Biosafety assessment of transgenic Bt cotton on model animals

Ahmad Ali Shahid, Sadia Bano, Sana Khalid, Tahir Rehman Samiullah, Kamran Shahzad Bajwa, Muhammad Azam Ali


Background: To know the effects of transgenic crops on soil microorganisms, animals and other expected hazards due to the introduction of GM crops into the environment is critical both scientifically and environmentally. The work was conducted to study the effect of insecticidal Bt protein on Rats and Earthworms.  

Methods: For this purpose, animals like rat and soil organisms like Earthworm were selected. Rats were selected on the basis of its 95% homology on genomic, cellular and enzymatic level with human while earthworm were preferred on the basis of their direct contact with soil to evaluate the impact of Bt (Cry1AC) crop field soil on earthworm, secreted by root exudates of Bt cotton. Several physical, molecular, biochemical and histological analyses were performed on both Rats/Earthworms fed on standard diet (control group) as well containing Bt protein (experimental group).

Results: Molecular analyses such as immune Dot blot, SDS-PAGE, ELISA and PCR, confirmed the absence of Cry1Ac protein in blood and urine samples of rats, which were fed with Bt protein in their diet. Furthermore, histological studies showed that there was no difference in cellular architecture in liver, heart, kidney and intestine of Bt and non-Bt diet fed rats. To see the effect of Bt on earthworm two different groups were studied, one with transgenic plant field soil supplemented with grinded leaves of cotton and second group with non-Bt field soil.

Conclusions: No lethal effects of transgenic Bt protein on the survival of earthworm and rats were observed. Bradford assay, Dipstick assay ELISA demonstrated the absence of Cry1Ac protein in the mid-gut epithelial tissue of earthworm. The results of present study will be helpful in successful deployment and commercial release of genetically modified crop in Pakistan.

Full Text:



Foster K, Foster H, Dickson J. Gene therapy progress and prospects: Duchenne muscular dystrophy. Gene therapy, (2006); 13(24): 1677-1685.

Finkel E. Australia’s new era for GM crops. Science, (2008); 321(5896): 1629.

Bates SL, Zhao J-Z, Roush RT, Shelton AM. Insect resistance management in GM crops: past, present and future. Nature biotechnology, (2005); 23(1): 57-62.

Cannon RJ. Bt transgenic crops: risks and benefits. Integrated Pest Management Reviews, (2000); 5(3): 151-173.

Shelton AM, Zhao J-Z, Roush RT. Economic, ecological, food safety, and social consequences of the deployment of Bt transgenic plants. Annual review of entomology, (2002); 47(1): 845-881.

Gould F. Sustainability of transgenic insecticidal cultivars: integrating pest genetics and ecology. Annual review of entomology, (1998); 43(1): 701-726.

James C (2001) Global Review of Commercialized Transgenic Crops: 2001 (ISAAA Briefs No. 24 preview). International Service for the Acquisition of Agri-biotech Applications, Ithaca, NY.

Dale PJ, Clarke B, Fontes EM. Potential for the environmental impact of transgenic crops. Nature biotechnology, (2002); 20(6): 567-574.

Groot AT, Dicke M. Insect‐resistant transgenic plants in a multi‐trophic context. The Plant Journal, (2002); 31(4): 387-406.

Rahman M-u, Rashid H, Shahid AA, Bashir K, Husnain T, et al. Insect resistance and risk assessment studies of advanced generations of basmati rice expressing two genes of Bacillus thuringiensis. Electronic Journal of Biotechnology, (2007); 10(2): 241-251.

Dunger W, Fiedler H (1997) Methoden der Bodenbiologie–Gustav Fischer Verlag. Jena.

Lee KE Earthworms: their ecology and relationships with soils and land use. (1985); 144 Academic Press Inc. USA

Saxena D, Flores S, Stotzky G. Vertical movement in soil of insecticidal Cry1Ab protein from Bacillus thuringiensis. Soil Biology and Biochemistry, (2002); 34(1): 111-120.

McClintock JT, Schaffer CR, Sjoblad RD. A comparative review of the mammalian toxicity of Bacillus thuringiensis‐based pesticides. Pesticide Science, (1995); 45(2): 95-105.

Bradford MM. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Analytical Biochemistry, (1976); 72(1-2): 248-254.

El Sanhoty R, Abd El‐Rahman AA, Bögl KW. Quality and safety evaluation of genetically modified potatoes Spunta with Cry V gene: Compositional analysis, determination of some toxins, antinutrients compounds and feeding study in rats. Food/Nahrung, (2004); 48(1): 13-18.

Poulsen M, Kroghsbo S, Schrøder M, Wilcks A, Jacobsen H, et al. A 90-day safety study in Wistar rats fed genetically modified rice expressing snowdrop lectin Galanthus nivalis (GNA). Food and Chemical Toxicology, (2007); 45(3): 350-363.

Ahl Goy P, Warren G, White J, Privalle L, Fearing P, et al. Interaction of an insect tolerant maize with organisms in the ecosystem. Mitteilungen-Biologischen Bundesanstalt Fur Land Und Forstwirtschaft, (1995); 50-53.

Zwahlen C, Hilbeck A, Howald R, Nentwig W. Effects of transgenic Bt corn litter on the earthworm Lumbricus terrestris. Molecular Ecology, (2003); 12(4): 1077-1086.

Icoz I, Stotzky G. Fate and effects of insect-resistant Bt crops in soil ecosystems. Soil Biology and Biochemistry, (2008); 40(3): 559-586.

Van Der Merwe F, Bezuidenhout C, Van Den Berg J, Maboeta M. Effects of Cry1Ab transgenic maize on lifecycle and biomarker responses of the earthworm, Eisenia Andrei. Sensors, (2012); 12(12): 17155-17167.

Hammond B, Dudek R, Lemen J, Nemeth M. Results of a 13 week safety assurance study with rats fed grain from glyphosate tolerant corn. Food and Chemical Toxicology, (2004); 42(6): 1003-1014.

Juberg DR, Herman RA, Thomas J, Brooks KJ, Delaney B. Acute and repeated dose (28 day) mouse oral toxicology studies with Cry34Ab1 and Cry35Ab1 Bt proteins used in coleopteran resistant DAS-59122-7 corn. Regulatory Toxicology and Pharmacology, (2009); 54(2): 154-163.

Malatesta M, Boraldi F, Annovi G, Baldelli B, Battistelli S, et al. A long-term study on female mice fed on a genetically modified soybean: effects on liver ageing. Histochemistry and Cell Biology, (2008); 130(5): 967-977.


  • There are currently no refbacks.