How Mycorrhizal Fungi Sustain Life

Mycorrhizal fungi are critical to life on Earth. They have symbiotic relationships with surrounding plant life and are vital for the growth and health of forests. As we learn more about these subterranean networks, their function in the world more and more vital. We are in an era where we are losing our forests faster than we can understand (let alone protect) what we truly lose from deforestation.

Today on our podcast, we have the pleasure to be joined by Dr. Suzanne Simard, one most influential researchers on these fungi. Suzanne has largely contributed to the scientific acknowledgment to mycorrhizal ecology, as well as creating awareness about their critical role in local and global ecosystems.

Suzanne is sounding the alarm by proclaiming what we've discovered so far. We discuss what we do know about the vitality of mycorrhizal communities, current and predicted repercussions of disturbing them, and how we can support their restoration.

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More you can learn from this important episode:

  • A dive into Suzanne’s personal and professional journey 
  • Why old growth forests are imperative 
  • What our world would look if we did not have mycorrhizal fungi
  • The function of mycorrhizal communities in local and global ecosystems
  • Dark septate endophytic fungi and other forms of fungal symbiosis 
  • Suzanne’s book “Finding the Mother Tree”

 

Show notes:

Suzanne’s website: https://mothertreeproject.org/

Lessons from fungi - Toby Kiers Ted Talk: https://www.ted.com/talks/toby_kiers_lessons_from_fungi_on_markets_and_economics?language=en

TRANSCRIPT
Transcribed by https://otter.ai ** Subject to error
Alex 0:00
You My dear friends are listening to the mushroom revival podcast.

Lera 0:04
Today on the show we are joined by Dr. Suzanne Samar, who is one of the most if not the most influential researcher on mycorrhizal fungi. Suzanne has significantly contributed to the scientific acknowledgement of micro raizel ecology as well as creating awareness about their critical role in local and global ecosystems.

Alex 0:25
One could call this episode a Suzanne's and marred symbiosis. But before we get into it, the review of the week from Studio and K, my go to podcast Thank you. So both so much for your passion in and around the world of fungi. The topics you both present on this pot are so enlightening and fascinating. Thank you so much. If you want to be featured, you can leave a review and we'll pick one lucky review a week to feature on our show. If you want to support us, you can leave a review and also head over to our shop at mushroom revival, calm and get all of our wonderful mushroom goodies from supporting your energy, your immune system, focus the whole works partner with functional mushrooms for all that good stuff. And you can use a code pod treat for a surprise discount, we won't tell you what it is we're always changing it. keep you on your toes, little easter egg, a little surprise that you'll find out at checkout. And now drum roll we bring you Dr. Suzanne smart.

Lera 1:54
Dr. Suzanne smart. This is such a long awaited podcast. Welcome to the motion revival podcast. It's amazing that to me that we haven't covered mycorrhizal fungi in depth before and we're so excited to have you of all people here to discuss. So do you want to start by telling us your origin story? like who are you? And what led you to this niche science of mycorrhizal fungi?

Suzanne 2:18
Well, I, you know, I grew up in the forests of British Columbia, in the 1960s, which, you know, back then they were old growth forests, and my ancestors, my great grandfather, grandfather, my dad, my uncles, were all horse loggers. And so I grew up in that environment, watching all that and being part of the forests and part of sort of caring for the forest. And so, I eventually became a forester myself, but what I entered into was not stewardship of forests at all, it was, you know, exploitation of forests, as an industry, the forest industry. What as a young 19 year old, my first job, I remember being just like, aghast at the clear cutting. And so that got me on this track of trying to figure out what the heck is clear cutting doing to our ecosystems? And why did the forests that are going back look so different in knots not as healthy as the ones we started with?

Lera 3:25
And when you were introduced to this fields of mycology, did you were you in the forest wondering what kept the health of them here? And then you got interested in the soil and saw these little fluffy filamentous things? I mean, what, when did you first have an eye on the fungi? You know,

