Chestnuts harvested from high branches on a chilly fall morning look typical: they’re marble sized, russet colored and nestled in prickly burs. But many are like no other nuts in nature.
In a feat of genetic engineering, about half the chestnuts collected at this college experiment station feature a gene that provides resistance to blight that virtually wiped out the American chestnut tree generations ago.
Researchers at New York state’s College of Environmental Science and Forestry will soon seek federal clearance to distribute thousands of modified trees as part of a restoration effort — a closely-watched move that could expand the frontier for genetically engineered plants beyond farms and into forests. The precedent-setting case adds urgency to a question scientists have already been grappling with:
Should genetic engineering be used in the wild to help save or restore trees?
Opponents warn of starting “a massive and irreversible experiment” in a highly complex ecosystem. Proponents see a technology already ubiquitous in the supermarket that could help save forests besieged by invasive pests.
“We have this technology, it’s a very powerful technology, and we can use that now to save a species,” said Professor William Powell, a molecular plant biologist who directs the American Chestnut Research and Restoration Project at the college.
The researchers will ask the U.S. Department of Agriculture to assess an American chestnut tree with a gene from wheat that helps it tolerate cryphonectria parasitica, a fungus unwittingly imported to the United States over 100 years ago.
The blight decimated a towering tree species once dominant in forests from Maine to Georgia. Nuts from up to 4 billion trees fattened farm animals, and its sturdy wood was used to build cabins. Yet by the end of World War II, trees were doomed by the blight. Surviving trees today are typically shrubs sprouting from old roots, yet to be infected.
Powell and his research partner Charles Maynard began working on a complementary track decades ago at the request of the New York chapter of the American Chestnut Foundation. The added wheat gene enables trees to produce an enzyme that breaks down harmful acid released by the fungus.
The USDA commonly authorizes genetically engineered crops. The vast majority of commercial corn and soybean acreage in the United States is used to grow crops engineered to be tolerant to herbicides or insects. There are even some genetically engineered plantation trees, such as papayas resistant to ringspot virus.
But engineered trees are not intentionally planted in the forests for conservation. That could change as genetic manipulation becomes more common and trees are increasingly threatened by invasive pests.
Some scientists are concerned about the long-term effects of a re-introducing a tree into the woods that can live for more than 200 years. How will the new trees interact with the species that replaced the long-gone chestnuts? What if the trees die off again in 50 years?
Meanwhile, trees are dying from scourges such as the emerald ash borer and the spotted lantern fly, and some scientists say biotech could help where other efforts have failed.
If the application clears the USDA, the tree still needs to be considered by the Food and Drug Administration and it may need to be reviewed by the Environmental Protection Agency. Powell believes the review could take two to four years.