Anisa Khalifa: We eat a lot of bananas. It’s the most popular fruit in the US, with nearly six and a half billion pounds consumed each year. But all those bananas are in big trouble.
Unidentified Speaker: I had no idea that bananas were even under threat from a fungal disease.
Anisa Khalifa: I’m Anisa Khalifa. This week on the Broadside, what a biotech company in North Carolina is doing to save the fruit from extinction.
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Anisa Khalifa: Okay, you’re in the grocery store — the produce section. And you’re running through your list…
Charlie Shelton-Ormond: I'm gonna get one orange…actually, I need a lemon as well.
Anisa Khalifa: I'll get it. You want to add some apples to the cart. But which kind…
Charlie Shelton-Ormond: You want a honeycrisp?
Anisa Khalifa: Sure.
Charlie Shelton-Ormond: Okay great.
Anisa Khalifa: And then, toward the back, you see a wave of yellow. Or maybe green. The bananas.
Charlie Shelton-Ormond: Yeah, can you grab two bunches of those?
Anisa Khalifa: But, unlike those apples, there’s really only one kind of banana to choose from. Sure, you might spot some plantains nearby, but those bright yellow bananas found on the shelf and in your pantry… they’re all the same variety.
Andrew Zaleski: Any banana that you buy in a store, and I'm speaking specifically about the U. S. here, is something called the Cavendish banana
Anisa Khalifa: Andrew Zaleski is a contributing writer for Bloomberg Businessweek. He recently wrote a piece about the Cavendish banana, even though…
Andrew Zaleski: I don't like bananas myself.
Anisa Khalifa: Ooh, I also don't like bananas!
Andrew Zaleski: Yeah, no I eat apples and pears and blueberries, but not bananas.
Anisa Khalifa: For the piece, Andrew looked into why the Cavendish is king in the banana industry. And how an ominous fungus lurking within the soil is threatening its reign.
Andrew Zaleski: The villain here is a fungus called Fusarium.
Anisa Khalifa: Fusarium dwells in the soil and enters a banana plant through its roots, slowly invading the entire plant, and eventually suffocating it.
Andrew Zaleski: When it comes to the Cavendish banana, Fusarium wreaks utter and complete havoc and just murders the thing.
Anisa Khalifa: For decades, Fusarium has trekked through banana fields across the world – from Southeast Asia to the Middle East, and into Africa. In 2019, farmers and scientists spotted the banana-killing fungus in Colombia, a major producer of the global banana supply.
Andrew Zaleski: Latin America is where the majority of Cavendish bananas for export are grown. And Cavendish bananas make up 99 percent of global banana exports.
Anisa Khalifa: The specific strain of Fusarium that's wreaking havoc on the Cavendish is called Tropical Race 4, or TR4. The scary thing is, there’s no remedy to naturally get rid of it.
Andrew Zaleski: And then you don't have any bananas because the plant has been wiped out.
Matt DiLeo: We have lots of bananas. There are wild bananas where there is fruit on them…
Bradley George: Oh wow. It smells like a flower nursery in here.
Anisa Khalifa: But the Cavendish isn’t going out without a fight. In Durham, North Carolina, a group of scientists are working to strengthen the plant against TR4.
Bradley George: So I'm standing in an office park in the middle of RTP surrounded by banana plants, which it's wild to think that there's somewhere in North Carolina growing bananas, because this is not the climate for it, at all. That's correct.
Anisa Khalifa: Recently, my colleague Bradley George visited Elo Life Systems—a biotech company focused on gene editing for crops. It’s located in the Research Triangle Park here in North Carolina.
Matt DiLeo: Every cell in your body can have very small natural mutations. The same thing happens in plants. And so for example, if you take lots of cuttings of plants in your garden, none of them are exactly the same.
Anisa Khalifa: Bradley got a tour from the company’s VP of product development, Matt DiLeo. They checked out Elo Life’s greenhouse and the plants they hope will one day rescue the Cavendish.
