The Forest Fungi Project is a community science initiative aimed at engaging the public and providing an opportunity for participation in the sciences. The project was launched in 2015 by the Lankau Lab of the Plant Pathology Department at the University of Wisconsin-Madison and has since collected over 1,000 samples and engaged more than 950 participants. We hope to learn alongside our participants by using the data to explore factors influencing the distribution and diversity of tree-associated fungi in Eastern Temperate Forests; in other words: which fungi are where – and why are they there? In the face ongoing pressures and environmental changes, understanding the factors influencing our forests, such as fungal partnerships, becomes increasingly important and has the potential to inform how we protect and manage our forested areas.

We invite – and encourage – you to participate. Involvement is easy! Very simply put: we are looking for you to send us tree roots from forested areas located east of and adjacent to the Mississippi River. For a more complete procedural outline, select the PARTICIPATE tab located in the above menu bar.

To learn more about the biology behind the project, please explore the expandable menu below by selecting each topic to show associated information.

We look forward to learning more about this fascinating, complex, and highly important system alongside you, and we thank you for your time and efforts.

+What are fungi?

If you were exploring this question ~50 years ago, you would have learned that fungi were seedless plants, similar to ferns, mosses, and liverworts. That, however, is not the case! In fact, fungi are more closely related to you, as an animal, than they are to plants all together. (No joke!)

Fungi are members of a distinct group of living organisms that are neither plant, animal, bacterium, or anything else but just that: fungi. This group was previously defined by morphological (or body shape) and physiological (body function) evidence, which has since been further supported by DNA evidence.

Fungi are highly diverse in form and function, and range from large mushroom fruiting bodies, to the mold on your strawberries, to soil-dwelling species that are essentially only perceptible through DNA sequencing – and far, far beyond. They do not make their own food, as plants do through photosynthesis, and instead rely on the consumption of other organisms. This is often why you see fungi growing on dead logs or branches. Fungi also tend to have similar compounds found in their cells (notably, a tough polymer called chitin) and reproduce with small structures called spores.

+Which fungi associate with trees?

Although fungi can associated with trees in a number of different ways, including as pathogens and endophytes (organisms that live within plants without causing disease), one of the most well-known tree-fungal interactions is between tree roots and specialized fungi called mycorrhizal fungi, which translates to “fungus root” fungi.

Mycorrhizal fungi are fungi with a unique ability to associate with plant roots: a relationship that primarily relies on the trading of services between plant and fungi. Plants are notoriously good at making carbon-based sugars (AKA: food!) through photosynthesis, but are often times limited by other factors, such as water or mineral nutrients like nitrogen or phosphorous. Fungi, on the other hand, are unable to make their own food, but are relatively well adapted to accessing mineral nutrients and water from the surrounding soil. By trading services, they can efficiently outsource their limitations to others that are better at such tasks. This partnership is so successful that more than 90% of all land plant families are thought to associated with mycorrhizal fungi! And most have been doing so for a very, very long time.



+Ectomycorrhizal Fungi vs. Arbuscular Mycorrhizal Fungi

There are multiple types of mycorrhizal fungi, each group being defined by how they uniquely interact with plant roots. The two most abundant and widespread type of mycorrhizal fungi are ectomycorrhizal (EM) fungi and arbuscular mycorrhizal (AM) fungi.

The prefix “ecto-” means outside, and usefully describes one of the major differences between EM and AM fungi. Ectomycorrhizal fungi forms a thick fungal coating, called a mantle, on the outside of the plant root tip; additionally, though it enters the plant root, it persists in the open space between the plant cells and doesn’t press into the membrane of individual cells.

Arbuscular mycorrhizal fungi, on the other hand, don’t form a thick fungal mantle on the outside of the root. Additionally, they do press into the individual plant cells – much like pressing your fingers into the outside of a water balloon without rupturing it – which maximizes their surface area for service exchange. Arbuscular mycorrhizal fungi more technically belong to a broader category called “endomycorrhizal” fungi, which are named after this action of pressing into the plant root cells.

Although both EM and AM fungi act as mycorrhizal partners, or “symbionts”, and perform the basic exchanges that commonly characterize these relationships, they do so in rather different ways and perhaps with different degrees of efficiency. Additionally, the vast majority of tree species associate with either EM and AM fungi exclusively. There are only a select few that have the ability to associate with both simultaneously.

+Fungal Biogeography

“Biogeography” is a fancy word describing the scientific study of “who is where”. Where does a particular fungal species, or group of species, exist, and why does it exist there? Why is it not also found in this other location? Or, why is it found everywhere?

As a scientific community, we have centuries of research documenting the biogeography of plants and animals. However, likely due to their relatively small size and difficulty in identification (not to mention the historical confusion; see “What are fungi?” above), fungi lack these records. As we continue to understand just how important fungi are in the functioning of our ecosystems, it becomes increasingly more necessary to know which fungi are where. Your contributed samples will help us do just this! 

+Eastern Temperate Forests

There is currently an interesting north-to-south, or “latitudinal”, pattern with regard to mycorrhizal partnerships in the temperate forests of eastern North America. Northern forests tend to be dominated by trees that associate with EM fungi, whereas southern forests tend to be dominated by trees that associate with AM fungi. The more central locations have a roughly even split between the two and depend on site.

Why are our forests structured in this way?

This is a large and very important question that we hope to pursue using – you guessed it – the results from your samples! With your help, we hope to find greater clarity as to what is responsible for this pattern and how it might change as the world continues to do so as well. We encourage you to be a part of this exciting frontier!

+DNA Sequencing

DNA sequencing involves the “reading” of a particular stretch of DNA. There are four different “nucleotides”, or molecules, that comprise DNA; let’s think of these as alphabetical letters (which is useful – since these molecules are commonly denoted as A, T, C, and G). These four letters can be organized in various different ways depending on the particular DNA present, which often varies by species.

However, just like alphabetical letters, the order of these letters matters and carries information. For example, by changing the order of the letters R, T, and A we can get multiple different meanings that carry different information: RAT, TAR, ART. Similarly, an ordering of ATCCCCGTT carries different meaning than CGGTAATTG, and could carry useful information distinguishing one fungal species from another. Therefore, our goal with your contributed samples is to determine which fungi are present by looking for unique orders, or “sequences”, of nucleotides that identify particular species.

This material is based upon work supported by the National Science Foundation under Grant Number (NSF 1651931)

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.