9 anti-apoptotic gene in tobacco modifies plasma membrane ion fluxes in response to salinity and oxidative stress. | apoptosis, one form of programmed cell death (pcd), plays an important role in mediating plant adaptive responses to the environment. recent studies suggest that expression of animal anti-apoptotic genes in transgenic plants may significantly improve a plant's ability to tolerate a variety of biotic and abiotic stresses. the underlying cellular mechanisms of this process remain unexplored. in this study, we investigated specific ion flux "signatures" in nicotiana benthamiana plants transiently e ... | 2007 | 17712568 |
| a novel nuclear protein interacts with the symbiotic dmi3 calcium- and calmodulin-dependent protein kinase of medicago truncatula. | many higher plants establish symbiotic relationships with arbuscular mycorrhizal (am) fungi that improve their ability to acquire nutrients from the soil. in addition to establishing am symbiosis, legumes also enter into a nitrogen-fixing symbiosis with bacteria known as rhizobia that results in the formation of root nodules. several genes involved in the perception and transduction of bacterial symbiotic signals named "nod factors" have been cloned recently in model legumes through forward gene ... | 2007 | 17722695 |
| comparative expression profiling of nicotiana benthamiana leaves systemically infected with three fruit tree viruses. | plant viruses cause a wide array of disease symptoms and cytopathic effects. although some of these changes are virus specific, many appear to be common even among diverse viruses. currently, little is known about the underlying molecular determinants. to identify gene expression changes that are concomitant with virus symptoms, we performed comparative expression profiling experiments on nicotiana benthamiana leaves infected with one of three different fruit tree viruses that produce distinct s ... | 2007 | 17722703 |
| recovery of nicotiana benthamiana plants from a necrotic response induced by a nepovirus is associated with rna silencing but not with reduced virus titer. | recovery of plants from virus-induced symptoms is often described as a consequence of rna silencing, an antiviral defense mechanism. for example, recovery of nicotiana clevelandii from a nepovirus (tomato black ring virus) is associated with a decreased viral rna concentration and sequence-specific resistance to further virus infection. in this study, we have characterized the interaction of another nepovirus, tomato ringspot virus (torsv), with host defense responses during symptom induction an ... | 2007 | 17728227 |
| infection, propagation, distribution and stability of plant virus in hairy root cultures. | nicotiana benthamiana hairy root cultures were infected with tobacco mosaic virus (tmv) and used for in vitro plant virus propagation. the roots were infected with tmv by addition of virus to the medium at the same time as root inoculation. viral accumulation in the biomass was 7-11-fold greater when the initial infection was carried out in b5 medium rather than sodium phosphate buffer; virus accumulation also increased with increasing viral inoculum concentration. the amount of tmv accumulated ... | 2007 | 17767969 |
| ap2-erf transcription factors mediate nod factor dependent mt enod11 activation in root hairs via a novel cis-regulatory motif. | rhizobium nod factors (nfs) are specific lipochitooligosaccharides that activate host legume signaling pathways essential for initiating the nitrogen-fixing symbiotic association. this study describes the characterization of cis-regulatory elements and trans-interacting factors that regulate nf-dependent and epidermis-specific gene transcription in medicago truncatula. detailed analysis of the mt enod11 promoter using deletion, mutation, and gain-of-function constructs has led to the identificat ... | 2007 | 17827349 |
| a chimeric plum pox virus shows reduced spread and cannot compete with its parental wild-type viruses in a mixed infection. | the effect of a recombination event in the genomic 3' end on the biological properties and competitiveness of plum pox virus (ppv) was investigated. therefore, a fragment spanning the coat protein (cp) coding region and a part of the 3' non-translated region of a non-aphid-transmissible strain of ppv (ppv-nat) was replaced by the corresponding region of a ppv sour cherry isolate (ppv-soc). the resulting chimera (ppv-nat/soc) caused severe symptoms in nicotiana benthamiana, resembling those of pp ... | 2007 | 17872539 |
