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Fighting banana blight in a greenhouse in North Carolina

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A bunch of green bananas growing on a tree
Bananas grow in a greenhouse at Elo Life Sciences, an RTP company developing a genetically modified banana resistant to a deadly fungus that affects much of the world's banana crop, in Durham, North Carolina, Wednesday, April 3, 2024 . Photo credit: Ben McKeown, for WUNC

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This article is part of “The State of Science,” a series of science reports from public radio stations across the United States. This story by Bradley George was originally published by WUNC.


Bananas are the most popular fruit in the world. According to the U.S. Department of Agriculture, Americans eat nearly 27 pounds per person each year. A deadly fungus could destroy most of the world's crops, but a company in Research Triangle Park is trying to save the banana through gene editing.

When it comes to banana farming, RTP may not be the first place that comes to mind. But Matt DiLeo has a greenhouse full of them.

DiLeo is vice president of research and development at Elo Life Systems, a biotechnology company that studies how gene editing can improve fruits and vegetables.

On a cloudy afternoon in early April, DiLeo opened the greenhouse door and entered a steamy atmosphere with a slightly floral scent. This greenhouse is filled from floor to ceiling with banana trees. You have to duck to avoid the huge leaves hitting you in the face. Some of the bananas are yellow, some are green, some are tiny and pink. DiLeo says they all have one important quality in common.

“Many of them are naturally resistant to the TR-4 fungus,” DiLeo said.

Bananas grow in a greenhouse at Elo Life Sciences, an RTP company developing a genetically modified banana resistant to a deadly fungus that affects much of the world's banana crop, in Durham, North Carolina, Wednesday, April 3, 2024 . Photo credit: Ben McKeown, for WUNC

TR-4, also known as Fusarium Oxysporum, is a species of fungus that attacks banana trees at the roots and kills the fruit. Fungicides and other chemicals cannot kill it, so farmers have few options when it invades their crops.

TR-4 was first discovered in Southeast Asia about 50 years ago. In the late 2010s, it began appearing in the soil of banana-growing countries like Colombia and Costa Rica, which are home to the Cavendish banana — the variety you find in your local grocery store.

DiLeo and his colleagues at Elo believe they have found the solution to producing a TR-4-resistant Cavendish banana. It's called molecular farming – basically a form of gene editing.

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Just above the greenhouse, DiLeo walks through a laboratory labyrinth in which dozens of scientists sit at workstations and microscopes. Their job is to understand how genes influence plant traits – such as how the Cavendish banana is susceptible to the TR-4 fungus.

“One of the challenges with plants is that they grow very slowly and take a long time to work with. “That’s why we’re looking for every opportunity to shorten timelines so we can create better plans in the shortest amount of time,” DiLeo said.

In this case, it involves taking genes from these bananas in the greenhouse and incorporating them into the Cavendish's DNA.

“Bananas contain 30,000 different genes,” DiLeo said. “And each of these genes helps a banana do one thing it needs to grow and survive in the environment. And what we do is we find individual defective genes that make the banana susceptible to this disease, and then we go in and repair that individual gene.”

Two scientists in lab coats perform genetic tests with pipettes
Scientists work in the laboratory of Elo Life Sciences, an RTP company that is developing a genetically modified banana that is resistant to a deadly fungus endemic to much of the world, Wednesday, April 3, 2024, in Durham, North Carolina Banana harvest is widespread. Photo credit: Ben McKeown, for WUNC

There are more than a thousand species of bananas in the world and many – like the ones we met in the greenhouse – are resistant to TR-4. But they don't produce enough fruit to satisfy the world's appetite.

In 2020, Elo partnered with Dole, one of the world's largest fruit producers, to develop a banana that is resistant to TR-4 – and just happens to look and taste the same as consumers are used to.

A man holds a plastic container with a small green plant in his hand
Matt DiLeo, vice president of research and development for Elo Life Systems, holds a plant specimen at Elo's RTP facility in Durham, North Carolina, on Wednesday, April 3, 2024. The company is developing a genetically modified banana that is resistant to a deadly fungus that sweeps through much of the world's banana crop. Photo credit: Ben McKeown, for WUNC

In another greenhouse, a few Cavendish banana plants are spread out in a space about the size of an enclosed bedroom.

“This is a mix of different genetically modified crops that we have created. We assume that some are resistant and others are not. And that’s how we identify which ones can withstand the disease,” DiLeo said.

Dole is ready to test Elo's bananas on farms in Honduras, but it will be a few more years before they are ready for mass production. Elo is not the only company struggling with the TR-4 threat. Dole's main competitor Chiquita is also working on a fungus-resistant banana. Another was recently approved for human consumption by Australian regulators.

Even the United Nations is involved.

His Food and Agriculture Organization hosted a world banana forum in Rome last month to develop a global strategy to combat TR-4. It's not just about satisfying the palettes of everyday consumers. Farmers in banana producing countries have their livelihoods at stake.


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