February 16, 2021

The hidden world of fungi

By Conor McKechnie and Dodi Axelson

The hidden world of fungi

Conor finally brings the 15 minutes of fame to fungi – mushrooms being second only to his ’microbiomania.’ We invite you to the beginning of the journey to understand fungi and mushrooms.

CONOR: Dodi, it's December, and the nights have closed in here in the Northern Hemisphere. And because of the pandemic, our appetite for the outdoors is still here, even during the working day, right? You do walking meetings, isn't that right?

DODI: Every day I am out and about. I call it doing a meeting on my feet.

CONOR: And so where do you walk on these peripatetic meetings?

DODI: Fortunately, there are a lot of forests to choose from in Sweden, and I live close to one or many. So, I am out with the trees.

CONOR: You know what I love about the forest?

DODI: Do tell.

CONOR: Mushrooms.

DODI: The fungus obsession that you have, here we are.

CONOR: We finally got to the episode on fungi and their role in our world.

DODI: So that is what matters in this episode of Discovery Matters.

CONOR: I've just picked up on the verge of path, a waxy little white thing. Really quite small. Does that mean they're attached to the stem when they go down, when they attach?

GUEST: Yeah. Yeah, so it sounds like you might have found a snowy waxcap.

DODI: A snowy what? And who is that?

CONOR: A snowy waxcap. And this is Clare Blencowe.

CLARE: I work for the Sussex Wildlife Trust, where I manage the Sussex Biodiversity Record Centre. So what I do for a living is work with sort of volunteer naturalists and recording groups in order to gather data about our county's wildlife. My hobby is going out looking at mushrooms and fungi.

CONOR: And we were on an extreme socially distanced mushroom hunt for a while. We were actually about 90 miles apart from each other. But talking on the phones. We walked, it was raining like crazy.

DODI: That's awesome.

CONOR: A big sorry for the quality of the audio. I was out there walking in the rain in the woods near my house, on the phone, and...

CLARE: I'm walking through some woods, which are sandwiched between my village and the industrial estate on the edge of the village. And it says local nature reserve. These sorts of places are really important bits of our landscape for providing access to green space, which I think we've all really valued during this period that we're in this year. I just walked past them, glistening inkcaps poking out of a pile of rotting logs.

CONOR: Clare is also the founder of The Mycological Book Club. Yes, that is a book club for everything mushrooms. It's brilliant. And that's actually how I stumbled across her.

CLARE: It was fairly near the beginning of the lockdown. I think probably like a lot of people, I'd found myself trapped in a pattern of constant news scrolling...

<<snippets of news stories>>

CLARE: ...fueling increasing levels of anxiety, and I thought I've got to stop reading the news. But it felt like a bit of a big step to just get off the internet entirely. So I sought refuge in the Biodiversity Heritage Library. The website has overseen the digitalization of just a huge amount of historic literature relating to biodiversity across the whole world. And you can sort of get yourself in there and read books and look at illustrations from previous centuries. I found it a wonderful escape.

And also really fascinating. Because in the 19th century, people had a completely different way of writing about natural history. And I thought, oh, this is so interesting. I'd love to talk to other people about this. And of course, Twitter™ makes it really easy, to just set up a Twitter page and tell people that you've got a hashtag. I think at that point, there were about two other people that joined in. It was just a time when all social engagements were off. So, I thought you know, it'd be really nice to have something to look forward to, something that's a date in the diary at an allotted time to sit down and talk to people about something like how book club works. So, it was really that simple.

CONOR: It's the first Tuesday of every month on Twitter. The hashtag is #MycoBookClub. The Twitter account is the same actually, @MycoBookClub. You'll be surprised just how much there is to read out there and how many people are interested in mushrooms and fungi and discussing books about them. Anyway, back to our extreme, socially distanced, fungal foraying.

CLARE: I just walk past them, glistening ink caps poking out of a pile of rotting logs. There's a whole sort of group of different mushrooms that get referred to as ink cap. And they're called ink caps because they have this feature of dissolving gradually over time. They turn into a sort of inky dripping consistency, which will drip down from the edge of the cap.

So, one that people might be particularly familiar with is the shaggy ink cap, or the lawyer’s wig, and that one's a bullet-shaped big white mushroom. It’s quite tall and from Italy. As it matures, the base of the mushroom will sort of kick out, and then it will gradually start to dissolve from the bottom and towards the top. It's covered in these glistening, tiny, mica-like particles, which gradually wash off with the rain. But if you catch them when they're just emerging, they can look quite sparkling.

