What's queer about fungi?

Image: Schizophyllum commune

What could fungi have to do with the LGBTQ community and queerness? Many queer people like to look to nature for examples of queerness, and when we do this, fungi tend to stand out. When we talk about nature being ‘queer’, it is not necessarily that there is anything in fungi that would ever be directly related to an LGBTQ identity. However, they can remind us that some of our widely accepted, but overly simplistic ways to understand sex, gender, reproduction, and identity are not universal in the natural world. Fungi not only live outside our concepts, but do so in a multitude of different ways! 

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Many fungi need a partner to mate with in order to complete their life-cyles. One of the best studied examples of this is found in a very common species, the split-gill bracket fungus, also called Schizophyllum commune, which has a curious way of determining its mating-type.  Mating-types are a concept that some people consider somewhat analogous to sex in animals. This fungus has something called a tetrapolar mating system. In it, two different genetic regions (called mating-type loci) define what an individual’s mating-type will be. For a compatible pairing, two individuals with different mating-types must fuse. Individuals with the same mating types are incompatible. In this non-binary system, each of these loci can have many possible versions (called alleles), and they can mix and match independently. Because of this, unlike the human XY system that can produce only a few different combinations, there are at least 23,328 possible different unique mating-types in Schizophyllum commune! 

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In natural population of the yeast Saccharomyces cerevisiae, mating-type switching can occur allowing cells to alternate between an "a" or "alpha" mating-type. This change happens through a clever genetic trick (called gene-conversion) where the cell cuts its own DNA out at a specific active spot on a chromosome and replaces it with a different segment of DNA from a hidden “silent storage” area on another part of the chromosome. By changing mating-types, yeast cells can mate with different partners, which helps them adapt to their environment and keep a diverse population. This process is essential for their survival and reproduction. In baker’s yeast strains, this mechanism is often defective producing cells with stable mating-types that are fixed as ‘a’ or “αlpha”.

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Probably up to one fifth of all fungal species don’t need to mate at all to reproduce. Many important species do this including moulds in the genus Penicillium - the genus responsible both for the production of antibiotics and blue cheese! 

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The Glomeromycota are another important group of fungi that reproduce asexually. Very few of us ever think about them, because they only exist underground in the soil. They are one of a special type of fungi that produce mycorrhizae (loosely translating to fungal-roots) in association with plants. These fungi help the plants to access water and nutrients. Glomeromycota reproduce entirely asexually - but this doesn't stop them from producing one of the largest spores in the fungal kingdom, with each one visible to the naked eye! 

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There are also many fungi that can reproduce in separate life -stages that are either sexual or asexual.  The stage that isn't able to sexually reproduce is called the  “anamorph”. Often same fungi can later mate, and reach the sexually reproductive stage, and then reproduce in a completely different way - now called a “teleomorph”. This is a way of existing and reproducing that is not really analogous to anything in the human world, but certainly shows that even a fungal identity can be quite fluid. 

This article has only just scratched the surface of the weird and wonderful world of fungi and how they live, exist, reproduce and grow. Fungi complete their life-cycles in a multitude of different ‘non-conformist’ ways, and most of them are very different from our own. It reminds us that many of the simple boxes we use to try to define life on earth are simply not flexible enough to contain the tremendous diversity that exists within nature.

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Images: Clockwise from top left... Fruitbodies of Schizophyllum commune, two yeast cells with mating projections, stained Glomerulomycota cells with terminal spores, colonies of Penicillium on a Petri dish and a “rainbow” display of fungal diversity. 

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Sources and Further Reading 

den Bakker, Henk C., et al. "Clonality and recombination in the life history of an asexual arbuscular mycorrhizal fungus." Molecular Biology and Evolution 27.11 (2010): 2474-2486.

Kirschner, Roland. "Sex does not sell: the argument for using the terms “anamorph” and “teleomorph” for fungi." Mycological Progress 18.1 (2019): 305-312.

Kothe, Erika. "Mating types and pheromone recognition in the homobasidiomycete Schizophyllum commune." Fungal Genetics and Biology 27.2-3 (1999): 146-152.

Ropars, Jeanne, et al. "Sex in cheese: evidence for sexuality in the fungus Penicillium roqueforti." PLoS One 7.11 (2012): e49665.

Sandilands, Catriona. “Queer ecology”. Keywords for Environmental studies. Available at https://keywords.nyupress.org/environmental-studies/essay/queer-ecology/

Images citations:

Schizophyllum commune: Yves Bas, CC BY https://www.inaturalist.org/observations/66785942, via iNaturalist

Yeast image - Saccharomyces cerevisiae mating type a with shmoo responding to alpha-factor visualized via phase contrast microscope. CC-BY-SA-4.0 https://commons.wikimedia.org/wiki/File:Shmoos_s_cerevisiae.jpg, via Wikimedia Commons

Glomeromycota spores taken by Ella Serpell’s lab.

Penicillium image: Crulina 98, CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons

The “rainbow” of diversity shows different mushrooms commonly found in the UK - image Ella Serpell.​