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ARS Home » Northeast Area » Ithaca, New York » Robert W. Holley Center for Agriculture & Health » Emerging Pests and Pathogens Research » Research » Publications at this Location » Publication #309573
Title: Screening potato cultivars for new sources of resistance to Potato virus Y

Author
item ROWLEY, JENNY - University Of Idaho
item Gray, Stewart
item KARASEV, ALEXANDER - University Of Idaho

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2014
Publication Date: 2/1/2015
Citation: Rowley, J., Gray, S.M., Karasev, A. 2015. Screening potato cultivars for new sources of resistance to Potato virus Y. American Journal of Potato Research. 92:38-48.

Interpretive Summary: Potato virus Y is the number one disease affecting seed potato production in the U.S. and is responsible for millions of dollars in annual crop loss and farm income and reduction in domestic and international trade. There are currently no PVY management strategies available to the farmer. Host resistance would be the best means of control, but none of the widely grown and consumer accepted potato varieties have immunity to PVY. Immunity conferring resistance genes do exist and are being bred into potatoes, but this is a long term solution and farmers are in need of a short term fix. Several older potato varieties that are often used to breed new potato varieties have a type of resistance to PVY that operates by causing plant cell death when the plant cells become infected. This type of resistance ultimately kills the infected plant, but it does prevent further spread of the virus and ultimately reduces the number of plants infected by PVY. This study looked at a number of popular U.S. potato cultivars to determine if they possessed this type of resistance and if the resistance was effective against all of the new types of PVY that have emerged in recent years. Resistance genes were identified in several popular potato varieties and many had multiple resistance genes that were effective at slowing the spread of some of the strains of PVY common in the U.S. Unfortunately, these genes are not effective against the strain of PVY that is rapidly becoming the predominant virus strain. These varieties are likely contributing to the rapid rise of virus strains not affected by the resistance genes.

Technical Abstract: Potato virus Y (PVY) strains have been defined based on genetic reactions in potato indicators expressing hypersensitive reaction (HR) response due to the presence of three different N genes, and also based on genomic information. Nine strains are known currently, with five PVY strains defined biologically, PVYO, PVYC, PVYZ, PVYN, and PVYE. The genetic background of the majority of North American potato cultivars has so far been poorly characterized for the presence of N genes inducing HR towards different PVY strains. Here, the HR response was studied in eight potato cultivars, elicited by five strains of PVY circulating in North America. These PVY isolates included representative isolates of PVYN-Wi, PVYNA-N, PVYO, PVYZ, and PVYN strains. Potato cultivars tested included Russet Burbank, Russet Norkotah, Shepody, Ranger Russet, Western Russet, Alturas, Rio Grande Russet, and Yukon Gem, grown in the U.S., and standard indicators Desiree and Maris Bard with the known genetic background. Three additional strains, PVYN:O, PVY-NE11, and PVYE, were tested on Yukon Gem. Virus free potato plants were mechanically inoculated with PVY inoculum, and local and systemic foliar symptoms were observed for 8 weeks post-inoculation under different climate controlled conditions. Virus status of the inoculated plants was tested starting at 3 weeks post-inoculation, by serotype specific ELISA and RT-PCR, in order to monitor successful infections and confirm the identity of the inoculated PVY isolate. This systematic approach allowed us to identify Nytbr and Nztbr genes present in several North American cultivars.