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Transgenic Res (2012) 21:7788 DOI 10.1007/s11248-011-9509-7
ORIGINAL PAPER
Determination of insecticidal Cry1Ab protein in soil collected in the nal growing seasons of a nine-year eld trial of Bt-maize MON810
Helga Gruber Vijay Paul
Heinrich H. D. Meyer Martin Mller
Received: 21 September 2010 / Accepted: 27 March 2011 / Published online: 16 April 2011 Springer Science+Business Media B.V. 2011
Abstract Cultivation of genetically modied maize (Bt-maize; event MON810) producing recombinant d-endotoxin Cry1Ab, leads to introduction of the insecticidal toxin into soil by way of root exudates and plant residues. This study investigated the fate of Cry1Ab in soil under long-term Bt-maize cultivation in an experimental eld trial performed over nine growing seasons on four South German eld sites cultivated with MON810 and its near isogenic non Bt-maize variety. Cry1Ab protein was quantied in soil (\2 mm size) using an in-house validated ELISA method. The assay was validated according to the criteria specied in European Commission Decision 2002/657/EC. The assay enabled quantication of
Cry1Ab protein at a decision limit (CCa) of 2.0 ng Cry1Ab protein g-1 soil with analytical recovery in the range 49.188.9%, which was strongly correlated with clay content. Cry1Ab protein was only detected on one eld site at concentrations higher than the CCa, with 2.91 and 2.57 ng Cry1Ab protein g-1 soil in top and lower soil samples collected 6 weeks after the eighth growing season. Cry1Ab protein was never detected in soil sampled in the spring before the next farming season at any of the four experimental sites. No experimental evidence for accumulation or persistence of Cry1Ab protein in different soils under long-term Bt-maize cultivation can be drawn from this eld study.
Keywords Soil Genetically modied maize
Bt-maize MON810 Long-term eld trial Cry1Ab
protein Biosafety ELISA
Introduction
Bacillus thuringiensis (Bt) is a spore-forming bacterium that produces proteinaceous, crystalline inclusions during sporulation. These inclusions may contain one or more types of insecticidal crystal proteins (ICPs). The ICPs are solubilized and hydro-lysed in the midgut of larvae of susceptible insects, leading to the release of polypeptide toxins which can
H. Gruber (&) M. Mller
Bavarian State Research Center for Agriculture, Institute for Crop Science and Plant Breeding, Am Gereuth 8, 85354 Freising, Germanye-mail: [email protected]
H. Gruber V. Paul H. H. D. Meyer
Physiology Weihenstephan,...