First report of grapevine rupestris vein feathering virus in grapevine in Slovakia.
Grapevine rupestris vein feathering virus (GRVFV), a tentative member of the genus Marafivirus (family Tymoviridae), was originally reported from a Greek source of Vitis vinifera 'Sultanina' displaying asteroid-like symptoms and eliciting vein feathering symptoms upon grafting on Vitis rupestris. In August 2017, samples consisting of main veins of fully developed leaves of two grapevine plants were used for total RNA isolation. Ribosome-depleted RNA preparations were used for cDNA library synthesis followed by high-throughput sequencing (HTS) on an Illumina MiSeq platform (300-bp paired-end sequencing). BLAST analyses of contigs assembled from HTS reads from these grapevine samples, referred to as SK809 and SK933, indicated the presence of multiple virus infections, including GRVFV (a total of 137 and 288 reads, respectively), mapped to the reference GRVFV genome. The contigs from SK809 (530 bp) and SK933 (1 959 bp) showed 82 and 85% identity, respectively, to GRVFV. BLAST analyses revealed the additional presence of Grapevine leafroll-associated virus 1 (GLRaV-1) and Grapevine virus T in SK809 and GLRaV-2, GLRaV-3, Grapevine rupestris stem pitting-associated virus, Grapevine Syrah virus 1, and Hop stunt viroid in SK933. A pool of grapevine samples from four localities in western Slovakia was screened by reverse transcription polymerase chain reaction to confirm the presence of GRVFV. Phylogenetic analysis of all corresponding available partial sequences in GenBank and 14 Slovak isolates suggested the existence of two molecular groups. These results indicate multiple introductions of GRVFV in the country. This is thought to be the first report of GRVFV infecting grapevines in Slovakia.