Unknown Speaker 3:44
I, when I was a lot, when I was a kid, I loved dirt. When I went to university, I took a lot of soils courses, so I got to understand them. And, you know, it was a natural for me. And of course, whenever I as a, when I eventually became a researcher a research silviculture list, I, you know, gravitated to all things in soil. And that included fungi. And I understood, you know, as I was working in these clear cuts and seeing the mortality of trees of young trees, that half of the problem were pathogens that had, you know, really we're expanding in following these kinds of practices where, you know, the old trees were cut through their stem through trunks there, there's roots were left in the ground, and these roots without any tree. On top of them, they're essentially dying root systems were very attractive to pathogenic fungi. And these pathogenic fungi would infect these big root systems, and then the seedlings would come in contact with them and they became infected. And so when I was, you know, tasked as a researcher to figure out what was going on I of course, You know, knew that there were these fungal pathogens and why were they out of balance and these new clear cuts. And that got me on this path of understanding that there are more than just pathogens. In the groups of fungi. There's also a group called mycorrhizal fungi. These are fungi that that actually helped trees grow. They, they colonize the roots of all of the trees all over the world, including all through the Pacific Northwest and the forests of Western Canada. And the fungi bring nutrients and water back to the tree and trade for photosynthate. And what I discovered is it Yeah, these mycorrhizal fungi were out of balance with the pathogenic fungi. So the micro rises, with clear cutting diversity dramatically dropped from 100 species per hectare to a handful, while the pathogens really took off. And so there was clearly this fungal community imbalance that had been introduced by this act of taking down the old trees.

Alex 6:03
And I, you know, when I talk to anyone about mycorrhizal fungi, your name comes up and your research comes up. I mean, you've had three TED Talks, and you've been, you know, featured in so many documentaries, I think the most recent one was fantastic fungi, where they did beautiful imagery of, of the mycorrhizal fungi underneath the soil, and then other documentaries as well, you're an author, and your research on mycorrhizal fungi is incredible. I'm curious, though, since it's probably been a long and rocky road, and not the easiest, was there a time during your studies or research that you wanted to pull your hair out, or, you know, just wanted to give up what was just like a really hard time. And if you could, there's probably a lot that was their hardest time and your research,

Suzanne 6:56
they're here, right? It's been an up and down rocky road, kind of like the pandemic, we get these outbreaks, and then these recedes, and but I think, after I published my paper in nature, and I was in my 30s, I was having children, and the blowback on that paper was more than I had ever experienced in my life, and I was getting critiques from all sides from the academic side, who were, you know, questioning whether, you know, my assertion that collaboration among trees was, you know, there at the same time as competition which had taken hold, and was really guiding all forest management product practices, whereas I was saying, Hey, wait a minute, you know, these trees are actually collaborating. And so I got a lot of pushback on that, both from you know, the academics who's who were on this, you know, path of, of Darwinism that was translated into ecology and management, that competition reigned supreme. And here, I was saying, No, you know, these things are equally important, if, you know, if not, you know, and, yeah, and so, and then, of course, the forest management side, this whole infrastructure of weeding out competitive plants, and even weeding out competitive trees, and, you know, favoring certain species diversity or lowered species diversity. It's incredible how far this focus on competition has reached and shaped forest management and agriculture, or any kind of Land Management Act, actually. So yeah, there was a lot at stake, and I was kind of on the receiving end of that for a while. And, you know, when I was, you know, having my children and dealing with this, I thought, you know, maybe it's easier to do something else. And I like that I dropped it for a while I, I started looking, you know, working more in the area of climate change and, and took a big rest. And then for about five years, I guess, and then I moved from the Forest Service to academia and picked it up again, and have been going ever since. But yeah, there was that period when I thought, ah, is it really worth it?

Alex 9:12
Well, I'm glad you stuck with it. And on the flip side, so what would you say is the proudest moment where you felt like you were, you know, just so enthusiastic about your work, you felt like this was a dream come true, and maybe it hasn't come yet. Maybe you're working behind the scenes on a really big project. And you know, in X amount of years, you will have that moment? Have you had that moment yet?