Matt DiLeo: Many of these are naturally resistant to the TR4 fungus. They just don't have the fruit quality or the yield that's required to ship to a northern hemisphere market.
Anisa Khalifa: Here’s how it works. First, Elo Life studies lots of different types of bananas, to see which ones are resistant to the TR4 strain.
Matt DiLeo: Yes, these bananas are all naturally resistant to TR4, so what we did is we went into their genomes, understood what was different about their genes that made them resistant,
Andrew Zaleski: They selected about a hundred targets. The banana itself, this is, this is a little wild. It has like more than 30, 000 genes, which is more than a human has. And then they take that number, they narrow it down to a hundred and they test those.
Matt DiLeo: And then we took the Cavendish banana and only fixed those specific genes so that they would still have the fruit quality and yield, while also now being resistant to TR4.
Andrew Zaleski: If they are resistant, then it goes over to another lab where they actually create the bananas. They try to create these fusarium resistant bananas.
Matt DiLeo: one of the things that's devastating about this disease, is that it's in the soil. So you can't spray a chemical to protect the plants, you can't remove it, it lives there for years and years and years. And so the only solution is to find bananas that are resistant to the disease genetically.
Anisa Khalifa: It’s a lot of work for one banana. But remember, the Cavendish is essentially a monoculture for the commercial banana industry. That means there's a single dominant variety in the entire world. So… what makes it so special for mass production? Why’s it the only one we see on the shelf in grocery stores?
Andrew Zaleski: The Cavendish banana, it's hardy. It travels well. It doesn't ripen too quickly. So by the time it reaches its destination, it's not gross.
Anisa Khalifa: But Andrew Zaleski says relying on just one variety can be risky…
Andrew Zaleski: If you have the same banana with the same genetic structure, the same genome, and you're planning, you know, You know, hundreds of thousands of these bananas and then some sort of disease comes in that attacks one of them. It's going to attack all of them. It's just going to get them all. There's no genetic diversity there to kind of offer some sort of layer of protection. You know, it's just game over.
Anisa Khalifa: Walking through Elo's greenhouse, our man on the ground, Bradley George, wondered about the long-term viability of banana editing.
Bradley George: So is there a risk then that at some point TR4 itself will change and then your variety of banana will maybe become susceptible?
Matt DiLeo: Yes, there's absolutely a possibility and that's something that, uh, that's common in agriculture is that you have to keep finding new varieties to protect you from new pathogens.
Anisa Khalifa: Elo Life’s gene editing is a new approach to try and save this essential crop. It’s a method scientists and farmers didn’t have access to the first time the banana faced extinction. That’s coming up after a short break.
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Anisa Khalifa: So, Andrew, This isn't the first time the banana has been faced with total annihilation. When else did we see the rise and fall of a specific type of banana?
Andrew Zaleski: The backstory of bananas is interesting unto itself. There's a great writer, and I apologize Dan, if you listen to this and I mispronounce your last name, Dan Koeppel, he wrote a great book called Banana: The Fate of the Fruit that Changed the World. And in that book he talks about how the banana trade in the U. S. even started out. So it starts out this seafaring captain coming back from Jamaica in 1870. He brings over all these bunches of banana called the Gros Michel, or Big Mike, basically. And Gros Michel was the banana in the U. S. And according to people who have, who have tasted it before, it's sweeter. It's better in most respects. It's better than the Cavendish.
One of the scientists that I interviewed for the story actually told me, if you have like banana flavoring, it's Gros Michel flavoring. It's not Cavendish flavoring, because the Gros Michel is sweeter. But anyway, this is the banana that, uh, Standard Fruit, which is today Dole, and United Fruit, now Chiquita, were planting in Latin America, you know, throughout the late 1800s, early 1900s. But the Gros Michel was susceptible to another fusarium strain known as Race 1 that jumped over the Pacific, gets into the Latin American Gros Michel fields, and starts wiping out those bananas. And by the 1960s, these companies have switched over completely to the Cavendish, because the Cavendish is resistant to the Race 1 strain. And that's sort of the story there. There was this other banana that everyone loved, gets killed by a fusarium strain, they switch over to the Cavendish and now, like a broken record, we're sort of repeating the process.
