| evidence for a single infectious species of potato spindle tuber viroid. | potato spindle tuber viroid (pstv) has been separated into two electrophoretic species on polyacrylamide gels containing 8 m urea at 60 degrees. only the slower-migrating electrophoretic form was infectious and is presumably the circular form of the molecule. both forms had similar base compositions with a 55-58% gc content, similar to the citrus exocortis viroid. labeling studies in vivo suggest that the viroid is not methylated. | 1979 | 429145 |
| properties of rna polymerases of healthy and citrus exocortis viroid-infected gynura aurantiaca dc. | | 1976 | 1258361 |
| the sequence of a viroid from grapevine closely related to severe isolates of citrus exocortis viroid. | the primary structure of a grapevine viroid (gvs) isolated in spain was determined. the sequence consisted of 369 nucleotide residues forming a circular molecule. gvs presented extensive homology with viroids of the potato spindle tuber viroid (pstv) group, that was specially high in the case of citrus exocortis viroid (cev) both with variants found in isolates inducing severe (92% with cev-a) and mild (89% with cev-de26) symptoms on tomato. the secondary structure proposed for gvs showed that t ... | 1987 | 2438653 |
| degradation of tomato pathogenesis-related proteins by an endogenous 37-kda aspartyl endoproteinase. | as a response to the stress induced by different afflicting agents, tomato plants (lycopersicon esculentum) produce the so-called 'pathogenesis-related' proteins. here we report the degradation of some of these proteins by a constitutive endoproteolytic activity that co-distributes with pathogenesis-related proteins in the intercellular spaces of tomato leaves infected with citrus exocortis viroid. this endoproteinase was purified, showing a ph optimum of 2.5-3.5, a mr of 37,000 and selective in ... | 1989 | 2680484 |
| functional distinctions between the ribonucleic acids from citrus exocortis viroid and plant viruses: cell-free translation and aminoacylation reactions. | | 1974 | 4609218 |
| a citrus exocortis viroid variant from broad bean (vicia faba l.): infectivity and pathogenesis. | a viroid present in very low titres was isolated from symptomless field broad bean plants. it was identified as a variant of citrus exocortis viroid in the t2, v and c domains. infection of several hosts resulted in a change in the composition of the viroid population. serial passage through tomato and back to the host of origin, broad bean, resulted in major changes in replication efficiency, host range and pathogenicity. the unique nucleotide sequence differences identified in the original bro ... | 1995 | 7561764 |
| detection of citrus exocortis viroid in crude extracts by dot-blot hybridization: conditions for reducing spurious hybridization results and for enhancing the sensitivity of the technique. | dot-blot assays to detect citrus exocortis viroid (cev), in clarified sap and unfractionated total nucleic acid preparations of cev-infected gynura aurantiaca and chrysanthemum, were impaired by the non-specific binding of the radioactive probe shown by the healthy controls. this non-specific background was considerably reduced by the addition to the hybridization mixture, of the fraction of nucleic acids from healthy plants which are insoluble in 2 m licl (containing mainly the large ribosomal ... | 1986 | 3755443 |
| indian bunchy top disease of tomato plants is caused by a distinct strain of citrus exocortis viroid. | a viroid has been isolated from tomato plants affected by indian bunchy top disease of tomato (lycopersicon esculentum mill.). in dot blot hybridization assays with 32p-labelled crna probes specific for the detection of various viroids, the indian viroid was shown to be most closely related to the citrus exocortis viroid (cevd). sequence determination showed that the viroid consists of 372 nucleotides and confirmed its close relationship with cevd. the viroid, for which we propose the acronym ce ... | 1991 | 1875190 |
| isolates of citrus exocortis viroid recovered by host and tissue selection. | isolates of citrus exocortis viroid (cev) from a single sweet orange citrus source have been selected by sequential passage through the alternative hosts citron, gynura aurantiaca, a hybrid tomato lycopersicon esculentum x l. peruvianum, and from disorganized callus culture of the hybrid tomato. the distinctions in symptom expression, titre and electrophoretic mobility among the cev isolates, operationally termed cevc (citron), cevg (gynura), cevt (tomato) and cevcls (callus) are supported by ch ... | 1993 | 8245858 |
| relationships among the viroids derived from grapevines. | there have been numerous reports of grapevine viroids, describing physical and biological properties suggestive of similar or identical molecular forms. with consideration of these properties and the application of random-primed and specific cdna probes, four major groups of grapevine viroids have been defined. designations which can be used to describe distinct viroids within the four groups include (i) cevd-g, a grapevine isolate of citrus exocortis viroid, (ii) gvd-c, a grapevine viroid recov ... | 1992 | 1607864 |
| cdna cloning of viroid-induced tomato pathogenesis-related protein p23. characterization as a vacuolar antifungal factor. | a 23-kd pathogenesis-related protein (p23) is induced in tomato (lycopersicon esculentum mill, cv rutgers) plants when infected with citrus exocortis viroid. this protein is homologous to the salt-induced tomato np24 protein (i. rodrigo, p. vera, r. frank, v. conejero [1991] plant mol biol 16: 931-934). further characterization of p23 has shown that this protein accumulates in vacuoles in association with dense inclusion bodies. in vitro assays indicated that the purified p23 protein inhibits th ... | 1993 | 8278538 |
| calorimetric studies on viroids. | thermodynamic studies on highly purified viroid preparations were carried out with the help of a very sensitive adiabatic microcalorimeter. parallel to the change of uv-absorption at 260 nm as a function of temperature, the additional heat capacity of the dilute viroid solution rises sharply within the melting interval, reaches a maximum at t = tm and declines to a baseline again when the temperature is increased further. from the peak area the molar transition enthalpy can be calculated. the tr ... | 1978 | 662694 |
| citrus exocortis viroid: survey of protein synthesis in xenopus laevis oocytes following addition of viroid rna. | | 1977 | 560084 |
| a stable 463 nucleotide variant of citrus exocortis viroid produced by terminal repeats. | an unusual variant of citrus exocortis viroid (cev) was detected when an inoculum source from gynura aurantiaca d.c. was used to infect a hybrid tomato (lycopersicon esculentum mill. x l. peruvianum). the 92 nucleotide larger variant, cev d-92, which displayed the characteristic circular and linear viroid structural forms, contained two repeated sequences spanning the v and t2 domains. a dramatic moderation of symptom expression in gynura accompanied the incorporation of these repeated sequences ... | 1994 | 8151291 |
