大豆花叶病毒黄淮5号株系的基因组全序列分析

测定了大豆花叶病毒(SMV)我国黄淮5号(Y5)株系的基因组全序列.该病毒基因组全长9*!585个核苷酸,3′-末端具poly(A)尾,包含单一开放读码框,编码一个349.2kD的多聚蛋白.基因组全序列和美国SMV G2和G7株系的核苷酸同源性分别为97.4%和96.9%.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.Y5、G2和G7 3个株系的不同成熟蛋白间氨基酸序列的同源性为89.6%～100%.多重比较分析表明,Y5株系P1蛋白N-末端区域与G2和G7存在明显差异.进一步分析显示,这3个株系的6K1、6K2、NIa-Pro、NIa-VPg、NIb蛋白中心区域和CP蛋白高度保守,P1蛋白N-末端,CI和P3蛋白C-末端以及HC-Pro蛋白变异较大,但是美国G2和G7株系已报道序列P1蛋白区域存在可能的测序错误.

Biological Characterization and Sequence Analysis of Soybean Mosaic Virus of Chinese Huanghuai 5 Strain

The complete nucleotide sequecnce of the genomic RNA of Chinese strain Huanghuai 5(Y5) of soybean mosaic virus was determined.The genome was 9585 nucleotides long,excluding the 3'-terminal poly(A) tail A large open reading frame (nucleotide 133-9334) encoded a polyprotein of 3067 amino acids with a predicted molecular weight of 349 2kD There was 97 4% and 96 9% nucleotide identity over the entire genome with American strains G2 and G7 respectively Based on comparison with the proposed locations of cleavage sites of the other potyvirus polyproteins,10 mature proteins are predicted The mature proteins of Y5,G2 G7 strains shared 89 6% to 100% amino acid identities Nucleotide comparison demonstrated that N-terminal part of the P1 region was particularly variable,while substantially conserved regions occurred in the 6K1,6K2,NIa-Pro,NIa-VPgI and coat protein It seemed unlikely that differences in the NIa-Pro,NIa-VPg and CP proteins were responsible for virulence differences among these strains and the CI,HC-Pro,NIb and P1 regions were considered most promising for further study Subsequent analysis on P1 suggested some mistakes occurred in the published complete sequences of G2 and G7 strains from USA