First Report of Grapevine rupestris vein feathering virus Infecting Grapevines in Korea

Abstract

Grapevine rupestris vein feathering virus (GRVFV), a tentative member of the genus Marafivirus in the family Tymoviridae, was first reported from a grapevine with chlorotic discolorations of leaf veins in Greece (El Beaino et al. 2001; Ghanem-Sabanadzovic et al. 2003). The virus has been reported in United States, Canada, Uruguay, Italy, Spain, the Czech Republic, and recently in China, Switzerland, and New Zealand (Blouin et al. 2017; Ma et al. 2017; Reynard et al. 2017). In 2016, grapevine leaf samples were collected from 10 symptomatic plants showing mottling, yellowing, and malformation, as well as from five asymptomatic plants in commercial vineyards in Gimje and Sangju, Republic of Korea. Total RNA was extracted, pooled, and used for constructing a cDNA library followed by high throughput sequencing (HTS) on an Illumina HiSeq 4000 platform at Macrogen Inc. (Seoul, Korea). A total of 23,726,670 reads were obtained and assembled contigs were blasted against reference sequences for viruses and viroids. From the HTS data, contigs derived from Grapevine leafroll-associated virus 3 (GLRaV-3), Grapevine fleck virus (GFkV), Grapevine rupestris stem pitting-associated virus (GRSPaV), Grapevine Pinot gris virus, Grapevine geminivirus A, Hop stunt viroid (HSVd), and Grapevine yellow speckle viroid 1 (GYSVd-1) were identified, all of which have been previously reported in Korea. In addition, analysis of five assembled contigs ranging from 236 to 735 bp showed the presence of GRVFV; these contigs shared identities of 83.5 to 87.0% with GRVFV isolates in GenBank. To confirm the presence of GRVFV, RT-PCR was performed using previously reported primers GRVFV_6156F and GRVFV_6600R (Reynard et al. 2017). PCR products of the expected 445 bp were obtained from two asymptomatic plants of the 15 grapevine samples, sequenced, and found to be identical. The sequence (GenBank accession no. LC333376) showed 87.4 and 89.4% identity to GRVFV isolates from Switzerland (KY513702) and New Zealand (MF000325), respectively. The asymptomatic GRVFV-positive plants were also coinfected with GLRaV-3, GFkV, GRSPaV, HSVd, and GYSVd-1 as determined by RT-PCR using primers specific to virus and viroid sequences obtained from the HTS results (data not shown). GRVFV infected grapevines cv. Shine Muscat did not display any characteristic symptoms. To our knowledge, this is the first report of GRVFV infecting grapevines in Korea.