| nucleotide sequence and secondary structure of citrus exocortis and chrysanthemum stunt viroid. | the complete nucleotide sequence of citrus exocortis viroid (cev, propagated in gymura) and chrysanthemum stunt viroid (csv, propagated in cineraria) has been established, using labelling in vitro and direct rna sequencing methods and a new screening procedure for the rapid selection of suitable rna fragments from limited digests. the covalently closed circular single-stranded viroid rnas consist of 371 (cev) and 354 (csv) nucleotides, respectively. as previously shown for potato spindle tuber v ... | 1982 | 7060550 |
| genes encoding acidic and basic class iii beta-1,3-glucanases are expressed in tomato plants upon viroid infection. | beta-1,3-glucanases are hydrolytic enzymes considered to constitute part of the general array of defense genes induced by pathogen infection in higher plants. we have isolated and characterized two complementary dna clones, corresponding to new beta-1,3-glucanases from tomato plants (lycopersicon esculentum) which are expressed upon challenge with citrus exocortis viroid. amino acid sequence comparison revealed that they are most similar to beta-1,3-glucanases from tobacco, particularly to pr-q' ... | 1994 | 8193297 |
| interactions between citrus exocortis and potato spindle tuber viroids in plants of gynura aurantiaca and lycopersicon esculentum. | plants of gynura aurantiaca and tomato (lycopersicon esculentum) were inoculated with severe strains of citrus exocortis viroid (cev) and potato spindle tuber viroid (pstv). the progeny of both viroids was analyzed by two systems of page which allowed discrimination between cev and pstv on the basis of their different sizes. when inoculated separately to g. aurantiaca cev and pstv induced severe and very mild symptoms, respectively, with cev accumulating to a higher level than pstv, whereas when ... | 1989 | 2722468 |
| the 7s rna from tomato leaf tissue resembles a signal recognition particle rna and exhibits a remarkable sequence complementarity to viroids. | from tomato leaf tissue we sequenced and characterized a 7s rna which consists of 299 nucleotides with either two or three additional uridine nucleotides at its 3'-terminus. about 56% of the nucleotides of this higher plant 7s rna are in nearly identical positions as those of the human 7sl rna which is an integral component of the signal recognition particle (srp) that mediates protein translocation. computer modelling and digestion studies with nucleases led to a secondary structure model for t ... | 1988 | 2468486 |
| isolation of three viroids and a circular rna from grapevines. | analysis of nucleic acids from grapevine tissues by two-dimensional gel electrophoresis demonstrated the presence of two bands of circular rna. the smaller rna contained about 300 nucleotide residues and was identified as hop stunt viroid by nucleotide sequencing. the larger rna band was a mixture of species and contained similar amounts of two components, referred to as rna 1a and rna 1b, and in addition a trace amount of citrus exocortis viroid (cev) which became detectable only after inoculat ... | 1988 | 2448417 |
| construction of novel viroid chimeras containing portions of tomato apical stunt and citrus exocortis viroids. | several novel tomato apical stunt viroid (tasv) recombinants were isolated after inoculation of tomato seedlings with monomeric viroid cdnas. two intraspecific recombinants were constructed by exchanging the left and right sides of the closely related ivory coast and indonesian strains of tasv, and a third, interspecific, recombinant was constructed by similar manipulations involving tasv and citrus exocortis viroid (cev) cdnas. characterization of these tasv recombinants by rna protection assay ... | 1990 | 2309444 |
| in vitro synthesis of an infectious viroid: analysis of the infectivity of monomeric linear cev. | infectious monomers of citrus exocortis viroid (cev) were synthesized in vitro precisely to predetermined sequences in microgram quantities without resorting to cloning procedures. amplification of cev double-stranded cdnas fused with a t7 rna polymerase promoter was followed by transcription of the dna resulting in the production of an infectious linear cev monomer. this is the first demonstration of an infectious unit length viroid synthesized in vitro. transcripts containing 3'-oh terminal gr ... | 1992 | 1727598 |
| simultaneous detection of six citrus viroids and apple stem grooving virus from citrus plants by multiplex reverse transcription polymerase chain reaction. | we developed a multiplex reverse transcription polymerase chain reaction (rt-pcr) to detect six citrus viroids: citrus exocortis viroid (cevd), citrus bent leaf viroid (cblvd), hop stunt viroid (hsvd), citrus viroid iii (cvd-iii), citrus viroid iv (cvd-iv) and citrus viroid os (cvd-os) and apple stem grooving virus (asgv, synonym: citrus tatter leaf virus (ctlv)) from citrus plants. the multiplex rt-pcr was also designed to distinguish cvd-i-lss (a distinct variant of cblvd) from cblvd. by the m ... | 2002 | 12393154 |
| comparative oligonucleotide fingerprints of three plant viroids. | 5' phosphorylation in vitro with gamma-32p-atp and t4 phage induced polynucleotide kinase was used to obtain rnaase a and rnaase t1 fingerprints of three plant viroids: potato spindle tuber viroid from tomato (pstv-tom), chrysanthemum stunt viroid from cineraria (chsv-cin) and citrus exocortis viroid from gynura aurantiaca (cev-gyn). these three viroids differ significantly from each other as judged from their oligonucleotide patterns. this supports the concept of individual viroid species. | 1977 | 896482 |
| identification of a new pathogen-induced member of the subtilisin-like processing protease family from plants. | by using biochemical, immunological, and molecular strategies we have identified and cloned a cdna encoding a protease from tomato (lycopersicon esculentum) plants (p69b) that is part of a proteolytic system activated in the plant as a result of infection with citrus exocortis viroid. this new protease is closely related, in terms of amino acid sequence and structural organization, to the previously identified pathogenesis-related subtilisin-like protease (tornero, p., conejero, v., and vera, p. ... | 1997 | 9162080 |
| infectivity of linear monomeric transcripts of citrus exocortis viroid: terminal sequence requirements for processing. | infectivity of linear monomeric viroid rna transcripts is known to be dependent on the site of cloning of the viroid and the viroid and vector sequences at the termini of the rna transcripts. we report here the further characterization of cloning site and sequence requirements using 11 different monomeric cdna constructs of citrus exocortis viroid; these differed from one another by the site of cloning and by nonviroid residues adjacent to the 5' and 3' termini of the viroid sequence in the rna ... | 1994 | 8053157 |
