牛泰勒虫18S rRNA基因序列比较研究

Studies on Comparison of 18S rRNA Gene Sequences of Theileria Species Infective to Cattle

作者对中国兽医微生物菌种保藏中心原虫资源库内收藏的3种牛源泰勒虫10个地方分离株（包括4株环形泰勒虫、3株瑟氏泰勒虫和3株中华泰勒虫）的18S rRNA基因序列进行了测定，并用所测得的牛的泰勒虫中国株基因序列和自GenBank下载的各种泰勒虫18S rRNA基因序列构建了系统发生树。结果显示：牛的3种泰勒虫18S rRNA基因大小在1740-1890 bp，并有规律地分布于3个不同的进化枝上，且种内地方分离株之间的同源性明显大于种间同源性，说明采用18S rRNA基因序列测定方法对牛的泰勒虫进行分类与传统分类方法具有较好的符合性。该研究也可为建立针对18S rRNA基因为靶标的牛的泰勒虫病PCR检测方法奠定基础。

Ribosomal small-subunit RNA gene sequence of ten Chinese Theileria strains infective to cattle, including four isolates of Theileria annulata, three isolates of T. sergenti and three isolates of T. sinensis, collected in the protozoon resource library at the center-conservation of strain in China veterinary microbion, were cloned and analyzed and then the phylogenetic trees were constructed based on 18S rRNA sequence of the Chinese isolates as well as other species of Theileria available in GenBank. The result indicated that the length of the 18S rRNA gene of all Theileria species involved in this study were varied between 1 740--1 890 bp and Chinese isolates of three Theileria isolates were located in the different phylogenetic branch, moreover, the percent identities of the different isolates in species were much higher than among species. The results were basically consistent with traditional classification as well as molecular classification based on 18S rRNA gene sequence for the bovine Theileria. This study will provide a foundation for PCR detected method for bovine theileriosis.