APS Homepage

Oral: Viral Diseases


Epidemiological insights into an emerging virus disease: Blueberry shock virus on cranberry
S. THOMAS-SHARMA (1), L. Wells-Hansen (1), R. Page (1), V. Kartanos (2), E. Saalau-Rojas (3), P. McManus (1) (1) University of Wisconsin-Madison, U.S.A.; (2) Bayer Crop Science, U.S.A.; (3) UMass Cranberry Station, U.S.A.

View Presentation

Berry scarring, where cranberry uprights (shoots) produce scarred, disfigured berries that turn prematurely red, is an emerging problem for growers in WI and MA. We detected Blueberry shock virus (BlShV) on symptomatic uprights using DAS-ELISA and PCR, and initiated epidemiological studies. Similar to BlShV in blueberry, symptomatic cranberry uprights ‘recover’ from symptoms in the following season. These recovered uprights continue to test positive for BlShV and had greater incidence of BlShV in seeds (71%), compared to symptomatic uprights (12%). Studies on yield in three WI marshes affected by BlShV revealed that flowering is comparable in healthy, recovered, and symptomatic uprights. By the time of harvest, symptomatic uprights produced fewer marketable fruit and had lower fruit weight when compared to healthy uprights. Yield components on recovered and healthy uprights were comparable. Phylogenetic analysis of the coat protein of cranberry isolates from WI (n=12) and MA (n=5) revealed 96-100% nucleotide similarity among isolates, and isolates did not group by geography. Analysis of the protein sequence revealed that BlShV on cranberry shares only 90% coat protein identity with BlShV on blueberry. Small RNA sequencing and assembly (sRSA) indicates genome-level single nucleotide polymorphisms in BlShV from cranberry, suggesting different strains on blueberry and cranberry. In-depth analysis of sRSA data to identify other known and unknown viruses is underway.