| aligning genomes with inversions and swaps. | the decision about what operators to allow and how to charge for these operations when aligning strings that arise in a biological context is the decision about what model of evolution to assume. frequently the operators used to construct an alignment between biological sequences are limited to deletion, insertion, or replacement of a character or block of characters, but there is biological evidence for the evolutionary operations of exchanging the positions of two segments in a sequence and th ... | 1994 | 7584391 |
| in vitro 32p-labelling of viroid rna for hybridization studies. | a method is described for the in vitro labelling of viroid rna for use in hybridization studies. the citrus exocortis viroid (approximately 350 nucleotides) is degraded by hot formamide hydrolysis to fragments ranging from small oligonucleotides to near full lengths, and subsequently labelled to high specific activity by enzymatically attaching 32p to the 5'-end of each molecule. the cleavage step leaves 5' hydroxyl groups which allows the polynucleotide kinase to directly label the rna fragment ... | 1980 | 7276126 |
| enhanced detection of viroid-rna after selective divalent cation fractionation. | treatment of nucleic acid preparations from citrus exocortis viroid infected tissues with ca2+, co2+, mn2+, and zn2+ results in rapid precipitation of all large rna molecules and selective precipitation of low-molecular-weight rna species. analysis of the viroid-rna by polyacrylamide gel electrophoresis is greatly enhanced in the absence of any additional treatment with 2 m licl. the ratio of circular to linear molecules as well as the relative infectivity of mn2+ -treated viroid preparations re ... | 1983 | 6660503 |
| sequence-specific priming of the in vitro synthesis of dna complementary to citrus exocortis viroid. | | 1981 | 6169553 |
| dot-blot procedure with [32p]dna probes for the sensitive detection of avocado sunblotch and other viroids in plants. | avocado sunblotch viroid (asbv) has been detected down to a level of about 20 pg per gram fresh weight of leaves by the use of a dot-blot hybridization procedure and partially purified nucleic acid extracts. three [32p]dna probes were compared, two prepared from full-length asbv clones in the single-strand m13mp93 vector and the other by primer extension on purified asbv. all three probes gave the same sensitivity of detection of asbv. the methods developed have also been used successfully for t ... | 1985 | 3980666 |
| citrus exocortis viroid rna is associated with the largest subunit of rna polymerase ii in tomato in vivo. | an active replication complex of citrus exocortis viroid (cev) was isolated as a chromatin-enriched fraction of infected tomato leaf with cev rna synthesis activity. this activity was solubilised from the chromatin with ammonium sulphate, but not with sarkosyl. nucleoprotein complexes in the soluble fraction which bound to a monoclonal antibody to the carboxy terminal domain of the largest subunit of rna polymerase ii (8wg16) were affinity purified and contained plus- and minus-sense cev rna. th ... | 1999 | 10664390 |
| genetic variation and population structure of an isolate of citrus exocortis viroid (cevd) and of the progenies of two infectious sequence variants. | the population structure and diversity within a citrus exocortis viroid (cevd) isolate was estimated by single strand conformation polymorphism (sscp) and sequence analysis. a predominant sequence variant (v1) representing 52.8% of the overall population was identified. v1 and other additional variants presented a composition of the p domain characteristic of severe strains of cevd. the nucleotide diversity of this cevd population was lower than expected according to a model of neutral evolution ... | 2005 | 15959832 |
| synthetic oligonucleotide hybridization probes to diagnose hop stunt viroid strains and citrus exocortis viroid. | four species of synthetic oligonucleotide probes for the diagnosis of hop stunt viroid (hsv) and citrus exocortis viroid (cev) were devised. probe hsv-1 detected all the members of hsv group, such as hsv-hop, hsv-grapevine, hsv-cucumber, hsv-citrus and a viroid-like rna isolated from plum trees affected by plum dapple fruit disease. probe hsv-2 discriminated hsv-grapevine from the other members of hsv group. hsv-hop and hsv-grapevine consist of the same numbers of nucleotides, with only one nucl ... | 1988 | 3366851 |
| eleven new sequence variants of citrus exocortis viroid and the correlation of sequence with pathogenicity. | full-length double-stranded cdna was prepared from purified circular rna of two new australian field isolates of citrus exocortis viroid (cev) using two synthetic oligodeoxynucleotide primers. the cdna was then cloned into the phage vector m13mp9 for sequence analysis. sequencing of nine cdna clones of isolate cev-de30 and eleven cdna clones of isolate cev-j indicated that both isolates consisted of a mixture of viroid species and led to the discovery of eleven new sequence variants of cev. thes ... | 1985 | 2582367 |
| identification of the viroid-induced tomato pathogenesis-related (pr) protein p23 as the thaumatin-like tomato protein np24 associated with osmotic stress. | p23, a 23 kda pathogenesis-related (pr) protein, was purified from citrus exocortis viroid (cevd)-infected tomato leaves. partial amino acid sequencing of this protein including the n-terminal and nine additional tryptic fragments covering about 50% of its primary structure revealed extensive homologies to the members of the family of plant thaumatin-like proteins. sequence alignment revealed that tomato p23 is the previously described np24 protein found to be associated to osmotic stress in tom ... | 1991 | 1859873 |
| characterization of lrp, a leucine-rich repeat (lrr) protein from tomato plants that is processed during pathogenesis. | this paper describes the isolation and characterization of lrp, a new gene from tomato plants. the deduced amino acid sequence showed that the encoded protein is enriched in leucine, and contains interesting structural motifs. lrp contains four tandem repeats of a canonical 24 amino acid leucine-rich repeat (lrr) sequence present in different proteins that mediates molecular recognition and/or interaction processes. genomic organization and intron-exon arrangement of lrp favor the hypothesis tha ... | 1996 | 8771787 |
| viroids are single-stranded covalently closed circular rna molecules existing as highly base-paired rod-like structures. | viroids are uncoated infectious rna molecules pathogenic to certain higher plants. four different highly purified viroids were studied. by ultracentrifugation, thermal denaturation, electron microscopy, and end group analysis the following features were established: (i) the molecular weight of cucumber pale fruit viroid from tomato is 110,000, of citrus exocortis viroid from gynura 119,000, of citrus exocortis viroid from tomato 119,000 and of potato spindle tuber viroid from tomato 127,000. (ii ... | 1976 | 1069269 |
