Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
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| peanut stripe potyvirus resistance in peanut (arachis hypogaea l.) plants carrying viral coat protein gene sequences. | peanut (arachis hypogaea l.) lines exhibiting high levels of resistance to peanut stripe virus (pstv) were obtained following microprojectile bombardment of embryogenic callus derived from mature seeds. fertile plants of the commercial cultivars gajah and nc7 were regenerated following co-bombardment with the hygromycin resistance gene and one of two forms of the pstv coat protein (cp) gene, an untranslatable, full length sequence (cp2) or a translatable gene encoding a cp with an n-terminal tru ... | 2004 | 15070076 |
| the n-glycosidase activity of the ribosome-inactivating protein me1 targets single-stranded regions of nucleic acids independent of sequence or structural motifs. | me(1), a type i ribosome-inactivating protein (rip), belongs to a family of enzymes long believed to possess rrna n-glycosidase activity directed solely at the universally conserved residue a4324 in the sarcin/ricin loop of large eukaryotic and prokaryotic rrnas. we have investigated the effect of modifying the structure of nonribosomal rna substrates on their interaction with me(1) and other rips. me(1) was shown to depurinate a variety of partially denatured nucleic acids, randomly removing ad ... | 2004 | 15123667 |
| direct role of a viroid rna motif in mediating directional rna trafficking across a specific cellular boundary. | the plasmodesmata and phloem form a symplasmic network that mediates direct cell-cell communication and transport throughout a plant. selected endogenous rnas, viral rnas, and viroids traffic between specific cells or organs via this network. whether an rna itself has structural motifs to potentiate trafficking is not well understood. we have used mutational analysis to identify a motif that the noncoding potato spindle tuber viroid rna evolved to potentiate its efficient trafficking from the bu ... | 2004 | 15194818 |
| biolistic inoculation of plants with viroid nucleic acids. | parameters for biolistic transfer of viroid nucleic acids using a helios gene gun device were assayed. the main achievement of this method is high efficiency of inoculation with linear monomeric viroid cdnas and rnas. this greatly facilitates the study of mutated sequence variants, viroid libraries and mixed populations. the lower limits for efficient inoculation of monomeric cdna fragments with the sequence of potato spindle tuber viroid (pstvd) and native pstvd rna as detected 21 days p.i. are ... | 2004 | 15542139 |
| the 18s rdna sequence of synchytrium endobioticum and its utility in microarrays for the simultaneous detection of fungal and viral pathogens of potato. | resting spores extracted from wart (synchytrium endobioticum)-infected potato tubers were used for dna extraction and amplification of 18s rdna. analysis of the cloned, sequenced fragment revealed high similarity to members of the chytridiomycota. using this information, specific oligonucleotide probes were designed and arrayed onto glass slides for detection of the pathogen. viral sequence information available in the databank was retrieved, or new viral sequences were generated, and used to de ... | 2005 | 15800764 |
| co-inoculation with two non-infectious cdna copies of potato spindle tuber viroid (pstvd) leads to the appearance of novel fully infectious variants. | potato spindle tuber viroid (pstvd) is one of the smallest (about 360 nt) infectious plant agents. it is composed of a single-stranded circular non-coding rna molecule. in the course of previous passage experiments with two intermediate pstvd variants i2 and i4, three non-infectious clones (i2-50, i4-37 and i4 vi-17) were found. when inoculated separately as cdnas on tomato "rutgers" test plants these variants did not induce any visible disease symptoms and did not produce progeny. the presence ... | 2005 | 15827608 |
| mutational analysis does not support the existence of a putative tertiary structural element in the left terminal domain of potato spindle tuber viroid. | comparative sequence analysis suggests that the left terminal domain of potato spindle tuber viroid (pstvd) and other large pospiviroids may assume a branched tertiary structure containing two pseudoknots. to search for evidence of such a structure in vivo, the nucleotide sequences proposed to interact were mutagenized, tomato seedlings were inoculated with mixtures of potentially infectious pstvd rna transcripts and the resulting progeny were screened for compensatory sequence changes. position ... | 2005 | 15914863 |
| correlation between structure and pathogenicity of potato spindle tuber viroid (pstv). | sequence analysis by primer-extension at the level of their cdna showed that the rna genomes of various field isolates of potato spindle tuber viroid (pstv) of different virulence differ from each other only in a few nucleotides in two distinct regions of the rod-shaped molecule. despite insertions and deletions the chain length of 359 nucleotides is strictly conserved in all the isolates studied. thermodynamic calculations revealed that due to the observed sequence differences the region locate ... | 1985 | 15938051 |
| infectivity studies on different potato spindle tuber viroid (pstv) rnas synthesized in vitro with the sp6 transcription system. | we have constructed two sets of clones in which one to six head-to-tail connected dna copies of the potato spindle tuber viroid (pstv) rna genome were inserted into the plasmid psp62- pl downstream of the promoter for sp6 rna polymerase. in vitro transcription of these constructs with the promoter-specific sp6 rna polymerase yielded the corresponding oligomeric single-stranded linear pstv rna molecules of (+) and (-) polarity. except for short vector-derived terminal sequences these in vitro syn ... | 1985 | 15938052 |
| investigating the specificity of real-time pcr assays using synthetic oligonucleotides. | potato spindle tuber viroid (pstvd) causes damaging diseases of solanaceous crops and is a quarantine pathogen in the european union. previously a one-tube real-time rt-pcr assay based on taqman chemistry was developed and shown to be ideally suited to pstvd detection. however, since it was impossible to trace infected plant material for every published pstvd sequence reported, in silico predictions were made about assay specificity based on the positions of nucleotide polymorphisms within the p ... | 2005 | 16051376 |
| transcription of potato spindle tuber viroid by rna polymerase ii starts in the left terminal loop. | viroids are single-stranded, circular rnas of 250 to 400 bases, that replicate autonomously in their host plants but do not code for a protein. viroids of the family pospiviroidae, of which potato spindle tuber viroid (pstvd) is the type strain, are replicated by the host's dna-dependent rna polymerase ii in the nucleus. to analyze the initiation site of transcription from the (+)-stranded circles into (-)-stranded replication intermediates, we used a nuclear extract from a non-infected cell cul ... | 2006 | 16406459 |
| amino acid sequence of the ;pathogenesis-related' leaf protein p14 from viroid-infected tomato reveals a new type of structurally unfamiliar proteins. | we have established the complete sequence of the 130 amino acid residues of the pathogenesis-related (pr) protein p14 accumulating in tomato leaves infected with the viroid of the spindle tuber disease of potato (pstv) and partial sequences of the pr protein 1a which accumulates in tobacco mosaic virus-infected tobacco leaves. both pr proteins are closely related to each other. however, no homology could be found between the sequence of p14 and any of the 3061 published protein sequences compile ... | 1985 | 16453639 |
