Scientists find gene that protects against pot...( years later Ireland's population has ...)

Prior to the 1990s, chemical fungicides were available in the United States and effectively held the disease at bay. But new strains of the pathogen have emerged, testing the limits of the technology and requiring American farmers to treat potato fields as many as a dozen times a season at a cost of up to $250 per acre. In warmer climates such as Mexico, fields may be treated as many as 25 times a year with the costly and toxic chemicals.

"We used to be able to get by, but the new (late-blight) strain just levels things in no time at all," says Helgeson.

The gene that protects potatoes from the fungus comes from a plant that scientists believe co-evolved in Mexico alongside the late-blight pathogen. It was discovered, ironically, as a result of the emergence of a new strain of P. infestans that swept through the United States in 1994. At UW-Madison's Hancock Agricultural Research Station, the only plants to survive were the wild Mexican species and its progeny in Helgeson's test plots.

Subsequent to the 1994 outbreak, which required the development of new fungicides for agriculture, Helgeson and his colleagues began the hunt for the genes that conferred resistance on the wild Mexican cousin of the domesticated tubers familiar to consumers.

In 2000, Helgeson's lab reported narrowing the search to one of the 12 chromosomes of the wild plant. Now, with the gene identified, cloned and successfully tested in engineered varieties in the laboratory, at hand is a new technology that could save farmers hundreds of millions of dollars and benefit the environment by eliminating the application of thousands of tons of toxic chemicals.

But despite the huge economic and environmental gains that could be realized, it is unclear if the technology will be widely utilized. Because of European fears of genetically modified crops, and the control exercised over gr
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Contact: Jiming Jiang
jjiang1@wisc.edu
608-262-1878
University of Wisconsin-Madison
14-Jul-2003