The Recombinant Potato virus Y (PVY) Strain, PVY^NTN, Identified in Potato Fields in Victoria, Southeastern Australia

Potato virus Y (PVY) is one of the main viruses affecting potato in Australia. However, molecular characterization of PVY isolates circulating in potato in different states of Australia has not yet been thoroughly conducted. Only nonrecombinant isolates of three biological PVY strains collected from potato were reported previously from Western Australia and one from Queensland. Here, PVY isolates collected from seed potato originating in Victoria, Australia, and printed on FTA cards, were subjected to strain typing by RT-PCR, with three isolates subjected to whole genome sequencing. All the 59 PVY isolates detected during two growing seasons were identified to be recombinants based on two RT-PCR assays. No nonrecombinant PVY isolates were identified. All the RT-PCR typed isolates belonged to the PVY^NTN strain. Sequence analysis of the whole genomes of three isolates suggested a single introduction of the PVY^NTN strain to Australia but provided no clues as to where this introduction originated. Given the association of the PVY^NTN strain with potato tuber damage, growers in Australia should implement appropriate strategies to manage PVY^NTN in potato.