Submitted to: International Organization for Mycoplasmology
Publication Type: Abstract Only
Publication Acceptance Date: March 2, 2004
Publication Date: July 11, 2004
Citation: Davis, R.E., Zhao, Y., Dally, E.L., Jomantiene, R., Shao, J.Y. 2004. Sequencing the genome of spiroplasma kunkelii genome: insights to a lifestyle of parasitism and pathogenicity in insects and plants. International Organization for Mycoplasmology. p. 63. Technical Abstract: Spiroplasmas are characteristically helical, motile prokaryotes that lack a cell wall. Taxonomically, these minute (0.15 to 0.2 um cell diameter and 2 to 10 um cell length) microbes are grouped with mycoplasmas of animals and man in class Mollicutes. First recognized in corn stunt diseased maize plants and insect vectors, spiroplasmas are now known from ticks and from numerous species of insects; some are found as epiphytes on aerial surfaces of plants; and some have been shown in laboratory studies to have pathogenic potential in vertebrate animals. We undertook to sequence the genome of Spiroplasma kunkelii, the causal agent of corn stunt disease, to gain insights into the genetic bases of spiroplasma parasitism and pathogenicity in plants and insect vectors. Sequences, from >9X sequencing coverage per base position of the ca. 1.6 Mb genome, were assembled into contigs available at http://www.genome.ou.edu/spiro.html. Features of the genome include genes homologous to genes in walled bacteria of the Bacillus/Clostridium group but apparently absent in Mycoplasma species; absence of cell wall biosynthesis genes found in the division/cell wall gene cluster of walled bacteria; numerous repeated sequences; genes encoding an abbreviated array of ABC transporters; potential protein coding regions (ORFs) encoding adhesin virulence factors; ORFs encoding putative proteins related to TypeIV secretion system elements involved in macromolecular transfer; and mobile genetic elements including spiroplasmavirus and plasmids. The genome sequence data provide clues to understanding evolutionary genome reduction in spiroplasmas, and the development of a spiroplasma genome approaching the minimal set of genes required for parasitism and pathogenicity in insect and plant hosts.