|Grapevine red blotch-associated virus is widespread in United States vineyards|
B. Krenz (1), J. R. Thompson (1), H. L. McLane (1), M. FUCHS (2), K. L. Perry (1). (1) Cornell University, Ithaca, NY, U.S.A.; (2) Cornell Univ, Geneva, NY, U.S.A.
Grapevine red blotch-associated virus (GRBaV) is highly correlated with red blotch, a recently recognized disease of grapevines. This virus is tentatively assigned to the family <i>Geminiviridae</i> with limited significant affinities to members of recognized genera and novel plant-infecting gemini-like viruses. To determine the distribution and genetic variability of GRBaV isolates, more than one hundred infected grapevine samples were collected in or received from vineyards in eight states (AR, CA, MD, NJ, NY, OR, PA and VA), demonstrating a widespread occurrence of the virus in the United States. Phylogenetic analyses of a viral replication-associated protein (Rep) gene fragment from 42 isolates of GRBaV demonstrated two distinct clades, with clade 1 showing the greatest variability and clade 2 grouping the majority of isolates. The full-length genome of six GRBaV isolates was sequenced and phylogenetic analyses of 14 whole genomes recapitulated phylogenetic relationships seen for the Rep gene. A comparison of GRBaV genomes indicated recombination events underlying some of the variation seen among isolates within clade 1. These results shed light on the distribution and genetic variability of the newly identified GRBaV.