Become a Creator today!Start creating today - Share your story with the world!
Start for free
00:00:00
00:00:01
19 Leonora Bittleston: The world on a leaf
0 Plays2 seconds ago
Biologist Dr Leonora Bittleston takes us into the mysterious world of the phyllosphere – the micro world upon leaf and plant surfaces. We discuss her research on plant-microbe interactions, looking at case studies of the sage brush steppe ecosystem and the fascinating miniature worlds of carnivorous pitcher plants. She shares how even the smallest organisms on our planet can be a force of nature.
Bio:
Leonora Bittleston is an Associate Professor at Boise State University. She is fascinated by the complex interactions that form between very different kinds of organisms, and among microbes and plants in particular. Her research aims to learn more about life on our planet, taking into account the interconnectedness of ecosystem processes, communities, and species. Previously, Leonora was a James S. McDonnell Postdoctoral Fellow in Complex Systems at MIT. She earned her PhD from the Department of Organismic and Evolutionary Biology at Harvard University and her BS from U.C. Berkeley.
Hosted and produced by Catherine Polcz with music by Carl Didur.
Recommended
Transcript
Introduction to Plant Kingdom
00:00:07
Speaker
I'm Katherine Poults, and this is Plant Kingdom. Plant Kingdom is a conversation series about awe and the sublime in nature and environment, featuring scientists, artists, researchers, and writers.
00:00:19
Speaker
We release a conversation each month and hear from people who have an intimacy with nature. We discuss their work, stories, and reflections from the field.
Exploring the Phylosphere with Dr. Leonora Biddleston
00:00:28
Speaker
Today's conversation is with researcher Dr. Leonora Biddleston.
00:00:33
Speaker
We explore the mysterious world of the phylosphere, the micro world upon leaf and plant surfaces. Leonora's research is on plant-microbe interactions, specializing in both the sagebrush steppe ecosystem in the western United States and the fascinating miniature world of carnivorous pitcher plants.
00:00:53
Speaker
She shares how even the smallest organisms on our planet can be a force of nature. Here's our conversation.
00:01:03
Speaker
hi Leonora, thank you so much for speaking with me today. Really looking forward to jumping into all things microbes and plants. Can you just start us off and give us a brief introduction to yourself and your research? Sure.
00:01:17
Speaker
Yes, of course. I'm really happy to be here. My name is Leonora Biddleston, and I'm an associate professor in the biology department at Boise State University. And the research that I do mainly focuses on plant-microbe interactions and also community ecology, which is thinking about how different organisms interact with each other, how they come together, and sort of how they affect ecosystems.
00:01:42
Speaker
Amazing. And community ecology, guess I was introduced to it at a much larger scale than the microbes. So I'm really curious and looking forward to looking at it, putting a big magnifying lens to it and looking at it at the more minute scale. And you've been working with microbes for a while. It's not, I guess, your first interest in your career. You started working with insects, I believe. But what compels you or interests you about microbes? How did you really get into them? Yeah, I found them so fascinating because they're so small, but so abundant and so diverse. You know, we can't even see them, but they're everywhere. They're all over the world and they have these huge outsized effects on the world. They're so small, but then they have these really large impacts. and They associate with pretty much every kind of plant and animal species. They're in all ecosystems. They can have either really beneficial or really negative effects on their hosts. And even the way that they can drive these large ecosystem processes, like how nutrients move through the world, even the weather, you know, causing precipitation to form. And so I think I was, yeah, I was so excited about them because they're this this huge group that has these large capabilities, but they're still very mysterious. We still don't know that much about them. And they're so tiny. Yeah. So there's so many questions you can ask.
00:03:07
Speaker
How do they change? How do they cause precipitation? Well, you have these, either these like ice nucleating proteins that they make or They serve almost like, you know, a pollen grain can serve as like a little thing that can make water condense around it. So you can, they can help rain or with snow.
00:03:27
Speaker
Fascinating. And we'll be talking about microbes just a bit.
The Role of Microbes in Ecosystems
00:03:31
Speaker
But to get us started, I thought it would be helpful to do a bit of microbes 101 and remind me what what we're even talking about when we talk about out microbes, because there are a few different organisms, right? What what defines a microbe?
00:03:49
Speaker
Yeah, it's it's mostly size. So something's considered a microbe if it's on kind of that micro scale and you can't see it with the naked eye. Okay.
00:04:00
Speaker
And so there's a few different evolutionary lineages. Is that right? What's the major Yeah. Yeah, so being a microbe doesn't mean that you're related more closely to other microbes than to other things.
00:04:13
Speaker
ah Bacteria make up one evolutionary group. Fungi are in another, although fungi are a little weird because some are micro, but some are clearly macro, right? There's a lot of mushrooms that we can definitely see. But then there's all these yeasts and a lot of fungi can live both in the macro and micro worlds. And then and other groups include things like protists, like algae or ciliates, other little eukaryotes that can live in water or soil. And then also most people include viruses as microbes as well.
