Viruses are among the parasites that induce the most severe damages on cultivated plants. Despite the availability of insecticides to control insect vectors and of cultivars that show resistance to specific virus strains, sustained protection of our crops against viruses can only be achieved if approaches are built on a thorough understanding of the molecular mechanisms that determine virus:host compatibility and disease. Viral infection is associated with the altered expression of host genes, many of which are caused by fine-tuned interactions with the host RNA silencing machinery, likely to ultimately facilitate the development of systemic infection. RNA silencing also acts to restrict virus overproduction. Thus, RNA silencing is utilized by both the virus and its host to maintain a subtle equilibrium between virus multiplication and host integrity. It is generally conceived that agricultural crops and plants in natural communities may harbor pathogens, including viruses, as symptom-free carriers and that disease may develop if plants are stressed in a warmer climate. Thus, while normal, coevolved interactions of viruses with the host RNA silencing machinery are optimally balanced such that infection is achieved without causing damage to the host, viruses may cause dangerous outbreaks and disease if this subtle equilibrium between virus multiplication and host integrity is disturbed. Given that RNA silencing responds to temperature, it is of utmost urgency that we begin to understand how changes in climate will affect the regulation and control of viruses within their susceptible hosts. The partners in this project have extensive expertise in the analysis of genome-wide approaches to investigate RNA silencing pathways and especially virus-inducible, small RNA (sRNA)-directed regulatory nodes. Here, with support by an SME, we transfer results/expertise and extent this research to the analysis of virus infection in Rapeseed (Oilseed rape, “Canola”, Brassica napus L), the largest source of vegetable oil in the world. Rapeseed is vulnerable by a number of widespread viruses that require extensive use of toxic insecticides to control them. In this project, we will i) gain insight how virus-inducible sRNA:target regulatory networks contribute to the establishment of virus infection, and/or host defense, and disease in this crop; ii) determine the influences of temperature on the balanced regulation of these networks and derive important information with regard to climate change; iii) identify virus-induced Rapeseed genes, and virus- and Rapeseed-derived sRNAs with their respective Rapeseed gene targets to test their role in virus infection in Rapeseed and thus evaluate their potential for approaches to achieve Rapeseed crop protection; iv) disseminate the results to Rapeseed breeders and other stakeholders involved in Rapeseed production and thus contribute to the development of sustained Rapeseed production.