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Record information and status
Record ID
Date of creation
2012-05-09 14:13 UTC (dina.abdelhakim@cbd.int)
Date of publication
2012-05-09 14:13 UTC (dina.abdelhakim@cbd.int)

General Information
Risk assessment of toxins derived from Bacillus thuringiensis-synergism, efficacy, and selectivity
Christoph Then
Author’s contact information
Scouting Biotechnology,
Frohschammerstr. 14,
80807 Munich, Germany

e-mail: christoph.then@scouting-biotech.de
  • English
Publication date
Summary, abstract or table of contents

Background, aim, and scope This review deals with publications concerning the mode of action of Bt proteins and their potential synergism with extrinsic factors. The aim was to assess the impact of those factors especially regarding selectivity and efficacy of Bt toxins and to discuss possible gaps in current risk assessment of genetically engineered plants expressing Bt toxins.

Main features The review shows that several extrinsic factors are able to influence the selectivity and efficacy of Bt toxins. The findings are seen as being relevant for risk assessment in Bt plants. This conclusion is derived by discussing current state of knowledge about the mode of action of Bt proteins, unexpected effects on non-target organism, and the way how modified Bt toxins are expressed in genetically engineered plants.

Results Several publications have been identified that show that certain factors and synergism can impact efficacy and selectivity of Bt toxins. These extrinsic factors are various and include other Bt toxins or parts from the spore of Bacillus thuringiensis as well as certain enzymes, environmental stress, non-pathogenic microorganisms, and infectious diseases.

Discussion Research on the underlying mechanism of observed synergism might help to explain some of the effects found in non-target organisms. In general, possible synergism of Bt toxins with extrinsic factors can be relevant for risk assessment of genetically engineered Bt plants since they expose a modified Bt toxin to the environment under various conditions and over a long period of time.

Conclusions Risk assessment of genetically engineered plants should put into question the general assumption of a high selectivity and a linear dose-response relationship in the toxicity of Bt proteins. Both selectivity and efficacy can be influenced by synergism, which can provoke unexpected and undesired effects in non-target organisms.

Perspectives It is suggested that systematic research be promoted on synergism between Bt toxins and potential extrinsic factors that could impact the spectrum of susceptible organisms. This research should become a prerequisite for risk assessment of Bt plants.
Thematic areas
  • Scientific and technical issues
    • Risk assessment
Background material to the “Guidance on risk assessment of living modified organisms”
Is this document is recommend as background material for the “Guidance on Risk Assessment of Living Modified Organisms”
Section(s) of the “Guidance on Risk Assessment of Living Modified Organisms” this background material is relevant
Additional Information
Type of resource
  • Article (journal / magazine / newspaper)
  • Report / Review / Fact sheet / Notes
DOI 10.1007/s11356-009-0208-3
Publisher and its location
© The Author(s) 2009
7 page PDF
Environmental Science and Pollution Research
Keywords and any other relevant information
Keywords: Keywords Bt toxin, Extrinsic factors, Genetically engineered plants, Non-target organism, Risk assessment, Synergism, Toxicity

Citation: Environ Sci Pollut Res (2010) 17:791-797