Complete nucleotide sequence of RNA 4 of rice stripe virus isolate T, and comparison with another isolate and with maize stripe virus.

The complete nucleotide sequence of RNA 4 of rice stripe virus isolate T (RSV-T) was determined and found to consist of 2157 nucleotides, containing two open reading frames (ORFs). One, deduced to be present in the 5'-proximal region of the viral-sense RNA, encodes the stripe disease-specific protein with Mr 20541, and the other ORF, in the 5'-proximal region of the viral complementary sense RNA, encodes an unknown protein with Mr 32474. Between these two ORFs there is an intergenic non-coding region that could form a secondary structure with two base-paired hairpin configurations. These characteristics indicate that RSV-T RNA 4 has an ambisense coding strategy. Comparison of the two ORFs of RSV-T with those of another isolate revealed 97.2% and 98.0% identity for the nucleotide sequences, and 98.3% and 98.2% identity for the amino acid sequences. The leader sequences of these two isolates were the same. However, an insertion was found in the intergenic non-coding region of RSV-T. Furthermore, comparison of the nucleotide and amino acid sequences of RSV-T RNA 4 with those of RNA 4 of maize stripe virus, which is another member of the tenuivirus group, revealed greater identity, suggesting a close phylogenetic relationship between these two viruses.