THEGREENGROK

GMOs and the American Chestnut: Risky Business?


by Bill Chameides | July 16th, 2013
posted by Erica Rowell (Editor)

Permalink | 17 comments
Researchers are working to develop a blight-resistant strain of the American chestnut, which has been all but wiped out. Seen here are Andy Newhouse (L) and Jason Corwin (R), at the American Chestnut Research and Restoration Project at SUNY, surface-sterilizing and extracting embryos from American chestnut burs in preparation for establishing them in Stage 1 medium. What if the best way to bring back this tree is via genetic engineering?
Researchers are working to develop a blight-resistant strain of the American chestnut, which has been all but wiped out. Seen here are Andy Newhouse (L) and Jason Corwin (R), at the American Chestnut Research and Restoration Project at SUNY, surface-sterilizing and extracting embryos from American chestnut burs in preparation for establishing them in Stage 1 medium. What if the best way to bring back this tree is via genetic engineering?

How far out on a limb would you go to bring back an icon of the American forest?

First, a Look at GMOs

Genetically modified organisms or GMOs can engender strong passions and stimulate spirited debate; at least they do in my family. Whenever we get together and the subject comes up, a lively discussion ensues, sometimes erupts, between my kids (well, kids to me even though they’re on the other side of 30) and me. To them, GMOs are plain bad.

The long-practiced art of artificial selection is one thing; but creating a transgenic organism by tinkering with its genetic makeup is, in their minds at least, something else entirely. Something that could unleash a vegetative (see here, here, here and here) or animalistic (see here, here, here, here and here) Frankenstein that could wreak havoc on the environment and possibly our food. Theirs is a sort of “Don’t mess with Mother Nature” imperative.

Besides, they continue, look what the Big Ag companies are doing with GMO technology. Producing strains of crops that allow farmers to use huge quantities of pesticides that poison the environment (see video) and our food and in the end only speed the evolution of pesticide-resistant superweeds (see here, here, here and here) and pests. (They can also turn the small farmer and the subsistence farmer into farmers with a bunch of dead crops, as this film about Peruvian farmers documents.)

To me, the issue is not so black and white. We have been genetically engineering crops for millennia, albeit not using modern molecular biology but by crossbreeding and artificial selection. The methods may be different, but the result is much the same: an organism whose genetic makeup has been altered by humans to suit human needs.

Is there any difference between an organism that has been designed through the time-honored hybridization method and one designed using modern molecular biology? I don’t think so. Genetic engineering gives biologists a much larger tool chest of genetic material to operate with but in the final analysis an organism is determined by its genetic makeup not how that makeup was constructed.

And as far as the Big Ag stuff goes: just because some companies use GMO technology to bad ends does not mean the technology is a priori bad.

The debate eventually ends because of exhaustion and without any resolution, let alone a meeting of the minds. I’ve often wondered if our inability to find common ground on GMOs is that my anti-GMO offspring are conflating GMOs with their perceived evils of Big Ag and their concerns for our sustainable foods. Wouldn’t it be great if there were an issue that purely focused on the benefits and risks of GMOs alone? Well, I think I’ve found one: efforts to bring back the American chestnut tree.

Remember the American Chestnut?

The American chestnut was once one of the country's great trees

The American chestnut was once one of the country’s great trees. (Forest Historical Society)

There was a time when the American chestnut tree “reigned over 200 million acres of eastern woodlands from Maine to Florida, and from the Piedmont west to the Ohio Valley. … An estimated 4 billion American chestnuts, 1/4 of the hardwood tree population, grew within this range.” See range map. (Remember “Under a spreading chestnut-tree/The village smithy stands” from 1840?)

These were magnificent trees —150 feet tall — with a bountiful crop of chestnuts that supported wildlife and provided wood timber ideally suited for items ranging from fence posts to musical instruments (which reminds me of another ode to the chestnut circa the 1950s: “perfect/as a violin that has just/been born in the treetops/and falls/offering the gifts locked inside it,/its hidden sweetness”).

But in the 20th century all the grandeur and natural poetry of this once mighty tree changed. A fungus imported with the Asian chestnut (called chestnut blight or Cryphonectria parasitica) virtually wiped out mature American chestnuts from the American landscape by the 1950s. (See here [pdf] for fuller history.)

Seedling American chestnut trees still appear in the forest, but “survive primarily as stump sprouts and small understory trees, which are often killed back to the ground (by the blight) before flowering” and generating chestnuts. Sources here [pdf] and here. (For more on the American chestnut see here, here and here.)

Two Efforts to Bring the Chestnut Back

Fortunately, a comeback may be in the works for the American chestnut. There are now at least two groups working to develop a blight-resistant strain of the American chestnut that can be reintroduced into the forests of the eastern United States with a chance of survival.* (Whether such blight-resistant trees will propagate is uncertain as much of the niche once occupied by the American chestnut is now filled by oaks.)