| a cucumber mosaic virus mutant lacking the 2b counter-defence protein gene provides protection against wild-type strains. | several plant virus mutants, in which genes encoding silencing suppressor proteins have been deleted, are known to induce systemic or localized rna silencing against themselves and other rna molecules containing homologous sequences. thus, it is thought that many cases of cross-protection, in which infection with a mild or asymptomatic virus mutant protects plants against challenge infection with closely related virulent viruses, can be explained by rna silencing. we found that a cucumber mosaic ... | 2007 | 17872541 |
| the chimeric cyclic nucleotide-gated ion channel atcngc11/12 constitutively induces programmed cell death in a ca2+ dependent manner. | the hypersensitive response (hr) involves programmed cell death (pcd) in response to pathogen infection. to investigate the pathogen resistance signaling pathway, we previously identified the arabidopsis mutant cpr22, which displays constitutive activation of multiple defense responses including hr like cell death. the cpr22 mutation has been identified as a 3 kb deletion that fuses two cyclic nucleotide-gated ion channel (cngc)-encoding genes, atcngc11 and atcngc12, to generate a novel chimeric ... | 2007 | 17885810 |
| virp1 is a host protein with a major role in potato spindle tuber viroid infection in nicotiana plants. | viroids are small, circular, single-stranded rna molecules that, while not coding for any protein, cause several plant diseases. viroids rely for their infectious cycle on host proteins, most of which are likely to be involved in endogenous rna-mediated phenomena. therefore, characterization of host factors interacting with the viroid may contribute to the elucidation of rna-related pathways of the hosts. potato spindle tuber viroid (pstvd) infects several members of the solanaceae family. in an ... | 2007 | 17898061 |
| resistance to grapevine leafroll associated virus-2 is conferred by post-transcriptional gene silencing in transgenic nicotiana benthamiana. | grapevine leafroll-associated virus-2 (glrav-2) is an important component of the leafroll disease complex in grapevine. we have previously sequenced the glrav-2 genome and identified the coat protein (cp) gene. the objective of this study is to test the concept of pathogen-derived resistance against a closterovirus associated with grapevine leafroll disease. because glrav-2 is capable of infecting nicotiana benthamiana, we decided to test the concept on this herbaceous host. thirty-seven t(0) tr ... | 2008 | 17912600 |
| antagonistic control of powdery mildew host cell entry by barley calcium-dependent protein kinases (cdpks). | calcium-dependent protein kinases (cdpks) are known to play pivotal roles in intracellular signaling during abiotic and biotic stress responses. to unravel potential functions of cdpks in the course of barley (hordeum vulgare)-powdery mildew (blumeria graminis) interactions, we systematically analyzed the hvcdpk gene family. we found that, according to the existence of respective expressed sequence tags, at least nine paralogs are expressed in the barley leaf epidermis, the sole target tissue of ... | 2007 | 17918623 |
| new type iii effectors from xanthomonas campestris pv. vesicatoria trigger plant reactions dependent on a conserved n-myristoylation motif. | pathogenicity of the gram-negative plant pathogen xanthomonas campestris pv. vesicatoria depends on a type iii secretion system, which translocates bacterial effector proteins into the plant cell. in this study, we identified two novel type iii effectors, xope1 and xope2 (xanthomonas outer proteins), using the avrbs3 effector domain as reporter. xope1 and xope2 belong to the hopx family and possess a conserved putative n-myristoylation motif that is also present in the effector xopj from x. camp ... | 2007 | 17918627 |