| a rapid and sensitive dot-blot hybridization assay for the detection of citrus exocortis viroid in citrus medica with digoxigenin-labelled rna probes. | a rapid and sensitive dot-blot hybridization assay using in vitro-transcribed digoxigenin-labelled rna probes (riboprobes) was developed aiming at detection of citrus exocortis viroid (cevd) in crude sap of infected citrus medica plants. the protocol includes a very quick and simple preparation of rna extracts from samples using a denaturation step with formaldehyde. from our results, the employment of this step is highly recommended because the hybridization signals in formaldehyde-denatured sa ... | 1996 | 8801232 |
| 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 |
| immunogold localization of the citrus exocortis viroid-induced pathogenesis-related proteinase p69 in tomato leaves. | citrus exocortis viroid induces in tomato plants (lycopersicon esculentum) synthesis and accumulation of a pathogenesis-related protein (p69) previously reported to be a proteinase (vera p, conejero v [1988] plant physiol 87: 58-63). by immunogold/transmission electron microscopy, we have studied the distribution of this protein in thin sections of parenchymatous leaf tissue. the enzyme was present intra- and extracellularly. the intracellular location was limited to the vacuole and was always a ... | 1989 | 16666981 |
| rna silencing as related to viroid induced symptom expression. | evidence of post-transcriptional gene silencing (ptgs) in avocado infected by avocado sunblotch viroid (asbvd), the type species of family avsunviroidae, was suggested by detection of asbvd-specific 22-nucleotide rnas. ptgs was observed in infected bleached and variegated symptomatic tissues as well as symptomless carrier foliar sources and fruit with typical sunblotch disease lesions. tissues with the different symptom expressions, characterized by the presence of different predominant asbvd va ... | 2004 | 14745603 |
| development of a one tube-one step rt-pcr protocol for the detection of seven viroids in four genera: apscaviroid, hostuviroid, pelamoviroid and pospiviroid. | a one tube-one step rt-pcr was developed for the detection of seven viroids (apple scar skin viroid, apple dimple fruit viroid, pear blister canker viroid, hop stunt viroid, chrysanthemum stunt viroid, citrus exocortis viroid and peach latent mosaic viroid) in four genera that infect eight plant species. the efficiency and specificity of this method were optimized by the use of moloney-murine leukemia virus (m-mlv) reverse-transcriptase and hotstartaq dna polymerase which allowed increase sensit ... | 2004 | 15350729 |
| single-strand conformation polymorphism (sscp) analysis as a tool for viroid characterisation. | the potential of routine single-strand conformation polymorphism (sscp) analysis for viroid characterization has been evaluated. electrophoresis of 311 cloned full length viroid dna inserts recovered from a field isolate of citrus exocortis viroid (cevd) showed shifts in the migration of the cdna or/and hdna strands in non-denaturing 14% polyacrylamide gels. using a single set of electrophoresis conditions seven different groups of variants (containing one to six changes), which did not represen ... | 1999 | 10029322 |
| host-directed processing of citrus exocortis viroid. | prolonged infection of tomato hybrid (lycopersicon esculentum x lycopersicon peruvianum) by citrus exocortis viroid (cevd) resulted in viroid-like enlarged structures, detected by gel electrophoresis. this population included two new enlarged variants or d-variants, d-87 and d-76, and three transient species or d-forms, d-38, d-40 and d-43. sequence analyses exposed a locus near the terminal repeat region where major changes appeared consistently. in transmission tests to cevd hosts, a variety o ... | 2005 | 15659768 |
| induction of gentisic acid 5-o-beta-d-xylopyranoside in tomato and cucumber plants infected by different pathogens. | tomato plants infected with the citrus exocortis viroid exhibited strongly elevated levels of a compound identified as 2,5-dihydroxybenzoic acid (gentisic acid, ga) 5-o-beta-d-xylopyranoside. the compound accumulated early in leaves expressing mild symptoms from both citrus exocortis viroid-infected tomato, and prunus necrotic ringspot virus-infected cucumber plants, and progressively accumulated concomitant with symptom development. the work presented here demonstrates that ga, mainly associate ... | 2006 | 16321412 |
| infectivity and in vitro mutagenesis of monomeric cdna clones of citrus exocortis viroid indicates the site of processing of viroid precursors. | monomeric cdna clones of citrus exocortis viroid (cev) were constructed in the plasmid vector psp6-4 and the infectivity of the clones plus in vitro-synthesized rna transcripts determined by inoculation onto tomato seedlings. infectivity was dependent on the site of the viroid molecule used for cloning and the orientation of the cdna insert. only the plus bamhi cdna clone was infectious and produced progeny viroid with wild-type sequence at the region corresponding to the bamhi cloning site. inf ... | 1985 | 2994014 |
| restoration of secondary hairpin ii is associated with restoration of infectivity of a non-viable recombinant viroid. | mutagenesis and/or construction of recombinants by exchange of genomic regions between parental molecules constitute powerful tools for the study of viroids. however, a large proportion of such modifications results in molecules, which have lost their infectivity. such is the case for a recombinant viroid named cecs, obtained by replacing the right half of a citrus exocortis viroid (cevd) by the same region from chrysanthemum stunt viroid (csvd). in an effort to recover viable infectious progeny ... | 2001 | 11311425 |
| characterization of a new citrus viroid species tentatively termed citrus viroid os. | a new viroid was obtained from a viroid sample, named 'os', collected from a citrus plant. the viroid consists of 330-331 nucleotides, contains the central conserved region (ccr) characteristic of the genus apscaviroid, and has the highest sequence similarity (only 68%) with citrus iii viroid (cvd-iii) among known viroids. this viroid, by itself, caused only mild petiole necrosis and characteristically very mild leaf bending in arizona 861-s1 etrog citrons (citrus medica l.), the degree of which ... | 2001 | 11448034 |
| properties of the complementary rna sequences associated with infection by the citrus exocortis viroid. | the citrus exocortis disease, caused by the low molecular weight viroid rna, has recently been shown to include viroid complementary rna in nucleic acid extracts. purification procedures indicate the presence of viroid complementary sequences in both 2 m licl precipitate and 2 m licl supernatant fractions. these complementary sequences are detected in preparations from both the high and the low molecular weight regions of polyacrylamide gels. this population heterogeneity coupled with the subcel ... | 1980 | 18631806 |
