Science Friday - Global Heat Wave, Indigenous Peoples Genetic History, Heat-Adaptive Plants. July 22, 2022, Part 1

Episode Date: July 22, 2022

Earth Faces A Global Heat Wave Temperatures are higher than normal for much of the planet this week—and while the heat wave in Europe has had much of the attention, over 100 million Americans in 28 states were under extreme heat advisories this week. Yasmin Tayag, a freelance science editor and writer based in New York, joins Ira to talk about the global heat wave and other stories from the week in science—including the president’s COVID diagnosis, an uptick in drug-resistant infections, and the question of whether previously uninfected people are “sitting ducks” when it comes to new COVID variants. They’ll also tackle some lighter topics, including new studies of how an elephant’s trunk works, and the genetics of how penguins came to prefer colder climates. Genetics Suggest Indigenous People Arrived In Americas Earlier Than Some Thought For years, grade school textbooks have told the story of how the Americas were populated by people crossing a land bridge from Asia and migrating in the safe havens between glaciers. In this version of history, its inhabitants arrived 13,000 years ago. But that story needs an update, thanks to both new archaeological evidence, and the increasingly robust tools of genetic analysis—ancient genomes extracted from millennia-old human remains suggest a much longer history of people in the Americas, perhaps by thousands more years, and aligns with the oral histories of Native Americans and other Indigenous peoples. The genetic evidence also brings up new mysteries, including evidence of some groups of ancient peoples with no direct descendants today. Producer Christie Taylor talks to University of Kansas anthropological geneticist Jennifer Raff, the author of Origin: A Genetic History of the Americas, about the growing evidence for the need to revise the history of the First Peoples. Plus, why researchers seeking to tell that story need to work directly with contemporary tribes to ensure that exploitative scientific practices of the past are not repeated. Can Genetic Modification Help Plants Survive Climate Change? Temperatures around the world are reaching all-time highs as major heat waves cause extreme weather and climate events. Earlier this year, temperatures in India and Pakistan soared to 120 degrees Fahrenheit, followed by months of unrelenting, unseasonably hot weather. A brutal heat wave is now moving across Europe, fueling devastating wildfires, and producing Britain’s highest temperature on record. Propelled by climate change, future heat waves promise to increase in frequency and intensity, posing a dangerous threat to human health. But people aren’t the only ones at risk. Many plants—including essential food crops—struggle to survive as temperatures rise. When conditions heat up, a plant’s immune system can shut down, eliminating its defense mechanism. With key agricultural regions already experiencing record highs, global food supplies face potentially devastating consequences. Ira talks to Sheng-Yang He about his research published in Nature last month that offers a potential solution—using gene editing to strengthen a plant’s defenses against increased temperatures. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

This is Science Friday. I'm Iroflato. A bit later in the hour, we'll talk about how high temperatures weaken the immune system of plants and what genetics is telling us about when the first peoples arrived in the Americas. But first, unless you happen to be listening to this in Australia, you're probably a little bit warmer than usual right now, right? Temperatures are higher than normal for much of the planet, and while the heat wave in Europe has garnered much attention, over 100 million Americans were under extreme heat advisories this week. Joining me now to talk about that and other selected subjects in science is Jasmine Tyag. She's a freelance science editor and writer based in New York.

Welcome back to Science Friday. Thank you, Ira. It's good to be back. Let's talk about this heat. Just how hot is it? Oh, it's hot. It's hot. Not in a good way.

Is there anywhere that's colder than usual, I guess, is what I'm looking for? Well, in Australia, it's winter, and they're experiencing some record cold. Really? Yeah. In Melbourne, they have experienced near freezing temperatures. And that's unusual for them? They don't usually have that? Not this cold. It's been unusual for them. And I think it's all part of this pattern of extreme weather everywhere. And, you know, this is not just the weather story, right? It's a story about health and infrastructure because they're all being impacted by the weather. Absolutely. You know, the health impacts of the heat especially have been really terrible,

especially in Europe where, you know, societies are just not really built for this kind of heat. You know, in the UK, those houses are built to retain here, not to let it out. And the health issues are really being seen here at home, especially for people who don't have access to air conditioning, you know, even refrigeration in some cases. this kind of heat can be deadly. And last week, some legislation aimed at targeting climate issues was torpedoed in the Senate, in the U.S. Senate. But what is Europe doing? Well, Europe has a European Green Deal where they're aiming to be climate neutral by 2050. And recently, they launched an additional effort to cut emissions by 55% by 2030, which is a huge goal.

