Symbioses: Plant, Animal, and Microbe Interactions
Amend, Anthony , Yi, Cui , Fang, Zhendong , Keeley, Sterling C. .
Ainít No Mountain High Enough? Himalayan Topography Affects Gene Flow in a Prized Edible Mushroom.
Ectomycorrhizal symbiosis plays a fundamental role in forest ecology. Tricholoma matsutake, an edible and medicinal ectomycorrhizal mushroom, has been revered in Japan for centuries for its distinguished flavor, medicinal properties and iconic significance. Previous studies have demonstrated that this Asian species shows significant isolation by distance (IBD) population structure at scales ranging from continental to ~1,500 km. At shorter distances, however, this pattern attenuates. The main goal of this study was to determine what role topography plays in T. matsutakepopulation structure. Using multilocus single-nucleotide polymorphic DNA markers, IBD patterns were tested on populations within and among Himalayan valleys. We find that high ridgelines prove to be effective boundaries to gene flow, even at distances less than 50 km, whereas populations located within valleys rarely showed significant differentiation, even at distances up to 125 km. Mantel tests demonstrated a significant positive correlation between genetic and geographic distance between among-valley populations, but not for populations within valleys. AMOVA analysis revealed significant hierarchical variance partitioning with 95% of the genetic variance found within populations, and 5% found among valleys. Finally, we examined fine-scale population genetic structure of mycorrhizas in a human-disturbance chronosequence to infer how habitat affects reproductive strategy and dispersal. Small genet size and evidence for sexual recombination at small spatial scales throughout is indicative of prevalence of long-distance spore dispersal. This study systematically examines the fine scale population genetic structure of T. matsutake to test the effects of topography, distance and dispersal on population substructure. We show that the relationship between topography and gene flow is an important, if little studied, determinant of ectomycorrhizal population structure in three-dimensional landscapes. Implications for management of this economically important species are discussed.
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1 - University of Hawaii, Department of Botany, Manoa, Oahu, Hawaii, 96822, USA
2 - University of Michigan, Ann Arbor, MI, USA
3 - Shangrila Alpine Botanical Garden, Zhongdian, Yunnan, China
4 - University of Hawaii at Manoa, Department of Botany, 3190 Maile Way, Honolulu, HI, 96822, USA
isolation by distance
single nucleotide polymorphism.
Presentation Type: Oral Paper:Papers for Topics
Location: Blair A/Gage
Date: Tuesday, July 29th, 2008
Time: 10:45 AM