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Data from: Population structure of mountain pine beetle symbiont Leptographium longiclavatum and the implication on the multipartite beetle-fungi relationships
Tsui, Clement Kin-Ming; Farfan, Lina; Roe, Amanda D.; Rice, Adrianne V.; Cooke, Janice E. K.; El-Kassaby, Yousry A.; Hamelin, Richard C. — 2015-06-17 Over 18 million ha of forests have been destroyed in the past decade in Canada by the mountain pine beetle (MPB) and its fungal symbionts. Understanding their population dynamics is critical to improving modeling of beetle epidemics and providing potential clues to predict population expansion. Leptographium longiclavatum and Grosmannia clavigera are fungal symbionts of MPB that aid the beetle to colonize and kill their pine hosts. We investigated the genetic structure and demographic expansion of L. longiclavatum in populations established within the historic distribution range and in the newly colonized regions. We identified three genetic clusters/populations that coincide with independent geographic locations. The genetic profiles of the recently established populations in northern British Columbia (BC) and Alberta suggest that they originated from central and southern BC. Approximate Bayesian Computation supports the scenario that this recent expansion represents an admixture of individuals originating from BC and the Rocky Mountains. Highly significant correlations were found among genetic distance matrices of L. longiclavatum, G. clavigera, and MPB. This highlights the concordance of demographic processes in these interacting organisms sharing a highly specialized niche and supports the hypothesis of long-term multipartite beetle-fungus co-evolutionary history and mutualistic relationships.
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Data from: Comparative phylogeography, genetic differentiation, and contrasting reproductive modes in three fungal symbionts of a multipartite bark beetle symbiosis
Roe, Amanda D.; Rice, Adrianne V.; Coltman, David W.; Cooke, Janice E. K.; Sperling, Felix A. H. — 2010-11-08 Multipartite symbioses are complex symbiotic relationships involving multiple interacting partners. These types of partnerships provide excellent opportunities in which to apply a comparative approach to identify common historical patterns of population differentiation and species-specific life history traits. Using three symbiotic blue stain fungal species (Ophiostomatacea) associated with outbreaking populations of the mountain pine beetle (Dendroctonus ponderosae Hopkins) in western Canada, we applied phylogenetic, population genetic, and demographic approaches to clarify phylogeographic patterns among the three fungal species. Broadly, the three species showed significant population differentiation, forming northern and southern populations, despite dramatic differences in haplotype diversity. Finer scale structuring and population demographic patterns were less consistent, showing some interspecific incongruence. By contrasting these species simultaneously, we were able to identify differences in recombination rate and ecological traits that can explain the observed patterns of incongruence among the fungal species. By applying a comparative approach to partners of a multipartite symbiosis we were able to distinguish congruent population structuring and species-specific differences that help us to understand the complexity and evolution of this symbiotic system.
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Data from: Population structure and migration pattern of a conifer pathogen, Grosmannia clavigera, as influenced by its symbiont the mountain pine beetle
Dryad
Tsui, Clement Kin Ming; Roe, Amanda D.; El-Kassaby, Yousry A.; Rice, Adrianne V.; Massoumi Alamouti, Sepideh; Sperling, Felix A. H.; Cooke, Janice E. K.; Bohlmann, Jörg; Hamelin, Richard C. — 2011-09-13 We investigated the population structure of Grosmannia clavigera (Gc), a fungal symbiont of the mountain pine beetle (MPB) that plays a crucial role in the establishment and reproductive success of this pathogen. This insect–fungal complex has destroyed over 16 million ha of lodgepole pine forests in Canada, the largest MPB epidemic in recorded history. During this current epidemic, MPB has expanded its range beyond historically recorded boundaries, both northward and eastward, and has now reached the jack pine of Alberta, potentially threatening the Canadian boreal forest. To better understand the dynamics between the beetle and its fungal symbiont, we sampled 19 populations in western North America and genotyped individuals from these populations with eight microsatellite markers. The fungus displayed high haplotype diversity, with over 250 unique haplotypes observed in 335 single spore isolates. Linkage equilibria in 13 of the 19 populations suggested that the fungus reproduces sexually. Bayesian clustering and distance analyses identified four genetic clusters that corresponded to four major geographical regions, which suggested that the epidemic arose from multiple geographical sources. A genetic cluster north of the Rocky Mountains, where the MPB has recently become established, experienced a population bottleneck, probably as a result of the recent range expansion. The two genetic clusters located north and west of the Rocky Mountains contained many fungal isolates admixed from all populations, possibly due to the massive movement of MPB during the epidemic. The general agreement in north–south differentiation of MPB and G. clavigera populations points to the fungal pathogen’s dependence on the movement of its insect vector. In addition, the patterns of diversity and the individual assignment tests of the fungal associate suggest that migration across the Rocky Mountains occurred via a northeastern corridor, in accordance with meteorological patterns and observation of MPB movement data. Our results highlight the potential of this pathogen for both expansion and sexual reproduction, and also identify some possible barriers to gene flow. Understanding the ecological and evolutionary dynamics of this fungus–beetle association is important for the modelling and prediction of MPB epidemics.

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(source : Dryad) AND (auteur : Rice, Adrianne V.)

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