Mycorrhizal networks function like a market economy. There is a system of exchanging things of value in underground mycelial networks.. We are very honored to welcome with the brilliant and eloquent Toby Kiers, who has pioneered so much to our collective understanding of how mycorrhizal market economies work.
- What is a market economy and how does it work in underground networks?
- Mechanical descriptions of how these trade deals are made and what science can tell us so far about how exchanges are initiated and
- How mycorrhizal networks work with multiple communities of plant species
- How to track and quantify the chemical exchanges between species in the lab
- Carbon sequestration of soil and mycorrhizal fungi
- SPUN "The Society for the Protection of Underground Networks"
Toby Kier's Website: https://tobykiers.com/
TED Talk "Lessons from fungi on markets and economies": https://tobykiers.com/publication/
Press release SPUN Launch
You're listening to the mushroom revival podcast. Something like an economy exists within the mycorrhizal networks that sustain life on earth there is a system of generating and trading stuff of value. And today on the show, we are very honored to be speaking with the brilliant and eloquent Toby cares who has contributed so much to our collective understanding of how mycorrhizal market economies work.
Honestly, this is one of my favorite episodes. And Toby was so brilliant and how she described the scenarios of how multiple organisms interact. And putting it into a way in which normal average Joe's can can try to comprehend, which I think is really important as we venture further and further into the mycological world is taking that juicy information and bringing it to the masses. But before we get into it, the review of the week. So this one is by Yves the cryptid. And the title is great podcasts. And the review is I am relatively new to mycology and I find this podcast very entertaining and informative. One thing I would be interested to hear more about is the field of medical mycology overall, really good. We actually covered that in an episode with Dr. Neil gow, and the episode was called infectious fungi. If you haven't listened to it, it was a really incredible episode with a lot of mind blowing facts about infectious fungi. So if you haven't tuned into that one yet, definitely give it a listen. If you want to be featured, like Eve, the cryptid and other people that we highlight on our show every week, Libra review, it really helps us out, it helps our rankings and helps people hear about the show and get inoculated with more fungal funds. So leave a review. We'll pick one lucky reviewer every week to highlight on our show. And if you want to check out our site, if you want to support us in any way, we don't take any third party ads and we don't have a Patreon or anything like that. So how you can support the show is going to our site mushroom revival.com. We have a whole line of functional mushroom products from tinctures, to capsules to powders gummies coming soon, and so many other great project project. So many other great products, and you can use the coupon code pod treat. For a surprise discount, we're not going to tell you how much it is. So put it in your car to find out we change it all the time.
And now we bring you Toby cares Toby Harris, thank you for joining Alex and I on a Monday morning to talk about the micro Raizel economy. We interviewed Suzanne smart and she spoke of your work. And we were immediately drawn to what you did. You watched your TED talk was fantastic. And we're so excited to have been able to arrange a conversation with you on this topic.
Thanks so much looking forward to it.
So your origin story we ask most researchers in the myco field, how they found their study and you know, just kind of their trajectory from being an interested scientist or artist or whoever you were into your niche today.
Yeah, it's always good to understand origin stories. I think my my work or interest on fungal networks started when I was 19. And it was in the tropical forests of Panama. I think I don't know maybe most of us, but by the time I was 19, I basically thought I had it all figured out. I loved the dirt. I hated shoes, and I had extreme wanderlust. So I was in college at the time. But yeah, I'd had enough of trying to learn about life from books and I wanted to become a biologist by doing and not not reading. So maybe it was naive, but the intention sort of to leave university landed me in the tropical forest, and Panama where I studied tropical roots and fungi. And actually it's the same island where Merlin Sheldrake who's I guess, beautiful book, we've all read a Lhasa study fungi. But I was there about Yeah, 15 years earlier. And this was the late 1990s. And we really had no idea what was going on with with fungi underground. And yeah, I think while the you know, the underground of the rainforest may seem unglamorous at the time, it really felt like this frontier, right? It kind It felt like the Wild West, it was so unknown. And everybody was concentrating on diversity above ground. But yeah, for me, the action has always been below ground, the things we can't see. And yeah, while I was, you know, simultaneously studying underground, my friends at the time were sort of interested in in understanding alternative economic systems like how small scale bartering works for examples. And there was this kind of Eureka moment when you're studying anything I think, is scientists talk about and especially when I was studying these mycorrhizal fungi. And, as you know, it's a it's a very strong trade symbiosis. And so I started to put these two things together, we knew that there was this exchange underground taking place between plant roots that were feeding the fungi carbon in the form of, of sugars. And, and now we know that it's there also feeding fats, you know, fats to the fungi. But at that time, we only thought it was just sugars. And in return, the fungi are growing out into the soil and foraging for phosphorus and nitrogen. But this is what we started to look at. I guess that's how I would say, we started to try to understand this barter system. And try to understand this trade in nature. And I think, yeah, bartering is kind of an interesting way to think about it. Because it's not always equal on both sides, you can have one partner kind of cheating the other. And we wanted to know what what happens. And can other partners tell when they're getting a good deal or not. And so that's, that's what, that's where it started all in Panama when I was 19.
And you bridge two, which seems like totally different topics, fungi and the market economy. And you do an amazing job and your TED talk, but I'm just curious, when did that all start for you to make that connection? And, you know, how did that research go over time?