00:04:47
Speaker
Wow, it's a very different organism. And the bacteria, the fungi, a lot of these organisms are really ancient, right? How long have they been What are the kind of the earliest ones?
00:05:02
Speaker
Yeah, bacteria are very ancient. So probably the first ones that people think they found were over 3 billion years old. So like approaching the age of the earth, you know, really definitely the earliest organisms on earth. And then some of the other groups are a bit more recent, but definitely were around before um plants and animals. So very long time ago.
00:05:25
Speaker
Very long time ago. And just, I guess, connecting back to how you were saying, about the massive role they have in shape in shaping our environments today. They really, they're the their oldest organisms. They've played a huge role in terraforming, creating the conditions of Earth today, two haven't they, in that time? Yeah. Microbes are are what came together to form the first organism. eukaryotic cells, right? So different kinds of bacteria and archaea are probably what are behind the eukaryotes that we know today. So all the plants and animals, and they, you know, they're everywhere. And they really were, they they form this kind of like evolutionary background of everything, right? They've come together in these symbioses in different ways to allow plants to move on to land and things like that. So They really underpin a lot of the world as we know it today. They are on every continent. We know they've had a lot of time to move around. They're everywhere. Yeah, they're everywhere. so even in environments like acid mine drainage sites, which are probably some of the most extreme and toxic environments, you'll still find some microbes that can live in that environment. So they really are able to live in all kinds of different contexts.
00:06:49
Speaker
Is it even possible to define or describe the role of microbes in ecology? i feel like ecology has spend so many decades and hundreds of years thinking about plants and animals and the visible fungi.
Microbial Diversity and Misconceptions
00:07:07
Speaker
What is what is the role of the microbes in our in our ecosystems?
00:07:12
Speaker
It can be hard to know, like for a particular microbe, exactly what it's doing because they're hard to see, right? We can't just watch their behavior. But we definitely know that microbes are involved in some of the most basic and essential parts of our ecosystems because a lot of them...
00:07:29
Speaker
like a lot of bacteria are photosynthetic, right? Like plants are. So they are actually building the biomass from things like CO2 and sunlight that makes up our world. And then, and then a lot of bacteria and a lot of fungi are also decomposers. Like they're really involved in breaking things down and,
00:07:50
Speaker
taking organic matter from dead things and making it usable again, cycling those nutrients and allowing other organisms to use them again. So they're really part of these cyclical patterns with within our Earth.
00:08:03
Speaker
Do we really have a sense of their biodiversity or how many, i don't know, is species the right word, how many there are? yeah I mean, I saw an estimate that said that maybe we've only formally described less than 1% of the bacterial species that exist. So there's this vast diversity and, you know, we're learning more about it every day, but there's still so much that we don't know about who they are and what they do.
00:08:31
Speaker
DNA and ah RNA analyses are really helping us a lot with being able to figure out who's there, because a lot of them we can't culture. We don't know how to get them to grow on our own terms. And so it's still this very big, open, mysterious world. But I do feel like we're learning more and more every day. And we now have a lot more tools to be able to really properly study them. And tell me if this is totally wrong. I i remember hearing, but it was something like that is a spoonful of soil has as many microbes as like stars in the universe something.
00:09:06
Speaker
it that Is that a thing? Yeah, I mean, I don't know exactly. i don't remember the exact connection. But, you know, you could have like something like 10 to maybe 10 to the ninth or something microbes in one small a spoonful of soil. Soil can have so many microbes in it. It is this really dense world where they're so small. And it's hard for us to think that you could have that many, right?
00:09:33
Speaker
it's It's really vast. Stretches our imagination lots. One more 101 before we really delve into some of the systems that you you work in. Are there common misunderstandings or mischaracterizations of microbes that you that you want to set straight for us?
00:09:51
Speaker
I think the most common one that I come across, and and this is changing, which is good, but it's just that microbes are bad, right? So people... The first thing people usually think about when they think about microbes is is that they cause disease and they're bad. They make us sick, but that's really only a tiny, tiny fraction of the microbes that exist, right? Most have no effect or even beneficial effects on us in our world. And so So I think we're moving away from that idea as we learn more about microbiomes. But but that's the biggest one is just people being like, eh, microbes, like, I don't want any to touch me. And you're like, they're already covering you. You're fine. and They're digesting for you. They're doing all this for you.
00:10:35
Speaker
Yeah. They protect your skin from getting other diseases, you know, they're they're yeah protecting. And I guess through diseases, that's maybe how they were most visible to us.
00:10:47
Speaker
Yeah, it was easiest to study them when we were looking for these agents of disease, right? So then you could culture it and figure out, you know, that's what's causing this plant to die. That's what's causing this person to get sick. Yeah, it was harder to to really understand all the ones that weren't having symptoms, right? That weren't causing negative symptoms.
Sagebrush and Its Microbial Environment
00:11:08
Speaker
Now to get into plant and microbe interactions, a really fascinating field. There are two systems that you work in that we'll talk about today. The first one i want to talk to you is close to home, close to where you you work in in Boise and is the sagebrush. Can you describe the significance of the sagebrush plant and its habitats?