and that is very soon. But being put to the test right now, because with all of this heat, the demand for energy is much higher. And at the same time, there are sanctions on importing Russian energy. And the question now is, will Europe make the choice to double down on clean energy

or will it just look to get gas and oil from elsewhere? Yeah, because they have been world leaders in Europe, in making the commitment to go green? Yeah, you know, I really hope that they take this opportunity to make the right choice, and I hope that will set an example for the rest of the world. Now, let's move on to some other issues, and one in particular is that COVID is not going away, no matter whether we want to wish it to do that. And this week, even President Biden has tested positive for the virus with mild similar.

and thank goodness, but there's a story about another impact of the pandemic in other drug-resistant infections. Tell us about that. Yeah, the CDC reported this week that during the pandemic, there was a huge spike in drug-resistant infections. And that, they think, was caused by the use of drugs like antibiotics early in the pandemic to treat patients. You know, doctors and nurses at that time didn't really know what they were dealing with. And so they reached for these drugs, which ended up not working. But what they did do was increase the chances for resistance because these patients were in hospitals for so long, you know, days, weeks at a time where they were being exposed to all these common hospital bugs. And that's one of the reasons why infections seem to

spike. Because they were in the hospital so long and exposed to these, that makes sense. So in this case, maybe the problem was too much care or health care applied in the wrong way. Yeah, I would say it's closer to the latter, but I, you know, I really don't want to blame doctors and nurses. They were just trying to do their jobs. And, you know, March 2020, nobody knew what was going on. We were just in a panic. And with all the new variants, including some that appeared to be more, you know, transmissible. We are seeing upticks in the infection numbers, and you have a piece out this week in the Atlantic asking whether people who haven't been infected yet are more at risk. Yeah. The question that I post to myself is, are people who haven't had COVID yet sitting ducks? And I think of these

people as COVID virgins. My fiancé is one, so it was a very personal issue. And it's personal to me because I'm one of those also. I wanted to hear the answer. Well, hopefully this will be somewhat encouraging news. The data suggests that people who haven't COVID yet are quite vulnerable right now because so many of the infections happening right now are first infections. However, None of the experts I spoke to would say outright that people who are COVID virgins are more at risk. And that's because everyone right now is at risk. There are a lot of reinfections happening now, which suggests that natural immunity isn't holding up against these new variants. As a result, people who have had COVID before may not actually be more protected than people who have never had COVID.

So the guidance that experts gave applies to everybody. And it's the same stuff we've always known. Get vaccinated, get boosted, get your second booster if you can. I think Biden just had his, which I think is setting a good example for everyone, especially people in his age group. And if you're vulnerable or elderly avoid crowded environments and wear a mask. You know, as one of these virgins that you talk about, I'm almost tempted to say, hey, let me get the virus now while my immunity is up because I'm double-boasted and I'm still in the middle of my high boost period because if I wait till October when maybe my booster runs out and then get infected, it will be worse for me then if there's not the third booster around.

It's tempting, right? It's tempting to be fatalistic. right now, especially because we're all just so tired and fed up with all of these behaviors that we're told to do. But there are still so many good reasons to try to not get COVID. Chief of them is that I think people forget how bad illness can be even if you are vaccinated and boosted. You know, sure, you're not going to end up in the hospital, but it can still put you out for a couple of days. And I think the other major thing people need to be thinking about is the specter of long COVID.

It's still so poorly understood and it can get anyone, even if you have a mild or asymptomatic infection. And lastly, again, we don't know how protective natural immunity is against these new variants. So even if you get sick now, you might still get reinfected later this year. Yeah. That's what's keeping my vigilance up, all those reasons. Let's move on to something a bit lighter. A story about elephant trunks.

