Abstract: In order to understand the sequence characteristics, basic structure and genetic variation of P46 gene which was the main immunogenic surface membrane protein gene of local prevalent Mycoplasma hyopneumoniae (Mhp) strains in Guangxi Luchuan pig.The Mhp P46 gene in positive diseased swine samples which were collected from the purebred Luchuan pig farms in Guangxi from 2011 to 2013 was amplified using PCR,and then cloned into pMD18-T vector and transformed into E.coli DH5α.We chose the positive clones and sequenced.We amplified P46 genes of four positive strains (GXLC1,GXLC2,GXLC3 and GXLC4).Use the DNAStar software to analyse the cloned sequence.The results showed that P46 gene sequence was 1104 bp coding 368 amino acids.The sequence included three Trps coded by TGA codons which weren’t termination codons and one Arg coded by CGG codons which weren’t nonsense code.The homologies of nucleotide sequences of 4 strains were 98.4% to 99.4%,and the homologies of deduced amino acid sequences were 98.6% to 99.5% with these sequences of standard J strain,232 strain,7448 strain and 168 strain.The P46 genes of these strains had highly conservation because of the high-level homologies.

Key words: Guangxi Luchuan pig; Mycoplasma hyopneumoniae (Mhp); P46 gene; clone; sequence analysis