水稻条叶枯病毒(RStV)基因组组分4的克隆与序列分析

利用RTPCR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pCRII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。

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

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 nucleotides 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.