|Lee, Ing Ming|
Submitted to: International Organization for Mycoplasmology
Publication Type: Abstract Only
Publication Acceptance Date: 4/6/2006
Publication Date: 7/7/2006
Citation: Davis, R.E., Jomantiene, R., Lee, I., Zhao, Y., Hammond, R., Shao, J.Y., Dally, E.L., Dawe, A., Davis, K., Nuss, D. 2006. Comparative genomics of 'candidatus phytoplasma asteris' and acholeplasma palmae: common ancestral genes lost during phytoplasma evolution. International Organization for Mycoplasmology.
Technical Abstract: Phytoplasmas and Acholeplasma spp. are wall-less bacteria that have small, AT-rich genomes and are classified, along with the genera Mycoplasma, Ureaplasma, Spiroplasma, Entomoplasma, and Mesoplasma, in class Mollicutes. Phylogenetic analyses based on ribosomal RNA have indicated that phytoplasmas descended from acholeplasma-like ancestors, but very little is known concerning genes that were lost and genes that were retained during the divergence of the phytoplasma clade and acholeplasmas from their last common ancestor (LCA). Whereas, phytoplasmas are obligately parasitic phytopathogens, known Acholeplasma spp. are apparently not obligate parasites and have not been described as phytopathogenic. Reconstruction of the LCA of phytoplasmas and Acholeplasma could aid understanding of both Acholeplasma and phytoplasma evolution. Thus far, two phytoplasma genomes have been completely sequenced, those of ‘Candidatus Phytoplasma asteris’-related strains OY-M and AY-WB, but no Acholeplasma genome has yet been sequenced. For a comparative genomics study of these three mollicutes, we initiated survey sequencing of the A. palmae genome. Results obtained thus far have revealed that A. palmae retained biosynthetic and degradative systems that were truncated, inactivated, or lost from the phytoplasma genomes after the phytoplasmas and acholeplasmas diverged. This presentation will focus on specific degradative systems.