Molecular Variability of House Finch Mycoplasma gallisepticum Isolates as Revealed by Sequencing and Restriction Fragment Length Polymorphism Analysis of the pvpA Gene

• Published in: Avian diseases 2003-07, Vol.47 (3), p.640-648
• Main Authors: Pillai, SR, Mays, H L, Ley, D H, Luttrell, P, Panangala, V S, Farmer, K L, Roberts, SR
• Format: Article
• Language: English
• Subjects: Carpodacus mexicanus; Mycoplasma gallisepticum
• ISSN: 0005-2086
• DOI: 10.1043/0005-2086(2003)047(0640:MVOHFM)2.0.CO;2

Mycoplasma gallisepticum, a major pathogen of chickens and turkeys, has caused significant declines in house finch (Carpodacus mexicanus) populations in the eastern United States since it was first observed in this species in 1994. There is evidence that M. gallisepticum infection is now endemic among eastern house finches, although disease prevalence has declined, suggesting an evolving host-parasite relationship. Studies based on randomly amplified polymorphic DNA (RAPD) have documented the presence of a single, unique RAPD profile in house finch M. gallisepticum isolates, suggesting a single point source of origin, which agrees with the known epidemiologic observations. In the present study, we evaluated the molecular variability of 55 house finch isolates as well as 11 chicken and turkey isolates including reference strains of M. gallisepticum. Molecular variability was evaluated by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) analysis and nucleotide sequencing of the pvp A gene, which encodes for the putative cytadhesin protein PvpA. Three different RFLP groups and 16 genotypes were evident from the 55 house finch isolates evaluated. Sequence analysis of pvp A gene PCR products showed that although most house finch M. gallisepticum isolates clustered more closely to each other, others clustered more closely to either turkey or chicken field isolates. These findings suggest that house finch isolates are more polymorphic than previously recognized by RAPD studies. This feature may allow us to learn more about the molecular evolution and epidemiology of this emerging disease host-parasite relationship.Original Abstract: Variabilidad molecular de aislamientos de Mycoplasma gallisepticum provenientes de pinzones o camachuelos de Mexico revelada mediante la secuenciacion y el analisis de la longitud de los fragmentos de restriccion del gen pvpA. eta l Mycoplasma gallisepticum, el principal patogeno de pollos y pavos, ha ocasionado una disminucion significativa en las poblaciones de pinzones o camachuelos de Mexico (Carpodacus mexicanus) en el este de los Estados Unidos desde que fue observada por primera vez en esta especie en 1994. Existe evidencia de que la infeccion por M. gallisepticum es actualmente endemica en el este de los Estados Unidos, aunque la prevalencia de la enfermedad ha disminuido, sugiriendo una evolucion en la relacion huesped-parasito. Los estudios basados en los fragmentos polimorficos de ADN amplific