| a viroid from nematanthus wettsteinii plants closely related to the columnea latent viroid. | a viroid was isolated from symptomless nematanthus wettsteinii plants using the return-page method for analysis of low m(r) nucleic acids. the rna was transmitted to tomato, three cultivars of potato, and scopolia sinensis plants by mechanical inoculation or by grafting. infected solanaceous plants developed symptoms similar to those caused by potato spindle tuber viroid (pstvd). the nematanthus viroid consists of 372 nucleotides, 214 g+c, 158 a+u, with a g+c/a+u ratio of 1.35. one of seven cdna ... | 1992 | 1279098 |
| identification of a new viroid as the putative causal agent of pear blister canker disease. | a small rna species with the structural and functional properties characteristic of viroids has been isolated from three different pear sources each of which induced symptoms of the pear blister canker (pbc) disease when indexed in the pear indicator a 20. a close association between this rna and pbc disease was established, since two of the three studied sources were known to be affected by this malady only, and the viroid was not detected in healthy pear tissue. moreover, the pbc-associated vi ... | 1991 | 2045786 |
| 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 |
| a novel aspect of the information content of viroids. | viroids were found to exhibit a structural periodicity characterized by repeat units of a length of 11 or 12 (potato spindle tuber viroid group and coconut cadang-cadang viroid), 60 (apple scar skin viroid) and 80 (avocado sunblotch viroid) nucleotide residues, respectively. it is suggested that structural periodicity of viroids is an indication of their protein-binding ability. | 1988 | 3167064 |
| grapevine yellow speckle viroid: structural features of a new viroid group. | a single stranded circular rna was isolated from grapevines infected with yellow speckle disease. the rna which we have called grapevine yellow speckle viroid (gysv), contains 367 nucleotide residues and has the potential to form the rod-like secondary structure characteristic of viroids. gysv has 37% sequence homology with the recently described apple scar skin viroid (assv; 330 residues) and has some sequence homology with the viroids in the potato spindle tuber viroid (pstv) group. the sequen ... | 1988 | 3344221 |
| nucleotide sequence and secondary structure of apple scar skin viroid. | the complete nucleotide sequence of apple scar skin viroid(assv) has been established, and a probable secondary structure is proposed. a single-stranded circular assv rna consists of 330 nucleotides and can assume the rodlike conformation with extensive base-pairing characteristic of all the known viroids. assv shows low sequence homologies with other viroids and lacks the central conserved region. these indicate that assv should be allocated to a separate viroid group. however, homologous seque ... | 1987 | 3658673 |
| identification and molecular properties of a 306 nucleotide viroid associated with apple dimple fruit disease. | a new viroid associated with an apple fruit disorder similar to, but more severe than, the dapple apple disease induced in some varieties by apple scar skin viroid (assvd) has been found. the new viroid, tentatively termed apple dimple fruit viroid (adfvd), is a circular rna of 306 nucleotides which adopts a quasi-rod-like conformation of minimum free energy. it contains the core nucleotides of the central conserved region (ccr) of the assvd group as well as the terminal conserved region (tcr) p ... | 1996 | 8922478 |
| sensitive detection of potato spindle tuber and temperate fruit tree viroids by reverse transcription-polymerase chain reaction-probe capture hybridization. | a rapid and sensitive assay for the specific detection of plant viroids using reverse transcription-polymerase chain reaction (rt-pcr) -probe capture hybridization (rt-pcr-enzyme-linked immunosorbent assay (elisa)) was developed. the assay was applied successfully for the detection of potato spindle tuber viroid, peach latent mosaic viroid, or apple scar skin viroid from viroid infected leaf tissue. clarified sap extract from infected leaf tissue was treated first with genereleaser polymeric mat ... | 1999 | 10471024 |
| 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 |
| 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 |
| use of dried high-phenolic laden host leaves for virus and viroid preservation and detection by pcr methods. | the efficiency of rna extraction for apricot latent virus (aplv), plum bark necrosis stem pitting associated virus (pbnspav), prunus necrotic ring spot virus (pnrsv), potato virus y (pvy), and apple scar skin viroid (assvd) from infected hosts is of great importance for molecular diagnosis by the polymerase chain reaction (pcr). a method is described for drying tissue to overcome phenolic inhibitors of viral rna. this study showed that the infected host leaves, dried at 65 degrees c for 2 days a ... | 2006 | 16879877 |
| determination of major viral and sub viral pathogens incidence in apple orchards in himachal pradesh. | apple is the major commercial horticulture crop in himachal pradesh and other hill states of jammu & kashmir, uttarakhand and some parts of northeastern states of india. in order to gather data on health status and incidence of virus and virus-like pathogens in apple orchards, survey was conducted in the month of june and september, 2010 in hatkoti, rohru, kuthara, jubbal and khadapathar areas of major apple producing shimla district of himachal pradesh. a total of 250 samples were collected and ... | 2011 | 23730008 |
| a multiple rt-pcr assay for simultaneous detection and differentiation of latent viruses and apscarviroids in apple trees. | apple chlorotic leaf spot virus (aclsv), apple stem grooving virus (asgv), and apple stem pitting virus (aspv) are three latent viruses frequently occurring in apple trees worldwide. in field orchards, these viruses are frequently found in a mixed infection with viroids in the genus apscarviroid, including apple scar skin viroid, and apple dimple fruit viroid. together these viruses and viroids could cause serious damage to apple fruit production worldwide. rapid and efficient detection methods ... | 2016 | 27054889 |
