Generating durable resistance to potexviruses in vegetabel crops by identification of key host susceptibility factors

P582 - Viral infections cause detrimental diseases in vegetable and field crops. Amongst these, Potato Virus X (PVX), belonging to the genus Potexvirus, causes major yield losses in Solanaceous species such as potato and tomato. Although dominant resistance against PVX already exists, strains of PVX have been detected that are capable of breaking the resistance response mediated by the potato immune receptor Rx. This fact calls for new means of obtaining durable resistance to potexviruses. Due to their biology, viruses depend on host proteins in order to infect plants. As these proteins render the plant susceptible, they are known as host susceptibility targets. We hypothesize that manipulation of such host proteins, which are required for completing the infection cycle of potexviruses in general, provides leads for generating durable resistance to this type of viruses. To identify host susceptibility targets we perform random silencing in Nicotiana benthamiana by Virus-Induced Gene Silencing (VIGS) of a normalised cDNA library of this plant, followed by inoculation with GFP-labelled PVX. As wild-type N. benthamiana is susceptible to PVX, we expect that silencing of an essential plant susceptibility target will result in reduced PVX accumulation and/or spread. Moreover, we also aim to identify plant proteins interacting with the different viral proteins by in planta immunoprecipitation assays in N. benthamiana , as well as by yeast two-hybrid cDNA library screens. Preliminary data obtained with all three approaches will be presented.