No Detection of Cry1Ac Protein in Soil After Multiple Years of Transgenic Bt Cotton (Bollgard) Use

By G. Head, J. B. Surber, J. A. Watson, John W. Martin, J. Duan. 2002

150 citations recorded by the source corpus.

Abstract Soil samples were collected from within and outside six fields where insect-resistant transgenic cotton (Bollgard) encoding the Bacillus thuringiensis Berliner (Bt) subsp. kurstaki cry1Ac gene had been grown and subsequently incorporated into soil by postharvest tillage for 3–6 consecutive years. The level of Cry1Ac protein in these samples (collected 3 mo after the last season’s tillage) was evaluated using both enzyme-linked immunosorbent assays (ELISA) and bioassays with a susceptible insect species, Heliothis virescens (F.), the tobacco budworm. Both methods revealed that no detectable Cry1Ac protein was present in any of the soil samples collected from within or outside the Bollgard fields. Based on the results from reference standards, the limit of detection for the ELISA was 3.68 ng of extractable protein per gram of soil, and that of the bioassay (measured by EC50) was 8 ng of biologically active protein per gram of soil. Together, these findings demonstrate that the amount of Cry1Ac protein accumulated as a result of continuous use of transgenic Bt cotton, and subsequent incorporation of plant residues into the soil by postharvest tillage, is extremely low and does not result in detectable biological activity.

Subfields: Molecular Biology, Plant Science

View Paper: https://www.semanticscholar.org/paper/e7ed3f638f39d1fa0229e581cfcd55a01e786f72

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In Molecular Biology

1. Paul Henning Krogh
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1. Paul Henning Krogh
2. G. Dively

Citations in the corpus

• Can Bacillus thuringiensis (Bt) corn residues and Bt-corn plants affect life-history traits in the earthworm Aporrectodea caliginosa? (2006, background): “Most studies show that Bt-protein is degraded or inactivated in soil within weeks ( Head et al., 2002; Hopkins and Gregorich, 2003).”
• Impact of Transgenic VIP3A × Cry1Ab Lepidopteran-resistant Field Corn on the Nontarget Arthropod Community (2005, background): “Laboratory and Þeld studies thus far have shown no consistent adverse effects ofBt crops orBt proteins on micro- and macroorganisms in the soil (Yu et al. 1997, Sims and Martin 1997, Saxena and Stotzky 2001, Head et al. 2002, Aldeeb et al. 2003).”
• Detectability of Coleopteran-specific Cry3Bb1 Protein in Soil and Its Effect on Nontarget Surface and Below-Ground Arthropods (2005, background): “The results are in agreement with other studies using different Bt protein, when spiked in different types of soil (Cry1Ab: Palm et al. 1994, Cry1Ac: Head et al. 2002).”