Suzanne 9:40
I've had so many moments. It's been great fun. I mean, in addition to these dips, there's been these incredibly rewarding and positive and embraced moment. So even as I when I published the nature, my paper in nature in 1997, the first paper They really got this going. Even as I was getting rocks thrown at me, I was also getting lots of, you know, positive media about it. I knew I'd hit a chord, even though I had to take this big rest. So So yeah, that was actually positive. And ultimately, that paper is what got me the academic job that I did at at the University of British Columbia, which is one of the top forestry schools in the world. And then another really big aha moment was when you know that one of the big criticisms at the time, back in the 1970s was, Well, what does this matter for plants? For trees? So these networks exist, who cares? Maybe they don't do anything. And so I got busy with my grad students and showed, you know, and demonstrated in our research that yes, it really is important to the survival and growth of new trees, new seedlings, and that as climate changes, as it gets hotter and drier, it becomes more and more important. So that was a big moment. And then I guess, I'm going to just describe one other big moment was, when we decided even among that there was still skepticism about, well, these networks, they don't really exist, they're not there. Maybe they're there, but they're not very extensive. And so I set about with my grad student, Kevin beiler, and we, and danjuro. And we mapped what the network looked like in an old growth forests. And that map was a huge aha moment, it's that's what made us realize that, you know, the big old trees were the big centers, the nucleus of the forest, joining all kinds of other reasons why there are two because of their biodiversity. In the fungi, the networks that they formed, the regeneration, they facilitate, and then all the other services, they provide, like carbon sequestration, and the biodiversity of lichens and mosses and so on. So I've taken that and now I've started this other project called the mother tree project, which is based on that idea that old trees are important in ecosystems, and trying to get us away from clear cut logging to leaving old trees behind so that they can actually, you know, bootstrap the next generation of trees. And we're finding that they really do so I'm having more aha moments, you know, now, it's so exciting really.

Alex 12:22
Once you get the momentum going, right, it's, I feel like, aha moments are at every corner. And especially with mycology, it's such a, you know, it's so underdeveloped, and there's so much more to learn. Compared to other sciences that are I feel like more built out. mycology is so new that every corner is just a new discovery, which is so exciting. Yeah. So if, if I might, if I may, I'm gonna give you a monumental task, which you just wrote an incredible book finding the mother tree? And if you could for our listeners who haven't read it yet, and don't know your work, could you give kind of a boil down almost 400 pages into kind of an elevator pitch on on what this book is about? And you know why this is exciting? Why mycorrhizal fungi is exciting for the newbie.

Suzanne 13:21
Yeah, so it kind of, I'm gonna start with why I wrote this book in the first place. You know, I've done I've been a scientist my whole life, I've published hundreds of articles on fungi and forests, the health of forests. And, and yet, it never really made a difference in forest policy and practices. All my research showed that biodiversity and leaving old trees and maintaining healthy soils matters to the resilience of forests. And yet, in Forest Practices that's not cared for, right, we still clear cut these old trees, we still you know, are have huge impacts on soils, we still are reducing biodiversity. And so and yet these things are the are the cornerstones of healthy ecosystems. And so I thought, I've got to get this out to the public because maybe they can push, you know, who the government, the industry, to make the changes that we need that we absolutely need, if we're going to deal with climate change, you know, even as we're, you know, dealing with these, um, you know, record breaking heat spells and fires, we're cutting down these forests as fast as we can. And so that was why I wrote the book to reach it. So everybody could read, read, understand, and then, you know, and then help. And so the end the story, it's a memoir, it starts showing the, my place in the forest as a kid growing up in these forests that This, these forests are in my blood and bones. And that this really was essential in, in myself as a scientist developing as a scientist. And then ultimately, the questions I asked, which were all about, how do we, how do these forests work? And how should we be stewarding them caring for them, so they continue to be these huge carbon sinks and places where species live and, and places where people can, can can get their livelihoods and enjoy and be healthy. And, and so I sort of trace that journey of learning about them as a kid to learning about them as a scientist, and then the fights that I had, with the Forest Service with the industry, trying to get them to change, and showing how difficult that was. And then, you know, finally pushing through and, and making more discoveries, and ultimately working with the Aboriginal people of Western Canada, who have this worldview that, you know, I realized, as I was speaking with them, that's what I had been trying to embrace all along that, you know, that everything is connected, that we're all in this and that what we do to our forests, you know, we do to ourselves, if we look after them, we look after ourselves, if we exploit them, we're exploiting our populations, as a human beings, ourselves. And so I, you know, I just wanted to bring this full story to people to say, we have to change how we're, you know, dealing with our environment, we have to be more regenerative people, we have to be more productive people not exploitive, if we want to change the tide on climate change. And so that was that was why I wrote the book that was basically the story it covers, you know, the science, but as I described, the science, I tell these stories, as they go hand in glove, that, you know, each discovery is a story unto itself, that's fun to read. There's drama, there's excitement, there's, there's discoveries, there's failures, there's joy, there's heartbreak, and I think it's everybody is life, I think most people can relate to these kinds of ups and downs in their lives. And it's Love, love, I think it's fun to read, and then you just absorb the science as you go along.

