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General Information

Document type
  • Peer-reviewed journal article
Study Type
  • Decomposition
  • field
GE organism
  • maize
GE trait
  • insect resistance
  • Switzerland


Safety for environment
  • mixed

Degradation of the Cry1Ab protein within transgenic Bacillus thuringiensis corn tissue in the field

Zwahlen, C; Hilbeck, A; Gugerli, P; Nentwig, W
Molecular Ecology. 2003 March. 12(3):765–775

Link to full text (journal may charge for access)

DOI: 10.1046/j.1365-294X.2003.01767.x


Large quantities of Bacillus thuringiensis (Bt) corn plant residue are left in the field after harvest, which may have implications for the soil ecosystem. Potential impacts on soil organisms will also depend on the persistence of the Bt toxin in plant residues. Therefore, it is important to know how long the toxin persists in plant residues. In two field studies in the temperate corn-growing region of Switzerland we investigated degradation of the Cry1Ab toxin in transgenic Bt corn leaves during autumn, winter and spring using an enzyme-linked immunosorbent assay (ELISA). In the first field trial, representing a tillage system, no degradation of the Cry1Ab toxin was observed during the first month. During the second month, Cry1Ab toxin concentrations decreased to ≈ 20% of their initial values. During winter, there was no further degradation. When temperatures again increased in spring, the toxin continued to degrade slowly, but could still be detected in June. In the second field trial, representing a no-tillage system, Cry1Ab toxin concentrations decreased without initial delay as for soil-incorporated Bt plants, to 38% of the initial concentration during the first 40 days. They then continued to decrease until the end of the trial after 200 days in June, when 0.3% of the initial amount of Cry1Ab toxin was detected. Our results suggest that extended pre- and post-commercial monitoring are necessary to assess the long-term impact of Bt toxin in transgenic plant residues on soil organisms.


Bacillus thuringiensis; degradation; ELISA; persistence; soil; transgenic plants


Funding source
  • Not reported
Funding country
  • Not reported
Funding type
  • Not reported

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Cite this study


Zwahlen, C, A Hilbeck, P Gugerli, W Nentwig. "Degradation of the Cry1Ab protein within transgenic Bacillus thuringiensis corn tissue in the field." Molecular Ecology 12.3 (2003): 765–775. Web. 5 Dec. 2023.


Zwahlen, C., Hilbeck, A., Gugerli, P., & Nentwig, W. (2003). Degradation of the Cry1Ab protein within transgenic Bacillus thuringiensis corn tissue in the field. Molecular Ecology, 12(3), 765–775. doi:10.1046/j.1365-294X.2003.01767.x

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