Cracking the Nut on Genetically Engineered Trees

What follows are two essays reflecting differing viewpoints on the topic of genetically engineered (GE) Chestnut trees. In the first column, Eric Evans of the American Chestnut Foundation, gives some history and context around the long and slow project to breed blight resistant American Chestnuts. He suggests that genetic engineering could shortcut that process and save valuable time, so long as it is done cautiously. In the second column, Fedco Trees’ Branch Coordinator, Jen Ries, argues that, no matter how much caution is used, once the door is opened to industrial scale restoration plantations of GE trees, it would be impossible to close. We would not have a complete understanding of the consequences of introducing these novel organisms into our ecosystems for decades, by which point any damage caused would be irreversable. Furthermore, the precedent set here would open the door to ever more industrial scale plantations of these novel organisms with unforeseen impacts on us all. We hope these essays help illuminate this complicated and weighty issue.

Breeding for Blight Tolerance

by Eric Evans, Back-cross Breeding Coordinator, Maine Chapter of The American Chestnut Foundation

American chestnuts are wonderful trees, and their decline throughout eastern states due to a fungal pathogen from Asia in the early 1900s was one of the worst ecological disasters in our country’s history. Development and distribution of blight-tolerant American chestnuts is a many-step, many-year process, using state-of-the-art science in breeding, silviculture, pathology, and molecular genetics. Eager to plant blight-tolerant American chestnuts, many Fedco readers have been following the progress of The American Chestnut Foundation’s (TACF) breeding program. In the last few years there have been profound changes in these prospects. It is time now for a summary of the history, current status, and likely paths forward.

Since its founding in 1983, TACF has been coordinating a six-generation back-cross breeding program, both in TACF’s research farms in Meadowview, VA, and in a dozen state chapters, including Maine. Chinese-American hybrid chestnuts were crossed back to American trees to dilute the unwanted Asian chestnut traits. At each back-cross generation, the Asian blight-resistance can be identified and the best trees saved for further back-crossing. TACF’s founders based the program on research that suggested that blight resistance in Chinese chestnut is relatively simple and controlled by just two or three genes. This would have allowed recovery of blight resistance in each back-cross generation while also maintaining all other American traits.

However, last year TACF scientists reported that blight resistance is a much more complex trait than originally thought, and that it is controlled by many separate genes on at least nine chromosomes. The best 6th-generation Meadowview trees are less blight-resistant than Asian chestnuts and less American than the natives.

The Maine Chapter of TACF plans to complete the planting of 6,000 more trees from our back-cross orchards (4th-generation) into our seed orchards in the next 2–3 years, for a total of more than 50,000 trees. Using more stringent selection criteria based on genetic tests as well as field observations, we will remove the poorest of the 40 breeding lines from the existing seed orchard plots and from future planting plans. Our goal will be to find the best balance between increasing blight tolerance and maintaining American traits and high enough genetic diversity for wide adaptability in forest plantings. We expect to have trees from this program for extensive field and lab testing starting in about 2023.

In addition to this back-cross breeding, TACF is supporting work at State University of New York, College of Environmental Science and Forestry to develop disease-resistant chestnuts using genetic engineering (GE). They have added a single gene from wheat to the chestnut genome that produces an enzyme, oxalate oxidase (OxO), that neutralizes the oxalic acid that the blight fungus produces in its attack on chestnut bark. The result is trees that are blight-tolerant but are otherwise 100% American chestnut. Studies have revealed no differences between the trees with the OxO gene and native American chestnut trees.

Pending approval by federal USDA, FDA, and EPA expected in 2021-22, TACF plans to cross the GE chestnut with hundreds of native American chestnuts maintained in gene-conservation orchards by the state chapters to produce highly diverse populations of chestnut for restoration plantings in coming decades. Blight-tolerant OxO chestnuts could be available for small-scale plantings by 2022 and for large-scale forest plantings in the 2030s. This would be first-ever use of GE for species restoration and is viewed by some as a model to help rescue other tree species threatened by invasive pests. It’s clear to me that GE use in many fields will increase in coming years and decades, and that our job should be to advocate for caution and evidence-based policy.

