RESEARCH
UNEARTHING KEYSTONE GENES IN FOREST ECOSYSTEMS
Microbial controls on forest productivity in a changing climate
CO2 is not only a major global pollutant contributing to climate change, but also alters the growth of forest trees. Forest productivity responses to increasing concentrations of CO2 are predicated on access to limiting soil nutrients, such as nitrogen and phosphorous. Working in Michigan, Alaska, and most recently, in Panama, I am investigating the role of ectomycorrhizal fungal symbionts in modulating past and future tree growth. Ectomycorrhizal fungal communities regulate access to soil nutrients, and I am employing molecular trait profiling of fungal communities paired with dendrochronological methods. This cross-biome work is aimed to elucidate molecular mechanisms of forest-microbe-soil interactions that determine the strength of the forest carbon sink and contribute to the parameterization of earth system models.
Functional ecology meets fungal genomics
I am interested in how fungal communities assemble and subsequently impact plant growth and soil nutrient cycling. Using metagenomic sequencing of fungal communities, I am investigating gene-based underpinnings of local adaptation in fungi, fungal competition, and consequences for plant resilience to climate stressors. I have completed work along soil nutrient gradients in Michigan, and am currently studying fungal traits conferring drought resistance along a drought stress gradient in the Pacific Northwest, and elevational gradients in Panama. Additional interests include the fungal and bacterial root and foliar endophytes
The population structure of mushrooms remains a relative mystery. Due to their small spores, and cryptic life-styles we know little about gene flow in fungi. To address such questions, we are studying Suillus pungens, a common ectomycorrhizal fungi endemic to Pine forests in California. Led by graduate student Jay Yeam, we have sampled mushrooms across California, as well as the Channel Islands. Using whole-genome sequencing, we are investigating dispersal limitation and genetic signatures of local adaptation.
Biogeography and diversity of fungal communities
New molecular methods designed for microorganisms provide unprecedented capacity to study classical questions in ecology. Working in collaboration with NSF’s NEON program, I am using a continental scale soil sampling network to probe the role of wind flow patterns in the diversity and composition of fungal communities. Because wind acts as a primary dispersal agent for the spores for mushroom forming fungi, this work expands understanding of dispersal limitation in fungal community assembly and spatiotemporal distributions of fungal communities. Future research will focus on investigating altered future wind flow regimes and their consequences for fungal community composition and function.
Fungal ecology and soil carbon storage
Fungal hyphae act as the primary decomposers in forest ecosystems by exuding powerful enzymes that degrade soil organic matter. Because soil carbon is one of the largest reservoirs of carbon on earth, understanding the role of fungi in soil carbon dynamics both present and future is essential for global carbon cycle modeling. My research broadly examines competitive interactions between saprotrophs and ectomycorrhizal fungi and their impact on soil carbon stocks.