00:11:33
Speaker
Yeah, yeah. it's Big sagebrush is considered the foundation plant of the sagebrush steppe ecosystem, which is the largest rangeland ecosystem in the US. So it it really covers a lot of the particularly the Western US from, you know, Montana, Wyoming, Utah, Nevada, Idaho, Washington, Oregon, even down into Arizona, California. So it's it's a ah vast ecosystem and it's considered this foundation species because it's usually the most visible sort of shrub within that
00:12:09
Speaker
system, but also it's a really important food source for some endangered animals like pygmy rabbits and sage grouse. And it can also act as a nurse plant to support the growth of other native plant species. So it kind of having sagebrush there is really important for that whole ecosystem to exist. And it it's threatened. So even though it's very common, there's estimates that only about 50% of what used to exist still exists now. So It doesn't regenerate well after fire. And and yeah, we're losing a lot of the sagebrush.
00:12:44
Speaker
And the sagebrush, it's Artemisia is the genus. It's an Asteraceae. Yeah. Yes, that's right. Yeah. so um And there's multiple species of sagebrush. So the one that I work with mostly is Artemisia tridentata. There's also subspecies of it. And and there's other species like Artemisia californica is the one that you find in California. So yeah, there's various different species.
00:13:08
Speaker
Amazing. And are they shrubby? Are they woody or herbaceous in that? They're shrubs. Yeah, they're they're shrubs that, you know, can kind of be anywhere from maybe like knee high to even over your head. And they have kind of a woody woody stem that can get reasonably big.
00:13:27
Speaker
And you you mentioned... nurse plant When I heard nurse plant, I pictured a nurse log, the decaying logs that all the moss are growing on, seedlings might sprout of out of it, that the object creates a lot of life in the forest. Is a nurse plant kind of the same thing? What is what is a nurse plant?
00:13:47
Speaker
Yeah, yeah, it's kind of similar. So the sagebrush step usually doesn't have much shade, and it has a lot of wind, and it can be really dry. So it's kind of often these like high desert environments. So people have found that sagebrush has this very deep, deep, deep tap roots. And so they can actually bring water up to the surface from way below where other plants might be able to bring it up. And that actually increases just the amount of water that is around the surface level. um It also probably is shading a lot of seedlings and allowing them to grow because of the shade or because of protection from high winds and things like that. So, It's kind of acting as this modifier of the stresses of the environment that helps other plants grow.
00:14:36
Speaker
i spoke to this researcher who studied Antarctic moss, and she had this beautiful way of talking about the moss beds as being miniature, ancient, old-growth forests, just looking at the complexity of ecosystems that lived on them. And it's kind of a similar thing.
00:14:57
Speaker
situation Maybe not old growth that will get into. Yeah, all of the creatures that the sagebrush supports. You have this beautiful term in your research or in this in this field, the phyllosphere. Can you tell us what the phyllosphere is Yeah, yeah. Yeah, it comes from, mean, it's a Greek word, I guess it comes from Greek. Philo is leaf and sphere is like domain or environment. So the sort of literal translation of it is like the environment of a leaf. But currently researchers use it to mean all the above ground parts of a plant along with the microbes that colonize that environment. So it's kind of like that habitat that
00:15:42
Speaker
the above ground parts of a plant make up and yeah, and those organisms that colonize it. I love that the world on a plant or on a leaf. And i guess what kind of organisms have you found make their home on the sagebrush leaves? How many different species might you find? You know, sagebrush, I guess one thing I didn't mention about it is that it produces a lot of interesting chemicals. So if you've walked in the sagebrush step, if you've gone for a hike in that environment, you'll probably know that has this amazing smell. If you rub a few of the leaves, you know, it leaves this wonderful smell on your hands. And a lot of those chemicals are actually antimicrobial.
00:16:25
Speaker
And so when we first started doing this research, nobody else had looked into like, what are the microbes that live on sagefish leaves that live with this, the above ground parts of this plant. And so we weren't actually sure if we would find a lot of microbes living there because it does have these antimicrobial properties in a lot of the chemistry that's there. But we did. We found, we cultured from these leaves. We found quite a lot of different microbes growing on them.
00:16:49
Speaker
We found a lot of fungal yeasts as well as some bacteria. We think maybe fungi are particularly good at colonizing this environment because they can survive. some harsh environments, and leaf surfaces can be quite dry and experience a lot of UV in this habitat. And we found a lot of fungi that are dark brown or black that actually contain melanin, just like we have melanin um that protects our skin from UV and it protects those fungi from UV damage too, which I think is so cool. Wow, how ancient melanin is. Yeah, right? It's neat to think about those connections between ourselves and the microbes around us.
00:17:30
Speaker
You had also asked like how many might there be? um So when we culture from a leaf, you know, sometimes we'll find maybe like 12 different species on a leaf, something around there, but they probably, there might even be more that we can't culture and that we might find when we do a DNA analysis. And there's many more than that on a whole plant. And then in a whole, you know, stand of plants and then across a whole ecosystem, you'll find many, many, many more than that.
