Sequencing and construction of plant expression vector of coat protein gene from Ys strain of pa- paya ringspot virus

The cloned coat protein (CP) gene from Ys strain of papaya rinspot virus (PRV) was sequenced by dideoxy-chain termination method. Results show that the full length of the CP genewas 858 nucleotides (nt). Comparison among CP genes of 16 PRV strains or isolates from Chinaand abroad indicated that Ys shared high CP gene homologous sequence (94.44%~97.68%)with the other strains or isolates from China, while it shared lower CP gene homologous sequence(88.88%-92.70% )with the strains or isolates abroad. It was noted that there were 6 nt missing after the 63rd nt in Ys CP gene, and there were 3 nt missing in CP genes of Sin. G. THAI.SRI. Ys CP cDNA was inserted into the cloning sites between CaMV 35S promoter and nos terminator of the middle plasmid pRok Ⅱ to produce the plant expression vector pRPCY. LBA44004of Agrtobacterium tumefasciens containing the binary vector system pRPCY/pAL4404 was obtained through triparental mating, and will be used to introduce CP gene into papaya genome.