Encyclopedia of Astrobiology

2015 Edition
| Editors: Muriel Gargaud, William M. Irvine, Ricardo Amils, Henderson James (Jim) CleavesII, Daniele L. Pinti, José Cernicharo Quintanilla, Daniel Rouan, Tilman Spohn, Stéphane Tirard, Michel Viso

Viroid

Reference work entry
First Online:
DOI: https://doi.org/10.1007/978-3-662-44185-5_1630
How to cite

Definition

Viroids are independently replicating circular RNAs of small size (246–401 nucleotides), with compact secondary structure, without protein-coding capacity, and capable of infecting and causing disease in plants. Viroids bear some resemblance with other two replicons: (1) viroid-like satellite RNAs, often called virusoids, which are structurally similar to viroids but dependent on coinfecting helper viruses for replication and transmission, and (2) human hepatitis delta  virus RNA, which is also circular and highly structured, but with a size fourfold larger than that of the largest viroid, coding for a protein in the antigenomic polarity and depending on hepatitis B virus for assembly and transmission.

Overview

Viroids are the minimal RNA replicons characterized so far – their  genome is tenfold smaller than that of the smallest known virus RNA – and, therefore, they can be regarded as the frontier of life (Diener 1972; Gross et al. 1978). Despite being only composed by a...

Keywords

Catalytic RNAs Early replicons Hammerhead ribozymes High mutation rate Small RNAs 
This is a preview of subscription content, log in to check access.

References and Further Reading

  1. Branch AD, Robertson HD (1984) A replication cycle for viroids and other small infectious RNAs. Science 223:450–454CrossRefADSGoogle Scholar
  2. Diener TO (1972) Potato spindle tuber viroid VIII. Correlation of infectivity with a UV-absorbing component and thermal denaturation properties of the RNA. Virology 50:606–609CrossRefGoogle Scholar
  3. Diener TO (1989) Circular RNAs: relics of precellular evolution? Proc Natl Acad Sci U S A 86:9370–9374CrossRefADSGoogle Scholar
  4. Diener TO (2003) Discovering viroids: a personal perspective. Nat Rev Microbiol 1:75–80CrossRefGoogle Scholar
  5. Eigen M, Schuster P (1977) Hypercycle – principle of natural self-organization. A. Emergence of hypercycle. Naturwissenschaften 64:541–565CrossRefADSGoogle Scholar
  6. Flores R, Daròs JA, Hernández C (2000) The Avsunviroidae family: viroids containing hammerhead ribozymes. Adv Virus Res 55:271–323CrossRefGoogle Scholar
  7. Gago S, Elena SF, Flores R, Sanjuán R (2009) Extremely high mutation rate of a hammerhead viroid. Science 323:1308CrossRefADSGoogle Scholar
  8. Gilbert W (1986) The RNA world. Nature 319:618CrossRefADSGoogle Scholar
  9. Gross HJ, Domdey H, Lossow C, Jank P, Raba M, Alberty H, Sänger HL (1978) Nucleotide sequence and secondary structure of potato spindle tuber viroid. Nature 273:203–208CrossRefADSGoogle Scholar
  10. Hutchins C, Rathjen PD, Forster AC, Symons RH (1986) Self-cleavage of plus and minus RNA transcripts of avocado sunblotch viroid. Nucleic Acids Res 14:3627–3640CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  1. 1.Instituto de Biología Molecular y Celular de Plantas (UPV-CSIC)Universidad Politécnica de Valencia – Consejo Superior de Investigaciones CientificasValenciaSpain