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Abstract Detail


Integrative species delimitation: incorporating multiple types of data

Grubisha, Lisa [1], Levsen, Nicholas [2], Olson, Matthew [2], Taylor, D. Lee [3].

Effectof host and geography on lineage divergence in the Populus-associated ectomycorrhizal fungus, Tricholoma populinum.

Species delimitation studies have largely focused on morphological similarities or phylogenetic inference or a combination of both types of data. Incorporation of additional forms of information to advance our understanding of what evolutionary and ecological factors influence species divergence are becoming more prevalent. Studies have shown that a single fungal species may have a great deal of molecular divergence while retaining morphological similarities resulting in many cryptic species that are often found in sympatry. The ectomycorrhizal fungus, Tricholoma populinum, forms obligate symbioses only with the genus Populus and is found in Europe and North America, providing an opportunity to assess the influence of geography and host to population structure and assess the presence of cryptic species. Bayesian analyses of sequences from five nuclear loci of Tricholoma populinum from Scandinavia associated with Populus tremula, and North America with P. balsamifera and P. trichocarpa, revealed genetically divergent lineages between continents. Estimates of divergence time revealed divergence of hosts P. tremula and P. balsamifera/P. trichocarpa occurred approximately 5 Ma which corresponds to the opening of the Bering Strait and prior to divergence of fungal lineages at approximately 1.7-1.0 Ma. Fungal divergence may have resulted from a single transoceanic founding event or allopatric isolation of T. populinum populations that was coincident with speciation of Populus hosts.Few records exist of T. populinum within the continental USA. That T.populinum occurs with two species of Populus found in very divergent lineages yet absent from Populus species more closely related to P. balsamifera/P. trichocarpa in the continental USA suggests the mid-latitude boreal-like environment may limit the range of this species in North America. Analyses of DNA sequences in conjunction with other data (host, geography, environment) provide insight to the evolutionary history and factors that affect speciation in ectomycorrhizal fungi.

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1 - Centre College, Biology , 600 West Walnut Street, Danville, KY, 40422, USA
2 - Texas Tech University, Biological Sciences, Lubbock, TX, 79409, USA
3 - University of Alaska, Institute of Arctic Biology, Fairbanks, AK, 99775, USA

Keywords:
species concept
plant-fungal interactions
mycology.

Presentation Type: Symposium or Colloquium Presentation
Session: C1
Location: Delaware C/Hyatt
Date: Monday, July 9th, 2012
Time: 10:45 AM
Number: C1006
Abstract ID:310


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