| some properties of the viroid inducing peach latent mosaic disease. | analysis by polyacrylamide gel electrophoresis of nucleic acid extracts from different peach samples, healthy or infected with the peach latent mosaic (plm) disease, demonstrated the association of this disease with an rna exhibiting the electrophoretic properties typical of circular viroid molecules. this rna was called peach latent mosaic viroid (plmv), since a purified preparation of it, when inoculated into gf 305 peach seedlings induced characteristic symptoms of plm disease. plmv was estim ... | 1990 | 2326551 |
| the persistence of engineered agrobacterium tumefaciens in agroinfected plants. | several plant species, including tomato (lycopersicon esculentum), gynura aurantiaca, avocado (persea americana), and grapefruit (citrus paradisi) grafted on troyer citrange (poncirus trifoliata x c. sinensis) were "agro-infected" with agrobacterium tumefaciens strain lba-4404, carrying a mini-ti plasmid with a dimeric cdna of citrus exocortis viroid (cevd). extracts prepared from tissues of the agroinfected plants 38-90 days after inoculation were plated on selective media and found to contain ... | 1993 | 8274776 |
| the expression of antisense and ribozyme genes targeting citrus exocortis viroid in transgenic plants. | four ribozyme and antisense genes targeting citrus exocortis viroid (cevd) positive- and negative-strand rna molecules were constructed and used to transform the tomato lycopersicon lycopersicum cv. uc82b. the tomato is a readily transformable plant and will support replication of cevd following mechanical inoculation. the ribozyme genes contained three hammerhead catalytic motifs with long hybridizing arms and synthetic rna transcripts were shown to cleave the target cevd rna molecule in vitro. ... | 1995 | 9049383 |
| polyamines in plants infected by citrus exocortis viroid or treated with silver ions and ethephon. | the levels of polyamines in leaves of gynura aurantiaca dc and tomato, lycopersicon esculentum mill. cv rutgers, infected with citrus exocortis viroid (cevd) or treated with silver nitrate or ethephon (2-chloroethylphosphonic acid) were measured by hplc in relation to development of symptoms. previously it had been demonstrated that treatment of g. aurantiaca plants with silver nitrate or ethephon closely mimicked the effects of viroid infection in the plants. in the studies reported here, a mar ... | 1991 | 16668297 |
| construction of a multiprobe for the simultaneous detection of viroids infecting citrus trees. | infections with different viroid species are common among cultivated fruit trees and grapevines, and many old-clone citrus varieties contain up to five citrus viroids (cvds) within a single tree. this paper describes the construction of a cvd-multiprobe consisting of full-length clones of hop stunt viroid, citrus exocortis viroid, citrus bent leaf viroid and cvd-iii. the cvd-multiprobe was tested against rna transcripts of the four viroids and rna extracts from plants singly infected with cevd o ... | 2006 | 16990999 |
| arabidopsis thaliana has the enzymatic machinery for replicating representative viroid species of the family pospiviroidae. | viroids, subviral noncoding rnas, replicate, move, and incite diseases in plants. viroids replicate through a rolling-circle mechanism in which oligomeric rnas of one or both polarities are cleaved and ligated into the circular monomers. attempts to transmit viroids to arabidopsis have failed for unknown reasons. to tackle this question, arabidopsis was transformed with cdnas expressing dimeric (+) transcripts of representative species of the families pospiviroidae and avsunviroidae, which repli ... | 2004 | 15096616 |
| molecular characterization of cevd strains that induce different phenotypes in gynura aurantiaca: structure-pathogenicity relationships. | two citrus exocortis viroid isolates (cevd-s and cevd-129) that induce severe and mild symptoms in gynura aurantiaca, respectively, have been characterized. they present nucleotide sequences in the pathogenicity motifs p(l), c and p(r) similar to those of "class a" and "class b". infectivity and symptom expression in g. aurantica and tomato were evaluated with a selection of sequence variants recovered from both isolates. as expected, the two variants selected from cevd-s induced severe symptoms ... | 2007 | 17393070 |
| effect of citrus hosts on the generation, maintenance and evolutionary fate of genetic variability of citrus exocortis viroid. | citrus exocortis viroid (cevd) populations are composed of closely related haplotypes whose frequencies in the population result from the equilibrium between mutation, selection and genetic drift. the genetic diversity of cevd populations infecting different citrus hosts was studied by comparing populations recovered from infected trifoliate orange and sour orange seedling trees after 10 years of evolution, with the ancestral population maintained for the same period in the original host, etrog ... | 2009 | 19403756 |
| metabolic response of tomato leaves upon different plant-pathogen interactions. | plants utilise various defence mechanisms against their potential biotic stressing agents such as viroids, viruses, bacteria or fungi and abiotic environmental challenges. among them metabolic alteration is a common response in both compatible and incompatible plant-pathogen interactions. however, the identification of metabolic changes associated with defence response is not an easy task due to the complexity of the metabolome and the plant response. to address the problem of metabolic complexi ... | 2010 | 19866456 |
| characterization of small rnas derived from citrus exocortis viroid (cevd) in infected tomato plants. | in plants, rna silencing provides an adaptive immune system that inactivates pathogenic nucleic acids, guided by 21-24-mer rnas of pathogen origin. the characterization of pathogen-related small rnas (srnas) is relevant to uncovering the strategies used by pathogens to evade host defense responses. several groups have reported the detection of viroid-derived srnas during infections, although the origin of these srnas and their chemical characteristics were poorly understood. here, we describe th ... | 2007 | 17559901 |
| 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 |
| citrus exocortis viroid: nucleotide sequence and secondary structure of an australian isolate. | | 1982 | 15768484 |
| salicylic acid is involved in the basal resistance of tomato plants to citrus exocortis viroid and tomato spotted wilt virus. | tomato plants expressing the nahg transgene, which prevents accumulation of endogenous salicylic acid (sa), were used to study the importance of the sa signalling pathway in basal defence against citrus exocortis viroid (cevd) or tomato spotted wilt virus (tswv). the lack of sa accumulation in the cevd- or tswv-infected nahg tomato plants led to an early and dramatic disease phenotype, as compared to that observed in the corresponding parental money maker. addition of acibenzolar-s-methyl, a ben ... | 2016 | 27893781 |
