By Caroline Wells
Would you eat something from a plant knowing it has been genetically altered? At what point should we allow for the genetic modification of food-producing plants? This question becomes prevalent when considering methods scientists are using to revive populations of organisms facing disease, such as the American chestnut tree.
American chestnut trees are large trees, extremely important not only to the ecosystem but to humans as well. The tree’s size and rot-resistant properties led to the widespread use of sturdy American chestnut wood for many structures, and its nuts were a common food source as well. American chestnut trees once covered the entire east coast of the United States; until a foreign fungal infection known as “chestnut blight" took over, wiping out entire populations of the plant and rendering it extremely close to extinction. However, scientists today are working to reverse this using two methods: traditional cross-breeding and transgenics.
What is the cross-breeding method?
Scientists working to achieve blight-resistant American chestnut trees can cross-breed the specific species with a naturally resistant chestnut tree species, a commonly used example being the Chinese chestnut tree. The new generation of the American-Chinese chestnut tree cross is then bred again with American chestnut trees in order to regain its original traits. When this is done, only 1/16 of the tree is still genetically the Chinese species, but it has been shown to make
it more resistant to the disease.
What is the transgenic method?
Transgenic is a term used to describe an organism that is genetically altered with DNA from a different species. In the case of the American chestnut tree, scientists have been experimenting with wheat genes and inserting them into the tree’s DNA. Specifically, genes coding for the enzyme oxalate oxidase are inserted, this provides the tree with the ability to break down the deadly oxalic acid released by the the chestnut blight With this modification, the trees would have a line of defense against the pathogen t increasing survival and resistance to infection . Results have shown this method to be more effective than cross-breeding in building resistance to the blight: the newly produced trees are likely more immune than purely bred Chinese chestnut trees. This method has been proven to aid organisms other than the American chestnut to combat widespread disease as well, such as potato crops. So, is transgenics the future
for tree preservation?
Unfortunately, it’s much more complicated to enact transgenics than the traditional cross-breeding method. There is still a relatively high level of caution and stigma surrounding the use of genetic altering, especially when considering fruit producing plants such as the chestnuts. The transgenic American Chestnut tree, otherwise known as the Darling 58, must receive approval through the USDA, EPA, and FDA before it can be released and used to plant more blight
resistant trees. This is an extremely long and frustrating process, but scientists hope to complete it by 2023. Is the preservation of American chestnut trees worth scientists preserving through such a long and rigorous process?
Sources
The Great American Chestnut Tree Revival. Modern Farmer. (2022, January 12). Retrieved March 13, 2022, from https://modernfarmer.com/2021/12/the-great-american-chestnut-tree-revival/
To save iconic American Chestnut, researchers plan introduction of genetically engineered tree into the wild. Science. (n.d.). Retrieved March 13, 2022, from https://www.science.org/content/article/save-iconic-american-chestnut-researchers-plan-introduction-genetically-engineered-tree