The two major proteins found in plants infected with rice stripe virus (RSV), coat protein and a major nonstructural protein (major NS), were purified and their partial amino acid sequences were determined. Oligonucleotides were synthesized according to the amino acid sequence information, and used as probes for Northern blot analyses of four single-stranded RNA species (segments 1-4) and four double-stranded RNA species of RSV. The results indicated that the coding strategy of RSV was similar to those of ambisense viruses: Segment 3 coded for the coat protein in the (-) sense while segment 4 coded for the major NS protein in the (+) sense.