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Updated: May 17, 2026

Combining Analysis of DNA in a Crude Virion Extraction with the Analysis of RNA from Infected Leaves to Discover New Virus Genomes
Published on: July 27, 2018
A divergent variant of Grapevine leafroll-associated virus 3 is present in California
Yeemey Seah1, Abhineet M Sharma, Siming Zhang
1Department of Ecology, Evolution and Natural Resources, School of Environmental and Biological Sciences, Rutgers the State University of New Jersey, 14 College Farm Rd, New Brunswick, NJ 08901, USA.
Background:
Grapevine leafroll-associated viruses are a problem for grape production globally. Symptoms are caused by a number of distinct viral species. During a survey of Napa Valley vineyards (California, USA), we found evidence of a new variant of Grapevine leafroll-associated virus 3 (GLRaV-3). We isolated its genome from a symptomatic greenhouse-raised plant and fully sequenced it.
Findings:
In a maximum likelihood analysis of representative GLRaV-3 gene sequences, the isolate grouped most closely with a recently sequenced variant from South Africa and a partial sequence from New Zealand. These highly divergent GLRaV-3 variants have predicted proteins that are more than 10% divergent from other GLRaV-3 variants, and appear to be missing an open reading frame for the p6 protein.
Conclusions:
This divergent GLRaV-3 phylogroup is already present in grape-growing regions worldwide and is capable of causing symptoms of leafroll disease without the p6 protein.
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