American Chestnut: Blight and the Resurrection of a Mighty Giant

Abstract

The chestnut blight fungus, Cryphonectria parasitica, is a canker pathogen capable of colonizing wounds created by self-pruning, winter injury, insects, woodland mammals, and mechanical injuries that expose the inner bark. Within 50 years of the initial discovery, nearly 8.5 million acres of chestnut forests had fallen prey to the pathogen. The devastation incited by “the blight” was, and remains to this day, one of the greatest single transformative events ever recorded in a natural plant population. With recent advances in molecular biotechnology, the opportunity to restore American chestnut via genetic modification is within grasp. Transformation research in chestnut has evolved rapidly over the last decade, focusing on the development of traditional transgenic methods to introduce pest resistance genes found in model pathosytems?-?such as the oxalate oxidase gene found in wheat?-?into chestnut as a means to counteract the chemical arsenal employed by the chestnut blight fungus.