Dr. Paul Larsen, a professor of biochemistry at the University of California, Riverside (UCR), has focused his research on using genetic modification to enhance carbon capture in plants. Beginning his work on this project as a postdoctoral researcher at Cornell University in 1994, Dr. Larsen is continuing his research at UCR. His laboratory aims to reengineer crops to store carbon more efficiently while also increasing crop resilience to toxic environments.
His research is centered on the enzyme phosphoenolpyruvate (PEP) carboxylase, which plays a crucial role in photosynthesis by capturing carbon dioxide and converting it into organic material for crop metabolism. This enzyme is essential for carbon fixation in plants and can be modified in order to enhance carbon capture.
Larsen’s team has developed a technology which utilizes gene editing to develop mutant plants with enhanced PEP carboxylase activity, ultimately increasing carbon dioxide absorption, while producing a beneficial compound called malate, which will “bind to the aluminum” in the soil preventing it from entering the plant.
By analyzing the deoxyribonucleic acid (DNA) of Arabidopsis, the model plant for this research, Dr. Larsen and his team discovered specific amino acid changes in the PEP carboxylase enzyme that continuously activate the enzyme, rather than allowing it to switch between the active and inactive states. PEP carboxylase works as a sponge inside the plants, soaking up carbon dioxide from the atmosphere. These mutations would make this PEP carboxylase “sponge” work more effectively at capturing carbon from the air, and will allow Arabidopsis to do better than the standard variant.
Additionally, this modification increases malate production, which promotes aluminum resistance. Larsen described malate as an enzyme that “detoxifies aluminum” from the soil, allowing plants to grow and thrive in these aluminum-toxic soils, which are commonly found in regions such as South America, Southeast Asia and Africa.
The next phase of Dr. Larsen’s research focuses on expanding this technology to widely grown commercial crops, such as corn and soybeans. This phase of research aims to evaluate the real world benefits of this technology. If successful, this approach could help address food insecurity in developing countries by supporting crop growth on arable land.
Dr. Larsen’s progress has come with many challenges, including dismissal from the scientific community: “I submitted a grant, and the reviews came back, and they were personal attacks. One of the reviewers called me a ‘liar.’ Said that there was ‘no way that this was possible.’ Another reviewer said, well, ‘why didn’t nature select for these changes if they’re that important? Why are these only changes that are things that were constructed or generated in the laboratory?’”
Larsen attributes this criticism to the distinctiveness of his technique of genetic modification to improve carbon capture and plant resilience. He believes that the limited funding and consideration his lab has received is largely due to the fact that his discovery does not involve an “inducible phenotype,” or a characteristic that could be activated.
Dr. Larsen’s research on genetically modifying plants to increase carbon capture poses both benefits and the emergence of potential risks. Tools such as CRISPR, a genome-editing technology, allow for precise gene editing to become a reality without introducing foreign DNA into the plants. However, this approach does pose environmental risks such as unintended mutations in the organisms that could potentially disrupt the ecosystem by introducing diseases.
When asked about future implications of his research, Larsen explained that the lab’s vision extends beyond traditional crops, and could be used to modify turf grass to grow slower, reducing the need for lawn maintenance while increasing carbon capture.
Furthermore, these genetic modifications have the potential of capturing 10 million metric tons of carbon dioxide annually. Dr. Larsen’s research opens up a potential path towards agricultural solutions that aim to address carbon emissions, and increase food security.
