Anthropogenic influences on emergence of vector-borne plant viruses: the persistent problem of Potato virus Y

Authors: Gray, Stewart; POWER, ALISON - Cornell University

Submitted to: Current Opinion in Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/11/2018
Publication Date: 11/11/2018
Citation: Gray, S.M., Power, A. 2018. Anthropogenic influences on emergence of vector-borne plant viruses: the persistent problem of Potato virus Y. Current Opinion in Virology. 33:177-183. https://doi.org/10.1016/j.coviro.2018.10.002.
DOI: https://doi.org/10.1016/j.coviro.2018.10.002

Interpretive Summary: Potato virus Y (PVY) has reemerged over the past 15 years as a serious impediment to seed potato production, responsible for reduced yields and tuber quality, as well as the majority of seed lot rejections by certification programs due to excessive virus incidence. This has led to seed shortages, especially in cultivars highly susceptible to infection. Seed certification programs have been effective at managing many virus diseases below economic thresholds and with some changes can once again manage PVY. In the past decade PVY has rapidly changed from a virus that causes a disease easily observed by seed inspectors and farmers to one that causes a cryptic disease that easily escapes detection. Plants with visible symptoms can be removed by farmers and the amount of virus in the crop is accurately determined by regulators. This prevents the continued propagation of virus in the crop. If the diseased plants are not detected they remain in the field and contribute to a high incidence of disease in the harvested tubers used to plant the next year’s crop. Exacerbating the issue is the unintended incorporation of partial resistance into many potato cultivars by breeders. This resistance has also selected for new virus strains that are not controlled by the resistance. While the virus naturally evolves to be less severe, the regulatory and breeding practices have sped up the process. Seed certification programs will need to make adjustments to be able to detect the new viruses and once again accurately estimate disease levels so that highly diseased seed potatoes can be removed from the supply chain.

Technical Abstract: Potato virus Y (PVY) has reemerged as a serious impediment to seed potato production, responsible for reduced yields and tuber quality, as well as the majority of seed lot rejections by certification programs due to excessive virus incidence. This has led to seed shortages, especially in cultivars highly susceptible to infection. While seed certification programs have been effective at managing many virus diseases below economic thresholds, PVY has rapidly evolved in recent decades to become a complex of strains that evade many certification and farm management practices. The evolution of PVY strains is naturally occurring, but several human influences can be linked to the rapid change in PVY populations affecting the potato crop. Here we highlight the recent history and current status of PVY in potatoes and suggest some approaches for managing the virus moving forward.