Lera 17:15
This book is definitely on my reading list. And thank you for giving some compressed wisdom into this book and getting it out to the public. Because, as you said, working with the forestry associations themselves isn't working. And I'm curious if you can just quickly tell us why like, what are they not willing to accept? Or maybe they are willing to accept it, but there's a monetary force that's preventing them from not clear cutting the old growth trees or any kind of thing that you can share with our listeners for like, you know, specific resistances that they have?

Suzanne 17:51
Yeah. Yeah, I mean, it does boil down to money, it boils down to being too greedy. And, and also, you know, for a long, long time, thinking that in Canada anyway, that here we had this vast old growth landscape at the, at the beginning of, you know, when colonization happened, and the Federation of Canada was formed. And so in the in the 1800s, it was sort of like the slow, small scale logging, there weren't very many people, it was people like my grandparents who were horse logging, taking one or two trees out of a forest to feed their families. And then as our population grew, you know, that we started, the government started to regulate forestry. But that regulation really meant to, you know, assign a cut level that would liquidate the old growth forests over 100 year period on the idea that 100 year old forest is all it needs. A forest only needs 100 years to get to get old enough to log again. And so we got on this, you know, this plan this plan, and it was enshrined in the law and the land was parceled out for cutting and big companies, big international corporations were were awarded these licenses to cut the forest. And so we've been on fulfilling that plan for the last 80 to 100 years. And and now here we are in my landscape in Canada, where we're all looking around going, Hey, wait a minute, you know, this is all clear cut. There's only in fact, you know, we've done the counting repeat scientists have done the counting in of the iconic old growth forests that are the big ones that live in Valley bottoms. The ones were that have the most carbon storage, the most biodiversity. There's only 3% of those left in British Columbia. And so now the public is going and you know, our, including our international laws, and our own laws are saying Hey, wait a minute, you know, we should be paying attention to species that are at risk. We should be full building our international agreements for climate change, we should be fulfilling our international agreements to protect our indigenous people. And yet, when we clear cut the landscape, we can't do any of that. And so, so people are rising up now, you know, as we're faced with the last watersheds of old growth forest, and I have to say, even today, at Faerie Creek in, in Victoria, near Victoria, on Vancouver Island, where I am right now. You know, people are chaining themselves to trees, they're, you know, they're, there's elders, there's young people, there's scientists, there's artists and poets, they're out there, trying to stop this exploitation of even these last old growth arches. And it's imperative that we succeed because we, the world needs these forests, we need them for the their ecological services. And if we don't look after them, it's going to have these positive feedbacks to global change. So yeah, it's it's an important it's an incredibly important fight. And it's a fight that is going on, not just here, but in the Amazon, in the tiger in in temperate forests around the world. So yeah,

Lera 21:10
yeah, I feel removing these mother trees in the forest is like removing vital organs from a body, you just cannot talk on for much longer. And a lot of that wisdom is thanks to you, and you being so public about this work. So I know we're creeping up on our time here. And we definitely want to get into some micro raizel science. So maybe we can do a bit of a not a speed round. But you know, just where we want to try and fit in a ton of questions for you. Because it's such a fascinating topic, Michael, logically speaking, I think, to help our listeners understand what mycorrhizal fungi are, what they do where they live. Maybe we can start with imagining a forest without that and what it would look like and maybe, yeah, what what do you think the conditions of our forests would look like without them,