The American Chestnut Foundation, supported by the U.S. Forest Service, is working to bring back the American chestnut through a process called the backcross method. Pictured is a planting site. (U.S. Forest Service)

The American Chestnut Foundation, supported by the U.S. Forest Service, is working to bring back the American chestnut through a process called the backcross method. Pictured here is a planting site. (U.S. Forest Service)

The American Chestnut Foundation is pursuing a traditional hybridization approach. They begin by crossbreeding an American chestnut with a Chinese chestnut, identify those that are most resistant to blight, and continue to crossbreed with American chestnuts and selecting for blight resistance.

The group has now developed a new strain of chestnut that is genetically 15/16ths American chestnut and 1/16th Chinese chestnut, with that last 1/16th hopefully carrying the Chinese chestnuts’ blight-resistant genes. (For more details on this work see my earlier post and this Americanforests.org article.) The American Chestnut Foundation has a crop of these 15/16ths American chestnuts and has begun planting them in the wild. Will they make it? We’ll have to wait and see.

The other group, at the College of Environmental Science and Forestry of the State University of New York in Syracuse, is using molecular biology. In the American Chestnut Research and Restoration Project, scientists are attempting to produce a genetically modified, transgenic strain of American chestnut that is resistant to the Chinese blight. To do so, as Helen Thompson reports in the journal Nature, they have taken genes “from Chinese chestnuts as well as plants such as wheat, peppers and grapes” and inserted them into the genetic sequence of an American chestnut.

The group has now planted some 600 of the genetically modified trees in field trials and a variety with a gene from wheat is showing signs of blight resistance. As the New York Times reports, because the trees from the American Chestnut Research and Restoration Project are transgenic, they “can be raised only in orchards and other places where there is no potential for their pollen to fertilize other trees.” Presumably a variety of regulatory hurdles would need to be cleared before these trees could planted in the wild. (See here [pdf] and here.)

So there you have it, two groups with noble intentions aimed at restoring a majestic tree — one using traditional methods and the other genetic engineering. Is the traditional method better? Is the GMO approach wrong? What if the traditional method doesn’t work and genetic engineering ends up being our only option for bringing back the American chestnut? Should we forgo the possibility of bringing back the American chestnut tree because of a fear that genetic engineering could produce a tree Frankenstein?

I asked one of my kids that. He thought a moment and said, “A GMO version of the American chestnut? Risky.” I was going to push him on this, but then I thought of all the times in his youth when I had admonished him to “be safe.” Maybe a little caution wouldn’t be such a bad thing.

____________

End Note

* Other researchers are taking a completely different tack, developing viruses that attack the Chinese blight fungus itself. If successful, such viruses could be injected into infected trees to save them. One such researcher is Don Nuss at the University of Maryland in College Park who is using a genetically modified fungus to carry the virus into the tree. A project in New Jersey [pdf] is taking “chestnuts from trees that have demonstrated resistance to blight and has these seeds grown to seedlings at Bayside State Prison through a cooperative program.  The seedlings are then provided to landowners with appropriate planting areas to promote restoration.”

A planting project by the American Chestnut Foundation aimed at restoring the American chestnut tree.

A planting project by the American Chestnut Foundation aimed at restoring the American chestnut tree.

Post updated on 7/19/2013, 5:15 PM:
The post was updated to remove the picture of a diseased elm tree mislabeled as an American chestnut tree.

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17 Comments

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  1. Paul Sutera
    Aug 25, 2013

    The American Chestnut may not bear offspring with the wheat gene intact. But if it does, the new Chestnut would spread very quickly. This is a tree that can grow in the shade until nearby trees die. It’s an incredibly prolific tree, so this new GMO tree could really spread. This is a tree that can establish itself as a monoculture in suitable areas. The plus side is that Chestnuts can feed rural populations in times of food-shortages. The trees produce large quantities of nuts every year, and always flower after the frost, in June.

  2. Hank Roberts
    Jul 28, 2013

    Is this doing it right? Dunno, but it’s another plant to consider, with apt comparisons:
    http://www.nytimes.com/gwire/2011/09/21/21greenwire-crop-savior-blazes-biotech-trail-but-few-scien-88379.html