00:17:58
Speaker
Yeah, wow. So each plant would have its own just possibly distinctive or differentiated communities, or they all have a they're a different history of being on that plant.
00:18:10
Speaker
Yeah, yeah. And one of the things we found is that they change over time, which I think is really cool. So we did a project where We sampled from the same six plants. We sampled leaves from those plants across a full year. And we did both culturing and DNA analysis.
00:18:27
Speaker
And we found that the microbes that are more abundant in summer might be different than the ones that are thriving in winter. So it's different seasonally. And it also changes with the age of a leaf. So like the things that colonize a leaf that's, you know, just emerged might be different than what's on an older leaf.
00:18:44
Speaker
And yeah, you do tend to find kind of these patterns where even though each plant and each leaf might have different microbes, when you kind of step back and look at the bigger patterns, you can see that there's probably more change happening over time than there is between individual plants that are sort of the same habitat, same subspecies and all that.
00:19:06
Speaker
That's amazing. So there's the leaves, they experience their own seasons too, all the microbes on them. How long do... plants live for they can be pretty long-lived so the estimates are usually like 40 to 100 years so there's probably some sagebrush shrubs you know in habitats that are just here around me in Boise Idaho that are 100 years or older they're pretty long-lived shrubs um and one of the cool things about them too is that they they have leaves on them all year round so even though they're not like um you know, it's not like a pine tree or something like that, right?
00:19:46
Speaker
But they still are sort of evergreen in the sense that they will have leaves on them even in winter. That's part of why they're so important for some animals as a food source during the winter when there's not a lot of other plant material around. Yeah, so it was neat that we could study them even in the winter and see what microbes were there.
00:20:05
Speaker
But they do shed their leaves periodically. So they like have some leaves that will remain on for around a year. And then some leaves that will just come out in the summer or early, so you know, late spring, early summer when it's, there's more water and sunlight and, you know, it's better conditions. From a microbes perspective, a hundred years could be millennia, right? Like how long is a microbe life cycle? Yeah.
00:20:30
Speaker
Yeah. You're going to have a lot of turnover of microbes over a hundred years. And do we know, i guess this is what you are looking at, what they contribute to leaf function or do they contribute to like, what is the what's happening with them?
00:20:48
Speaker
Yeah. We don't really know yet. I mean, we're just beginning to scratch the surface of it. um And so in a lot of other plants,
00:20:59
Speaker
People have found that microbes on leaves can definitely contribute to the functioning a plant and can help the plant survive different stresses or grow better. And our research so far, we have done some experiments where we try to grow seedlings with very few microbes, you know, as sterile as we can. And then we kind of can introduce different microbes. And we found that at least one particular bacterium that we know can live inside the leaves of the sagebrush as an endophyte.
00:21:29
Speaker
it can actually increase the amount of nitrogen there. And nitrogen is one of the most important nutrients for a plant to grow. so So that's a cool kind of hint that, you know, we can have some microbes living on the sagebrush that have these beneficial effects, but we're still just, I feel like starting to begin to learn what they might be doing.
00:21:50
Speaker
ah Yeah. And sagebrush is just one model system, right? Like the what they do with the sagebrush leaf could give insights into what they're doing on maple leaves or grass. Definitely, yeah. And I feel like we know we know a lot more about maybe like crop plants because people have been studying them for longer and are really interested in like, oh, how can you change the microbiome of a crop plant to help it do better in certain environments or conditions? But I think there's less known about
00:22:22
Speaker
our natural systems. The next system i wanted to speak to you about are the pitcher plants.
Carnivorous Pitcher Plants and Their Ecosystems
00:22:31
Speaker
Amazing, amazing plants. Can you can you tell us what a pitcher plant is, what it looks like, what what gets called and classified as a pitcher plant?
00:22:42
Speaker
Yeah, they're types of carnivorous plants. So they attract and eat, digest insects mainly to get essential nutrients that they need, like nitrogen and phosphorus that all plants need to grow. And pitcher plants in particular, they're called that because they have these modified leaves that look like little cups that hold water.
00:23:02
Speaker
And those little cups, they'll produce nectar around the edge of it. And the insides are very slippery So insects that come to eat the nectar, they'll often fall in and drown and they can't climb back out.
00:23:13
Speaker
But then even though pitcher plants are digesting those insects that drown inside of them, they also have these specialized insects that can live only in pitcher plants as aquatic larvae, and they depend on them as their habitats. Like they're only living if pitcher plants are there. They also have all these microbes that live inside of these little aquatic ecosystems that they contain.
00:23:35
Speaker
And another cool thing about pitcher plants is that they've evolved multiple times. So there's multiple groups of things called pitcher plants that are really not closely related. They're as related as like blueberries are to cacti. You know, they're in these very different groups of plants. And they've separately evolved a very similar shape, like a very similar form and a very similar function of attracting and trapping and digesting insects. We actually have them in in the Americas, in Southeast Asia, and this third group that only has one species in Australia.
