Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
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| replicating potato spindle tuber viroid rna is accompanied by short rna fragments that are characteristic of post-transcriptional gene silencing. | the low molecular weight fraction of tomato plants inoculated with potato spindle tuber viroid (pstvd) contains a population of short pstvd-specific rnas of either polarity. the main constituents were rnas of 22 and 23 nt representing different domains of the viroid genome. the occurrence of such distinct rna species indicated that the nuclear replicating pstvd rna induces post-transcriptional gene silencing. the short rnas were slightly more abundant at 30 days post-inoculation than at later st ... | 2001 | 11376158 |
| the variability of hop latent viroid as induced upon heat treatment. | we have previously shown that heat treatment of hop plants infected by hop latent viroid (hlvd) reduces viroid levels. here we investigate whether such heat treatment leads to the accumulation of sequence variability in hlvd. we observed a negligible level of mutated variants in hlvd under standard cultivation conditions. in contrast, the heat treatment of hop led to hlvd degradation and, simultaneously, to a significant increase in sequence variations, as judged from temperature gradient-gel el ... | 2001 | 11531412 |
| rna folding pathway functional intermediates: their prediction and analysis. | the massively parallel genetic algorithm (ga) for rna structure prediction uses the concepts of mutation, recombination, and survival of the fittest to evolve a population of thousands of possible rna structures toward a solution structure. as described below, the properties of the algorithm are ideally suited to use in the prediction of possible folding pathways and functional intermediates of rna molecules given their sequences. utilizing stem trace, an interactive visualization tool for rna s ... | 2001 | 11545583 |
| binding of ire-bp to its cognate rna sequence: sfm studies on a universal rna backbone for the analysis of rna-protein interaction. | we have used an rna consisting of the potato spindle tuber viroid (pstvd) and 240 bp of double-stranded rna derived from the gus gene as a backbone for scanning force microscope (sfm) studies on rna binding proteins. the in vitro transcribed rna forms a rod-like structure of apparent 130 nm in length with a completely base paired central part flanked by the incompletely paired viroid helix with bulges on both sides. the termini of the molecule consist of loops such that no blunt or staggered rna ... | 2001 | 11592396 |
| transcription of potato spindle tuber viroid by rna polymerase ii starts predominantly at two specific sites. | pospiviroidae, with their main representative potato spindle tuber viroid (pstvd), are replicated via a rolling circle mechanism by the host-encoded dna-dependent rna polymerase ii (pol ii). in the first step, the (+)-strand circular viroid is transcribed into a (-)-strand oligomer intermediate. as yet it is not known whether transcription is initiated by promotors at specific start sites or is distributed non-specifically over the whole circle. an in vitro transcription extract was prepared fro ... | 2001 | 11713308 |
| genetic variability of potato spindle tuber viroid rna replicon. | the genetic continuity of the potato spindle tuber viroid (pstvd) genome was analysed after infection of tomato plants with cloned cdnas of parental strains. during the six weeks of the experiment, several new sequence variants appeared. the sequence variants detected in the progeny population induced sequence-specific disease symptoms. the pstvd genome therefore follows the pattern expected for typical pseudo-strains propagating in plants as a population of similar sequences. assessing further ... | 2001 | 11732616 |
| potato spindle tuber viroid as inducer of rna silencing in infected tomato. | potato spindle tuber viroid (pstvd), an rna plant pathogen encoding no known proteins, induces systemic symptoms on tomato plants. we report detection of small rnas of approximately 25 nucleotides with sequence specificity to pstvd in infected plants: an indication of the presence of rna silencing. rna silencing, however, did not appear to be responsible for the differing symptoms induced by a mild and a severe strain of pstvd. the unique structural and biological features of viroids make them a ... | 2001 | 11763132 |
| control of mechanical viroid transmission by the disinfection of tables and tools. | viroids are of practical importance as the cause of several economically significant infectious diseases. potato spindle tuber viroid (pstvd) causes severe yield losses in several crops, because the pathogen spreads fast within the culture. viroids are small molecules, a few hundred nucleotides long, with a high degree of secondary structure. they do not code for any polypeptides and replicate independently of any associated plant virus. viroids are readily transmitted by contaminated tools and ... | 2001 | 12425031 |
| potato spindle tuber viroid strains of different pathogenicity induces and suppresses expression of common and unique genes in infected tomato. | viroids are the smallest plant pathogens. these rnas do not encode proteins and are not encapsidated, and yet they can replicate autonomously, move systemically, and cause diseases in infected plants. notably, strains of a viroid with subtle differences in nucleotide sequences can cause dramatically different symptoms in infected plants. these features make viroids unique probes to investigate the role of a pathogenic rna genome in triggering host responses. we conducted a comprehensive analysis ... | 2002 | 12437296 |
