We have developed an in vitro transcriptional assay using Escherichia coli RNA polymerase to initiate the replication of peach latent mosaic viroid (PLMVd). Regardless of the polarity of the PLMVd strand used as template, initiation in vitro occurred at the same hairpin structure. These initiation sites correspond to the 5′-ends of two small (280 nt) PLMVd-related RNAs found in infected peach l...

We sequenced 34 new peach latent mosaic viroid (PLMVd) variants isolated from nine different peach cultivars. This study provides the widest view of PLMVd diversity reported to date and includes the original characterization of North American variants, which cannot be differentiated from European sequences. PLMVd appears as a species in which each isolate is a complex mixture of RNAs. Analysis ...

The peach latent mosaic viroid (PLMVd) is used to study the interactions between a viroid containing hammerhead ribozymes and its natural host, peach. To gain insight into the molecular basis of the phenotypic effects observed upon viroid infection, sequence variants from three PLMVd isolates that differ in symptom expression on the peach indicator GF-305 have been characterized. Analysis of th...

Peach latent mosaic viroid (PLMVd) is a member of the genus Pelamoviroid in the family Avsunviroidae and infects peach trees. We de novo assembled a PLMVd genome from a peach transcriptome and identified 18 variants in a single peach cultivar, after sequencing 20 PLMVd genomes by Sanger sequencing.

Natural populations of peach latent mosaic viroid (PLMVd) are complex mixtures of variants. During routine testing, TaqMan rtRT-PCR and RNA gel-blot hybridization produced discordant results with some PLMVd isolates. Analysis of the corresponding populations showed that they were exclusively composed of variants (of class II) with a structural domain different from that of the reference and man...

The transcription initiation sites of viroid RNAs, despite their relevance for replication and in vivo folding, are poorly characterized. Here we have examined this question for Peach latent mosaic viroid (PLMVd), which belongs to the family of chloroplastic viroids with hammerhead ribozymes (Avsunviroidae), by adapting an RNA ligase-mediated rapid amplification of cDNA ends methodology develop...

We have investigated the secondary structure of peach latent mosaic viroid (PLMVd) in solution, and we present here the first description of the structure of a branched viroid in solution. Different PLMVd transcripts of plus polarity were produced by using the circularly permuted RNA method and the exploitation of RNA internal secondary structure to position the 5' and 3' termini and studied by...

We characterized the peach latent mosaic viroid (PLMVd) replication intermediates that accumulate in infected peach leaves and determined the tissue and subcellular localization of the RNA species. Using in situ hybridization, we showed that PLMVd strands of both plus and minus polarities concentrate in the cells forming the palisade parenchyma. At the cellular level, PLMVd was found to accumul...

Nucleotide sequences of a broad range of Peach Latent Mosaic Viroid (PLMVd) variants were determined. The variants were isolated from peach, pear, and almond tree samples collected in Tunisia. Sequence analysis confirmed the high variability of PLMVd, as no less than 119 new variants were identified. Variations included new polymorphic positions, insertions of 11 to 14 nucleotides, and new muta...

Northern-blot hybridization and low-scale sequencing have revealed that plants infected by viroids, non-protein-coding RNA replicons, accumulate 21-24 nt viroid-derived small RNAs (vd-sRNAs) similar to the small interfering RNAs, the hallmarks of RNA silencing. These results strongly support that viroids are elicitors and targets of the RNA silencing machinery of their hosts. Low-scale sequenci...