Abstract: The 3′ terminal of SDV（Satsuma dwarf virus）RNA2 was amplified from two plants of Miyamoto Satsuma mandarin from Fengjie in Chongqing by RT-PCR. The amplified fragments are 975 bp in size and share 98.7% and 98.4% nucleotide identities with that of SDV S-58，respectively. The small coat protein（CPS）gene with a size 654 bp of SDV-FJ was amplified from the plasmid containing the SDV RNA2 3′ terminal by PCR and cloned into the prokaryotic expression vector of PGEX-6p-1 to construct a recombinant vector named PGEX-CPS. The recombinant plasmid was transformed into E. coil BL21 to express the GST-CPS protein in the optimized condition. GST-CPS protein was purified to immunize rabbit for preparing anti-CPS antibody. The results showed that the 42 kD GST-CPS protein was successfully expressed in E. coil BL21 induced with 0.3 mmol · L-1 IPTG at 28 ℃. Anti-CPS antibody with the title of 1/12 800 was obtained from the rabbit immunized with the purified GST-CPS protein. The result of tissue bolt with the anti-CPS antibody showed that the base of petiole contain more SDV than other tested tissues of infected Miyamoto Satsuma mandarin.

Key words: citrus, Satsuma dwarf virus, small coat protein, prokaryotic expression, antiserum