| oligonucleotide microarray-based detection and genotyping of plum pox virus. | plum pox virus (ppv) is the most damaging viral pathogen of stone fruits. the detection and identification of its strains are therefore of critical importance to plant quarantine and certification programs. existing methods to screen strains of ppv suffer from significant limitations such as the simultaneous detection and genotyping of several strains of ppv in samples infected with different isolates of the virus. a genomic strategy for ppv screening based on the viral nucleotide sequence was d ... | 2008 | 17920703 |
| the pclean dual binary vector system for agrobacterium-mediated plant transformation. | the development of novel transformation vectors is essential to the improvement of plant transformation technologies. here, we report the construction and testing of a new multifunctional dual binary vector system, pclean, for agrobacterium-mediated plant transformation. the pclean vectors are based on the widely used pgreen/psoup system and the pclean-g/pclean-s plasmids are fully compatible with the existing pgreen/psoup vectors. a single agrobacterium can harbor (1) pclean-g and psoup, (2) pg ... | 2007 | 17932303 |
| a ligation-independent cloning tobacco rattle virus vector for high-throughput virus-induced gene silencing identifies roles for nbmads4-1 and -2 in floral development. | virus-induced gene silencing (vigs) is a widely used, powerful technique for reverse genetics. vigs vectors derived from the tobacco rattle virus (trv) are among the most popular for vigs. we have developed a trv rna2 vector that allows the insertion of gene silencing fragments by ligation-independent cloning (lic). this new vector has several advantages over previous vectors, particularly for applications involving the analysis of large numbers of sequences, since trv-lic vectors containing the ... | 2007 | 17932306 |
| solanum lycopersicon mill. and nicotiana benthamiana l. under high light show distinct responses to anti-oxidative stress. | two experimentally important species, solanum lycopersicon mill. and nicotiana benthamiana l., were propagated in vitro under low light (50 micromol m(-2) s(-1)) and transferred to hl (200 micromol m(-2) s(-1)) under a protocol previously developed for grapevine and chestnut. compared with photooxidative stress parameters already tested in those species, imaging of hydrogen peroxide and superoxide revealed an accumulation on d2-3 and d6 in s. lycopersicon and d1-2 and d5-7 in n. benthamiana. sod ... | 2008 | 17945381 |
| size reversion of a truncated dnabeta associated with tobacco curly shoot virus. | our previous results demonstrated that dnabeta associated with tobacco curly shoot virus (tbcsv) is not necessary for infection but intensifies symptoms in some hosts. to better understand the function of dnabeta in virus infection, a betac1 deleted infectious clone of the tbcsv dnabeta was constructed. agroinoculation showed that the truncated dnabeta (dnadeltac1beta) was trans-replicated by tbcsv in tobacco and petunia hybrida plants. however, pcr and southern blot analysis demonstrated that t ... | 2008 | 17950948 |
| alternative splicing and mrna levels of the disease resistance gene rps4 are induced during defense responses. | the arabidopsis (arabidopsis thaliana) disease resistance protein resistance to pseudomonas syringae4 (rps4) activates defenses in response to bacterial pathogens expressing avrrps4 in a gene-for-gene specific manner. the rps4 gene produces multiple transcripts via alternative splicing of two regular introns flanking exon 3 and a cryptic intron within exon 3. we showed previously that rps4-mediated resistance requires the combined presence of transcripts encoding both full-length and truncated o ... | 2007 | 17951452 |
| point mutations in helper component protease of clover yellow vein virus are associated with the attenuation of rna-silencing suppression activity and symptom expression in broad bean. | helper component protease (hc-pro) is a potyvirus-encoded multifunctional protein and a major determinant of symptom expression in a susceptible plant. here, we show the involvement of clover yellow vein virus (clyvv) hc-pro in necrotic symptom expression in broad bean (vicia faba cv. wase). in this host, lethal necrosis was induced by clyvv no. 30, from which a spontaneous, mosaic-inducing mutant (mm) was obtained. mapping with chimeric viruses between clyvv no. 30 and mm attributed the symptom ... | 2008 | 17955160 |