00:24:09
Speaker
So I think it's really cool seeing how they've evolved this similar strategy for getting nutrients in like low nutrient environments to be able to survive, but in very different parts of the world.
00:24:22
Speaker
i was i was lucky in my in in my time to spend a lot of time in Canadian Ontario, it bogs with the Saracenia purpurea, the North American one, beautiful land.
00:24:37
Speaker
It's so fun. And bogs are just, it's so fun to spend time in a bog too. It's everything is so, everything is so different there. All of the adaptations to that environment and the sphagnum. Yeah. It's so fun to see them. It's again, like a a miniature, but bit alien world compared to other, other habitats.
00:24:57
Speaker
Yeah. You get these kinds of floating islands in bogs, which are so cool. And I just felt when I got to study, some pitcher plants and bogs, I felt so special to be able to go out there because it's a habitat that very few humans like get to experience because it's not an easy place to walk out into, right? They're very delicate habitats.
00:25:18
Speaker
And they, were talking a bit about this, they have a lot of rewards, right? The cranberries, the blueberries, why are there so many delicious berries? in box. They were worried getting there. Yeah, there were some wild blueberries. Yeah. Or maybe they're trying to drown you in the sphagnum and soak up your nutrients. Who knows?
00:25:36
Speaker
And then the Nepenthes, I was some also good timing. Yesterday I got to tour one of the greenhouses where I work and they had so many different Nepenthes species there all hanging. And it's not a plant I had really seen in person before, but of course it's one that you also work on. Can you talk a bit about Nepenthes and where it lives?
00:25:59
Speaker
Yeah, the nepenthes are the Southeast Asian pitcher plants, which are in a lot of different parts of Southeast Asia, even Northern Australia, like Northeastern kind of tropical part of Australia has some, and then they're found in Papua New Guinea and the Philippines and even over to India, Madagascar. um So I was able to study them in in Singapore and in Malaysian Borneo. It was so cool to be able to go into some of these amazing old growth rainforests in Borneo. Yeah, and I i just love them. They're really diverse. So the genus Nepenthes has
00:26:36
Speaker
over 100 different species in it. And they can be very different sizes from like very small little pitchers to very big pitchers. And they have all kinds of other interesting associations, like some that, you know, instead of eating insects, they're now getting their nitrogen from ah the feces of little animals, like some have bats that rest in them, and the bat guano gives them their nitrogen and others have these, they're kind of have a toilet shape, and they produce some food that these little tree shrews like to eat and then they poop into the pitcher plant. So there's there's such cool associations that they have. Yeah. And I was excited to be able to study both Nepenthes and Saracenia during my PhD to be able to, yeah, just just learn a bit more about these two very different groups, but that share also so much similarities. Yeah.
00:27:28
Speaker
And the Nepenthes, do they, are they epithetic? Like, do they grow on the trees? head Where do they grow? They're all hanging when I saw them. Yeah. Yeah, some are and some aren't. Yeah. So there's there's different different species have different things they do. And so some will actually, yeah, like wind like a vine up trees and you'll see the pitchers kind of going up a tree. Others are just in these little rosettes on the ground. So yeah, it depends on the species and Yeah, I was really interested in thinking about have when you have different species that are in the same habitat, so different, I was trying to find sites where different Nepenthes species were growing together in the same environment and thinking about how you might see microbiome differences among species, even though they're in that same habitat, the characteristics of that particular species does seem to select for like a particular microbiome, some differences in what bacteria and fungal yeasts and and other things are colonizing them.
00:28:30
Speaker
And the the carnivorous nature of both the Saracenia and the Nepenthes, so is it that the pitcher collects water or liquid and the insects drown and then the leaf absorbs it? What's the mechanism for getting the insect um nutrients?
00:28:56
Speaker
Yeah, they have they have these cups and and mostly what the liquid is probably rainwater, most of it. they you know they They catch rainwater when it rains and then they hold it in these little cups and they can still photosynthesize like regular plants can. And so they can get some of their nutrients just from CO2 and sunlight through photosynthesis. But for things like nitrogen and phosphorus,
00:29:19
Speaker
They get a lot of that from the insects they digest. And so in that fluid, there's a little bit of plant enzymes. They do excrete some of their own enzymes into that fluid, and it's different depending on the group. Nepenthes might excrete more fluid into that liquid um than Saracenia do, but they also have this whole microbiome in there. And so they eat, pitcher plants eat mainly ants. So if you look across different kinds of pitcher plants, the kind of primary thing they eat is ants, which, you know, makes sense. There's a lot of ants and Most ecosystems, some of the biggest Nepenthes that, you know, exist in in Borneo and other areas like that have even been found to digest small rodents. So people have found like mouse skeletons inside of them. But that's very, very rare. So I think people love to think about them as eating animals, but it's actually super rare.
00:30:15
Speaker
Even though some Saracenia in like, think it was up in Maine, they were finding that they were digesting salamanders, which I have also seen once before myself too, which, but that's very rare, right? Like it's not what they're normally eating.
