Study of corn genetics has implications for biofuel research

by Emma Penrod

A study looking at the genetic make-up of corn not only sheds light on how Native Americans domesticated the crop thousands of years ago, but may also assist researchers in finding more efficient means of growing crops for biofuels, according to BYU professors.

The study, which appeared in the Proceedings of the National Academy of Sciences in August, explains how two genes interact to modify the corn plant’s growth. One, called grassy tillers, determines whether or not the plant produces multiple branches at the base of the plant, and the second determines how the plant reacts when it senses it is growing in direct sunlight.

Under normal circumstances, corn’s wild ancestor, known as teosinte, would grow many lateral branches, forming a short, bushy plant in direct sunlight, and focusing more energy on growing taller while producing fewer lateral branches when the plant senses it is growing in the shade. But domesticated corn invests all its energy into a single dominant stalk, even in direct sunlight. The two corn variations were so different, according to Clinton Whipple, an associate professor in BYU’s College of Life Sciences and one of the study’s co-authors, the two plants had researchers looking for corn’s wild ancestors for years.

“It’s such a dramatic difference that for years we didn’t realize teosinte was the wild counterpart of corn,” Whipple said. “But it is — they’re completely the same species.”

Whipple came across several corn mutants that produced tillers, multiple branches at the plant’s base, while studying mutations in flowers as a graduate student. He later collaborated with other researchers at the University of Wisconsin, Cornell University and Cold Spring Harbor Laboratory and began studying the mutant corn plants for a post-doctoral project. Together, the team identified the genes responsible for the change, and then analyzed the genetic make up of teosinte to determine that the grassy tillers gene was one the Native Americans had unknowingly selected for when the domesticated the species.

But Whipple said he suspects corn plants that grow additional tillers could be used by those researching biofuel production. Though plants that grow numerous branches tend to produce ears of corn too small to be used as food, the plants do produce more plant mass, which is much more interesting to biofuel researchers than ears of corn.

Chemical engineering chair Randy Lewis, who has done research on biofuels in the past, agreed the finding could impact future research into biofuel production.

“It’s exciting to see something where you would have more cellulosic materials for the making of biofuels,” Lewis said. “Cellulosic materials are being looked at very rigorously as a source for biofuels.”

However, Lewis also said altering a plant’s growth is not a fix-all solution for biofuels. Other issues, including the economic, social and environmental impacts of growing a staple food source for fuel purposes, must also be considered.

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