GMOs in Agriculture

Federal Agencies involved in Food Safety The Federal Drug Administration (FDA) : responsible for the safety of food and animal feed products. The U.S. Department of Agriculture (USDA): oversees new plant varieties that are safe for the environment. Environmental Protection Agency (EPA): monitors and sets standards for pesticide levels in plants and determines what is acceptable for human consumption.

Think, Pair, Share Questions 1) Concerned citizens are upset about a new test field of GM strawberries and want to start a letter writing campaign. Which agency would be the most effective recipient of their letters? 2) A research lab is developing a new pesticide in the hopes of controlling the mediterranean fruit fly. Which agency will determine whether the product they develop is safe for consumers?

Technologies Used To Modify Plants gene guns antisense technology Ti plasmid based gene introduction

Gene Guns Uses tiny metal beads coated with DNA that are shot into the embryonic plant cell. Bt Corn was produced this way.

Antisense Technology When the DNA sequence of a protein is known, you can create a complementary sequence that will bind to the RNA before it reaches the ribosome.  Effectively turns the gene off, making it impossible for the cell to make more of the protein. The Flavr Savr tomato is an example. The enzyme that breaks down pectin in the tomato is not made which slows down ripening.

Ti plasmid based gene introduction Uses a common soil bacterium to introduce DNA into the plants.  Done by removing the disease (gall) forming genes from the plasmid and inserting the genes of interest.  Once the plasmid has been bioengineered, the bacteria transfers the genes to the plants. Process was used to develop “Honey Sweet” plums that are resistant to the virus that causes Plum Pox

The Transformation Process

Our Protocol In Brief Transform Arabidopsis thaliana flowers by dipping them in solution containing modified Agrobacterium tumefaciens (“floral dip method”) Collect seeds and sow in soil. Expose seedlings to the herbicide. Infect seedlings with pathogenic bacteria to confirm that the plant lines are resistant. Collect flower pods for possible follow up genetic studies to show that the traits are generational. (if time allows).

Floral Dip Method of Transformation 1. Only known to work on plants in the Brassicaceae Family. The most commonly used plant in research (and the one we’ll be using) is Arabidopsis thaliana. 2. Transformation Solution in a large plastic ziploc bag:  30 mL of LB (luria broth) plus the transformed Agrobacteria from your starter plate.  120 mL of 5% sucrose solution containing.03% Silwet L Mix well by gently massaging the outside of the bag. 4. Dip the flowers and stems (not the leaves) into the bag and gently agitate the bag. (You should see a film of liquid coating the plant parts.)

Floral Dip Continued 5. Label the plant with a white marker in sharpie: Period number.table number.transformed for example the group at lab station 3, fifth period would label their pots with 5.3.transformed). 6. Place pot in the designated tray. When all pots are together I will cover with a plastic cover to maintain high humidity for the first 24 hours. 7. In approximately two weeks we will cover the developing seed pods with an envelope. 8. Sow the seed and test that the new plants are resistant to infection.