The kind of tree that was once abundant in the US (Wikimedia commons)
For years, public sector scientists have been working on a remedy for the disease-related near extinction of the American Chestnut which was once the dominant large tree in the forests of the Apalacian mountains. I've heard updates about this over the years at "biotech bootcamp" events and I admire the patience and resolve that they have demonstrated in this ambitious effort. Here is what I wrote to the agency:
Submitted Sunday 8/23 tracking # 1k4-9ijy-kaf2
I am writing in support of the petition for deregulated status for a transgenic American Chestnut event which has been submitted by the State University of New York College of Environmental Science and Forestry. This submission is the culmination of a long-term effort to develop a means by which this key forest species could be restored to its historical role in the forest ecosystems of Eastern North America - a role that has been seriously compromised since the accidental introduction of a fungus which is a deadly pathogen of Chestnuts. Although it will certainly take a long time to re-establish such a long-lived species, this strategy is the best hope we have of achieving that very desirable environmental outcome.
My graduate training was in the field of plant pathology at UC Davis in the late 1970s and early 80s, so I can appreciate the challenge of counteracting this disease of this in natural forest settings. Since that time, I have also had the opportunity to closely follow progress in the science of plant biotechnology in both academic and commercial research. The decades of experience that now exist concerning the safe and beneficial applications of transgenic technology in global agriculture demonstrate that broad deployment of this advance in a forestry setting is also something that can proceed without any undesirable or unmanageable outcomes. Indeed, as other commenters have noted, reestablishment of this species could be expected to contribute significantly to carbon sequestration and thus help to address climate change. (see https://pubag.nal.usda.gov/catalog/757823). This sort of solution also needs to be considered for other cases where introduced exotic pests compromise the health of our forests ( see https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6680343/)
It is significant that this project has been carried out by non-commercial entities simply focused on environmental goals. As an indicator of that, the event in question ("Darling 58") was never patented. The plan has always been to make that and related lines available for free for backcrossing into lines from multiple public Chestnut breeding and restoration efforts. Many of the other comments that have been submitted to APHIS about this petition are from those researchers who are awaiting the opportunity to be involved in those next steps.
The gene that was chosen for insertion into chestnuts is for the very commonly occurring enzyme Oxalate Oxidase or "OxO." It has always been a part of the plant genome and the human diet so there are no anticipated problems if it is expressed in reintroduced trees. The enzyme is not fungicidal itself but rather detoxifies a chemical that the fungus produces to weaken the Chestnut tree's defense mechanisms. That kind of trait is less likely to select for resistance, something that is very important since re-establishment will be a long-term project. It is also logical that the trait will be backcrossed into many Chestnut lines to insure sufficient genetic diversity since this species will face the need for adaptation to climate change and other challenges.
In the absence of negative outcomes from decades of plant biotechnology, the main objection to projects such as this tends to be based on the "precautionary principle" - the idea that there is no proof that nothing undesirable could ever occur. As such, that objection fails to consider the consequences on not employing the technology. In this case inaction would mean that important forest ecosystems will continue to lack the natural "keystone species" which is so important for the wildlife to thrive as it once did in these areas. The objection to human intervention in a natural system is also flawed in that human activity has already occurred with the introduction of that destructive pest. Indeed, it makes sense to employ the best solutions available to us as humans who strive to be good stewards of our environment. The deregulation of this transgenic event by APHIS is an excellent next step towards that goal.