2007 Annual Report 1a.Objectives (from AD-416) Use of RNAi for functional analysis of Hessian fly genes during interactions with wheat. 1b.Approach (from AD-416) Double stranded RNA constructs or DNA constructs expressing RNA forming double stranded structure will be injected into Hessian fly embryos or other stages in development for silencing of target genes. Suppression of the target transcript will be assessed by real-time PCR. Phenotype associated with silencing of a target gene will be revealed by assessing morphological/developmental changes in larvae or changes in the host-plant response to infecting larvae. 3.Progress Report This report serves to document research conducted under a Specific Cooperative Agreement between ARS and Purdue University. Additional details of this research can be found in the report for the parent project 3602-22000-014-00D. Genes involved in the interaction of Hessian fly larvae with wheat have been identified through EST projects by ARS scientists at West Lafayette, IN and Manhattan, KS. BLAST searches have provided putative annotations; however, a large number of novel genes have been revealed. The need exists to test functionality of Hessian fly genes with putative annotation as well as novel genes in the plant/insect interaction. Over the past year we have advanced our use of RNAi to silence genes and the use of real-time PCR to assess knockdown of targeted transcripts. We are now using these expertises to understand the role of specific Hessian fly genes in its interactions with susceptible and resistant plants. Monitoring of activities for this project is achieved through monthly meetings involving the scientists and technical personnel involved. Progress made, modifications in methodology, assessment of genes to be targeted, and manuscripts for publication are discussed at these meetings.