How can you get lighter than this? Elephant trunks and how they move? Yeah, it's a delightful study, and I'm so happy that someone out there is studying this. So you think of elephant trunks as just this long, muscular thing that can pick up branches and leaves. But what the scientists found is that it's not just muscle, that helps it do what it does, but also its skin. And so this might be surprising because you think of

elephant's skin is just, you know, wrinkly and uniform. But in reality, it's not. The skin on an elephant's trunk depends on where it is. The skin on the top of the trunk, for example, is different and more flexible than the skin on the bottom. And this all feeds into a greater understanding of how the trunk itself moves. So instead of stretching uniformly like a tongue, the trunk moves more like a telescope. So the tip will always move first in order to reach something followed by the adjacent segment. And the last part to move is the part closest to the face. The scientist hypothesized that this happens because elephants are lazy and the part closest to the face has a lot of muscle. So moving, it takes a ton of effort. And so in order to reach something, they would much rather use the tip of

their trunk, which has fewer muscles and is a lot easier to move. I get it. If I were the size of an elephant, probably I do that also. Finally, genetic research and how penguins became able to live in the cold. I love penguins, and I want to hear the answer. How did they adapt to the cold? Yeah, I mean, the genetic analysis pinpointed these genes that are responsible for some very key features for living in extreme cold. But I want to back up and mention what I found to be the most interesting part of this research, which is that penguins were not always cold adapted. They used to live around the equator, which was news to me. I can't even imagine seeing a warm weather penguin. When they lost their ability to fly about 60 million years ago, they just kind of became land animals and fossils have been found all along the equator.

And over time, they gained all these new mutations that allowed them to adapt to cold climates. So some interesting ones were genes that control the amount of fat that they can store or genes that helped turn their. non-functional little wings into flippers that were way more functional for the water. The one I found most interesting was the fact that their taste buds are, they can only taste salty and sour, which the scientists say is really helpful if all you eat is fish. You know, with climate change and the melting of all the ice in Antarctica, you hope that the penguins are going to make it, just like you worry about the polar bears in the North Pole. Yeah, you know, I think what the study really shows is that penguins have shown an amazing ability to evolve and adapt.

And what they really need is time, just like all the animals just need time to evolve and they will. What I hope that we can do is give them that time. Yeah, let's hope that the time is on their side. Thank you, Yasmin. Thank you, Ira. Yasmin Tayag, freelance science editor and writer based in New York. We're going to take a break, and when we come back, how genetics are filling in gaps in the story of when people first came to the Americas, and why that arrival keeps looking earlier and earlier. Stay with us. This is Science Friday. I'm Ira Plato. When you were in elementary school learning about the peopling of the Americas, I'll bet you heard a story that goes something like this.

13,000 years ago, glaciers from the last ice age were just starting to melt across North America. And a group of people from what is now Asia crossed into North America by a land bridge through what is now the Bering Sea, and they found the path through the ice to North America. Anthropologists called them the Clovis people, and we know they were here because they left very distinct spear tips all over the continent. And for a long time, we assumed they were the first people to arrive. And then— Hey, hi, Ira. Hey, wait, wait a second. Oh, hi, Cy-Frize Christy Taylor.

Am I telling it wrong? Well, so unfortunately, the real picture is actually pretty complicated and involves some disagreements among scientists. But what many archaeologists are starting to think is actually that the first peoples, the ancestors of indigenous people in the Americas, were here much earlier than previously thought. And I'm talking thousands of years before that 13,000 number you just threw out. Also, they think the Clovis people weren't the first people here. Really? Where is all this new evidence coming from? Well, some of it is from older archaeological sites that have been found recently with evidence of human habitation, but a lot of it is also genetics. We're getting better and better tools for sequencing DNA and extracting very old DNA from people's remains.

Wow, this is much more interesting than what I was talking about. Fell us in on the rest of this story. Yeah, I talked to Dr. Jennifer Raff. She's an anthropological geneticist at the University of Kansas and Lawrence. And she's the author of the book Origin, a genetic history of the Americas, which came out earlier this year. We started by talking about how the timeline of human arrival is changing thanks to the introduction of DNA evidence. In the genetic record, we can see that there were splits between populations of ancestral Native Americans that coincide with or date to just after the beginning of the melting of the ice sheet that once covered most. of Northern North America. So these splits take place after 17,000 years ago. These branches diverge very, very rapidly,

which is a signal of rapid population movement across a landscape that's likely devoid of other people. And so the genetic record shows that occurring much earlier than the Clovis peoples. In addition to that, the archaeological record shows candidates for early archaeological sites that date between 14 and 16,000 years ago. What these approaches are telling us is a really fascinating story of a population that emerged from two previous populations, one in East Asia and one in northern Siberia. There's a lot of blanks we still have to fill in, but these two populations encountered one another during the peak of the last glacial maximum or just before.

