Once a dominant species of the eastern US, the American chestnut (Castanea dentata) was devastated early last century by the disease chestnut blight, caused by the fungal pathogen Cryphonectria parasitica which was recently detected in southwest England.
Now researchers at the College of Environmental Science and Forestry (ESF), part of the State University of New York, have planted 100 transgenic young trees which carry a wheat gene enabling them to withstand the blight in a "seed orchard"in upstate New York.
When they grow large enough to produce pollen, this will be used to fertilise the flowers from wild-type "mother trees" to preserve genetic diversity. Half of the resulting nuts will inherit the blight-resistance gene.
"They will be the basis of the trees we will eventually give out to the public," said ESF professor William Powell, who has led the project. "And they'll be the basis for the trees we will use for demonstration and research for the next 100 years."
Thought to be the first bid of its kind, it must first be reviewed by the US Environmental Protection Agency, the US Department of Agriculture, and the Food and Drug Administration - a process Powell expects to take two to four years.
"We are the first to ask for approval for a genetically engineered wild tree, the first to go through the regulatory process," he said. "We're paving the way for all the other trees that are affected by invasive species: ash, elm, hemlock and walnut among them."
He added that restoring the trees to the eastern forests "would affect a lot of wildlife - from bees to bears".
Powell and his team have developed a field test that can indicate which nuts contain the blight resistance gene and which do not within four hours.
"We've done enough research to know that the transgenic trees have no detrimental effects on leaf litter, insects or fungi," Powell said. "But we're doing further studies to build a body of knowledge that shows these trees will not harm the environment in any way."