Genomic and biological analysis of Grapevine leafroll-associated virus 7 reveals a possible new genus within the family Closteroviridae.

Deep sequencing analysis of an asymptomatic grapevine revealed a virome containing five RNA viruses and a viroid. Of these, Grapevine leafroll-associated virus 7 (GLRaV-7), an unassigned closterovirus, was by far the most prominently represented sequence in the analysis. Graft-inoculation of the infection to another grape variety confirmed the lack of the leafroll disease symptoms, even though GLRaV-7 could be detected in the inoculated indicator plants. A 16,496 nucleotide-long genomic sequence of this virus was determined from the deep sequencing data. Its genome architecture and the sequences encoding its nine predicted proteins were compared with those of other closteroviruses. The comparison revealed that two other viruses, Little cherry virus-1 and Cordyline virus-1 formed a well supported phylogenetic cluster with GLRaV-7.