MSA - Systematics/Evolution
Stefani, Franck O.P. , Guillaumin, Jean-Jacques , Hamelin, Richard C. , Bérubé, Jean A. .
Multigene phylogeography and evolution of the phytopathogenic genus Armillaria.
The genus Armillaria comprises more than 40 species. Previous studies based on rDNA phylogeny provide limited information on phylogenetic relationships of Armillaria species from the Northern Hemisphere, and their historical biogeography remains unclear. We analyzed phylogenetic information from the ITS and nLSU rDNA regions and four nuclear coding genes (the actin (act) gene, the elongation factor 1 (EF1)-alpha (tef1) gene, the second largest subunit of RNA polymerase II (rpb2), and the glyceraldehyde 3-phosphate dehydrogenase (g3pd) gene) from 21 Armillaria biological species collected from North and South America, Europe, Africa, Asia and Oceania. Maximum parsimony, Bayesian inferences and molecular clock analyses were performed to resolve Armillaria phylogenetic relationships and phylogeographic evolution. The ITS and nLSU regions poorly made the distinction between inter- and intra-species, and left Armillaria species from the Northern Hemisphere unresolved. Combined coding genes phylogeny makes it possible to resolve Northern Hemisphere Armillaria species. It supports them as ancestral to southern species and considers that southern Armillaria species descended from A. mellea ss. str., a Northern Hemisphere species. The molecular clock analysis based on the 18S rDNA and actin coding gene considers the Armillaria species’ time divergence from the Agaricales to be between 23.7 and 38.6 MYA, respectively. This time divergence suggests a land migration from an East Asian centre of origin to be the main mechanism explaining the present day distribution of Armillaria species worldwide.
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1 - Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, Québec, Québec, G1V 4C7, Canada
2 - 63450 Chanonat, Jussat, France
3 - Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, Québec, Québec, G1V 4C7, Canada
Presentation Type: Poster:Posters for Topics
Location: Event Tent/Cliff Lodge
Date: Tuesday, July 28th, 2009
Time: 5:30 PM