CONOR: And this, for me, is just like the joy of it. You can just go out into the fields and the woods and immerse yourself in the landscape. And you're right at the frontier of a huge body of incredible science that we utterly depend on that we just know so very little about.

CLARE: I can entirely believe that this hugely understudied kingdom of organisms does all sorts of interesting, useful stuff, which benefit people. I think, kind of understanding the extent to which that can be applied to human existence is probably still in its fairly early stages. But I think it's a symptom of the fact that they've been so understudied for so long that it is this vast and exciting field that has so much promise. I can see why people get super excited about what fungi can do.

DODI: Oh, yes, I can vouch for that. Having had to hear you rant about the amazing kingdom of the fungi.

CONOR: Yes, I kind of get a little over enthusiastic. But look, with good reason.

CLARE: I think one of the things that I'm always keen to get across when I'm talking to new people is the art of observing fungi. Especially nowadays, it's a very attractive idea that you can just point your phone at something and get a photo of it and find out what it is. Post a picture of it on the internet and ask somebody to tell you what it is. But many species are quite cryptic or quite nuanced in their character.

Okay, one of the joys of studying fungi for me is you really need to kind of put your whole self in it. You do need to get down and look at it and look at the whole thing and learn the sort of terminology to help you understand the details of its kind of visual features. But you also need to sniff it, feel it. You need to interact with it. In order to get an understanding of new features, I think you need to gain more familiarity, more sort of comfort with touching fungi, observing fungi, and keeping yourself safe by washing your hands before you have your sandwich at lunchtime. I think just appreciating their incredible diversity and fascinating and weird features that they have.

DODI: So, I get they are understudied. But why are they suddenly so important?

CONOR: Well, it turns out, we should all be totally gobsmacked. Because if it weren’t for fungi, there would be no plants, no animals, no terrestrial life on Earth. At all.

GUEST: About 500 million years ago, before plants had moved onto land or the ancestors of plants had moved onto land, there were these algal ancestors. The plants were living in fresh waters and lakes and rivers when washing up onto these muddy shores. But unable to make a life in the open air that was scorched and desolate, hot and seered with radiation. It was in these early moments that we think these algae struck up a relationship with some fungi who were able to scavenge in this solid ground, knowing this medium of the land in this terrestrial place. The algae were able to eat these energy-containing carbon compounds which you could then exchange with these fungi for mineral nutrients that they've managed to scavenge from the ground, from the environment that they were living in.

DODI: Who is this guy?

MERLIN: I'm Merlin Sheldrake. I'm an author and I'm a biologist.

DODI: Merlin, like the magician?

CONOR: Yes. And the magic he's entangled with is the magic of mushrooms.

DODI: Sounds like a...

CONOR: No, we're not doing that joke.

DODI: No fun. No fun.

CONOR: So, Merlin's book is all about fungi and humanity's extraordinary interrelationships with them.

MERLIN: Modern plants arise from this relationship. And still to this day, 90% of plants depend on these fungi for not just nutrition but also for water and for their health. What we think of as plants are really algae that evolved to form fungi, and fungi could evolve from algae.


MERLIN: These fungal relationships are totally fundamental to plants. And of course, plants are totally fundamental to life on this planet and make up 80% of the biomass on the planet. And at the base of the food chain they sustain all recognizable life on Earth, including our own.

DODI: Okay, okay, let me get this straight. 500 million years ago, fungi made a pact with algae, to trade nutrients for carbon, and that gave rise to plants. No fungi, no plants on land. No life on land. No humans.

CONOR: Yep. So, fungi...this kingdom of life is kind of a big deal.

DODI: They're like everything.

CONOR: Exactly. It's everything. They've only been a kingdom since like, 1969 when they were pulled out of plants. So, I wanted to ask Merlin, this amazing kingdom of organisms, they're not plants. They're more in common with animals. Why has it been so hard for people to study this kingdom compared with plants, animals, and the other kingdoms, As Clare told us earlier?

MERLIN: In physics, you have dark matter and dark energy, this energy and mass that we know nothing about, and yet makes up a huge proportion of the universe and the microbial world — fungal, bacterial, and archael world. I think it is dark life. You know, people show graphs. And there's large sections of the graph labeled unknown. These parts are these life forms that we know exist. We know they're in the world. We know they’re doing things we know are ancient, or have these long histories. We just can't grow them in a controlled environment. So we have no way to tease them apart using our conventional experimental methods. What exactly is doing? What and who's doing what, where?

