甜菜花叶病毒新疆分离物基因组3'末端序列分析

甜菜花叶病毒（Beet mosaic virus，BtMV）属马铃薯Y病毒科、马铃薯Y病毒属，可经多种蚜虫以非持久性方式传播，病毒粒子为弯曲线状，核酸为单分子正义ssRNA。目前只有美国华盛顿分离物的全序列以及斯洛伐克和英国少数几个分离物3’端的部分序列被报道。美国分离物全长9591 nt，3’端具有PolyA尾，编码一个由3086个氨基酸组成的多聚蛋白，与其它Potyvirus病毒一样可切割成10个蛋白，从N到C端依次为P1、HC—Pro、P3、6K1、CI、6K2、NIa—Vpg、NIa～Pro、NIb和CP。对于我国发生的BtMV，1981年Liu等报道了发生于北京地区菠菜上的BtMV，之后研究人员相继报道了黑龙江、内蒙古和新疆等甜菜主产区甜菜花叶病的发生及危害情况，并陆续开展了对BtMV的生物学特性、外壳蛋白分子量测定和氨基酸组分分析、细胞病理学等研究，目前对于我国发生的BtMV的分子结构特征还未见报道。本文报道了甜菜花叶病毒新疆分离物（BtMV—XJ）3’端的核酸序列，并与国外已报道序列进行了比较分析，为从分子水平上明确我国BtMV的分子结构特点、深入研究其编码蛋白的功能打下了基础。

Sequence analysis of 3' terminal region of genome of Beet mosaic virus Xinjiang isolate

The 3' terminal genomic 1 611 nucleotides of Beet mosaic virus Xinjiang isolate (BtMV-XJ) from China was determined (GenBank accession number DQ345522). The sequence started within a single open reading frame which was expected to encode part C-terminus of NIb protein of 201 amino acids, complete cap-sid protein (CP) of 276 amino acids and followed by a 3' untranslated region (UTR) of 168 nucleotides. The comparison of sequence diversity among BtMV-XJ and other three previously reported isolates revealed that it shared 98.3%, 98.1%, 91.4% nucleotide identity, and 99.79%, 99.58%, 97.69% deduced aa sequence identity with the corresponding 3' terminal regions of BtMV-SL, BtMV-UK and BtMV-US, respectively, and that most nucleotide mutations were silent with no effect on aa sequence. In addition, a virus-specific and rapid RT-PCR detection method of BtMV was also developed based on the nucleotide sequence obtained.