Biotechnology Risk Assessment: a View from Plant Pathology1

This file was created by scanning the printed publication. Errors identified by the software have been corrected; however, some errors may remain. Chapter33 Biotechnology Risk Assessment: A View From Plant Pathology1 X. B. Yang biological systems elevates the potential for ecosystem impacts. Some propose that genetic engineering could cre Introduction ate ecologically high-risk, super-competitive organisms that could alter ecosystem function. Biotechnology has Agricultural science has established a framework for bio generated new concepts and potentials for modifying bio logical impact assessment through past work. Various risk logical systems. Biological scientists are asked to design assessments for diverse areas of agriculture, resulted in an predictable biological systems for human needs while sus accumulation of considerable information. Baseline infor taining natural resources (Fulkerson 1987). Many biologi mation for biological impact assessment dates from the last cal science disciplines assess potential ecosystem impacts century (Fulkerson 1987). One type of biological impact from genetic engineering technology. Forestry initially fo assessment is the environmental impact assessment on the cused on poplar, an agricultural crop grown worldwide release of transgenic poplar. Plant pathologists played a for fiber, energy, and wood production, to assess the im major role in an early experimental release of transgenic pact of biotechnology on the environment (Klopfenstein poplar (McNabb et al. 1991). Plant pathology has provided et al. 1991, 1993; McNabb et al. 1991). much of the information for developing biological impact Biological impact assessment estimates the potential or assessment (Teng and Yang 1993) with a focus on complex actual impact, including hazards and benefits, of the pres microbe-related risk assessments. This paper discusses bio ence, introduction, or entrance of specific organisms into logical risk assessment for woody plants compared to her a biological system. Impacts can arise from the introduc baceous crops, specifically: 1) the need for and status of tion of any new technology into a natural ecosystem, risk assessment; 2) risk assessment concepts; and 3) risk whether a physical product or knowledge-based process. assessment methodology. All impacts should be assessed. In microbial ecology, issues regarding testing and ap plication of biotechnological products are frequently dis cussed (GilJett 1986; Lindow et al. 1989; Turgeon and Yoder 1985). Because of the nature of plant pathogens, and be Need for and Status of cause microbes form the lower trophic levels of most eco Risk Assessment systems, genetic engineering of organisms has been considered a risk to ecosystem stability. This potential for environmental risk is associated with the: 1) creation of a Biotechnology has changed some sectors of agriculture new pest; 2) enhancement of existing pathogens through into industries perceived as high risk and high return. The gene transformation; 3) harm to nontarget species; or 4) increasing ability to manipulate genetic components in any other ecosystem disruption. Early environmental im pact assessment of transgenic microbes involved the po tential application of non-ice-nucleating bacteria to prevent frost injury in California (Andow et al 1989; Lindow et al , Klopfenstein, N.B.; Chun, Y. W.; Kim, M.-S.; Ahuja, M.A., eds. 1983; Lindow and Panopoulus 1988). Currently, some epi Dillon, M.C.; Carman, R.C.; Eskew, L.G., tech. eds. 1997. demiological studies concern horizontal gene transfers in Micropropagation, genetic engineering, and molecular biology microbes such as those using Colletotrichum spp. for bio of Populus. Gen. Tech. Rep. RM-GTR-297. Fort Collins, CO: logical weed control (TeBeest et al. 1992). U.S. Department of Agriculture, Forest Service, Rocky Mountain The environmental impact of transgenic woody plants Research Station. 326 p. is a major issue in the development and application ofbio- 264 Biotechnology Risk Assessment: A View From Plant Pathology technology. A concern of risk assessment is the potential cently, risk assessment was defined as a process to deter for transgenic plants to displace native species (Duchesne mine and evaluate potential risks, and the magnitude and 1993; Pimentel et al. 1990; Rogers and Parkes 1995; Teng probability of those risks occurring (Teng and Yang 1993). and Yang 1993; Tiedje et al. 1989). Similarly, the potential There are 2 steps in risk assessment: 1) risk determination, of transgenic woody plants to replace wild flora is also a which is identifying and characterizing the risk source; and major concern. The need to assess the biotechnological 2) risk estimation, which is estimating the probability and impacts