ARS | Publication request: A Virus-Induced Gene Silencing System for the Analysis of Disease Resistance Pathways in Wheat and Barley

Submitted to: International Fusarium Workshop
Publication Type: Abstract
Publication Acceptance Date: November 5, 2005
Publication Date: N/A

Technical Abstract: Systems for virus-induced gene silencing (VIGS) that can rapidly and efficiently create gene knockout phenotypes, have proven to be very useful tools for the analysis of plant gene function. VIGS is a form of RNA-mediated gene silencing. All forms of RNA-mediated gene silencing involve the production of large amounts of dsRNA that activates a host defense mechanism that results in the degradation of all RNAs with homology to the sequences within the dsRNA. In VIGS, certain RNA viruses are used to produce dsRNAs that trigger the silencing mechanism. If the virus has been engineered to contain sequences from a plant gene of interest, mRNAs from that gene are degraded as well, thus creating knockout phenotype for the chosen gene. Given a validated VIGS system and a 200-500bp fragment from a gene of interest as starting material, it is possible to assemble the VIGS construct, infect plants and observe the knockout phenotype within one month. The first VIGS systems were effective in only a few dicot species however, recently a VIGS system based on Barley stripe mosaic virus has been demonstrated to efficiently trigger VIGS in barley and wheat. The creation of gene knockouts in polyploid plants, such as wheat, is very difficult using conventional mutagenesis strategies because expression of homeoloci mask mutations. However, since VIGS operates through a homology-dependent mechanism, it promises to be particularly useful in polyploids, because mRNAs from homeoloci should be degraded as well, provided they share sufficient sequence homology. This talk will describe the development of the BSMV-VIGS system and demonstrate its utility in the functional analysis of genes required in a range of wheat and barley disease resistance pathways.