不同来源的柑橘衰退病毒分离物基因组5′端A、F变异区序列克隆及分析

Cloning and analyzing of 5′ A and F variation sequences of Citrus tristeza virus genomic RNA of isolates from different regions

柑橘衰退病毒(Citrus tristeza virus,CTV)组群自然条件下存在株系分化现象。本研究利用RT-PCR技术扩增、克隆了来自我国不同地区的21个柑橘衰退病毒分离物的5′端A、F变异区。通过分析发现,不同来源的各分离物在5′端A、F区存在较大的变异。21个分离物A区序列相似性最低为85.8%,最高可达99.8%,平均为95.9%;与GenBank中9个代表性株系的平均相似性为84.2%。F区序列相似性较A区高,为98.0%;相似性最低为94.3%,最高达99.1%。结果显示不同来源的CTV分离物5′端序列A、F区变异较大。

Population structure and genetic variation of Citrus tristeza virus （CTV） were existing naturally. In the study, RT-PCR protocol was used for amplification and cloning of 5＇ A and F variation sequences of 21 isolates. The result showed that 5＇ A and F region had varied largely. The average sequence similarity within 21 isolates was 95.9% ; the lowest was 85.8% and the highest was 99.8%. The average sequence similarity between 21 isolates and 9 representatives in GenBank was 84.2%. The sequence similarity in F region was 98.0%, higher than in A region. The lowest sequence similarity was 94.3%, and the highest was 99.1%. The result revealed the fact that great genetic variation occurred in 5＇ A and F region.