ADVANCES IN THE DETECTION OF GRAPEVINE LEAFROLL-ASSOCIATED VIRUS 2 VARIANTS

Several detection methods were compared, as a guide for the development of the most efficient diagnostic tools for the broad specificity or specific identification of Grapevine leafroll-associated virus 2 (GLRaV-2) variants. To this aim, comparative trials were carried out using a group of distinctive GLRaV-2 variants, the GLRaV-2-RG strain and a new strain, called GLRaV-2- BD. ELISA detected all GLRaV-2 isolates when the tested samples contained a sufficiently high concentration of the antigen. RT-PCR was more sensitive than ELISA, but did not recognise all the GLRaV-2 sequence variants under investigation. New primer pairs were therefore designed, some of which allowed the simultaneous detection of all isolates, while others were specific to each variant. The universal primer pairs for GLRaV-2, together with RFLP analysis, allowed a rapid identification and characterisation of GLRaV-2 variants with divergent sequences.