Plant Biology

Souped-Up Soybeans
Researcher applies genomics to create better biofuels

Those who hope to decrease America’s dependence on foreign oil look increasingly to one of Minnesota’s signature crops--soybeans--to do the job. Oil derived from soybean seeds may serve as a replacement for petroleum-based diesel fuel. Biodiesel, as it’s often called, has many things going for it: It’s renewable, it can be used in existing engines, and it produces less pollution than conventional diesel fuel. There’s only one problem: At current prices, it may cost more to make than it’s worth.

Plant biologist Sue Gibson is studying ways to make soybeans produce more oil.

Sue Gibson thinks she can do something about that. An associate professor in the Department of Plant Biology, Gibson explores how sugars guide plants as they distribute the energy and carbon they gather from sun and air throughout the plant, a process called partitioning. As a practical application of her research, she’s currently figuring out ways to coax soybeans to make more oil for biodiesel.

“We’ve been working for years on trying to
understand how plants make those types of decisions,” Gibson says. “I started thinking about how to apply what we’re learning. The work that we do is really pretty basic, but we always recognized that if you understood it, then you could potentially manipulate it in ways that would be economically useful.”

Gibson’s actual subject of study is not the soybean but Arabidopsis thaliana, a small flowering plant of the mustard family that is widely used as a model organism in plant biology—it’s the botanical equivalent of the white rat. Because its genome has been sequenced and many mutants are available, Arabidopsis provides a rich resource for exploring the function of various plants. Last year Gibson and David Somers, professor of agronomy and plant genetics, were awarded a seed grant from the University’s Initiative for Renewable Energy and the Environment (IREE) to learn more about partitioning as a first step toward improving biodiesel production. Using DNA chip technology, the two identified some 200 genes that appear to play a role in transforming signals sent by sugars into decisions about what carbon goes where.

Next, with additional support from IREE and the Georgia-based Consortium for Plant Biotechnology Research, Gibson hopes to narrow the field even more by studying partitioning in Arabidopsisstrains with mutations in the genes they identified in the pilot project.

“Based on that, we’ll pick out a handful of genes that look promising and test those in soybeans,” Gibson says. Once she has a clearer understanding of the genetic control of partitioning, Gibson says, the next step will be to manipulate it to enhance the soybean’s production of oil—and of protein, because the seeds have value as animal feed after the oil is extracted. The ultimate goal is a more economically sound alternative to conventional diesel fuel.

--Mary K. Hoff