Fourth Annual Long Island Natural History Conference




















American Chestnut: Leading the Way to a Healthier Forest

William Powell, SUNY College of Environmental Science & Forestry, Syracuse, NY.

The American chestnut (Castanea dentata) and chestnut blight is the classic example of what happens when our forests succumb to exotic pests and pathogens. Because of its environmental, economic, and social importance, many tools have been brought to bear on the chestnut blight problem. We have focused on enhancing blight resistance by adding only a couple of genes to the approximately 40,000 gene pairs in the chestnut genome using the tools of genetic engineering. The most promising gene to date encodes an oxalate-detoxifying enzyme, called oxalate oxidase (OxO). This gene comes from bread wheat (Triticum aestivum), but is also a common defense gene found in many plants including all grain crops as well as bananas, strawberries, peanut, and other familiar produce.

The OxO is not a pesticide, not an allergen, and is not a gluten protein. According to chestnut leaf and small stem assays that predict the level of blight resistance, this OxO has raised resistance levels in American chestnut at least as high as those found in the blight-resistant Chinese chestnut (C. mollissima). This will be the first time an ecosystem restoration program will use the tools of genetic engineering.  The next step is to have the trees reviewed by three federal regulatory agencies, the USDA, EPA, and FDA. Once approved, these blight-resistant American chestnut trees can be used to rescue the genetic diversity in the remnant, surviving population of American chestnut and be an additional tool for the restoration of this important keystone tree.

Dr. William A. Powell received his BS in biology in 1982 at Salisbury University, MD, and his PhD in 1986 at Utah State University studying the molecular mechanisms of hypovirulence in the chestnut blight fungus, Cryphonectria parasitica. He spent over two years as a postdoctoral associate at University of Florida researching transformation techniques using the fungal pathogen, Fusarium oxysporum. In 1989 he became a faculty member at the State University of New York’s College of Environmental Science and Forestry at Syracuse, NY, where he began collaborating with his colleague, Dr. Charles Maynard, researching methods to develop a blight-resistant American chestnut (Castanea dentata) tree.  He has also worked with American elm and hybrid poplar. Dr. Powell currently has over 50 peer-reviewed publications and one patent. He teaches courses in Principles of Genetics, Plant Biotechnology, and Biotechnology Freshman orientation. His most significant accomplishment, with Dr. Maynard, is the enhancement of blight resistance in American chestnut by his research team and collaborators. Email: