CRISPR Plants: Coming to a Store Near You
With the use of CRISPR genetic engineering technology, non-GMO, genetically manipulated plants may be a product in the near future.
Browsing the grocery aisle for “non-GMO” produce has become a common-place habit for shoppers within the last couple of years. Even alcoholic beverages and beauty products blare “Non-GMO!” on their labels (even though they are not made with genetically modified material in the first place).
However, what really is a “GMO?”
In scientific terms, a GMO (genetically modified organism), is an organism whose genome was genetically manipulated, often to display a desired characteristic (ex. increased size or increased shelf-life). A GMO possesses a small segment of DNA from a different organism that codes for the desired quality. This small segment of DNA is strategically inserted into the host DNA to create an organism with a new trait, such as a tomato with increased shelf-life.
However, the development of GMO foods has created some backlash from the public. Some consumers are uncomfortable with using genetically modified produce or products, even though there is currently no scientific evidence that these products cause harm.
Let’s Talk About CRISPR:
Researchers use CRISPR (clustered regularly interspaced short palindromic repeats) to genetically edit the DNA of different kinds of organisms. CRISPR is a biological tool that allows researchers to perform precise cuts along a strand of DNA and either replace or delete specific segments (genes). Think of CRISPR as “molecular scissors.”
These edits do not necessarily introduce foreign DNA into the original genome. However, the target cell requires the instructions to make CRISPR, which is usually provided through a small loop of bacterial DNA that carries the instructions, or genes, for CRISPR.
Once the cell has manufactured CRISPR, a unique RNA molecule guides a specialized protein (Cas9) to a specific site on the cell’s DNA. Once Cas9 identifies the site, it cuts both strands of the DNA. If these cuts interrupt a specific sequence (gene) in the DNA, this could result in an organism who has gained or lost a characteristic.
Non-GMO CRISPR Plants:
Wusheng Liu, a plant biotechnologist in the Department of Horticultural Science at North Carolina State University, designed a way to insert CRISPR into plant cells, without the need for foreign DNA. This is a significant achievement; many consumers remain uncomfortable with GMO produce and this new method allows for the same edits to occur using a non-GMO method.
So, how does it work?
Liu used a method called lipofection, a technology previously used in mammalian cells. Plant cells are protected from the environment by a rigid cell wall. Liu removed the plant cell wall, exposing the fatty cellular membrane made out of lipids. Lipofection surrounds the CRISPR machinery in a lipid bubble which fuses with the plant cells’ lipid membrane (kind of like two oil bubbles fusing to make one large bubble).
This releases CRISPR into the cells to perform the genetic edits. After a couple of days, the cell breaks down the CRISPR machinery. Throughout this process, no foreign DNA is introduced into the plant cell and CRISPR is degenerated, resulting in non-GMO plant cells.
In order to grow an actual plant from these non-GMO cells, additional plant hormones and nutrients are required.
Liu is also working on another non-GMO method that introduces CRISPR into pollen, which then fertilizes female plants. Some of the resulting offspring will possess the desired genetic edits.
This technology is the first step to producing non-GMO crops suitable for market. With CRISPR, we could see larger produce with superior taste and shelf-life in our local grocery stores in the near future. There is still much work to do, specifically in making this technology realistic for large-scale farming, however, the applications are promising.
Keywords:
GMO: “Genetically modified organism.” An organism whose genome was genetically manipulated, often to display a desired characteristic. A GMO possesses a small segment of DNA from a different organism that codes for the desired quality.
CRISPR: “Clustered regularly interspaced short palindromic repeats.” A genetic tool used to edit the genomes of numerous organisms. Derived from bacteria.
Genes: Specific sequences in DNA that code for a protein product.
Lipofection: A method used to introduce genetic material into cells.
Additional Readings:
https://phys.org/news/2020-05-crispr-non-gmo-method.html
https://www.livescience.com/58790-crispr-explained.html
FDA List of All Genetically Modified Crops