Submitted to: Avian Diseases
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/11/2003
Publication Date: 8/20/2003
Citation: BEARSON, S.M., COLLIER, S.D., BEARSON, B.L., BRANTON, S.L. INDUCTION OF A MYCOPLASMA GALLISEPTICUM PMGA GENE IN THE CHICKEN TRACHEAL RING ORGAN CULTURE MODEL. AVIAN DISEASES. 2003. v. 47. p. 745-749. Interpretive Summary: Mycoplasma gallisepticum remains a major obstacle for the poultry industry given that approximately 80% of commercial egg-laying chickens are infected. M. gallisepticum infections of layer flocks result not only in increased pharmaceutical costs and mortality but also decreased egg production at a potential annual financial loss of $118 million to the U.S. layer industry. Currently, research tools to investigate the respiratory disease caused by M. gallisepticum in poultry are limited. This study utilized two previously described techniques as a screening assay to identify M. gallisepticum genes involved in infection of the poultry respiratory tract. An M. gallisepticum bank containing 1,386 mutants was assembled and screened for gene expression activity in the presence of chicken tracheal cells. Eight of the M. gallisepticum mutants were found to have a two-fold or greater increase in gene expression activity. One of the genes identified encodes a protein involved in cell surface adhesion. M. gallisepticum genes identified in this assay may improve and/or develop vaccine strategies and infection control methods against poultry mycoplasmosis.
Technical Abstract: To search for Mycoplasma gallisepticum genes involved in colonization of the poultry respiratory tract, a transposon containing a promoterless lacZ gene was employed as a transcriptional reporter. The transposon was used to randomly mutagenize the chromosome of the M. gallisepticum S6 strain and a bank containing 1,386 transposon mutants was assembled. Each mycoplasma clone containing the lacZ reporter was independently screened in the chicken tracheal ring organ culture (TROC) model for increased production of b-galactosidase. A two-fold or greater increase in b-galactosidase was consistently observed for eight mutants. In one of the mutants, the transposon was inserted in a pMGA gene encoding a cell surface adhesin involved in hemagglutination. Therefore, this data indicates that screening of a M. gallisepticum transposon reporter bank using a chicken TROC model is useful for the identification of genes induced during poultry colonization and virulence.