MSA - Systematics/Evolution
Sekimoto, Satoshi , Rochon, D’Ann , Dee, Jaclyn M. , Berbee, Mary L. .
A three-gene phylogeny of Olpidium (Chytridiomycota).
Most phylogenetic studies of fungi show that neither the chytrids nor zygomycote fungi are monophyletic. Branching order of deep nodes among these taxa remains mostly unresolved. Surprisingly, recent molecular data from nuclear ribosomal DNA and RPB1 placed the unicellular endoparasitic chytrid Olpidium brassicae among the zygomycote fungi, although without significant statistical support. In this study, we test the phylogenetic position of two plant parasitic Olpidium species, adding new protein-coding gene data. We sequenced and analyzed elongation factor 2 (EF-2) and two RNA polymerase II subunits (RPB1 & RPB2) genes of chytrid and zygomycote fungi representing major lineages of both groups. Each individual gene tree showed that Olpidium formed a clade with Zygomycota group 2 (a group including all zygomycote orders except Mucorales, Endogonales, and Mortierellales) although still without bootstrap support. By concatenating the three genes, maximum likelihood analysis provided robust support for the monophyly of Olpidium with all terrestrial (non-flagellated) fungi. Tests of alternative tree topologies ruled out monophyly of the Olpidium species with the other main groups of flagellated fungi. These results clearly suggest that Olpidium is related to terrestrial fungi rather than to other chytrids, and terrestrial fungi evolved more than once through flagellum loss and evolution of hyphal habit.
Log in to add this item to your schedule
Assembling the Fungal Tree of Life (AFTOL) web site
1 - University of British Columbia, Department of Botany, 3529-6270 University Boulevard, Vancouver, BC, V6T 1Z4, Canada
2 - Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, P.O. Box 5000, Summerland, BC, V0H 1Z0 , Canada
Presentation Type: Oral Paper:Papers for Topics
Location: Cottonwood A/Snowbird Center
Date: Tuesday, July 28th, 2009
Time: 8:45 AM