RNAi-mediated transgenic tospovirus resistance broken by intraspecies NSs complementation

A. Hassani-Mehraban, A.B. Brenkman, N.F.J. Broek, R.W. Goldbach, R.J.M. Kormelink

Research output: Contribution to journalArticleAcademicpeer-review

18 Citations (Scopus)

Abstract

Extension of an inverted repeat transgene cassette, containing partial nucleoprotein (N) gene sequences from four different tomato-infecting Tospovirus spp. with a partial N gene sequence from the tomato strain of Tomato yellow ring virus (TYRV-t), renders transgenic Nicotiana benthamiana plants additionally resistant to this strain but not to the soybean strain of this Tospovirus sp. (TYRV-s), both strains exhibiting 14.4% nucleotide sequence divergence in their N genes. Surprisingly, coinoculation of the TYRV-t-resistant transgenic lines with both TYRV-t and TYRV-s resulted in rescue of the former. Mass-spectrometric analysis of the viral ribonucleocapsids accumulating in the transgenic plants showed the presence of the N proteins of both strains excluding hetero-encapsidation as rescue mechanism and indicating suppression of TYRV-t N gene transcript breakdown by RNA interference. Prior (Potato virus X [PVX]-vector-mediated) expression of the TYRV-s silencing suppressor (NSs) gene also allowed TYRV-t to break the resistance. This phenomenon was also observed when the homologous (TYRV-t) NSs gene was provided from a PVX replicon, demonstrating that TYRV can break RNA-mediated host resistance upon a priori expression of its NSs protein. Remarkably, mixed inoculation of TYRV-t with other Tospovirus spp. or nonrelated viruses did not result in resistance breaking, indicating that the rescuing activity of NSs—though based on suppressing RNA silencing—is species-dependent.
Original languageEnglish
Pages (from-to)1250-1257
JournalMolecular Plant-Microbe Interactions
Volume22
Issue number10
DOIs
Publication statusPublished - 2009

Keywords

  • spotted-wilt-virus
  • nsm gene-sequences
  • tobacco plants
  • nucleoprotein gene
  • expression
  • constructs
  • antibodies
  • vectors
  • length

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