Molecular characterisation of segments 1 to 6 of Rice black-streaked dwarf virus from China provides the complete genome

The nucleotide sequences of segments S1 to S6 of a Chinese isolate of Rice black-streaked dwarf virus (RBSDV) were determined. This provides the first complete sequence of a plant pathogenic member of the genus Fijivirus. The complete ten-segment genome has 29141 nucleotides, making it the largest reovirus genome so far reported. Each of the segments S1-S6 is predicted to encode a single major protein. Protein comparisons indicated that S1 encoded an RNA dependent RNA polymerase, with similarities to that encoded by S1 of Nilaparvata lugens reovirus (NLRV). S2 and S3 appeared to be homologous to S3 and S4 respectively of both Fiji disease virus (FDV) and NLRV. The protein encoded on S4 showed some similarity to that of NLRV S2. The proteins encoded on S5 and S6, though similar in size to those of NLRV S5 and S6, had no detectable homologies to them or to any other known protein.