Molecular characterization of a grapevine leafroll-associated virus 4 from Slovenian vineyards

During a survey conducted in vineyards in Slovenia, variety of grapevine leafroll disease symptoms were observed. Mixed infection with grapevine leafroll-associated viruses 3 and 4 (GLRaV-3, -4) in two grapevines from a vineyard in south-western part of Slovenia was confirmed by DAS-ELISA in 2010. The 3'final 1769 nucleotides of the Slovenian GLRaV-4 isolate were assembled from amplicons obtained by IC RT-PCR. The complete coat protein (CP) and p23 gene sequences were compared with other GLRaV-4 sequences from GenBank. Results showed that CP and p23 amino acid sequences of Slovenian variant (055-SI) are 88% and 85%, respectively, identical to corresponding genes of reference sequence GLRaV-4 LR106 (GenBank Acc. No. FJ467503). Phylogenetic analyses show that Slovenian variant clusters together with other corresponding strains of GLRaV-4. The sequencing results show great variability of the N-terminal part of the CP sequence indicating that this part of the genome is not suitable for molecular detection of the virus. To our knowledge this is also the first report of GLRaV-4 in Slovenian vineyards.