00:30:29
Speaker
One thing that people ask me a lot is, well, if the environment in there is all like these enzymes, and you know, it's often ah acidic. And so they're like, what's going on with that? Why can they have live insects that still live in there? And mainly, it's things are only really being broken down once they die. So it's kind of like, once they die, they no longer have their own kind of immune systems, or you know, like their own systems of trying to keep out microbes and other things. And so that's when that's when they basically get broken down and digested. And then pitcher plants have these digestive glands on the insides of their pitchers where they can absorb nutrients back into the plant through those glands. And what what were the questions that you were interested as part of the research? What were you looking?
00:31:14
Speaker
What were the questions looking at the Saracenia and the Nepenthes? Yeah. So when I was comparing them, i was studying the Saracenia, a lot of them along the Gulf Coast and and up to Massachusetts.
00:31:27
Speaker
And then also the Nepenthes in Southeast Asia, so in Singapore and in Borneo. And I was really interested in how you have this convergent evolution of a host right, of a plant that has very similar form and function, but that's evolved separately. And then I was thinking, like, how will that shape the the microbes and the other organisms that are colonizing it? So if it's if it's creating this little ecosystem that has all these other organisms that are living inside of it, to what extent does that similarity of host extend to a similarity of the community inside of it?
00:32:04
Speaker
Yeah, there's lots of bacteria and fungal yeast and protozoa and rotifers and mites and midges and mosquitoes that live in pitcher plants on opposite sides of the world. And even though they might not be the exact same things, you do see that they tend to come from similar groups and probably are carrying out maybe similar functions.
00:32:23
Speaker
So you have this whole little ecosystem where you have some primary producers, some predators, some prey, some things that are competing, some things that are helping each other out. And on the scale of individual species, you might see differences. Obviously, on the opposite sides of the earth, there's going to be different things. But then seeing that they come from similar groups and can kind of fill these similar ecological roles, I thought was really fascinating.
00:32:50
Speaker
it's so interesting in thinking how different the ecosystems that they live in have evolved in, but that within the picture, there's similarities. And you use, you know, you use the word microcosm in your research too. What does microcosm mean in the context of the the picture plants that you're looking at?
Microcosms in Pitcher Plants
00:33:12
Speaker
It's like a little ecosystem. So it's like, you know, a small scale thing that still has some elements, some like reflection of like a larger scale ecosystem as well. And so that's how I think about it is like these, part of the reason I think pitcher plants are so cool is not that they're these super weird things, you know, that are really kind of unusual and out there.
00:33:34
Speaker
i think that it is a nice way of being able to study a little ecosystem that's manageable where you can actually see everything that's there and kind of try and understand what they're doing and how they're interacting without having to think about a whole rainforest or a whole lake where it might be totally untractable to be able to actually look at the interactions of all the things, you know, that are in this big lake.
00:33:59
Speaker
Yeah. And those interactions are the the same, right? It's like competition between organisms, predation, mutualism, and the pictures, the wildest,
00:34:10
Speaker
I guess the liquid communities the pictures are kind of like miniature pawns and guts at the same time. Is that accurate? You know, they're not going to be exactly like any other ecosystem because they are their own thing. But I think they have these characteristics that we can then use on the bigger scale, thinking about kind of fundamentals that apply to other systems. So thinking about the decomposition and the breakdown of ah food that's happening that might be more like a gut system. um And the fact that it has is a host association, right? It's like a host microbiome association. And that's kind of more like a gut. But then they are these little watery pools. So then in that way, they are kind of more like a lake, but on a very, a very very small scale.
00:34:58
Speaker
And for this, just to visualize this research, so you were collecting little vials of the liquid from different pitchers within one plant.
00:35:08
Speaker
different species within the same community. is that how you sampled it? Yeah, yeah, I was, because um a lot of my sampling was done in kind of places that were far away from easy access to like refrigerators or freezers or labs or things like that. I was collecting things and then I would add preservatives, like I wouldn't be able to take things live back to the US from Borneo, for example. So so i would collect things as sterile as I could, you know, using sterile large pipettes and then into these sterile tubes that I had brought with me out into the jungle or wherever I was sampling out into the bog or the pine, pine leaf savanna.
00:35:49
Speaker
and And then i would would take them back and sometimes I was in a hut or in a motel or like wherever I was able to bring those samples back to. And then I would test things like I would you know record the volume of what I had collected and I would look at the acidity and other characteristics of it. And then I would add a preservative to be able to to keep that and then bring it back to the lab to be able to look at the DNA. of all those different organisms and understand more about who is there and what they might be doing.
00:36:21
Speaker
Yeah. Yeah, I love those, the less glamorous side of fieldwork, the processing everything in your cabin, motel, wherever, as much time goes into that, right? Yeah. Yeah. And sometimes I wonder what the people...
00:36:38
Speaker
who would clean the the trash afterwards, but they would be like, why are there all these pipettes and little pH strips and things like that? Yeah, you're like, don't throw up my weird juice.
