Based on the known RNA sequence of rice grassy stunt virus , IRRI isolate (RGSV IR), the cDNA of nucleocapsid protein (NCP) gene was obtained by RT PCR, with genomic RNAs of Shaxian isolate (RGSV SX) as template. The cDNA was then cloned into pGEM T vector and sequenced. The results showed that the nucleotide sequence between the two isolates was 99.4% identical. A bacterial expression plasmid pGTNCP which produced a fusion protein with molecular weight of about 62?kD was constructed using the cDNA clone and vector pGEX 2T. Western blot analysis showed that the fusion protein reacted strongly with antibodies raised against RGSV particles. Based on the known RNA sequence of rice grassy stunt virus, IRRI isolate (RGSV IR), the cDNA of nucleocapsid protein (NCP) gene was obtained by RT PCR with genomic RNAs of Shaxian isolate (RGSV SX) as template. The cDNA was then cloned into pGEM T vector and sequenced. The results showed that the nucleotide sequence between the two isolates was 99.4% identical. A bacterial expression plasmid pGTNCP which produced a fusion protein with molecular weight of about 62? kD was constructed using the cDNA clone and vector pGEX 2T. Western blot analysis showed that the fusion protein was strongly strengthened with antibodies raised against RGSV particles.