My PhD work is focused on symbiotic interactions between land plants and soil fungi. Specifically, I am interested in the ectomycorrhizal symbiosis, an obligate, intimate mutualism between dominant woody plants in the temperate zones (Pinacea, Fagaceae, Salicaceae, etc.) and soil fungi in the Asco- and Basidiomycota. This relationship, in which plants trade fixed carbon (sugars) to the fungi in exchange for soil resources like nitrogen, has arisen dozens of times independently in the fungal lineages. I am interested in how this interaction functions on a physiological and genetic level, particularly with respect to compatibility between diverse plants and fungi, and how variation in symbiotic function across fungal lineages and environmental conditions contributes to the stability of the interaction over evolutionary time.
Plant-mediated partner discrimination in ectomycorrhizal mutualisms.
Although ectomycorrhizal fungi have well-recognized effects on ecological processes ranging from plant community dynamics to carbon cycling rates, it is unclear if plants are able to actively influence the structure of these fungal communities. To address this knowledge gap, we performed two complementary experiments to determine (1) whether ectomycorrhizal plants can discriminate among potential fungal partners, and (2) to what extent the plants might reward better mutualists. In experiment 1, split-root Larix occidentalis seedlings were inoculated with spores from three Suillus species (S. clintonianus, S. grisellus, and S. spectabilis). In experiment 2, we manipulated the symbiotic quality of Suillus brevipes isolates on split-root Pinus muricata seedlings by changing the nitrogen resources available, and used carbon-13 labeling to track host investment in fungi. In experiment 1, we found that hosts can discriminate in multi-species settings. The split-root seedlings inhibited colonization by S. spectabilis whenever another fungus was available, despite similar benefits from all three fungi. In experiment 2, we found that roots and fungi with greater nitrogen supplies received more plant carbon. Our results suggest that plants may be able to regulate this symbiosis at a relatively fine scale, and that this regulation can be integrated across spatially separated portions of a root system.
View details for PubMedID 30617861
Processes maintaining the coexistence of ectomycorrhizal fungi at a fine spatial scale
Biogeography of Mycorrhizal Symbiosis
edited by Tedersoo, L.
Springer. 2017: 79–105
View details for DOI 10.1007/978-3-319-56363-3_4
- Testing the co-invasion hypothesis: ectomycorrhizal fungal communities on Alnus glutinosa and Salix fragilis in New Zealand DIVERSITY AND DISTRIBUTIONS 2015; 21 (3): 268-278
- Interspecific mycorrhizal networks and non-networking hosts: exploring the ecology of the host genus Alnus Mycorrhizal Networks Springer. 2015
New wrinkles in an old paradigm: neighborhood effects can modify the structure and specificity of Alnus-associated ectomycorrhizal fungal communities
FEMS MICROBIOLOGY ECOLOGY
2013; 83 (3): 767-777
Host identity has been recognized as a key determinant of the structure of ectomycorrhizal (ECM) fungal communities, but the importance of neighboring ECM hosts is less well understood. To investigate the relative importance of host and neighborhood effects, we examined the ECM fungal communities associated with Alnus rhombifolia, a host of specific ECM fungi, and Betula occidentalis, a host of generalist ECM fungi. We hypothesized that the host-specific Alnus-associated ECM fungal community would not be susceptible to the influence of plant neighborhood, while the generalist Betula-associated community would. ECM fungal communities on both hosts were characterized using ITS sequences derived from conspecific and heterospecific host settings at a field site in western Idaho, USA, and from a growth chamber bioassay. In the field study, the Betula neighborhood added minor constituents to the Alnus ECM fungal community, while in the bioassay, late planting of Betula generated strong priority effects that allowed the established Alnus neighborhood to control the structure of the Betula community. Our results indicate that while host identity acts as a primary filter on the composition and diversity of ECM fungal communities, proximity to a closely related host can mediate significant changes in community structure.
View details for DOI 10.1111/1574-6941.12032
View details for Web of Science ID 000314474100021
View details for PubMedID 23078526