New researcher uses plants to help find health care, fossil fuel, agriculture solutions

Richard Dixon

Richard Dixon

UNT faculty member Richard Dixon is a world-renowned specialist in metabolic engineering of plants. Metabolic engineering involves working with plant genetics to make plant cells produce certain materials or substances. Dixon has spent years researching how plants can solve some of the biggest problems people face in health care, agriculture and energy. 

Dixon joined UNT's Biology Department as a Distinguished Research Professor this spring. His research focuses on using metabolic engineering to produce chemicals or alter plants in ways that can treat human conditions including Alzheimer's disease, create new biorenewable products and biofuels, and improve the quality of animal feedstock and forage crops.

"By altering genes in plants, we are able to experiment with ideas and find potential solutions scientists haven't thought of before," Dixon says. "At UNT I also plan to investigate plants that haven't been experimented with much yet, including agave, vanilla orchids and even cactus."

UNT's research clusters

Dixon also is an integral member of UNT's Signaling Mechanisms in Plants research cluster, which formed in 2008. The research group is confronting the challenge of feeding a growing population in the face of an increasing demand for sustainable, bio-based fuels and materials.

"In addition to his exceptional reputation as a plant scientist, Dr. Dixon brings to UNT a new visionary leadership in the life sciences," says Kent Chapman, Regents professor of biology and cluster coordinator.

"There are so many opportunities for biological materials to become sustainable solutions to problems we face every day. Dr. Dixon's work at UNT will help solve those problems and enrich lives."

Biofuels and bioproducts

The search for alternative, natural fuel sources has been heating up for years, and Dixon hopes to find an answer in switchgrass.

He is working with the U.S. Department of Energy on a research project investigating how to develop liquid biofuels from genetically engineered switchgrass. It's an ideal plant for creating biofuel because of its high productivity and adaptation for growth in a wide area of the Southeast and Great Plains. The challenge is that the sugars in switchgrass cell walls are less available for conversion to a liquid biofuel, like ethanol, than the sugars found in corn kernels. Dixon's group has been working to modify the chemical composition of the cell walls to make the sugars far more accessible.  

"Moving ethanol away from a corn-based system is important to lessen the strain on the world's food resources," Dixon says.

Dixon was involved with a recent plant science discovery that will help researchers develop new bioproducts from lignin, a substance in plants that makes them woody and firm. Scientists in his group recently discovered that lignin can be gentically modified in ways previously thought impossible. The researchers also discovered plants that produce two types of novel lignin naturally.

"This discovery means we have new opportunities to make materials for bioproducts, such as carbon fiber," Dixon says.

Dixon will work with UNT College of Engineering professors Nandika D'Souza and Sheldon Shi to determine what types of bioproducts can be created from the new lignins.

"Because of Dr. Dixon's discoveries, the major stumbling block for making bioproducts from lignin is removed," D'Souza says. "A linear molecule solves the problem presented by the more common network lignin which can't be used in current processing equipment easily. Fibers, coatings and solid materials that are flame retardant for aerospace and buildings are now possible. And products like converted carbon will result in naturally sourced products for which we currently use non-natural sources."

Healthier animal feedstock

The lignin discoveries also mean researchers may be able to create improved animal feedstock, a market already impacted by Dixon's research. He used metabolic engineering to increase the digestibility of alfalfa, the world's top forage crop. He and his research team, working with a corporate partner, helped create a low-lignin alfalfa, which can be more easily digested by animals.

Dixon is also working on other approaches to improve alfalfa. Traditional alfalfa used to feed dairy cows is rich in protein; while it seems like this would be an advantage for the animal, in fact, the opposite can be true. Rapid degradation and fermentation of protein in the rumen – the first stomach in a cow's digestive system - causes bloating, which can be lethal to the animal, and also can mean that much of the potentially available protein is lost before it can be absorbed into the animal's body. To create more livestock-friendly alfalfa, Dixon's group has been genetically introducing compounds called condensed tannins into alfalfa foliage. These compounds slow the rate of protein digestion in the rumen, resulting in less danger of bloating and improved nitrogen nutrition, which equates to more milk or meat production.

Grape seed extract and Alzheimer's disease

Dixon is part of a research team exploring how grape seed compounds help prevent the development or delay the progression of Alzheimer's disease in mice.

While current research shows that compounds from grape seed extract can slow the progression of the disease, scientists don't know exactly why. Dixon is working with the research team that hopes to identify what activity is happening in the brain that actually slows the disease's progression. Having that explanation will allow scientists to explain, for the first time, how the compounds are affecting the development of the disease. Interestingly, the chemicals that appear to have protective effects against Alzheimer's disease are related to the tannins that protect ruminant animals from bloat.

"My mother suffered from Alzheimer's disease in her later years, so this work is very important to me," Dixon says. "The idea that we may find an answer to this devastating disease in plants, in a natural resource, is inspiring and is why I love plant science."

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