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Tuesday, May 02, 2023

Feds still mulling old request to test gene-modified chestnut trees in the wild; to play God after playing the Devil?

A horse chestnut tree
(Photo by Jean Mottershead, flickr.com via CC)
Eastern U.S. forests were once full of chestnut trees, but they are gone, and only science can replace them. "The majestic trees grew as much as 100 feet tall and 10 feet wide. . . . Over the 20th century, an estimated four billion of them, one-fourth of the hardwood trees growing in Appalachia, were killed by an Asian fungus accidentally imported in the late 19th century," recounts Sarah Gibben of National Geographic. "It's considered one of the worst environmental disasters to strike North America—and also a preview. . . . Emerald ash borer, sudden oak death--in a globalizing world, many trees are facing pandemics of their own."

Given the mass loss and desire to reestablish part of native Appalachia, some efforts have been launched to grow blight-proof chestnut trees. They're still trying. Tom Saielli, a forest scientist for the American Chestnut Foundation, told Gibbens, "Fast-forward 30-plus years of breeding work, and what we see is, blight resistance is much more complicated than we really thought."

The crux of the problem is the insidious infecting fungus, Cryphonectria parasitica, which releases oxalic acid; the acid kills adult chestnut trees, so efforts to hybridze them with Chinese chestnuts failed around the time the hybrid trees were 15 years old. Then reseearchers found "a wheat gene that enhanced pathogen resistance in tomatoes" and produces "an enzyme that breaks down the acid produced by the blight fungus, rendering it harmless," Gibben reports. They added the gene to the chestnut's genome and produced a modified tree that they named Darling 58. "Trees grown in test plots proved tolerant of the blight."

Researcher Bill Powell of the SUNY College of Environmental Science and Forestry in Syracuse, N.Y., "is confident Darling 58 is safe, but transgenic trees inspire a fear of the unknown," Gibbens writes. "In 2014, chestnut fans wanted to know when they could get Darling 58. Eight years later, they’re still waiting. . . .Who can grow genetically modified crops and where they can be grown are tightly regulated in the United States. Powell and his colleagues have asked the Department of Agriculture, the Food and Drug Administration, and the Environmental Protection Agency to deregulate Darling 58, affording it the status of a non-modified tree. . . .Anne Petermann, executive director of the Global Justice Ecology Project, told Gibbens, "Once these are out in the forest, there's no calling them back. There's no way to reverse it." Allen Nichols, president of the New York chapter of the chestnut foundation, told Gibbens, "Some people say, 'You're playing God,' What I say is: 'We've been playing the devil for ages, so we need to start playing God, or we're going to start losing a whole mess of stuff.'"

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