11/28/22: Mycological Madness

The young science of an ancient kingdom

Close your eyes and try to imagine yourself in the ancient city of Athens, sitting next to one of the only Greek writers whose works survived the fall of the Greek empire and the natural decay of artifacts that would take place over the next 2,500 years. The man, named Epicharmus, leans over to you and says dryly, "You are like mushrooms: you will dry me up and choke me to death." Epicharmus was quite charming after all, building a career as a dramatist takes a certain kind of comedic prowess. Society's constant pull towards satire and humor coincides with our interest in the natural world. As Greek philosophers were philosophizing about humanity, meaning, and morals, they pointed towards objects in nature to convey their thoughts. These pontifications provided us with our oldest written evidence describing mushroom species and uses. It seems as though the sapien interest in fungi, just like Epicharmus's diary entries, blog posts, or whatever medium he preferred, has stood the test of time.

Open your eyes and fast-forward around 3 millennium, you're now sitting next to a cheeky blogger who gets a little too much joy out of subjecting her readers to time-travel and the history of all things fungi related. If you can remember back to my earlier posts on fungi, I have covered the following: when and how mushrooms grow, different types of mycorrhiza (arbuscular mycorrhiza: AM, and ectomycorrhiza: EM), edible mushrooms, and the history of mushroom cultivation. Today I'll dig into a topic that is relatively new to the scene when considering the fact that mushrooms have been growing on Earth's terrestrial surfaces for over a billion years and humans have been cultivating them for thousands. We are talking about the field of mycology, folks. From the first dude to categorize fungi apart from plants in the 18th century - to the exciting and novel fungal mapping being done today by researchers such as Giuliana Furci and Toby Kiers, the fungal thread will be followed!

Let us begin with Pier Micheli and Elias Fries. With the publishing of his book Nova Plantarum in 1729, Micheli became the first botanist to group grasses, mosses, and fungi using systematics. Because of his prescient classification skills, Micheli was donned the father of mycology. The next breakthrough in the field wouldn't come until a century later when Elias Fries released Systema Mycologicum to a highly anticipatory audience of fungi fanatics in 1821. I may be playing-up the enthusiasm for mushroom content at the time, as the general public wasn't too interested in mycology until later practical applications were discovered such as Eduard Buchner's extraction of zymase in 1897 or Alexander Flemming's invention of the first antibiotic, Penicillin, in 1928. Nevertheless, Fries was referred to as the Linnaeus of mycology (what's up with these guys and all their nick-names?) because of his major contributions naming and identifying many species. He used characteristics such as spore color and gill type to group mushrooms, ID traits that you can find foragers and mycophiles still using in present-day.

On the topic of innovations we still use today - Lewis Shweinitz, the Tulasne brothers, and Anton de Bary, were other influential pioneers in the field of mycology who would go on to make lasting impacts in how we identify, name, and biologically understand fungi. Shweinitz listed 1,300+ species in his 1822 book Synopsis Fungorum Carolinae Superioris, which served as the first thorough guide to fungal species in North America. The Tulasne brothers revolutionized our scientific understanding of fungal polymorphisms and reproduction cycles throughout the mid-1800's. Anton de Bary followed this up with his innovative work with pathogenic fungi and heteroecism. Being a man of many talents, he was given many names. These include the founding father of plant pathology (history really has a thing for dads), and the founder of modern mycology. I can't overstate the importance of Bary's contributions to science, as he truly dedicated his life to his studies and worked to apply his research to contemporary social issues such as the potato blight causing severe crop loss and economic devastation in 1860's Germany. Bary also provided novel insights on fungal sexuality, lichens, and experimental methods that continue to be implemented by botanists and bacteriologists currently.

The latter half of the 19th century saw significant contributions from Pier Saccardo and Albert Frank. I know what you're all thinking: "Are white guys the only demographic of scientist interested in fungi?" We should all take a moment to consider the lack of diversity in the field of mycology up to this point, not only between sexes, but also between ethnic and social classes. The inclusivity increases a little once we get into the 20th century, but I'll also address how we can all work towards recognizing the accomplishments of scientists from marginalized groups. Back to Saccardo, who in 1872 published Mycologiae Venetae Specimen, a comprehensive guide that described over 1200 species of fungi. His descriptions of fungi in the group Deuteromycota and in the class Pyrenomycetes were additional contributions to the fungal classification system. Shortly thereafter in 1885, Albert Frank coined the term mycorrhiza. Thanks to Frank and his mycorrhizal obsessed contemporaries, the fungal kingdom's ecological importance began to garner serious attention, and the wide-spread association of EM fungi and their tree hosts became the focal point for many forest and plant researchers. Frank's original hypotheses involving water and nutrient exchange between fungi and plants would be expanded upon in the 1900's, and continue to hold true today.

