Risk Assessment Of Transgenic Crops Research Articles

Monitoring reduced accumulation and risk evaluation of Cry1Ca during food chain transfer from genetic engineered plant to endoparasitoid.

The potential risk of insecticidal proteins produced by genetically engineered (GE) plants to non-target organisms have long been an ecotoxicological concern. Apanteles chilonis, an important endoparasitoid of rice pest Chilo suppressalis, is potentially exposed to Bacillus thuringiensis (Bt) endotoxins through a food chain of transgenic Bt rice - C. suppressalis - A. chilonis, thus, a rigorous risk assessment is urgently needed. Here we combined a tri-trophic bioassay system with high dose exposure approach using C. suppressalis hemolymph as the carrier of insecticidal protein to evaluate the biosafety of Cry1Ca to A. chilonis. Cry1Ca protein could be transmitted and retained along the food chain and remains bioactive in the hemolymph of C. suppressalis during the pre-adult duration of A. chilonis. No significant differences in pre-adult period, male and female longevity, adult fecundity and weight, emergence rate, and sex ratio were observed when A. chilonis parasitized C. suppressalis feeding on cry1Ca rice compared to control treatment. However, the pupal period and weight were significantly prolonged and decreased. When A. chilonis parasitized on C. suppressalis injected with a high dosage of Cry1Ca protein, no adverse effects on the life-history parameters, peroxidase (POD), superoxide dismutase (SOD), and glutathione reductase (GR) of A. chilonis were observed, demonstrating that the host quality mediates adverse effects during the food chain. We confirmed that Cry1Ca posed no ecological risk to the non-target endoparasitoid A. chilonis. This study may serve as an example for future risk assessment of transgenic crops to non-target endoparasitoids. This article is protected by copyright. All rights reserved.

Transportability of Conclusions From Confined Field Trials: A Case Study Using the Virus Resistant Transgenic Bean Developed in Brazil.

The conceptual framework for Data Transportability, builds on the premise that well-designed studies conducted for the environmental and food/feed risk assessment of transgenic crops may be transportable across geographies. Beyond individual data, provided that certain criteria are met, the general conclusions of comparative assessments of a transgenic crop with its conventional counterpart would also be transportable. In spite of this, many regulatory agencies still require in-country field trials to complete risk assessments of transgenic crops. A sub-team from ILSI Argentina’s (International Life Sciences Institute, Argentina. www.ilsi.org.ar) Biotechnology Working Group tested the applicability of the transportability concept to the case of the golden mosaic virus-resistant transgenic bean, developed by EMBRAPA (EMBRAPA: Brazilian Agricultural Research Corporation). To this end, regulatory confined field trials (CFTs) carried out in Brazil to gather agro-phenotypic and compositional data were analyzed. The transportability of the conclusions of these studies to the bean cropping areas in Argentina was assessed as a conceptual exercise (with no intention to conclude on the biosafety of the common bean event). Comparative studies included the transgenic bean and its conventional parental line and were run in different agroecological environments so that any relevant differences could be observed. The main criteria to enable transportability were set by the sub-team and found to be met by the CFTs carried out in Brazil to inform a potential risk evaluation for Argentina.

Familiarity in the Context of Risk Assessment of Transgenic Crops: Focus on Some Countries in the Americas.

Problem formulation is the formal opening stage of a risk assessment that determines its purpose and scope and hence guides the gathering of information data. The concepts of familiarity and history of safe use are an integral part of problem formulation. These concepts do not replace the case-by-case approach and are not taken as safety standards but are valuable components of the process that shape the generation of plausible, testable risk hypotheses. The International Life Sciences Institutes in Brazil and Argentina have facilitated numerous discussions on the scientific principles for risk assessment of transgenic crops in the Latin American region in the past 5–6 years. The session held at ISBR 15th elaborated on the familiarity concept and derived tools and their role in the evolution of risk evaluation criteria. Examples of how different countries in the Americas interpret and apply these conceptual tools show that familiarity is a valuable concept, although terms are very often confused and vaguely defined. Formalizing these terms with clear definitions and scope of application in guidelines and regulatory documents would reduce ambiguity, enhance predictability, and add transparency to the evaluation processes.

