Cloning of p80 gene in Indian isolates of Mycoplasma agalactiae

Contagious agalactia is one of the economically important diseases of small ruminants mainly caused by Mycoplasma agalactiae. Serological tests are considered to be the most suitable for screening the herds. But these tests have certain limitations due to the cross-reactive antigens among different Mycoplasma species and also these antigens are expressed with remarkable variability among M. agalactiae strains and isolates. Therefore, a good test should be based on an antigen that is M. agalactiae specific, expressed during the entire course of infection and all the field isolates. Thus, the present study was undertaken to amplify and clone the p80 gene of M. agalactiae for specific diagnosis of the disease. Four Indian isolates and one standard isolate of M. agalactiae were used in the study and tested for purity of the culture by cultural, biochemical tests, group specific and M. agalactiae specific PCR assays. The genespecific primers were self-designed and custom- synthesized for amplification of p80 which amplified the amplicon of 1014 bp from all the strains. Further, the amplified product was cloned in pGEM-T easy cloning vector, sequenced and analysed. The findings of present study indicated that the membrane protein p80 is conserved antigen among Indian isolates of M. agalactiae and can be used for specific diagnosis of contagious agalactia.