Molecular Plant-Microbe Interactions (2009) 22, 1250-1257

Afshin Hassani-Mehraban, A.B. Brenkman, N.J.F. van den Broek, Rob Goldbach and Richard Kormelink (2009)
RNAi-Mediated transgenic tospovirus resistance broken by intraspecies silencing suppressor protein complementation
Molecular Plant-Microbe Interactions 22 (10), 1250-1257
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 (NS_s) gene also allowed TYRV-t to break the resistance. This phenomenon was also observed when the homologous (TYRV-t) NS_s gene was provided from a PVX replicon, demonstrating that TYRV can break RNA-mediated host resistance upon a priori expression of its NS_s 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 NS_s-though based on suppressing RNA silencing-is species-dependent.
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Link to article at publishers website
Database assignments for author(s): Afshin Hassani-Mehraban

Research topic(s) for pests/diseases/weeds:
molecular biology - genes
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Orthotospovirus tomatanuli	Tomato (Solanum lycopersicum)