烟草脉带花叶病毒基因组序列分析

为了探明烟草脉带花叶病毒危害和流行的机制,使用RT-PCR技术扩增获得TVBMV云南分离物YN9.1基因组全序列,并进行了基因组结构、序列同源性、氨基酸保守基序、系统进化和重组分析。结果表明:(1)YN9.1基因组具有Potyvirus属病毒典型特征,含有在Potyvirus属病毒中较为少见的NIb/CP切割位点Q/N;(2)YN9.1与其它分离物核苷酸序列同源性为90.5-91.1%,氨基酸序列同源性为95.2-96.2%。与YND核苷酸和氨基酸序列同源性最高;(3)对HC-Pro和CP保守基序进行了分析。YN9.1具有RITC、PTK、DAG等病毒蚜虫传播保守基序,其中RITC在Potyvirus属病毒中常见形式为KITC;(4)系统进化树分析结果显示,TVBMV进化形成2个组,云南分离物独立进化形成一组,TVBMV进化与地域具有明显的相关性;(5)重组分析发现PY为ZC1和YN的组内重组体,重组位点位于HC-Pro 3'末端和NIb 5'端。 

Analysis of genomic sequence in tobacco vein banding mosaic virus

To gain insights into the damage mechanisms and prevalence of TVBMV, the complete genomic sequence of YN9.1 was determined by RT-PCR. The genome structure, sequence identity and similarity, conserved amino acid motif, phylogenetic and recombination analysis of YN9.1 were conducted. Results showed that (1)YN9.1 possessed typical genome characteristics of Potyvirus, and had a uncommon NIb/CP cleavage site of Q/N which was rare in potyviruses.(2)YN9.1 showed 90.5-91.1% nt and 95.2-96.2% aa identities with other TVBMV isolates, and shared the highest nt and aa sequence identity with YND. (3)Conserved motif in HC-Pro and CP of YN9.1 was analyzed, and the conserved motifs RITC、PTK and DAG were involved in aphid transmission. The motif RITC was the common form of KITC in Potyvirus.(4)Phylogenetic analysis showed that TVBMV isolates were divided into two evolutionary divergent groups, and isolates from Yunnan formed a separate branch, which revealed that TVBMV grouping was related to geographical origin. (5)The recombination analysis indicated that PY could be a intra-lineage recombinant, and had ZC1 as its major parents, and YN as its minor parent. The recombination sites were at the 3'end of HC-Pro and the 5'end of NIb.