Plant viruses cause an estimated 50 billion € loss worldwide per year. Viral diseases represent one of the most limiting factors in European crop production having negative effects on the quantity and quality of foodstuffs. The recent identification of plant factors required for virus infection, together with the development of functional genomic tools in several economically important crops, offer novel opportunities to protect crop plants against viral diseases. The scope of TESS is to capitalize on the latest biotechnological tools in order to manipulate the plant/virus interactions towards non-host resistance and to match the research outputs with fruit industry and breeding applications. TESS benefits from multidisciplinary research teams involving genomics, tissue culture, molecular biology, virology and plant breeding. It focuses on Prunus species for stone fruit trees. Our goal in TESS is to engineer Prunus susceptibility genes either to create, by genome editing, a collection of de novo non-functional susceptibility genes (i.e. Knocked-Out KO genes) or to target specific amino-acids which are relevant for compatible plant/virus interactions, without knocking-out the host gene(s), to avoid any side effect for the plant. They will later be combined with over-expressed flowering time regulator cassettes, to promote early flowering, shorten the juvenile phase and allow rapid selection of mutants in those perennial species. The originality of TESS is to test the generic mode of interference of plant viruses with their host during the infection and use this information to implement complex and durable resistance in perennial fruit tree species.