| induction of a small heat shock protein and its functional roles in nicotiana plants in the defense response against ralstonia solanacearum. | in tobacco (nicotiana tabacum), ralstonia solanacearum oe1-1 (rsoe1-1) is pathogenic, whereas r. solanacearum 8107 (rs8107) is nonpathogenic and induces the hypersensitive response (hr). to elucidate the molecular mechanisms of plant-r. solanacearum interactions, we used differential display to isolate a cdna fragment, a6, regulated in tobacco by inoculation with rsoe1-1. the deduced amino acid sequence predicted from full-length a6-cdna showed similarity to small heat shock proteins from arabid ... | 2007 | 17965181 |
| transient expression of hpv16 e7 peptide (aa 44-60) and hpv16 l2 peptide (aa 108-120) on chimeric potyvirus-like particles using potato virus x-based vector. | the optimized expression of recombinant potato virus a coat protein (acp) carrying two different epitopes from human papillomavirus type 16 (hpv16) was developed. epitope derived from minor capsid protein l2 was expressed as n-terminal fusion with acp while an epitope derived from e7 oncoprotein was fused to its c-terminus. the construct was cloned into potato x potexvirus (pvx) based vector and transiently expressed in plants using agrobacterium tumefaciens mediated inoculation. to increase the ... | 2008 | 17980618 |
| high-level transient production of a heterologous protein in plants by optimizing induction of a chemically inducible viral amplicon expression system. | we have demonstrated that the method of chemical induction using a chemically inducible viral amplicon expression system can be optimized to increase expression of a heterologous protein in plants. a cucumber mosaic virus inducible viral amplicon (cmviva) expression system was used to transiently produce a recombinant human blood protein, alpha-1-antitrypsin (aat), by co-infiltrating intact and detached nicotiana benthamiana leaves with two agrobacterium tumefaciens strains, one containing the c ... | 2007 | 17994759 |
| a systematic study to determine the extent of gene silencing in nicotiana benthamiana and other solanaceae species when heterologous gene sequences are used for virus-induced gene silencing. | virus-induced gene silencing (vigs) is a rapid and robust method for determining and studying the function of plant genes or expressed sequence tags (ests). however, only a few plant species are amenable to vigs. there is a need for a systematic study to identify vigs-efficient plant species and to determine the extent of homology required between the heterologous genes and their endogenous orthologs for silencing. two approaches were used. first, the extent of phytoene desaturase (pds) gene sil ... | 2007 | 17997764 |
| the arabidopsis vacuolar malate channel is a member of the almt family. | in plants, malate is a central metabolite and fulfills a large number of functions. vacuolar malate may reach very high concentrations and fluctuate rapidly, whereas cytosolic malate is kept at a constant level allowing optimal metabolism. recently, a vacuolar malate transporter (arabidopsis thaliana tonoplast dicarboxylate transporter, attdt) was identified that did not correspond to the well-characterized vacuolar malate channel. we therefore hypothesized that a member of the aluminum-activate ... | 2007 | 18005230 |
| genomic resources for myzus persicae: est sequencing, snp identification, and microarray design. | the green peach aphid, myzus persicae (sulzer), is a world-wide insect pest capable of infesting more than 40 plant families, including many crop species. however, despite the significant damage inflicted by m. persicae in agricultural systems through direct feeding damage and by its ability to transmit plant viruses, limited genomic information is available for this species. | 2007 | 18021414 |
| one-step cloning approach for construction of agroinfectious begomovirus clones. | most begomoviruses have a bipartite genome containing two circular ssdna segments (dna-a and dna-b). routine infectious clone construction relies upon cloning of the whole genome, which is then subcloned as a tandem one-and-half or two genome- (containing two replication origins) cassette into a vector prior to agro-inoculation. the construction of cassettes containing two replication origins is, however, a time-consuming process. here an improved method for rapid construction of agroinfectious ... | 2008 | 18022703 |
