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本文将黄瓜花叶病毒CMV-BG株系侵染普通烟草的不同单株后,放在不同温度下培养,30d后对接种植株症状进行对比观察,并对2b基因表达进行了检测及其序列测定分析。结果表明:被CMV-BG株系侵染的植株在低温条件下,植株新生的大部分叶片严重畸形,而CMV-BG株系2b基因的表达与不同温度条件没有相关性;CMV2b基因序列与源分离物CMV-BG序列相比发生了较明显的变异,它们作为一组序列与分离物SF/GF/SY等的相似性甚至高于源BG序列;此外,尽管来自2组植物中的病毒序列变化均未表现正选择(positive selection),但来自低温培养的侵染植株的2b基因的多态性明显高于常温条件培养的植株,发生非同义突变的位点数目也高于同义突变的位点数目。因此认为,低温有助于加强CMV-BG株系2b基因的多态性。
In this paper, CMV-BG lines of cucumber mosaic virus infected different plants of Nicotiana tabacum and then cultured at different temperatures. After 30 days, the symptoms of inoculated plants were compared and the 2b gene expression was detected and sequenced analysis. The results showed that most of the leaves of plants infected with CMV-BG were severe deformities at low temperature, while the expression of 2b gene in CMV-BG lines had no correlation with different temperature conditions. The sequence of CMV2b gene and source Compared with the CMV-BG sequences of the isolates, significant differences were observed in the sequences. The similarity between the CMV-BG sequences and isolates SF / GF / SY was even higher than that of the source BG sequences. In addition, The positive selection did not show any positive selection, but the polymorphism of the 2b gene from the infected plants at low temperature was significantly higher than that at room temperature. The number of non-synonymous mutation sites was also higher than the synonymous mutation The number of sites. Therefore, it is considered that hypothermia helps to enhance the polymorphism of 2b gene in CMV-BG strain.