In America the American Chestnut has been called the Redwood of the East. It’s trunk soared 100 feet high and could reach 10 feet in diameter. With crowns that spanned a fifth of an acre, its prodigious nut crops were essential food for everything from bears to pigeons. It was known as the cradle to the grave tree because people were born in rot resistant Chestnut houses, warmed by Chestnut fires, entertained by Chestnut fiddles and laid to rest in Chestnut coffins.Then in 1876, a nurseryman imported some Japanese Chestnut seeds that carried a fungus in which the American Chestnut had no resistance. The blight was discovered in 1904 at the Bronx zoo and it spread with shocking speed. By 1950, four billion American Chestnuts- 99.9% of the species had died, their bark ripped open to reveal a sickly orange rot girdling their trunks.In the New York Botanical Gardens there are three genetically modified Chestnut trees with a sign at the base of the trees ~ American Chestnut Trial, Castanea Dentata, Darling 4. Born in a lab in Syracuse, Darling 4 was engineered by geneticist who inserted a wheat gene into a wild Chestnut embryo extracted from an immature nut. The gene gives the Chestnut the ability to make an enzyme that detoxifies the blight – a skill none of the four billion American Chestnuts preceded it ever developed.Darling 4 doesn’t make enough of the enzyme to stop the blight completely, but its successor, Darling 58 – currently flourishing on a research farm at the State University of New York College of Environmental Science and Forestry in Syracuse – does. The goal is for the new tree to be distributed to nurseries and planted in forests throughout the East marking a major milestone in the story of GMOs.
Before it can be released into the wild the transgenic Chestnut has to pass a battery of ecological tests at SUNY designed to ensure that it acts like a natural Chestnut. Then it must be approved by the United States Department of Agriculture, the Food and Drug Administration and the Environmental Protection Agency. So far the tree has excelled in all the tests. Approval is looking likely.
Research on genetically engineered trees has been with species commonly used in industrial plantations – poplar, pine and eucalyptus – and has focused on engineering traits that would boost profitability, such as disease resistance, insect resistance, herbicide tolerance, cold tolerance and faster growth. In this they have mirrored the development of GMO crops, and they have drawn similar criticisms.
Resistance to genetically engineered trees has been strong with the ‘Campaign to Stop GE Trees’ leading the charge. To date only a handful of transgenic have made it to field trials, including frost tolerant eucalyptus trees and fast growing poplar and eucalyptus and only two have had significant commercial rollout: an insect resistant poplar in China and transgenic papayas in Hawaii and China. ArborGen, the company that invented the cold tolerant eucalyptus, petitioned the USDA for clearance to farm the tree in the US back in 2011, but it is still waiting a ruling.
The genetically engineered Chestnut is different as no one is seeking to profit from it. Its only purpose is to save a beloved species from extinction.
Darling 58 is now being crossed with the surviving wild Chestnuts via hand pollination, to produce a line of hundreds of unique trees that will embody the full breadth of America Chestnut biodiversity. These trees will have the full suite of 38,000 native Chestnut genes. Later this year SUNY will submit its application to release the Chestnut to the EPA, the FDA and the USDA. If the agencies all approve, seedlings could be ready for distribution by 2021.
The scientists at SUNY have tested as many aspects of its interactions with its future environment as possible. They’ve checked to make sure mycorrhizal fungi colonise its roots normally. They’ve confirmed that grasses, shrubs, pine trees and maple trees will germinate in its leaf litter. They’ve fed its leaf detritus to insects and tadpoles and they’ve let bees feast on its pollen.
In all the tests, there have been no difference between the transgenic Chestnut and the wild Chestnut.
Yet even though the Chestnut is being developed for the public good, the ‘Campaign to Stop GE Trees’ has raised concerns that it will open the door to commercial entities with less benevolent plans.
Ash trees are now dying. They’ve been attacked by the emerald Ash borer, an Asian beetle that arrived in Michigan 20 years ago in a packing shipment killing 99.7% of Ashes in its path, hundreds of millions of trees.
The Ashes are just the latest victims. The needles of nearly every hemlock are clumped with white waxy balls produced by the woolly adelgid as it sucks their sap. Most Eastern hemlocks from Canada to the Smoky Mountains will soon be grey ghosts. The American Elms are already gone having succumbed to Dutch Elm disease long ago. The grey bark of Beech trees are cankered with Beech bark disease.
All these declines are due to introduced species or insects or fungi to which our native trees have little resistance. The impact on our forests is massive.
So perhaps if the Darling 58 Chestnuts get their approval, they will grow tall, spread their crowns and when autumn comes drop their bounteous crop of nuts. The wildlife feeding on them won’t give a thought to the unusual coil of DNA keeping these trees alive. They’ll just eat and settle into autumn and life will go on.
Reference: https://psmag.com/ideas/most-controversial-tree-in-the-world-gmo-genetic-engineering
Images by Jason Holley.
Tree Weaver 