Whole Genome Sequence and Characterization of a Novel Isolate of PVY Inducing Tuber Necrotic Ringspot in Potato and Leaf Mosaic in Tobacco

In a previous study on a Syrian isolate of Potato virus Y (PVY), namely PVY‐12, a point mutation in the coat protein (CP) was detected. This mutation caused the double reactivity of this isolate to monoclonal antibodies specific to O and N serotypes. We report here the biological and molecular characteristics of PVY‐12. In potato, PVY‐12 behaved like a PVYNTN isolate inducing potato tuber necrotic ringspot disease although it induced mosaic in tobacco like PVYO. The genomic analysis grouped PVY‐12 with the recombinant PVYNTN isolates, which is consistent with the phenotype in potato. PVY‐12 HC‐Pro had the two amino acids K400 and E419 that were previously reported as determinant keys of the tobacco necrotic response. This indicates the involvement of other determinants in this phenotype yet to be determined. This is the first report on a PVYNTN isolate that induces mosaic in tobacco, implying that the induction of potato tuber necrosis does not require the ability to induce the tobacco necrosis. PVY‐12 genome had four recombinant points in the P1, HC‐Pro/P3, 6K2/NIa and C terminal region of the CP gene identical to those of PVYNTN isolates 12–94 and 34/01. The PVY‐12 central genomic part flanked by nucleotide positions 2414 and 8604 had highest similarity with that of the Syrian isolate SYR‐NB‐16 suggesting a common origin of these isolates. This common origin was supported using the phylogenetic analysis of this region. In addition, the phylogenetic analysis of the whole genome of the reported North American PVYN:O and the European PVYNW along with other PVY isolates suggests that PVYN:O might have descended from PVYNW with the isolate SASA‐207 as a nearest‐known relative.