CONOR: So it's just like a mess, right? We can't see what's right under our feet. This is the other thing I love. It's just right there. Even the great heroes of biological science failed when it came to fungi.

MERLIN: People haven't known fungi that have this very patchy taxonomic history, and even Linnaeus writes about them, saying that this fungi era is chaos, the Chaos Fungorum, a scandal of art. No one knows what's a variety, and what's a species. People were still debating whether there were houses that insects built up until the 18th century.

And this comes first from the classical writers who had a very unsystematic way of thinking about these organisms, partly because there was so little material to study, unlike plants where you have all these shoots and leaves and roots, see how fast he describes truffles. But he only says what they aren't — he says they have no shoots, no leaves, no roots, no veins, and he can only say what they don't have.

DODI: Oh, well of course he's referencing the great Swedish biologist Carl von Linné.

CONOR: I know there's just altogether too much Sweden already in this episode. We'll go even further.

DODI: But Conor, this is changing, right? Now we are seeing this surge, delayed though it is, in the study of fungi and their practical uses. So, why is it now that we have finally caught up to this?

CONOR: Well, in part Merlin says it's because of the development of better scientific tools and ways of studying them.

MERLIN: Just as these techniques have opened up new possibilities in other aspects of the life sciences, so they have in mycology. Because you just simply have more resolution. For example, you can use certain dyes or stains or fluorescent molecules to visualize the flow of materials from fungal networks and use labeling techniques that allow you to track the flow of labeled isotopes of various molecules. Not just through a network, but track them into different DNA of different organisms so you can work out where in the community these compounds are passing.

So the resolution has just increased a huge amount. For example, in the study of mycorrhizal fungi, which formed symbiotic relationships with plants. We've learned a lot about their trading habits, the way that plants and fungi trade nutrients with each other. And this has been possible by having these very finely controlled microcosm systems which use labeled isotopes of phosphorus and carbon and measure the fluxes between these organisms. All this wouldn't have been possible even 30 years ago.

DODI: Awesome. Okay, so life sciences tools and technologies are finally embracing the fungi.

CONOR: That's exactly right. And it's about time. And we've been benefiting from fungi for thousands of years, in so many ways. And now especially in health science.

MERLIN: So there's medicines, of course, penicillin being the most famous example produced by a mold or fungus. Other drugs are less well known but are still huge, like cyclosporin, which makes organ transplants possible. The immunosuppressant myriocin, which is an MS drug, a multiple sclerosis drug. So drugs are a biggie, all sorts of things. Engineered strains of yeast produce many of the vaccines that we have in circulation, and in food and drink. Of course, alcohol ties in with food. Now we've recruited fungi to break things down for us for a long time, for example, miso and making soya sauce is a similar process. Alcohol, making it even the kind of domesticated decomposition process of turning sugar into alcohol, at the least turning sugar into alcohol.

But there are lots of other things. Citric acid, for example, used in all fizzy drinks is produced by Aspergillus fungus. So that's a huge fungal job that's being done. And hiding in plain sight there's lots of enzymes in industry, from those used to make stonewashed jeans, to those in cheese making and clarified juices. So there's loads of things that they do, and they've done for a long time, and that we don't think much about.

DODI: Well, Conor, you are certainly making a good case for the debt of gratitude we owe to fungi. Everything good that comes on a weekend, like cheese, wine, bread, and beer.

CONOR: Totally.

DODI: This is thanks to these little guys who are working hard for us all the time.

CONOR: And on the weekday, when we're looking at medicine and the future of medicines, I mean, there's fungi all around us there as well.

DODI: So, let's look ahead. Then where is this new understanding of fungi going to take us?

CONOR: In so many different directions. It was very hard as I sort of pulled this episode together to stay focused on just one area. So, there's real practical uses of fungi, where we can put them to work for us. And then there's kind of the more fundamental research going on into understanding not just what these organisms are, but how they are, what is that actual mode of being. And I want to talk about that first. And we can maybe, in another episode, come back to the practical uses. Because the mode of being a fungi challenges the very concept of what it means to be an individual. Remember when we talked about the microbiome, and we learned that we are full of all sorts of other bacteria and fungi and organisms, and we're not maybe just a human?

DODI: Just because it's our body doesn't mean it belongs entirely to us.

CONOR: Exactly. And then Merlin comes up with this concept that actually challenges the idea of where intelligence comes from.

