Symbioses: Plant, Animal, and Microbe Interactions
Hopkins, Sarah E. , Taylor, D. Lee .
Fine-scale genetic structure is correlated with mycorrhizal specificity in Corallorhiza maculata, a non-photosynthetic orchid.
Corallorhiza maculata is a non-photosynthetic, highly selfing orchid that utilizes a fungal symbiont for all of its carbon requirements. Previous work based on three single nucleotide polymorphisms has provided evidence that there are at least six distinct genotypes and that each of these genotypes associates with a different, non-overlapping clade of fungi within the Russulaceae (PRSLB 271: 35-43. 2004). The aim of this study was to determine the strength of the original genotype classifications and to test whether the same patterns of fungal specificity hold when using more sensitive microsatellite markers. Primers for nine polymorphic microsatellite loci were developed for C. maculata. Between 3 and 20 individuals were collected from eleven populations of C. maculata sampled in Colorado and Wyoming. Sampled individuals were either in flower or had maturing capsules. The entire above-ground structure and a small piece of below-ground rhizome tissue were collected for each individual. The microsatellite markers were used on samples of plant tissue and fungal specific primers were used to amplify fungal ITS regions from orchid rhizome tissue. Individuals were assigned to populations/genetic lineages based on their microsatellite patterns using the program Structure. A tree was constructed with the fungal sequences and other representative species from the family Russulaceae. We found distinct orchid genotypes, each of which associated with its own clade of fungi within the Russulaceae, despite spatial proximity to other genotypes. This study provides further important evidence of the rapid and dynamic evolution of mycorrhizal specificity occurring in these model cheater orchids.
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1 - University of Alaska Fairbanks, Biology and Wildlife, 211 Irving I Building, Fairbanks, AK, 99775, USA
2 - University of Alaska, Institute of Arctic Biology, 311 Irving I Building, Fairbanks, AK, 99775, USA
Presentation Type: Poster:Posters for Topics
Location: Event Tent/Cliff Lodge
Date: Monday, July 27th, 2009
Time: 5:30 PM