First unambiguous report of potato virus Y strain N-Wilga (PVY N-Wi ) in Canada

Potato virus Y (PVY, Potyvirus yituberosi) is one of the most economically important viruses affecting potato crops worldwide, with recombinant strains increasingly dominating in many production regions. Among these, PVY strain N-Wilga (PVYN-Wi) has been widely reported in Europe, Asia and the United States but has not been previously confirmed in Canada. In this study, we report the first unambiguous detection and characterization of a PVYN-Wi isolate from New Brunswick, Canada. The isolate was initially identified by multiplex RT-PCR and subsequently confirmed by full-genome sequencing. The genome (9698 nt) shared ≥ 99% nucleotide identity with previously reported PVYN-Wi isolates from western USA and Europe, and shows characteristic recombination junctions in the P1 and HC-Pro/P3 regions. A modified RT-PCR assay was developed to improve detection of the P1 recombination junction. Serological assays demonstrated a PVYO serotype, consistent with coat protein origin, while pathological assays showed a PVYN-type response in tobacco. In potato only mild foliar symptoms developed, without tuber necrosis in the typically susceptible cv. Yukon Gold. The combination of mild symptoms and serological profile suggests that PVYN-Wi may evade standard detection and management strategies. These findings confirm the presence of PVYN-Wi in Canada and highlight the need for continued surveillance of this strain.