Suzanne 22:08
we wouldn't have a forest. So you know, our trees around the world, most plants, in fact, there's only like five plant families that don't form associations with mycorrhizal fungi. So, all of the trees all over the world are obligate mutualists, with mycorrhizal fungi. So what that means is that the trees can't carry out their life cycle without entering into this relationship with the fungi. And the fungi also cannot carry out their life cycle without getting photosynthate from the trees. So the reason the trees can't survive as they can't get enough nutrients and water from the soil, because those things are tightly bound in soil particles and soil pores. And so the mycorrhizal fungi are an energetically efficient way to get at that. And the reason that we have that is because over millions of years, this these two organisms, the trees, and the fungi have co evolved. And they've co evolved since the beginning of when actually, plants started to moving from the ocean to land. And it's really one of the reasons that they could do that, in the earliest fossil records do show that there are mycorrhizal fungi in the earliest land plants. You can see the fungal Association right there. In the plant cells, you can see the front, the arbuscular mycorrhizal fungi forming little trees inside the, the cortical cells of the plants. And, and what those fungi are doing is they're, they're moving out into this, at that time would have been inhospitable rock, basically. And they're, you know, taking up minerals in water and delivering them to these little plants that could then use them to carry out their lifecycle. And so over time, these fungi have, you know, diverged many, many times, and there are now 1000s and 1000s, of species. And I think that one estimate, by saw was that we know about 55,000 species of fungi in the world. But, and we still don't know that much. We don't know much we're missing. Like, there's so many species, even when we do genomic analysis of soils in our forests, and BC, you know, we find new species every time. We really don't know what most of them do. But we do know that these trees wouldn't exist without them. So if the fungi were gone, let's say you know, and how do you how do the fungi disappear? Well, one way to to make a fungus community disappear is to clear cut the trees and take away the photosynthetic source. And so therefore the fungi that will die except for some of the resting spores. And so if there are no trees, and then they're left fallow for years, the fungi disappeared. And so then what comes in will a bunch of leads that don't actually need it. mycorrhizal fungi. So as I mentioned, there are about five plant families that don't need them. Well, you know, those are a lot of weedy species. So we'll see things like cheatgrass and you know, just all kinds of noxious weeds come in and replace our forests. That's not a very happy site, but that is what will happen.

Alex 25:18
And one of the most mind blowing things for me is that when I was learning about mycorrhizal fungi, as an early mycologist, I only learned about a singular interaction, right, between a fungus and one plant. But, you know, when I learned about your research about, you know, this interconnected system between many plants that really blew my mind, with, you know, fungi being almost like a, the Internet of all these plants in the forest, being able to send messages, say, you know, a plant gets aphid, or, or something like that they're able to send a message to another plant to increase its defenses. Or even send nutrients. And then, you know, I was just reading that, you found that for trees were able to send and trade nutrients between paperbark birch trees, which is amazing. I mean, it's, it's not even in the same species, they're able to trade nutrients with other plants of different species. I'm curious, how far does that extend? You know, can a oak tree trade nutrients with a tomato plant? I mean, how, what is the craziest reach that we've seen? between species?

Suzanne 26:42
Yeah, that's a great question. So, you know, in a, in a piece of land, let's see in a forest that's pretty healthy. We found there, just one, on average, up to about 100 species of Ecto mycorrhizal fungi. That's one group of fungus. So there are about five other groups, functional groups of mycorrhizal fungi. There are arbuscular mycorrhizal fungi which formed with the just thinking of trees in the Pacific Northwest. The cedars and maples in US formed this arbuscular mycorrhizal and they form a network unto themselves. And then the pine, ACA, the trees in the pine, ACA family form, eco micro rises, which there are hundreds of species. And then there are, you know, for other groups, there's the error code myco rises, which form associations with Eric kcaa. plants like sellouts and huckleberries. And Heather's, there's orchid myco rises, there are RB toId myco rises. And so there's, you know, there's all these functional groups, and within each of those, there's a number of species, and generally a plant will have fidelity to only one of those classes, right? Well, it will only form a mycorrhiza with an Ecto myco upon a say will only form a mycorrhiza was an Ecto mycorrhizal fungus not with an arbuscular mycorrhizal fungus, not with an Iroquois one, not with a with an orchid one, not with an arbitrary one. And so there, you can start to imagine that we have these sort of unique networks of those groups. So the huckleberries will be all hooked together, the arbuscular will all be hooked together, and then the peitc will all be hooked together. Now there are some species of plants that have fidelity to more than one class, or they can form associations with both Ecto and arbuscular. And there's not very many plants, but the willows, the populace are poplars, Eucalyptus, they can form these dual associations. And then there are some fungi that can actually form an error code mycorrhiza on a Huckleberry, for example, and an extra mycorrhiza on a pine tree, for example. And so then you start seeing these unique kind of links to from one functional group to another. And suddenly that network is not just a set of unique overlapping networks in the forest, but they actually can link into each other in through certain special plant species and certain special fungal species. They're, they're rare, but they do exist. So what is the funkiest relationship you could find? I don't know. I mean, honestly, I think in a forest like in a regular forest, you will see you know, pretty much everything linked to everything else, else through these unique nuclei as well as the big trees. So you know, most things will link together, but something that crazy that has happened that I think is cool, but scary, is that you know that you can even have these noxious weeds. Remember I said if we took away all the fungi, you'd have a field of noxious weeds. While some of these noxious weeds actually conform arbuscular micro rises, and they can tap into the existing network of an intact forest or grassland and basically invaded, suck the nutrients out of it and open it up and invade into it. So that that's kind of weird. It's kind of creepy. But these kind of strange liaisons can happen and they can be very destructive.

