Grapevine (Vitis spp.) leafroll is a disease caused by up to eight viruses, denominated Grapevine leafroll-associated viruses (GLRaV- 1 to -8), which are serologically unrelated and associated with phloem tissue. In the present paper, GLRaV-1 and -3 were detected by DAS-ELISA in 6.9 and 14.7% of the samples, respectively, and GLRaV-2, -5 and -7 were not detected in grapes. The analysed samples came from two of the most important grape growing regions in Brazil (Serra Gaúcha and Vale do São Francisco). The GLRaV-3 was also identified by dot-ELISA and western blot, associated with a probable coat protein subunit of approximately 36 kDa. A fragment of 340 bp, comprising the 3' terminal of the viral polymerase gene, was PCR-amplified and sequenced. The nucleotide and deduced amino acid sequences of this isolate showed high homology, 95 and 97.1%, respectively, with another GLRaV-3 isolate (NY1).
