Expressed Sequence Tag (EST) survey of the highly adapted green algal parasite, Helicosporidium

Authors

• A. P. De Koning, University of British Columbia
• Aurelien Tartar, University of FloridaFollow
• Drion G. Boucias, University of Florida
• P. J. Keeling, University of British Columbia

Document Type

Article

Publication Title

Protist

ISSN

1434-4610

Publication Date

1-1-2005

Keywords

Green algae, Expressed Sequence Tag, Helicosporidia, Parasite, Phylogeny, Ribosomal protein, Entomopathogen

Abstract

Helicosporidia are obligate invertebrate pathogens with a unique and highly adapted mode of infection. The evolutionary history of Helicosporidia has been uncertain, but several recent molecular phylogenetic studies have shown an unexpectedly close relationship to green algae, and specifically to the opportunistic pathogen Prototheca. To date, molecular sequences from Helicosporidia are restricted to those genes used for phylogenetic reconstruction and genes related to the existence and function of its cryptic plastid. We have therefore conducted a small expressed sequence tag (EST) project on Helicosporidium sp., yielding about 700 unique sequences. We have examined the functional distribution of known genes, the distribution of EST abundance, and the prevalence of previously unknown gene sequences. To demonstrate the potential utility of large amounts of data, we have used ribosomal proteins to test whether the phylogenetic position of Helicosporidium inferred from a small number of genes is broadly supported by a large number of genes. We conducted phylogenetic analyses on 69 ribosomal proteins and found that 98% supported the green algal origin of Helicosporidia and 80% support a specific relationship with Prototheca. Overall, these data multiply the available molecular information from Helicosporidium 100-fold, which should provide the basis for new insights into these unusual but interesting parasites.

DOI

10.1016/j.protis.2005.02.005

Volume

156

Issue

2

First Page

181

Last Page

190

NSUWorks Citation

De Koning, A. P.; Aurelien Tartar; Drion G. Boucias; and P. J. Keeling. 2005. "Expressed Sequence Tag (EST) survey of the highly adapted green algal parasite, Helicosporidium." Protist 156, (2): 181-190. doi:10.1016/j.protis.2005.02.005.