00:36:53
Speaker
Going back to just what you you mentioned before, the communities were more were more similar. i guess it was a surprise that they were similar worlds away. Yeah. You mean the ones across Saracenia and Nepenthes?
00:37:08
Speaker
Yeah. Yeah. That was a surprise, I think, um because it is the opposite sides of the world and they are, they can be in pretty different habitats. Some might be in, in, you know, more like jungle. Some might be more in like a bog. Right. But the fact that the pitcher plant is creating this little,
00:37:30
Speaker
type of habitat that kind of has, you know, insects coming into it. It is kind of this similar shape. It has this similar function. um It does seem to select for similar organisms, even on opposite sides of the world. And i I thought that was really cool. You know, that pitcher plants, the microbes living in pitcher plants were more similar to each other, even though one was in Massachusetts and one was in Borneo, than they might be to just like soil or bog water or something like that. That's right the environment around them. So I thought that was really fascinating, like that sort of the type of habitat kind of selects for a particular type of community. And i I think that's really cool. For me, it gave me a lot of insight into how microbial communities form and the ways that you might find similar types of microbial communities, even in very different places.
00:38:25
Speaker
So interesting. And how do they, do the microbes find their way to the pictures? Like, I'm just thinking about deaths, and there's some like transfer of the microbiome between a mother and a child, but like, how do they develop?
00:38:41
Speaker
It's a good question. I think we're still figuring out, but they they definitely are kind of a subset of what might be in their environment around them. so So part of the reason that the community is different is just because it is kind of a subset of a much larger set of kind of source pool, right? Of what could be out there. So so soil and even like bog water are gonna have a lot more different microbes than might be found in a pitcher plant. A pitcher plant is a little bit more kind of selective of an environment, maybe more like a gut is a little more selective of an environment than, then you know, soil, right? Which can have tons and tons of different microbes in it. um And so, yeah, so I think they get there partly just through through And then probably partly from insects that are that are moving between the different pitchers, both as prey, but also as the ones that live inside the pitchers, which we call inquilines, because they like live inside those little ecosystems. So so they're probably coming in through the air, through the rainwater, from their surroundings. They might come
00:39:47
Speaker
you know, from splashes of other pitcher plants, or they might they might come also on insects that have visited other plants as well. but But a lot of them are probably coming just from that surrounding environment. And then the ones that really thrive and do well are the ones that can really take advantage of that particular habitat.
00:40:07
Speaker
And when we when we're talking about selected, we mean if it can't survive, it dies. Yes, exactly. Yeah. So the ones that can survive are the ones that you're. Yeah. That's what I mean we call it like environmental selection, right? Where the environment has to be appropriate. It has to have the right food, the right acidity, the right conditions, the right amount of oxygen, right? All these things have to be right for it to be able to survive and reproduce and make more and more cells.
00:40:37
Speaker
i just want to, talk about one last term for the the pictures i guess when we talk about convergent evolution the saracenia and the nepenthes have evolved you know similar structures to do similar things not having not being very closely related at all to each other you also have discovered convergent interactions what does what does that mean but yeah convergent interactions it's a term that
00:41:08
Speaker
I coined during my PhD. So it was something I thought a lot about during that time. And for me, it really refers to interactions that establish independently between different organisms, but they share really similar functions or characteristics. So i think you can see these cool patterns of convergent interactions happening all over the world. And one that I really love that's close to my heart are ant plants, where you find that ants and plants, um interact and often the ants will protect the plants from herbivores, things that are trying to eat it. Sometimes it's insects, sometimes it's as big as a like giraffe or an elephant. So they'll protect those plants very strongly, you know, they're good protectors. And then the plants will evolve to produce housing and food for the ants. And you find these relationships between ants and plants that have happened independently in South America, in Africa, and in Asia. Like you see repeated
00:42:09
Speaker
examples of these close interactions between ants and plants that have very similar characteristics, but have evolved totally independently. And, and the pitcher plants, I think have that a bit too, right? Where you see that they probably have these similar functional roles of the microbes that are there are helping to break down the insects and, and get those nutrients released that so that the plant also can absorb some of them. And they have these same kind of interactions with similar microbiomes in different parts of the world, and they've established them independently. So I think it, I like this idea, because I think it speaks to how associating with another species can be a really good strategy for survival. If there's something that might be hard to evolve to do yourself, maybe instead, you can also ah like evolve an interaction with another species that can help to do that thing. So it kind of allows you to get over maybe some evolutionary hurdles by instead creating this interaction, this tight long-term interaction.
00:43:10
Speaker
think that's so interesting and just speaks to the complexity, right? Like the ant plant interactions we can we can see, so we can characterize them, but all of the interactions we don't see, no species is in isolation, right? Like it all has all of its relationships with everything that it might encounter or pollinate it or eat it or whatever.
00:43:38
Speaker
and it's just never endingly complex. It's really hard to characterize, isn't it? Interactions all the way down. Yeah. I was speaking with someone recently about um, belt. Have you heard of um belt? Um wild.