| linear oligomeric potato spindle tuber viroid (pstv) rnas are accurately processed in vitro to the monomeric circular viroid proper when incubated with a nuclear extract from healthy potato cells. | a nuclear extract for the processing of oligomeric viroid rna in vitro has been prepared from nuclei isolated from healthy potato cells grown in suspension culture. linear rna molecules containing concatameric units of (+) or (-) strands, respectively, of the potato spindle tuber viroid (pstv) were synthesized in vitro with the aid of the sp6 rna polymerase and used as substrates for processing. when oligomeric linear pstv (+)rnas are incubated with the nuclear extract, monomeric linear molecule ... | 1987 | 16453784 |
| hybridization of potato spindle tuber viroid to cellular dna of normal plants. | molecular hybridization experiments of (125)i-labeled potato spindle tuber viroid (pstv) with dna from uninfected or pstv-infected tomato plants showed that infrequent dna sequences complementary to pstv exist in both uninfected and infected cells. dna titration experiments revealed that at least 60% of pstv is represented by sequences in dna of several normal solanaceous host species. phylogenetically diverse plants contain sequences related to less of the pstv. pstv-infected tomato or gynura a ... | 1976 | 16592335 |
| potato spindle tuber and citrus exocortis viroids undergo no major sequence changes during replication in two different hosts. | potato spindle tuber viroid and citrus exocortis viroid, each purified from tomato (lycopersicon esculentum) and from gynura aurantiaca, were iodinated in vitro with (125)i, digested with ribonuclease t1, and subjected to two-dimensional rna fingerprinting analysis. with the exception of minor variations, each viroid retained its distinctive fingerprint pattern irrespective of the host species from which it was isolated. we conclude that the nucleotide sequences of these viroids are principally ... | 1978 | 16592502 |
| molecular cloning and characterization of potato spindle tuber viroid cdna sequences. | double-stranded cdna has been synthesized from a polyadenylylated potato spindle tuber viroid (pstv) template and inserted in the pst i endonuclease site of plasmid pbr322 by using the oligo(dc).oligo(dg)-tailing procedure. tetracycline-resistant ampicillin-sensitive transformants contained sequences complementary to pstv [(32)p]cdna, and one recombinant clone (pdc-29) contains a 460-base-pair insert. this cloned double-stranded pstv cdna contains the cleavage sites for six restriction endonucle ... | 1980 | 16592877 |
| are viroids escaped introns? | a complex of considerable stability is possible between the 5' end of u1 rna and a specific nucleotide sequence of the potato spindle tuber viroid complement. because base-pairing between the 5' end of u1 rna and the ends of introns is believed by some to be responsible for the precise alignment and correct excision of introns, the u1-related sequence may represent the two ends of a presumed intron ancestor of the viroid complement after circularization. | 1981 | 16593072 |
| longer-than-unit-length viroid minus strands are present in rna from infected plants. | nucleic acids isolated from uninfected and potato spindle tuber viroid-infected rutgers tomato plants were fractionated on agarose gels under two different sets of denaturing conditions and hybridized to (125)i-labeled viroid in a series of blot hybridization experiments. complementary strand nucleic acids detected in extracts of infected plants were heterogeneous in size, with four discrete bands containing molecules approximately 700, 1050, 1500, and 1800 nucleotides long. enzymatic studies in ... | 1981 | 16593104 |
| rna intermediates in potato spindle tuber viroid replication. | two double-stranded rna intermediates of viroid replication have been isolated from potato spindle tuber viroid (pstv)-infected tomato tissue and characterized by polyacrylamide gel electrophoresis and dna-rna hybridization techniques. these replicative intermediates contain monomeric circular or linear pstv strands complexed with a multimeric complementary rna strand. synchronous synthesis of single-stranded pstv is accompained by a simultaneous marked increase in double-stranded pstv rna; thus ... | 1982 | 16593138 |
| mutational analysis of potato spindle tuber viroid reveals complex relationships between structure and infectivity. | viroids are single-stranded, covalently closed circular rna pathogens that can be isolated from certain higher plants afflicted with specific diseases. their small size (246-375 nucleotides; m(r) 0.8-1.3 x 10(5)) and ability to replicate autonomously make viroids a unique model system in which to study the relationships between the structure of an rna and its biological function. the demonstrated infectivity of certain cloned viroid cdnas allows the use of site-specific mutagenesis techniques to ... | 1987 | 16593846 |
| evidence for a single rolling circle in the replication of potato spindle tuber viroid. | we analyzed in vivo-labeled rna to determine which of the two proposed rolling-circle models is more likely to depict the replication cycle of potato spindle tuber viroid. a key feature distinguishing the two models is the presence of a circular monomeric minus strand in one and not the other. chromatography on cellulose cf11 was used to purify a fraction containing the replication intermediates free from single-stranded progeny. heat denaturation followed by gel electrophoresis was used to seek ... | 1988 | 16594003 |
| development and evaluation of a multiplex rt-pcr for detecting main viruses and a viroid of potato. | a multiplex rt-pcr (mrt-pcr) for detecting four potato viruses (potato virus s (pvs), potato virus x (pvx), potato virus y (pvy), and potato leaf roll virus (plrv)) and one potato viroid (potato spindle tuber viroid (pstvd)) was developed. the mrt-pcr consisted of one reaction with specific primers designed according to the sequences of coat protein (cp) genes of respective viruses and the sequence of the viroid. the entire procedure from tissue grinding to rt-pcr results takes about 4 hrs. the ... | 2006 | 16808331 |
| tertiary structural and functional analyses of a viroid rna motif by isostericity matrix and mutagenesis reveal its essential role in replication. | rna-templated rna replication is essential for viral or viroid infection, as well as for regulation of cellular gene expression. specific rna motifs likely regulate various aspects of this replication. viroids of the pospiviroidae family, as represented by the potato spindle tuber viroid (pstvd), replicate in the nucleus by utilizing dna-dependent rna polymerase ii. we investigated the role of the loop e (sarcin/ricin) motif of the pstvd genomic rna in replication. a tertiary-structural model of ... | 2006 | 16912306 |
| evidence for the existence of the loop e motif of potato spindle tuber viroid in vivo. | rna motifs comprising nucleotides that interact through non-watson-crick base pairing play critical roles in rna functions, often by serving as the sites for rna-rna, rna-protein, or rna small ligand interactions. the structures of viral and viroid rna motifs are studied commonly by in vitro, computational, and mutagenesis approaches. demonstration of the in vivo existence of a motif will help establish its biological significance and promote mechanistic studies on its functions. by using uv cro ... | 2007 | 17135317 |
