| mutational analysis of viroid pathogenicity: tomato apical stunt viroid. | a series of nucleotide substitutions within the pathogenicity domain of tomato apical stunt viroid have been evaluated for their effects upon infectivity and symptom expression. none of the 12 a----g substitutions and one c----u substitution that were examined abolished infectivity in a whole plant bioassay, and the resulting progeny were characterized by nucleotide sequence analysis of cdnas amplified by the polymerase chain reaction. four of the 13 substitutions gave rise to altered progeny, b ... | 1990 | 2131097 |
| the role of the viroid central conserved region in cdna infectivity. | the effect of sequence duplication upon the infectivity of plasmid dnas containing monomeric tomato apical stunt viroid cdnas has been determined. two factors appear to control the specific infectivity of the different plasmid constructions tested: the presence of a subset of a palindromic sequence located within the central conserved region and the orientation of the viroid cdna within the recombinant plasmid. deletions which disrupt the integrity of the putative processing site abolished cdna ... | 1990 | 2309443 |
| 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 |
| infectivity of chimeric viroid transcripts reveals the presence of alternative processing sites in potato spindle tuber viroid. | in an investigation of viroid replication and pathogenesis, we have assessed the effect of sequence duplication of the upper central conserved region (ccr) of the molecule on the infectivity of rnas transcribed in vitro from partial dimers of wild-type and mutant viroid cdnas. in one set of experiments, the relative infectivities of one monomeric potato spindle tuber viroid (pstv) and five oligomeric sp6 transcripts [pstv or pstv-tasv (tomato apical stunt viroid) chimeras] were compared. with on ... | 1989 | 2728347 |
| nucleotide sequence of a full-length infectious clone of the indonesian strain of tomato apical stunt viroid (tasv). | | 1987 | 3697101 |
| a viroid from solanum pseudocapsicum closely related to the tomato apical stunt viroid. | a viroid was isolated from symptomless solanum pseudocapsicum cultivar (cv) 'new patterson' plants using the bidirectional page method for analysis of small circular rna molecules. the viroid was transmitted to tomato by mechanical inoculation. infected tomato plants developed symptoms similar to those caused by potato spindle tuber viroid (pstvd). cloning and sequencing revealed that the viroid from solanum pseudocapsicum is closely related to the tomato apical stunt viroid (tasvd). therefore, ... | 1996 | 8856021 |
| a viroid from brunfelsia undulata closely related to the columnea latent viroid. | a viroid was isolated from symptomless brunfelsia undulata plants using the bidirectional page method for analysis of small circular rna molecules. the viroid was transmitted to tomato by mechanical inoculation. infected tomato plants developed symptoms similar to those caused by intermediate strains of potato spindle tuber viroid (pstvd). cloning and sequencing revealed that the viroid from brunfelsia undulata is closely related to the columnea latent viroid (clvd). therefore, the new viroid se ... | 1996 | 8920818 |
| site-specific mutagenesis of potato spindle tuber viroid cdna: : alterations within premelting region 2 that abolish infectivity. | the infectivity of cloned viroid cdnas permits investigation of structure/function relationships in these unusual pathogenic rnas by systematic site-specific mutagenesis of the cdnas and subsequent bioassay. we have used three different strategies to create nucleotide substitutions within premelting region 2, a region of potato spindle tuber viroid (pstv) believed to be important in viroid replication: sodium bisulfitecatalyzed deamination of deoxycytosine residues, oligonucleotide-directed muta ... | 1986 | 24307277 |
| 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 |
| rna-directed dna methylation efficiency depends on trigger and target sequence identity. | rna-directed dna methylation (rddm) in plants has been extensively studied, but the rna molecules guiding the rddm machinery to their targets are still to be characterized. it is unclear whether these molecules require full complementarity with their target. in this study, we have generated nicotiana tabacum (nt) plants carrying an infectious tomato apical stunt viroid (tasvd) transgene (nt-tasvd) and a non-infectious potato spindle tuber viroid (pstvd) transgene (nt-sb2). the two viroid sequenc ... | 2016 | 27121647 |
| quantitation and localization of pospiviroids in aphids. | in this paper, the potential role of aphids in viroid transmission was explored. apterous aphids were fed on pospiviroid-infected plants and viroid targets in the aphids were consequently quantified through rt-qpcr and localized within the aphid body using fluorescence in situ hybridization (fish). based on the analytical sensitivity test, the limit of detection (lod) was estimated at 1.69×10(6) viroid copies per individual aphid body. to localize the viroids in the aphids, a pospiviroid-generic ... | 2015 | 25455904 |
| characterization of tomato apical stunt viroid isolated from a 24-year old seed lot of capsicum annuum. | tomato apical stunt viroid (tasvd) has been identified in a 24-year old seed lot of capsicum annuum produced in taiwan. it is the first finding of tasvd in this plant species. the isolate could be discriminated from all reported isolates of tasvd based on its nucleotide sequence, which showed only 94.8% identity with the most related genotype of tasvd. this discrimination was substantiated by phylogenetic analysis. inoculation of a rna extract of contaminated seeds to healthy pepper plants showe ... | 2017 | 28204897 |