PVY NTN‐NW , a novel recombinant strain of Potato virus Y predominating in potato fields in Syria

Detailed characterization of a number of isolates of PVY SYR , a novel recombinant strain of Potato virus Y (PVY) from Syria, was conducted to elucidate their origin, assess their significance and achieve a final classification of PVY SYR . Recombination analysis grouped isolates of PVY SYR into three recombination patterns, SYR‐I, SYR‐II and SYR‐III, which varied in the first 700 nucleotides of their genomes, with the second recombination pattern, SYR‐II, the most frequent. PVY SYR isolates shared highest genomic identity and close phylogenetic relationships with PVY NTN and PVY N W isolates from Syria, suggesting a common origin and local emergence of these isolates in Syria. All PVY SYR isolates (total of 20) induced tobacco veinal necrosis, but reacted to a PVY O monoclonal antibody, typical characteristics of the previously reported PVY N W (or PVY N:O ). In potato, however, four isolates tested (one of SYR‐I and three of SYR‐II) induced potato tuber necrotic ringspot disease (PTNRD), which is the characteristic phenotype of PVY NTN . Given the shared properties of SYR‐I and SYR‐II isolates with PVY NTN and PVY N W, it was decided that they represent a new recombinant strain of the PVY N strain group, with the proposed name PVY NTN‐NW . The classification of SYR‐III will be possible only after testing the phenotype in potato. The high prevalence of PVY NTN‐NW in potatoes and weeds, as well as its ability to induce PTNRD, demonstrates its importance and the necessity for its control.