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Chestnut Lovers - Remember Biotech Over Holidays!

December 2, 2014
In the early 1900s, the eastern United States chestnut tree population was hit with a pathogenic fungus called Cryphonectria parasitica.  This fungus is the main cause of chestnut blight, a disease that wiped out 3 to 4 billion trees in just a couple of decades and nearly devastated the entire chestnut tree population.  The chestnut blight was first spotted in 1904 and is believed to have arrived here in Asian chestnut trees. Unfortunately, American chestnuts have no resistance to the fungus, making it all too susceptible to the disease.

As part of her Unearthed Series, Washington Post columnist Tamar Haspel wrote a great piece highlighting how genetic modification has helped bring bring back the American chestnut population.  In her post, Haspel reminds readers the role that the chestnut has played in American history:
"It was nearly 400 years ago that the Pilgrims sat down with the Wampanoag to share the feast that is immortalized as Thanksgiving. We don’t know the exact menu. According to Kathleen Wall, foodways culinarian at Plimoth Plantation, venison, fowl and corn were documented by attendees, but, beyond that, we can only speculate. I asked if we could speculate about chestnuts.

"'We can’t say for sure, but the odds are pretty good,' she says. 'They’re right in season. Both cultures knew them and used them.'

"Susan Freinkel, in her excellent book 'American Chestnut: The Life, Death, and Rebirth of a Perfect Tree,' describes how, in the fall, when the nuts were sometimes inches deep on the ground, families used to gather them for their own use and to sell. Livestock was let loose to eat their fill. People who didn’t eat chestnuts often ate chestnut-fed venison or squirrel. Furniture, fence posts and utility poles were made of the long, straight, rot-resistant timber. In some places, one in four forest trees was a chestnut, and the tallest stood 12 stories high."

Then the chestnut population was hit with the fungus, nearly killing all of them.  So, what did it mean to lose 3 to 4 billion trees:
"It’s hard to get your arms around a number that big, so let’s convert it to something useful: food. A mature tree can produce several hundred pounds of nuts (the record is more than 1,000 pounds); about 70 percent of that weight is actual nutmeat. For the sake of being conservative and working with round numbers, let’s call it 100 pounds of nutmeat per tree, at about 1,000 calories per pound, or 100,000 calories per tree. So 10 trees would provide the million calories (give or take) one person eats in a year.

"Here’s what that means: If we still had those 3 to 4 billion trees, they would meet 100 percent of the caloric needs of today’s entire American population of just over 300 million. They could feed every last one of us.

"Of course, even without the blight, we’d have lost a good portion of the trees as development encroached on forests. And living exclusively on chestnuts would get old fast, anyhow, despite their versatility as a foodstuff: They can be roasted, fried, candied, steamed, grilled and even turned into flour. Those numbers are just a way to imagine how significant a food source American chestnut trees were, and could be again."

Here enters biotechnology.  Haspel explains how improved farming technology provides us with a readily available supply of  high-quality, good tasting food:
"Thanks to a group of scientists at the State University of New York College of Environmental Science and Forestry, headed by Bill Powell and Chuck Maynard...On Nov. 4, they announced that they had bred a blight-resistant American chestnut by introducing a gene from wheat.

"Blight kills trees by producing oxalic acid. Wheat has a natural defense against oxalic acid; the plant can break it down into benign components. It turns out that a single gene is responsible for that function, and inserting that single gene into the American chestnut genome made the tree resistant.

"Over the past year, I’ve written quite a bit in this column about genetically modified organisms (GMOs), and I’m going to put that issue on the shelf for a while. But I couldn’t do it without mentioning the blight-resistant American chestnut, because it’s everything that the GMOs now in our food supply are not. It wasn’t created for personal profit or for the benefit of corporations or farmers. It contributes to a wholesome, healthful diet. And it’s intended solely for the public good"

There has been an effort — ongoing in the 100 years since the blight — to create blight-resistant American chestnuts by cross-breeding with Chinese chestnuts, and the American Chestnut Foundation has had some success on that front, but it hasn’t yet achieved its goal. "Powell told me he’s glad others are taking a different approach, because having the trees from both programs out there in the forest would increase the genetic diversity and the chance that American chestnuts will thrive. "