大豆花叶病毒杭州分离物基因组全序列测定及其结构分析

Molecular Characterization of a Soybean Mosaic Virus Isolate from Hangzhou, China

测定了大豆花叶病毒杭州分离物(SMV-HZ)的基因组全序列.该病毒基因组全长9588个核苷酸,3'末端具poly(A)尾,包含单一开读框,编码一个350.07kD的多聚蛋白.基因组全序列与美国SMVG2、G7、N株系及我国黄淮5号株系(Y5)的核苷酸同一性分别为93%、93%、94%和96%.多聚蛋白酶解后产生马铃薯Y病毒属典型的10个成熟蛋白.SMV-HZ与G2、G7、N的不同成熟蛋白间的氨基酸同一性为89%～100%;SMV-HZ与Y5的不同成熟蛋白间氨基酸同一性则较高,达97%～100%.多重分析显示了SMV-HZ与G2、G7、N、Y5之间的序列差异,G2、G7的P1蛋白氨基酸序列明显不同于其他株系.对SMV-HZ与我国其他分离物也进行了序列比较,对CP蛋白氨基酸序列的系统进化树分析表明SMV-HZ与BJ分离物的亲缘性最高.

The complete nucleotide sequence of the genome RNA of SMV-HZ, a soybean mosaic virus isolate from Hangzhou, China was determined. The genome was 9588 nts long, excluding the 3'- terminal poly(A) tails. A large open reading frame (nucleotide 132-9332) encoded a polyprotein of 3067 amino acids with a predicted Mr of 350.07Kda. There was 93%, 93%, 94% and 96% nucleotide identity over the entire genome with SMV G2, G7 , N and Y5 respectively. Based on comparison with the proposed locations of cleavage sites of other potyvirus polyproteins, 10 mature proteins were predicted. The amino acid identities of the ten mature proteins between SMV-HZ and Y5 was 97%～100%, which was much higher than that between SMV-HZ and G2, G7, N. The latter varied from 89% to 100%. The detailed alignment with G2, G7, N and Y5 allowed the identification of the sequence difference and the similarity between the amino acid sequence of G2, G7 and other isolates was rather low. Sequences comparisons were also made between HZ and other Chinese isolates and the phylogenetic analysis of amino acid sequences of CP showed that HZ was most closely related to BJ, an isolate from Beijing, China.