"I am a biochemist, not a plant breeder: I'm not involved in the production of soybean oil or biofuel," Thelen continues, "but the price patterns are encouraging. If we scientists can use molecular genetics to boost soybeans' oil content, then maybe those who do grow and process soybeans can produce their oil more cheaply and accelerate the trend away from petroleum. That's how I see our research fitting into the bigger picture."

This big picture begins with a little bean, he explains. Soy plants accumulate oil during a phase of seed development called "seed filling," the six-week period during which the pod-encapsulated beans metabolize nutrients soaked up by the plant's roots and leaves.

At the beginning of filling, the kidney-shaped soy seeds are plump with starch and moisture -- picked at this point they become what the Japanese call edamame, a snack and salad staple prized by food aficionados. As they mature, the beans shed starch and water, shrinking as they "fill" with proteins and oils. At harvest, mature soybeans look like little yellow peas and contain a scant 15 percent moisture. The rest of their weight is devoted to around 40 percent protein, 20 percent oil, 35 percent carbohydrates and a five percent dash of ash.

The seed and pod filling stage is an important time for farmers. Any number of adverse conditions, drought and disease chief among them, can cut yields. It's also crucial for plant geneticists. Because the plant's oil and protein production occurs during the fill period, any attempt to engineer a more oil-rich soybean must begin with an understanding of how it works.

A bean's genes provide instructions, or coding, for enzymes -- the large, complex proteins that govern the chemical reactions necessary for life. In soybeans, as in all complex organisms, it is the manner in which these proteins are "expressed" within the cell that determines a plant's unique physical attributes, or phenotype: what, in other words, makes a soybean a soybean.

Here is where things get complicated. Proteins are composed of long chains of amino acids that twist and fold themselves into intricate three-dimensional structures. Within any given cell there are an extraordinary number and variety of these -- each one perfectly adapted to perform a specific metabolic task, usually in concert with other proteins. It is this immense array of structures and interactions that allows proteins to control a cell's function with great precision. But it also makes determining exactly which protein produces which effect maddeningly difficult.

"People are going into this area with some trepidation," says Thelen. "The tools they need to analyze proteins are pretty sophisticated. Not everyone really understands all of the physical chemistry that goes into studying proteins, so most [scientists] are taking a wait-and-see kind of approach. Fortunately, here at MU we're jumping in with both feet."

Published by the Office of Research.

©2006 Curators of the University of Missouri. Click here to contact the editor.