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Ectomycorrhizal Host Specificity

We (Peter and Nhu) have teamed up with Rytas Vilgalys and Sunny Liao to more deeply probe the genomic underpinnings of ectomycorrhizal host specificity using the genus Suillus as a model system. Across our labs, we will doing a series of inoculation trials of 'matched' and 'mismatched' host-ECM fungus pairings to better understand and define the molecular cross-talk controlling ectomycorrhizal root tip colonization. As part of this project, we will also be sequencing many additional Suillus genomes to finally resolve the deep nodes in the Suillus tree.

Complementary to this work, Lotus Lofgren is focusing her dissertation research on a curious Suillus species, S. subaureus. This species appears to have jumped from conifers onto angiosperm hosts (check out Lotus and her co-author team at ICOM presenting her preliminary results) and Lotus is studying its ecology and genomics (thanks JGI for the support with generating a S. subaureus genome!). We would love assistance obtaining collections of fresh specimens of S. subaureus and are happy to pay for shipping to Minnesota. Check out our 'wanted' flyer - please feel free to pass onto others who might be out collecting.

Interguild Fungal Interactions

With the rise of high-throughput sequencing techniques, the ability to analyze the interactions among different fungal guilds has been greatly enhanced.  We have built some bioinformatic tools to help parse high-throughput fungal datasets by ecological guild and have recently teamed up with Jonathan Schilling to examine the microbial 'handoffs' between endophytic fungi and wood decay fungi in decomposing boreal forest birch logs. Lauren Cline led the data generation  and writing push for this project - see a pic of the field work here. Parallel work on this 'handoff' in a lab setting was also done in collaboration with Jonathan Schilling and Zewei Song.

Ectomycorrhizal Competitive Dynamics

Significant progress has been made in recent years understanding the influence of interspecific interactions on the structure of ectomycorrhizal fungal communities (click here for a review on the topic). We maintain an active interest in studying ectomycorrhizal competition - see recent lab publications on vertical niche partitioning among ectomycorrhizal fungi (suggesting competition is important) and co-occurrence patterns in Alnus forests (suggesting competition is largely absent). We (Peter and Julia) have also teamed with Sara Hortal and Ian Anderson at the Australian Hawkesbury Institute for the Environment to study the interactions among Suillus species that colonize the host genus Larix. This experiment used a split-root approach to test the extent of partner discrimination in ectomycorrhizal symbioses.  That work has now grown to include an exciting collaboration with Laura Bogar, a former undergraduate student at Lewis & Clark and current Ph.D. student in Peay lab at Stanford University. 

Carbon Cycling & Mycorrhizal Fungi

We (Chris and Peter) are currently conducting two experiments examining the role of mycorrhizal fungi in ecosystem carbon cycling.  One of the projects is based at Cedar Creek Ecosystem Science Reserve and focuses on testing the influence of host tree composition on the direction and magnitude of the 'Gadgil Effect' (see Chris checking out one of the fruitbodies present in one of his plots).  Our results suggest that responses are strongly dependent of host tree composition, which has important implications for forest soil carbon cycling modelling efforts (i.e. the 'Gadgil effect' is not everywhere).  We are also working in the DOE-funded S.P.R.U.C.E. project examining the decomposition of mycorrhizal fungal necromass. This work is a collaborative project with researchers at the University of Olso and the Norwegian Life Sciences University.  We are focusing on two topics: 1) how differences in functional traits influence necromass decomposition rates under altered climatic conditions and 2) characterizing the fungal decomposer communities associated with decaying fungal necromass.  A parallel experiment with the same types of ectomycorrhizal and ericoid mycorrhizal necromass is also being deployed along a well characterized vegetation gradient in Norway to examine how mycorrhizal necromass decomposition varies along natural gradients of soil fertility. More pics and details to be posted soon!