Sequence analysis by primer-extension at the level of their cDNA showed that the RNA genomes of various field isolates of potato spindle tuber viroid (PSTV) of different virulence differ from each other only in a few nucleotides in two distinct regions of the rod-shaped molecule. Despite insertions and deletions the chain length of 359 nucleotides is strictly conserved in all the isolates studied. Thermodynamic calculations revealed that due to the observed sequence differences the region located at the left hand part of the rod-like secondary structure of the PSTV molecule, denoted 'virulence modulating (VM) region', becomes increasingly unstable with the increasing virulence of the corresponding isolate. Based on these data we propose in molecular terms a model for the mechanism of viroid pathogenicity. It implies that the nucleotides of the VM region specify and modulate the binding- and hence the competition-potential of the PSTV RNA molecule for a still unknown host factor(s) and thus determine the virulence of PSTV.
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http://dx.doi.org/10.1002/j.1460-2075.1985.tb03913.x | DOI Listing |
Mol Plant Pathol
December 2024
Plant Molecular and Cell Biology Program, University of Florida, Gainesville, Florida, USA.
Viroids are single-stranded circular noncoding RNAs that mainly infect crops. Upon infection, nuclear-replicating viroids engage host DNA-dependent RNA polymerase II for RNA-templated transcription, which is facilitated by a host protein TFIIIA-7ZF. The sense-strand and minus-strand RNA intermediates are differentially localised to the nucleolus and nucleoplasm regions, respectively.
View Article and Find Full Text PDFPlant Dis
December 2024
Guangxi University, College of Agriculture, 100 Daxue East Road, Nanning, Guangxi, China, 530004;
Physiol Plant
November 2024
Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC-Universitat Politècnica de València, Valencia, Spain.
Viroids are small, non-coding RNA pathogens known for their ability to cause severe plant diseases. Despite their simple structure, viroids like Potato Spindle Tuber Viroid (PSTVd) can interfere with plant cellular processes, including transcriptional and post-transcriptional mechanisms, impacting plant growth and yield. In this study, we have investigated the role of the Target Of Rapamycin (TOR) signaling pathway in modulating viroid pathogenesis in tomato plants infected with PSTVd.
View Article and Find Full Text PDFVirusdisease
September 2024
Yokohama Plant Protection Station, Ministry of Agriculture, Forestry and Fisheries (MAFF), 1-16-10 Shinyamashita, Naka-Ku, Yokohama, Kanagawa 231-0801 Japan.
Unlabelled: The potato spindle tuber viroid (PSTVd) was discovered to infect Japanese dahlia ( sp.) in 2009. Although the plants were asymptomatic, a comprehensive survey using RT-PCR and RT-qPCR revealed PSTVd occurrence areas spread across 15 out of 24 prefectures where the potentially PSTVd-infected seedlings were supplied.
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