Blight has made the American chestnut, once "the dominant tree in the canopy," a rare sight in the forests of the East. Now some researchers hope to save the tree by giving it a last-ditch genetic modification, reports David Biello for Scientific American’s 60-Second Science podcast.
Scientists first noticed the fungal blight in 1904. It slides into the trees through wounds in the bark, grows, and eventually kills the tissue responsible for new growth. Researchers now suspect it came from Asian chestnut trees, which can resist the disease, explains Tamar Haspel for The Washington Post. She writes:
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.
Biello reports that such crossbreeding takes time as multiple generations need to pass before anything even approaching a full chestnut can grow. The gene modification approach is faster. But the source of the genes is somewhat surprising: they come from wheat. A single gene from wheat gives the chestnut the power to detoxify the acid the blight produces to destroy tree flesh.
A few of the hybrid chestnuts have been planted in the wild from New Jersey to Virginia. And test plots of the genetically foritified trees have shown promising results. Some environmentalists worry about genetically modified organisms. But a bit of genetic tweaking, whether by crossbreeding or gene insertion, looks like the only way to restore the chestnut to its former glory.
The American chestnut isn’t just an icon of a lost forest. Ferris Jabr, writing for Scientific American, emphasizes the tree’s importance as a source of food and shelter for animals and people. He writes:
Bears, deer and all manner of small mammals and birds feasted on fallen chestnuts, which sometimes piled so high on the forest floor that people would scoop them up with shovels. Reaching heights of 40 meters and growing two meters around the middle, American chestnuts were home to squirrels, chipmunks, blue jays and scores of benign burrowing insects. People, too, constructed their lives around chestnut. Lightweight, rot-resistant, straight-grained and easy to work with, chestnut wood was used to build houses, barns, telegraph poles, railroad ties, furniture and even musical instruments.
The newer effort would make the American chestnut a GMO. But Haspel argues in The Post that that shouldn't put people off. He says the effort is "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."