感染番茄抗病品种的番茄黄化曲叶病毒的基因变异分析

近几年来,生产中发现一些番茄抗病品种在不同环境条件下或应用几年后出现感病现象。为了解不同抗病品种中番茄黄化曲叶病毒(tomato yellow leafcurl virus,TYLCV)基因变异的情况,对5个感染TYLCV的番茄抗病品种进行了TYLCV全长基因克隆和序列测定。扩增结果显示,5个样品携带的TYLCV基因组长度均为2 781 bp,且均编码6个功能蛋白。基因组序列比较发现,这5个分离物与TYLCV-Israel株系同源性达到99%以上;通过功能蛋白比对发现,复制增强因子AC3蛋白存在变异,同世界各地报道的TYLCV-Israel株系典型分离物的AC3蛋白存在7处氨基酸差异的位点。分析结果表明,这五个病毒分离物均属于TYLCV-Israel株系,其AC3蛋白的氨基酸序列变异程度均不显著,并没有产生新的病毒株系。

Analysis of gene mutation of tomato yellow leaf curl virus infecting disease- resistant varieties of tomato

In recent years, some disease-resistant variety of tomatoes occur to be infected by Tomato yellow leafcurl virus (TYLCV) . In order to find out the mutation of the virus infecting disease-resistant tomatoes, the full-length gene sequences of five different TYLCV isolate from disease-resistant variety were cloned and sequenced. DNA sequence analysis showed that the genomes of virus isolate all contained 2781 bp nucleotides encoding six potential proteins and was most closely related to TYLCV-Israel strain (higher than 99% sequence identity) . Amino acid analysis based on the DNA sequence showed that AC3 protein has significant change and seven amino acid sites was found to be difference when compared with the representative isolates of TYLCV-Israel from different regions of the world. All the results showed that the five virus isolates all belonged to TYLCV-Israel strains. And the variation of AC3 proteins from the disease-resistant varieties of tomato was not significant that no new strain of virus were produced.