| intracellular targeting of a hordeiviral membrane-spanning movement protein: sequence requirements and involvement of an unconventional mechanism. | the membrane-spanning protein tgbp3 is one of the three movement proteins (mps) of poa semilatent virus. tgbp3 is thought to direct other viral mps and genomic rna to peripheral bodies located in close proximity to plasmodesmata. we used the ectopic expression of green fluorescent protein-fused tgbp3 in epidermal cells of nicotiana benthamiana leaves to study the tgbp3 intracellular trafficking pathway. treatment with inhibitors was used to reveal that the targeting of tgbp3 to plasmodesmata doe ... | 2008 | 18032484 |
| replication-coupled packaging mechanism in positive-strand rna viruses: synchronized coexpression of functional multigenome rna components of an animal and a plant virus in nicotiana benthamiana cells by agroinfiltration. | flock house virus (fhv), a bipartite rna virus of insects and a member of the nodaviridae family, shares viral replication features with the tripartite brome mosaic virus (bmv), an rna virus that infects plants and is a member of the bromoviridae family. in bmv and fhv, genome packaging is coupled to replication, a widely conserved mechanism among positive-strand rna viruses of diverse origin. to unravel the events that modulate the mechanism of replication-coupled packaging, in this study, we h ... | 2008 | 18032497 |
| adaptation of the "in-gel release method" to n-glycome analysis of low-milligram amounts of material. | protein n-glycosylation is a post-translational modification which plays numerous crucial physiological roles. the n-glycan pattern varies depending on the species organs, tissues and even cell types and their respective physiological states. obtaining enough starting material from a particular cell type or tissue for n-glycan purification by conventional methods can, in certain cases, be very difficult. previously, a sensitive technique, the "in-gel release method" that allows the determination ... | 2007 | 18041037 |
| calcium efflux as a component of the hypersensitive response of nicotiana benthamiana to pseudomonas syringae. | using a model plant nicotiana benthamiana, we have demonstrated that initial calcium uptake in response to the hr (hypersensitive response)-causing pathogen pseudomonas syringae pv syringae 61 is followed by net calcium efflux initiated at about 12 h after the bacterial challenge and sustained for at least 48 h. our data suggest that calcium not only acts as an important second messenger in the activation of resistance responses but may also be a downstream mediator of later cell death accelerat ... | 2008 | 18048411 |
| interaction between sgt1 and cytosolic/nuclear hsc70 chaperones regulates arabidopsis immune responses. | the conserved eukaryotic protein sgt1 (for suppressor of g2 allele of skp1) has characteristics of an hsp90 (for heat shock protein 90 kd) cochaperone and in plants regulates hormone responses and resistance gene-triggered immunity. we affinity-purified sgt1-interacting proteins from arabidopsis thaliana leaf extracts and identified by mass spectrometry cytosolic heat shock cognate 70 (hsc70) chaperones as the major stable sgt1 interactors. arabidopsis sgt1a and sgt1b proteins associate with hsc ... | 2007 | 18065690 |
| biosynthesis of circular proteins in plants. | plant cyclotides are a large family of naturally occurring circular proteins that are produced from linear precursors containing one, two or three cyclotide domains. the mechanism of excision of the cyclotide domains and ligation of the free n- and c-termini to produce the circular peptides has not been elucidated. here, we investigate production of the prototypic cyclotide kalata b1 from the precursor oak1 from the african plant oldenlandia affinis. immunoprecipitation experiments and maldi-tof ... | 2008 | 18086282 |
