Fate of recombinant DNA and Cry1Ab protein after ingestion and dispersal of genetically modified maize in comparison to rapeseed by fallow deer (Dama dama)
The fate of recombinant DNA in fallow deer (Dama dama) was investigated by feeding a diet of isogenic or genetically modified (GM) maize expressing Cry1Ab protein against the European corn borer (Ostrinia nubilalis). To study the degradability of ingested DNA, polymerase chain reaction (PCR) assays were introduced to detect fragments of the endogenous, highly abundant chloroplast-specific rubisco gene, the maize-specific zein gene and the recombinant cry1Ab gene. PCR analysis revealed that small chloroplast- and maize-specific DNA fragments were detectable in contents of rumen, abomasums, jejunum, caecum and colon and occasionally in visceral tissues. In contrast, no fragments of the recombinant cry1Ab gene were detectable in gastrointestinal (GI) contents. The Cry1Ab protein was analysed using an enzyme-linked immunosorbent assay (ELISA) and immunoblotting technique. Neither ELISA nor immunoblotting yielded positive signals of immunoactive Cry1Ab protein in GI contents and tissues of fallow deer fed with GM maize. In conclusion, after uptake of GM maize, neither cry1Ab-specific gene fragments nor Cry1Ab protein were detected in the GI tract of fallow deer, indicating complete digestion of the GM maize. Additional investigations on the germination capacity of conventional rapeseed and maize seed after ingestion by fallow deer and faecal excretion (endozoochory) were performed to draw conclusions regarding a potential spreading of germinable GM crop seed by deer. Germination tests revealed that germinable rapeseed kernels were detectable in faeces; in contrast, no intact maize seeds were found in faeces.
KeywordsGenetically modified plants Bt-maize MON810 Bt176 Wildlife
This study was supported by the Federal Agency for Nature Conservation (BfN grant no. 20767432). We are indebted to former and recent members of the Physiology Weihenstephan (TUM, Freising) especially to Stefanie Rief, Steffi Wiedemann and M.A. Pinzón Olejua. Furthermore, we thank the staff of the working group Seed Testing and Seed Research in the Institute for Crop Science and Plant Breeding (Bavarian State Research Center, Freising) and Wildlife Biology and Management Unit (TUM, Freising) for their assistance during these studies. We also thank Prof. O. Rottmann (TUM Freising) for his support.
The authors affirm that the feeding studies with fallow deer dealt within this publication comply with the current law.
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