cDNA Cloning and Sequence Analysis of Genome Segment S7 of Rice Black-streaked Dwarf Virus
水稻黑条矮缩病毒基因组片段S7的cDNA克隆及全序列分析

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.