The integrated risk assessment of transgenic crops

The integrated risk assessment of transgenic crops

Does transgenic Cry1Ac + CpTI cotton pollen affect hypopharyngeal gland development and midgut proteolytic enzyme activity in the honey bee Apis mellifera L. (Hymenoptera, Apidae)?

The transgenic Cry1Ac (Bt toxin) + CpTI (Cowpea Trypsin Inhibitor) cotton cultivar CCRI41 is increasingly used in China and potential side effects on the honey bee Apis mellifera L. have been documented recently. Two studies have assessed potential lethal and sublethal effects in young bees fed with CCRI41 cotton pollen but no effect was observed on learning capacities, although lower feeding activity in exposed honey bees was noted (antifeedant effect). The present study aimed at providing further insights into potential side effects of CCRI41 cotton on honey bees. Emerging honey bees were exposed to different pollen diets using no-choice feeding protocols (chronic exposure) in controlled laboratory conditions and we aimed at documenting potential mechanisms underneath the CCRI41 antifeedant effect previously reported. Activity of midgut proteolytic enzyme of young adult honey bees fed on CCRI41 cotton pollen were not significantly affected, i.e. previously observed antifeedant effect was not linked to disturbed activity of the proteolytic enzymes in bees' midgut. Hypopharyngeal gland development was assessed by quantifying total extractable proteins from the glands. Results suggested that CCRI41 cotton pollen carries no risk to hypopharyngeal gland development of young adult honey bees. In the two bioassays, honey bees exposed to 1 % soybean trypsin inhibitor were used as positive controls for both midgut proteolytic enzymes and hypopharyngeal gland proteins quantification, and bees exposed to 48 ppb (part per billion) (i.e. 48 ng g(-1)) imidacloprid were used as controls for exposure to a sublethal concentration of toxic product. The results show that the previously reported antifeedant effect of CCRI41 cotton pollen on honey bees is not linked to effects on their midgut proteolytic enzymes or on the development of their hypopharyngeal glands. The results of the study are discussed in the framework of risk assessment of transgenic crops on honey bees.

Risk assessment strategies for transgenic plants

Advances in recombinant DNA technology have created advantages for the development of plants with high agro-economical values. Since the production of transgenic plants, some issues concerning the safe use of these plants and their products have been under debate throughout the world. In this respect, the potential risks and benefits of transgenic plants need to be evaluated objectively. Risk assessment of transgenic crops is a basic prerequisite for monitoring the possible risks that could arise upon the release and use of transgenic plants. To get a meaningful tool for decision making, risk assessment needs to be carried out in a scientific sound and transparent manner. There are specific governmental regulations in many countries for the safety assessment of genetically modified (GM) crops. Furthermore, there are some international agreements, which regulate the cultivation and commercialization of transgenic plants and their derivatives. Internationally accepted risk assessment strategies have been performed to evaluate the safe use of a large variety of GM crops. The main objectives of these regulations and risk assessment strategies are focused to protect human/animal health and the environment.

Assays of the production of harmful substances by genetically modified oilseed rape (Brassica napus L.) plants in accordance with regulations for evaluating the impact on biodiversity in Japan

Environmental risk assessment of transgenic crops is implemented under the Cartagena Protocol domestic law in accordance with guidelines for implementing the assessment established by the Ministry of Agriculture, Forestry and Fisheries (MAFF) and the Ministry of Environment (MOE) in Japan. Environmental risk assessments of transgenic crops are implemented based on the concept of 'substantial equivalence' to conventional crops. A unique requirement in Japan to monitor the production of harmful substances, or allelochemicals, is unparalleled in other countries. The potential for allelochemicals to be secreted from the roots of transgenic crops to affect other plants or soil microflora or for substances in the plant body to affect other plants after dying out must be evaluated. We evaluated the allelopathic potential of seven transgenic oilseed rape (Brassica napus L.) lines that express glufosinate tolerance in terms of substantial equivalence to conventional oilseed rape lines, and established evaluation methods. Our results indicate no potential production of allelochemicals for any of the seven transgenic oilseed rape lines compared with conventional oilseed rape lines.

