Deconstructing a Deadly Mold, Gene by Gene

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Deconstructing a Deadly Mold, Gene by Gene

By Peabody

October 16, 2006

Fungi: Can't live with them, can't live without them.

http://www.ars.usda.gov/is/pr/2006/061016.htm

While many of these tiny spore-producers are lauded for their

industriousness (think penicillin, yeast for leavened bread, and

mold-enhanced delicacies like Roquefort and blue cheeses), it seems

there are just as many noxious fungi out there ready to contaminate

food, houses—even the air we breathe.

And no mold is as dark a character as Aspergillus flavus, which is

why scientists with the Agricultural Research Service (ARS) and

their collaborators are scrutinizing this fungus, one gene at a time.

A. flavus can be terribly destructive. With an affinity for corn,

peanuts, cottonseed and tree nuts such as almonds and walnuts, it

can plague vast acreages of crops in the United States and threaten

food and animal feed security worldwide.

What's so dangerous about A. flavus are its deadly toxins, known

collectively as aflatoxin. These fungal poisons are the second

leading cause of aspergillosis in humans. Considered to be among the

most potent carcinogens in nature, they've also been linked to some

forms of cancer.

Because of the risks associated with aflatoxin, the Food and Drug

Administration has put safeguards in place to protect consumers. But

federal researchers—like ARS geneticist Jiujiang Yu—would like to

find ways to keep toxic fungi from occurring in the first place.

Yu, who works at the ARS Southern Regional Research Center in New

Orleans, La., was part of a team of scientists who recently

sequenced a strain of the A. flavus fungus. Along with ARS

researchers Ed Cleveland and Deepak Bhatnagar, Yu collaborated on

the project with North Carolina State University's Payne and

Nierman of The Institute for Genomic Research in Rockville,

Md.

One of the team's primary goals is to pinpoint which of the fungus'

13,000 genes regulate toxin production. They'd like to disable them

so they can rob the fungus of its poison-making machinery.

Read more about this and other food safety research in the October

2006 issue of Agricultural Research magazine.

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

research agency.