1. Insecticide Resistance: Genes For Pest? Donnie Day

2. Overview  What is a GMO?  What is Bacillus thuringiensis ?  What is Bt Crops?  How does it work?  Bt Safety  Concerns

3. What is a GMO?  When a gene from one organism is purposely moved to improve or change another organism in a laboratory  It is also sometimes called "transgenic" for transfer of genes  GM techniques also allow traits from different organisms to be applied, such as pest resistance.

5. How its done  Isolation of the gene(s) of interest  Insertion of the gene(s) into a transfer vector  Plant transformation  Selection of the modified plant cells  Regeneration into whole plants via tissue culture  Verification of transformation  Testing of plant  Safety assessment

6. What is Bacillus thuringiensis?  Bacterium that produces crystals protein (cry proteins), which are toxic to many species of insects.  Bt belongs to the family of bacteria, Bacillus cerus  Bt is also used in urban aerial spraying programs, and in transgenic crops.

7. What is a Bt Crop?  Plants that have been modified with short sequences of genes from Bt to express the crystal protein Bt makes.

9. How does it work? 1. Insect eats Bt crystals and spores. 2. The toxin binds to specific receptors in the gut and the insects stops eating. 3. The crystals cause the gut wall to break down, allowing spores and normal gut bacteria to enter the body. 4. The insect dies as spores and gut bacteria proliferate in the body.

10. Bt Safety  Bt products are found to be safe for use in the environment and with mammals.  Bt has not been shown to have any chronic toxicity or any carcinogenic effects.

11. Concerns  Resistance  Cross-contamination of genes  Invasiveness

12. How?  In a population of insects there may be a few individuals that carry the genes for resistance  With every generation the number of resistant insects increase.  Unavoidable?

13.  diamondback moth is the only insect found to have developed resistance

14. Minimizing Resistance  Alternate Bt applications with synthetic insecticides  Crop rotation  Refuge Planting

15. Refuge Planting

17. Summary  What is a GMO?  What is Bacillus thuringiensis ?  What is Bt Crops?  How does it work?  Bt Safety  Concerns

18. Questions ?