水稻条叶枯病毒(RStV)基因组组分4的克隆与序列分析

CLONING AND SEQUENCING ANALYSIS OF RICE STRIPE VIRUS GENOME SEGMENT 4 OF CHINESE ISOLATE Y *

利用ＲＴＰＣＲ技术合成并扩增了水稻条叶枯病毒（ＲＳｔＶ）中国云南分离物基因组组分４的全长ｃＤＮＡ，将ＰＣＲ产物克隆在载体ｐＣＲＩ上，并进行全序列测定，所得核苷酸序列及推测的氨基酸序列与日本分离物Ｔ进行比较。结果表明，在核苷酸水平，两分离物的ｖＯＲＦ、ｖｃＯＲＦ及基因间非编码区序列的同源性分别为９４９％、９４１％、８６１％，５’端非编码区序列相同，而３’非编码区同源性为９６１％，仅有两个核苷酸不同；在氨基酸水平，ｖＯＲＦ及ｖｃＯＲＦ编码蛋白的同源性分别为９９４％和９８３％。可见，编码区的大小及其氨基酸序列和两末端序列都是很保守的。因此，中国云南分离物Ｙ与日本分离物Ｔ可能有很近的亲缘关系。

The cDNA fragment covering full length sequence of RStV RNA4 of Yunnan isolate in China was obtained by RT PCR.The PCR derived fragment was then cloned into vector pCRII.The cloned cDNA was sequenced.Comparison of the nucleotide and deduced amino acid sequences with those of the Japanese isolate T was made.The results showed that at the nucleotidt level,vORF,vcORF and the intergenic region had 94 9%,94 1% and 86 1% identity respectively,the 5′ untranslational region was exactly the same as that of Japanese isolate T,while the 3′ terminal sequence had 96 1% identity,differing by two nucleotides;at the amino acid level,vORF and vcORF had 99 4% and 98 3% identity respectively.Therefore,as well as being exactly the same size for the two isolates,the amino acid sequences of the coding regions and the 5′ and 3′ terminal sequences were well conserved.Our results indicated that the Chinese isolate is closely related to the Japanese isolate T.