And this climate event really peaked between about 26 and 20,000 years ago. And so we see evidence for gene flow between these two populations somewhere. We don't know where exactly they encountered each other. And then they become isolated for a period of a few thousand years. And this period of isolation is when they evolve genetic variants that are unique to the peoples of the Americas. And there are so many aspects to that story that I've just told you that we really can't answer yet. I mean, overall, what can genes tell us that the archaeological sites themselves, you know, bones, settlements, spiritips? What can genes tell us that those can't?

So what genetics tells us is biological history. Looking at genomes of individuals can tell us how closely they're related, how closely they're related to past. populations and two global populations. And we can also look at genetic evidence and use it based on population genetics. We can estimate things like population size changes in the past. We can estimate the dates at which two populations last shared a common ancestor. We can look at how natural selection has affected populations and other forces of evolution, genetic drift and mutation and gene flow. And so from all of these data, we can build models about the past and use those models as a test of archaeological data. So I think that really the most powerful approach is to integrate archaeology and genetics as best as one can and try to come up with the most comprehensive story of history that we can that matches both datasets.

It's not easy at all. It really is not. It sounds like it. Well, and you don't even have just one data set, because you're talking about both ancient remains of people who died thousands of years ago and the DNA from their descendants, you know, indigenous people in the Americas today, right? How do those two sets of genealogies complement each other as well? Well, it can be really tricky because, of course, we want to avoid defining who is Native American in genetic terms, right? And present-day indigenous people, peoples of the Americas are genetically variable. They have ancestry from many different populations. A lot of this ancestry comes from European contact and colonization processes that took place after 1492. So it can complicate trying to reconstruct histories of the deep past, the very, very ancient histories. A lot of times to look at the stories of those ancestors, one has to look mostly at ancient

DNA. And right now, we have a very limited sampling of genomes across the Americas from these ancient ancestors. And there are a lot of reasons why that's the case. It's a lot of ethics, a lot of history that geneticists really need to take into account and be sensitive to when we're doing our work. Let's visit your lab virtually. You have received a new genome. What do you do with it? What happens? The process of our research always starts with the tribe or the the descendant community and talking to them about what questions they have, what would they be interested in looking at, and bringing to them the questions that we might be interested in, and coming to an agreement before we even bring any ancestral remains into the lab,

that we always get that worked out first. What can we do? And how should we handle these remains? And we bring that sample into our isolation facility at the University of Kansas. And that facility has a positive pressure and all the other attributes of an ancient DNA lab. So everything is covered in bleach. Everything is. We are very, very careful about what we bring into the lab and how we work in it to preserve as much as possible a DNA-free environment, or at least an environment free of contemporary human DNA.

And that sample is then bleached and the surface of it, if its bone or tooth, is removed. And the process of DNA extraction begins, which, is a long and complicated and multi-day process and takes a lot of patience on the part of the worker to do this in a way that does not contaminate it with their own DNA. You're extracting the DNA, you're sequencing it. What are the things you're looking for in the sequence? So it, again, really depends on what kinds of questions that we have agreed to with the community that we're working with. We are in our lab group also very interested in the very earliest peopling of the Americas. And so if the community finds it appropriate, then we will look for, or how does the genome that we're working with here fit with existing models of the population history of these earliest peoples? We're also interested in really small-scale relationships between individuals buried in the same cemetery,

relationships between different groups who may have been trading partners and was their gene flow accompanying that trading relationship. Can we see the effects of European contact in these populations? Do we see evidence for gene flow from European populations or other populations, or can we see the impact of European contact on population size changes in these groups? We are really interested in everything that one can learn from genetic relationships. I want to go back to some of the ethical questions that you talk about in this book, Origin. We're not talking about a story of people in a vacuum, but one that involves people who are still alive. today and people who have been exploited both in the process of colonization and by scientists who are looking for exactly the story you're trying to tell. You know, it was really important to me as