Yeah, well, it started, I guess, when I when I left Panama. So really, I honestly, I really thought that I was going to be a biologist without getting my PhD. And I was quickly mistaken. I mean, as soon as I spent time in Panama with all these researchers, and realized that I really needed to get a PhD. I went and and I got my doctorate at University of California Davis, and I was studying with a professor named for Denison who is the author of a fantastic book called Darwinian agriculture. And it's a book everybody should read. And it was, at the time, we were really interested in trying to understand the evolution of symbiosis, trying to understand the evolution of how these types of partnerships evolve in nature, and asking why partnerships don't fall apart. So my PhD was really focused on trying to understand what we call cheating in nature, and how organisms Yeah, how they evolved strategies to benefit from being in a cooperative relationship, like you have with with fungi and plant roots. How they can benefit from being associated with cooperators without necessarily cooperating themselves. So what that the PhD project was on was also another below ground symbiosis. But this one was about nitrogen fixing bacteria called rhizobia. And I spent four years studying the partnership between legumes so your soy beans, you know, peas, all of the beans that we think of in the in the legume family, and the nitrogen fixing bacteria on the root system. So, so rhizobia are amazing. They take the atmosphere, nitrogen, and they can turn it into a form that's usable by plants. But like fungi and other kinds of organisms, they, they benefit if they can get carbon from the plants and not spend lots of energy fixing that nitrogen. So we started studying that relationship and trying to understand how plants can actually control the fitness, you know, the reproductive success of these bacteria on their root system. And yeah, we discovered something very cool that plants are very good at discriminating if you will, good symbionts from bats and Bionz. So we would effectively force the rhizobia to cheat and we did it in a very clever way by growing them in an argon atmosphere, so they couldn't turn nitrogen from the atmosphere into nitrogen for the plants. They couldn't turn argon into nitrogen. So basically, we forced them to cheat. And by doing so, we could study the response of the plant and see okay, do they know when they're being cheated? And, you know, Can you can you guess the? Yes. Yeah, so they're really good at it because it's natural selection right? and plants are under very strong selection pressure to be able to discriminate between good partners and bad partners. And, and what we found was that when the rhizobia failed to provide nutrients like nitrogen, that the the legumes, they actually cut off the oxygen supply to the bacteria, they suffocated them when they didn't provide nitrogen. And so yeah, this this, this work was published in Nature at the time, and it got a lot of press because it was sort of the first time where, you know, people were saying, oh, soy beans that have evolved ways to punish you know, these these nitrogen fixing bacteria that fail to provide resources. So I think that really started me on the Yeah, the road towards understanding these dynamics and other systems, especially between plants, and, and fungi, because there are some similarities with the rhizobia system. But there's also some very cool differences, which make it seem more like a market economy, if you will, then this, you know, top down host control, which is what we saw in the rhizobia. Symbiosis,
That's so incredible. So when you say a bad symbiosis is this just recognizing that the exchange between two organisms isn't like a one to one reciprocation? And there's that cheating going on? Where maybe they're getting counterfeit money? I'm I'm trying to project the economy system on this. But yeah, we I just that's an interesting term, but symbiote? And I just, could you define that a little more clearly?
Yeah, of course, yeah. So when we talk about, you know, a bad symbol. And then usually, what we mean is a less effective partnership, whereby the bacteria or the fungi, fails to provide the resource that it originally engaged with that host plant to provide. So you can imagine me cheating is such an amazing strategy, right? So imagine a root system that is simultaneously colonized by all kinds of different partnerships, right? They can be fungal, they can be bacterial. And it works really well if all of those partners are providing the exact same amount to the host plants. But in reality, that's not how it works. And if I was on that root system, and I knew it was very costly to provide resources, right, so for the rhizobia, they have to take, they have to use a lot of their energy, these carbon energy molecules called poly hydroxybutyrate, but it doesn't really matter what they're called, they need to use a lot of energy to break that bond of the nitrogen air. Basically, that's a very strong triple bond, it takes a lot of energy to break it. Same with my gradual fungi, they have to forage, they have to build this incredibly complex network to go and forage for that phosphorus. Now imagine if you could instead enter into the symbiosis. And everybody, all the other partners around you were providing those resources. But you were saving your energy, and you benefited from being on this very healthy host. So you're getting plenty of carbon, but you weren't paying the costs of cooperation. So in evolutionary theory, you know, we would, we would say that that strategy is predicted to spread across the population, because it's the one that provides the biggest fitness benefits, the ones that save the energy can reproduce. So that's what we talk when we, when we speak of a less effective or a cheating partner, it's one that is rather than spending all the energy providing that benefit, instead, it keeps the benefit and uses that for its own reproduction.
And going one step further, you talk about how fungi calculate trade deals, right? And, and vice versa, that the plants as well, they discriminate a good and bad trade partner, but also, you know, calculating how many nutrients to send to the fungi or vice versa, the fungi to that plant without a brain or, you know, I guess our understanding of consciousness and both the fungi and the plant, how do they calculate those trade deals? Right, and with no language that they can know verbal language that they can chat through and negotiate a trade deal. I'm just trying to understand, you know, from a million year perspective of natural selection, that I mean, it almost seems like consciousness. I'm just trying to wrap my head around how that actually works without language or, or our understanding of a language? It? Is there any insight on this? Or is this still an unknown that we're trying to figure out?
Yeah, I mean, I think we're trying to figure out the exact mechanisms of how it works. But the ability to discriminate between a good and a bad trade partner really doesn't require a central nervous system, it doesn't require a brain, right? These are sort of these are biological imperatives that organisms have to have. And so that's, that's really important. So if we want to talk about economics, so this is what what you know, I spent my TED talk talking about, you can use it as an analogy, right? You can say, okay, they trade as if they're in a market. But it's also a mathematical framework, right. And we can use it to analyze trade strategies in sort of predictive and quantitative manners. And that's really what we're doing. And so we're trying to understand what a fungus let's say, would do in a certain situation. And we use words like decision and calculate. But really, it's just down to biological mechanisms. And what it needs to do is be able to, in a certain interaction discriminate a good route from a bad route. And that really happens at the heart of the symbiosis, which is what we call the arbuscular. So this is the, you know, when we talk about one of the largest class of mycorrhizal fungi, they're called arbuscular mycorrhizal fungi also known as a MF, because it's such such a mouthful to say. But the arbuscular is an amazing structure, right. And that's where the, the fungus penetrates into the root cell and forms a very sort of, of complex structure that looks like a mini tree. And that's where the term actually comes from. And this is where the trade takes place. And so really, to understand these kinds of transactions, you need to understand what happens at that site, because that's where the carbon is being traded for the phosphorus. Now, when we talk about what it takes to be able to discriminate, it's definitely going to be a combination of factors. But really, the fundamental requirement to be a successful organism is is the ability to sense resources, right, just the way a root right will grow towards nutrients, or shoot will grow towards light, or even, let's say a small bacteria will adjust the way it swims to reach a resource pool, organisms need to sense resource gradients, and then allocate their energy based on those gradients. So really, I think the same thing is happening with with plants and fungi. You know, most of the magic takes place in these ephemeral structures called our best goal. But that's, that's where the plants and the fungi sort of negotiate how much resources are going to be traded.
