First report of Grapevine rupestris vein feathering virus infecting grapevines in Korea

Authors: CHO, IN-SOOK - Rural Development Administration - Korea; CHUNG, B - Rural Development Administration - Korea; Hammond, John; MOON, JAE SUN - Korea Research Institute Of Bioscience And Biotechnology; LIM, HYOUN-SUB - Chungnam National University

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2018
Publication Date: 5/17/2018
Citation: Cho, I., Chung, B.N., Hammond, J., Moon, J., Lim, H. 2018. First report of Grapevine rupestris vein feathering virus infecting grapevines in Korea. Plant Disease. 102:1471. https://doi.org/10.1094/PDIS-12-17-1913-PDN.
DOI: https://doi.org/10.1094/PDIS-12-17-1913-PDN

Interpretive Summary: Virus infections affect both the yield and quality of grapevines, and thus cause considerable economic damage; mixed virus infections are frequently found due to accumulation over the life of the crop and through vegetative propagation. In order to determine which viruses were present in commercial vineyards in two regions of Korea, grapevine leaf samples showing virus-like symptoms and non-symptomatic leaves were collected, nucleic acids extracted, and pooled samples subjected to high-throughput sequencing and analysis to identify plant viral and viroid sequences present. Sequence information was recovered from five virus species and one viroid previously reported in grapes in Korea, and from one virus not previously reported in Korea. Subsequent testing of the original plant samples included in the pooled sample revealed that one virus called GRVFV was present in two asymptomatic plants, which were also infected with Hop stunt viroid as well as three of the other viruses detected in the pooled samples. This is the first report of GRVFV in Korea, suggesting that grapevine nursery stocks should be tested for this and other viruses prior to use for large-scale propagation and establishment of new vineyards.

Technical Abstract: Grapevine rupestris vein feathering virus (GRVFV), a member of the genus Marafivirus in the family Tymoviridae, was first reported from a Greek grapevine causing chlorotic discolorations of leaf veins. The virus has been reported in United States, Canada, Uruguay, Italy, Spain, the Czech Republic and recently in China, Switzerland and New Zealand (Ma et al. 2017; Reynard et al. 2017; Blouin et al. 2017). In 2016, grapevine leaf samples were collected from 10 symptomatic plants showing mottling, yellowing and malformation and 5 asymptomatic plants in commercial vineyards in Gimje and Sangju, 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 23,726,670 reads were assembled and 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 (GPGV), Grapevine geminivirus A (GGVA), and Hop stunt viroid (HSVd) were identified, all of which have been previously reported in Korea. In addition, analysis of five assembled contigs ranging from 236 to 735bp 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 and HSVd, as determined by RT-PCR with virus-specific primers based on the viruses 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.