Characterization of potato Y potyvirus isolates from tomato crops in Islas Canarias (Spain)*

A disease caused by potato Y potyvirus (PVY) affects tomato plantations with variable severity in Tenerife Island. Affected plants show diverse symptoms such as necrotic lesions or mild to severe mosaic in leaves and whitish spots in green fruits that remain after ripening. Tomato PVY isolates and few potato and capsicum PVY isolates have been characterized on the basis of biological, serological and molecular criteria. All PVY isolates reacted positively to monoclonal antibodies specific for PVY^O/C or PVY^N strains, and nearly 50% of tomato PVY isolates were recognized by both. Differentiation of PVY strains according to the response of inoculated experimental plants was confusing due to the variability of viral aggressiveness and symptomatology induced. RFLP analysis of the CP gene and 3’untranslated region (UTR) revealed high variability. In addition to mixed infection by different PVY strains, the biological and molecular properties of those tomato PVY isolates that react to both monoclonal antibodies could be explained as the result of RNA recombination between distinct PVY strains which infect the same host plant.