I wrote this book that I not only explained what we think we know today, but how we came to those scientific understandings. And this history of our discipline, and it's not just genetics, it's archaeology, it's anthropology, it's, you know, scientific study in general. this history is deeply rooted in colonialism and centuries of exploitation of indigenous peoples. And it's really important that the process of consultation is a process of obtaining permission. It's also a process of making sure the community is aware of all the implications that work can have for them. And soliciting from them the parameters for how to do research. So in the past, many scientists have not understood, I think that many non-Native scientists have not understood that these ancestral remains are sacred. They're people. And doing work in the way that we do it, it can damage the remains. It can actually go against the ways in which some tribes view the dead. And so to do this work respectfully, it's absolutely necessary that way.

one talks to present-day communities about the ways in which one can handle these ancestral remains and what is okay to do and what is not okay to do. And throughout the history of our field, unfortunately, that sensitivity has not been there. This field has really changed in the last, I would say, decade, really, really changed. And that's in large part, thanks to the leadership of indigenous peoples who have really educated non-native scientists on these issues, but we still have a long way to go, I think. And I am hoping that by bringing this discussion to the public, it will be a little bit more accessible and a little bit, people will understand a little bit more the issues involved. Well, and I guess a follow-up to that, and that is just

why is it important for scientists to establish this story of people arriving in the Americas? You know, how and when humans first made their homes here? Would it materially change the life? of those people's descendants? That's a really good question, and it's one that I think about a lot. There are a couple of different ways to answer it. One way is to say that to understand the genetic history of humans globally is to help inform our understanding of the processes which have shaped genetic variation in present-day communities.

And understanding that evolutionary history can have real importance for medical research. And again, with caution and with care, because indigenous peoples have had, as other marginalized people, a very long history of exploitive medical research as well. So that's one answer to your question. But another one is there is a lot of bad information out there about history. Quite often, this alternative history is extremely racist or at least is used for racist purposes. to deny the sovereignty of indigenous peoples by saying, well, they weren't the first people in the Americas, or it was really Europeans, or, you know, ancient people from other parts of the world. So genetics can show us, for example, that the first peoples of the Americas are the direct ancestors of present-day indigenous peoples. I mean, that's, you know, one fundamental thing.

But it can also, in concert with archaeology, show us that these first peoples got here very early, much, much earlier than I think most people realize, most non-Natos. Let me correct myself, because indigenous peoples will be like, yes, we know our ancestors have been here a long time. But it is actually a shame that we have to confirm this with genetic data for some people to believe it. But it's really fascinating. And what's, been interesting to me is in looking at these new stories that that are emerging from genetics is how these origins are getting pushed back earlier and earlier. And so, you know, very early in the history of archaeology, there was an argument about whether the first peoples were even ancestors to Native Americans. But, and then it was, well, they've only been here 5,000 years. And then it was, well, they've only been here 13,000 years. And now we're saying before 15,000 years. And even And adding to that now, there's a site that was just published in New Mexico, the White Sands site, that shows evidence of human footprints potentially dating as early as 21 to 23,000 years

ago, which means, yeah. And so we have to now look at that evidence and say, okay, and I will say, there are a lot of archaeologists who disagree with the dating methods used. But if those dating methods hold up, you know, what does that mean for our field? how do we incorporate that into our models? How does that intersect with genetics right now? And how can we reconcile all these different data sets? And so I think that this study,

as long as it's done carefully and with sensitivity to indigenous people's perspectives and respect for their own histories, transmitted orally for generations and generations, if we can do this work respectfully and in a good way, I think it can benefit indigenous communities, if only to push back on some of these narratives. And then again, though, they shouldn't need

scientific confirmation of this, right? But there it is. Just a quick reminder, this is Science Friday from WNYC Studios. Talking to Jennifer Raff, author of the book, Origin, a genetic history of the Americas. Your book is called Origin, which refers to the beginning of a people, of a history.

Do you think we'll ever know the entire story? No, I don't think we'll ever know the whole story. I really don't. I mean, I am optimistic that we will get closer and closer. But by far, the majority of archaeologists and geneticists, including myself, interpret the evidence as showing people present in the Americas by at least 16,000, 17,000 years ago, or perhaps if White Sands holds up, if the dates hold up, maybe there were people here even as early as 25,000 years ago. How we reconcile those dates is going to be a fashion. conversation over the next few years. And I hope that my book kind of provides a framework for people to understand where that conversation is going and what it implies. So we should all be setting Google alerts for White Sands. Yes, I think so. It's one of the most exciting sites that has been published recently, I think. Jennifer, thank you so much for joining me today. Thank you so much. Jennifer Raff is an anthropological geneticist at the University of Kansas in Lawrence and the author of the book Origin, a genetic history of the Americas.

