Impact/Purpose:

The objective of this task is to develop genetic methodologies for evaluating and decreasing ecological risks posed by genetically modified crops (GPRA goal 4.5.2). This research has the following primary aims:

measurement of population genetic parameters for target pest populations in order to inform pest resistance management models genetic analysis of resistance/tolerance to Bt-toxin in laboratory pest strains to investigate the genetic basis of Bt resistance development of molecular genetic indicators of exposure of nontarget organisms to Bt toxins development and evaluation of a genetic monitoring program for establishing population trends and probable impacts for non-target populations near GM-crop fields.

Description:

This research effort is designed to provide the risk assessment community with modern genetic tools for evaluating long-term risks of genetically modified (GM) crops. Molecular population genetic data can potentially reveal information about long-term trends in both pest populations targeted by plant-incorporated pesticides (PIPs) and non-target populations. EPA regulations require specific pest management strategies to slow the evolution of resistance in target pest populations in order to prolong the environmental benefits of GM crops (i.e., reduced use of chemical pesticides). A key component of this research effort will be to provide detailed information on pest biology, including gene flow and mating patterns in the wild (within species and between closely related species), geographic and chromosomal distribution of resistance alleles, and the additive and non-additive effects of genetic variation on resistance under selective pressures in the field. These data will be used to improve and validate models of insect resistance development with the goal of implementing best agricultural practices for delaying or preventing the development of pest resistance. These methods will be evaluated as a necessary component in the process of developing novel PIPs.

In comparison to pest populations, the exposure of non-target populations to toxins from GM crops like Bt-corn (i.e. corn expressing an insecticidal protein derived from the bacterium Bacillus thuringiensis) and the long term population-level effects of these exposures are very poorly understood. Short-term field studies have failed to detect significant population effects on non-targets. However, sensitive methods to evaluate the exposures of non-targets to GM crops and long term population effects are lacking. Genetic methods we have developed for aquatic indicator species can be adapted to the assessment of non-target insect populations in order to provide baseline population data and a cost-effective methodology for monitoring long-term population trends. These methods will be evaluated as a routine monitoring tool for the assessment of GM crop safety on non-target species. Together with the research on pest populations, the monitoring of non-targets will be used to determine the current and future safety of GM crops.

An important aspect of this biotechnology research effort is that it focuses on the comparison of GM crops to traditional farming practices. To effectively compare the risks and benefits of GM crops, they must be evaluated relative to realistic alternatives, which includes the effects of traditional industrial scale farming and its concomitant use of pesticides. Planned research will begin to assess the effects of traditional pesticides (i.e. organophosphates, carbamates, etc.) on non-target communities and compare them to the effects of GM crop use. One of the rationales for the approval of GM crops such as Bt corn and cotton is that they are predicted to reduce the use of traditional chemical pesticides which, if true, would represent an ecosystem benefit. Planned non-target studies will compare the effects of traditional agricultural practices, such as chemical pesticide use, to novel GM crop practices in terms of impacts to the long-term sustainability of non-target organisms. This effort will focus on threatened and endangered insects including aquatic non-targets. Pesticide run-off into streams and rivers is an important environmental issue and we will address this issue by comparing the use of GM crops to the use of traditional chemical pesticides on our nation's streams and rivers.

Record Details:

Record Type:PROJECT

Start Date:10/01/2003

Projected Completion Date:09/30/2008

OMB Category:Other

Record ID: 81024

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Project Information:

Progress :The first funding for this task arrived late in FY 2003. The majority of the year was devoted to planning project components and putting contracts, memoranda of understanding, and interagency agreements in place. Field collections of an important corn pest targeted by genetically modified corn (the western corn rootworm, Diabrotica virgifera virgifera) took place during the summer of 2003. Current work is focused on (1) Development of molecular genetic markers for evaluations of neutral and resistance-related loci in D. virgifera virgifera (D. v. virgifera); (2) Evaluation of population genetic structure of D. v. virgifera, throughout the cornbelt; (3) Evaluation of population genetic structure of the Mexican corn rootworm, Diabrotica virgifera zeae (D. v. zeae) in Oklahoma and Texas; (4) Establishment of laboratory cultures of western corn rootworm (WCR) and developing methods to study resistance/tolerance to Bt corn in the lab; (5) Development and evaluation of a PCR assay for resistance monitoring; (6) Assessment of genes that are differentially expressed following Bt exposure, as possible indicators of exposure in non-target insects.

The following manuscripts and presentations were produced in 2003.

Stolz, U. (2003) Review of the scientific literature on the use of genetic monitoring for long-term ecosystem surveillance, with special attention to its use in agroecosystems

Blum, M., Stolz, U., and Bagley, M.J. Assessing possible ecological risks of genetically modified crops: gene expression assays and genetic monitoring of non-target organisms. Presented at: Science Forum 2003, Washington, DC, May 5-7, 2003.

Stolz, U., Blum, M., and Bagley, M.J. The evolution of resistance to plant incorporated protectants by targeted insect pests. Presented at: Science Forum 2003, Washington, DC, May 5-7, 2003

Relevance :Our Biotech research will support ORD's goal to develop and implement stewardship strategies to reduce ecosystem risks due to pesticide exposures under GPRA Goal 4 (Preventing Pollution and Reducing Risk in Communities, Homes, Workplaces and Ecosystems), Objective 1, Subobjective 2. The work will provide the EPA with the tools to evaluate risks associated with the next generation of genetically modified crops. The work is of primary importance to EPA's Office of Prevention, Pesticides, and Toxic Substances.

Clients :OPPTS, States, Regions, Tribes

Project IDs:

ID Code :19119

Project type :OMIS