Anisa Khalifa: Okay so, we see the Gros Michel die out in the 1960s, let’s jump about 20 years later in the 1980s, back to Durham, North Carolina. That’s when something pretty historic in food science happened in the same building where Elo Life is located, right?
Andrew Zaleski: Yeah… Elo's labs are actually located in the same building where Mary Dell Chilton did her work. And Chilton, uh, in the early 80s, she created the first genetically modified crop. She inserted a yeast gene into a tobacco plant. And then spent decades at a company called Syngenta. And, you know, Syngenta was the company that was first to commercialize BT corn. Um, and that's, that's the corn that's been genetically modified to basically express this protein that will kill larva of corn borers instead of the larva actually hatching and killing the corn. So, yeah, I mean, it is kind of interesting how that is the place where Elo is doing this work and for years it was, it was kind of the, uh, the brain trust where Mary Dell Chilton was, and I mean, you know, she's the leader in bioengineered crops. She's the person who did it first.
Anisa Khalifa: Andrew, you and I both are not fans of bananas. I know there are plenty of people out there who do like them. But for the people who don’t have bananas in their pantry, how does this story still affect them?
Andrew Zaleski: More often than not, these sort of genetic modification approaches, they could be applied to other things. People get scared of hearing genetically modified in any context. All it means is you're manipulating a gene. You're trying to give some sort of resistance to a plant. No one's putting anything inside of you. You're not going to be sick from eating this banana. If you know how to do it in this one fruit, there's always the possibility that some fruit in the future that millions of people rely on is also going to become susceptible to some other bacteria.
The other thing is, we sort of take Cavendish bananas for granted in the U.S. Down in South America it is a subsistence food. People grow this also because they need food. If all of the Cavendish die, that's kind of a bigger problem than just, you know, being at Wegmans and going, Oh, no bananas anymore. All right. I guess it's time to eat a pear. So it does matter. It matters outside of just the general context of people in America who like bananas and want to go get some on a Saturday morning, let's say.
Don't despair if you love bananas. If you're not like me and you like bananas, don't worry, they'll be around. There's lots of good work happening. Lots of smart scientists hacking the problem, so to speak.
Matt DiLeo: It's such an important part of people's lives. It's affordable. It's in, you know, every grocery store and convenience store you go to. And, you know, there will be a time where they won't be there anymore if a group like ours isn't able to create a resistant variety.
Anisa Khalifa: Back at the greenhouse in Durham, Elo Life’s Matt DiLeo told reporter Bradley George that these genetically modified banana plants aren’t growing just in the labs anymore …
Matt DiLeo: We've been producing batches of edited bananas over time. And so the first batch is growing in field trials in Honduras and they'll be harvested in late spring, early summer. Our partners at Dole will harvest the fruit and fully characterize its qualities and yield to see if it matches 100 percent what they need from the Cavendish, while also being resistant to the disease. And so hopefully one of the bananas we showed you today will one day be the bananas that we all eat.
Bradley George: Yeah. That's what I'm thinking about. Like someday I'll be in the supermarket, pick up a banana and be like, wow, I saw, I saw one of your ancestors, several years ago.
Anisa Khalifa: This episode of The Broadside was produced by Charlie Shelton-Ormond, who ate several bananas as he put it together. Special thanks to Bradley George for contributing to this episode. Our editor is Jerad Walker, who is a big strawberry-banana smoothie fan. Our executive producer is Wilson Sayre.
The Broadside is a production of WUNC–North Carolina Public Radio. You can email us at broadside@wunc.org. If you enjoyed the show, leave us a rating, a review, or share it with a friend! I’m Anisa Khalifa. Thanks for listening y'all. We'll be back next week.