ESF researchers plan to continue despite loss of foundation support for genetically engineered strain
By Chloe Bennett
Before the 1950s, American chestnut trees comprised a significant portion of deciduous Eastern forests. By then, nearly all of the grand, dominant tree population in the Northeast was affected by a fungus introduced to the United States from East Asia in the 1900s known now as chestnut blight.
Once reaching around 100 feet in height, most American chestnuts in the Adirondacks today grow only a few feet before succumbing to the blight, according to Adirondack Park Agency data. Researchers from various institutions have sought to introduce a blight-tolerant version of the tree, including the SUNY College of Environmental Science (ESF).
In 2015, after decades of research, the college began developing the transgenic Darling line, named after early supporter Herb Darling. Transgenic trees are genetically modified to overcome illnesses like chestnut blight or other interferences.
According to The American Chestnut Foundation (TACF,) the goal of the Darling line of trees “was to confer blight tolerance by inserting a gene from wheat called oxalate oxidase (OxO).” The foundation chose Darling 58 after a series of trials showed promise at preventing deadly cankers caused by the fungus.
But in December, The American Chestnut Foundation (TACF) announced it would no longer support the transgenic line developed by SUNY ESF because of performance issues and the risk of skewing public perception against biotechnology.
The foundation was involved since the beginning, said Andrew Newhouse, director of SUNY ESF’s American Chestnut Research and Restoration project.
But a labeling error made in 2016 is partly to blame for the foundation withdrawing its support for the project. The misidentification likely happened while the research team was moving the line for pollination work.
“We are just now understanding that the trees that we’ve been working with ever since 2016, that we’ve been calling Darling 58, are actually Darling 54,” Newhouse said. The difference between 58 and 54 is the location of the gene that modifies the plant, though they are nearly identical, Newhouse said.
Still, TACF said it will not support the development and regulation of the Darling line. The foundation also said it plans to work with SUNY ESF on other projects.
“We have left the door open to continued collaboration on other lines and projects and our organizations remain in consistent contact regarding future efforts,” Sara Fern Fitzsimmons, TACF’s chief conservation officer, told the Explorer.
In a release, Fitzsimmons said the Darling trees would not adversely affect the natural environment but could impair the future of disease-resistant American chestnut populations.
“Premature distribution of this or other inferior varieties also may unfairly skew public perception against biotechnology solutions to save threatened forest tree species,” she said in the release.
With almost $5 million invested in the Darling line, Newhouse said the research team plans to continue its work to restore the American chestnut tree. He estimated that about $1 million of its funding came from the foundation.
One scientist who has followed the research and news from TACF said he believes the foundation made the right call. “It’s pretty clear that the Darling has some real issues,” said Tom Langen, a biology professor at Clarkson University.
“That will turn the public off to the whole idea of using transgenics as part of the solution,” he said. “Even though, really, the issue is this particular transgenic line.”
Langen said SUNY ESF should continue its research while it and other institutions work on transgenic and hybrid American chestnut seeds. Newhouse said the team plans to study the Darling line and other projects.
The Adirondack Park may one day be on the list of locations where a transgenic American chestnut could thrive.
The iconic tree, found in many pieces of American art and literature, would reintroduce an important food source for a variety of wildlife and people. Many Indigenous groups in the U.S. stewarded the trees and used chestnuts for food and medicine.
Before the blight, the Adirondacks were not home to an abundance of the tree species, which preferred locations in and around Appalachia to the colder climate up north. However, warmer temperatures from climate change may alter the tree’s range.
“Our climate has already changed a lot compared to when chestnuts were prevalent prior to blight, and we expect it to continue changing, at least for the foreseeable future,” Newhouse said. “So, it’s likely that the Adirondacks would actually be a pretty promising part of future American chestnut ranges.”
In its announcement, TACF said the growth of Darling trees was limited and that they were inconsistent with blight tolerance and mortality rates. Still, the foundation acknowledged that it learned from the time and money spent on the SUNY ESF line.
Fitzsimmons said the organization plans to look primarily at transgenic lines with genes that are activated when needed. The Darling line had a promoter that kept the gene active constantly.
“An analogy I like is that it would be equivalent to running a diesel generator all the time at your house, just in case the power goes out,” she said.
But no single transgenic tree will lead the restoration process, she said. The foundation plans to deploy several products into forests to achieve restoration, which could take generations to accomplish.
Langen, who has followed the research from SUNY ESF and other institutions, remains optimistic that a transgenic American chestnut could become a fixture in Eastern forests.
“The lesson you don’t want to take from this is that it’s a waste of money to work on developing an American chestnut tree that’s resistant or that it’s an ecological risk to try to develop transgenic options for this,” he said. “In general, it’s promising. A lot of progress has been made.”
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