ATLANTA _ Monsanto Co. said it has discovered a gene, calledcholesterol oxidase, that will broaden the ability of plants to resistpests beyond the protective capabilities of the bacillus thuringiensis(bt) gene.

Robert Fraley, president of Monsanto's new agricultural productsbusiness unit, announced the discovery here Sunday at the annualmeeting of the American Association for the Advancement ofScience.

Fraley said the cholesterol oxidase gene will be used in cotton, cornand potato plants to protect them from weevils, worms and beetles.He said researchers are still working to determine how the proteinacts to enable plants to kill the insects.

Monsanto discovered the gene in a fungus through its screening ofplants, soil and organisms for activity against pests. The bt gene isderived from a bacterium.

Fraley said cholesterol oxidase represents the first significantdiscovery of a protein with "potent and broad activity against pests"since the bt gene was found. He expects to begin field testing in twoyears. He said the cholesterol oxidase fortified plants could beavailable commercially by 2000.

Monsanto, of St. Louis, developed genetically engineered cotton,corn and potato plants in the late 1980s with the bt gene, which killsworms and beetles. Pending approval by the U.S. EnvironmentalProtection Agency, Fraley said the company expects to begin sellingthose plants next spring. No bt-modified plants are yet on the market.

Other companies, including Switzerland-based Ciba-Geigy, CalgeneCorp., of Davis, Calif., and Mycogen Corp., of San Diego, also aredeveloping insect-protected plants with the bt gene.

Fraley said Monsanto's studies indicate cholesterol oxidase iseffective against a greater variety of insects than the bt gene. Headded that the company expects to genetically modify plants withboth the bt gene and cholesterol oxidase to combine their pest-control properties. n

-- Charles Craig

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