De novo methylation and co-suppression induced by a cytoplasmically replicating plant RNA virus

EMBO J. 1998 Nov 2;17(21):6385-93. doi: 10.1093/emboj/17.21.6385.


The relationship between co-suppression and DNA methylation was explored in transgenic plants showing inducible co-suppression following infection with a cytoplasmically replicating RNA virus. Induction resulted in a loss of transgene mRNA and resistance to further infection, factors typical of post-transcriptional gene silencing. In infected plants, de novo methylation of the transgene appeared to precede the onset of resistance and only occurred in plants where the outcome was co-suppression. The methylation was limited to sequences homologous to the viral RNA and occurred at both symmetric and non-symmetric sites on the DNA. Although methylation is predicted to occur in mitotic cells, the virus was found not to access the meristem. A diffusible sequence-specific signal may account for the epigenetic changes in those tissues.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • DNA Methylation*
  • Gene Expression Regulation, Plant / genetics
  • In Situ Hybridization
  • Meristem / genetics
  • Mosaic Viruses / genetics
  • Peas
  • Plant Viruses / genetics*
  • Plants, Genetically Modified
  • RNA Viruses / genetics*
  • RNA, Messenger / genetics
  • RNA, Viral / genetics
  • Suppression, Genetic / genetics*
  • Transcription, Genetic / genetics


  • RNA, Messenger
  • RNA, Viral