GMOs, or genetically modified organisms, are living things (in this case, plants) whose DNA has been altered. For thousands of years we’ve altered plant DNA through traditional plant breeding to create a plant or crop with the characteristics, or traits, we desire. Since the advent of biotechnology, scientists are able to create GMOs at a faster pace and improve upon those desired traits, or add in new traits.
I make GM plants for research. There are multiple ways to modify the plant’s genetic makeup (genome), but I use one method almost exclusively, the “floral dip transformation”. It is one of the simplest methods in use. It’s a funny-sounding phrase, but it exactly describes what it is: dipping flower buds into bacteria which then genetically modifies the plant. “Transformation” is another term for modification. There are other, physical, methods of transformation, but using bacteria is a clever way to do it naturally. Regardless of method, creating a GMO is a multi-step process starting with DNA and ending with a GM plant.
Choose a trait to insert
First, the molecular biologist has to choose genes (or, DNA) for a trait to put into the plant. These traits vary from offering resistance to an insect to increased nutritional value or survival in a harsh environment. Once a trait of interest is identified, the biologist then prepares the DNA by cutting and pasting specific sequences of DNA together using enzymes to make a nice little “package” that is ready for transformation. In that process they also add a gene to that package that will help them to identify the modified seeds after the DNA transfer is over, called a marker gene.
Use a natural process to transfer the genes
This DNA containing the gene is inserted into a delivery bacteria that naturally has the ability to modify a plant’s genome. In nature, the bacteria causes lumps to grow on the branches or stems of the plant where it transfers its genes. Biologists have learned how to use this bacteria’s DNA delivery system without harming the plant.
Now that the bacteria has been equipped with our desired genes, it is grown up in a solution. Then, flower buds are dipped into that bacterial solution. This triggers the bacteria to insert the selected genes into the developing seeds in the flower bud, just like it would do in nature. These immature seeds have now been genetically modified. The plant is allowed to grow normally and the seeds are harvested.
The plant transformation process isn’t highly efficient. Most of the harvested seed will not have the selected gene. This is where marker genes come in handy. Some marker genes are herbicide resistance genes that will let the plant survive herbicide spray, some others are fluorescent protein genes that make the plant glow a certain color when viewed in certain wavelengths of light. Once the seed is sown, the resulting plants are screened for the marker genes to identify the GM plants with the desired traits out of thousands of non-GM plants. The GM plants will make more seed that will be GM, and so on, passing along the desired trait for generations for research.
Plants are highly sophisticated organisms with the natural ability to live in one place, make their own food, and protect themselves from harm. Each day, in my research, I’m helping us better understand how plants are able to do those things. I’m building upon the work of microbiologists, molecular biologists, and biochemists who discovered how to harness the bacterial DNA transfer process, improve upon it, and use it to learn about a plant’s inner workings, so we can apply that knowledge to make life better in the visible world.
Alicia Walker, born and raised in Indianapolis, Indiana, is a DePauw University graduate and a Technologist in Seeds Discovery R&D, creating GMOs for research since 2005. She is an avid fan of science and the arts and spends much of her time reading non-fiction, spinning on bikes, and spinning records.