Identification of grapevines infected with divergent variants of Grapevine virus A using variant-specific RT-PCR.

RT-PCRs, designed for the specific detection of molecular variants of Grapevine virus A (GVA), were applied to analysis of the virus from various grapevines and isolates recovered from these grapevines in Nicotiana benthamiana. Results of SSCP, cloning and sequencing revealed that the combination of these RT-PCR techniques permits reliable and rapid identification of grapevines mixed-infected with divergent variants of GVA. The results suggest that such grapevines are very common among GVA-infected grapevines in vineyards in South Africa.