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Our research is constantly evolving but take a look below to get a sense for major research themes and sources of funding.


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Biogeography & diversity of fungal communities

Until recently fungi and bacteria were thought to deviate from the fundamental biogeographic patterns found in plants and animals, such as the species-area relationship, geographic patterns of endemism, and the latitudinal gradient of species diversity. This thinking was based on assumptions about the large population sizes and potentially unlimited dispersal of microbes. We have investigated this paradigm using a number of different systems, ranging from host-specific mycorrhizal fungi on "tree islands" to continental and global scale surveys of fungal communities. Some common themes we investigate include, (i) what are the large-scale controls over fungal biodiversity, (ii) how do habitat size, isolation, and dispersal affect fungal community assembly, and (iii) how does climate influence the function of fungal communities? Some representative papers exploring these themes are below:

Steidinger BS, Bhatnagar JM, Vilgalys R, Taylor JW, Bruns TD, Peay KG (2020). Climate change will substantially alter continental diversity patterns of ectomycorrhizal fungi. Jouranl of Biogeography 47: 772-782

Smith GR, Steidinger BS, Bruns TD, Peay KG (2018) Competition-colonization tradeoffs structure fungal diversity. ISME Journal 12: 1758–1767

Talbot JM, Bruns TD, Taylor JW, Smith DP, Branco S, Glassman SI, Erlandson S, Vilgalys R, Liao HL, Smith ME, Peay KG. (2014) Endemism and functional convergence across the North American soil mycobiome. PNAS 111:6341-6346

Peay KG, Bruns TD, Kennedy PG, Bergemann SE, Garbelotto M (2007).  A strong species-area relationship for soil microbial eukaryotes:  Island size matters for ectomycorrhizal fungi.  Ecology Letters, 10:  470-480 

How do mycorrhizal mutualisms structure plant communities?

Interactions with symbiotic microbes, such as mycorrhizal fungi, have the potential to greatly influence plant growth, but it is unclear when field variation in symbiont availability and identity is sufficient to influence the outcome of plant community assembly.  We have used both observational and experimental approaches to understand the linkages between mycorrhizal fungi and plant communities. Some of the topics we have investigated include (i) understanding how the benefits of symbiosis change across environments, (ii) measuring the impact of mycorrhizal fungi on plant competition and community assembly, and (iii) investigating the genetic and environmental determinants of host specificity in plant-fungal interactions. You can see some of our recent findings in the area in these publications:

Bogar LM, Peay KG, Kornfeld, A, Huggins J, Hortal Sara, Anderson I, Kennedy PG. (2019). Plant-mediated partner discrimination in ectomycorrhizal mutualisms. Mycorrhiza29: 97-111

Van Nuland ME, Peay KG (2020) Symbiotic niche mapping reveals functional specialization by two ectomycorrhizal fungi that expands the host plant niche. Fungal Ecology 46: 100960

Duhamel MWan JBogar LMSegnitz RMDuncritts NEPeay KG (2019). Plant selection initiates alternative successional trajectories in the soil microbial community after disturbance. Ecological Monographs. 89: e01367

Peay KG (2018). Timing of mutualist arrival has a greater effect on Pinus muricata seedling growth than interspecific competition. Journal of Ecology106: 514-523

Diversity & ecology of tropical fungi

Global patterns of fungal biodiversity and their drivers are currently poorly understood.  One reason for this is the relatively small amount of research that has been done in southern hemisphere and tropical forests.  In addition to documenting community structure and diversity of fungi in tropical forests, we have worked on two larger ecological questions related to the role fungi play in shaping the diversity and composition of tropical tree communities. (i) Fungal pathogens have been hypothesized to regulate the commonness and rarity of tropical tree species. We are interested in understanding what structures host specificity in fungal pathogens and what host traits control tree susceptibility to fungal pathogens. (ii) While ectomycorrhizal fungi are thought to be important primarily in temperate, nitrogen-limited ecosystems, they can be common in certain biogeographic tropical regions (like Southeast Asia) or form anomalous monodominant tropical forest stands. We are interested in understanding the diversity of these ectomycorrhizal assemblages and how the affect dominance and habitat preferences of their hosts. A few representative papers from our work are below.