00:43:55
Speaker
It's like a German term, right? Yeah. It's a German term, but meant to describe it's talking about animals. that meant to describe like the experience of an animal within its environment, just as a way to like stretch your brain to imagine like you know like an octopus knows the ocean floor very differently than you would, and it knows what shells are a good habitat. The different sensory, the different way it uses, experiences, utilizes its world, what menaces it all of that. and
00:44:29
Speaker
It's just interesting to think about plants, too, to to apply that to plants. Like, what is everything from a plant's perspective that it is seeing and interacting with? And it goes from the, you know, the macro scale of squirrels, whatever, eating it, living in it, to the to the micro. And when we when we spoke last, something I was really thinking about, too, was i think I was marveling at how amazing it was that how there could be so much diversity on a leaf and that that is such a small micro habitat and then you pointed out that it's actually you know what's the surface area of leaves in one forest or in one town or in one place that it's actually a massive it's actually a massive habitat could be one of the biggest habitats on the leaf and it was so interesting thinking about that that scale and with that miniature world sometimes
00:45:25
Speaker
this small is actually so large we just can't really access it or or see it and all of the complexities that we're really just beginning to understand on one plant it's it's really humbling guess and in your opinion like what has kind of thinking about and studying microbes given you has it kind of changed your perspective what can we kind of learn from considering them and their world a bit more Yeah, i think that's a great question. Yeah, and you were mentioning sort of the the size of surface area of plants. um It's estimated that it's it's about twice the surface of the whole earth, the above ground parts of plants in terms of the area. And so I think that is so cool, right? Where you think about that is just such a vast habitat, even though you might think, oh, microbes on a leaf, like that sort of niche. But actually it's this like huge microbial habitat, right?
00:46:24
Speaker
I find that studying microbes really connects me with with wonder of the world, how you can have this vast diversity That's ancient and unseen and tiny, but then it all adds up to have these really big effects, how you can have these really big positives and these really big negatives, right? And it can teach us that the combined action of many small things can add up in a huge way. And as you were saying, there's all these interactions, right? We're never really doing anything alone. We're actually these whole ecosystems ourselves. Everything is interconnected. We rely on each other. You know, without microbes, plants wouldn't exist and we wouldn't exist. And plants really form the basis of our whole food system, our existence on earth. And so I think just thinking about how these very small things really add up to have these huge
00:47:16
Speaker
actions and effects is something that that i I like to think about. And it it does really make me feel that everything is interconnected. Expanding to to think about, isn't it? And they can create weather, as you said. The cyanobacteria gave us oxygen, paving the way for everything else. And we don't really give them their due credit, do we?
00:47:42
Speaker
The complexity of relationships and interactions between organisms in your work is also really interesting. can you reflect on that complexity?
00:47:53
Speaker
yeah yeah. I think we often try to put things into these categories as being good or bad. And we do that a lot with microbes too, right? Like this is this one causes disease or this one's a beneficial microbe. but But I think that can often be way too simplistic. Sometimes there are good effects and some bad effects in the same interactions. You might have some competition, some mutualism, you know, some disease, but also a benefit as well. And these interactions can also change their form over time and depending on context. So in like one particular environment, something might be helpful. But then if the environment changes, it might no longer be helpful and it could actually be harmful. So that's one thing that I think is is really interesting and important to remember is just that we need to look beyond these easy kind of black and white categorizations
Implications for Conservation and Restoration
00:48:44
Speaker
of things and and maybe think more about interactions as being changeable and evolving and also really context dependent.
00:48:52
Speaker
Like are there kind of applications or benefits from a conservation perspective to understanding plant-microbe interactions? what what can we kind of How can we use this knowledge?
00:49:06
Speaker
Yeah, I think that's a really new and growing field of thinking about how we can use microbes for conservation or restoration. And and we're starting to think about it with sagebrush in in my research group a bit. There have been a few instances, there was a cool example in Hawaii, where there was a plant that had gone locally extinct, but then inoculating them with particular microbes helped them to survive and reestablish a little bit. So we know that microbes can help plants deal with stresses like drought or too much salt or a lot of these things, higher heat, like things that are happening in in our world right now. And beyond plants, we also know that they can help animals, like in the case of frogs, they might help them, you know, skin microbes might help them deal with other microbial diseases like chytrids that are killing some of the species off. So I think there's this growing field of of trying to think about how we can use inoculations of of particular microbes or of particular microbiomes to help conserve and restore many different kinds of species. And when you're thinking about it from the whole ecosystem perspective, you know, after a fire or after a really big disturbance, you're going to have different microbes there, right? And that might really affect what else can grow. So being able to think about the microbes as this integral part of it, I think is, i hope, I'm hopeful that it will help us to improve some of our restoration outcomes.
00:50:47
Speaker
That was my conversation with Dr. Leonora Biddleston. Thank you for listening and thank you to Leonora for sharing her work. Plant Kingdom is hosted and produced by me, Catherine Paltz, and our music is by Carl Deiter.
00:51:00
Speaker
Listen to us wherever you get your podcasts and check out our website at plantkingdom.earth.
00:51:34
Speaker
you