Parasitic weeds are among the most destructive and difficult-to-control of all weeds and cause important crop losses across Europe and neighbouring regions. The intimate connection establishes by the parasite with the host vascular tissues makes unsuccessful the selective control of the parasite. Our ability to understand the complexities of this parasitic plant-host interaction is limited by a lack of knowledge about the parasite itself, especially with respect to parasite genomics. This proposal describes a research plan for Dr. Mónica Fernández-Aparicio to work in the laboratory of Dr. James Westwood at Virginia Tech, USA, with the aim of advancing our understanding of parasitic plants by capitalizing on the emerging discipline of plant genomics. Sequenced genes of weedy parasite species have simply not been available, hampering molecular/genomics research. This situation will change with the data emerging from the current Parasitic Plant Genomic Project which is carrying out in the host group. The candidate will be the first to take advantage of this new knowledge resource. The overall objective of research is to increase understanding of the molecular biology of Orobanche in order to generate new approaches to their control. This research will contribute to a revolution in studies of parasitic weed biology and control. Parasite genes will be targeted for post-transcriptional gene silencing by transmitting a silencing signals from the model host Arabidopsis, to its parasite O. aegyptiaca. For the first time, it will be possible to knock out expression of parasite genes to determine its function. In the knowledge gained by the applicant during the outgoing work will be applied in her returns by adapting genomic approach to a real problematic system in Europe legume-O. crenata and sunflower-O. cumana. The identification of common defence mechanisms in these two pathosystems will be the goal for the returning year.