Sunlit mesocosms designed for pollen confinement and risk assessment of transgenic crops

To minimize concerns about the ecological consequences of wind and insect dispersal of pollen and the potential of gene flow from experimental genetically modified (GM) crops to compatible relatives, we have modified outdoor sunlit open top chambers (OTCs) for use with GM plants. We have redesigned 21 cylindrical OTCs, commonly used to study the effects of atmospheric pollutants, by adding (1) a pollen filter at the top of each unit to minimize the possibility of the escape of GM pollen; with pollen filters in place, the OTCs are referred to as mesocosms, (2) an evaporative cooler to help mitigate elevated temperatures during the summer months, and (3) an automated watering system that eliminates the need to enter a mesocosm for irrigation during pollination, thereby minimizing potential pollen escape and entry of insect pollinators. Each sunlit mesocosm contains three large plastic pots (each with 1.2-m2 surface area) that simulate field plots and that contain a constructed plant community. For example, the community may consist of a GM and a non-GM cultivar of canola (Brassica napus), compatible weedy relatives, and non-compatible species that may be found in mesic disturbed areas such as roadsides or ditches beyond crop fields. The sunlit mesocosms provide a well-replicated outdoor testing system that confines pollen and that can be used to precede or supplement field tests that evaluate the potential ecological consequences of transgenic crops. The mesocosms are proposed as test systems in which transgenic crops and other plants (e.g., biofuel crops) that have been proposed to be grown in new geographies, or plants that produce novel compounds, may be studied to evaluate their potential effects on plant communities. The pollen confinement and insect exclusion features of our mesocosms may also minimize exposure of sensitive humans and insect pollinators to pollen and cellular debris from other plant parts.

Use of airborne remote sensing to detect riverside Brassica rapa to aid in risk assessment of transgenic crops

High resolution descriptions of plant distribution have utility for many ecological applications but are especially useful for predictive modeling of gene flow from transgenic crops. Difficulty lies in the extrapolation errors that occur when limited ground survey data are scaled up to the landscape or national level. This problem is epitomized by the wide confidence limits generated in a previous attempt to describe the national abundance of riverside Brassica rapa (a wild relative of cultivated rapeseed) across the United Kingdom. Here, we assess the value of airborne remote sensing to locate B. rapa over large areas and so reduce the need for extrapolation. We describe results from flights over the river Nene in England acquired using Airborne Thematic Mapper (ATM) and Compact Airborne Spectrographic Imager (CASI) imagery, together with ground truth data. It proved possible to detect 97% of flowering B. rapa on the basis of spectral profiles. This included all stands of plants that occupied >2m square (>5 plants), which were detected using single-pixel classification. It also included very small populations (<5 flowering plants, 1-2m square) that generated mixed pixels, which were detected using spectral unmixing. The high detection accuracy for flowering B. rapa was coupled with a rather large false positive rate (43%). The latter could be reduced by using the image detections to target fieldwork to confirm species identity, or by acquiring additional remote sensing data such as laser altimetry or multitemporal imagery.

형질전환작물의 위해성평가와 품종등록

형질전환작물 상업화의 최종 규제단계는 위해성심사와 품종출원이다. 위해성심사를 위한 형질전환작물의 위해성 평가는 광범위한 과학자 네트워크, 고비용과 오랜 기간을 필요로 한다. 따라서 형질전환작물 개발자는 우수한 형질의 개발 이외에 위해성평가에 대한 이론적 및 전략적 측면을 부가적으로 고려해야 한다. 유전자변형생물체의 위해성평가에 대한 일반적인 개념은 화학물 위해성평가로부터 유래하였다. 그러나 생물체가 가지는 복잡성 때문에 실질적동등성과 친숙성으로 대표되는 비교접근 방법이 개발되어 왔다. 실제적인 측면에서 통합적인 위해성평가는 유전자이동성, 독성과 알레르기와 같은 개별 위해성평가보다 더 어렵다. 형질전환 계통의 품종출원을 위해서는 위해성평가 단계에서부터 품종보호요건을 고려한 평가자료 생산과 위해성 심사 승인 계통을 이용한 다양한 LMO 품종 육종전략이 필요하다. Final regulatory steps for commercialization of transgenic crops are risk assessment and variety registration. The risk assessment of transgenic crops requires broad network of scientists, high cost and long term. Developers of transgenic crops, therefore, face to additional challenges to consider theoretical and strategic aspects on risk assessment. The general concept for risk assessment of genetically modified organisms was derived from chemical risk assessment. Due to the complexity of organisms, however, comparative approaches that are substantial equivalence and familarity have been developed. In practical view, the integration of risk assessment is more difficult than the evaluation of each risk factors involving gene flow, toxicity and allergenicity. Variety registration of transgenic crops requires the results of risk assessment compared with non-GM crops and agronomic data analyzed with standard varieties. For economic and fast commercialization, risk assessment process should combined with condition of cultivation test for variety registration.