  3. Greg Shideler
    Jul 27, 2013

    ‘Fraid I side with your children Bill.
Given our current knowledge, GMO poses inherent risk and if ever the Precautionary Principle needs to be applied, it is with genetic engineering.
First hybridizing is not the same! My main problem with GMO’s is that it is all based on Mendel’s work and assumes one gene expresses one phenotype and is not influenced by other genes. This is wrong. I think David Suzuki still holds the record @ about 230 phenotypes for the fruit fly gene. We also know that replacing or misplacing the gene sequence causes uncertainty in organisms, and indeed the organism will attempt to correct the gene pattern.
Not to mention Antibiotic Resistant Markers, viral or gene gun insertion, and a whole host of techniques with build in problems.
The science tells us everyday, we do not understand genetics well enough to let the cat of the bag! Take a look at the work of Elaine Ingham @ Oregon State University with the safety of Klebsiella planticola a “beneficial soil micro-organism” about to be commercialized and how it almost destroyed plant life. http://online.sfsu.edu/rone/GEessays/Klebsiellaplanticola.html
The most important lesson is that we need the highest standards (Precautionary Principle) of safety in regards to releasing GMO’s.
    Bill, maybe the kids are right, Greg

    • Hank Roberts
      Jul 28, 2013

      > http://online.sfsu.edu/rone/GEessays/Klebsiellaplanticola.html

      Greengrok administrators, would you follow up on that?

      First I’ve heard of it, but Dr. Ingham’s lab has been doing good work for a long while; I sent soil samples there when I first started doing forest fire restoration decades ago (and found how slowly the microbiology recovered on old logging roads compared to a few yards away on relatively undisturbed areas, which changed how we did some of the restoration planting).

      The linked essay deserves GreenGrok followup. Please.

    • Paul Sutera
      Aug 25, 2013

      My understanding is that the wheat gene is inserted to change the way the Chestnut deals with Oxalic acid. Oxalic acid is produced by the fungus and quickly girdles the American Chestnut in about a year. The interesting thing about the fungus is its own lack of genetic diversity. North American Chestnuts may have evolved to favor height and fast growth that left wound healing in the usually fungus resistant tree as a less-selected trait. The Butternut is facing a similar problem today.

  4. Dave Burton
    Jul 20, 2013

    Hank Roberts wrote on JUL 19, 2013
    >> I presume
    > that’s why I didn’t presume. The scientists know better. Listen to them..

    Actually you presume a lot, and you didn’t answer either question. I wrote:

    I’d love to be wrong, but it’s my understanding that it’s rare for those shoots to produce nuts. I presume that’s why the Chestnut shoots found in the Chestnut tree’s old range are uniformly described as growing from old root stock, not from nuts.

    Why do you think that is? Maybe they occasionally bloom, but because they need to be pollinated from other blooming chestnuts, the blooms don’t produce nuts.

    Or, perhaps some shoots do produce nuts that sprout and grow, but that those seedlings don’t make it to the next generation to produce nuts of their own, because their root systems are too small to survive when the sapling is killed off by the blight.

    One way or another, it seems that there’s essentially zero chance of GMO pollen “contaminating” the existing American Chestnut gene pool, because, with the exception of rare trees outside the Chestnut’s normal range, American Chestnuts can no longer reproduce. Do you disagree?

    Changing topics… while the American Chestnut Research and Restoration Project is improving American Chestnuts to withstand the blight, I’d like to see them also improve it by breeding a chestnut variant with no spines on its burs. That would make it much more desirable as a shade tree, and help encourage widespread planting.

    So, Hank, do you agree with me that “with the exception of rare trees outside the Chestnut’s normal range, American Chestnuts can no longer reproduce,” and that therefore there’s no risk of GMO pollen “contaminating” the existing American Chestnut gene pool?

    If Chestnut shoots could reproduce in the presence of blight, we could hope that eventually they would breed a resistant strain on their own. But I’ve never heard of any scientist who thought that could happen. Have you?

    • Hank Roberts
      Jul 28, 2013

      You don’t know, and the scientists doing the work, who do have estimates, haven’t been invited to comment.

      The PR push continues:

      http://www.nytimes.com/2013/07/28/science/a-race-to-save-the-orange-by-altering-its-dna.html

      Oh, you’re not sure about saving chestnuts?
      Well, how do you feel about saving oranges?

      Next up, bananas, and then Tasmanian Devils

      Surely there’s an argument the public will accept to legalize genetic engineering wholesale.

      Then Monsanto can go back to producing agricultural products that die unless sprayed with their supplements, or whatever their business plan is.

      Dave, whatever you’re campaigning about, I don’t play the game of asking unqualified people to make estimates of probability to decide basic policy decisions.

      My take is — genetic engineering isn’t the issue.
      It’s a strawman argument being put up to try to legitimize what Monsanto has been doing, which is stupid.

      It’s not the tool, it’s what you do with it. Roundup-ready crops was a stupid, cheap, shortsighted, way to make money fast. Resistance to disease isn’t simple either.

      Monsanto bought temporary immunity in this last legislative session, for this growing season: https://en.wikipedia.org/wiki/Farmer_Assurance_Provision

      Now they’re ramping up the PR work.

      Are you ready for, oh, how about gene-engineered “safe tobacco” products to be sold to your kids? Just you wait and see what else can be done if there’s no constraint on _results_ they can claim to have attained and sell (whether they’re real or not)

  5. Hank Roberts
    Jul 19, 2013

    The new formatting of the blog kills dialog after a few comments.

