How Viruses Are Making Gene Editing Easier and Cheaper

By Alex Tesch,
Summer 2026

In 2005, scientists discovered a unique bacterial DNA structure called CRISPR that functions as an adaptive immune system. In other words, scientists learned that bacteria can remember what viruses tried to infect them in the past. Scientists were interested in this system because of its unique ability to change viral DNA into RNA guides, meaning that if that virus tried to infect the bacteria again, the guides would stick to the virus’s DNA. These guides acted like homing devices, alerting a protein called Cas9 to the presence of viral DNA. Cas9 then acts like molecular scissors, cutting up the DNA. Usually, this ends up destroying the virus, keeping the bacteria safe.

In 2012, scientists learned how to trick the guide RNAs (also known as gRNAs) into thinking parts of its own DNA were invading viral DNA instead. This caused Cas9 to cut up small pieces of the bacteria’s DNA. When the bacteria tried to repair these cuts, it made mistakes. This led to edits in the bacterial genes, often causing the genes to mutate and stop working.

This level of specificity in gene editing was revolutionary. In the past, scientists used chemicals or radiation to change genes. However, this only created random changes. Scientists then had to look at each organism to see if that random mutation was one they wanted to study. This took a lot of time and effort. Thus, the ability to choose where a gene edit occurred instead of relying on random chance was groundbreaking.

The news of this achievement in genetic engineering quickly spread throughout academia in the United States. From the university laboratories that spearheaded the advancement of this technology to elementary schools, where students were just beginning to be introduced to the DNA that researchers aimed to eventually modify.

Five years after the announcement that CRISPR/Cas9 could be programmed, I was introduced to the basics of genetic modification in my 6th grade science class. At the time, I was only given a taste of the wide world of genetics, but I was hooked. As I learned more about DNA, genes, and the central dogma of biology, I longed to be the one behind the discoveries. That desire led me to pursue higher education, with the express intention of conducting research.

My experience in undergraduate research at the University of Arizona gave me the foundation I needed to become an REU student with the Center for Research on Programmable Plant Systems (CROPPS), where I finally had the opportunity to build upon the CRISPR system that inspired me to attend college in the first place.

Since 2012, the CRISPR/Cas9 system has become a cornerstone of genetics for its ability to change DNA with extreme precision. The CRISPR/Cas9 system has been applied to all sorts of organisms, from bacteria to fungi, and animals to plants.

But this technology isn’t perfect. One problem is that both the Cas9 protein and the gRNA need to be inside a cell at the same time for an edit to happen. This can be difficult to achieve for some plants, especially those important to agriculture, like tomatoes.

            Normally, to get the gRNA into a tomato plant, scientists have to use a different bacterium that injects the gRNA randomly into a leaf. Scientists then have to take that leaf and painstakingly grow a whole new plant from it. This process is called tissue culturing.

            Some plants are immune to tissue culturing. There are many reasons why, such as the plant having a thicker cell wall that is hard to penetrate, or not having the right receptors for the bacteria to attach to. Some plants can have the bacteria insert the gRNA, but the leaf will die before scientists can generate a new plant from it. Because of the fragile nature of the plants undergoing tissue culturing, it can take months to years and tens of thousands of dollars to create only one genetically edited plant.

            However, researchers are developing a new method that could cut the time from months to weeks and reduce the cost to only hundreds of dollars. This method, called Virus-Induced Gene Editing (also known as VIGE), uses a virus like a microscopic delivery truck. It delivers the gRNA instructions directly to the plant cells. Those plant cells then go on to become flowers. This means that the seeds from that plant will inherently have the gene edits that the scientists want. This removes the need for tissue culture.

            Experiments show that this process works in tomatoes and can target many genes at once, while tissue culture can only edit one gene at a time. But scientists are still perfecting the process. Right now, the edits can be inconsistent, meaning only some seeds end up with the changes. Researchers are currently testing ways to lower the plant’s antiviral defense to see if that boosts the tool’s efficiency.

Ultimately, the ability to easily edit tomato genes will help us quickly learn how to improve traits like fruit taste, color, and texture. It can also help us design crops that resist diseases and harsh weather, ensuring we can feed the world long into the future.

About the Author

Alex Tesch is a University of Arizona plant sciences major with a biotechnology minor, working during the summer of 2026 in the lab of Joyce Van Eck, professor at the Boyce Thompson Institute and adjunct assistant professor in the School of Integrated Plant Science, Plant Breeding and Genetics Section in the College of Agriculture and Life Sciences.