| a structured viroid rna serves as a substrate for dicer-like cleavage to produce biologically active small rnas but is resistant to rna-induced silencing complex-mediated degradation. | rna silencing is a potent means of antiviral defense in plants and animals. a hallmark of this defense response is the production of 21- to 24-nucleotide viral small rnas via mechanisms that remain to be fully understood. many viruses encode suppressors of rna silencing, and some viral rnas function directly as silencing suppressors as counterdefense. the occurrence of viroid-specific small rnas in infected plants suggests that viroids can trigger rna silencing in a host, raising the question of ... | 2007 | 17202210 |
| accumulation of viroid-specific small rnas and increase in nucleolytic activities linked to viroid-caused pathogenesis. | strong viroid-caused pathogenesis was achieved in tomato cv. rutgers by biolistic transfer of severe or lethal potato spindle tuber viroid (pstvd) strains, while other tomato genotypes (e.g., moneymaker) were tolerant. with reciprocal hybrids between sensitive and tolerant genotypes, we show that plant depression dominates over tolerance. biolistic transfer of the most pathogenic pstvd strain as1 to nicotiana benthamiana, which is considered to be a symptomless pstvd host, led to a strong pathog ... | 2007 | 17214544 |
| existence in vivo of the loop e motif in potato spindle tuber viroid rna. | in vitro experiments have previously identified in potato spindle tuber viroid (pstvd), the type member of the nuclear viroids, an element of local tertiary structure termed loop e. here, by direct uv irradiation of pstvd-infected tomato tissue and subsequent rna analysis by denaturing polyacrylamide gel electrophoresis, northern blot hybridization and primer extension, we report that pstvd (+) rna also forms the loop e in vivo. these results provide strong support for the physiological relevanc ... | 2007 | 17370107 |
| structural differences within the loop e motif imply alternative mechanisms of viroid processing. | viroids replicate via a rolling circle mechanism, and cleavage/ligation requires extensive rearrangement of the highly base-paired native structure. for potato spindle tuber viroid (pstvd), the switch from cleavage to ligation is driven by the change from a multibranched tetraloop structure to a loop e conformation. here we present evidence that processing of citrus viroid iii (cvd-iii), a member of a related group of viroids that also replicate in the nucleus, may proceed via a distinct pathway ... | 2007 | 17438124 |
| highly sensitive fluorescent-labeled probes and glass slide hybridization for the detection of plant rna viruses and a viroid. | in this study, a modified method of the conventional rna dot-blot hybridization was established, by replacing (32)p labels with cy5 labels and replacing nylon membranes with positive-charged glass slides, for detecting plant rna viruses and a viroid. the modified rna dot-blot hybridization method was named glass slide hybridization. the optimum efficiency of rna binding onto the surfaces of activated glass slide was achieved using aminosilane-coated glass slide as a solid matrix and 5xsaline sod ... | 2007 | 17492129 |
| tertiary structure and function of an rna motif required for plant vascular entry to initiate systemic trafficking. | vascular entry is a decisive step for the initiation of long-distance movement of infectious and endogenous rnas, silencing signals and developmental/defense signals in plants. however, the mechanisms remain poorly understood. we used potato spindle tuber viroid (pstvd) as a model to investigate the direct role of the rna itself in vascular entry. we report here the identification of an rna motif that is required for pstvd to traffic from nonvascular into the vascular tissue phloem to initiate s ... | 2007 | 17660743 |
| cell-free circularization of viroid progeny rna by an rna ligase from wheat germ. | linear, potato spindle tuber viroid rna has been used as a substrate for an rna ligase purified from wheat germ. linear viroid molecules are efficiently converted to circular molecules (circles) which are indistinguishable by electrophoretic mobility and two-dimensional oligonucleotide pattern from viroid circles extracted from infected plants. in light of recent evidence for multimeric viroid replication intermediates, cleavage followed by rna ligation by a cellular enzyme may (i) be a normal s ... | 1982 | 17740972 |
| transfer of agrobacterium dna to plants requires a t-dna border but not the vire locus. | agrobacterium tumefaciens induces tumors in plants by transferring and integrating oncogenes (t-dna) into the chromosomes of host plant cells. agrobacterium strains were used to transfer complementary dna copies of a potato spindle tuber viroid (pstv) to plant cells at a wound site on tomato plant stems. subsequently, infectious viroid rna was found in the leaves of these plants, indicating systemic pstv infection. this process utilized the t-dna transfer mechanisms of agrobacterium since pstv i ... | 1986 | 17800798 |
| sensitive and rapid diagnosis of potato spindle tuber viroid disease by nucleic acid hybridization. | a sensitive and reliable new method for the detection of potato spindle tuber viroid in potato tubers has been developed. the method is based on hybridization of highly radioactive recombinant dna to viroid rna that has been attached to a solid support. the method can be automated and permits the rapid testing of large numbers of tubers. | 1981 | 17847478 |
| 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 |
| identification and sequence analysis of potyviruses infecting crops in vietnam. | fifty-two virus isolates from 13 distinct potyvirus species infecting crops in vietnam were identified and the 3' region of each genome was sequenced. the viruses were: bean common mosaic virus (bcmv), potato virus y (pvy), sugarcane mosaic virus (scmv), sorghum mosaic virus (srmv), chilli veinal mottle virus (chivmv), zucchini yellow mosaic virus (zymv), leek yellow stripe virus (lymv), shallot yellow stripe virus (sysv), onion yellow dwarf virus (oydv), turnip mosaic virus (tumv), dasheen mosa ... | 2008 | 17906829 |
| successive accumulation of two size classes of viroid-specific small rna in potato spindle tuber viroid-infected tomato plants. | like many plant rna viruses, infection by potato spindle tuber viroid (pstvd) is known to lead to rna silencing and a marked reduction in visible disease. to examine the relationship between rna silencing and this recovery phenomenon in greater detail, we have carried out time-course analyses of viroid-specific small rna accumulation using several viroid-host combinations. these analyses revealed the presence of two size classes of viroid-specific small rnas in infected plants, and sequence anal ... | 2007 | 18024916 |
| 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 |
| nuclear targeting by fragmentation of the potato spindle tuber viroid genome. | transient expression of engineered reporter rnas encoding an intron-containing green fluorescent protein (gfp) from a potato virus x-based expression vector previously demonstrated the nuclear targeting capability of the 359 nucleotide potato spindle tuber viroid (pstvd) rna genome. to further delimit the putative nuclear-targeting signal, pstvd subgenomic fragments were embedded within the intron, and recombinant reporter rnas were inoculated onto nicotiana benthamiana plants. appearance of gre ... | 2008 | 18211806 |