| partial demethylation of oligogalacturonides by pectin methyl esterase 1 is required for eliciting defence responses in wild strawberry (fragaria vesca). | in addition to the role of the cell wall as a physical barrier against pathogens, some of its constituents, such as pectin-derived oligogalacturonides (oga), are essential components for elicitation of defence responses. to investigate how modifications of pectin alter defence responses, we expressed the fruit-specific fragaria x ananassa pectin methyl esterase fape1 in the wild strawberry fragaria vesca. pectin from transgenic ripe fruits differed from the wild-type with regard to the degree an ... | 2008 | 18088306 |
| pathogenicity of a naturally occurring recombinant dna satellite associated with tomato yellow leaf curl china virus. | recombinant dna beta molecules (recdna-abeta) comprising parts of dna a and dna beta associated with tomato yellow leaf curl china virus (tylccnv) have been identified in naturally infected tobacco plants. several examples of the recombinant dna have been cloned and characterized by sequence analysis. all are approximately half the size of tylccnv genomic dna, and all contain the betac1 gene and the a-rich region from tylccnv dna beta as well as intergenic region sequences and the 5' terminus of ... | 2008 | 18089755 |
| regulation of rice nadph oxidase by binding of rac gtpase to its n-terminal extension. | reactive oxygen species (ros) produced by nadph oxidase play critical roles in various cellular activities, including plant innate immunity response. in contrast with the large multiprotein nadph oxidase complex of phagocytes, in plants, only the homologs of the catalytic subunit gp91phox and the cytosolic regulator small gtpase rac are found. plant homologs of the gp91phox subunit are known as rboh (for respiratory burst oxidase homolog). although numerous rboh have been isolated in plants, the ... | 2007 | 18156215 |
| salicylic acid and systemic acquired resistance play a role in attenuating crown gall disease caused by agrobacterium tumefaciens. | we investigated the effects of salicylic acid (sa) and systemic acquired resistance (sar) on crown gall disease caused by agrobacterium tumefaciens. nicotiana benthamiana plants treated with sa showed decreased susceptibility to agrobacterium infection. exogenous application of sa to agrobacterium cultures decreased its growth, virulence, and attachment to plant cells. using agrobacterium whole-genome microarrays, we characterized the direct effects of sa on bacterial gene expression and showed ... | 2008 | 18156296 |
| cis- and trans-acting functions of brome mosaic virus protein 1a in genomic rna1 replication. | rna viruses employ a combination of mechanisms to regulate their gene expression and replication. brome mosaic virus (bmv) is a tripartite positive-strand rna virus used to study the requirements for virus infection. bmv genomic rna1 encodes protein 1a, which contains a methyltransferase (mt) domain and a helicase domain that are required for replication. 1a forms a complex with the 2a rna-dependent rna polymerase for the replication and transcription of all bmv rnas. rna1 expressed with 2a from ... | 2008 | 18160434 |
| characterization of a defective rna derived from rna 3 of the y strain of cucumber mosaic virus. | a defective (d) rna 3 naturally generated from the y strain of cucumber mosaic virus (cmv-y) was characterized using a biologically active cdna clone. sequencing of the clone revealed that the d rna 3, named d rna 3yalpha, was derived from cmv-y rna 3 and contained a 10 nt deletion in the 5' untranslated region and a 162 nt deletion within the 3a open reading frame. co-inoculation of d rna 3yalpha with cmv-y derived from in vitro transcripts facilitated propagation of cmv-y containing d rna 3yal ... | 2008 | 18175038 |
| infectivity of the cloned components of a begomovirus: dna beta complex causing chilli leaf curl disease in india. | the full-length genome of a begomovirus and its cognate dna-beta satellite component associated with chilli leaf curl disease (chlcd), originating from varanasi, india, were cloned. sequence analysis revealed that the viral genome (ef190217) is 2,750 bp and the dna-beta satellite (ef190215) is 1,361 bp in length. agroinoculation with partial tandem repeats of the viral genome along with the satellite induced symptoms typical of chlcd in chilli and nicotiana benthamiana. however, symptom expressi ... | 2008 | 18175042 |