So moving from that, another thing you talked about in your TED talk was manipulating the market and storing resources to lower supply space spaces or plans and increasing, there's an increasing demand in one area and vice versa. And this is a very common understanding of mycorrhizal mechanisms. So we've talked a little bit about those on other episodes. But I believe that you might have an interesting way of explaining the mechanism at least as much as we can. So where demands are higher? They, they charge more, right? They there's more effort that needs to be put into that exchange. But this is kind of what I'm deriving from your talk. Is there a theory that you have on this? Or how did you study this particular phenomenon?
Yeah, well, so this comes from the field of biological market theory. And it's, it's not a it's not a new theory, it was, you know, probably introduced by by sort of the, one of the fathers of biological market theory, whose name is Ronald mnoey. And originally, biological market theory was used to study interactions with primates, and grooming markets, for example. So a certain amount of grooming was exchanged for a certain amount of food. But as you know, let's say resources, the amount of food in the environment would go up, then the price of grooming would go down and they kept seeing this again and again. And and what's key about this is that you've at least in the in the microcosm mechanism is you've got a way for these types of markets to emerge, because you have to you have simultaneously two partners on either side of the interaction. So you've got multiple plants and And colonizing those plants are many, many different strains of mycorrhizal fungi. And that's kind of that's a basic requirement for a market dynamic to emerge is when you've got different partners, multiple different partners on either side of the interaction. And so the first kinds of experiments that we did was really just trying to mimic that in the lab. So we would set up these experiments in in vitro organ cultures. So these are, these are really crazy looking experimental setups, where you grew up, you grow a root system in a petri plate, and there's no photosynthetic top, the root system is able to take up what it needs for carbon from the media. But what that allows you to do, it allows you to manipulate again, the effectiveness or the co op the cooperativeness of the root system, because if you grow a root system in really high carbon, then it has more to give to the fungi. So we did a series of experiments where we attached fungi to to root systems that differed in their cooperativeness, basically, by growing them in higher low carbon conditions. And we found that the fungi were incredibly good at discriminating between the root systems that were giving them high amounts of carbon and those that were not. And actually, the more carbon we added that that triggered the fungi to, to give more resources to the root system. So again, when this this came out, in originally, original paper was in science in 2011. And, you know, there was lots of media attention, because it was like, these are the pioneers of the free market, right, the most ancient of 450 million year old symbiosis is that free market economy is the foundation of the free market economy. And of course, you know, there's just there's, you know, the media can go can go a little little, get excited with these kinds of things, but that the, you know, the basis was there that the, you know, we've tested both sides, whether plants could discriminate between fungi with our fungi could discriminate against plants, and that's really what you need for these type of market dynamics to, to emerge, we had to scale it up, we had to test it in whole plants move out of the, you know, the really sterile Lab System, test it in whole plants with say, with plants grown in the shade, and some in the sun, and whether fungi could allocate more resources to to those grown in the sun. And, you know, all of these dynamics start to emerge. But this is where it gets interesting, right. So that's just that's just discrimination. That's like the most basic Yeah, sort of fundamental trait that you need to be a good trader, you need to be able to tell a good, good partner from a bad partner. But manipulating the market was sort of the things that we've been looking at in the in the most recent years. And, and here, what we did was really try to understand the strategies, the actual trade strategies of the fungi themselves and how to decode them. And so what we would do is really set up these very largely manipulative experiments, where we would create a system where the fungus is faced with some sort of challenge, right, a plant that withholds carbon, or different amounts of resources in artificial landscapes. And we introduced a new technology where we could tag nutrients. So in this case, we were tagging phosphorus, which is one of the most important
nutrients that these fungi provide to their hosts, with these fluorescent nanoparticles called quantum dots. So you can basically tag a nutrient with these really bright fluorescent, very tiny, tiny particles, and follow them through the network so that we could actually start to understand the trade strategies of the fungi themselves. So you have to imagine that before this, there is no way to there was no way to understand a fungal strategy, right? How would you how would you even start to study how fungi trade with plants, unless you could, you know, visually or quantitatively follow those kinds of interactions. So so this technique really allowed us to start to take a step back and actually see the see the deals take place. And that's where we started to discover these new trade strategies, which is, I think, are some of the ones that you were hinting at, like what they do when they're faced with inequality, how they can artificially inflate the price. There's there's all kinds of things that have emerged in the last sort of five to six years of our of our research.
Yeah, this sounds like such an intricate mad scientist. experiments going on. And I really want to picture this. So when you were doing this in vitro in the sterile lab where you're growing these root systems and soil or liquid or even ag are seen as being done, how, what was your media of choice and why? And then with the fluorescent nanoparticles? Did you just blast them with like a gene gun kind of situation? How did you tag them? Exactly?
Yeah, so to understand the the setup, it was in Petri plates, so pretty big Petri plates. And so we used Agere, as the media, which, you know, obviously is clear. So that really helps us with visible visibility. So we could see that the tag nutrients made it into the network. And yeah, again, we've done some of the work with soil systems, they're very expensive experiments to buy quantum dots to add to soil. So again, you have to be very careful. And it's, it's a lot easier to do them in a very small setting, like a Petri plate. But in terms of, of creating the, these tagged nutrients, it's just analytical chemistry. It's It's beautiful, what you can do with chemistry, but basically, the basis of, of the resource was appetite. So rock appetite. It's a rock form of phosphates. And so through through chemical processes, we're able to create a kind of a shell on the outside of the of the phosphates with these nanoparticles. And then it looks I mean, it's, it's kind of thrown, you know, people into disarray, because it's quite hard to understand how the fungi are taking them up how they're moving them. And, and our most recent work looks like it's really endocytosis. So that's, that's really cool. fungi are amazing, what they can do is sort of envelop things. And so yeah, we can, we're just starting to get sort of the first understandings of how they're enveloping these huge sort of rock phosphate particles and then moving them through their, through their network.
