Variabilidade do gene da proteína capsidial de três espécies virais que infectam videiras no Brasil

Abstract

The purpose of this study was to evaluate the variability of three viruses (Rupestris stem pitting-associated virus - RSPaV, Grapevine leafroll-associated virus 2 - GLRaV-2 and Grapevine fanleaf virus - GFLV) infecting grapevines in Brazil, through molecular characterization of the coat protein (CP) gene. DNA fragments were amplified comprising the complete CP genes of nine isolates of RSPaV (780 bp), six of GLRaV-2 (597 bp) and three of GFLV (1515 bp) by RT-PCR, using specific primers for each viral species. The amplified DNA fragments were cloned and sequenced. RSPaV isolates were clustered into four groups by phylogenetic analysis of the nucleotide (nt) sequences of the CP gene, showing identity values ranging from 81 to 99%. For GLRaV-2, two groups were defined from nt sequences, with identity values ranging from 88 to 99% and for GFLV, two groups were defined with identity values ranging from 89 to 98%. The isolates of each viral species studied here were detected by non-radioactive probes labeled with digoxigenin, allowing unambiguous identification of infected samples, independent of the isolate used as template for probe synthesis.