| direct detection of n-h[...]n hydrogen bonds in biomolecules by nmr spectroscopy. | a nuclear magnetic resonance (nmr) experiment is described for the direct detection of n-h[...]n hydrogen bonds (h-bonds) in 15n isotope-labeled biomolecules. this quantitative hnn-cosy (correlation spectroscopy) experiment detects and quantifies electron-mediated scalar couplings across the h-bond (h-bond scalar couplings), which connect magnetically active (15)n nuclei of the h-bond donor and acceptor. detectable h-bonds comprise the imino h-bonds in canonical watson-crick base pairs, many h-b ... | 2008 | 18274526 |
| parallel algorithms for finding a near-maximum independent set of a circle graph. | a parallel algorithm for finding a near-maximum independent set in a circle graph is presented. an independent set in a graph is a set of vertices, no two of which are adjacent. a maximum independent set is an independent set whose cardinality is the largest among all independent sets of a graph. the algorithm is modified for predicting the secondary structure in ribonucleic acids (rna). the proposed system, composed of an n neural network array (where n is the number of edges in the circle grap ... | 1990 | 18282845 |
| in vitro synthesis and characterization of dna complementary to potato spindle tuber viroid. | when dnase-digested calf thymus dna is used as primer, the rna-directed dna polymerase of avian myeloblastosis virus will accept potato spindle tuber viroid (pstv) as a template for dna synthesis. the dna obtained hybridizes specifically to pstv and low molecular weight rna isolated from pstv-infected plants; no hybridization to unrelated viral rnas or tow molecular weight rna isolated from uninoculated host plants was detectable. purified pstv cdna is heterogeneous in length, but the mean chain ... | 1978 | 18627880 |
| measurement of viroid sequence homology by hybridization with complementary dna prepared in vitro. | dna complementary to potato spindle tuber viroid (ystv cdna) has been used in rna dna hybridization experiments to study pstv replication in a variety of hosts and to measure the amount of sequence homology between ystv and several independently isolated viroids. when pstv cdna was hybridized with low molecular weight rna isolated from pstv-infected tomato at different times after inoculation, pstv . pstv cdna hybrids were detectable before symptoms began to appear. low molecular weight rna was ... | 1978 | 18627881 |
| tomato dna contains no detectable regions complementary to potato spindle tuber viroid as assayed by solution and filter hybridization. | a previous report (hadidi et al. (1976) proc. nat. acad. sci. usa73, 2453-2457) has suggested that potato spindle tuber viroid (pstv) rna contains sequences complementary to the dna of its host and, to a lesser extent, to the dna of some nonhost species. our studies indicate, however, that the apparent hybridization between (125)i-labeled pstv and tomato dna which can be observed in both solution and filter hybridization experiments is a consequence of the hybridization of host rnas (mostly ribo ... | 1980 | 18631656 |
| tomato dna contains no detectable regions complementary to potato spindle tuber viroid as assayed by southern hybridization. | dna was isolated from crude nuclear pellets prepared from rutgers tomato plant leaf tissue from both potato spindle tuber viroid (pstv)-infected and uninfected plants. following digestion by the dna restriction enzymes ecori, xbai, or bamhi, the dna was fractionated by agarose gel electrophoresis, transferred to nitrocellulose filters, and incubated with a variety of 125i-labeled rna probes under conditions which permit hybridization. analysis of autoradiogram patterns and fingerprints of the rn ... | 1980 | 18631657 |
| plant cell suspension cultures sustain long-term replication of potato spindle tuber viroid. | cell suspension cultures were established from tomato plants (lycopersicum esculentum cv. "rutgers") infected with either a severe (tps cell line) or a mild (tpm cell line) strain of potato spindle tuber viroid (pstv) and from uninfected plants (th cell line). based on measurements of packed cell volume, the tps line exhibited a slower growth rate than the th line, and reached lower levels of total cell volume during the stationary phase. the tpm line was intermediate between the other two. all ... | 1981 | 18635038 |
| purification and characterization of hop stunt viroid. | the hop stunt viroid (hsv) has been purified from cucumber leaves infected with the hop stunt disease agent. electron microscopic observation of denatured hsv shows a typical viroid rna molecule of covalently closed circular form. the molecular length was estimated to be 290-300 nucleotides by electron microscopic measurement and polyacrylamide gel electrophoresis using potato spindle tuber viroid as a standard. hsv is one of the smallest viroids characterized so far. hsv preparations were separ ... | 1982 | 18635127 |
| comparative sequence and structure of different isolates of citrus exocortis viroid. | the nucleotide sequences of two new australian isolates of citrus exocortis viroid (cev), cev-de25 and cev-de26, have been determined and compared with the previously sequenced australian isolate, cev-a (j. e. visvader, a. r. gould, g. e. breuning, and r. h. symons. febs lett.137, 288-292 (1982).) and a californian isolate, cev-c (h. j. gross, g. krupp, h. domdey, m. raba, p. jank, c. lossow, h. alberty, k. ramm, and h. l. sanger. eur. j. biochem.121, 249-257 (1982).). sequencing of recombinant ... | 1983 | 18639139 |
| cell-free synthesis and processing of an infectious dimeric transcript of potato spindle tuber viroid rna. | a full-length cloned cdna insert containing the sequence of potato spindle tuber viroid (pstv) was dimerized and placed in the plasmid vector psp65 adjacent to a promoter for bacteriophage sp6 rna polymerase. in vitro transcription of this region yielded a single linear rna chain 760 bases in length containing two copies of pstv rna with about 20 bases of vector sequence at each end. bioassay on tomato plants revealed that this transcript has infectivity comparable to that of pstv itself, yieldi ... | 1985 | 18639847 |
| in vivo encapsidation of potato spindle tuber viroid by velvet tobacco mottle virus particles. | when nicotiana clevelandii was inoculated simultaneously with velvet tobacco mottle virus (vtmov) and potato spindle tuber viroid (pstv), replication of the viroid was greatly suppressed. however, both pathogens replicated if pstv was inoculated several days before the vtmov. small amounts of pstv were detected by dot-blot analysis of rna in highly purified vtmov isolated from coinfected plants indicating that the viroid had been encapsidated by the virus particles. moreover, tomato plants which ... | 1986 | 18640657 |
| the nature and biological significance of linear potato spindle tuber viroid molecules. | "naturally occurring" linear potato spindle tuber viroid (pstvl) was shown to be as infectious as circular pstv (pstvc). the occurrence of pstvl was shown not to be (a) an artifact of the extraction procedure per se; (b) due to the presence of metal ions in extraction buffers; or (c) related to the host species used for propagation, to a particular pstv strain, or to the duration of infection. from labeling and blot-hybridization experiments, it was concluded that in infected tissue pstvc appear ... | 1987 | 18644556 |
| oligomeric potato spindle tuber viroid (pstv) rna does not process autocatalytically under conditions where other rnas do. | in vitro-synthesized oligomeric linear rnas representing the replicative intermediates of potato spindle tuber viroid (pstv) were subjected to a large variety of in vitro conditions where self-splicing of group i introns occurs, and where self-cleavage and self-circularization of the satellite rna from tobacco ringspot virus particles and self-cleavage of oligomeric forms of avocado sunblotch viroid rna has been observed. no evidence whatsoever could be obtained that the pstv rna oligomers monom ... | 1987 | 18644557 |