| the question of citrus viroid iv as a cocadviroid. | it has been suggested that citrus viroid iv (cvd-iv) be classified as a species within the genus cocadviroid. this relationship was based on the presence of a terminal conserved hairpin (tch) and absence of a terminal conserved region (tcr) as specific structural motifs in common with isolates of coconut cadang-cadang viroid (cccvd) as well as phylogenetic relationships with members of the genus cocadviroid. evidence is presented for a "vestigial" tcr in cvd-iv as well as the introduction of the ... | 2005 | 15821974 |
| replication of in vitro constructed viroid mutants: location of the pathogenicity-modulating domain of citrus exocortis viroid. | sequence variants from field isolates of citrus exocortis viroid (cev) that cause either mild or severe symptoms on tomato plants have previously been classified into two groups, a and b. these groups differ primarily in two domains, p(l) and p(r), of the proposed native structure. infectivity studies with full-length cdna clones of variants from each class have now directly confirmed the original correlation between class a sequences and the severe phenotype and between class b sequences and th ... | 1986 | 16453700 |
| citrus exocortis viroid (cev): protein alterations in different hosts following viroid infection. | polyacrylamide-sds protein profiles of different cev-hosts (gynura aurantiaca dc, tomato, potato, and "etrog" citron) as altered by the viroid infection are presented. a common feature of leaf protein alteration patterns of all hosts is the intensification of two low molecular weight protein bands (gynura aurantiaca dc and "etrog" citron cev-p1: 13,700 daltons and cev-p2:18,000 daltons; tomato and potato cev-p2:12,000 daltons and cev-p2:16,300 daltons) analogous to those described for cev-infect ... | 1979 | 18631606 |
| cevd-induced symptom modification as a response to a host-specific temperature-sensitive reaction. | natural selection of two new variants of citrus exocortis viroid (cevd) was detected by observing tissues displaying both severe and mild symptoms from a single gynura aurantiaca. the variants cevd-s (severe) and cevd-m (mild), differing by only five nucleotides confined to the pathogenic (p) domain, remained stable when propagated by rooted cuttings or from successive plants inoculated with tissue extracts or transcripts from cdna clones. cevd-s induces a very severe reaction in gynura that is ... | 2001 | 11162825 |
| rna sequences complementary to citrus exocortis viroid in nucleic acid preparations from infected gynura aurantiaca. | molecular hybridization with (125)i-labeled citrus exocortis viroid rna has been used to survey nucleic acid preparations from gynura aurantiaca for viroid complementary molecules. a differential hybridization effect was detected between nucleic acid extracts from healthy and infected tissue in which significant rnase-resistant (125)i-labeled citrus exocortis viroid resulted in hybridization studies with the infected tissue extracts. subsequent characterization indicated that rna from infected t ... | 1978 | 16592500 |
| characterization of a viroid associated with avocado sunblotch disease. | a viroid has been purified from avocado leaves infected by sunblotch disease and designated the avocado sunblotch viroid. it is a covalently closed circular rna molecule with a molecular weight lower than that of chrysanthemum stunt viroid and citrus exocortis viroid while hybridization analysis with 32p-labeled complementary dna indicated that it is a single rna species. it could be detected as a stainable rna band on polyacrylamide tube gel electrophoresis of partially purified extracts of onl ... | 1979 | 18631620 |
| properties of cell cultures containing the citrus exocortis viroid. | cell and protoplast-derived callus and suspension cultures from healthy and citrus exocortis viroid (cev)-infected tomato tissue have been established. the growth rates of cev-containing cells is not affected by the presence of the viroid. in addition, the viroid-containing cells demonstrate a higher temperature tolerance for growth. the cell wall structure of infected tissue apparently differs from healthy cells as suggested by the differential release of protoplasts and the increased yields of ... | 1982 | 18638807 |
| correlation between ornithine decarboxylase and putrescine in tomato plants infected by citrus exocortis viroid or treated with ethephon. | we have investigated the arginine decarboxylase (adc, ec 4.1.1.19) and ornithine decarboxylase (odc, ec 4.1.1.17) activities and the levels of conjugated polyamines to explain the decrease of free putrescine level caused by citrus exocortis viroid (cevd) and ethephon treatment in tomato (lycopersicon esculentum mill. cv rutgers) plants (j.m. belles, j. carbonell, v. conejero [1991] plant physiol 96: 1053-1059). this decrease correlates with a decrease in odc activity in cevd-infected or ethephon ... | 1993 | 12231879 |
| 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 |
| regulation of gibberellin 20-oxidase gene expression and gibberellin content in citrus by temperature and citrus exocortis viroid. | a cdna clone coding for a gibberellin (ga) 20-oxidase ( ccga20ox1), an enzyme of ga biosynthesis, which when expressed in vitro catalyzed the conversion of ga(12) to ga(9) and of ga(53) to ga(20), was isolated from the citrus hybrid carrizo citrange (c itrus sinensis x poncirus trifoliata). transcripts of ccga20ox1 were abundant in the apex and leaves and much less abundant in internodes, nodes and roots. seedlings of carrizo citrange cultured under a 32 degrees c/27 degrees c (day/night) regime ... | 2003 | 14520571 |
| properties of a cell-free system for synthesis of citrus exocortis viroid. | partially purified nuclei from citrus exocortis viroid (cev)-infected gynura aurantiaca are able to synthesize linear and circular viroid molecules. pretreatment of the nuclei with actinomycin d or deoxyribonuclease did not affect viroid synthesis, whereas the synthesis of other cellular rnas was severely reduced. these observations support the essential role of cev complementary rna sequences in viroid replication. however, when alpha-amanitin was included in this in vitro synthesis system, cev ... | 1982 | 16593239 |
| optimal conditions for cell-free synthesis of citrus exocortis viroid and the question of specificity of rna polymerase activity. | cell-free synthesis of citrus exocortis viroid (cev) in nuclei-rich preparations from infected gynura aurantiaca was optimum at 18-24 degrees c. incubation of reaction mixtures at higher temperatures (30-36 degrees c) resulted in an increase of cev linear molecules and the recovery of incomplete or nicked newly synthesized rna species. although the mg(2+) optimum (2.5-5 mm) for cev synthesis was lower than that for total [(32)p]cmp incorporation (10 mm), the response to mn(2+) ion was distinctly ... | 1984 | 16593489 |