Transcomplementation and synergism in plants: implications for viral transgenes?

In plants, viral synergisms occur when one virus enhances infection by a distinct or unrelated virus. Such synergisms may be unidirectional or mutualistic but, in either case, synergism implies that protein(s) from one virus can enhance infection by another. A mechanistically related phenomenon is transcomplementation, in which a viral protein, usually expressed from a transgene, enhances or supports the infection of a virus from a distinct species. To gain an insight into the characteristics and limitations of these helper functions of individual viral genes, and to assess their effects on the plant-pathogen relationship, reports of successful synergism and transcomplementation were compiled from the peer-reviewed literature and combined with data from successful viral gene exchange experiments. Results from these experiments were tabulated to highlight the phylogenetic relationship between the helper and dependent viruses and, where possible, to identify the protein responsible for the altered infection process. The analysis of more than 150 publications, each containing one or more reports of successful exchanges, transcomplementation or synergism, revealed the following: (i) diverse viral traits can be enhanced by synergism and transcomplementation; these include the expansion of host range, acquisition of mechanical transmission, enhanced specific infectivity, enhanced cell-to-cell and long-distance movement, elevated or novel vector transmission, elevated viral titre and enhanced seed transmission; (ii) transcomplementation and synergism are mediated by many viral proteins, including inhibitors of gene silencing, replicases, coat proteins and movement proteins; (iii) although more frequent between closely related viruses, transcomplementation and synergism can occur between viruses that are phylogenetically highly divergent. As indicators of the interoperability of viral genes, these results are of general interest, but they can also be applied to the risk assessment of transgenic crops expressing viral proteins. In particular, they can contribute to the identification of potential hazards, and can be used to identify data gaps and limitations in predicting the likelihood of transgene-mediated transcomplementation.

Ethics in the Societal Debate on Genetically Modified Organisms: A (Re)Quest for Sense and Sensibility

Via a historical reconstruction, this paper primarily demonstrates how the societal debate on genetically modified organisms (GMOs) gradually extended in terms of actors involved and concerns reflected. It is argued that the implementation of recombinant DNA technology out of the laboratory and into civil society entailed a “complex of concerns.” In this complex, distinctions between environmental, agricultural, socio-economic, and ethical issues proved to be blurred. This fueled the confusion between the wider debate on genetic modification and the risk assessment of transgenic crops in the European Union. In this paper, the lasting skeptical and/or ambivalent attitude of Europeans towards agro-food biotechnology is interpreted as signaling an ongoing social request – and even a quest – for an evaluation of biotechnology with Sense and Sensibility. In this (re)quest, a broader-than-scientific dimension is sought for that allows addressing the GMO debate in a more “sensible” way, whilst making “sense” of the different stances taken in it. Here, the restyling of the European regulatory frame on transgenic agro-food products and of science communication models are discussed and taken to be indicative of the (re)quest to move from a merely scientific evaluation and risk-based policy towards a socially more robust evaluation that takes the “non-scientific” concerns at stake in the GMO debate seriously.