| replication of potato spindle tuber viroid in cultured cells of tobacco and nicotiana benthamiana: the role of specific nucleotides in determining replication levels for host adaptation. | we have developed an electroporation protocol to inoculate cultured cells of tobacco and nicotiana benthamiana with in vitro transcripts of potato spindle tuber viroid (pstvd) to characterize viroid structural features that determine replication efficiency at the cellular level. both (+)- and (-)-strands of pstvd were detected by northern blots as early as 6 h postinoculation (h.p.i.). accumulation of the (+)-circular pstvd increased very rapidly starting at 24 h.p.i. and continued beyond 6 days ... | 2002 | 12441088 |
| production of anti-virus, viroid plants by genetic manipulations. | many pathogenic plant viruses are rna viruses, which initiate production of double-stranded rna intermediates when they replicate in host plant cells. introduction of double-stranded rna-specific ribonucleases such as the schizosaccharomyces pombe derived pac i protein and animal cell derived interferon-induced 2',5'-oligoadenylate synthetase (2-5 aase)/ribonuclease l (rnase l) system into various plants may make plants resistant to various pathogenic viruses and viroids. we have demonstrated th ... | 2002 | 12449532 |
| bean common mosaic virus isolates causing different symptoms in asparagus bean in china differ greatly in the 5'-parts of their genomes. | potyvirus isolates from asparagus bean ( vigna sesquipedalis) plants in zhejiang province, china, caused either rugose and vein banding mosaic symptoms (isolate r) or severe yellowing (isolate y) in this host, but were otherwise similar in host range. both isolates were completely sequenced and shown to be isolates of bean common mosaic virus (bcmv). the complete sequences were 9992 (r) or 10062 (y) nucleotides long and shared 91.7% identical nucleotides (93.2% identical amino acids) in their ge ... | 2002 | 12111434 |
| detection and analysis of hairpin ii, an essential metastable structural element in viroid replication intermediates. | in (-)-stranded replication intermediates of the potato spindle tuber viroid (pstvd) a thermodynamically metastable structure containing a specific hairpin structure (hp ii) has been proposed to be essential for viroid replication. in the present work a method was devised allowing the direct detection of the hp ii structure in vitro and in vivo using a biophysical approach. an rna oligonucleotide was constructed which specifically binds to the hp ii loop region in transient (-)-strand intermedia ... | 2002 | 12140319 |
| a novel multiplex rt-pcr probe capture hybridization (rt-pcr-elisa) for simultaneous detection of six viroids in four genera: apscaviroid, hostuviroid, pelamoviroid, and pospiviroid. | a rapid and sensitive assay was developed for the detection and identification of viroids by standard or multiplex reverse transcription-polymerase chain reaction (rt-pcr)-probe capture hybridization (rt-pcr-elisa). the assay was applied successfully for the detection and identification of the following six viroid species from infected tissues: potato spindle tuber viroid (pospiviroid), peach latent mosaic viroid (pelamoviroid), apple scar skin viroid (apscaviroid), apple dimple fruit viroid (ap ... | 2002 | 12176148 |
| movement of potato spindle tuber viroid reveals regulatory points of phloem-mediated rna traffic. | increasing evidence indicates that the phloem mediates traffic of selective rnas within a plant. how an rna enters, moves in, and exits the phloem is poorly understood. potato spindle tuber viroid (pstvd) is a pathogenic rna that does not encode proteins and is not encapsidated, and yet it replicates autonomously and traffics systemically within an infected plant. the viroid rna genome must interact directly with cellular factors to accomplish these functions and is, therefore, an excellent prob ... | 2002 | 12226494 |
| plant 7sl rna and trna(tyr) genes with inserted antisense sequences are efficiently expressed in an in vitro transcription system from nicotiana tabacum cells. | rna polymerase iii-driven cassettes for the expression of antisense rnas and ribozymes have recently attracted much attention because (1) pol iii genes are transcribed abundantly in all kinds of tissues and (2) the transcripts are very stable by virtue of their small and compact size. we have designed two types of pol iii-based expression vehicles. antisense rna sequences targeted against conserved structural elements or domains in the rnas of potato spindle tuber viroid, hop latent viroid and p ... | 2002 | 12374302 |
| a mini-rna containing the tetraloop, wobble-pair and loop e motifs of the central conserved region of potato spindle tuber viroid is processed into a minicircle. | a mini-rna from potato spindle tuber viroid (pstvd) was constructed specifically for cleavage and ligation to circles in vitro. it contains the c-domain with the so-called central conserved region (ccr) of pstvd with a 17 nt duplication in the upper strand and hairpin structures at the left and rights ends of the secondary structure. the ccr was previously shown to be essential for processing of in vitro transcripts. when folded under conditions which favor formation of a kinetically controlled ... | 2003 | 12560495 |