| identification in eggplant of a variant of citrus exocortis viroid (cevd) with a 96 nucleotide duplication in the right terminal region of the rod-like secondary structure. | analysis of eggplants, kept for years under greenhouse conditions after having been mechanically inoculated with nucleic acid preparations from field-grown eggplants containing two viroids, eggplant latent viroid (elvd) and citrus exocortis viroid (cevd), revealed the presence of an additional larger viroid rna. molecular characterization of this rna showed that it is a stable 467-nt variant of cevd with a 96-nt duplication of the right terminal region (cevd-d96) that preserves the rod-like seco ... | 2003 | 14602207 |
| pathogenesis-related proteins of tomato : p-69 as an alkaline endoproteinase. | an endoproteinase induced by citrus exocortis viroid has been purified from tomato (lycopersicon esculentum mill, cv "rutgers") leaves. the proteinase corresponds to one of the major pathogenesis-related proteins of tomato plants and was designated proteinase p-69 as it has a molecular weight of 69,000 to 70,000. the proteinase was purified in four steps: (nh(4))(2)so(4) fractionation, chromatography on bio-gel p-60, deae-sepharose chromatography, and casein-sepharose affinity chromatography. th ... | 1988 | 16666127 |
| multiple citrus viroids in citrus from japan and their ability to produce exocortis-like symptoms in citron. | abstract sequential polyacrylamide gel electrophoresis analyses showed many viroid-like rnas in samples collected from citrus trees in japan. reverse transcription polymerase chain reaction and sequencing analyses of the amplified fragments verified that they were derived from variants of six citrus viroids, citrus exocortis viroid (cevd), citrus bent leaf viroid (cblvd) including cvd-i-lss (a distinct variant of cblvd), hop stunt viroid, citrus viroid iii, citrus viroid iv, and citrus viroid os ... | 2002 | 18943029 |
| interactions between citrus viroids affect symptom expression and field performance of clementine trees grafted on trifoliate orange. | abstract citrus exocortis viroid (cevd), citrus bent leaf viroid (cblvd), a noncachexia variant of hop stunt viroid (hsvd), citrus viroid iii (cvd-iii), and citrus viroid iv (cvd-iv) were co-inoculated as two-, three-, four-, and five-viroid mixtures to clementine trees grafted on trifoliate orange to evaluate their effect on symptom expression, tree growth, and fruit yield. most trees infected with cevd-containing viroid mixtures developed exocortis scaling symptoms, as did cevd alone, whereas ... | 2006 | 18943417 |
| host effect on the molecular and biological properties of a citrus exocortis viroid isolate from vicia faba. | abstract citrus exocortis viroid (cevd) is the casual agent of citrus exocortis disease, and has been found in naturally infected citrus and noncitrus hosts. field isolates of cevd may infect susceptible hosts as a complex of genetically related sequence variants (haplotypes). in the present work, a cevd isolate recovered from a symptomless broad bean plant was characterized as a heterogeneous population with a nucleotide diversity of 0.026, which did not contain a predominant haplotype. when nu ... | 2007 | 18943641 |
| two nucleotide positions in the citrus exocortis viroid rna associated with symptom expression in etrog citron but not in experimental herbaceous hosts. | citrus exocortis viroid (cevd) is the causal agent of exocortis disease of citrus. cevd has a wide host range that includes woody and herbaceous species. a new cevd strain (cevd(col)), phylogenetically clustering with cevd variants of class a inducing severe symptoms in tomato, was identified in colombia and shown to induce only extremely mild symptoms in etrog citron indicator plants. using site-directed mutagenesis, two nucleotide substitutions (314a → g and 315u → a) in the lower strand of th ... | 2010 | 21199569 |
| in vivo generated citrus exocortis viroid progeny variants display a range of phenotypes with altered levels of replication, systemic accumulation and pathogenicity. | citrus exocortis viroid (cevd) exists as populations of heterogeneous variants in infected hosts. in vivo generated cevd progeny variants (cevd-pvs) populations from citrus protoplasts, seedlings and mature plants, following inoculation with transcripts of a single cevd cdna-clone (wild-type, wt), were studied. the cevd-pvs population in protoplasts was heterogeneous and became progressively more homogeneous in seedlings and mature plants. the infectivity and pathogenicity of selected cevd-pvs w ... | 2011 | 21782204 |
| development and validation of a multiplex rt-pcr method for the simultaneous detection of five grapevine viroids. | grapevine yellow speckle viroid 1 (gysvd-1), grapevine yellow speckle viroid 2 (gysvd-2), australian grapevine viroid (agvd), hop stunt viroid (hsvd) and citrus exocortis viroid (cevd) are the five viroids known to infect naturally grapevines. we developed a multiplex rt-pcr (mrt-pcr) method for the simultaneous detection of these five viroids and the amplification of the cdna fragment of a host-derived mrna (actin mrna) as an internal positive control. specific primers for each targeted viroid ... | 2012 | 22004912 |
| 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 |
| comprehensive diversity analysis of viroids infecting grapevine in china and japan. | to date, several viroid species have been shown to infect grapevine, including hop stunt viroid (hpsvd), citrus exocortis viroid (cevd), australian grapevine viroid (agvd), grapevine yellow speckle viroid-1 (gysvd-1), grapevine yellow speckle viroid-2 (gysvd-2) and a tentative new species, grapevine yellow speckle viroid-3 (gysvd-3). here, we identified and analyzed the distribution, genetic diversity, and molecular properties of viroids infecting grapevine cultivated in china and japan, includi ... | 2012 | 22940569 |
| processing of nuclear viroids in vivo: an interplay between rna conformations. | replication of viroids, small non-protein-coding plant pathogenic rnas, entails reiterative transcription of their incoming single-stranded circular genomes, to which the (+) polarity is arbitrarily assigned, cleavage of the oligomeric strands of one or both polarities to unit-length, and ligation to circular rnas. while cleavage in chloroplastic viroids (family avsunviroidae) is mediated by hammerhead ribozymes, where and how cleavage of oligomeric (+) rnas of nuclear viroids (family pospiviroi ... | 2007 | 18052530 |
| 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 |
| one-step multiplex rt-qpcr detects three citrus viroids from different genera in a wide range of hosts. | a one-step multiplex reverse transcription real-time quantitative polymerase chain reaction (rt-qpcr) based on species-specific minor groove binding (mgb) probes, was developed for the simultaneous detection, identification, and quantification of three citrus viroids belonging to different genera. citrus exocortis viroid (pospiviroid), hop stunt viroid (hostuviroid), and citrus bark cracking viroid (cocadviroid) cause a variety of maladies in agriculturally significant crops. therefore, reliable ... | 2017 | 28300606 |