    A plea — ask one of the scientists involved to respond to the opinions Dave is proclaiming above? He’s a prolific commenter on many websites related to climate change, and he’s doing his usual thing.

    Getting the scientists doing the work to comment may further discussion.

  6. Hank Roberts
    Jul 18, 2013

    I hope one of the scientists involved will speak up here.

    Looks to me like interfering with oxalic acid metabolism, as the gene mod approach hopes to do, can go either way (and it may change as the plant ages):

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2634576/ Toxic and signalling effects of oxalic acid
    Oxalic acid–Natural born killer or natural born protector?

  7. Dave Burton
    Jul 17, 2013

    You’re right, your kids are wrong. Genes get transferred between species all the time in nature, via viruses, agrobacterium, et cetera. Both GMO technology and traditional breeding can be used to breed either good or bad organisms… or both.

    And besides: what, exactly, could the pollen from a GMO American Chestnut “contaminate,” anyhow? Nothing but Chinese Chestnuts, since all the American Chestnuts are dead.

    • Hank Roberts
      Jul 17, 2013

      My first comment’s still lost in moderation, apparently — look at badgersett.com — and that would have disabused Dave Burton of his misapprehension.

      Dave, the American chestnuts are still alive in many places — some as mature trees because they’re outside the range of the blight, others as stumps still sprouting and putting up leaves and shoots that last for a few years before the blight knocks them back. The root systems are still there and alive in those trees.

      The fellow at Badgersett is an old college friend, I’ve written about his early work years ago — he went out and collected native stock from all over, planted trees, grew them up a few years, killed off most of them, planted new ones — selecting the way farmers have done for thousands of year, but doing it with a database and criteria that he tracked to select for a variety of useful traits including blight resistance.

      You should look this stuff up.

      Particularly, before you go telling people bad information, just ‘oogle what you believe.

      “It’s a poor memory that only works backwards.” Check yours against what’s currently available.

      • Dave Burton
        Jul 17, 2013

        Hank, it is VERY cool what your friend does, but on his web site he says his Chestnuts are hybrids, not pure American Chestnuts. His project is probably similar to what The American Chestnut Foundation is doing, though he doesn’t say what percentage of his hybrid’s genome is actually American Chestnut.

        Unfortunately, all the American Chestnut trees that could be “contaminated” from GMO Chestnuts are, indeed, dead and gone. There are are some stumps that periodically put up living shoots but never produce nuts (so GMO pollen can’t affect them), and there are a few isolated specimens in places where American Chestnuts weren’t normally found (so GMO trees wouldn’t be planted there, either), and that’s it. Literally 99.999% of the American Chestnut trees are dead and gone, and anywhere GMO trees would be planted it’s 100.000%. If a surviving tree is so isolated from the normal American Chestnut tree range that the Chestnut Blight fungus has never reached it, then neither will GMO pollen.

        • Hank Roberts
          Jul 18, 2013

          Look it up for yourself. You’ll find what you’re certain of isn’t true.

          ” … Sprouts emerge from American chestnut stumps, live maybe eight to 15 years, get the blight and die, sometimes producing nuts in the process….”

          http://www.post-gazette.com/stories/sectionfront/life/can-the-american-chestnut-tree-be-revived-222443/

          That’s just one of many examples easily found to check your claim.

          You know why science articles cite sources: because you’re entitled to your own opinion.

          • Dave Burton
            Jul 18, 2013

            I’d love to be wrong, but it’s my understanding that it’s rare for those shoots to produce nuts. I presume that’s why the Chestnut shoots found in the Chestnut tree’s old range are uniformly described as growing from old root stock, not from nuts.

            Why do you think that is? Maybe they occasionally bloom, but because they need to be pollinated from other blooming chestnuts, the blooms don’t produce nuts.

            Or, perhaps some shoots do produce nuts that sprout and grow, but that those seedlings don’t make it to the next generation to produce nuts of their own, because their root systems are too small to survive when the sapling is killed off by the blight.

            One way or another, it seems that there’s essentially zero chance of GMO pollen “contaminating” the existing American Chestnut gene pool, because, with the exception of rare trees outside the Chestnut’s normal range, American Chestnuts can no longer reproduce. Do you disagree?

            Changing topics… while the American Chestnut Research and Restoration Project is improving American Chestnuts to withstand the blight, I’d like to see them also improve it by breeding a chestnut variant with no spines on its burs. That would make it much more desirable as a shade tree, and help encourage widespread planting.

            • Hank Roberts
              Jul 19, 2013

              > I presume
              > that’s why

              I didn’t presume. The scientists know better. Listen to them..

  8. Hank Roberts
    Jul 16, 2013

    Three: Badgersett.com

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