A collaborative research project uniting participants of Universität Stuttgart, CNRS Gif, Universidad Malaga and Qiagen, Hilden is proposed to utilize the innovative power of rolling circle amplication (RCA) for diagnosis and genomics of viruses with small circular DNA, like geminiviruses and nanoviruses as well as satellite DNAs. Procedures and materials will be developed that allow the centralized analysis of infected plant samples from all over the world, with emphazisis on subtropical and tropical countries. A reference database will be established for plant protection measurements as open access. For functional genomics, RCA-based techniques will be developed to identify relevant genes in the interaction of viruses and hosts, with the primary goal to select or engineer virus resistance. The project is intended to provide added value to crop sustainablity of tomato, cotton, beet and cassava among others.