| phloem restriction of viroids in three citrus hosts is overcome by grafting with etrog citron: potential involvement of a translocatable factor. | viroid systemic spread involves cell-to-cell movement from initially infected cells via plasmodesmata, long-distance movement within the phloem and again cell-to-cell movement to invade distal tissues including the mesophyll. citrus exocortis viroid (cevd), hop stunt viroid, citrus bent leaf viroid, citrus dwarfing viroid, citrus bark cracking viroid and citrus viroid v remained phloem restricted when singly infecting citrus karna, citrus aurantium and poncirus trifoliata, but not etrog citron, ... | 2015 | 25888624 |
| a mutual titer-enhancing relationship and similar localization patterns between citrus exocortis viroid and hop stunt viroid co-infecting two citrus cultivars. | citrus exocortis viroid (cevd) and hop stunt viroid (hsvd) are commonly found simultaneously infecting different citrus cultivars in taiwan. a crucial question to be addressed is how accumulations of these two viroids affect each other in an infected plant. in this study, we investigated the relationship between the two viroids at macroscopic and microscopic levels. | 2015 | 26377407 |
| multiplex detection, distribution, and genetic diversity of hop stunt viroid and citrus exocortis viroid infecting citrus in taiwan. | two citrus viroids, citrus exocortis viroid (cevd) and hop stunt viroid (hsvd), have been reported and become potential threats to the citrus industry in taiwan. the distributions and infection rates of two viroids have not been investigated since the two diseases were presented decades ago. the genetic diversities and evolutionary relationships of two viroids also remain unclear in the mix citrus planted region. | 2015 | 25645458 |
| 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 |
| characterization of viroid-like rnas associated with the citrus exocortis syndrome. | three additional viroid-like rna species (rna-i, -ii, and -iii), smaller than the 371-nucleotide citrus exocortis viroid (cev), have been identified in citron (citrus medica) trees which display symptoms of the exocortis disease. the three rnas migrate on polyacrylamide gels under denaturing conditions in the region between cev and avocado sunblotch viroid circular molecules, indicating a size range of about 311-335 nucleotide residues in both circular and linear molecular forms. rna-ii is remov ... | 1986 | 18640615 |
| monomeric linear rna of citrus exocortis viroid resulting from processing in vivo has 5'-phosphomonoester and 3'-hydroxyl termini: implications for the rnase and rna ligase involved in replication. | members of the family pospiviroidae, like citrus exocortis viroid (cevd), replicate through an rna-based asymmetric rolling-circle mechanism in which oligomeric plus-strand [(+)] rna intermediates are cleaved to monomeric linear (ml) rna and then circularized. here we show, by rapid amplification of 5' and 3' cdna ends and in vitro ligation assays, that ml cevd (+) rna resulting from cleavage of a dimeric transcript transgenically expressed in arabidopsis thaliana contains 5'-phosphomonoester an ... | 2008 | 18701598 |
| comparison of multimeric plus and minus forms of viroids and virusoids. | in order to investigate the mechanism of replication of viroids and virusoids, we have compared the replication intermediates of three members of each group in nucleic acid extracts of infected plants. viroids were avocado sunblotch viroid (asbv), citrus exocortis viroid (cev) and coconut cadang cadang viroid (cccv). virusoids were from velvet tobacco mottle virus (vtmov), solanum nodiflorum mottle virus (snmv) and lucerne transient streak virus (ltsv). analysis of intermediates was by the north ... | 1985 | 24310879 |
| diagnostic real-time rt-pcr for the simultaneous detection of citrus exocortis viroid and hop stunt viroid. | citrus exocortis viroid (cevd) and hop stunt viroid (hsvd) are two important viroids known to infect several plant species worldwide. in this study, a real-time reverse transcription (rt) taqman polymerase chain reaction (pcr) assay was developed and optimized for the simultaneous detection of cevd and hsvd. the assay's analytical and diagnostic sensitivity and specificity were evaluated using reference isolates. two different rna extraction methods and one rapid crude template preparation proce ... | 2014 | 24252553 |
| validation of high-throughput real time polymerase chain reaction assays for simultaneous detection of invasive citrus pathogens. | a number of important citrus pathogens are spread by graft propagation, arthropod vector transmission and inadvertent import and dissemination of infected plants. for these reasons, citrus disease management and clean stock programs require pathogen detection systems which are economical and sensitive to maintain a healthy industry. to this end, multiplex quantitative real-time pcr (qpcr) assays were developed allowing high-throughput and simultaneous detection of some major invasive citrus path ... | 2013 | 23891873 |
| a leafhopper-transmissible dna virus with novel evolutionary lineage in the family geminiviridae implicated in grapevine redleaf disease by next-generation sequencing. | a graft-transmissible disease displaying red veins, red blotches and total reddening of leaves in red-berried wine grape (vitis vinifera l.) cultivars was observed in commercial vineyards. next-generation sequencing technology was used to identify etiological agent(s) associated with this emerging disease, designated as grapevine redleaf disease (grd). high quality rna extracted from leaves of grape cultivars merlot and cabernet franc with and without grd symptoms was used to prepare cdna librar ... | 2013 | 23755117 |
| a noncoding plant pathogen provokes both transcriptional and posttranscriptional alterations in tomato. | viroids are single-stranded, circular, noncoding rnas that infect plants, causing devastating diseases. in this work, we employed 2d dige, followed by ms identification, to analyze the response of tomato plants infected by citrus exocortis viroid (cevd). among the differentially expressed proteins detected, 45 were successfully identified and classified into different functional categories. validation results by rt-pcr allowed us to classify the proteins into two expression groups. first group i ... | 2013 | 23303650 |
| microarray analysis of etrog citron (citrus medica l.) reveals changes in chloroplast, cell wall, peroxidase and symporter activities in response to viroid infection. | viroids are small (246-401 nucleotides), single-stranded, circular rna molecules that infect several crop plants and can cause diseases of economic importance. citrus are the hosts in which the largest number of viroids have been identified. citrus exocortis viroid (cevd), the causal agent of citrus exocortis disease, induces considerable losses in citrus crops. changes in the gene expression profile during the early (pre-symptomatic) and late (post-symptomatic) stages of etrog citron infected w ... | 2012 | 22420919 |