Lera 30:09
So when you say invade, how does that differ from a relationship to a plant? Because I know there's an exchange of nutrients but it's it almost sounds like a deal, you know, there, there's a handshake going on. But with this invasion, is it the same mechanism where the fungi is making its way up into the roots, but then the plant just sucks more than it is allowed or what? what is actually going on

Suzanne 30:33
there? You know, I'm not I don't completely know, because I haven't studied this exactly myself. But I've read it, I've read stories about it, or papers about it. But here's, here's the thing. So in a regular mycorrhizal Association, it is a market exchange between the plant and, and the fungus. And there has been scientists who have shown this Toby cures comes to mind, where, you know, the more nutrients the fungus provides the plant, the more photosynthesis, the plant provides in return. And so it's like a back and forth thing, it's like, you know, I give you $1, you give me $1 worth of goods, it's that it's that tight in these, in these cheating environments that we're talking about, there are some fungi that can actually work plants that can go in and cheat on the network, so they can actually start taking more than they then then they give, that can result in in sort of like a pathogen pathogenic relationship. You know, evolution generally takes care of these exploitive environment, relationships, but they can evolve. There are some, you know, cases that we I don't think that we understand very well, where, for example, there are some plants that don't, that don't have chlorophyll, we call them a killer awfulest plants. And so that means they don't have they don't produce photosynthate. And so, but they link into the networks of these older trees. So think of an orchid linked into, say, a large Douglas fir network, and it will exploit the carbon out of that network. Well, you know, scientists, I think, in this case, in a natural environment, we don't completely understand the services that that orchid might be providing in other ways to the ecosystem. So there's kind of a bit of a danger in really focusing in just on the tree in the network, because really, they're embedded in a larger ecological processes, where there's Polynesians, and there's other parities, as parasitism is going on, there's all kinds of interactions going on. So until you count all those up, you don't really know what the role of that orchid for example, is in the ecosystem. But you know, in these invaded in these sort of damaged ecosystems, so where, say we go, you know, humans go in and they exploit the forest and they leave an on forested weed field. In that case, you know, the whole balance, everything is off balance, right, the plants and the fungi are off balance, and then you you know, the interactions between those species are off balance, and this provides provides avenues for fungi to, they can even switch their lifestyle and go from an mycorrhizal to a pathogenic fungi, one of the the species that can do that is armillaria a story, it can be a mycorrhiza on that one point of its life. And then under the right conditions, if it's, you know, a lots of root exposure, lots of mortality in the trees, it will switch to becoming a pathogen, it can even become a saprotrophic. And so yeah, the fungi can be it can be very, you know, very flexible in that way. And so that, that kind of balance can't or unbalanced can really shift things around. And of course, the trees are more vulnerable to if they're stressed, then they're more at risk of being exploited by these odd relationships.

Lera 33:59
So I have a question in regards to endophytic fungi because these are also symbiotic fungi living with plans and myco rise Oh, I mean, Rise of equals root. But have you ever seen mycorrhizal species kind of make their way up into the plant and maybe into the leaves and be qualified as endophytic? And are any endophytic fungi? turned into mycorrhizal? I mean, yeah, what what can you say about these two versions of symbiosis?

Suzanne 34:27
Yeah, that's a great question. I actually don't know, which fungal species might be able to perform both. So I can't identify a species myself. One thing I do know, well, let me step back a little bit. So some of the endophytic fungi are what we call darks. uptake, fungi, and darks uptake fungi. We don't know that much about them. People have been, you know, sequencing them. So we know the DNA sequences. We, you know, some people have ascribed some functions to them as endophytes, for example, some maybe can fix nitrogen but but look for large part there, it's not known what they do. And at the same time, these darcs uptake, fungi can form mycorrhiza like structures in the roots of some plants. And again, you know, it's largely unknown, at least to my reading what they do. And so I would guess not knowing exactly if they're exactly the same species because those, there are many, I think sequences of dark and dark set date fungi that that have been identified. And I don't know of some, they're the same ones. But my guess is they would be endophyte and Mike arisal. But knowing the functions, I don't, you know, in those two different roles in the Plaza in those two different niches, I don't, I don't really know. But it's definitely a rich area for study. And definitely people have been seeing these overlaps, and these similarities in the end of fights and the mycorrhizae root tips. So not knowing more about it, I can just say that it's a fascinating, unexplored area that people need, you know, we'll be looking at and are looking at now.