| a genomic map of viroid rna motifs critical for replication and systemic trafficking. | rna replication and systemic trafficking play significant roles in developmental regulation and host-pathogen interactions. viroids are the simplest noncoding eukaryotic rna pathogens and genetic units that are capable of autonomous replication and systemic trafficking and offer excellent models to investigate the role of rna structures in these processes. like other rnas, the predicted secondary structure of a viroid rna contains many loops and bulges flanked by double-stranded helices, the bio ... | 2008 | 18178767 |
| physiological function of ispe, a plastid mep pathway gene for isoprenoid biosynthesis, in organelle biogenesis and cell morphogenesis in nicotiana benthamiana. | isoprenoid biosynthesis in plants occurs by two independent pathways: the cytosolic mevalonate (mva) pathway and the plastidic methylerythritol phosphate (mep) pathway. in this study, we investigated the cellular effects of depletion of ispe, a protein involved in the mep pathway, using virus-induced gene silencing (vigs). the ispe gene is preferentially expressed in young tissues, and induced by light and methyl jasmonate. the gfp fusion protein of ispe was targeted to chloroplasts. reduction o ... | 2008 | 18180879 |
| phenotypes and functional effects caused by various viral rna silencing suppressors in transgenic nicotiana benthamiana and n. tabacum. | rna silencing suppressor genes derived from six virus genera were transformed into nicotiana benthamiana and n. tabacum plants. these suppressors were p1 of rice yellow mottle virus (rymv), p1 of cocksfoot mottle virus, p19 of tomato bushy stunt virus, p25 of potato virus x, hcpro of potato virus y (strain n), 2b of cucumber mosaic virus (strain kin), and ac2 of african cassava mosaic virus (acmv). hcpro caused the most severe phenotypes in both nicotiana spp. ac2 also produced severe effects in ... | 2008 | 18184062 |
| biological activity of transcripts from cdna of pelargonium line pattern virus. | a set of cdnas of pelargonium line pattern virus (plpv) was assembled under the control of t7 rna polymerase promoter and ligated into the plasmid puc18. transcripts synthesized in vitro from cdna were infectious on chenopodium quinoa according to locally induced lesions and hybridization assay. the biological activity of the viral transcripts was particularly sensitive to the short 3' terminus extensions, whereas inclusion of the 3 extra bases at the 5' terminus did not substantially affect the ... | 2007 | 18197735 |
| recognition of the hyaloperonospora parasitica effector atr13 triggers resistance against oomycete, bacterial, and viral pathogens. | phytopathogenic oomycetes cause some of the most devastating diseases affecting agricultural crops. hyaloperonospora parasitica is a native oomycete pathogen of arabidopsis and is related to other oomycete phytopathogens that include several species of phytophthora, including the causal agent of potato late blight. recently, four oomycete effector genes have been isolated, and several oomycete genomes have been sequenced. we have developed an efficient and genetically amenable system to test put ... | 2008 | 18198274 |
| class viii myosins are required for plasmodesmatal localization of a closterovirus hsp70 homolog. | the hsp70 homolog (hsp70h) of beet yellows virus (byv) functions in virion assembly and cell-to-cell movement and is autonomously targeted to plasmodesmata in association with the actomyosin motility system (a. i. prokhnevsky, v. v. peremyslov, and v. v. dolja, j. virol. 79:14421-14428, 2005). myosins are a diverse category of molecular motors that possess a motor domain and a tail domain involved in cargo binding. plants have two classes of myosins, viii and xi, whose specific functions are poo ... | 2008 | 18199648 |
| salicylic acid production in response to biotic and abiotic stress depends on isochorismate in nicotiana benthamiana. | salicylic acid (sa) is an important signal involved in the activation of defence responses against abiotic and biotic stress. in tobacco, benzoic acid or glucosyl benzoate were proposed to be precursors of sa. this is in sharp contrast with studies in arabidopsis thaliana, where sa derives from isochorismate. we have determined the importance of isochorismate for sa biosynthesis in nicotiana benthamiana using virus-induced gene silencing of the isochorismate synthase (ics) gene. plants with sile ... | 2008 | 18201575 |