Mycoplasma gallisepticum

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A Microbial Biorealm page on the genus Mycoplasma gallisepticum


Higher order taxa

Bacteria; Firmicutes; Mollicutes; Mycoplasmatales; Mycoplasmataceae; Mycoplasma; gallisepticum


NCBI: Taxonomy

Genus species

Description and significance

  M. gallisepticum is a bacterial pathogen that results in chronic respiratory disease.  

It is found in the respiratory system of poultry and other avian species at a temperature of 37°C. The pathogen lacks a cell wall, has a flask-shaped appearance, blebs at the poles of the cell and specialized tip-like organelles. Depending on the environment, M. gallisepticum can survive from a few days to months. On cotton, rubber, hair and feathers, M. gallisepticum can survive between one and four days. In dry conditions at 4°C it can survive 61 days and at 20°C, survive 10 to 14 days. The sequencing of the genome was to determine the pathogenic mechanism of virulence of the bacterium. A clone of the genomic strain Rlow designated Rlowc2 (isolated from the respiratory system of chickens and the respiratory organs, eyes and brains of avian species) was used to sequence the genome of M. gallisepticum.

Genome structure

The circular DNA genome of M. gallisepticum is 996,422 bp long with a G+C content of 31mol%. 742 coding DNA sequences (CDSs), 91% coding density, have been determined of the 996,422 bp. Of the 742 CDSs, functions of 469 coding DNA sequences have been determined, 159 CDSs are conserved hypothetical proteins and the remaining 123 CDSs are hypothetical proteins. Breakdown of the 742 coding DNA sequences can be seen in Table 1. 33 tRNA genes were identified in the genome along with a polypeptide release factor prfA (similar to DNA transcription UAA and UAG stop codons). M. gallisepticum genome contains two 16s rRNA genes.

Like M. pneumoniae and M. genitalium, M. gallisepticum’s genes within the OriC region are not conserved. Genes in the OriC region include: gyrA, gyrB, dnaJ, dnaN, soj (upstream of dnaA), and ABC transporters, rpl34 and rpnA (downstream of dnaA). The origin of replication contains an increased number of A•T base pairs (characteristic of prokaryotes) found between the dnaN and soj genes.

The genome of M. gallisepticum contains genes, including VlhA, also known as pMGA lipoproteins, that make up the largest family of genes. This family is noted as the vlhA family that generates an antigenic variation in chickens and avian species, important in allowing the bacteria to evade the hosts’ immune response. The vlhA family consists of 43 genes making up a total 43kb of the bacterial genome.

Cell structure and metabolism

Describe any interesting features and/or cell structures; how it gains energy; what important molecules it produces.


Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc.


How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.

Application to Biotechnology

Does this organism produce any useful compounds or enzymes? What are they and how are they used?

Current Research

Enter summaries of the most recent research here--at least three required


[Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.

Edited by Tawny Issarapanichkit, student of Rachel Larsen and Kit Pogliano