|QUITO-AVILA, D - Centro De Investigacion|
|CLINE, W - North Carolina State University|
|HARMON, P - University Of Florida|
|BRANNEN, P - University Of Georgia|
Submitted to: International Conference on Graft Transmissible Diseases of Fruit Crops
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2012
Publication Date: 6/3/2012
Citation: Martin, R.R., Quito-Avila, D.F., Cline, W.O., Harmon, P.F., Brannen, P.M. 2012. An emerging disease in blueberry caused by a novel RNA virus. Abstract for: 22nd International Conference on Graft Transmissible Diseases of Fruit Crops, June 3-8, 2012, Rome, Italy.
Technical Abstract: A new disorder was observed on southern highbush blueberry (Vaccinium corymbosum interspecific hybrids) in several southeastern states. Symptoms included irregularly shaped circular spots or blotches with green centers on the top and bottom of leaves. The disease was reported initially in the state of Georgia in 2006 and 2007, but in 2008 it was found in production areas in the states of Florida, Mississippi, South Carolina, and North Carolina. Diagnostic tests failed to isolate any fungal or bacterial pathogens typically associated with such symptoms. Double-stranded RNA (dsRNA) extracted from symptomatic leaves suggested the presence of virus(es) possibly involved in the disease. Sequencing revealed the presence of a novel virus with a genome of ~14 kb divided into 4 positive-sense RNA segments. Primers developed from conserved areas of the RdRp detected the virus in more than 50 individual plants that exhibited necrotic ring blotch symptoms in North Carolina, Georgia and Florida. The perfect correlation between the virus and symptoms in plants from across several states suggests that the virus, for which we propose the name Blueberry necrotic ring blotch virus (BNRBV), is the causal agent of the disease. Sequence analysis showed that BNRBV possesses protein domains conserved across ssRNA viruses from the Virgaviridae, Bromoviridae and the newly created genus Cilevirus. Furthermore, BNRBV has two Helicase (HEL) domains located on RNA 1 and 2. Both HEL domains possess conserved motifs and, more importantly, represent two distinct clades indicating virus recombination events as a result of co-infections.