Abstract: p22 gene was amplified by RT-PCR from CCYV infected melon leaves and cloned into the
prokaryotic expression vector pGex-4T-3. After verification by PCR and sequencing，the recombinant
plasmid was transformed to Escherichia coli strain BL21 for protein expression. The SDS-PAGE analyses
showed that 48 kD specific fusion protein was highly expressed after induction by IPTG. The expressed
protein was purified from SDS-PAGE and the antiserum against the protein was raised in rabbit. The titer
of antiserum was 1.28 × 10⁵ estimated by ACP-ELISA. Western blot analysis confirmed that the antiserum
reacted specifically with P22 protein of CCYV.

Key words: melon, Cucurbit chlorotic yellows virus, P22, prokaryotic expression, antiserum