Nearly 60 million acres of American forests are experiencing mortality rates far outside historical norms. This is due to increased outbreaks of endemic and exotic pests, which are up three-fold in just 10 years. The number of insects, pests, and diseases being unleashed on forests threatens to overwhelm the system. Currently, responses to these 21st Century challenges are mostly limited to 19th and 20th Century technologies. The Advancing Forest Health through Biotechnology (a.k.a. “Forest Health Initiative” ) program advances the scientific use of biotechnology to address forest health challenges, while also considering regulatory issues and the need for better societal awareness and understanding of the concept.
An ambitious program to use genetic engineering techniques to develop a disease- and blight resistant American chestnut was chosen as the pilot project for this program. The American chestnut was chosen due to the availability of data on blight resistance and breeding stock. It also provides an opportunity for regulatory agencies to review a biotech tree intended for social benefit. A close relative, the Chinese chestnut, provided disease- and blight-resistant genes.
Phase I accomplishments include:
Sequencing the Chinese chestnut genome;
Inserting blight resistant genes from Chinese chestnut into the American chestnut; and
Developing early disease screening (at six months) as opposed to the current “plant and wait” strategy, which takes 4-6 years.
Phase II is underway and includes:
Field testing for resistance in plantings;
Review of potential environmental concerns related to field -testing; and,
Assessment of public attitudes and messaging to support use of biotechnology to address forest health.
A “braided” approach is being used to address the three key challenges associated with a genetically-modified American chestnut:
Social & Environmental
FHI engages the Department of Agriculture, the Environmental Protection Agency, and the Food and Drug Administration – agencies with jurisdiction over a biotech American chestnut- challenging each to consider how biotechnology might be used to improve forest health.
FHI is supporting work to revive the American chestnut with a transgenic variety modified with genes from the related Chinese chestnut, which is blight resistant. This surgical approach to traditional breeding incorporates only the few resistant genes needed to effectively inoculate the American chestnut against the blight.
FHI works with more than 35 stakeholders to gain their input and views about the potential of biotechnology as a tool for forest health, and on developing guidance for using biotechnology in environmentally responsibly ways.
In October 2008 the first phase of this project to develop a disease-resistant American chestnut (Castanea dentatea) began. The American chestnut was chosen as a test case because it had been a valuable landscape tree as well as a crop tree for edible nuts and wood products, until being devastated by two introduced diseases. With funding from the USDA Forest Service and Duke Energy, the Endowment distributed funds to several universities and research institutions to fund research. Through this research, advances have been made on all fronts of the science component of this project. Highlights include:
Production of the first “proof-of-concept” plantable transgenic (genetically engineered) trees with blight resistance that equals or exceeds the resistance in Chinese chestnut (Castanea mollissima).
Developing gene insertion and plant multiplication processes that can quickly produce transgenic trees for testing resistance induced by a variety of genes.
Cloning of 27 chestnut candidate genes and 6 genes from other plants that have potential to enhance resistance to blight, or alternatively to root rot, a serious additional threat to chestnut.
Sequencing of the Chinese chestnut genome, a major advance that allows the use of genomic tools for faster research, breeding, and selection for resistance.
In addition to the scientific advances in this initiative, there have been several developments in the policy and social components.
Phase II builds on the many successes of Phase I. To obtain healthy, stably resistant varieties for restoration, the protocols and genes identified in Phase I must be developed further, and many additional resistant transgenic and non-transgenic trees need to be field-tested. Phase II incorporates both non-transgenic and transgenic research to bring the broadest approach possible to American chestnut review (and by extension benefits to other trees):
Testing the validity of transgenic tree resistance s in field tests at multiple locations representing sites targeted for restoration;
Developing and testing new resistance genes, which have been carefully selected to include multiple independent resistance mechanisms, thus providing durable, multiple-gene based resistance against chestnut blight;
Evaluating the utility of clonal (non-transgenic) testing and marker-assisted selection as a complement to a transgenic approach. A genomic selection trial is now possible that would speed identification of the most highly resistant genotypes for next generation testing. It would also help to identify additional resistance genes for other transgenic or breeding applications.
Phase II of this project supports social science research to determine the extent and conditions under which the public might support various biotechnologies in battling threats to forest health. This research will address:
Public perception of the significance of threats from new pests and climate stresses to forests,
The desirability of various biotechnologies as tools to help address these threats, and
Context for background and language that will provide help to the public to understand, and provide opinions, about the use of biotechnologies to help improve forest health.
Regulatory and Policy. As field trials of transgenic American chestnut trees are planted during Phase 2, the highest standards of compliance and stewardship of biotech trees will be followed, including the Responsible Use Principles for Biotech Trees. Discussion with the three principle regulatory agencies, USDA APHIS, EPA and FDA, will continue to investigate both public interest products and cisgenic (chestnut to chestnut) approaches.