Our long-term goal is to ensure effective and durable resistance in wheat to Hessian fly. One approach we are taking toward this goal is to test combinations of effective undeployed R genes using F1 plants and Hessian fly collections from different locations across the Southeast. Results will test the hypothesis that deployment of a combination of two highly effective R genes will be more efficacious and potentially more durable than single gene releases. We are also employing an in planta bioassay with Hessian fly larvae to discover toxic proteins that could be utilized in transgenic resistance. Using this assay we are testing lectins for toxicity as well as various Bacillus thuringiensis Cry δ-endotoxins. These results are testing the hypothesis that toxic proteins can provide effective transgenic resistance to Hessian fly that can be pyramided with combinations of native genes for resistance. A third approach to develop novel resistance in wheat to Hessian fly is the application of RNA interference (RNAi). We have used RNAi as a functional genomics tool with Hessian fly larvae and recently developed what appears to be a simple and effective approach to eliciting RNAi knockdown of targeted transcripts. Preliminary results with RNAi suggest we have identified a secreted salivary gland protein (SSGP) that is a virulence effector involved in the stunting of seedling wheat by Hessian fly larvae. When the gene encoding this SSGP is silenced by RNAi larvae appear to be unable to stunt wheat and cannot develop properly. We propose to test the hypothesis that plant mediated RNAi silencing of this gene can provide effective resistance to Hessian fly.
Rich Shukle Ph.D. (Research Entomologist)
Sue Cambron (Support Scientist)
Alisha Johnson (Ph.D. Student)
Jacob Shreve (Masters Student)