西瓜花叶病毒2号新疆昌吉分离物外壳蛋白基因核苷酸序列分析

Nucleotide sequence analysis of coat protein gene of Watermelon mosaic virus 2 Xinjiang Changji isolates

利用RT-PCR从新疆昌吉地区表现花叶、疱斑、扭曲等症状的南瓜病株上检测到西瓜花叶病毒2号新疆昌吉分离物(简称WMV-2-XJ-CJ),并测定了该分离物外壳蛋白(CP)基因序列。序列分析表明,新疆昌吉分离物CP基因全长850个核苷酸,编码197个氨基酸。与国内外报道的12个WMV-2CP基因相比,其核苷酸序列同源性为92.6%～98.3%,由此推导的氨基酸序列同源性为94.7%～99.3%。新疆昌吉分离物在CPN′端可变区明显不同于国内外报道的核苷酸序列。WMV-2新疆昌吉分离物与日本和郑州分离物较其它国家和地区的分离物多出6个核苷酸,但其核苷酸及其推导的氨基酸序列差异较大。新疆昌吉分离物外壳蛋白有2个氨基酸残基明显不同于其它分离物,其中蚜传株系的特征结构域DAG突变为DAE。

WMV-2-XJ-CJ was detected by RT-PCR in infected leaves of pumpkin plant with mosaic,blister and distoreted symptom collected from Changji in Xinjiang. The coat protein gene of the isolate was sequenced. Sequence analysis showed that the complete CP gene of WMV-XJ-CJ had 850 nucleotide acids, coding 197 amino acids. When the obtained sequence data were compared with previously reported sequences of 12 WMV-2 isolates from the different regions,WMV-2-XJ-CJ shared identifies of 92.6% -98.3% in nucleotide acids and 94.7% -99.3% in amino acids deduced respectively. WMV-2-XJ-CJ had six nucleotide acids in N＇variable region of coat protein, similar as isolates from Zhengzhou and Japan,but different from the other isolates in nucleotide acids and amino acids obviously. The isolate had two amino acid residues obviously different from all other isolates, particularly the motif sequence associated with aphid transmission was changed from DAG into DAE.