| potato spindle tuber viroid: investigation of the long-distance, intra-plant transport route. | potato spindle tuber viroid (pstv) could be detected in tomato plants by dot-blot hybridization as early as 6-7 days postinoculation (p.i.), approximately 1 week before the appearance of symptoms. the viroid was always first detectable in the shoot tip of the plant and in leaves that were very close to the tip, followed temporally by detection in leaves further from the tip down to and eventually including the inoculated leaf. although pstv also moved down to the roots, it did not move into leav ... | 1987 | 18644563 |
| virulence in murine model shows the existence of two distinct populations of brazilian vaccinia virus strains. | brazilian vaccinia virus had been isolated from sentinel mice, rodents and recently from humans, cows and calves during outbreaks on dairy farms in several rural areas in brazil, leading to high economic and social impact. some phylogenetic studies have demonstrated the existence of two different populations of brazilian vaccinia virus strains circulating in nature, but little is known about their biological characteristics. therefore, our goal was to study the virulence pattern of seven brazili ... | 2008 | 18725979 |
| transfecting protoplasts by electroporation to study viroid replication. | protoplasts have been extensively used to study replication of plant viruses at the cellular level. however, their use in studying viroid replication has been very limited because of various technical barriers. as a result, mechanisms of viroid replication remain poorly understood. the electroporation protocol presented in this unit offers a simple, fast and reproducible method to inoculate protoplasts derived from cultured cells of tobacco (nicotiana tabacum) and the related species nicotiana b ... | 2005 | 18770558 |
| molecular detection of potato spindle tuber viroid in razavi and northern khorasan provinces. | the aim of this study was to identify the potato spindle tuber viroid (pstvd) by reverse transcriptase-pcr. among all plant diseases which are caused by viroids, pstvd was the first viroid which is recognized by plant pathologist. suspended potato tubers from razavi and northern khorasan provinces collected and cultured. leaves of cultured tubers were used for rna extraction by peg6000 precipitation method. subsequent rt-pcr reaction has been carried out using specific primers. a 359 bp fragment ... | 2008 | 18819657 |
| russian isolates of potato spindle tuber viroid. | forty pstvd isolates collected from five regions of russia (north-western, central, volga region, northern caucasus and the far east) were sequenced during 2006-2008. all isolates lacked the adenine residue present at position 123 of the type strain; i.e., pstvd-intermediate (genbank v01465). nineteen russian isolates also contained an adenosine --> cytosine substitution at position 120. twenty two additional unique changes were also observed in one or more of the isolates sequenced. | 2008 | 19226770 |
| rnai-mediated resistance to potato spindle tuber viroid in transgenic tomato expressing a viroid hairpin rna construct. | because of their highly ordered structure, mature viroid rna molecules are assumed to be resistant to degradation by rna interference (rnai). in this article, we report that transgenic tomato plants expressing a hairpin rna (hprna) construct derived from potato spindle tuber viroid (pstvd) sequences exhibit resistance to pstvd infection. resistance seems to be correlated with high-level accumulation of hprna-derived short interfering rnas (sirnas) in the plant. thus, although small rnas produced ... | 2009 | 19523100 |
| modification of tobacco plant development by sense and antisense expression of the tomato viroid-induced agc viiia protein kinase pkv suggests involvement in gibberellin signaling. | the serine-threonine protein kinase gene, designated pkv (protein kinase- viroid induced) was previously found to be transcriptionally activated in tomato plants infected with the plant pathogen potato spindle tuber viroid (pstvd). these plants exhibited symptoms of stunting, and abnormal development of leaf, root, and vascular tissues. the encoded protein, pkv, is a novel member of the agc viiia group of signal-transducing protein kinases; however, the role of pkv in plant development is unknow ... | 2009 | 19689802 |
| distinct rna motifs mediate systemic rna trafficking. | systemic rna trafficking is emerging as a new paradigm in gene regulation at the whole plant level. the mechanisms that ensure delivery of all sorts of rnas to their respective cellular destinations remain poorly understood. several lines of research suggest that specific sequence/structural motif(s) within an rna directs its trafficking. the first motif was identified in potato spindle tuber viroid (pstvd), which mediates trafficking from bundle sheath to mesophyll in young tobacco leaves. our ... | 2008 | 19704772 |
| rna-dependent rna polymerase 6 delays accumulation and precludes meristem invasion of a viroid that replicates in the nucleus. | the detection of viroid-derived small rnas (vd-srnas) similar to the small interfering rnas (sirnas, 21 to 24 nucleotides [nt]) in plants infected by nuclear-replicating members of the family pospiviroidae (type species, potato spindle tuber viroid [pstvd]) indicates that they are inducers and targets of the rna-silencing machinery of their hosts. rna-dependent rna polymerase 6 (rdr6) catalyzes an amplification circuit producing the double-stranded precursors of secondary sirnas. recently, the r ... | 2010 | 20015979 |
| trafficking of the potato spindle tuber viroid between tomato and orobanche ramosa. | viroids, small rna pathogens capable of infecting flowering plants, coexist in the field with parasitic plants that infest many crops. the ability of viroids to be exchanged between host and parasitic plants and spread in the latter has not yet been investigated. we studied the interaction between the potato spindle tuber viroid (pstvd) and branched bromrape (orobanche ramosa) using the tomato, solanum lycopersicon, as a common host. we report the long distance trafficking of pstvd rna via the p ... | 2010 | 20110096 |
| a chimeric satellite transgene sequence is inefficiently targeted by viroid-induced dna methylation in tobacco. | in plants, transgenes containing potato spindle tuber viroid (pstvd) cdna sequences were efficient targets of pstvd infection-mediated rna-directed dna methylation. here, we demonstrate that in pstvd-infected tobacco plants, a 134 bp pstvd fragment (pstvd-134) did not become densely methylated when it was inserted into a chimeric satellite tobacco mosaic virus (stmv) construct. only about 4-5% of all cytosines (cs) of the pstvd-134 were methylated when flanked by satellite sequences. in the same ... | 2010 | 20364297 |
| potato spindle tuber viroid: the simplicity paradox resolved? | taxonomy: potato spindle tuber viroid (pstvd) is the type species of the genus posipiviroid, family pospiviroidae. an absence of hammerhead ribozymes and the presence of a 'central conserved region' distinguish pstvd and related viroids from members of a second viroid family, the avsunviroidae. physical properties: viroids are small, unencapsidated, circular, single-stranded rna molecules which replicate autonomously when inoculated into host plants. because viroids are non-protein-coding rnas, ... | 2007 | 20507521 |
