Levels of expressed Cry1Ab toxin in genetically modified corn DK-440-BTY (YIELDGARD) and stubble
Abstract number: L3-005
Szekacs A., Juracsek J., Polgar L. A., Darvas B.
The production of the Bacillus thuringiensis-originated Cry1Ab toxin (Bt-toxin) in the genetically modified (GM) DK-440-BTY corn was analyzed in a 3-year period using immunoanalytical detection. By biochemical analysis of the transgenic proteins with specific antibodies, the content of the three-domain d-endotoxin was monitored throughout each entire vegetation period and was compared to that detected in isogenic corn line. Toxin content was found to be in the order: leaves > anther wall > root > stem > seed > pollen. Relative toxin content in the leaves increased until June, and slightly dropped afterwards. The toxin level produced on the plantation area was calculated to be 1500–2000 times higher than toxin dosage corresponding to registered applications of the Bt-toxin-based biopesticide DIPEL. Thus, the GM corn represents a 1500–2000 times higher environmental toxin load than registered non-biotechnological toxin applications. Nearly 84% of the toxin content was produced in the leaves, the stem, seed, roots and the tassel represented 8, 4, 3 and 1%, respectively. Alarming that about 8% of the produced toxin remains on the area after harvest, and a significant part was found to persist in the stubble after 11 months. Although corn pollen contains low amounts of toxin, cross-pollination occurs on non-Bt-corn already in the first vegetation period, and seeds of the subsequent intraspecific hybrids contained one-third of the toxin content in DK-440-BTY.
Acknowledgments:
This research was supported by the Hungarian Ministry of Education (BIO-00042/2000) and the Ministry of Environment (K-36-01-00017/2002).
| Subject: |
L3 – Genomics in Protein Biotechnology/Protein Biotechnology |
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