Alex 36:12
And in the realm of symbiosis, you know, there's so many examples of fungal symbiosis between many kingdoms like animalia We, humans obviously have a symbiosis with fungi by growing them and in return, you know, they provide us food and functional ingredients. So then you know, how to answer leaf cutter ants cultivate them, and you know, for food. I'm curious, is there a kind of form of mycorrhizae or mycorrhizal relationship with bacteria in the soil? Do they have a symbiotic relationship? In terms of I've seen videos of mycelium forming these kind of highways for bacteria, and they kind of swim around around the mycelium? Is that happening with mycorrhizal fungi? And are they trading nutrients in a way?

Suzanne 37:08
Yeah, I mean, you know, think of the soil as a big food web. It's not just fungi, but there are, you know, millions of species down there. And, and they function as a food web. So think of, you know, you know, we have food, we know more about the food webs above ground where we have trophic levels where, you know, the base of the pyramid is, is the photosynthetic tree, and then you have got so it's the primary producer, and then there's herbivores and carnivores and top predators. Well, the same thing is going down below ground, with millions of species, including fungi and bacteria. And so in that foodweb, the job of that food bit one of the main jobs of that food web is to decompose material in the soil and, and in that process of decomposition to release the nutrients for uptake by plants, that that's a major function. So nitrogen cycling, phosphorus cycling, carbon cycling, all of that is driven by these below ground food webs. The fuel for the food web is the tree, the tree forests, mycorrhizal fungi the mycorrhizal fungi are full of carbon. So depending on the ecosystem, you're in the tree will will send 20 to 80% of its of his energy into that below ground mycelium and that mycelium then leaks out some of those extra days or accidents them out of the root tips out of the fungal tips. And those extra days or even the turnover, the death and turnover. The fungi provides carbon then for the bacteria, the nematodes, the the mites, the spiders, the centipedes, which are all eating each other. In the process of eating each other. They're excluding these this nutritious soup. So yes, definitely the myco rise, think of that network has kind of a leaky tube, where carbon is leaking out at the ends and the sides and the bacteria the whole soil foodweb along that micro rhizosphere is is having a feeding frenzy basically that's where they're getting their, their energy from. And so yeah, you know, that's very common, I painted a simple picture but the fungi the bacteria, for example, will be in constant communication about this offloading of, of energy and the presence of each other and they send signals back and forth to each other. So yeah, you should imagine this massive mycorrhizal network just loaded with bacteria, the entire surface area of the mycelium will be covered with with bacteria and then they will be you know, providing the food source for all these other creatures down the food chain. So yeah, and through that the development of all these communication pathways and understanding each other's presence, the roles they interact in an intimate way to drive these cycles.

Lera 40:00
thing that always amazed me about cultivating fungi is we find them in the wild where there's an incredible amount of diversity microbially speaking and insects, animals, plants, etc. But then we bring them into the lab and we give them sterile substrate. And that tends to work for a lot of fungi, we grow most of our fungi that way, most of our mushrooms with pasteurize or sterilized substrates, but there's obviously a preferred substrate for these species, you know, they like to have this community of organisms that's very difficult to replicate. So with that in mind, could you explain why mycorrhizal species are so difficult to grow? Me? What can we like? Take an example of an Amanita mushroom? Why can't we get this fungus to fruit? Even if we were to give it all the nutrients that its network needs? Is there some hormone that it gets from the plant that spikes the fruiting? or? Yeah, what what's missing from our cultivation practices?