| use of randomly mutagenized genomic cdna banks of potato spindle tuber viroid to screen for viable versions of the viroid genome. | in an effort to study sequence space allowing the recovery of viable potato spindle tuber viroid (pstvd) variants we have developed an in vivo selection (selex) method to produce and bulk-inoculate by agroinfiltration large pstvd cdna banks in which a short stretch of the genome is mutagenized to saturation. this technique was applied to two highly conserved 6 nt-long regions of the pstvd genome, the left terminal loop (tl bank) and part of the polypurine stretch in the upper strand of pre-melti ... | 2010 | 21068216 |
| characterization of plant mirnas and small rnas derived from potato spindle tuber viroid (pstvd) in infected tomato. | to defend against invading pathogens, plants possess rna silencing mechanisms involving small rnas (mirnas, sirnas). also viroids - plant infectious, non-coding, unencapsidated rna - cause the production of viroid-specific small rnas (vsrna), but viroids do escape the cytoplasmic silencing mechanism. viroids with minor sequence variations can produce different symptoms in infected plants, suggesting an involvement of vsrnas in symptom production. we analyzed by deep sequencing the spectrum of vs ... | 2010 | 21087089 |
| trans-cleaving hammerhead ribozymes with tertiary stabilizing motifs: in vitro and in vivo activity against a structured viroid rna. | trans-cleaving hammerheads with discontinuous or extended stem i and with tertiary stabilizing motifs (tsms) have been tested previously against short rna substrates in vitro at low mg(2+) concentration. however, the potential of these ribozymes for targeting longer and structured rnas in vitro and in vivo has not been examined. here, we report the in vitro cleavage of short rnas and of a 464-nt highly structured rna from potato spindle tuber viroid (pstvd) by hammerheads with discontinuous and ... | 2010 | 21097888 |
| ribosomal protein l5 and transcription factor iiia from arabidopsis thaliana bind in vitro specifically potato spindle tuber viroid rna. | potato spindle tuber viroid (pstvd) contains an element of tertiary structure -loop e- also present in eukaryotic 5s rrna. the ribosomal protein l5 and transcription factor iiia (tfiiia) from arabidopsis thaliana bind 5s rrna in vitro and in vivo, mediating different functions that include nucleocytoplasmic transport and transcription activation, respectively. we show that a. thaliana l5 and tfiiia also bind pstvd (+) rna in vitro with the same affinity as they bind 5s rrna, whereas the affinity ... | 2010 | 21153748 |
| a three-dimensional rna motif in potato spindle tuber viroid mediates trafficking from palisade mesophyll to spongy mesophyll in nicotiana benthamiana. | cell-to-cell trafficking of rna is an emerging biological principle that integrates systemic gene regulation, viral infection, antiviral response, and cell-to-cell communication. a key mechanistic question is how an rna is specifically selected for trafficking from one type of cell into another type. here, we report the identification of an rna motif in potato spindle tuber viroid (pstvd) required for trafficking from palisade mesophyll to spongy mesophyll in nicotiana benthamiana leaves. this m ... | 2011 | 21258006 |
| accumulation of potato spindle tuber viroid-specific small rnas is accompanied by specific changes in gene expression in two tomato cultivars. | to better understand the biogenesis of viroid-specific small rnas and their possible role in disease induction, we have examined the accumulation of these small rnas in potato spindle tuber viroid (pstvd)-infected tomato plants. large-scale sequence analysis of viroid-specific small rnas revealed active production from the upper portion of the pathogenicity and central domains, two regions previously thought to be underrepresented. profiles of small rna populations derived from pstvd antigenomic ... | 2011 | 21353278 |
| molecular analysis of the coat protein gene of peanut stripe virus from china. | peanut stripe virus (pstv) is one of the most common viruses infecting peanut that causes great economic losses every year. the 3อด-terminal 1082 bp of 74 pstv isolates collected from 12 districts of shandong province, china were sequenced. their coat protein (cp) genes were 864 bp in length and shared identities of 98.0%~100% and 98.3% ~100% at nt and aa levels. the identities between the cp genes of these isolates and other 36 isolates from the genbank were 93.5%~100% and 92.0%~100% at nt and a ... | 2011 | 21692560 |
| global analysis of tomato gene expression during potato spindle tuber viroid infection reveals a complex array of changes affecting hormone signaling. | viroids like potato spindle tuber viroid (pstvd) are the smallest known agents of infectious disease-small, highly structured, circular rna molecules that lack detectable messenger rna activity, yet are able to replicate autonomously in susceptible plant species. to better understand the possible role of rna silencing in disease induction, a combination of microarray analysis and large-scale rna sequence analysis was used to compare changes in tomato gene expression and microrna levels associate ... | 2012 | 22217247 |
| tomato rna polymerase ii interacts with the rod-like conformation of the left terminal domain of the potato spindle tuber viroid positive rna genome. | potato spindle tuber viroid (pstvd) is a small, single-stranded, circular, non-coding rna pathogen. host dna-dependent rna polymerase ii (rnap ii) was proposed to be critical for its replication, but no interaction site for rnap ii on the pstvd rna genome was identified. using a co-immunoprecipitation strategy involving a mab specific for the conserved heptapeptide (i.e. ysptsps) located at the carboxy-terminal domain of the largest subunit of rnap ii, we established the interaction of tomato rn ... | 2012 | 22422064 |
| deep sequencing of small rnas in tomato for virus and viroid identification and strain differentiation. | small rnas (srna), including micrornas (mirna) and small interfering rnas (sirna), are produced abundantly in plants and animals and function in regulating gene expression or in defense against virus or viroid infection. analysis of sirna profiles upon virus infection in plant may allow for virus identification, strain differentiation, and de novo assembly of virus genomes. in the present study, four suspected virus-infected tomato samples collected in the u.s. and mexico were used for srna libr ... | 2012 | 22623984 |
| plant viroids: isolation, characterization/detection, and analysis. | when diener discovered potato spindle tuber viroid in 1971 (diener, virology 45:411-428, 1971), only a limited number of techniques were available for plant virus detection and purification. biological assays using indicator hosts showing characteristic symptoms of infection and able to support high levels of viroid replication played a critical role in viroid detection and characterization. polyacrylamide gel electrophoresis (page) was the first molecular technique to be used for the rapid (2-3 ... | 2012 | 22678585 |
| viruses of potato. | potatoes are an important crop in mediterranean countries both for local consumption and for export to other countries, mainly during the winter. many mediterranean countries import certified seed potato in addition to their own seed production. the local seeds are mainly used for planting in the autumn and winter, while the imported seed are used for early and late spring plantings. potato virus y is the most important virus in mediterranean countries, present mainly in the autumn plantings. th ... | 2012 | 22682169 |
