Abstract: Total RNA of potato virus S (PVS)was isolated from diseased potato leaves collected in
field，The cDNA encoding PVS coat protein(PVS-cp)was amplified by RT-PCR and cloned into the plasmid
pGEM—T vector． The expression vector of P 一cp gene was constructed through inserting the cDNA fragment
into the expression plasmid pBV220． The results of SDS-PAGE and W estern blot analysis showed that
the P -cp gene highly expressed in E．coli JM109 and the molecular size of the expression product was about
33 kD． The product was used as antigen to immunize rabbits and the specific anti-serum can be used to detect
PVS rapidly．

Key words: Potato, Potato virus S, Coat protein gene, RT-PCR, Sequence analysis, Western blot, Anti-serum preparation