Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2008
Publication Date: 7/1/2008
Citation: Gray, S.M., Karasev, A., Lorenzen, J., Whitworth, J.L., Nolte, P., Perry, K. 2008. Emerging diversity in Potato virus Y poses new challenges for the U.S. potato industry. Phytopathology. 98:S61.
Technical Abstract: Until recently tobacco and potato tuber necrotic strains of Potato virus Y (PVY) were considered to be absent from the U.S., and seed certification programs were able to limit PVY incidence in seed potatoes. PVY has become more problematic in recent years and beginning in 2002, necrotic strains of PVY isolated from potato were reported from several growing regions. A three year survey of PVY strains infecting the U.S. seed potato crop was conducted by sampling tubers from most late generation seed potato fields in all production areas in 16 states. PVY isolates were characterized using serology, plant bioassays, and nucleic acid-based diagnostics. Over 200,000 tubers were tested using ELISA; nearly 9100 tested positive for PVY, and to date over 2300 isolates have been characterized using all the above mentioned diagnostics. Twelve unique phenotypic groups of PVY were identified, 5 of which were found in significant numbers. Additionally, sequence information has identified over 30 different genotypes, although most have not been linked to specific phenotypes. Interestingly recombination between necrotic and non-necrotic strains is responsible for much of the genetic diversity, with 7 unique recombinant genotypes identified to date. Another significant finding is the widespread distribution of a non-necrotic strain that has a single amino acid change in the coat protein that is recognized by a necrotic ‘strain-specific’ monoclonal antibody. Isolates in strain groups other than PVY(^NTN) have been observed to induce potato tuber necrotic ringspot disease, and a range of tuber symptom types have been observed. The recent emergence of genetic diversity within PVY poses a threat to potato production and requires immediate changes in PVY disease management strategies.