Strategies for the control of Plum Pox Virus in apricot in Mediterranean areas

Abstract

Plum pox potyvirus (PPV) is endangering the traditional apricot industry in many Mediterranean countries. In a near future, PPV will be endemic in most early apricot producing areas in which more aggressive PPV isolates are spreading. The molecular knowledge about PPV has considerably increased in the last few years. The complete nucleotide sequence of the genome of several PPV isolates has been determined as well as the function of structural and non structural genes. Methods and reactives for sensitive, simple and reliable detection and typing of PPV have been recently described. Sensitive and specific ELISA-DASI kits for general detection of any PPV isolates (including new cherry strains) or for specific detection of the aggressive serotype M (PPV-M), are now commercially available. This allows the routine distinction of serotypes for eradication purposes. In addition more careful typing of PPV isolates has been successfully assayed using powerful variants of PCR. The recent detection of isolates able to infect parents or cultivars claimed to be resistant to PPV is only an indication of the high variability and pathogenicity of the virus. The panorama for effective control of the disease at mid term is very pessimistic. The majority of the programmes to introduce resistance by conventional breeding methods are based on the use of parents proved to be non resistant. The new biotechnological methods to introduce non structural genes or antibody genes are very promising but they are blocked because it is not yet possible to regenerate transformed apricot varieties. Probably the most logical and practical strategy would be to increase the tolerance to low temperature of some varieties in order to grow them in more continental areas free of PPV. The new material for plantations should be carefully tested in order to avoid the introduction of the disease. The new strategies need the collaboration among breeders, plant pathologists, biotechnologists and agronomists.