Bananas are the world’s most popular fruit. Americans eat nearly 27 pounds per person every year, according to the U.S. Department of Agriculture. 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 growing bananas, RTP may not be the first place that pops in your head. But Matt DiLeo has a greenhouse full of them.
DiLeo is Vice President of Research and Development at Elo Life Systems, a biotechnology firm that's exploring how gene editing can improve fruits and vegetables.
On a cloudy afternoon in early April, DiLeo opened the greenhouse door and stepped into a steamy atmosphere with a slightly floral odor. This greenhouse is packed floor to ceiling with banana trees. You’ve got to duck to keep the giant leaves from hitting your face. Some of the bananas are yellow, some are green, some are tiny and pink. DiLeo says they all share an important trait.
“Many of these are naturally resistant to the TR-4 fungus," DiLeo said.
TR-4, also known as Fusarium Oxysporum, is a kind of fungus that attacks banana trees at the roots, killing the fruit. Fungicides and other chemicals can’t kill it, so farmers have few options when it invades their crop.
TR-4 was discovered in Southeast Asia about 50 years ago. By the late 2010s, it was showing up in the soil of banana producing countries like Columbia, which is home to the Cavendish banana — the variety you'll find at your local grocery store. Other banana-producing nations, like Costa Rica, have enacted strict biosecurity measures to prevent its spread.
DiLeo and his colleagues at Elo think they’ve found the solution to making a TR-4-resistant Cavendish banana. It’s called molecular farming — basically a form of gene editing.
Just upstairs from the greenhouse, DiLeo walks through a maze of laboratories, where dozens of scientists are hunched over workstations and microscopes. Their task is to understand how genes affect plant traits — like how the Cavendish banana is susceptible to the TR-4 fungus.
"One of the challenges about plants is that they grow very slow, it takes a long time to work with them. And so, we look for every opportunity we can to compress timelines, so that we can make better plans in the shortest time as possible,” DiLeo said.
In this case, it's taking genes from those bananas in the greenhouse and editing them into the DNA of the Cavendish.
“Bananas contain 30,000 different genes,” DiLeo said. “And each one of these genes helps a banana to do one thing that it needs to grow and survive in the environment. And what we do is we find those single genes that are broken, that make the banana susceptible to this disease, and we go in, and we fix that single gene."
There are more than a thousand banana species in the world, and many — like those we met in the greenhouse — are resistant to TR-4. But they don't produce enough fruit to feed the world's appetite.
In 2020, Elo entered a partnership with Dole, one of the world's largest fruit producers, to develop a banana that's resistant to TR-4 — and just happens to look and taste like the ones consumers are used to.
In another greenhouse, a few Cavendish banana plants are spread out in a room about the size of a bedroom closed.
"These are a mix of different gene edited plants that we've made, we expect some to be resistant, and some won't be resistant. And this is 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 years before they're ready for mass production. Elo isn't the only company wrestling with the TR-4 menace. Dole's main rival, Chiquita, is also working on a fungus-resistant banana. Another was recently approved for human consumption by regulators in Australia.
Even the United Nations is involved.
Its Food and Agriculture Organization hosted a World Banana Forum in Rome last month to come up with a global strategy to fight TR-4. It's not just a matter of satisfying the pallets of everyday consumers. For farmers in banana-producing nations, their very livelihoods are at stake.
This story has been updated to clarify that TR-4 has not been detected in Costa Rica.