August 21, 2003
Genetic engineering may give potato crops built-in resistance to the funguslike disease called blight -- the cause of the Irish potato famine more than 150 years ago.
By placing a gene from a naturally blight-resistant wild potato into a farmed variety, researchers from the University of Wisconsin-Madison and the University of California, Davis have made plants that are invulnerable to a range of blight strains.
The scientists suspected that a four-gene cluster in the wild potato species Solanum bulbocastanum was responsible for its resistance to blight. They cloned the genes and spliced one gene into each of four batches of potato plants. When they exposed these new cultivars to blight, one group stayed healthy, suggesting that the gene it received was conferring resistance. The scientists named the gene RB, for resistance from bulbocastanum.
- Scientists have known about S. bulbocastanum's resistance to blight since the 1950s.
- But of the scores of potato varieties bred around the world for frying, baking, boiling and chipping, none has been successfully crossed with S. bulbocastanum.
- Some of those varieties won't interbreed with their wild cousin, while others lose their best culinary traits when crossed with wild potato plants.
The environmental benefits of the modified plant are compelling, says lead researcher John Helgeson. "By transferring this gene from one potato to another, we can greatly reduce the reliance on pesticides."
Helgeson and his colleagues now aim to unravel how the RB gene enables potatoes to stand up to blight. If the researchers succeed, they might even open a way to circumvent the row over genetically modified foods. It might be possible, Helgeson says, to design a new antiblight pesticide based on S. bulbocastanum's natural defenses.
Source: Sorcha McDonagh, "Stout Potatoes: Armed with a new gene, spuds fend off blight," Science News, July 19, 2003.
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