水稻矮缩病毒第一号组份基因和编码蛋白的序列分析

NUCLEOTIDE AND PROTEIN SEQUENCE ANALYSIS OF RICE DWARF VIRUS REPLICASE(SEGMENT S1)

水稻矮缩病毒（RiceDwarfVirus，简称RDV）是我国南方水稻病毒病的重要病原，属植物呼肠孤病毒。从中国福建分离物中克隆了基因组第一号片段（S1）的全长cDNA并对其进行全序列分析，结果表明RDV福建分离物S1克隆片段全长4422bp，含有一个长4332bp的开放阅读框架，编码一个由1444个氨基酸组成的多肽（P1），分子量为164kD．根据基因序列，对推测的P1氨基酸序列分析表明，序列中含有依赖于RNA的RNA聚合酶（RNA-dependentpolymerase-RDRP）保守序列：motifＩ（DXXXXD）、motifⅡ（SGXXXTXXXN）和motifⅢ（GDD），除此之外，在模式Ⅲ后还存在一个很保守的区域EXXKXY。由此说明RDVS1编码的蛋白P1可能是病毒的一种RDRP。将RDV福建分离物引核苷酸和编码蛋白氨基酸序列与日本流行株系相比，同源性分别为95％和97％。RDV福建分离物S1序列已被DenBank接受，号码为U73201。

The full length cDNA of Rice Dwarf Virus (RDV) Fuian isolato genome segment S1 was cloned and full length sequence was detendned.The results showed that S1 is 4422bP in length and contrins a major open reading hane which encedes a polypeptide with 1444 amino acids. The major ORF contains the RNA-dependent RNA polymerase (RDRP) consensus sequences,such as motif Ｉ (DXXXXD) motif Ⅱ (SGXXXTXXXN) and motif Ⅲ (GDD).In addihon to the three mohfs,a well-conserved region (EXXKXY) is found following motif Ⅲ. Therefore,we suggest that the protein encoded by S1 encodes the virus RDRP. Homology comparison of the nucleohde and amino acid sequences of the RDV Fuian isolate with the kn0wn sequences of the Japanese isolate showed that the b0th isolate have 95% and 97% on nucleohde and drino acid sequences, respechvely. The sequence data have been deP0sited with GenBank database under the accession no.U7320l.