小西葫芦黄化花叶病毒分离物的3′末端序列多态性研究

Sequence Diversity of the 3′ End Genome for Zucchini Yellow Mosaic Virus Isolates

研究了来自中国大陆 9个小西葫芦黄化花叶病毒 (ZYMV)分离物的基因组 3′末端核苷酸序列及所推导的外壳蛋白 (CP)氨基酸序列以及 3′末端非编码区 (UTR)序列 ,并与其它地区所报道的 1 6个ZMYV分离物进行了同源性比较。ZYMVCP基因核苷酸序列具有一定的寄主相关性和地域相关性 ,但总体上其关联程度不明显 ;同时 ,CP氨基酸序列的寄主适应性程度明显高于地域相关性。 2 5个ZYMV分离物的CP氨基酸序列根据其变异程度分为 2个区 :N端约 41个氨基酸为高度变异区 ,CP核心区和C端氨基酸序列为保守区。研究结果初步揭示了ZYMV作为单链RNA病毒通过与寄主相互作用而表现寄主适应性变异的趋势。

The present study analyzed the 3′ end sequence of nine mainland isolates of Zucchini yellow mosaic virus (ZYMV) genome including the coat protein (CP) gene and 3′ end un-translated region (UTR). Obtained sequence data was compared with previously reported sequences of 16 ZYMV isolates from other regions of the world. In a certain degree, similarity of nucleic acid sequence for CP gene was found being related with the host origin and geological distribution, but not very obvious. Similarity of the CP amino acid sequences deduced from nucleic acid sequences of the 25 ZYMV isolates reached a higher sequence similarity and a clearer relationship to the host origins than to the geological distributions. According to its variation, the amino acid sequence of ZYMV CP was divided into two parts——“the high variable region” contains about 41 amino acids at its N end, while “the conservative region” includes CP core-region and C termini amino acids. Our results showed that the trend of ZYMV variation for its rapid adoption for fitness of the ecological condition, especially to host interaction by mutation of its genomic RNA.