Bringing Back the American Chestnut

July 1996

Greensboro, NC: At the turn of the century, American chestnut trees filled mountainous regions from Maine to Florida. Growing to heights of nearly 100 feet, their presence commanded attention and inspired respect. At that time, it w as nearly impossible for a traveller in the region not to find themselves in awe of the majestic trees.

Disease changed all of that. In 1904, a fungus was discovered growing on American chestnut trees in New York City. A disease more destructive than the infamous Dutch elm disease, the fungus spread rapidly, 20 to 50 miles each year, killing virtual ly every tree it encountered. By 1950, American chestnut trees had essentially disappeared from our forests. Americans had lost not only a beautiful part of their landscape, but a valuable source of wood and nuts.

Currently, since the fungus affects primarily the main stems of the plant, the root system often survives. Trees frequently sprout from these roots before being cut down by the disease. On Mount Pisgah, in North Carolina's Blue Ridge Mountains, Amer ican chestnut trees grow to 20 feet and occasionally produce nuts.

Still, this valuable natural resource remains a mere shadow of its former self. For that reason, committed scientists are researching ways to return the tree to the grandeur that it once held. One of those scientists is Dr. Guochen Yang, a plant bi otechnologist with the North Carolina A&T State University School of Agriculture.

"The American chestnut tree is particularly interesting due to its history," said Yang. "Because it was once held in such high regard, people are anxious for its return."

To effect this return, Yang is using biotechnology to develop plants that are resistant to the disease. The first step in this process is establishing a protocol for developing genetically altered shoots. From this protocol, called direct organogen esis, Yang is able to produce as many as 40 shoots from a single plant.

"Direct organogenesis is a must for genetic transformation," said Yang. "This process allows a scientist to quickly produce and test the plants he produces."

As Yang uses direct organogenesis to produce plants, he alters the genetic composition in an effort to produce a plant that is resistant to the fungus that stifles the growth of an otherwise prolific tree.

"This type of work has implications beyond the chestnut tree," said Yang. "Our success with genetic transformation techniques can help others in similar research."

To illustrate his point, Yang refers to other scientists presently researching ways of making other plants disease- and pest-resistant. If such research were successful, the need for harmful chemicals would be eliminated, thereby preserving our environment.

- 30 -

For more information, please contact Dr. Guochen Yang, North Carolina A&T State University School of Agriculture, (336) 334-7259.