Villain Fungus Transformed Into Hero

By Ben Hardin
August 3, 1999

A fungus that’s notorious for producing toxins in stored grains may someday be transformed to do good works such as making vitamins, rubber and drugs, Agricultural Research Service scientists reported at a meeting today.

ARS scientists at the National Center for Agricultural Utilization Research, Peoria, Ill., have applied for a patent on a method to insert multiple genes into microorganisms to produce a variety of products. For example, the researchers modified the stored grain- infesting Fusariumsporotrichioides to produce beta-carotene. Until now, genetic engineering of organisms has usually involved introducing one or two highly expressed genes.

The scientists presented their findings on the genetic transformation system today at the annual meeting of the Society for Industrial Microbiology in Arlington, Virginia.

In the case of F.sporotrichioides, ARS scientist James D. Jones and colleagues systematically synthesized and inserted multi-gene arrays, or cassettes, of genetic material called DNA into the fungus. The NCAUR scientists’ first genetically engineered versions of F.sporotrichioides produced a carotenoid called lycopene, the substance that gives red tomatoes their color. Carotenoids, used as food colorants, food supplements and livestock and fish feed additives, also include zeaxanthin and astaxanthin.

The scientists envision additional products that someday may be produced by the microbe. These include vitamin E, industrial chemicals called terpenes, biosynthetic rubber and taxol, a drug used in treatment of some malignancies.

By using the invention to introduce different gene arrays into F.sporotrichioides, several strains, each capable of producing a specific compound, could be created, according to Timothy D. Leathers, ARS project leader on new uses for ethanol coproducts. Working with just one microbial species would streamline development of technology for making a number of products.

ARS is the U.S. Department of Agriculture's chief scientific research agency.

Scientific contact: Timothy D. Leathers and James D. Jones, ARS National Center for Agricultural Utilization Research, Peoria, Ill.; phone (309) 681-6377 (Leathers) and (309) 681-6376 (Jones); fax number (309) 681-6689; leathetd@mail.ncaur.usda.gov and jonesjd@mail.ncaur.usda.gov.