Localization of PS9 in rice ragged stunt oryzavirus and its role in virus transmission by brown planthopper

A cDNA of rice ragged stunt oryzavirus(RRSV), coding for its protein PS9, was prepared and expressed in E. coli as a fusion protein, then purified and cleaved by factor-Xa to a 38 kD polypeptide. Using the IgG of the antiserum raised against the expressed fusion protein, the gold immuno-labelling experiments provided a direct evidence that the 38 kD polypeptide is one of the major proteins forming the virus spikes. Virus transmission experiments in brown planthopper fed with PS9 showed the inhibition of transmission of virus by the PS9 protein, suggesting that the spike proteins of the virus may be essential for the virus infection.