| viroids: from genotype to phenotype just relying on rna sequence and structural motifs. | as a consequence of two unique physical properties, small size and circularity, viroid rnas do not code for proteins and thus depend on rna sequence/structural motifs for interacting with host proteins that mediate their invasion, replication, spread, and circumvention of defensive barriers. viroid genomes fold up on themselves adopting collapsed secondary structures wherein stretches of nucleotides stabilized by watson-crick pairs are flanked by apparently unstructured loops. however, compellin ... | 2012 | 22719735 |
| analysis of sequence polymorphism and population structure of tomato chlorotic dwarf viroid and potato spindle tuber viroid in viroid-infected tomato plants. | the sequence polymorphism and population structure of tomato chlorotic dwarf viroid (tcdvd) (isolate trust) and potato tuber spindle viroid (pstvd) (isolate fn) in tomato plants were investigated. of the 9 and 35 tcdvd clones sequenced from 2 different tcdvd-infected plants, 2 and 4 sequence variants were identified, respectively, leading to a total of 4 sequence variants of 360 nucleotides in length. variant i was identical to af162131, the first tcdvd sequence to be reported, and the rest exhi ... | 2012 | 22816033 |
| transgenerational maintenance of transgene body cg but not chg and chh methylation. | in plants, rna-directed dna methylation (rddm) can target both transgene promoters and coding regions/gene bodies. rddm leads to methylation of cytosines in all sequence contexts: cg, chg and chh. upon segregation of the rddm trigger, at least cg methylation can be maintained at promoter regions in the progeny. so far, it is not clear whether coding region methylation can be also maintained. we showed that the body of potato spindle tuber viroid (pstvd) transgene constructs became densely de nov ... | 2012 | 22863736 |
| viroid rna redirects host dna ligase 1 to act as an rna ligase. | viroids are a unique class of noncoding rnas: composed of only a circular, single-stranded molecule of 246-401 nt, they manage to replicate, move, circumvent host defenses, and frequently induce disease in higher plants. viroids replicate through an rna-to-rna rolling-circle mechanism consisting of transcription of oligomeric viroid rna intermediates, cleavage to unit-length strands, and circularization. though the host rna polymerase ii (redirected to accept rna templates) mediates rna synthesi ... | 2012 | 22869737 |
| a single polyprobe for detecting simultaneously eight pospiviroids infecting ornamentals and vegetables. | the spread of viroids belonging to the genus pospiviroid (family pospiviroidae), recorded recently in ornamentals and vegetables in several european countries, calls for fast, efficient and sensitive detection methods. based on bioinformatics analyses of sequence identity among all pospiviroids, a digoxigenin-labeled polyprobe (pospiprobe) was developed that, when tested by dot-blot and northern-blot hybridization, detected potato spindle tuber viroid, citrus exocortis viroid, columnea latent vi ... | 2012 | 22935607 |
| biological and molecular analysis of the pathogenic variant c3 of potato spindle tuber viroid (pstvd) evolved during adaptation to chamomile (matricaria chamomilla). | viroid-caused pathogenesis is a specific process dependent on viroid and host genotype(s), and may involve viroid-specific small rnas (vsrnas). we describe a new pstvd variant c3, evolved through sequence adaptation to the host chamomile (matricaria chamomilla) after biolistic inoculation with pstvd-kf440-2, which causes extraordinary strong ('lethal') symptoms. the deletion of a single adenine a in the oligoa stretch of the pathogenicity (p) domain appears characteristic of pstvd-c3. the pathog ... | 2012 | 22944665 |
| development and validation of a real-time rt-pcr assay for generic detection of pospiviroids. | in many countries phytosanitary regulations apply to potato spindle tuber viroid, because it can cause serious diseases in potato and tomato crops. other pospiviroids, some of which are distributed widely in ornamental crops, can cause similar diseases. consequently, there is a need for a reliable and cost-effective generic testing method. an assay was developed that detects all known species of the genus pospiviroid, using real-time rt-pcr based on taqman technology. this genpospi assay consist ... | 2013 | 22981990 |
| dicer-like 4 but not dicer-like 2 may have a positive effect on potato spindle tuber viroid accumulation in nicotiana benthamiana. | 2013 | 23100483 | |
| dahlia latent viroid: a recombinant new species of the family pospiviroidae posing intriguing questions about its origin and classification. | a viroid-like rna has been detected in two asymptomatic dahlia accessions by return and double page. it appeared smaller than chrysanthemum stunt viroid and potato spindle tuber viroid, the two members of the genus pospiviroid, family pospiviroidae, reported in this ornamental previously. rt-pcr with primers designed for amplifying all pospiviroids produced no amplicons, but rt-pcr with random primers revealed a 342 nt rna. the sequence of this rna was confirmed with specific primers, which addi ... | 2013 | 23255620 |
| a novel application of methacrylate based short monolithic columns: concentrating potato spindle tuber viroid from water samples. | potato spindle tuber viroid (pstvd) is the causal agent of a number of agriculturally important diseases. it is a single-stranded, circular and unencapsidated rna molecule with only 356-360 nucleotides and no coding capacity. because of its peculiar structural features, it is very stable ex vivo and it is easily transmitted mechanically by contaminated hands, tools, machinery, etc. in this work, we describe the development and optimization of a method for concentrating pstvd using convective int ... | 2012 | 23298847 |
| scion on a stock producing sirnas of potato spindle tuber viroid (pstvd) attenuates accumulation of the viroid. | plants can attenuate the replication of plant viruses and viroids by rna silencing induced by virus and viroid infection. in higher plants, silencing signals such as small interfering rnas (sirnas) produced by rna silencing can be transported systemically through phloem, so it is anticipated that antiviral sirna signals produced in a stock would have the potential to attenuate propagation of viruses or viroids in the scion. to test whether this is indeed the case, we prepared transgenic tobacco ... | 2013 | 23469061 |
| [molecular properties of potato spindle tuber viroid (pstvd) isolates from the collection of the russian research institute of phytopathology]. | the complete nucleotide sequences of more than 100 isolates of pstvd collected from locations in the territory of russia and the former ussr have been determined. these sequences represent 42 individual sequence variants, each containing 1-10 mutations with respect to the "intermediate" or type strain of pstvd (genbank acc. no. v01465). isolates containing 2-5 mutations were the most common, and 24 sequence variants are described here for the first time. twenty one isolates contained a mutation ... | 2013 | 23705498 |
| photosynthetically active suspension cultures of potato spindle tuber viroid infected tomato cells as tools for studying viroid - host cell interaction. | photosynthetically active callus and cell suspension cultures were established from uninfected lycopersicon peruvianum plants and from uninfected and potato spindle tuber viroid (pstvd) infected plants of lycopersicon esculentum cv. rutgers. viroid infection was maintained in photoheterotrophic culture on media containing 3% sucrose, but during continuous photo-mixotrophic culture in low sucrose media (1% sucrose), the level of pstvd accumulation decreased. photoautotrophic cell suspensions coul ... | 1993 | 24201870 |
