Studying Plants at Molecular Level May Lead to Better Biofuels

Young-Jin Lee, a faculty scientist, is seen here in the lab at the Department of Energy’s Ames Laboratory in Iowa.

Washington — Scientists at the U.S. Department of Energy’s Ames Laboratory are adapting tools used in chemistry and medicine to better understand small molecules that are the building blocks for plant biological processes.

Learning more about the minute mechanisms of plant biology will “open up new realms of study, ones that might have long-ranging implications for biofuels research and crop genetics,” according to an August 9 news release from the Ames Laboratory.

Ames’ scientists are pioneering methods to apply mass spectrometry to plant tissue, allowing a closer view of molecules at work inside plant tissue than scientists have ever had.

Mass spectrometry is a technique most often associated with analytical chemistry. It is a method of measuring atoms and molecules to determine their molecular weight, which gives greater insight into the nature of the material under study.

With origins in the late 19th century, the technique — known as matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) — has been adapted by medical and pharmaceutical fields for the last decade or so.

“In the medical field, researchers were using this type of spectrometry to map proteins in human cancers and visualize the distribution of drugs through tissues,” said Young-Jin Lee, a faculty scientist at Ames. “But in recent years, the scientific community began to look at MALDI-MS as a possibility for mapping metabolites in plant material.”

Metabolites are organic compounds used and created by the process of metabolism that happens in every cell of living organisms. Previous methods of study that plant scientists have used at this level have allowed them to learn what plant metabolites are doing in the cells, and how they are doing it, but not where.

“Before these advances, in order to analyze plant material, biologists were forced to crush up tissue,” said Basil Nikolau, the Ames faculty scientist heading the project. “We would lose spatial information — where these metabolites were located in different types of plant cells,” Nikolau said.

“With this technique, we can see the distribution of these metabolites in the plant tissue at the single cell level,” Lee said. The imaging technique can map molecule location inside a plant cell to a width that is one quarter the size of a human hair.

Working with a group of German scientists, Lee’s group studied cottonseeds, a crop that has a possible future as a source of biofuel. Its oil is also used in the food industry.

If plants are to be used as an energy source on a wide scale, then greater understanding of how carbon functions inside the cells is necessary, Nikolau said. “If you’re going to make biorenewable chemicals, the carbon comes in through photosynthesis, through plants. That process happens in discrete compartments within the organism, within individual cells. Science needs to know that highly detailed spatial information to take full advantage of it.”

The findings are published in The Plant Cell, a research publication in the field, and in The Plant Journal.