Potato virus Y (PVY) infects a wide host range mainly within the Solanaceae and is distributed worldwide. PVY is transmitted by more than 40 aphid species in a non persistent manner. Isolates of the PVY species are highly variable at biological, serological and molecular levels. Epidemiological studies have highlighted the emergence of distinct potato PVY variants able to induce necroses on potato tubers. Due to the lack of efficient resistance to PVY isolates inducing necrotic symptoms in cultivated varieties and the plant-to-plant transmission of isolates through the daughter tubers, PVY has become the most economically important virus for the potato industry. The review offers an overview of several decades of research on PVY but also focuses on the latest data obtained by expert on PVY worldwide on the biological characteristics of PVY, interactions between aphids-hosts, its evolution and management. Identified knowledge gaps to understand further PVY biology will be discussed.

Traditionally, 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 different N genes. Currently, there are five known PVY isolates: PVYO, PVYC, PVYZ, PVYN, and PVYE, with PVYC and PVYE being uncommon in North America. The genetic background of North American potato cultivars, thus far, has been poorly characterized for the presence of N genes producing HR response to various PVY strains. I studied HR response in eight potato cultivars, (Russet Norkotah, Ranger Russet, Russet Burbank, Alturas, Western Russet, Yukon Gem, Rio Grande, and Shepody) induced by five strains of PVY commonly circulating in North America. A number of these cultivars were found to contain N genes - including a several new putative N genes. In order to support my findings of a putative gene Nztbr (that was proposed to confer resistance against the distinct strain PVYZ ), I report on a genetic study of the Nztbr inheritance in crosses between three cultivars. The cultivars chosen were Maris Bard (Ny:Nz), King Edward (ny:nz), and Russet Norkotah (ny:nz). These crosses subsequently proved the existence of Nztbr - which is a nuclear gene. For our research, as well as for potato seed certification programs, significant amounts of specific antibodies for large-scale screenings are required. Sandwich ELISA assays, the most convenient method, require antibodies from different animal species. Unfortunately, this adds complexity to reagent production. Here, I describe a biotechnological approach to circumvent the problem of host protein contamination of the antigen for potato viruses. I developed detection systems for six potato viruses, PVY, PVS, PVX, PVA and PLRV. This document, as a whole, improves detection methods for potato viruses and describes a new way of looking at resistance.