| simultaneous detection of major pome fruit viruses and a viroid. | a rapid and sensitive two-step rt-pcr protocol for simultaneous detection of major apple viruses, namely apple mosaic virus (apmv), apple stem pitting virus (aspv), apple stem grooving virus (asgv), apple chlorotic leaf spot virus (aclsv) and apple scar skin viroid (assvd), was developed. five specific primer pairs were tested and confirmed for these viruses and viroid together in a single tube, giving amplicons of ~198, ~330, ~370, ~547 and ~645 bp corresponding to asgv, assvd, aspv, apmv and a ... | 2014 | 25320423 |
| apple scar skin viroid naked rna is actively transmitted by the whitefly trialeurodes vaporariorum. | nucleic acid transfer between plants is a phenomenon which is likely to occur in many ways in nature. we report here the active transmission of apple scar skin viroid (assvd) naked ssrna species by the whitefly trialeurodes vaporariorum (tv). not only the viroid rna, its dna form was also identified from the insect. the viroid transfer efficiency was enhanced with the help of cucumis sativus phloem protein 2 (cspp2), a plant protein known to translocate viroid rnas. this pp2/assvd complex is sta ... | 2015 | 26327493 |
| development of a duplex one-step rt-qpcr assay for the simultaneous detection of apple scar skin viroid and plant rna internal control. | apple scar skin viroid (assvd) is an important quarantine pathogen for international movement of pome germplasm as it can cause significant damage to pip fruit. a one-step real-time rt-pcr assay was developed for the rapid and sensitive detection of assvd. the assay was able to detect a wide range of assvd isolates and was highly specific compared to a published conventional rt-pcr. the detection limit of the new assay was estimated to be about 100 copies of the assvd target. the assay can be ru ... | 2015 | 25962536 |
| one-step multiplex quantitative rt-pcr for the simultaneous detection of viroids and phytoplasmas of pome fruit trees. | a one-step multiplex real-time quantitative reverse transcription polymerase chain reaction (rt-qpcr) based on taqman chemistry was developed for the simultaneous detection of pear blister canker viroid and apple scar skin viroid along with universal detection of phytoplasmas, in pome trees. total nucleic acids (tnas) extraction was performed according to a modified ctab protocol. primers and taqman mgb probes for specific detection of the two viroids were designed in this study, whereas for phy ... | 2015 | 25479356 |
| 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 |
| the termini of a new citrus viroid contain duplications of the central conserved regions from two viroid groups. | a citrus viroid associated with dwarfing, cvdiiia, has been sequenced and its 294 nucleotide residues can be arranged to form the typical rod-like secondary structure of other viroids with 71% of nucleotides base-paired. cvdiiia has greatest sequence similarity with apple scar skin viroid (assvd; 69%) and has the central sequence which is conserved in the assvd group. cvdiiia is the smallest member of the assvd group but contains the terminal conserved region shared by all viroids over 300 nucle ... | 1995 | 7828732 |
| nucleotide sequence and structural features of the group iii citrus viroids. | the nucleotide sequence and secondary structure of two representative variants from the group iii citrus viroids. cvd-iiia (297 bases) and cvd-iiib (294 bases) were determined. the variants are related to the apple scar skin viroid (assvd) family. although smaller in size than any of the assvd-related viroids, the central conserved region as well as most of the terminal conserved region of assvd is retained. the rod-like structural configuration (characteristic of assvd) of the variants as predi ... | 1994 | 7996150 |
| scar skin and dapple apple viroids are seed-borne and persistent in infected apple trees. | the closely related apple scar skin viroid (assv) and dapple apple viroid (dav) were identified in whole seeds from infected pome fruits by hybridization of extracted nucleic acids with a 32p-labelled assv crna probe. viroid amounts were greater in seed coats and subcoats than in seed cotyledons and embryos. assv or dav was also detected in nucleic acid extracts from infected seeds, cotyledons and embryos by reverse transcription/polymerase chain reaction with viroid-cdna-specific primers follow ... | 2006 | 1796215 |
| nucleotide sequence and secondary structure of apple scar skin viroid (assvd) from china. | | 1990 | 1715209 |
| australian grapevine viroid--evidence for extensive recombination between viroids. | australian grapevine viroid (agv, 369 residues) is a novel viroid with less than 50% sequence similarity with any known viroid. nevertheless its entire sequence can be divided into regions, each with a high sequence similarity with segments from one of citrus exocortis, potato spindle tuber, apple scar skin, and grapevine yellow speckle viroids. agv contains the entire central conserved region of the apple scar skin viroid group and is proposed as a member of this group. agv appears to have orig ... | 1990 | 2336357 |
| grapevine viroid 1b, a new member of the apple scar skin viroid group contains the left terminal region of tomato planta macho viroid. | gv1b is one of five viroids that have recently been purified from grapevines. gv1b has now been sequenced and its 363 nucleotide residues can potentially form the typical rod-like structure of viroids with 67% of nucleotides base-paired. gv1b has highest sequence similarity with grapevine yellow speckle viroid (gysv; 73%) and has a central sequence which is conserved in gysv and apple scar skin viroid (assv) which have been reported to constitute the assv group. therefore, we have placed gv1b in ... | 1989 | 2728350 |