I really appreciate the way that you choose to describe these scenarios and relating them to, you know, a market economy, I think, you know, we can get in trouble anthropomorphizing things in nature, but I think it really helps as a starting point to understand the initial concepts before we dive deeper. And we're, we've been talking a lot about plant fungal symbiosis. And, you know, you describe this as a trade deal. But there are, you know, organisms like ghost pipe, for example, that survive solely off stealing, you know, those nutrients in the middle of that trade deal. And you can, you can think of them like bank robbers or thieves. And, you know, in the human world, we have, you know, you can call the police and I know, they're certain plants, you know, when a pest comes, they can release a pheromone to, to attract the predator of that pest, almost like calling the cops on a robber or something like that. Do you know any mechanisms in which both or either the plant and the fungi protect against, you know, these thieves? These, you know, ghost pipe organisms stealing the nutrients in between the trade?
Yeah, I mean, this is some of the coolest work, I think right now. And again, it comes back to cheating. I mean, how amazing that there are these mega trophic plants is the word that we use that are able to tap into the fungal network and they don't photosynthesize, right? So instead of getting their carbon from from fixing co2 from the atmosphere, they just, they just tap into a mycorrhizal network and steal the carbon. How do they get away with it? Right? So this is a this is a very big open question right now. And what it what it tells us and we, you know, we've got some ideas for how something like that can happen. But you can imagine that these these ghost pants are most myco heterotrophs they never get so big, right? They're always sort of these small understory plants. And so one question we have is, is there sort of an absolute amount that you can get away with taking and then above a certain point where that drain starts to become even more, you know, noticeable to let's say, the fungi themselves? It's, you know, in the fungi themselves are actually getting the carbon from photosynthetic plants. So is the is the myco heterotrophs. Is it stealing from the fungi? Or is it stealing from the fungi that, you know, got the carbon from the plants? We do know that. You know, plants usually are pretty good at, for example, digesting our bus fuels, if they're not getting a certain amount of phosphorus. So that's very cool. So again, these are buskey Rules form. So this is not necessarily with the ghost pen with with a typical plant arbuscular mycorrhizal symbiosis you have the arbuscular forming, and if it's not providing enough phosphorus, and is that an absolute number, is it a relative number compared to what others in the root system are doing, we still don't know. But if it's not getting enough, it starts to digest the arbuscular, which is very costly for the, for the fungus, they degrade, let's say every seven days on their own. But if there's premature degradation, then this can be a very high carbon cost to the fungi. So they want to, you know, avoid being digested, if you will. Another really cool thing about these fungi is that they have nuclei that are floating around in the network, right? So the network is not divided by SEPTA. So it's an aseptic network, which means it's kind of like an open pipe system. And the nuclei are flowing through it. And they can also get up into the arbuscular. And so you can imagine that, for example, that the host plant may be able to control you know, which nuclei within that are more successful than others. So there's very cool work coming out from a scientist called Facilis, CoCoRaHS, who has been looking at these kinds of dynamics and how host plants may actually, you know, influence the the number of nuclei and the frequency of certain types of nuclei inside the network. So that's potentially one way that the plant can control, you know, who's succeeding and who isn't. So by digesting our bus schools, you know, maybe controlling the frequency of different nuclear types inside the network. And then from the fungal point of view, of course, that's that's quite interesting is like, Can we get a carbon quickly enough without giving phosphorus and so one of the things that we found, with the fungi, one of my favorite strategies that they do is they can grow out into the soil and take up lots of phosphorus. And then rather than immediately trade it with the host plant for whatever carbon they get, they can actually store it in their network, as is a specific form of phosphorus that the plant can't use, and it's being stored in the fungal network. So this is me imagine this is incredible strategy, right? Because the plant is no longer able to get the phosphorus. Neither are competing fungi. And so if it can hold on to those stores of phosphorus, until the plant really needs them, then there's a potential for getting a higher carbon to phosphorus ratio, you know, this is this is where price comes in again, is you know, how much is it worth at a certain time.
Again, so time is an important variable if it can take it up and store it. But space is another super important variable. So we did this one experiment, where we tried to look at resource inequality across a landscape. So basically, we took a fungal network, and we grew it across an artificial landscape of anger. And then we exposed it to varying levels of what we call the inequality in phosphorus availability. So if you were in a very equal environment, both sides of your network had the same amounts of phosphorus, so 5050 phosphorus. But as inequality increased, one side would have 70% of the phosphorus and the other would have 30% of the phosphorus or even more extreme, one side would have 90% of the phosphorus and the other would have 10% of the phosphorus. And then we saw how the fungi dealt with these conditions, right when it was exposed to this extreme inequality. And, yeah, and what we found was really interesting, right? So once we had this artificial landscape, we we tried to understand how the fungi traded. And, again, because of these nanoparticles, that fluoresced in different colors, those resource pools, one could be labeled green, and one could be labeled red. And so we could see where the different pools were moving across the network. And so what we found was that when a network was exposed to this inequality, it actually stimulated it to trade more. So we found that there was more trade going on with the host route. But I think even more interestingly was that it was done in a way where the fungus was able to get higher benefits because what it did was it it took the phosphorus from the really resource rich area, and rather than immediately in that same space, trade it with the plant And it moved it physically across the fungal network and traded it where resources were lower for the plant, and the plant was willing to pay more. So it got a better payoff by first transporting the resources, which is, you know, it can be an expensive process, right? It was it was active transport, we could tell that by looking at how fast it moved, for example, so it would spend energy to move the resources, but then trade it and get a much better price.
Unknown Speaker 35:28
There's, I'm curious, because there's a lot of talk. New, we've been talking a lot about the plant, fungal symbiosis. But I'm curious. Are there any examples of fungal fungal symbiosis? And and one thought that came to mind during this discussion was, Are there any instances that, you know, a fungus takes out a loan, for example, from another fungus, they want to make a trade with the plant, but they don't have much resources to get back. And the plant doesn't want to make it, you know, just anthropomorphizing the situation a little bit, but the plant doesn't want to make the deal, right? They're like, Oh, you're not going to give me enough in return. So the fungus has to make a get out of loan, right from another fungus to make that trade successful, and they have to pay interest or something like that. I don't know if there's an example that we can, you know, relate to alone in nature?