Segnitz RMS, Russo SE, Davies SJ, Peay KG (2020). Ectomycorrhizal fungi drive positive phylogenetic plant-soil feedbacks in a regionally dominant tropical plant family. Ecology 101: e03083

Peay KG, Russo SE, Mcguire K, Lim ZY, Chan JP, Tan S, Davies SJ (2015) Lack of host specificity leads to independent assortment of dipterocarps and ectomycorrhizal fungi across a soil fertility gradient. Ecology Letters 18:807-816 

Peay KG, Baroloto C, Fine PVA (2013) Strong coupling of plant and fungal community structure across western Amazonian rainforests. ISME Journal 7:1852-1861

Desjardin DE, Peay KG, Bruns TD. (2011). Spongiforma squarepantsii:  a new species of gasteroid bolete from Borneo. Mycologia. 103: 1119–23

Global change and fungi

Predicting the future of ecosystems under global change is a pressing challenge for all scientists. As major players in plant health and the carbon and nitrogen cycles, fungi will shape the trajectory of ecosystems as they respond to anthropogenic stressors. We have investigated fungal responses to a number of global change factors, including wildfires, nutrient deposition, warming soils, and changing precipitation regimes. A few papers illustrating our work in this area are below.

Smith GR, Edy LC, and Peay KG. (2021) Contrasting fungal responses to wildfire across different ecosystem types. Molecular Ecology 30:844-854.

Van Nuland ME, Smith DP, Bhatnagar JM, Stefanski A, Hobbie SE, Reich PB, Peay KG. (2020) Warming and disturbance alters soil microbiome diversity and function in a northern forest ecotone. FEMS Microbiology Ecology 96: fiaa108

Qin C, Zhu K, Chiarello NR, Field CB, Peay KG (2020) Fire history and plant composition outweigh decadal multi-factor global change as drivers of microbial composition in an annual grassland. Journal of Ecology 108: 611-65

Duhamel M, Wan J, Bogar LM, Segnitz RM, Duncritts NE, Peay KG (2019). Plant selection initiates alternative successional trajectories in the soil microbial community after disturbance. Ecological Monographs. 89: e01367

Funding Sources

Our research is generally funded through federal research grants. Below is a list of current and past grants.

2020-2024 National Science Foundation DEB-2021478. Defining the scope and consequences of ectomycorrhizal fungal control on forest organic matter decomposition. (with Peter Kennedy, Sarah Hobbie, Matthew Smith).

2020-2023 National Science Foundation DEB-1926335. Do defenses against herbivores and pathogens drive the commonness and rarity of tropical trees at local and regional scales? (with Paul Fine and Diego Amoretti).

2019-2024 National Science Foundation CAREER DEB-1845544. When do mycorrhizal fungi influence plant community dynamics? (sole PI).

2019-2022 National Science Foundation Macrosystems Biology DEB-1926335. Macroecology of microorganisms: Scaling fungal biodiversity from soil cores to the North American continent. (with Kai Zhu)  

2016-2021 Department of Energy Early Career Research Program DE-SC0016097. Does mycorrhizal symbiosis determine the climate niche for Populus as a bioenergy feedstock? (Sole PI) Award to Peay $750,208

2018-2019 Department of Energy Office of Biological & Environmental Research Cryo-electron microscopy and tomography for frozen, hydrated biological samples. (Lead PI Wah Chiu, with Co-PIs José Dinneny, Anne Sakdinawat, Michael Schmidt, Soichi Wakatsuki)

2018-2021 Department of Energy Joint Genomes Institute Community Science Program How does precipitation affect the taxonomic and functional diversity of the Populus trichocarpa soil microbiome.

2014-2017 Hoagland Award Fund for Innovations in Undergraduate Teaching The hidden kingdom: evolution, ecology & diversity of fungi.

2010-2015 National Science Foundation Dimensions of Biodiversity Program DBI 1046115. Deconstructing diversity and ecosystem function at multiple spatial and genetic scales in a keystone plant-microbe symbiosis. (with Thomas Bruns, Rytas Vilgalys, John Taylor). 

2011-2014 National Science Foundation Systematics and Biodiversity Science DEB-1119795 Building a molecular foundation for tropical mycorrhizal biology:  Sporocarp surveys of ectomycorrhizal fungal diversity of Southeast Asian dipterocarp forests. (with Krista McGuire)

2013-2015 National Science Foundation RAPID Program DEB 1361171. Do negative plant-soil feedbacks outweigh positive ectomycorrhizal mutualisms in dipterocarp rainforest?” (with Sabrina Russo)

2014-ongoing Department of Energy Joint Genomes Institute Community Science Program “Coprophilous fungi as a model system for understanding the metagenomics of carbon cycling in microbial eukaryote communities” (with Jason Stajich)