【摘要】 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。更多还原

【Abstract】 One potyvirus isolated from perennial whitegrass (Pennisetum centrasiaticum Tzvel) in North China was characterized at the molecular level.The complete nucleotide (nt) sequence of this virus(AY642590) has been determined.The viral genome comprised 9611 nt excluding a 3′-terminal poly (A) sequence,encoded a single polyprotein of 3 065 amino acids with a calculated Mr of 349 575 Da,flanked by 5′ and 3′-NTRs with 172 and 244 nucleotides.Nine putative cleavage sites were found by a sequence comparison of the viral polyprotein with other potyviruses.The result showed that the putative cleavage site for this virus was E/H between P3 and 6K1,different from that of any other potyviruses.Sequence comparison of the amino acids of CP and the 3′ NTRs showed that this virus was most closely related to Pennisetum mosaic virus (PenMV) with percent identities of \{98.3%\} and \{99.2%\} respectively.Sequence comparisons and phylogenetic analysis of the complete nucleotides and amino acids suggested that the virus isolate was most closely related to the monocot Potyvirus like Sorghum mosaic virus (SrMV),Sugarcane mosaic virus (SCMV) and Maize dwarf mosaic virus (MDMV),Sequence comparison and phylogenetic analysis confirmed our previous report that PenMV was a distinct potyvirus within the SCMV subgroup,it also showed that there was a possible recombination during the evolution of viral genomes by sequence comparison and phylogenetic analysis of the complete and partial nucleotides.更多还原