Yeah, yeah, we've been thinking about this a bit as well, because there is one process that we see. So you know, when we say fungus, the fungus that you know, we don't see this between different species of fungi. But if you have closely related fungi, then you see some very cool dynamics take place, with movement of, you know, sharing of resources and cytoplasm. So what fungi can do if they're closely related, so the same strain and sometimes different strains, you know, they can, they can fuse as well, but they, they actually can, can take their hyphae. And, and fuse together. And there's no fancy ways of saying this and studying it, but at its most basic is to two different hyphae that can fuse together and make these cross links, and then share the cytoplasm. And so we have been studying that, again, using these in vitro cultures, where we have, for example, two root systems, and a, what we call a common mycorrhizal network. So CMN, a network that is shared between them. And one of the things that we've been doing is varying the relatedness of the fungi in that network. And what we see is quite interesting, right? So if you're with a relative, and you can share the resources, then that changes the way that you trade those phosphorus resources, and it changes the way the phosphorus is shared between those two root systems. So yeah, you know, I don't know, whether it's alone, you know, the closer you are to a relative, it also almost becomes yourself, right? Like, if you share so many genes in common, you know, there's this very fine line between self and non self right. And so but what it's interesting as soon as you have two networks that are not relatives that are unrelated, you know, they they they end up allocating a lot of energy to competition, right to actually you know, in bacteria, they call it bacterial warfare, I'm not quite sure we're ready to use the term warfare when it's a fungal networks fighting against each other, but they interact in very interesting ways. And, and this isn't, this isn't a bad thing, right? I think, you know, again, talking about, you know, the language that we use to describe this field, you know, these these competition this competition between networks, it's it's it's not harmonious as many people think is everything underground is harmonious, it's definitely not harmonious, but it can be really beneficial to the host plant, because basically, the more that they're competing, the more they can underbid each other and their strategies definitely change when they're with relatives or non relatives and the the host plant itself, whether it's a tree or any kind of you know, herbaceous plant may benefit from that competition because they're competing to provide a resource to that plants. So again, I don't think we said this, but this is sort of key to understanding this whole field is that the the fungi, at least the arbuscular mycorrhizal ones are what we call obligate biotrophic. And that means they cannot survive without a host root. They need a host root to survive. They need the the carbon in the form of sugars and fats. And so when you have, you know, when you increase competition, you can make different predictions. So for example, competition could mean that they spend more time fighting each other and less time providing nutrients. But you also see situations where the competition actually stimulates, you know, the evolution of of different trade strategies whereby maybe one fungi is concentrating on getting nitrogen resources in that kind of niche space. And another fungi may, you know, concentrate on deep phosphorus or something like that. Right. So, so, yeah, I think that there's this kind of idea that's been going on in the, in the popular culture about all these interactions being harmonious. But actually, a lot of innovation can come from conflict, right? It's not a bad thing. It's not a bad thing to have competition. It's it's a tension between the plant and the fungus and the fungi and the fungi. It's this tension that I think really, you know, sparks innovation that allows them to evolve new traits and new strategies that ultimately can help our above ground ecosystems, you know, help plants. So for example, in farming systems, right, if you've just got a farming system that's been fungicide, and a farmer thinks, Okay, well, I'll let's inoculate it with a, you know, a one strain of fungi, that's going to be a very, very different dynamic in terms of nutrient uptake than you would if you had a very complex, diverse fungal network that was in an agricultural field.
And speaking of tension, and diversity of organisms, I have the hardest time even studying one organism and one kingdom. But I can't even imagine for you. I mean, you have to be an expert in plants and fungi. And trying to figure out that relationship seems incredibly hard. And I'm curious, you know, what has been the hardest part of your research? Have? You know, was there a specific scenario? I mean, you had a question that you just could not figure out. What was pulling your hair out? What was keeping you up at night? I'm just curious. What was the hardest part of you doing this research?
Yeah, I think the hardest part. That's it's a hard question. Parts. I mean, I wouldn't actually even these, these experiments. They're like achingly precise, like achingly precise. And sometimes, I mean, the inequality when it's so easy to talk, oh, you know, inequality stimulates trade. I think it took close to three years. You know, it's a long it's a long battle. It's a long, hard road. Because yeah, the challenge the thing that really kept my my, you know, that kept me from falling asleep at night. It's like, yeah, the analogy I like to use is like a, you know, having a table with like, the best poker players in the worlds, okay? Imagine you just like love poker, and you'd love to see people play poker. And they're really good at playing poker like, and the plants are a poker player on the fungi or poker player, you know, and they've been doing this for what I think the latest estimate is 475 million years. Like, they're pretty good at playing poker by this point, right? But all the experiments we had been doing is like you set you give them the cards, and then you turn off the lights, and you have no idea what's happening, right? And then at the end of the experiment, you have to harvest it, and you're like, somebody won, right? Right. But you can't see how they got there, the strategies that they use for how to get there. And so then you have to sort of work your way back and say, Okay, well, maybe this much went there, then they did this, you know, but it's, it's just guessing, you know, and so, the Nano the quantum dots, you know, that really helps in terms of, you know, shedding light, like, literally, on trying to understand how they trade, but we just need, we need up, we need a high throughput system, right there. Really, these experiments are very laborious, and we need to understand, yeah, at a larger scale, right? I'm doing just to reiterate, I'm doing experiments at a very small scale. What people are interested in is what's happening in forests and grasslands and like so scaling up what we see these tiny little networks to ecosystem level research. Right. So I think that's also a really big challenge. And, you know, we're trying to Yeah, we're trying to sort of scale across these these issues. One of the things that that's been amazing in our in our lab is we have a postdoc named Loretto. Galvez, who's coming from Chile, who is a biophysicist, and she built an imaging robot that is kind of blowing our minds, right? What it's doing is it's able to take images of fungal networks as They grow every four hours. And we're, it's really for the first time where we're dissecting the architecture of these networks, and where we can change the conditions, you know, add nutrients, or increased temperature, or just tiny little changes in the environment, perturb the fungus, you know, see how they respond. And so she, she's taking these images of how these complex networks grow. So we can, for the first time get at the topology of trade, right? We're really interested in trade, but like, how does that you know, you're asking how does it calculate? Right? That's exactly what we want to understand, how do fungi calculate across these very complex bodies. And so what Loretta has been able to do is, you know, get at understanding the architecture of the network. But then she attaches these these, she's able to kind of zoom in on certain parts of the network and study the flows. And so we're visualizing for the first time and quantifying these complex flows inside fungal networks. And I don't think anybody can watch these flows and not understand that there's nutrient, trillions of these nutrient rivers under our feet, right? It's kind of captures your imagination, because it goes in all of these different directions, right? It'll go one way, and then switch directions. And I don't know, we're really starting to see the unseen, right, we're still stuck in a lab. And, and that's frustrating. But you know, all the incredible people that I work with in my lab, like their dedication, their creativity, is allowing us to actually quantify and begin to figure out how does the fungus calculate where there's resources? Right? So if we change the conditions, how does that change the flows? Do those? Do they use those flows to help them realize what where resources? You know, what resources are aware? So I guess that's taking a hard thing and trying to make it easier. But yeah, what I want now is to have X ray vision and study these flows underground in real soil systems.
