LEXINGTON, KY. — Genetically engineering crops is a slow science. It can sometimes take over a decade to modify a crop, with most of the success hinging on how well transgenes are expressed.

Transgenes, or genes that are added to a plant’s genome that are not native to the plant itself, are often silenced or repressed, making it difficult to modify a crop. In many cases, the reproductive system of the plant naturally silences transgenes, although how the plant silences the genes is unknown. With a lack of understanding of how and why transgenes become silenced, the best method to establish transgenes in a crop is to create many transgenic lines with the hope that at least one plant will express the desired traits, like pest resistance or faster growth. Even then, it’s likely that the transgene will still become silenced after several generations.

New research from the University of Kentucky might just be the key to understanding how to better genetically engineer agricultural crops. Tomo Kawashima, an associate professor in the Plant and Soil Sciences Department at the university, discovered a new gene silencing pathway that may help to one day improve transgene expression in crops.

If farmers or crop producers were able to understand how plants silence transgenes, genetic engineering could be a faster science because it would be possible to prevent gene silencing from happening.

“Seed companies will have a much more effective way of making genetically engineered crop plants or crop seeds,” Kawashima said. “So, the cost of buying seeds could be much cheaper.”

Kawashima’s discovery came from studying thale cress plants. He and his lab members study the reproductive phases of plant development from fertilization to seed development. One of his lab members is interested in understanding sperm biology or how the components of pollen contribute to the development of plant embryos. However, the team noticed that all the transgenes they were trying to express were being completely silenced and they didn’t see expression of them in their plant lines.

At first, Kawashima thought maybe the results were from human error during the experiments. But then his team noticed that the transgenes all had something in common: they were encoding for proteins that didn’t have specific localization in the cell.

“Many proteins are targeted to particular components of the cell, like the nucleus or mitochondria,” Kawashima said. “Whenever we have transgenes that are targeted to specific components in cells, they don’t have any problems expressing and we can clearly visualize them.”

If a transgene encodes for a protein that is not targeted to any specific part of the cell though, it is not expressed. In real-world practice, unexpressed transgenes mean that the plants will not express the desired traits that someone is trying to add to a plant’s genome. Instead, many more plant lines may need to be bred which could be years of work before the desired crop is created.

Kawashima said that more research is needed to understand the molecular mechanism behind how and why plants silence transgenes that don’t have specific cellular localization. His lab plans to conduct more experiments to find the gene which causes this process to happen.

“This is a long-term project,” he said, adding that it could take decades before we completely understand how to prevent gene silencing in crops. “I am very excited that we are conducting basic research that can be linked to agriculture.”

In the future, genetically engineering crops could be made much simpler from the results of Kawashima’s continuing research. If researchers can discover and understand how plants decide to silence genes, they can exploit the natural underpinnings of plant reproduction to benefit humanity by making sure desired genes are expressed. Engineering crops to be pathogen-resistant, faster growing, or hardier could take less time and less money.

“I’m very happy I am here in Kentucky,” Kawashima said. “I am working to understand the research farmers need and how to bridge the gap between researchers and farmers.”