| viroid rna systemic spread may depend on the interaction of a 71-nucleotide bulged hairpin with the host protein virp1. | viroids are noncoding circular single-stranded rnas that are propagated systemically in plants. virp1 is a protein from tomato, which is an excellent host for potato spindle tuber viroid (pstvd), and it has been isolated by virtue of its specific in vitro binding to pstvd rna. we report on the specific in vivo interaction of virp1 with full-length viroid rna as well as with subfragments in the three-hybrid system. the terminal right domain (tr) of pstvd was identified as a strong interacting par ... | 2003 | 12592008 |
| identification of neutral mutants surrounding two naturally occurring variants of potato spindle tuber viroid. | single point mutations in the pathogenicity domain of potato spindle tuber viroid (pstvd) can have a dramatic effect on disease expression, and only three substitutions are required for the spontaneous conversion of the type strain pstvd-intermediate to the rapidly replicating, highly pathogenic variant rg1 (gruner et al., virology 209, 60-69, 1995). to identify available evolutionary pathways linking these two variants, we mutagenized five positions in an infectious cdna copy of pstvd-intermedi ... | 2003 | 12604828 |
| inhibition of cell growth and shoot development by a specific nucleotide sequence in a noncoding viroid rna. | viroids are small noncoding and infectious rnas that replicate autonomously and move systemically throughout an infected plant. the rnas of the family pospiviroidae contain a central conserved region (ccr) that has long been thought to be involved in replication. here, we report that the ccr of potato spindle tuber viroid (pstvd) also plays a role in pathogenicity. a u257a change in the ccr converted the intermediate strain pstvd(int) to a lethal strain that caused severe growth stunting and pre ... | 2003 | 12782729 |
| biochemical analysis and scanning force microscopy reveal productive and nonproductive adar2 binding to rna substrates. | scanning force microscopy (sfm) can be used to image biomolecules at high resolution. here we demonstrate that single-molecule analysis by sfm complements biochemical data on rna protein binding and can provide information that cannot be obtained by the usual biochemical methods. we have used this method to study the interaction between the rna editing enzyme adar2 and rna transcripts containing selective and nonselective editing sites. the natural selectively edited r/g site from glutamate rece ... | 2003 | 12810917 |
| a bromodomain-containing protein from tomato specifically binds potato spindle tuber viroid rna in vitro and in vivo. | for the identification of rna-binding proteins that specifically interact with potato spindle tuber viroid (pstvd), we subjected a tomato cdna expression library prepared from viroid-infected leaves to an rna ligand screening procedure. we repeatedly identified cdna clones that expressed a protein of 602 amino acids. the protein contains a bromodomain and was termed viroid rna-binding protein 1 (virp1). the specificity of interaction of virp1 with viroid rna was studied by different methodologie ... | 2003 | 12915580 |
| identification of a novel structural interaction in columnea latent viroid. | pairwise sequence comparisons suggest that columnea latent viroid (clvd) may have originated from a recombination event involving potato spindle tuber viroid (pstvd) and hop stunt viroid (hsvd). to examine the role of specific structural features in determining the host range of clvd, we constructed a series of interspecific chimeras by replacing increasing portions of its terminal left and pathogenicity domains with the corresponding portions of pstvd. exchanges involving the left side of the p ... | 2003 | 12954225 |
| characterization of the rna motif responsible for the specific interaction of potato spindle tuber viroid rna (pstvd) and the tomato protein virp1. | viroids are small non-coding parasitic rnas that are able to infect their host plants systemically. this circular naked rna makes use of host proteins to accomplish its proliferation. here we analyze the specific binding of the tomato protein virp1 to the terminal right domain of potato spindle tuber viroid rna (pstvd). we find that two asymmetric internal loops within the pstvd (+) rna, each composed of the sequence elements 5'-acagg and cucuucc-5', are responsible for the specific rna-protein ... | 2003 | 14500815 |
| differential subnuclear localization of rna strands of opposite polarity derived from an autonomously replicating viroid. | the wide variety of rnas produced in the nucleus must be localized correctly to perform their functions. however, the mechanism of this localization is poorly understood. we report here the differential subnuclear localization of rna strands of opposite polarity derived from the replicating potato spindle tuber viroid (pstvd). during replication, (+)- and (-)-strand viroid rnas are produced. we found that in infected cultured cells and plants, the (-)-strand rna was localized in the nucleoplasm, ... | 2003 | 14555700 |
| resistance of human hepatitis delta virus rnas to dicer activity. | the endonuclease dicer cleaves rnas that are 100% double stranded and certain rnas with extensive but <100% pairing to release approximately 21-nucleotide (nt) fragments. circular 1,679-nt genomic and antigenomic rnas of human hepatitis delta virus (hdv) can fold into a rod-like structure with 74% pairing. however, during hdv replication in hepatocytes of human, woodchuck, and mouse origin, no approximately 21-nt rnas were detected. likewise, in vitro, purified recombinant dicer gave <0.2% cleav ... | 2003 | 14581527 |