And do you think that is what's needed the most in this field is a way to really see what's going on, turn on the lights on the poker game and really see how the game is being played? Yeah,
you know, I do, I think that's a great way of summarizing it i because, to me, if you understand the strategies of these fungi, if you can kind of predict the way they're going to move resources, you have to imagine that, okay, sure. They're tiny decisions. But there's trillions upon trillions of these decisions going on simultaneously. And the end result of that is whether, you know, carbon is being sucked down into the network, how resources phosphorus is being moved across ecosystems, it scales up so fast, because these fungi are, you know, can be so abundant in ecosystems, that really tiny, tiny changes in the way they move the resources has enormous effects. So if we can study those at a small scale, and then yeah, begin to scale up across ecosystems, we can manipulate the the networks in ways that may allow us to store more carbon, right? So if there are certain plants that are associated with with giving more carbon down into the network, for example, how can you make like the, you know, healthy, fungal networks? What do what did those ecosystems look like? What do those flows look like? And how is it changing with increasing soil temperature? Right, we're just starting to look at that we increase the temperature in the lab, but it can change the way the flows move, that that keeps me up at night. That's scary, right? Just tiny increases in temperature is going to have really big effects. So yeah, I think, again, putting a light on it, I think, yeah, studying the flows will allow us then I think to make better ecosystem level predictions.
Have you seen the change of flows? Is it slower or less homogenous?
Well, it depends. So it seems like if you, you know, if you first increase the temperature, you know, it can lead to higher respiration, which can mean faster flows, you know, but following that over time, is the is the difficult part, right. And trying to see, you know, trying to make what we see in the lab. Yeah, how relevant is that to real soil systems? So again, it's yeah, it's too early to tell, I would say. So on
the flip side, what has been the biggest champagne popping point in your research? I mean, has there been a point of huge breakthrough? You had a whole team party? I mean, what was your proudest moment so far?
Yeah, I think really trying to understand again, this imaging robot has totally changed our lives. So I think for us, like scientifically, all of that work is is is going to be published soon. And that's really going to change the way that we start to study the flows and the topology of the network, because it's not one plate, right? It's like so much terabytes of data every month. I mean, more data than you can imagine. Right. So trying to, to it's the first time where we're just gathering that in one place and saying, Okay, this is probably the most ubiquitous symbiosis on Earth. And we still don't know how it forms networks or like what it does when it meets it, you know, a resource patch. So I think that, you know, that proud moment is, is on the horizon, I would say. But yeah, when you say the champagne moment, there was there was one, there's one time that the Dutch government I got an award for unfettered for performing unfettered science. I love that word so much, right? unfettered science. And they had a night that was like, the Dutch Oscars for scientist, and they had this this picture they had put it on it. I'm like a flag and it rolled down. Do you know what I mean? And, and it was my face. I've never, I mean, obviously, like, a scientist, you don't actually ever get celebrated like that. They're not movie stars. So that was the closest I ever came. And then they're like, Okay, everybody go, you know, it was really, really short. But it was that it was really fun to be Yeah, because people realize that this stuff is important. You know, it's, it's yeah, it's a good time to study fungi, I think. Amen.
Another fascinating phenomena within mycorrhizal networks that I've heard about is plant to plant communication through that network. And I don't know if you've studied any of this in the lab, or have anything to say about that. But I have heard, if a tree is diseased, or has some kind of environmental stressor, it can almost worn fellow trees that aren't connected to the root system, but do have that connection with the micro Raizel. System. Have you tried to simulate this in the lab? And what have you found?
Yeah, so this is this is really interesting work. And it's no, it's not done by our lab, a lot of it is done by a fantastic scientist, Dave Johnson, who is looking at these and, and one thing I think, is really important to think about, again, I'm always coming from a fungal point of view. So you know, take it, take it or leave it, right. But I think we need to think carefully about, you know, the terms that we use and what it means to have a signal or, or what we call a passive cue. So we definitely know that chemicals travel across networks, right, under stress conditions, as you said, so that's something that's that's very important. And it's incredible. What we don't know is if it's a directed signal are plants, are they warning each other? Or is it a passive cue, are they you know, that say, they say a plant experienced some kind of stress, like you and I can experience the same kind of thing. Lots happens to our chemistry, right, we upregulate all kinds of genes, adrenaline, and that produces, you know, secondary compounds that can, even if you say, even if they're leaking across the network, and other plants connected to the network, are ease dropping, and picking up on those cues, that can look like plants warning each other. So I think we just have to be very careful about the language of that, you know, from an evolutionary point of view, it's, it's a little bit tricky to understand why a plant would warn another plant that you know, that they're in competition with. But that doesn't mean that they're not communicating in a way that could be because of these passive cues traveling through the network. It would be super exciting if it was a directed signal. And if it was only to relatives, and right, there's so much more to discover. So it definitely could be happening. But yeah, from a fungal point of view, like what are they getting out of it? It's just interesting to think of it from like, a strict evolutionary point of view. And yeah, for us, our work hasn't so much focused on the signals across the network, but really the flows inside as, and we
yeah, as you said that I, you know, was thinking from the fungal point of view of, you know, what if it's the fungus being, you know, very selfish and saying, Hey, you better up your defenses, because I don't want to lose a trade partner. You know, and it's, instead of that directed signal from the plant, it's, it's really the, the fungus being like, hey, you know, there's, quote, unquote, you know, there's your friend over here, or your, your competition over here is, is dealing with this disease, like, I don't want this disease happening to you, or else, I lose my nutrient supply, right?
