New roots
The American chestnut tree could make a comeback with the help of biotechnology and the American Chestnut Research and Restoration Center.
The center is based at the State University of New York College of Environmental Science and Forestry in Bray Hall and aims to restore the chestnut tree to New York and, eventually, the United States.
Once a staple in forest ecosystems, the American chestnut tree was virtually eliminated by the chestnut-blight fungus by 1940. The blight was introduced in the early 1900s by Asian chestnut trees brought to New York as orchard trees, and has killed more than four billion trees.
The blight produces an acid, which is also found in deck cleaner. The acid kills the trees by lowering the wood’s pH, which causes cell walls to collapse and destroys protein.
The center is using biotechnology to splice different kinds of plant genes into American chestnut trees to make them resistant to the fungus, said Bill Powell, a co-director of the American Chestnut Research and Restoration Center.
‘We’re trying to find one, two or three genes that we can put into the tree to make it resistant and then use that for restoration,’ Powell said.
Research on the chestnut tree started at ESF in the 1980s, but the center was officially created in the late 1990s.
The chestnut tree was once a valuable part of the environment. Animals depended on chestnuts to fatten up before winter, and when the trees died many animal populations decreased. ‘If we bring them back, it might allow areas to support larger numbers of wildlife,’ Powell said.
The chestnut tree was also an important part of America’s architecture industry. Chestnut wood is durable and doesn’t have to be pressure treated to prevent rot. Because of its rot resistance, chestnut wood was used in shingles, train tracks, telephone poles and house building, said Charles Maynard, co-director of the American Chestnut Research and Restoration Center and a professor of forest and natural resources management at ESF.
Once they identify a usable gene, scientists will place the genes into specific types of plant tissue that are able to regenerate a whole plant, Maynard said.
Using a gene to regenerate a whole plant is not an easy process, Powell said.
‘Most of the two decades that we’ve been working on this has been development of a regeneration technique where you can basically regenerate a whole plant from a single cell,’ he said.
The process of going from gene splicing to a full-grown plant can take 18 to 20 months. The 12-step process has been designed to take less time through a system called pipelining, which allows researchers to splice several genes at one time rather than waiting 18 months for each gene to grow into a tree.
In the past, scientists only tested one gene at a time. Now, they can test several at the same time, Powell said. ‘We’re kind of overlapping things so that every few months we can get a different gene out to test,’ he said.
The process will soon be a lot easier. Research supported by the Forest Health Initiative grant is being done to sequence the chestnut genome, which will allow blight-resistant genes in Asian chestnut trees to be isolated. Once the genes are identified, they can be moved directly to the American chestnut trees.
Until the chestnut genome is sequenced, genes from other plants are being used.
‘Our favorite one right now is one that comes from wheat. The neat thing about that gene is that it doesn’t attack the (fungus) directly. It disarms the fungus,’ Powell said.
The enzyme in the wheat gene breaks down the destructive acid, making it harmless to the tree, Powell said. The first fungus-resistant trees produced at ESF’s center contain the wheat gene.
It will take a few years before the genetically altered trees’ resistance can be seen. The blight doesn’t target saplings, so researchers would need to wait for the tree to mature in order to find if it established a resistance, Maynard said.
Because the restoration process is made up of continual research, there is no finish line currently in sight, Powell said.
‘For the past 20 years, we’ve been saying five years. It’s hard to predict. It’s research, you don’t know how long it’s going to take for sure,’ Powell said.
Published on November 4, 2009 at 12:00 pm
