Unusual Long-Distance Movement Strategies of Potato mop-top virus RNAs in Nicotiana benthamiana

Lesley Torrance, Nina I. Lukhovitskaya, Mikhail V. Schepetilnikov, Graham H. Cowan, Angelika Ziegler, Eugene I. Savenkov

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)

Abstract

The Potato mop-top virus (PMTV) genome encodes replicase, movement, and capsid proteins on three different RNA species that are encapsidated within tubular rod-shaped particles. Previously, we showed that the protein produced on translational readthrough (RT) of the coat protein (CP) gene, CP-RT, is associated with one extremity of the virus particles, and that the two RNAs encoding replicase and movement proteins can move long distance in the absence of the third RNA (RNA-CP) that encodes the capsid proteins, CP and CP-RT. Here, we examined the roles of the CP and CP-RT proteins on RNA movement using infectious clones carrying mutations in the CP and CP-RT coding domains. The results showed that, in infections established with mutant RNA-CP expressing CP together with truncated CP-RT, systemic movement of the mutant RNA-CP was inhibited but not the movement of the other two RNAs. Furthermore, RNA-CP long-distance movement was inhibited in a mutant clone expressing only CP in the absence of the CP-RT polypeptide. CP-RT was not necessary for particle assembly because virions were observed in leaf extracts infected with the CP-RT deletion mutants. RNA-CP moved long distance when protein expression was suppressed completely or when CP expression was suppressed so that only CP-RT or truncated CP-RT was expressed. CP-RT but not CP interacted with the movement protein TGB1 in the yeast two-hybrid system. CP-RT and TGB1 were detected by enzyme-linked immunosorbent assay in virus particles and the long-distance movement of RNA-CP was correlated with expression of CP-RT that interacted with TGB1; mutant RNA-CP expressing truncated CP-RT proteins that did not interact with TGB1 formed virions but did not move to upper noninoculated leaves. The results indicate that PMTV RNA-CP can move long distance in two distinct forms: either as a viral ribonucleoprotein complex or as particles that are most likely associated with CP-RT and TGB1.

Original languageEnglish
Pages (from-to)381-390
Number of pages10
JournalMolecular Plant-Microbe Interactions
Volume22
Issue number4
DOIs
Publication statusPublished - Apr 2009

Keywords

  • TRIPLE GENE BLOCK
  • PROTEIN-ENCODING RNA
  • STRIPE-MOSAIC-VIRUS
  • COAT PROTEIN
  • GENOME ORGANIZATION
  • READTHROUGH PROTEIN
  • MOLECULAR-BIOLOGY
  • TRAFFICKING
  • SEQUENCE
  • SUPPRESSION

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