Yeah, exactly. So we had that that's a great way to think about it from a fungal point of view, if the fungus directly benefited from, you know, you just have to think, again, evolutionary biology, it's all just about costs and benefit, right? Does it cost anything for them to, you know, move these cues? Are there other fungi doing it? Can they, you know, if other fungi are doing it, can they not do it and still benefit from having a plant that's disease free, right? These are all the kinds of questions that we ask ourselves in this in this evolutionary lab. But yeah, if there's a direct benefit to the fungi of war, Earning a host plant, then you can imagine that trait could evolve, right? It's just about how much it costs and are other fungi doing it? And can you get away with not doing it? But I just like that conversation, right? It opens it up from a fungal point of view, and says, Okay, well, yeah, how does it work? Is it just passive and there's no cost or benefit to them at all that that could be. But again, we just have to ask, yeah, how could this evolve? And can we explain it in this in this world where you know, those that are putting energy into reproduction tend to tend to win.
So wonderful conversation. And another conversation I'd like to pose to any micro Raizel expert or interested scientist is on the topic of the difficulty of cultivating obligate mycorrhizal fungi. So, we already discussed how many of these fungi need carbon in a specific form via lipid or sugar. And, you know, they're not able to really fix and derive all of their nutrients from a nonliving substrate. So, the few times I've asked this, I've gotten a little bit of different responses. And now I'm on a mission to collect everybody's little perspective on this because I just think it, it will help us collectively kind of understand what's going on. But do you have any specific guesses or hypotheses as to why mycorrhizal fungi? mycorrhizal mushrooms are so hard to fruit? And if you know of any biochemical reasonings for this, you've found in the last few years?
Yeah, well, I definitely going to say what I know and what I don't know. And I think so at first you were asking about Mike Rizzo, fungi. So I thought, okay, I can answer this question from an arbuscular mycorrhizae point of view in terms of the Ecto mycorrhizal fungi, right, those are the ones that that tend to produce that you know, above ground mushrooms, then you're going to have to ask somebody else. Because, yeah, in terms, you know, the arbuscular mycorrhizae. See, they're also they're the ones that are the obligate biotrophic. So they're the ones that are super tricky to grow. But that's, yeah, it's not so much that they're hard to grow. They're hard to cultivate, I guess the distinction I would make. And so yeah, we, when we grow it, we you know, we have, we have rooms of cultures, right, that are always being being grown up on and we usually use these in vitro root organ cultures again, so these these plants with no photosynthetic top. And there's a new, there's a paper that came out just a few years ago, with some ideas that are really interesting in terms of the potential the small, tiny potential that you can cultivate micro arbuscular mycorrhizal fungi without a host. So I don't know if you've heard of that. But because these these fungi they receive, they receive certain fatty acids from plants, there was some work showing that if you added a certain kind of carbohydrate source, which is called Maya straight, you could get a fungal network to grow in the absence of a root system,
which is well that's crazy.
Because yeah, if you think about it, like at least from a trade perspective, I mean, for for so long, right? So for millions, hundreds of millions of years, these fungi have depended on plants for their their carbon and so it's really interesting. What does it trade network look like when it's no longer trading? Right? What is the what does the fungal network look like when it's just free growing without a host plant to provide phosphorus to and not get carbon from? So again, yeah, there's there's a few papers on this. It's it's still hard to do it you can't just add the carbohydrate source in a way you go from what I hear it's incredibly difficult still all very sterile and the things that you need to do for you know, good DIY fungal growing, but um, but that is one interesting thing I can I can add to the conversation.
Yeah, I have not heard of that yet. Thank you. It's really interesting. I'd love to get these papers. I'll try and find them. But I might have email you if I
Yeah, liras eyes, wrote up a little bit. I think you inspired her to start experimenting?
Yeah, definitely. It's fun to it's fun to try so I can we can Yeah, I send you the link and then people can can read the paper. Awesome.
So I've heard many instances of mycorrhizal symbiosis being crucial in in plants that are in extreme environments, right? Whether it's you know, in a acid, acidic environment or a desert, right with with not a lot of access to water, or a very cold conditioned environment. How do you Think that mycorrhizal fungi can help us with with our changing climate?
Yeah, this is this is I spend a lot of time thinking about this. And I really think that yeah, we've been looking at climate change mitigation. I don't know with our blinders on, right. This is especially clear after the recent cop 26, you know, where, again, planting of trees took center stage, I mean, virtually all conservation and restoration efforts are focused on what's happening above the soil. Right. But if we look at underground ecosystems, they store, I think the current number is like 75% of all terrestrial carbon, right, so three, there's storing three times more carbon that's found in living plants and animals combined. And so actually, together with with Collin April from ETH Zurich, we founded an organization called spun, which is the Society for the Protection of underground networks. And, and what it's doing is calling for immediate action to protect these networks, right to protect these underground ecosystems. It's a really science driven initiative to identify and map and preserve the Earth's underground fungal networks. I mean, as a scientist, you know, the more you stay in this field, I think, the more the more clear, it becomes that, you know, these really these guys are sort of the invisible ecosystem engineers, I think you said it very well, yourself outs where you, they're, they're drawing down carbon, they're protecting plants from all kinds of stressors, you know, they're, they're protecting them from heavy metal uptake, they're, you know, helping in terms of pollination, because they can increase the number of flowers on plants. You know, we haven't even started to look at the global numbers of how much phosphorus they take up. And so as scientists, it's it's clear to us that these are sort of the invisible ecosystem engineers like the, I don't know, even the coral reefs of the soil. But they're disappearing. Right. And this really has us worried. I think by by 2050, it saying that about 90% of the Earth's soil is going to be degraded. Wow. And these, yeah, these these underground ecosystems, they're really they've just been so absent from the conservation agenda. And yet, you know, fungal networks, they can take up, they can, you know, anywhere from like, 20, but up to 50%, of the living biomass of soils, right. So these are just, they are so fundamental to underground ecosystems. So I think anywhere from, you know, the conservative estimate is that about 5 billion tons of carbon, are flowing to arbuscular mycorrhizal fungal networks each year, so 5 billion tons. So, I think that's roughly equivalent to the amount of energy related carbon dioxide that the US emits every year. Right. So this is huge amount of carbon storage. So yeah, so we found it's fun to actually take a stand against this and say, we need to focus on underground ecosystems and map right, we need to figure out where are these networks? Where are the biodiversity hotspots? Where are the networks that are conserving the sequestering the most the most carbon underground, and you know, Mac them the way that scientists have mapped oceans, or even outer space. So that's really our big focus for the next next year.