At the turn of the century, Elsie Wakefield and Johanna Westerdijk not only made major contributions to the field of mycology, but served as excellent role-models for how to contribute to the scientific community beyond the influence of research. Through my online sleuthing, I found no mention of anyone being dubbed the mother of mycology (as we know, there are so many fathers!). So, by the power vested in me, based on no qualifications or reasoning that would hold up in a court of law, I hereby declare both women official mothers of mycology! Now that the ceremonial proceedings are finished, we can return to 1910 when Wakefield began her position at Kew, the Royal Botanic Gardens in London. Wakefield would go on to publish over 100 papers on fungal reproduction and phytopathology, in addition to her beautiful illustrations of fungi that can be found preserved at Kew and in her two field guides on British fungi. She would go on to serve as the Head of Mycology at Kew for 40 years and was elected as President of the British Mycological Society in 1929. In 1917, Johanna Westerdijk became the first female professor in the Netherlands. Just like Anton de Bary before her, Westerdijk's work focused on the immediate social, economic, and environmental, issues of her time. Her most notable contributions include her research on potato diseases, dutch elm disease, and the fungal taxonomy system she developed. Westerdijk also emphasized the importance of mentorship and inclusion in science by running a lab full of ladies. She mentored 56 PhD candidates, almost half of which were women. Check out this website to learn more about Johanna, and look into Annie Smith and Lilian Hawker if you're searching for more tea on the British Mycological Society and influential women in science during the 1900's.

While Wakefield and Westerdijk focused on fungi induced plant diseases, the mycorrhizal boom ignited by Albert Frank in the previous century was stoked by Erik Bjorkman, John Harley, and Barbara Mosse. In 1942, Bjorkman developed the carbohydrate theory of mycorrhiza symbiosis. Bjorkman's experiments showed higher frequency in mycorrhizal association with conifers when carbohydrate concentrations were increased in fine roots. In 1959, Harley revolutionized our understanding of mycorrhiza physiology when publishing his book The Biology of Mycorrhiza. Phosphate and nutrient exchange in these symbiotic systems were then pushed to the fore-front. Harley's students would go on to classify the dominant mycorrhizal types associated with different plant communities. This is an ongoing focus of research groups that I will return to at the end of our walk down mycelial lane. Meanwhile, Barbara Mosse wouldn't allow herbs and flowering plants to be left in the dust dirt. In 1962, she established a protocol for cultivation of mycorrhiza in laboratory settings that is still followed by fungi farmers and mycological researchers presently. In collaboration with Roger Koide, Mosse would later publish “A history of research on arbuscular mycorrhizas'' that thoroughly synthesized that impacts of AM fungi on the plant kingdom.

The omics revolution during the 1990's allowed researchers to identify fungal symbionts via RNA analysis, and duos such as Maria Harrison and Marianne van Buuren to describe the molecular basis of fungal nutrient uptake processes. Using RNA ribosomal genes to ID fungi is a much more efficient approach because of the microscopic nature of most mycorrhiza species and the difficulty in distinguishing between their morphological characteristics. In 1995, Harrison and van Buuren discovered fungi phosphate uptake pathways by comparing the DNA and subsequently coded proteins of different fungi species. They were able to confirm the function of a protein found in Glomus versiforme (an AM fungi) by observing the impacts of the complementary gene in yeast cells, which codes for a trans-membrane phosphate transporter. I was unable to access their paper, but I provided an image depicting mycorrhizal phosphate pathways from a more recent publication.

Omics-based research chugged along during the early 2000's, aiding scientists in the discovery of root signaling molecules that facilitate mycorrhizal colonization, whole-genome sequencing of fungi species, and relocating fungi species on phylogenetic trees to more accurately represent their evolutionary relationships. In 2005, Akiyama and colleagues isolated compounds from root exudates, previously known as branching factors, that induced morphological changes in symbiotic fungi proceeding root colonization. I will return to these signaling molecules, which Akiyama identified as strigolactones, in the next blog update. In 2008, Martin et al. published findings from a genome sequencing project that revealed a number of surprising proteins synthesized by the EM fungi Laccaria bicolor. The fungus was found to release various small secreted proteins (SSPs) with unknown functions and enzymes that were able to degrade non-plant cell wall polysaccharides. The authors predicted that the SSPs help to facilitate mycorrhiza colonization of plant roots, and the enzymes allow for the fungus to live freely in the soil, feeding off of soil microbes when carbohydrates from a host plant aren't on the menu. Genome sequencing such as this has further informed the renaming and reclassifying of fungi within more accurate groups based on genetic relatedness.

In search of interesting mycological research happening at this very moment, I found two articles covering both exciting science and scientists. First up we have self-taught mycologist William Padilla-Brown and his work on Cordyceps cultivation. Until Padilla-Brown's independent research efforts, Cordyceps species, used for the medicinal benefits, were only grown in large-scale operations in China and other regions of Asia. Through a process of finding specimens in the wild, collecting their spores, and breeding them in sterile conditions, William learned how to cultivate the fungus on substrate other than their preferred insect hosts. He then published a guide on Cordyceps cultivation and continues to lead education courses on the subject. The next article follows mycologists Giuliana Furci (founder of the Chilean nonprofit Fungi Foundation) and Toby Kiers (VU Amsterdam) as they work with the Society for the Protection of Underground Networks (SPUN) to map the global distribution of mycorrhizal fungi. SPUN's big aspirations will surely be a difficult feat, but it is vital work, as many countries have yet to include fungal species on endangered species lists, or even consider them as organisms that should be protected. Both William Padilla-Brown and Giuliana Furci also serve as great examples of non-traditional routes to careers in research, both being self-taught and successful without the conventional academic training.