| a bromodomain-containing host protein mediates the nuclear importation of a satellite rna of cucumber mosaic virus. | replication of the satellite rna (satrna) of cucumber mosaic virus is dependent on replicase proteins of helper virus (hv). however, we recently demonstrated that like with potato spindle tuber viroid (pstvd), a satrna associated with cucumber mosaic virus strain q (q-satrna) has the propensity to localize in the nucleus and generate multimers that subsequently serve as templates for hv-dependent replication. but the mechanism regulating the nuclear importation of q-satrna is unknown. here we sh ... | 2014 | 24284314 |
| site-specific mutagenesis of potato spindle tuber viroid cdna: : alterations within premelting region 2 that abolish infectivity. | the infectivity of cloned viroid cdnas permits investigation of structure/function relationships in these unusual pathogenic rnas by systematic site-specific mutagenesis of the cdnas and subsequent bioassay. we have used three different strategies to create nucleotide substitutions within premelting region 2, a region of potato spindle tuber viroid (pstv) believed to be important in viroid replication: sodium bisulfitecatalyzed deamination of deoxycytosine residues, oligonucleotide-directed muta ... | 1986 | 24307277 |
| potato spindle tuber viroid infections mediated by the ti plasmid of agrobacterium tumefaciens. | full length copies of potato spindle tuber viroid (pstv) were introduced into plant cells using an agrobacterium tumefaciens vector. crown galls containing the pstv dna were induced on tomato plants, and the plants analysed for systemic replication of the viroid. two separately derived multimeric pstv insertions in the t-dna were infectious on every plant inoculated. however, monomeric pstv gave rise to significant levels of infection only when an adjacent plant promoter could direct transcripti ... | 1986 | 24307321 |
| contitions for optimal growth of a pstv-infected potato cell suspension and detection of viroid-complementary longer-than-unit-length rna in these cells. | a suspension culture from potato spindle tuber viroid (pstv)-infected cells of the wild type potato (solanum demissum) has been established, which is a suitable model system for studying pstv replicationin vivo. the conditions for rapid growth of these cells and for permanent extensive viroid biosynthesis within them are described. biosynthesis of pstv in the potato cells was demonstrated by(32)p-incorporation into nucleic acids and their subsequent electrophoretic analysis on polyacrylamide gel ... | 1983 | 24318372 |
| small rna analysis of potato spindle tuber viroid infected phelipanche ramosa. | plants defend themselves against virus/viroid infection by induction of a mechanism of viral rna degradation or translation inhibition. this is achieved by the production of small rnas referred to as small interfering rnas and microrna, the key molecules in establishment of rna directed silencing. potato spindle tuber viroid (pstvd) was the first viroid species to be identified as naturally infecting potato, and it was found to infect many other crop species, wild and ornamental plants. recently ... | 2014 | 24326144 |
| survival and transmission of potato virus y, pepino mosaic virus, and potato spindle tuber viroid in water. | hydroponic systems and intensive irrigation are used widely in horticulture and thus have the potential for rapid spread of water-transmissible plant pathogens. numerous plant viruses have been reported to occur in aqueous environments, although information on their survival and transmission is minimal, due mainly to the lack of effective detection methods and to the complexity of the required transmission experiments. we have assessed the role of water as a source of plant infection using three ... | 2014 | 24334672 |
| application of a modified edta-mediated exudation technique and guttation fluid analysis for potato spindle tuber viroid rna detection in tomato plants (solanum lycopersicum). | potato spindle tuber viroid (pstvd) is a small plant pathogenic circular rna that does not encode proteins, replicates autonomously, and traffics systemically in infected plants. long-distance transport occurs by way of the phloem; however, one report in the literature describes the presence of viroid rna in the xylem ring of potato tubers. in this study, a modified method based on an edta-mediated phloem exudation technique was applied for detection of pstvd in the phloem of infected tomato pla ... | 2014 | 24388932 |
| in nicotiana species, an artificial microrna corresponding to the virulence modulating region of potato spindle tuber viroid directs rna silencing of a soluble inorganic pyrophosphatase gene and the development of abnormal phenotypes. | potato spindle tuber viroid (pstvd) is a small non-protein-coding rna pathogen that can induce disease symptoms in a variety of plant species. how pstvd induces disease symptoms is a long standing question. it has been suggested that pstvd-derived small rnas (srnas) could direct rna silencing of a targeted host gene(s) resulting in symptom development. to test this, we expressed pstvd sequences as artificial micrornas (amirnas) in nicotiana tabacum and nicotiana benthamiana. one amirna, amir46 t ... | 2014 | 24503090 |
| comparing mirnas and viroids; highly conserved molecular mechanisms for the transmission of genetic information. | 2014 | 24600348 | |
| simultaneous detection of rna and dna targets based on multiplex isothermal amplification. | the detection of pathogenic microorganisms present in food, feed, plant, and other samples is important for providing safe food as well as for preventing the spread of microbes. the genome of pathogens is made of dna or rna, therefore a multiplex diagnostics tool would ideally be able to amplify and detect both rna and dna targets in parallel. with this goal we have developed an isothermal nucleic acid sequence based amplification [nasba] implemented microarray analysis (naima) procedure, suitab ... | 2014 | 24625323 |
| survey and analysis of simple sequence repeats (ssrs) present in the genomes of plant viroids. | extensive simple sequence repeat (ssr) surveys have been performed for eukaryotic prokaryotic and viral genomes, but information regarding ssrs in viroids is limited. we undertook a survey to examine the presence of ssrs in viroid genomes. our results show that the distribution of ssrs in viroids may influence secondary structure, and that ssrs could play a role in generating genetic diversity. we also discuss the potential evolutionary role of repeated sequences in the viroid genome. this is th ... | 2014 | 24649400 |
| specific argonautes selectively bind small rnas derived from potato spindle tuber viroid and attenuate viroid accumulation in vivo. | the identification of viroid-derived small rnas (vd-srnas) of 21 to 24 nucleotides (nt) in plants infected by viroids (infectious non-protein-coding rnas of just 250 to 400 nt) supports their targeting by dicer-like enzymes, the first host rna-silencing barrier. however, whether viroids, like rna viruses, are also targeted by the rna-induced silencing complex (risc) remains controversial. at the risc core is one argonaute (ago) protein that, guided by endogenous or viral srnas, targets complemen ... | 2014 | 25100851 |