|DAHAN, JENNIFER - University Of Idaho|
|ORELLANA, GARDENIA - University Of Idaho|
|KARASEV, ALEXANDER - University Of Idaho|
Submitted to: Viruses
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/8/2023
Publication Date: 6/10/2023
Citation: Dahan, J., Orellana, G.E., Lee, J., Karasev, A.V. 2023. Grapevine endophyte endornavirus and two new endornaviruses found associated with grapevines (Vitis vinifera L.) in Idaho, USA. Viruses. 15(6). Article 1347. https://doi.org/10.3390/v15061347.
Interpretive Summary: This paper is the first report on three endornaviruses found in Idaho grapevines from commercially operating vineyards, two of which are new identifications within the United States. Endornaviruses can be found in a range of plants and fungi, often without ill effects to the host. Not all grapevine viruses significantly impact quality, though how this grapevine virus might influence grape quality is not yet know, so further study will be required. As replacing large numbers of vines is not economically feasible for many working vineyards, determining a vine’s virus status is crucial in formulating appropriate viticultural and enological strategies for mitigating virus infections.
Technical Abstract: Five virus genomes ranging between 12.0-12.3-kb in length, identified as endornaviruses were discovered through high throughput sequencing (HTS) analysis of total RNA samples extracted from two wine grape cultivars collected in the State of Idaho. One was found in a declining Chardonnay vine and determined to be a local isolate of grapevine endophyte endornavirus (GEEV), and four others represented two novel endornaviruses named grapevine endornavirus 1 (GEV1) and grapevine endornavirus 2 (GEV2). All three virus genomes span a large, single open reading frame encoding polyproteins with easily identifiable helicase and RNA dependent RNA polymerase (RdRP) domains, while GEV2 polyprotein also contains a glycosyltransferase domain. GEV1 genome revealed in the asymptomatic Cabernet franc is related to but distinct from GEEV: the 5’-proximal, 4.7-kb segment of the GEV1 genome has 72% nucleotide sequence identity to GEEV, while the rest of the genome displays no significant similarity to the GEEV nucleotide sequence. Nevertheless, the amino acid sequence of the RdRP domain of GEV1 exhibited the closest affinity to the RdRP of GEEV. GEV2 was found in declining Chardonnay and in asymptomatic Cabernet franc vines as three genetic variants exhibiting 92-100% nucleotide sequence identity between each other; its RdRP had the closest affinity to Shahe endorna-like virus 1 found in termites. In phylogenetic analyses, RdRP and HEL domains of GEV1 and GEV2 polyproteins were placed in two separate clades inside the large lineage of alphaendornaviruses showing affinity to GEEV and Phaseolus vulgaris endornavirus 1, respectively.