Suzanne 41:04
Yeah, that's such a great question. So you know, mycorrhizal fungi, by definition are dependent on a living plant. And so that means, you know, to, to create that energy source in a greenhouse, or a lab or a farm, you have to look after the plant. And that's not easy to do always in, in in trees, you know, in forests, which is where we find most of our beautiful fungi were foraging on for for edible fungi happens, you know, where people go, and they pick mushrooms to, to eat the sheds, rouse the bullies, and so on. And without a healthy forest, you know, the, the trees can't provide the carbon, the photosynthesis to those mycelium to fruit. And so, so how do you replicate a healthy forest? Right? How do you do that in a laboratory or in a greenhouse, you can't really do that. And you're right, that, that it in the sense that, that it's more than just one tree and one plant and one fungus is more than one plant. And when arbuscular mycorrhizal fungi, for example, it's the whole forest community and the fungi. And so in that forest community is benefiting from the diversity of fungi in the, in the soil, from the diversity of plants above ground from the diversity of all the animals that that carry out, you know, the pollination, the seed dispersal, you know, all these things go together. And when we start, you know, if we try to pick apart that system and say, Oh, just one plant one fungus, it's not going to work. And you pointed out, maybe there's some other things that are being exchanged between the plant and the fungus. In addition, you know, in addition to this community effect, and, you know, I don't know a lot about that, but I do know that, you know, in our work with, you know, with injured trees, and what they, how they transmit information to their neighbors, that these are carbon based molecules. They're not photosynthate. They're, they're not amino acids. There are other information molecules that include things like hormones and enzymes. And so yeah, these things are also being moved around through the mycorrhizal network. Even herbicides can be moved around in my car rental network, for Pete's sakes. It's quite amazing. But yeah, we, but fundamentally, in order for the function of that mycorrhiza to happen with all these different compounds moving back and forth between the two partners in this mutualism, they both need healthy communities. They need help, we need healthy forests we need to and that means we also need healthy fungal communities and the whole healthy soil food web as well.

Alex 43:50
There's so many applications for mycorrhizal fungi and they're, they're incredible and just talking to you on our show. I mean, it's been so fascinating. There's so many topics I want to get into. I mean, I've heard researchers using mycorrhizal fungi in connection to plants to mine gold and abandoned gold mines you know, people cleaning up heavy metal waterways or soil to help clean or soils even even conditions where mycorrhizal fungi hold up to 70% of carbon in our soils and how they're crucial, like you just put for so many plants, their survival, and for plants in our forests and ecosystems and, and even in really harsh environments, like plants to survive in the desert or Arctic environments. I mean, this is so crucial for helping us and these are the diversity of organisms in response to climate change. So all that being said, all the amazing things, all the amazing research into mycorrhizal fungi. What research Do you thing is missing and what do you what research would you like to see done most in this field

Suzanne 45:07
you know, there's so many things that we don't understand. And so to pick out a few things is is is hard but for me I'm so I'm a forest ecologist and I study for us and one of the things that I really am passionate about right now and so worried is that we're losing our old growth forests so quickly in the tropics in the boreal in the temperate forests. Right now I'm in Victoria because we're down to our last 3% of iconic old growth forests and trying to stop the the logging of those old growth forests and so yeah, I mean in with the forest when the forest goes so do go go rare and endangered fungi and lichens and we will never get those back and so I feel like you know, there's an urgent need to apply the science we do know to to what we're doing to our forests, because if we don't do this if we lose these forests, we're not going to have much in our favor as we try to deal with climate change they're what they are what soaks up co2 and so I would like to see an emphasis on the ecological value understanding more the ecological value of keeping these old forests I guess, and and also, you know, the ecological value of keeping rare and endangered fungi of which we know so little about I think we also I would like to see more work on not just keeping the old forests intact but to recover the forests that have been damaged and which fungi can we do we need to introduce which species Do we need to introduce? Or or even just will they come back on their own? So that's one thing I also am concerned about as climate changes the velocity of climate changes so fast that trees are going to need to migrate do the fungi need to migrate to do we need to help them do that as even as we're assisting migration of plants? Do they go hand in hand? We don't know anything about that. And then of course the basic functionality you know well, what species don't we know about and then what would they do I mean we have we have such a small understanding of this so these are huge areas they're important right that I would really like to see the science being applied to saving our planet really we know a lot we then we need to know a lot more but we know enough to do a better job already so

Alex 47:37
Absolutely. Well thank you so much. This has been mind blowing and gets me inspired to get out into the forest and interact with organisms and and be proactive about saving our old growth forests and our forests period.

Lera 47:54
Yeah, thank you for this honestly very critical education that I hope we all understand as a global conscious before we lose these forests, because that would be heartbreaking.

Suzanne 48:05
Thank you so much. This has been a pleasure.

Lera 48:08
Once again, Big thanks to Suzanne smart This is truly profound work and to be honest, I'm not sure how we can be most proactive in protecting our planet. But I do know that awareness is a critical beginning step. So thanks to you for listening and for being part of this podcast. We honestly could not do it without your support and continued participation.

Alex 48:30
It's almost like we are the trees and are you guys are lovely listeners are like the fungus. You guys mean so much to us. And thank you for being there for us. As always, much love. May the spores be with you.