Eric is a longtime contact for Fedco and our liaison to regular updates on TACF ME Chapter’s activities, as well as access to seed for our nurseries. He has dedicated many years to restoring the American chestnut. He continues to monitor orchards across Maine and to present important questions, hopes and concerns about the chestnut’s future. His knowledge and dedication are an inspiration.

Fedco continues to support TACF’s traditional back-breeding program but will not offer GE chestnuts.

Dark Hort? More Questions than Answers.

by Jen Ries, Fedco Trees Coordinator, on behalf of Fedco

The chestnut, an iconic tree of the American landscape, is poised to become a different kind of icon of a new era. A petition has arrived at the USDA asking for the release of the genetically engineered Darling 58 chestnut tree with hopes of approval within the next year. If accepted, the genetically engineered (GE) chestnut would become the first GE tree used in a restoration planting. This is unprecedented. Once that box is open, it cannot be closed. Please consider taking some time to inform yourself.

Is it an act of restoration when what is being “restored” is altered in a way that would never occur in nature? Dr. William Powell, lead researcher of the engineered chestnut project, has presented this as a tree for the people. Is that true, or is this a tree for some people? Corporate lumber companies have sought approval to release GE trees into the landscape and have been met with public opposition. The GE chestnut could open this door to corporate interests. (“Know Your Farmers” is a good slogan to live by; so is “Know Your Funders!”) We have only the tiniest glimpse into how the intricate ancient relationships—evolved over millions of years—function among tree roots, fungi, insects and people, all of whom depend on the health of this dynamic system. We’re looking at potentially disrupting this forever. Are we ready for this?

The absence of information is alarming. The potential for mutations with unknown impacts is vast. In 1999, Cornell reported that the pollen of Bt corn (engineered to carry Bacillus thuringiensis) was found to be toxic to monarch butterflies. This impact had not been measured before the corn’s release. The pollen of GE trees will travel far and impart engineered genes to wild native trees. Will pest-resistant GE trees have a leg up on non-GE trees and lead to GE trees dominating the forest? GE lumber trees designed to produce less lignin could reduce costs and chemical inputs at the paper mill, but will the trees lack structural integrity, creating new problems and new genetic traits to be distributed into the forest? These are just hints at the concerns.

We want to right the wrongs of the past, but throwing incomplete science at the problems we’ve created has a sketchy track record. Remember when we were assured that PFAS sludge on our Maine fields was totally safe and would solve a recycling problem? DDT, Roundup-ready crops, fracking…“Better living through chemistry!” What could possibly go wrong?

Maybe GE is here to stay. If so, we must demand correct assessment, study and good policy implementation, as Eric stated in the previous column. Perhaps then we should be willing to put in 200–300 years to study the GE chestnut before we release it. In geologic time, this doesn’t seem like a tall order, considering the impact of this decision on our wild forests. Maybe it’s time to slow down, shift some patterns and reorganize our priorities. It’s time to consider the impact of the way we consume and move materials around the globe.

For decades now, Fedco has chimed in on the GE issue and how it threatens our environment and food systems. The GE chestnut is being presented for restoration, and perhaps considered not fundamentally linked to our food or seed systems. But we believe seed is seed, and food is food, whoever or whatever is eating it. This matters.

Fedco will not support GE trees. Furthermore, Fedco does not knowingly carry genetically engineered seeds. At our 1996 Annual Meeting, our cooperative voted unanimously not to knowingly offer for sale any genetically engineered variety because the new gene technologies pose unacceptable risks to the environment. For more about this pledge, our commitment to testing for GE contamination, and talks on GE by Fedco founder CR Lawn, please go here

You can find a short video and more info on why GE trees are a concern here and sign a petition here.

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