| structural characterization of the 69 nucleotide potato spindle tuber viroid left-terminal domain by nmr and thermodynamic analysis. | the 69 nucleotide left-terminal domain (t(l)) of the potato spindle tuber rna viroid (pstvd) constitutes one of its five structural elements. due to a twofold complementary sequence repeat, two possible conformations are proposed for the t(l) secondary structure; an elongated-rod and a bifurcated form. in the present study, two t(l) mutants were designed that remove the symmetry of the sequence repeats and ensure that either the bifurcated or the elongated-rod conformation is thermodynamically f ... | 2003 | 14636600 |
| development of a real-time rt-pcr assay for the detection of potato spindle tuber viroid. | potato spindle tuber viroid (pstvd) is a quarantine pathogen in the european union and causes damaging diseases of solanaceous crops. under the eu plant health directive 2000/29/ec, countries must have the ability to detect and identify accurately and rapidly the introduction of harmful organisms in plants or plant products; furthermore, if the quarantine pathogen is found, be able to survey extensively for it. in this respect, pstvd poses an interesting technical problem, since its rna does not ... | 2004 | 14738980 |
| an rt-pcr primer pair for the detection of pospiviroid and its application in surveying ornamental plants for viroids. | a primer pair for reverse transcription-polymerase chain reaction (rt-pcr), based on the conserved sequences of the members of genus pospiviroid was designed to yield a fragment of about 200 base pairs (bp). since pospiviroids infect a large number of plants species and a few members of the genus pospiviroid have been already detected in some ornamental plants, the primer pair was evaluated for its efficacy using ornamental plants. the method of return-polyacrylamide gel electrophoresis (r-page) ... | 2004 | 14738987 |
| short interfering rnas specific for potato spindle tuber viroid are found in the cytoplasm but not in the nucleus. | short interfering (si) and micro (mi) rnas influence gene expression at post-transcriptional level. in plants, different classes of dicer-like (dcl) enzymes are responsible for the generation of these small regulatory rnas from different precursors. to characterize the cellular site of their generation and accumulation, we purified nuclei from tomato plants infected with potato spindle tuber viroid (pstvd) rna, which is known to replicate in the nucleus via double-stranded (ds) rna intermediates ... | 2004 | 14871315 |
| on the role of rna silencing in the pathogenicity and evolution of viroids and viral satellites. | viroids and most viral satellites have small, noncoding, and highly structured rna genomes. how they cause disease symptoms without encoding proteins and why they have characteristic secondary structures are two longstanding questions. recent studies have shown that both viroids and satellites are capable of inducing rna silencing, suggesting a possible role of this mechanism in the pathology and evolution of these subviral rnas. here we show that preventing rna silencing in tobacco, using a sil ... | 2004 | 14978267 |
| viroid-induced rna silencing of gfp-viroid fusion transgenes does not induce extensive spreading of methylation or transitive silencing. | viroid infection is associated with the production of short interfering rnas (sirnas), a hallmark of post-transcriptional gene silencing (ptgs). however, viroid rnas autonomously replicating in the nucleus have not been shown to trigger the degradation of homologous rna in the cytoplasm. to investigate the potential of viroids for the induction of gene silencing, non-infectious fragments of potato spindle tuber viroid (pstvd) cdna were transcriptionally fused to the 3' end of the green fluoresce ... | 2004 | 15053764 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| the discovery and eradication of potato spindle tuber viroid in canada. | in 1960s, potato spindle tuber was thought to be a viral disease. in 1971, the agent of the disease was characterised as a low-molecular weight infectious ribonucleic acid (rna), which was named as 'viroid', specifically potato spindle tuber viroid (pstvd)). since then, more than 30 plant diseases in horticultural and ornamental plants have been shown to be caused by different viroids globally. viroids are single-stranded rna, covalently closed circular molecule, without any protein coat. they a ... | 2014 | 25674616 |
| distribution of potato spindle tuber viroid in reproductive organs of petunia during its developmental stages. | embryo infection is important for efficient seed transmission of viroids. to identify the major pattern of seed transmission of viroids, we used in situ hybridization to histochemically analyze the distribution of potato spindle tuber viroid (pstvd) in each developmental stage of petunia (flowering to mature seed stages). in floral organs, pstvd was present in the reproductive tissues of infected female × infected male and infected female × healthy male but not of healthy female × infected male ... | 2014 | 25116641 |
| 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 |
| comparing mirnas and viroids; highly conserved molecular mechanisms for the transmission of genetic information. | 2014 | 24600348 | |
| 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 |
| 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 |