Location: Hard Winter Wheat Genetics ResearchTitle: RNAi mediated silencing of endogenous wheat genes eIF(iso)4E-2 and eIF4G induce resistance to multiple RNA viruses in transgenic wheat
|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: 3/21/2019
Publication Date: N/A
Interpretive Summary: Wheat viruses are important constraints on wheat yields in the Great Plains of North America. Unfortunately, plant breeders have few genetic sources of resistance to viruses in wheat. In this work, we used a technique called RNAi to down-regulate two wheat proteins called eukaryotic initiation factors (eIF), which are required by many viruses for reproduction. Seven wheat lines were produced with lowered levels of eIF and tested for resistance. Each line was resistant to Wheat streak mosaic virus, Triticum mosaic virus, Soil-borne wheat mosaic virus, and partially resistant to Barley yellow dwarf virus. The broad spectrum virus resistance exhibited by these lines could be very useful to plant breeders.
Technical Abstract: Wheat is lacking sources of effective virus resistance to the potyviruses, Wheat streak mosaic virus (WSMV) and Triticum mosaic virus (TriMV). However, there are numerous plant examples of mutations in eukaryotic initiation factor (eIF) genes providing resistance to various viruses. Potyviruses use host eIFs to facilitate initial translation and further replication of their genomes. Therefore, we hypothesized that silencing TaeIF(iso)4E-2 and TaeIF4G could provide effective and broad spectrum virus resistance. Three transgenic wheat lines with an RNAi hairpin construct targeting eIF(iso)4E-2 and four lines with a hairpin construct targeting eIF4G were recovered through wheat transformation. Early generation lines were found to be resistant to both WSMV and TriMV both separately and during co-inoculation. The lines were selfed to the T5 generation, as well as, crossed onto the hard red winter wheat cultivar 'Karl 92'. Transgenic lines are resistant to WSMV and TriMV, mixed infections of both, resistant to Soil-borne wheat mosaic virus, and demonstrated a significant reduction in Barley yellow dwarf virus antigen. RNAi effectiveness on viral RNA was evaluated using real-time PCR. An 18-fold reduction in WSMV and TriMV viral RNA was found in the T5 transgenic lines when compared to control plants, the F1, and the BC1F1 crosses to Karl 92. This research provides the first evidence that a single transgene can provide resistance to multiple viruses and has great potential benefits to both breeders and producers.