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从我国北方地区呈现花叶症状的白草上分离得到1个白草花叶病毒分离物(AY642590,PenMV-B),测定了其RNA的核苷酸全序列。结果发现,该病毒分离物的RNA基因组全长共9 611个核苷酸,5′-末端和3′-末端的非翻译区序列分别为172和241个核苷酸,中间为9 198个核苷酸的开放读框,编码3 065个氨基酸,分子量约为349 575 Da;其多聚蛋白P3/6K1处的E/H蛋白切割位点序列与Potyvirus属其他病毒均不相同,为该病毒所仅有。预期的Potyvirus属病毒的一些重要的、功能性保守基序特征都存在于该病毒的基因组序列中。Potyvirus属病毒多聚蛋白氨基酸序列的系统进化树分析表明,PenMV-B和MDMV,SrMV,SCMV有较近的亲缘关系。根据ICTV最新的马铃薯Y病毒属分类标准,进一步确定该病毒具有Potyvirus属SCMV亚组新成员的分类地位。对SCMV亚组病毒和分离物基因组各区域的多重序列比较结果表明,PenMV在进化过程中有可能发生了基因的重组和变异。
A whitegrass mosaic virus isolate (AY642590, PenMV-B) was isolated from white grass showing mosaic symptoms in the northern part of China. The nucleotide sequence of its RNA was determined. The results showed that the total length of the RNA genome of this isolate was 9 611 nucleotides, with 172 and 241 nucleotides at the 5’-end and 3’-end and 9 198 nucleotides in the middle, respectively The open reading frame of the nucleotide encodes 3 065 amino acids and has a molecular weight of about 349 575 Da. The sequence of the E / H protein cleavage site at its P3 / 6K1 polyprotein is not the same as other viruses of Potyvirus. Only Some important, functional conserved motif features of the prospective Potyvirus are present in the genomic sequence of the virus. Phylogenetic tree analysis of the amino acid sequence of Potyvirus showed that PenMV-B had close genetic relationship with MDMV, SrMV and SCMV. According to the latest ICTV classification standard of potato virus Y, further identification of the virus as a new member of the subgroup of Potyvirus genus SCMV was conducted. Multiple sequence comparison of SCMV subgroups with isolates revealed that there may be some recombination and mutation of PenMV in the evolutionary process.