马铃薯卷叶病毒复制酶基因5'端克隆及序列分析

CLONING AND SEQUENCING OF THE REPLICASE GENE 5′ FRAGMENT OF POTATO LEAFROLL VIRUS-THE CHINESE ISOLATE

马铃薯卷叶病毒（Ｐｏｔａｔｏｌｅａｆｒｏｌｖｉｒｕｓ，ＰＬＲＶ）是正链ＲＮＡ病毒，属黄化病毒组（Ｌｕｔｅｏｖｉｒｕｓ）〔１〕，严格虫传，分布广泛，难以控制，侵染马铃薯能引起大面积减产，给马铃薯生产造成巨大损失。ＰＬＲＶ基因组全长６．０ｋｂ，有６个读...

According to the genomic sequence of PLRV-S, two specific primers were designed and synthesized. The cDNA of the 5′ 1248 nucleotides of replicase gene of PLRV Chinese isolate(PLRV-Ch)was synthesized and amplified by RT-PCR using the viral RNA as a template. The synthesized cDNA was inserted into pUC 19 and cloned in E. coli JM109. The full length of cDNA was sequenced. The homology of nucleotide sequence of 5′ 1.2 kb fragment of RdRp gene among PLRV-Ch and PLRV-S(Scotland, UK), PLRV-N(Netherlands), PLRV-C(Canada)and PLRV-A(Australia)are 98.3%, 97.1%, 97.6% and 96.4% and the homology of putative amino acid sequence are 98.3%, 96.7%, 96.6% and 94.2% respectively. Some characteristic sequences such as slippery sequence (heptanucleotide motif)for -1 frameshift and “stem-loop” or “pseudonot”, nucleotide sequence repeats and amino acid domain: motifⅠ, Ⅱ, Ⅲ and the basic amino acid sequence region in the N terminus of RNA-dependent RNA polymerase of PLRV were discussed. Authors suggest that the nucleotide repeat sequence characteristic for PLRV can form a successively folded complementary double stranded regions and hairpins. This structure possibly is related to -1 frameshift.