The complete genome sequence of polygonum ringspot virus

The complete genome sequence of polygonum ringspot virus (PolRSV), genus Tospovirus, family Bunyaviridae, was determined. This is the first report of the complete genome sequence for a European tospovirus isolate. The large RNA of PolRSV was 8893 nucleotides (nt) in size and contained a single open reading frame of 8628 nucleotides in the viral-complementary sense, coding for a predicted RNA-dependent RNA polymerase of 330.9 kDa. Two untranslated regions of 230 and 32 nucleotides were present at the 5′ and 3′ termini, respectively, which showed conserved terminal sequences, as commonly observed for tospovirus genomic RNAs. The medium and small (S) RNAs were 4710 and 2485 nucleotides in size, respectively, and showed 99 % homology to the corresponding genomic segment of a previously partially characterized PolRSV isolate, Plg3. Protein sequences for GN/GC, N and NSs were identical in length in the two PolRSV isolates, while an amino acid insertion was observed for the NSm protein of the newly characterized isolate. The noncoding intergenic region of the S RNA was very short (183 nt) and was not predicted to form a hairpin structure, confirming that this unique characteristic within tospoviruses, previously observed for Plg3, is not isolate specific.