And I would love to talk a bit more about this, because the day that this podcast will be released, you will be launching spun to the public. And I mean, what an incredible and critical initiative. And it's wonderful, you know, pushing for the education and the preservation and protection of these underground networks. If you could just briefly talk about what your initiatives exactly are with spawn and how we can all help aside from donations and spreading awareness.
Yeah, so our mission is really threefold. And the first one is, as I said, to map the fungal networks of planet Earth. And so what we're doing here is, is deploying what we call Micronauts, or underground astronauts, right. And these are basically people in their countries of origin that are going to sample DNA. And we're going to do this across continents. And this will allow us to really get the first idea of where these networks are growing. So, so far, we're working with an amazing database that was put together by global fungi. And that has about 10,000 observations. And so what these these initial 10,000 observations allow us to do is, is sort of start to make predictions about where we think the biodiversity hotspots are. And we then overlay that with footprints of of human expansion, right? So we have to try to identify, Okay, where do we need to get samples fast, because this is where we think the biodiversity hotspots are. But this is simultaneously, you know, area that we think is going to be converted to agriculture or urbanization. So, you know, there's there's really high interest areas in parts of India and in the Russian Tigra. And in Patagonia. So these are areas that we've identified using kind of Yeah, the first basis, these 10,000 observations, and then kind of machine learning to predict where we think these these networks are, are most in danger. And, and then what we do is that, you know, we start to preserve and protect those underground ecosystems. So this is still a far away off, but imagine sort of the first fungal conservation easement, right, where the biodiversity of the underground is valued to the, to the same degree, you know, if not more, but the same degree as the above ground. Right. So I think, you know, if we look at our current conservation plans, it fails to predict protect some of the most biodiverse ecosystems underground. So we really need to kind of have a switch in terms of Yeah, conservation priorities. And then the third bit is just about, you know, really cultivating the innovation space for mycorrhizal networks, right? How can we cultivate healthier, you know, high functioning networks, I think if we even put a fraction of the resources from other industries, you know, into harnessing fungal networks, we could, we could make huge progress across all kinds of managed eco managed landscapes like forestry and agriculture. So really pushing for innovation in this space. So that so yeah, so you know, we have a new website at spen dot Earth. And, you know, there's ideas for people how to protect their their local networks, like what you can do is just a person who maybe has some land, even even in cities, right? There's all kinds of things that people can do advocate for green roofs, what's so cool, some of these networks, they still spread by spores, and the spores are released into the air, and they need corridors to spread, right. So the more green roofs we have, for example, allows them to have these connections, corridors where they can reproduce and then spread again. So all kinds of things that people can do, I think, to support their own healthy networks. But yeah, of course, it's about advocation, and education, and mapping, become a you know, become an underground astronaut that's asking people
sign me up. And your website is gorgeous. Thank you for doing this. I'm super excited about this. And we will have to have you in any other member of the team back on once. You know, these maps start getting built out and some real traction and momentum is coming. We'd love to revisit any and everything that you guys have done in the future.
That's great. Yes, thanks so much.
Yeah, I love this episode, I think you're not only well studied and incredibly intelligent. But I think the way you articulate this information is very eloquent. And also creative, right? And accessible, right? relating it to market economies, relating these things, for people, everyday people to understand, I think that will be crucial for this fun project of, you know, the under things that we can't see, right? People, people don't really understand things that we can't see. And we're very visual society, right as Homo sapiens and and how, how can we access the dark, right? How can we turn the lights on in the poker game? I love that analogy, but I think will be crucial for the this initiative for conservation and protecting the biodiversity of our underground outer space. Right.
Exactly. And I do think that's such a great point. I'm so glad you mentioned it. Because I think this is where we need people from other disciplines, right? We need people who are who are writers, we need people who are artists, right? We need people to start understanding what's what's happening under our feet, right? 25% of all species live underground. But we don't see that we don't know what they're doing. And so, yeah, I you know, I'm American by birth, but now I'm in Amsterdam, and one of the things that the Dutch government is really progressive about is, is, you know, introducing artists into science labs. And so they fund programs, for example, where artists and residents come as part of my, my group and they actually, you know, are in lab meetings with us and, you know, make decisions and and we discuss, you know, findings, and it's really, you know, it's eye opening because it gives us a different perspective. It gives us a different kind of vision on things and stimulates creativity. And so again, as you say, Okay, yeah. How do you see the unseen? Yeah, I think having those different perspectives is very key. So I would definitely encourage people who, yeah, beyond scientists to get involved because that's the goal is for people to care about what's under their feet. And if people can visualize it, it helps so much.
Yeah, absolutely. The more disciplines the better, and the more productive and how our global consciousness will grow that way. So thanks for doing, what you're doing, and all the perseverance and hard work that came from your lab and from you personally. We're so honored to have this opportunity to speak with you.
Right, it was really it was really in a wonderful time. I enjoyed it very much. So thank you for doing all your work. I've been following your podcast and that's very impressive. So keep going.
Thanks, Toby. You too.
Okay. Until next time. Big thanks again to Toby make sure to check out spen the Society for the Protection of underground networks. This intelligence is vital and it's beautiful and deserves our attention. So thank you for tuning in and listening this far. And we appreciate you guys sharing the podcast sharing the fungal knowledge so so much, no idea how happy it makes us feel.
Tell your friend about this. Tell your mom, tell everybody. random person on the street how excited you are about mushrooms. As always, much love and discourse be with you