I'm Christy Taylor. Thank you, Christy. And if you want to hear more about the revolutions and genetics driving our understanding of history, you can read an excerpt of Jennifer's book, Origin, on our website, sciencefriiday.com slash origin. Once again, sciencefriady.com slash origin. And if you need more summer reading suggestions, I suggest this pick from SciFri Book Club listener, Ophelia.

I'm reading the Code Breaker by Walter Isaacson. Absolutely fascinating and a must read for anyone interested in RNA and how bacteria taught us how to fight viruses. You can join the SciFri Book Club for more recommendations from readers like you. Find out what we're reading next and join our online community space all at ScienceFriday.com slash book club. After the break, it's hot out there and getting hotter, and that's bad for a plant's immune system. But help may be on the way. Stay with us. This is Science Friday. I'm Irafledo. In India and Pakistan, temperatures topped 120 degrees Fahrenheit earlier this spring, and then stayed above 100 degrees for three consecutive months. Of course, you know that Europe is currently sizzling under similar temperatures, record-breaking in many countries.

And as climate change continues, we're only going to see more heat waves like these, which is dangerous for human health, sure, but another concerning effect of deadly heat, plants, including food crops we depend on, have weaker immune systems when it's hotter, which means more diseases wiping out harvests. Worrysome on a warming planet, yes, but researchers are working on solutions. Research published in Nature last month offers one option, a gene editing solution to keep crops healthy even at high temperatures. With me is Dr. Senyung He, a professor of biology at Duke University,

and investigator at Howard Hughes Medical Institute, and an author of this new research. Welcome to Science Friday, Dr. He. Thank you very much for having me on the show. You're welcome. Can you give us some plant immune systems 101 first? Sure. Lent actually have a very powerful immune system.

It's actually similar to a means. major branch of immune system that humans and some other animals have, it's called innate immunity. What it is is that plants have these immune receptors that can recognize all sorts of pathogens and insects, actually. And once that recognition occurs, plants will produce defense hormones, including a hormone that in this study, we focused on quite bad cellic acid. And so these hormone basically amplifies other cellular immune receptors.

to make plants resistant to pathogens and insect. Yeah, so plants don't have the antibody system that we have, but still plants have, you know, exist on Earth for hundreds of millions of years, so much longer than humans, many animals. So I think the plant immune

system is very powerful against diseases. That immune response sounded a lot like aspirin. Yeah, yeah. Cylacic acid is actually a very close-related compound. Aspirin, in fact, aspirin was invented based on the salicycic acid.

You know, old days, humans chew the will of bark that contain a lot of salicylic acid. That's where the aspirin was initially discovered. And so we take aspirin, yeah, for a lot of human condition. But plants actually make their own medicine. So when it gets hotter, do they produce more of this? Or did they not and just wilt or get sick? So actually, it turns out when it's hot, the plants are used to the cool weather condition, like Europe, you know, part of Asia or North America, it's a lot of vegetables or all you see, they actually don't like hot temperature either. So they produce less cellic acid.

And because of that, the whole plant immune system is kind of suppressed. And so they are more prone to pathogens and insect attacks. So are there any particular kinds of diseases that might be most damaging? Yeah, so cellic acidic control plant immune response to a large group of pathogens we call biotrophic. These pathogens like living cell. Some insects also like living cell. So cellic acid is really important for plant defense against these type of petamate, for instance. And so these disease, particularly controlled by cells, I guess. And what role does it play in temperature response?

It controls immune response. It doesn't control, you know, the growth or flowering. And these are other issues that, you know, plant scientists are working very hard, try to produce a new generation of so-called heat-tolerant crops that allow plants to grow in warmer regions or hot weather. In fact, the breeders are normally focused on growth and fruits and, you know, flowering, but our research suggests that we should now pay attention to the plant immune system as well, because it's very susceptible to warm temperature.

You know, you can grow all the plants you want to if the immune system is not strong or resilient, and, you know, we're not going to get to the expected year. So could we expect that climate change and global warming as it heats up is going to wipe out some food crops? That is a prediction, actually. We're very concerned about that. One reason is that a lot of crop plants don't flower at the time they're supposed to flower. You probably notice that the spring is very warm.

