The discovery of the gene and its cloning by scientists at the University of Wisconsin-Madison was reported today (July 14) in online editions of the Proceedings of the National Academy of Sciences (PNAS).
The identification of the gene, found in a species of wild potato known as Solanum bulbocastanum, holds significant potential. All of the varieties now cultivated commercially on more than 1.5 million acres in the United States are highly susceptible to potato late blight, a family of fungal pathogens that wreaks havoc in the field, turning tubers to mush and invariably killing any plant it infects.
"We think this could be very useful," says John Helgeson, a UW-Madison professor of plant pathology, a research scientist with the U.S. Department of Agriculture and a senior author of the PNAS paper. "No potato grown in the United States on any scale at all has resistance to this disease."
With the blight-resistant gene in hand, the Wisconsin team, which also includes Jiming Jiang, a UW-Madison professor of horticulture, was able to engineer plants that survived exposure to the many races of Phytophthora infestans. The insertion of a single gene, according to Jiang and Helgeson, effectively protects plants from the range of late blight pathogens.
"So far, the plants have been resistant to everything we have thrown at them," says Helgeson.
The world's most serious potato disease, late blight is best known as the cause of the Irish potato famine. Seeming to appear from nowhere in 1845, the fungus wiped out the staple crop of the densely populated island nation, causing mass starvation over five years, killing more than a million people and sparking a wave of immigration that had worldwide social consequences.