The Occurrence and Characterization of New Recombinant Isolates of PVY Displaying Shared Properties of PVYNW and PVYNTN

Isolates of Potato virus Y (PVY), collected in Syria, induced vein necrosis in tobacco but reacted to PVYO monoclonal antibody, and were therefore classified as PVYNW (or PVYN:O). The possible recombinant points within the genome were checked using a previously reported multiplex RT-PCR. These isolates were categorized in two groups according to recombinant points. Isolates with one recombinant point at the HC-Pro/P3, identical to previously reported PVYNW (or PVYN:O), were designated as group 1. However, the majority of Syrian PVY isolates showed two recombinant points at both HCPro/ P3 and 6K2/NIa, revealing a new genomic recombination pattern that had never been reported for PVYNW (or PVYN:O), hereafter referred to as group 2. Further characterizations showed that isolates of group 2 had an additional recombinant point at the N-terminal of the coat protein gene (CP) of their genome. Based on the bioassay on tobacco, serological and molecular studies, these isolates showed shared characteristics of both PVYNW and the recombinant PVYNTN, making it difficult to include them in any of these variants. We propose them as new isolates of PVYN strain, and label them PVYSYR (SYR is from Syria, the country of origin