Study on the Replicase Gene Structure of Potato Leafroll Virus Chinese Isolote
Abstract: According to the genomic sequence of PLRV S, two pairs of specific primers were designed and synthesized. The cDNA of the replicase gene of PLRV Chinese isolate (PLRV Ch) was synthesized and amplified by RT PCR using the viral RNA as a template. The synthesized 3 and 5 cDNA fragments of PLRV Ch replicase gene were inserted into pUC 19 and cloned in E.coli JM109 and sequenced respectively. The homology of nucleotide sequences between PLRV Ch and PLRV S (Scotland, UK), PLRV N (Netherlands), PLRV C (Canada), PLRV A (Australia) are 98.8%, 97.7%, 97.8% and 96.2%, and the homology of putative amino acid sequences are 98.9%, 97.4%, 97.6% and 95.8% respectively. In 5 region of replicase gene a slippery sequence (heptanucleotide motif) for 1 frameshift and its down stream stemloop or pseudoknot, and upstream nucleotide sequence repeats were found. Authors suggested that the nucleotide repeat sequences characteristic for PLRV could form a tight successively folded complementary double stranded re