烟草蚀纹病毒山东分离物全基因组序列的克隆和保守性分析

Sequence cloning and conservative analysis of the genomic RNAs of Tobacco etch virus SD1 isolate

为利用RNA介导的病毒抗性策略,培育抗性稳定或抗多烟草蚀纹病毒(Tobacco etch virus,TEV)株系的转基因植株,采用RT-PCR及5'-RACE方法克隆了烟草蚀纹病毒山东分离物TEV-SD1的全基因组序列。TEV-SD1全基因组核苷酸序列长度为9494 bp,包含1个9165 bp的开放阅读框架(open reading frame,ORF),编码3054个氨基酸。将TEV-SD1基因组序列与GenBank中已公布的4个TEV全基因组序列和11个外壳蛋白(coat protein,CP)基因序列比对分析发现,各分离物CP基因间的核苷酸和氨基酸序列平均相似性分别为96.65%和98.31%,高于其它功能基因间的相似性;各分离物CP基因3'端核苷酸序列相似性平均为96.55%,高于5'端序列。聚类分析发现TEV在自然界中的分子变异与其寄主关系密切。

In order to cultivate the stable or multi-resistant transgenic plants against Tobacco etch virus（TEV） isolates via the RNA-mediated virus resistance（RMVR）,the complete genomic sequence of TEV isolate from Shandong Province（TEV-SD1） was cloned by RT-PCR and 5′-RACE.The results indicated that the full-length of TEV-SD1 genome was 9494bp,containing a 9165bp length open reading frame（ORF） which encoded a polyprotein of 3054 amino acids.Compared the sequence of TEV-SD1 with four whole genomic sequences of TEV and 15 CP gene sequences of TEV which published in the GenBank,the average similarity of nucleotide and amino acid sequence of CP gene were 96.65% and 98.31%,respectively,higher than other functional genes of TEV;the average similarity of CP gene 3′-end sequence was 96.55%,higher than that of the 5′-end.Phylogenetic analysis showed that the molecular variation of TEV in nature was significant related with its host.The sequence conservative analysis is of great significance to guide the selection of target sequences for RNA interference（RNAi）.