Brown chemist finds gray mold's k...( PROVIDENCE R.I. [Brown University] ...)

PROVIDENCE, R.I. [Brown University] Gray mold is a gardener's nightmare. The fungus, also known by its scientific name Botrytis cinerea, is a scourge to more than 200 agricultural and ornamental plant species, including staples such as tomatoes, strawberries, snap and lima beans, cabbage, lettuce and endive, peas, peppers, and potatoes. Gray mold envelops its target in a velvety vise, releasing a toxin that poisons the host plants' cells, eventually causing the plant to die.

So far, the only way to eliminate the pathogen is to spray plants with fungicides, which can be costly and can contaminate the surrounding environment.

Now Brown University chemist David Cane, working with researchers in France and Spain, has figured out how the fungus's deadly toxin is made and how it might be disarmed naturally. In a paper published online in ACS Chemical Biology, the scientists have identified the set of genes that manufactures the toxin and in particular the central gene the fungus uses for this synthesis. They also have also shown that shutting off this gene by interrupting the fungus's DNA completely shuts down toxin production, removing the special weapon the mold uses to kill and invade target plant cells.

"It's a big step to being able to disarm this toxin naturally through a combination of DNA sequencing and chemistry," said Cane, the Vernon K. Krieble Professor of Chemistry and professor of biochemistry, one of three primary authors of the paper.

The researchers, led by French scientist and paper co-author Muriel Viaud, started by determining the complete DNA sequence for Botrytis cinerea. Working with Spanish organic chemist and paper co-author Isidro Collado, the scientists focused on the chemical agent botrydial that gray mold uses to overwhelm host plants.

From among the roughly 9,000 genes present in gray mold, the researchers identified a cluster of five genes that is responsible for pro
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