on nontargeted pests and nonpests, and the po magnitude of adverse effects from an introduced organ tential threat this poses to forest ecosystems has been dis ism in an ecosystem (figure 1). Biotechnology-related im cussed (Duchesne 1993). Unfortunately, assessing the pact assessment is concerned with the estimation of environmental fate and impact of transgenic trees lags potential or actual consequences after introduction of behind the ability to create them. Methods are needed to transgenic products into an ecosystem. Risk assessment assess the environmental impact of transgenic trees to before field testing may be premature unless the risk is safely incorporate them into forestry research and silvi known (Teng 1991). culture. Biotechnology-related risk concerns hazards that are Risks associated with transgenic plants have been ex negative acts or events in quantitative terms with the prob tensively discussed (Gould 1988; Pimental et al. 1990; ability of risk. In this concept, risk assessment includes: 1) Tiedje et al. 1989). In 1987, transgenic tomato plants were identifying the hazard; 2) characterizing the risk; and 3) the first field-tested, genetically engineered, food crop managing the risk. The first 2 steps are similar to the risk (Muench 1990). A gene encoding the coat protein of to determination step previously mentioned. Risk; in both of bacco mosaic virus (TMV) was introduced into tomato the above contexts, is used in plant pathogen-related as plants for virus resistance. Risks associated with such a sessments; however, the concept of risk changes with the release are the potential formation of a virus with altered discipline or situation. For example, risk is also consid vectors and new host ranges and the possibility of new ered the product of probability and the impact of a haz gene combinations (Zoeten 1991).Alternatively, such new ard, where hazard is any undesirable event (Evenhuis and combinations will likely occur less than that in nature (Falk Zadoks 1991). and Bruening 1994). In other countries, various transgenic "Monitoring," repetitive measurements made to specify agricultural plants are at different stages leading up to the state of a system over time, does not include the data field tests (e.g., tungro-resistant rice and virus X-resistant interpretation. Monitoring can provide a "time series," potato). In the scientific community, a consensus is emerging on how much biosafety is needed. However, until a common policy is agreed upon, countries will continue to have dif fering guidelines. Transgenic hybrid poplar trees were used Risk Determination as an early first field test to assess the risk of transgenic woody plants (McNabb et al. 1991). The risk of harmful gene transfer via pollen dispersal was considered + (McPartlan and Dale 1994; Sawahel1994; Williamson 1993). Data and Information Database J A procedure to assess such risk was proposed in the Neth Generation "-----_.( erlands (Evenhuis and Zadoks 1991). However, method ology has not been developed. Teng and Yang (1993) + proposed an outline for assessing the microbe-related risk on herbaceous crops. A conceptual risk assessment out System Synthesis line includes the common principles of impact assessment from different specializations, many of which are appli y cable to risk assessment for a woody crop such as poplar. + ( Prediction - GIS ~ l i_ ~c~ Concepts of Risk Assessment Risk Interpretation l...tiv The National Academy of Sciences (1983) defines "risk assessment" as the use of scientific methods, models, and Figure 1 . Schematic of risk assessment process in the data to develop information about specific risks. More re- context of biological impact assessment. USDA Forest Service Gen. Tech. Rep. RM-GTR-297. 1997. 265 Section V Biotechnological Applications which is a collection of observations made sequentially in bility to prediction; and 3) be sensitive to hazard. The early time to obtain "background" or "baseline information" field-test of transgenic poplars at Iowa State University (Duniker 1989). The background or baseline information had a well defined operational endpoint, which was to is a description of conditions or dynamics existing in an measure growth of transgenic poplars in comparison to ecosystem before an intervention, such as introducing a nontransgenic poplars under field conditions (McNabb et genetically engineered microbe (GEM), and serves as a al. 1991). check for any assessment. Statistically, a system baseline may be the inherent variability of an ecosystem. By using different statistical techniques, such as a time-series analy sis, variability of system output can be partitioned into inherent variability (regular pattern) and noise. For ex Assessment Methodology ample, Jacobi

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