A lot of fruit trees flower really fast. And so then, you know, a freezing temperature coming to kill other flowers. A lot of times you don't even have a fruit that year. The same can happen for food crops and vegetables, especially cool weather crops, will have a serious challenges going forward. And you've been working on genes, testing different genes for a potential solution using gene editing that lets plants keep making the chemicals

they need to fight disease. Tell us about that. Yeah, so that's the main focus of the work. So once we find that salicylic acid is not produced enough, we want to know why, you know, why it's not producing enough. After many, many failed experiments, as you know, science like that, we eventually realized actually a gene we call CB60G, but it doesn't, it's not important. This gene actually function as like an immune master switch. At warm temperature,

it turns out this gene is not turned on for some reason. And then so once we figure out that, we basically did a repair experiment, modified a part of this gene to be temperature insensitive. So now the plants is able to switch on this master immune genes and then make salicylic acid and other defense systems allow plants to actually resist pathogens even at warm temperature. So I think this is the one solution. Obviously, there's additional solutions we and others exploring to basically make plants resilient to temperature so that they won't get sick. Amazing.

Can you give me the range of plants that this gene might help? Yeah, so we only worked on a particular plant called Arabidopsis. Okay, now, not that important to remember the name, but this is like a lab rat for plant research. That's the old mustard plant, right? Yeah, yeah. So a lot of scientists want to use this one because it's a typical plant, obviously, as all the, you know, traits that it has. But there's a lot of knowledge and research available to make a discovery fast. It is also relative of vegetables we eat.

So that's what we are working on. But obviously you want to know whether the phenomenon you discover is also occurring in crop plants. Fortunately to us, the gene, the immune master switch that we find is actually in all plants. So it's a pretty widespread. And we also tested several crops like tomato, rice, rapese. The salicyc acid system is also compromised at warm temperature. So this is pretty pervasive phenomenon in.

in plants, including crop plants. How much of a difference did it make when you were able to turn on that master gene? How much difference does it make in the plant fighting off for all its enemies? Yeah, so for instance, the plants around us was usually at 20, 21, 23 degree. That's what we normally do we increase temperature to 5, you know, by 5 degrees to 28. So normally, plants become really sick because the immune system is down. The modified plants we have able to fight as well as the normal plants would at the lower temperature. So we haven't tested limit of temperature we can go.

In general, we and others really want plants to have this robust temperature resilience, not only in a new response, but also, you know, setting the fluids and the flower time to be more resilient to temperature differences. So we can grow crops not only in one location, but in a new response. all over the world, right? You know, right now you heard about the importation, transportation, a lot of political issues that make the global food security and the issue. Can you imagine we can all grow food crop any way you want to, and then we'll really dramatically improve the condition we have. So that's what we're aiming for as a community of plant scientists. Can you tweak up the system and amplify the immune system rather than just bring it back up to

park and you strengthen it? Yeah, you can do this easily. We've done this in the laboratory, we and others. The problem with that is once you do that, plants actually cannot deal with perfectly, because essentially there's a phenomenon called defense and growth trade-off that if you devote too much energy to one thing, the other part of your system doesn't look very well. So you can hike up with the defense very high or, you know, all the other part of your system doesn't work very well. all the time, plants actually become very small.

And so that's not good. That's not what we want, right? We want to steal a lot of fluids, you know, a lot of biomass. And so there's a balance we need to achieve. We need to make sure that defense only up when we need it to. And we need a level of defense that's just enough so that we don't want to divert energy from other part of the plant life that it needs to cover. Yeah, I know because I know that herbicides work by getting the plant,

grow too quickly and it kills the plant, so you don't want to do that. I mean, how should we be thinking about the role of GMOs in our food system? I mean, this is going to be a genetically modified plant. I know some people are uneasy about them, but won't we need to consume more GMOs in our future diets if we're going to fight climate change? Yeah, so there's two answers to this. So our eventual goal is not to use GMO to this very early stage. What we want is really to find some alleles already in nature and by then introducing into the cultivar, like what conventional breeding is.

