|SHOUP RUPP, JESSICA - Kansas State University|
|CRUZ, LUISA - Kansas State University|
|TRICK, HAROLD - Kansas State University|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/22/2016
Publication Date: 4/22/2016
Publication URL: http://handle.nal.usda.gov/10113/5491330
Citation: Shoup Rupp, J.L., Cruz, L.F., Trick, H.N., Fellers, J.P. 2016. RNAi mediated, stable resistance to Triticum mosaic virus in wheat. Crop Science. 56(4):1602-1610.
Interpretive Summary: In wheat, Triticum mosaic virus (TriMV) causes mosaic symptoms in the leaves, causes the plants to be stunted, and can cause significant reductions in yield. There are no commercial cultivars with resistance to TriMV, so novel sources of resistance are needed. In this work, a fragment of the TriMV coat protein sequence was added to the wheat genome. The sequence was designed in such a way that caused the plant to deactivate the virus RNA using a strategy called RNA interference. Plants were found to maintain resistance for at least six generations. Further testing is needed before this type of resistance can be used in commercial wheat cultivars, but this work shows that the method has great promise for controlling wheat virus diseases.
Technical Abstract: Triticum mosaic virus (TriMV), discovered in 2006, affects wheat production systems in the Great Plains of the United States. There are no available TriMV resistant commercial varieties. RNA interference (RNAi) was evaluated as an alternative strategy to generate resistance to TriMV. An RNAi pANDA-mini-based hairpin expression vector was created from 272 bp the TriMV coat protein sequence. Immature embryos of the wheat cultivar ‘Bobwhite’ were co-transformed by biolistic particle delivery system with the pANDA::TriMVCP vector and pAHC20, containing the bar gene for glufosinate selection. T0 plants were analyzed by PCR for the presence of the RNAi TriMV CP fragment. Transgenic T1 lines were tested for transgene expression via reverse transcription PCR. Virus resistance was evaluated by mechanical inoculation with TriMV and DAS-ELISA. In the T1 generation, resistance was seen in up to 80% of the plants evaluated for the TriMV CP construct. Resistance lines underwent single plant selection to the T6 generation. T6 lines had a high level of resistance when challenged with the virus. To test if the transgene would behave similarly in an adapted variety, crosses were made with the virus susceptible winter wheat, ‘Overley.’ Real-time PCR results indicate a decrease in viral titer up to 20-fold in the T6 transgenic lines, the F1 crosses, and the BC1F1 lines when compared to control plants, providing evidence that this RNAi silencing construct can provide stable resistance to TriMV and has great potential benefits to both breeders and producers.