Corn Farmers May Enlist Bacteria Against Toxin

Farmers may soon plant corn seed inhabited by a beneficial bacterium that will protect the crop from a fungal toxin from the time the plants come up, an Agricultural Research Service scientist reported today at a conference in Arlington, Va. Fumonisin toxins can potentially threaten the safety of food and feed made with corn and other grains.

Bacillus subtilis bacteria live naturally--and harmlessly--in corn plants. In 1996, ARS microbiologist Charles Bacon began his research and discovered the bacteria could serve as benign "squatters" that deprive the toxin-producing fungi of space to take hold and grow. Gustafson LLC, a seed company in Plano, Texas, is interested in the ARS technology and is developing and testing a bacterial seed treatment.

Fumonisin toxin is made by Fusarium moniliforme fungi. If consumed in high amounts, the toxin can cause a fatal disease in horses, known as leukoencephalomalacia. In several countries, high levels of fumonisin in moldy corn have been suspected of causing esophageal cancer in humans.

Bacon works at ARS' Toxicology and Mycotoxin Research Unit in Athens, Ga. In his approach, called competitive exclusion, harmless B. subtilis forestalled invasion by the fungi in lab and greenhouse tests and in small field plots in Georgia and Iowa. Bacon and colleagues are also testing a species of Trichoderma fungus against F. moniliforme during late stages of crop growth and during storage.

Bacon and about 20 other scientists are sharing their fumonisin research findings this week at the International Conference on the Toxicology of Fumonisin. At the June 28- 30 conference, participants are reviewing current data and research so they can identify critical data gaps and research needs.

The conference was organized and sponsored by USDA, U.S. Food and Drug Administration, National Institute of Environmental Health Sciences, and the North American Branch of the nonprofit International Life Sciences Institute. ARS is the USDA's chief scientific agency.

Scientific contact: Charles Bacon, ARS Toxicology and Mycotoxin Research Unit , Athens, Ga., phone (706) 546-3158, fax (706) 546-3116.