A large‐scale field study of transgene flow from cultivated rice (Oryza sativa) to common wild rice (O. rufipogon) and barnyard grass (Echinochloa crusgalli)

The introgression of transgenes into wild relatives or weeds through pollen-mediated gene flow is a major concern in environmental risk assessment of transgenic crops. A large-scale (1.3-1.8 ha) rice gene flow study was conducted using transgenic rice containing the bar gene as a pollen donor and Oryza rufipogon as a recipient. There was a high frequency of transgene flow (11%-18%) at 0-1 m, with a steep decline with increasing distance to a detection limit of 0.01% by 250 m. To our knowledge, this is the highest frequency and longest distance of gene flow from transgenic rice to O. rufipogon reported so far. On the basis of these data, an adequate isolation distance from both conventional and transgenic rice should be taken for in situ conservation of common wild rice. Meanwhile, there is no evidence of transgene introgression into barnyard grass, even when it has coexisted with transgenic rice containing the bar gene for five successive years. Thus, the environmental risk of gene flow to this weedy species is of little concern.

Principal component analysis and discriminant analysis (PCA–DA) for discriminating profiles of terminal restriction fragment length polymorphism (T-RFLP) in soil bacterial communities

To assess the impact of a transgenic crop on soil environment, we compared soil bacterial communities from the rhizospheres of cucumber green mottle mosaic virus (CGMMV)-resistant transgenic watermelon ( Citrullus vulgaris [Twinser] cv. Gongdae) and non-transgenic parental line watermelon at an experimental farm in Miryang, Korea. Soil microbial community structure was studied using terminal restriction fragment length polymorphism (T-RFLP) using HaeIII and HhaI enzymes on products from polymerase chain amplification reactions (PCR) of total DNA from rhizosphere. We used principal component analyses (PCA) to reduce dimensionality of T-RFLP profiles before comparison. On these PCA scores, we conducted discrimination analyses to compare soil microbial communities from the rhizosphere of transgenic and non-transgenic. Discriminant analyses indicate that microbial communities from rhizosphere of transgenic and non-transgenic watermelon did not differ with significance at 95% level. Our study could be used as a model case to assess the environmental risk assessment of transgenic crops on soil microbial organisms.

Tiered tests to assess the environmental risk of fitness changes in hybrids between transgenic crops and wild relatives: the example of virus resistantBrassica napus

Over the last 20 years, there has been much research aimed at improving environmental risk assessment of transgenic crops. Despite large amounts of data, decisions to allow or prohibit the release of transgenic crops remain confused and controversial. We argue that part of the reason for confusion is the lack of clear definitions of components of the environment that should be protected, and, as a consequence, there is no way to judge the relevance of data collected under the auspices of 'environmental risk assessment'. Although this criticism applies to most aspects of environmental risk assessment of transgenic crops, it is most pertinent to effects that might result from an increase in plant fitness, often referred to as increased weediness. Environmental risk assessment of weediness is regarded as complicated: an increase in the fitness of a transgenic plant compared with non-transgenic counterparts will be the result of an interaction between the altered plant phenotype and an enormous number of environmental variables. This has led to the idea that risk assessment of weediness needs to "understand" these interactions, with the implication that exhaustive data are required. Here we argue that environmental risk assessment of the weediness of transgenic plants need not be complicated. Analysis of the conditions that must be met for increased weediness to occur suggests a series of studies that starts with simple tests in the laboratory under "worst case" assumptions, and becomes increasingly complex and realistic should the simpler studies not indicate negligible risk with sufficient certainty. We illustrate how the approach might work for assessing the risks of increased weediness using the example of possible introgression of a gene for Turnip mosaic virus (TuMV) resistance from oilseed rape to certain wild Brassica species.

Costs of resistance: a test using transgenic Arabidopsis thaliana.

Evolutionary biologists have long attributed polymorphisms in resistance status to fitness costs of resistance traits. Nevertheless, pleiotropic fitness costs of resistance have been notoriously difficult to detect. We have transformed Arabidopsis thaliana with a mutant acetolactate synthase gene that confers resistance to the herbicide, chlorsulfuron. Our experiment revealed a 34% reduction in the lifetime seed production of transgenic, herbicide resistant Arabidopsis thaliana relative to their susceptible null segregants. Our experimental design allows us to conclude that this fitness cost of resistance is caused by the pleiotropic effect of the introduced acetolactate synthase gene rather than other potential costs associated with the plasmid or mutational changes induced by plant transformation. In addition, we can attribute the cost of resistance to the presence of the resistance gene rather than an increase in gene dosages. The implications of these results for the risk assessment of transgenic crops are discussed.