Genetics and Evolution of Gyromitrin (PhD Research)

Lorchels (Gyromitra spp.) are iconic primarily for what they are not – morels (Morchella spp.), choice edible mushrooms that are cultivated and foraged with fervor. Some lorchels contain a mycotoxin called gyromitrin, which is converted into monomethylhydrazine in the stomach, an ingredient in rocket fuel that is as bad for you as it sounds like it would be. You'd think this would be a deterrent to their consumption. However, in Finland, the deadly poisonous Gyromitra esculenta is widely consumed as a delicacy after being prepared using a tedious boiling procedure to rid it of the majority of its gyromitrin. Across the United States, especially in the Midwest, there is also a culture of consuming certain lorchel species. Some of these are anecdotally considered nontoxic, or at least less toxic than Gyromitra esculenta.

There are about 85 species in the lorchel family, but only a handful are common in Michigan. From left to right: Gyromitra ancilis, Gyromitra brunnea, Gyromitra korfii group, and Gyromitra venenata. Only G. venenata is known to contain gyromitrin.

1. Distribution of gyromitrin in the lorchel family Discinaceae

Our limited understanding of which lorchel species contain gyromitrin motivated us to develop a new gyromitrin assay and to test as many lorchels as we could get our hands on, culminating in a manuscript that was published in the journal Mycologia (available as a free downloadable PDF here). The main findings of our research are that gyromitrin has a discontinuous and more limited distribution than expected. We detected gyromitrin in all tested specimens of the Gyromitra esculenta group as well as Gyromitra leucoxantha. This distribution is consistent with a model of horizontal gene transfer. To the delight of lorchel foragers, we did not detect gyromitrin in any tested specimens of G. brunnea, G. caroliniana, or the G. korfii group. ​The many mushrooms that were acquired for this project are also contributing to taxonomical investigations. For example, specimens collected from University of Michigan's Stinchfield Woods were described as a new species in the Gyromitra korfii group, Gyromitra americanigigas (free PDF here). Your donations were invaluable in our gyromitrin and taxonomic work and facilitate ongoing genomics research. 

2. Discinaceae phylogenomics and evolution of gyromitrin

Something I learned from the first project is how uncertain we are of the true evolutionary history of Discinaceae, which in turn limits our ability to infer the evoution of gyromitrin. We are sequencing the genomes of dozens of Discinaceae species – whether truffle, cup, or stipitate mushroom – and using this large dataset to create the most accurate evolutionary history of Discinaceae ever. Our phylogenomic tree allows us to make taxonomic revisions to the family to reflect how species are actually related to each other. These genomes also provide rich insight into the ecology and evolution of the lorchel family. By utilizing ancestral state reconstruction on our revised species tree, we can model how gyromitrin has evolved in the family over millions of years.  

3. Identifying the genes responsible for gyromitrin biosynthesis

​​Fungi produce an enormous diversity of powerful secondary metabolites (think penicillin, lovastatin, and cyclosporin, among many others), but the genetics and evolution of the vast majority are unknown. ​Gyromitrin belongs to a rare class of compounds containing a nitrogen-nitrogen bond. Only about 0.1% of characterized secondary metabolites belong to this group. We have no idea what genes are responsible for gyromitrin production, so our final goal is to discover its genetic underpinnings. By utilizing our genomic dataset and employing bioinformatics strategies, we will identify putative gyromitrin biosynthesis genes. This research could expand our understanding of nitrogen-nitrogen secondary metabolite biosynthesis specifically and fungal chemodiversity in general, aiding in the discovery of novel chemicals.

Taxonomy of Crust Fungi

Crust fungi (or corticioid fungi) typically do not evoke much excitement or command great respect. However, they are extremely diverse and ecologically important. This is in part due to the fact that crust fungi are a form group. They are defined not by shared ancestry but by having the same crusty two-dimensional form. In other words, wherever you look across the basidiomycetes, you find crusts. Crust fungi make up for their lack of macroscopic charisma with extraordinary microscopic diveristy, representing the entire spectrum of spores, hyphae, and sterile cells of the Agaricomycotina subphylum. While many crusts break down dead wood, some form mutualistic associations with trees. Indeed, in some forests, crust fungi are the dominant members of the ectomycorrhizal community. The bottom of sticks and decaying logs is a great location to find crusts, but you can also find them on leaves, under conifer duff, on bark, and even on the underside of rocks! I endeavor to document North American species at my other website, crustfungi.com. In the future, I'd like to make this website dynamic so that crust enthusiasts around the world can upload profiles for their favorite species. If you are a web developer and want to work on a Wordpress version of this website so others can participate, please let me know!

Other Projects

All the research mentioned below, and more, can be accessed from the Downloads page as free PDFs.  

Zoosporic Fungi Single-cell Sequencing

I was part of a collaboration to document the unculturable microscopic fungi infecting algae and other little guys in aquatic ecosystems. What we found: a huge diversity of unknown fungal lineages (even new phyla!) making up what is referred to as "dark matter fungi". Check it out at mBio. 

Metabarcoding of Arbuscular Mycorrhizal Fungi

For my Master's thesis, I characterized the communities of arbuscular mycorrhizal fungi associating with switchgrass, a perennial biofuel feedstock, using long-read, high-throughput PacBio metabarcoding. Read more at Applied and Environmental Microbiology. 

Taxonomy of the Anamorph Sphaerosporium lignatile

As part of the international Fungal Systematics and Evolution (FUSE) collaboration, we resolved the familial status of the previously unplaced fungus Sphaerosporium lignatile as Pyronemataceae (Pezizales), closely related to the eyelash cup fungus (Scutellinia​). Check it out here. 

Phaeotremella dejopia, or TeeHųųcnįk

Collected in 2018 from Wisconsin, I described a large, foliar jelly fungus as a new species, Phaeotremella dejopia. The specific epithet refers to Dejope, the name of the region from which the holotype was collected in the Ho-Chunk language. Read more about it here.

DNA Barcoding of the 2018 Smith Foray Macrofungi

We DNA barcoded 63 mushrooms that were collected during the 2018 Smith Foray in Mazomanie, WI. Three species were first reports for the United States and 15 were new records for Wisconsin. The manuscript was published in The Great Lakes Botanist. 

Boston Harbor Islands Fungal Biodiveristy Survey

As my first experience in mycology, I worked with the nonprofit organization Boston Harbor Now, Harvard University, and the National Park Service in collecting and documenting fungi from the Boston Harbor Islands National Park. Our findings were published in Northeastern Naturalist.