In this talk, Dr. Demetra Kandalepas, wetland ecologist who studies fungi, takes us on a thoughtful and revealing tour through the world of fungi, describing the various forms and their utility to the world around us.
Dr. Demetra Kandalepas – TEDxLSU TRANSCRIPT
I’m a wetland ecologist that studies fungi. When I tell people I study wetlands, they get it. They know why that’s important.
When I tell them I study fungi, I get a lot of blank stares. I get some awkward silences. Some people actually are compelled to tell me about the black mold they found in their bathroom. I remember someone trying to explain to me that their uncle had a fungus on their toe and “Okay, good times. Yeah, that’s good.”
So, I do get some people that tell me that they don’t understand why I would study such a thing. In the grand scheme of things with all the problems going on in the world, fungi really don’t matter. Well, that hurts a little bit.
But I’m here to tell you that fungi do matter.
And you probably all have a reason for either hating or loving fungi, or both. I’m here to tell you that you probably can’t even imagine the scope of what fungi do for you every day and what they could potentially do for you.
So, when you think of fungi, you probably think about some of your favorite fermented foods or beverages. Yeah, those are all really great. Some of you might be avid mushroom hunters, like I am.
Some of you might opt to grow your fungi in a dark closet in the house. That’s okay too. I don’t question that.
But for all the things you think about when you think about fungi, I’ll bet you don’t think about what they really do. You don’t really have a true appreciation yet for what they do for us.
You probably don’t think about the fact that without fungi, we’d probably be buried under mountains of plant debris, and maybe animal carcasses, and quite literally, a lot of shit. These things are incredible composters. They are the garbage disposals of Nature.
The fungus that you see right here, you probably recognize it as an oyster mushroom. It’s a great treat when I find it in nature; I love it. But it has a dual lifestyle. It grows on dead wood, and the reason it does that is because it needs the cellulose, which is a component of wood. It produces these potent enzymes that can only break down wood. Without them you couldn’t do that.
This fungus can only get sugar from cellulose. It still needs nutrients, so where is it going to get the nitrogen from? Well, it has developed a really intricate – I should say “ingenious” or maybe “sinister”- way of getting its nutrients. It forms these little microscopic rings, these “lassos” if you will.
And these microscopic rings are the perfect size for this microscopic parasite. It’s a little brown worm called a “nematode.” This little nematode, unsuspecting, comes along. It crawls through this little lasso, and as soon as the fungus detects it, it grabs onto it.
The worm tries to escape, but it can’t. And very promptly, the fungus devours it. So, fungi do a lot of things for us. But because of all these potent enzymes, they’ve also developed a reputation for being nuisances.
So, we consider them our competitors, if you will. And some are even more of a nuisance than others. There’s Uncle Joe’s toe. But they’re not all nuisances. There are some that are quite literally a miracle. I mean, they have saved lives. The metabolites that were found quite accidentally in this fungus right here called “cyclosporin” have enabled us to perform organ transplants. They suppress our T-cells, and so we don’t reject the organ. So that’s just one example of how amazing these things could be.
But we’ve only scratched the surface of what they can do, and how we can use them, and how Nature needs them.
So, we have to continue to study these things. They have a tremendous amount of diversity in color, in shapes and sizes, they’re beautiful! When you find them in Nature, you’re always mesmerized, am I right? They’re just gorgeous things. And they all have different functions.
They all grow in different substrates. But we’ve only, like I said, scratched the surface. We’ve only described 70,000 of these fungi. And I say “only” because it’s estimated that about five to eight million more exist.
So where is all this hidden diversity? Where are we going to find it? Certainly, you don’t look out the window and see everything covered in really pretty fungi. That’s not where we’re going to find it.
But in the last couple of decades, there’s been a great boom in research in mycology, and where, we think, most of the diversity’s going to come from is from plants. Fungi are so abundant in some plants, that if you take away all the plant tissue, you’ll be left with a skeleton or some sort of a ghost of the plant, and that will all be fungal tissue.
So these fungi are found in all organs, all parts of the plant. They’re found in the roots, in the stems and in leaves. They’ve developed a name for them. They call them “endophytes,” “endo” meaning in, and “phyte,” plant. They cause no symptoms of disease to their plant, so they’re known to be beneficial to the plant. They live there, invisible, happy, until something happens to the host.
Now, these fungi are so vast, there’re so many of them that I’ve chosen to study only the foliar endophytes. That’s enough, because these have shown to be hyper diverse. These things are so abundant that one could spend a lifetime exploring these fungi just in the leaves, and never really get anywhere, and still have several lifetimes to go.
How do they get there? Well, typically through air currents. They fall from other trees, other plants. They come in, they settle on the surface of the leaf, and if they can penetrate the cuticle and tolerate the plant’s chemistry, they get to stay. And they stay there happily.
So if you could all just take your fingers and do this, and look through that little hole, that’s about the area that one fungus can occupy in a leaf. So you can imagine how many you can cram inside a leaf. And they all coexist happily. They don’t fight; they don’t compete.
But when a competitor, a true competitor, comes in and tries to attack its host, well then there’s trouble. They put in place all these metabolites, all these enzymes, and they really do go to work to try to protect their host. But they also have a lot more benefits for their host.
We have found that fungi can not only protect their plant hosts from pathogens and herbivores, but we’ve also been able to show that they can induce drought resistance to their host, salinity resistance, flood resistance; they can tolerate low nutrient conditions.
So there are a lot of things that these fungi can do for their host just by sitting and living invisible inside their host.