So the goal is to not make GMO. However, as a scientist, I know GMO is very safe. I mean, it's probably more safe than some of the natural food we eat. and I think public will eventually realize the GMO food is as safe as natural food. But again, you know, this is a debate that we're going to have for a long time, and we should allow different opinions, different choices. Again, the goal of the scientists is to find as natural approach as we can, but at the same time to come up with more nutritious and safe and affordable food

that we can eat or continue to eat, even though we're going to live in a very hot and harshly climate. I'm Ira Plato. This is Science Friday from WNYC Studios. Let's talk about the science here a bit. We talked about how temperatures impact the plant's immune system. What about all the other impacts of the climate crisis like drought, flooding, humidity? How might the plants fare against these?

Yeah, yeah. What you want is make a plant to be able to resist high temperature, drought, and high salinity, and these are all associated with climate change, which we should pursue that as a community, obviously. But in reality, you don't need to have a particular culture that resist to all kinds of stress, because we still grow plants, crop plants in a regional basis. So in this region, you know, maybe the hot temperature is the main issue. in another region, like in California or something, drought is a problem.

So we need to create a library of elite cultivar that can be grown in different places. And I think that's what we want to do. But yeah, drought, salinity are major problems. While you're worrying about the health of the plants and something that you should be worrying about, what about the health of the soil in climate change and the climate crisis, the microbes,

the microbiome in the soil? Yeah, the temperature and drought, especially, salinity has a huge effect on microbiome. Both the kind of microbiome, they're going to live there, and how they actually function. Microbiome is such a critical component of planthouse. So affecting microbiome could indirectly affect plant house. This is the whole biome. You know, plants not really just plant itself. It's actually living with a microbiome.

And so Michael Barron can be a solution because a lot of times Michael Barron can actually boost plant health and make plant more resilient to temperature and drought without actually our need to modify plant genome. So this is another non-GMO solution that we and others are looking at. That is. Yeah, yeah. That's crazy. That's terrific. It is crazy. It's very complex.

And so it would take a while to. figure out like a probiotic for plants, for instance. But our colleagues, my colleagues, working really hard on this. That's great. You know, we talked just a couple of weeks ago about the failures of wheat crops, both in the U.S. and globally this year. It seems like protecting food from climate change is increasingly urgent. I'm sure you would agree. When can we expect to see more temperature-resistant crops? When will you get some of your research to market, do you think? Right. So, you know, as a scientist, I don't want to speculate too precisely because a lot of things are a lot of control. But we want to, you know, obviously bring this seeing if we are well funded, you know, to continue to work on this.

Right now, the results in the laboratory, but we want to take this in the field testing. We'll take a few years. I would say within 10 years or so, the technology should be ready, right? and whether how many, you know, farmers are going to use it. That's kind of another level of complexity that is not really solvable by science. You have a type of policy change and think of all of that. But, yeah, so, you know, we do our best to bring the technology or the knowledge, at least, to people that this is actually feasible if we continue to invest.

But, you know, as worldwide, we need a, I always say, say a global Manhattan project, where governments, you know, put in really a lot of funding because agriculture is going to be huge critical issue for human survival. I mean, we're seeing it, as you said, climate change is here already. You need a, like, you know, big consortial people really dedicated to address this Manhattan project level of effort to solve all these problems, temperature, drought, salinity, you know, spooed security. I think this is the time to do it. Well, from your mouth to the world government's ears, I want to thank you for taking time to

be with us today. Thank you so much, Ira. Nice talking to you. Dr. Senyung-hee, Professor of Biology at Duke University and investigator at Howard Hughes Medical Institute. And a special thanks to McKenzie White, our AAAS fellow this summer, who produced this interview. One last thing before we go. Are you a plover lover? Now don't take it the wrong way. I mean, are you ready to tiptoe through the tide with us? Well, it suns out, puns out at our virtual trivia night this Wednesday, July 27th at 8.30 p.m. Eastern. Join us for an online quiz show all about our favorite beach birds, the piping plovers, RSVP on our website, Science Friday.com slash trivia. And here's Kyle Marin Viterbo with some of the folks who helped make

this show happen. Annie Niro is our individual giving manager. Nehima Ahmed is our manager of impact strategy. D. Peter Schmidt is our digital producer and I'm community manager, Kyle Marion Viterbo. Thanks for listening. Thank you, Kyle. BJ Leidman composed our theme music. And if you missed any part of the program or you would like to hear it again, yes, subscribe to our podcasts or ask your smart speaker to play Science Friday. You can always email us SciFri at Science. Friday.com. Have a great weekend. I'm Ira Plato.