水稻黑条矮缩病毒基因组片段S7的cDNA克隆及全序列分析

应用RTPCR技术克隆了2个水稻黑条矮缩病毒 (rice blackstreaked dwarf virus,RBSDV)中国分离物，即浙江分离物和河北分离物的基因组片段S7，并测定了他们的全序列。结果表明：RBSDV浙江分离物(RBSDVZj)基因组片段S7全长2193nts(EMBL登录号为AJ297427)，RBSDV河北分离物基因组片段S7全长2190nts(EMBL登录号为AJ297428)，二者均含有两个开放阅读框(open reading frame,ORF)，分别编码约41kD和36kD多肽，2个中国分离物核苷酸同源性高达99%，相应的ORF编码的多肽同源性分别为100%和94.4%，与日本RBSDV基因组片段S7核苷酸同源性为93.4%和93.8%，相应ORF编码的多肽同源性分别为98.1%(ORF1)、96.5%和97.8%(ORF2)，与意大利MRDV S6核苷酸同源性为85.1%和85.3%，相应多肽同源性分别为92.3%(ORF1)、85.5%和86.8%(ORF2)。

cDNA Cloning and Sequence Analysis of Genome Segment S7 of Rice Black-streaked Dwarf Virus

Genome segments 7 of zhejiang and Hebei isolates of rice black-streaked dwarf virus (RBSDV) were amplified and sequenced.Segment 7 of Zhejiang isolate was consisted of 2193 nts (EMBL accession no. AJ297427) in length and that of Hebei isolate was 2190 nts (AJ297428).Both segments contained two non-overlapping open reading frames (ORFs), which encoded two polypeptides with molecular weights of 41 kD and 36 kD. These two segments shared 99% nucleotide identity, 100% and 94.4% amino acid identities of ORF1 and ORF2, shared 93.5% and 93.8% identities at nucleotide level, 98.1% (ORF1) and 96.5%/97.8% (ORF2) at amino acid level with S7 of Japanese RBSDV, and shared 85.1% and 85.3% identities at nucleotide level, 92.3% (ORF1), 85.5%/86.8% (ORF2) at amino acid level with S6 of Italian MRDV.