Tracking the Genetic “Music” to the Ears of Corn

An ear of corn is the end result of flowering, ripening and other events orchestrated by thousands of plant genes. Now scientists are learning what part a given gene plays--by silencing it.

To discover--and possibly improve on--corn’s genetic “sheet music,” scientists with USDA’s Agricultural Research Service have teamed with colleagues at Pioneer Hi-Bred International, Inc., Johnston, Iowa. The company is a major developer and supplier of hybrid corn seed.

They want to discover the functions of certain corn genes recently found and cloned by researchers with ARS and the University of California at Berkeley. ARS geneticist Sarah C. Hake leads the experiment. Their research has already shown that one of the genes dictates how many flowers a corn plant forms. Rows of these tiny flowers mature to form the kernels that make up ears of corn.

The researchers work at the ARS/University of California at Berkeley-operated Plant Gene Expression Center in Albany, Calif. The investigation is being conducted under a cooperative research and development agreement between ARS and Pioneer Hi-Bred.

The Albany scientists suspect that some of the other recently cloned genes may also be key to corn's growth. Biotechnologists may be able to restructure some of these genes to boost yields or enhance tomorrow's corn plants in other ways. What they learn may help genetic engineers working on other farm and garden crops.

Pioneer’s scientists are using the company's proprietary "Trait Utility System for Corn," or TUSC, to reveal the jobs the newly discovered genes perform.

TUSC relies on a tactic called loss-of-function strategy, in which a gene is turned off in experimental plants. The turning-off is done by genes known as jumping genes or transposons. They can “land” on another gene, muffling its action and thus revealing its normal role. Loss-of-function ranks among the fastest ways to reveal what a gene does.

Scientific contact: Sarah Hake, Ph.D., USDA-ARS/University of California at Berkeley Plant Gene Expression Center, 800 Buchanan St., Albany, CA 94710, phone (510) 559-5907, fax (510) 559-5678, maizesh@nature.berkeley.edu.