First report of Grapevine rupestris vein feathering virus and Grapevine tymo-like virus in Oregon wine grapes

Grapevine rupestris vein feathering virus (GRVFV) was originally found in association with vein feathering symptoms in a Greek grapevine cultivar (El Beaino et al. 2001; Ghanem-Sabanadzovic et al. 2003), and later in a declining Syrah vine (Al Rwahnih et al. 2009). GRVFV was reported in California (Al Rwahnih et al. 2009), Washington (Chingandu et al. 2021), and Idaho (Dahan et al. 2021). Grapevine-associated tymo-like virus (GaTLV) was found in grapevines in France (Hily et al. 2018), in Tennessee (Hu et al. 2021), and in Idaho (Dahan et al. 2023). In September 2024, four Petite Sirah vines were sampled in the 12-year-old block (0. 6 ha) of a vineyard in Malheur County, Oregon. Three of the vines exhibited leaf reddening symptoms suggestive of a virus infection, while one was visibly asymptomatic. RNA was extracted from leaf and petiole tissues using the Spectrum Plant Total RNA Kit (Sigma-Aldrich, St. Louis, MO) (Dahan et al. 2021), followed by ribosomal RNA depletion and high-throughput sequencing (HTS) on a NovaSeqX platform by Psomagen (Frederick, MD). HTS produced between 25, 460, 282 to 27, 173, 298 150-bp paired-end reads per sample. After quality-filtering and mapping to a reference Vitis vinifera L. genome, de novo assembly of the unmapped reads resulted in 1, 054 to 2, 077 contigs over 1, 000 nt in length. BLASTn analyses identified a 6, 675-nt contig in a symptomatic Petite Sirah sample, exhibiting 86. 4% identity to a Canadian GRVFV isolate (MZ451083). This virus sequence was named GRVFV-OR and deposited under the accession number PX873517. The presence of the GRVFV-OR was confirmed in the original RNA sample using RT-PCR and primers GRVFV-ORF1: 5′-CGTCCTTCTCGCGATGACC-3′ and GRVFV-ORR1: 5′-AGGTCGCTTTACGGACCTTTTCTT-3′ amplifying a 639-bp product. The PCR product was cleaned-up using ExoSAP-IT (Thermo Fisher Scientific, Waltham, MA), and submitted to Elim Biopharmaceuticals, Inc. (Hayward, CA) for sequencing. This Sanger sequence was 99. 8% identical to the HTS-derived one. In September 2025, a total of 19 vines from five cultivars, Cabernet Sauvignon, Muscat Blanc, Petite Sirah, Tempranillo, and Verdejo were sampled in the same vineyard in Malheur County, OR. These were subjected to RT-PCR testing for GRVFV using GRVFV-ORF1/R1 primers and for GaTLV using the GaT2 primer set described previously (Dahan et al. 2023). Of the 19 samples tested, nine were found positive for GRVFV and seven were found positive for GaTLV. Sequencing of the seven GRVFV-specific PCR products revealed a nucleotide identity of 86. 4-98. 9% to the HTS-derived sequence of GRVFV-OR (PX873518-PX873524), suggesting substantial genetic diversity of GRVFV within the same vineyard. Apparently, different genetic variants of GRVFV were introduced into this vineyard in Oregon multiple times in different grapevine cultivars. At the same time, GaTLV-specific products from Cabernet Sauvignon, Tempranillo, and Petite Sirah (PX873525-PX873531) were over 99. 5% identical to the GaTLV isolate sequence reported from Idaho (ON853768) suggesting very low genetic diversity of the virus, at least in the genetic region under study. Previous studies documented GRVFV association with decline in Syrah vines (Al Rwahnih et al. 2009). GRVFV was found in the symptomatic Petite Sirah vine in 2024, hence its potential contribution to berry yield and quality losses needs further research. To the best of our knowledge, this is the first report of GRVFV and GaTLV in Oregon grapevines.