The aim of this programme is to breed the genetic resistance to Sharka disease in the cultivated Prunus spp. This disease causes severe losses on the crops of stone fruits and occurs at different levels in the most of the European countries, where hundreds millions trees are infected. It is a great menace for the mondial fruit production.
Sharka disease causes severe losses in crops of stone fruits and occurs at different levels in most European countries, where hundreds of million of trees are infected. There is a need for cultivars resistant to the disease and also better methods of detection of the disease to give guarantees of plant health for both Community and international trade. Research is underway to breed genetic resistance to sharka disease in the cultivated Prunus species and to develop methods of detection of the disease.
In relation to methods of detection, several monoclonal and polyclonal antibodies have been obtained and polymerase chain reaction (PCR) and immunocapture PCR techniques have also been tested. Peach and plum trees showing resistance to sharka virus are difficult to find but such resistance if found in apricot. Genetic transformations have been made using young tissues of Prunus. In vitro methods for the evaluation of resistance to sharka have been developed. Epidemiological studies on the transmission of sharka have been carried out on apricot and peach trees. The role of insect aphids as a vector of sharka has been emphasized.
The above objectives will be realized through five points :
1. Production of serological or molecular reactifs (probes, PCR).
2. Comparison of these techniques for the detection of different isolates after inoculation.
3. Research of resistant genitors and breeding of the varieties by conventional methods.
4. Obtention of transgenic plants expressing the protein capsid gene of the virus and regeneration of plants. Evaluation of the behaviour of the transformed plants.
5. Effect of resistant plant or not upon the epidemiology of the disease and the aphid transmission.
The main expected results are the selection of resistant genitors and their use in the Prunus breeding programme, a better efficiency of the methods of detection in order to obtain high sanitation guarantees for the Open Common Market and international trade.