Cloning and Molecular Taxonomy Analysis of 18S rRNA Gene of Cattle Theileria sergenti

To analyze 18S rRNA nucleotide sequence of cattle Theileria sergenti,two pairs of specific primers were deigned according to 18S rRNA gene of cattle Theileria sergenti sequences published on GenBank.18S rRNA gene was amplified by PCR and cloned into pMD18-T vector.Positive clones were identified by PCR screening and restriction digestion enzyme.The phylogenetic tree was inferred based on 18S rRNA sequence of Yanbian and the other eight species of Theileria available on GenBank.Sequencing of positive clones showed that the cloned gene has a total length of 1 744 bp.The phylogenetic tree indicated that Yanbian strain,Lanzhou strain,Japan strain of cattle T.sergenti were closer to China strain of T.buffili,but Yanbian strain was far from T.mutans.