MERLIN: There’s this question of how decentralized organisms can stay in touch with themselves. One of the things I discuss in my book is the very beginnings of a completely new line of inquiry within the fungal world, which is that of this electrical communication, the work of a biologist called Stefan Olson who was in Sweden in the 1990s.

CONOR: So, somehow always coming back to Sweden for the mind-blowing facts, right? But look, this is really cool. And it explains a lot. So Olsson worked next door to a team of neurobiologists who were using microelectrodes to study moth's brains.

MERLIN: They said, ”Can I borrow your microelectrodes you've got stuck in the moth’s brains? (They're studying math brains, they’re studying the passage of the way these waves of electrical activity pass in most neurons.)

CONOR: Now I want you to listen to something. Just listen to the audio.

<<rhythmic sound>>

CONOR: Can you hear that?

DODI: I can.

<<rhythmic sound>>

DODI: It's a sonic representation of the activity of the fungus as it eats Merlin’s book. But it's a representation. So these are instruments recreating the sounds.

CONOR: No, they're not instruments. It is the bioelectric field being represented in an oscillator. And that's just the noise the oscillator makes as it records the bioelectric field of the fungus.

DODI: That is completely freaky.

CONOR: Totally, totally bonkers. And we'll come back to that, another little myco song a little bit later on. But it is so meta, right? That is Merlin's book being eaten by a Pleurotus, an oyster mushroom fungus. It's amazing.

DODI: So, it's talking to itself. It's like sitting at dinner with somebody who eats their food and makes all the pleasure noises of something that tastes good.

CONOR: It's brilliant. And actually, if you go onto Twitter, and if you find Merlin's Twitter account, you can watch him eat the fungus that ate his book. I mean, it's like, seven levels of meta. But look, you know, talking to itself, it depends on what you mean by talking. And it depends on what you mean by itself. And it gets even crazier, because it seems that fungi really do sense their surroundings and react to them.

MERLIN: They found that the fungus they just produce action potentials, or actual potential-like spikes, and it seems to respond with these spikes to its environment. So, you put a block of wood on this wood-rotting fungus, and this is food.

And this is a major event. The fungus increases the relative firing of these electrical impulses, and you take away the wood and the rate of firing decreases.

CONOR: So, the fungus is responding to its environment. And in some sense, communicating what it's finding and where it is to all the other parts of itself. And really quite rapidly, not slowly in the way that we might associate plants would do. But much more the way an animal would do.

MERLIN: Yeah, just in the same way that you touch the floor with your toe, and electrical impulses pass up your nervous system. And they communicate to the rest of your body that your toe is in this vicinity experiencing this kind of sensation. You know, it's a very effective way for organisms to stay in touch with themselves, which is why we depend on it so greatly. And it's just fascinating that within the lives of these very different organisms, this kind of signaling may take the place of these qualities of brains and neurons. These have their roots in much more ancient cellular traits that have existed for a very long time.

DODI: Is Merlin actually saying that fungi think? And if so, when are they going to take us over?

CONOR: Okay, so, you know, I'm never afraid to ask the really big questions on this podcast. So that's exactly what I said. I said, ”Okay, Merlin, so are they conscious? Could we talk to them? What would they say?” I mean, who wouldn't want to have a fun-gi to talk. See how careful I was?

DODI: That's pretty stinky.

MERLIN: I don't think that consciousness is a trait restricted to humans. To what degree is it not restricted to humans? I'm not sure. But if it was discovered, at some point in the future, that fungi had some kind of consciousness, I'd be very excited by that. And I would want to keep my mind open to the possibility that it might happen, because I think it's a more interesting world.

CONOR: Isn't that just fabulous?

DODI: It is fabulous.

CONOR: You know, for thousands of years people have known about mushrooms, but only very recently are we beginning to understand some of the real importance of where they come from, the fungi that give rise to mushrooms.

DODI: I think it's perfect that this is going to be a topic that we revisit.

CONOR: We will definitely come back here because there's sustainability, there's medicines at play. There's eco-remediation. There's a lot going on, but we really must finish with the audio from this tweet.

<<piano music>>

CONOR: So, that is Merlin accompanying his fungus eating his own book on the piano. Brilliantly talented researcher. Couldn't we all be like that?

DODI: I wish.

<<piano music>>

DODI: And on that note, thank you for listening to this episode of Discovery Matters.

CONOR: And subscribe wherever you get your podcasts and rate us. That will be grand. Thanks very much.

DODI: Bye for now. Our executive producer is Andrea Kilin. Discovery Matters is produced in collaboration with Soundtelling. Production and music by Thomas Henley.

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