Mycology 101
Wikipedia (2009)
A collage of various fungi to show the diversity. Top row from left to right; Amanita muscaria and Sarcoscypha coccinea, bottom row left to right; Aspergillus ssp., a Chytrid, and bread mold.
Fungi are a distinct group of organisms that differ from plants and animals. Hyphae, thin thread-like cell structures, make up the main life stage of fungi. These hyphae have a remarkable ability to penetrate and extend into their surroundings. When hyphae have grown into a thick dense mass, we call this mycelium. Hyphae and mycelium excrete enzymes that break down substrates, which the fungus then absorbs to obtain nutrients.
What makes fungi so unique, is the diverse forms it can take. Most people are familiar with the stereotypical "mushroom" fruiting body, which is the sexual reproductive structure composed of mycelium. However, fungi can take other forms such as molds and yeasts.
Vandegrift, R. (2016)
A cutesy-realistic drawing of the difference between Basidiomycetes and Ascomycetes. On the left, an Amanita muscaria mushroom is drawn showing basidia and what basidiomycete hyphae look like under a microscope. On the right, a morel is drawn showing asci and what ascomycete hyphae looks like under a microscope.
Two phyla of fungi that create fruiting bodies, is Basidiomycota and Ascomycota.
Basidiomycota are what people think of when they see "mushrooms" and think of fungi. Spores are created in the Basidia, where the phyla gets its name. Some common basidiomycete fungi are the Fly Agaric (Amanita muscaria), Giant Puffballs (Calvatia gigantea), and the button mushroom (Agaricus bisporus).
Ascomycetes can also form fruiting bodies, but also have much more range of forms they take. Ascomycetes create their spores in sac-like structures called asci. Some examples of ascomycete fungi are bakers yeast (Saccharomyces cerevisiae), morels (Morchella ssp.), and true truffles (Tuber ssp.).
Morchella
Black morels (Morchella importuna) fruiting at the MSU Horticulture Farm research site
One of the more iconic and recognizable mushrooms, morels are famed for their distinctive appearance and their exquisite taste. This fungus is characterized by its unique 'pitted and ridged' cap, as well as its earthy and nutty flavor. Morels have been recorded on all continents except Antarctica, thus with its widespread nature it comes to no surprise it is as coveted as it is in many countries around the world.
Extending beyond the culinary desirability, morels have found their way to the heart of mycology. Scientists like us are still discerning much about their lifecycle, ecological roles, and fruiting conditions.
Machacekcz. (n.d.)
“Morel cross-sections showing the stipe is hollow through the stem to the base of the cap"
Morels are easily distinguished fungi from others. The pitted and ridged caps often catches peoples eyes first and the easiest way to determine if something is a morel. This cap serves as the surface that spores are produced and released, or hymenium. Another diagnostic property of morels, are that the caps are attached to the bottom of the stem, or stipe. One last determination to confirm if something is a morel, is to cut the fungus in half and confirm that the inside is hallow.
Conidia, the white powdery substance seen in the picture to the left and blow, is an asexual reproduction structure. Conidia are asexual spores formed by conidiophores and are thought to be helpful for both survival in undesirable conditions, and also helpful for dispersal to new locations through methods like water or wind. Cultivators of morels like seeing conidia as we can confirm the presence and growth of morels!
Morchella clades
Morchella importuna from our MSU demonstration cultivation site
This clade typically has morels with caps that tend to be more elongated, and are darker or black in color. These morels are often found and associated with burned or disturbed areas. These morels are of interest to scientists and growers alike as the Elata clade has many species that have been successfully cultivated.
Morchella americana
This clade is typically more honeycomb looking than the others morel clades, and is typically khaki or yellow in color. These morels are commonly found within deciduous forests and trees, or areas with organic rich soils. These morels have yet to have their secrets determined to be able to cultivate them.
Morchella rufobrunnea grown indoors in the MSU plant sciences research greenhouses.
The most basal clade in the Morchella genus, their caps are typically a grey-brown to a red-brown in color. When handled or "bruised", spots on the morel can turn a reddish color, giving them the nickname the "blushing" morel. Some of these species have been successfully cultivated. These morels first described in Mexico, have been known to be found growing in fall as well as spring.
Du, X.-H., & Yang, Z. L. (2021).
The above phylogeny from Du and Yang 2021 shows a recent phylogeny of the genus Morchella. Some features are highlighted or marked, such as cultivatable species highlighted in light yellow, fire-adapted species, species known to produce ascocarps in the autumn, as well as the mating
Du, X.-H., & Yang, Z. L. (2021).
Above is the lifecyle for morels as we know it as depicted by Du and Yang 2021.
The morel lifecycle is one that recently has been in focus for research. Efforts to understand the Morchella lifecycle are partially in efforts to help cultivation efforts, but also to better understand other ascomycete fungi lifecycles and mating habits.
In Morels, there are two mating types we are aware of, MAT1-1, and MAT1-2. In most Morchella species, to produce an ascocarp both mating types are required. Morchella rufobrunnea is an exception, and is thought to be homothallic and thus have both MAT1-1 and MAT1-2 and can mate with itself (Butler 2007).
Notice in the lifecycle, there is a section of dashed arrows. This section is still unconfirmed, and is being studied. This undetermined area of the morel lifecycle is interesting because conidia can be very prevalent when cultivating morels. Clarifying this last piece of the morel lifecycle could help improve our cultivation efforts (Du and Yang 2022).
Citations
A series of fungi. (2009). Wikipedia. Retrieved from https://en.wikipedia.org/wiki/Fungus#/media/File:Fungi_collage.jpg
Vandegrift, R. (2016). Cute watercolor cartoon showing the difference between ascomycete Morchella, and Basidiomycete Amanita. Xylaria.net. Retrieved from https://xylaria.net/2016/09/30/basidiomycetes-and-ascomycetes/.
Liu, Q., Ma, H., Zhang, Y., & Dong, C. (2017). Artificial cultivation of true morels: Current State, issues and perspectives. Critical Reviews in Biotechnology, 38(2), 259–271. https://doi.org/10.1080/07388551.2017.1333082
Machacekcz. (n.d.). Slices of morel mushrooms on wooden cutting board stock photo. Istock by Getty Images. photograph. Retrieved from https://www.istockphoto.com/photo/slices-of-morel-mushrooms-on-wooden-cutting-board-gm1142169632-306293874.
Du, X.-H., & Yang, Z. L. (2021). Mating Systems in true morels (Morchella). Microbiology and Molecular Biology Reviews, 85(3). https://doi.org/10.1128/mmbr.00220-20