The complete nucleotide sequence of RNA 1, the largest genomic segment of rice stripe virus (RSV), was determined using two sets of overlapping cDNA clones.

The complete nucleotide sequence (3514 nucleotides) of RNA segment 2 office stripe virus (RSV), the prototype member of tenuivirus group, was determined. In the virus-sense RNA an open reading frame (ORF) is present which encodes a 199 amino acid protein of M r 22 762. Another long ORF encoding an 834 amino acid protein with M r 94047 (94K) exists in the viruscomplementary RNA. Between these two ORFs, there is a long non-coding intergenic region of 299 nueleotides.The sequence suggests that RNA 2 has an ambisense coding strategy as found for RSV RNAs 3 and 4. The putative 94K protein carries stretches with an amino acid sequence showing weak similarity to parts of the membrane glycoproteins of Punta Toro and Uukuniemi phleboviruses of the family Bunyaviridae, suggesting a possible distinct evolutionary relationship between the animal phleboviruses and the plant tenuiviruses.

The RNA 3 of rice stripe virus (RSV) isolate T was cloned and its nucleotide sequence was determined.

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 M, 20541, and the other ORF, in the 5'-proximal region of the viral complementary sense RNA, encodes an unknown protein with Mr 32 474. 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 noncoding 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.

The coat protein (CP) gene of rice stripe virus was introduced into two japonica varieties of rice by electroporation of protoplasts. The resultant transgenic plants expressed the CP at hih levels (up to 0.5% of total soluble protein) and exhibited a sinifcant level of resistance to virus infection. Plants derived from seLfed progeny of the primary transformants also expressed the CP and showed viral resistance, idicating stable transmission of the CP gene and the trait of resistance to the next generation. Moreover, the virally encoded stripe disease-specific protein was not d d in trbnsgenic plants expressing CP 8 weeks after oculation, indicating protection before viral multiplication. These studies demonstrated that CP-mediated resistance to virus infection can be extended to cereals and to the viruses transmitted by an insect vector (planthopper).