New Process Breeds Resistance to Potato, Tomato Blight

(Agricultural Research Service, USDA)

Researchers have discovered a process that offers an alternative to combating resistance to late blight, a disease of potatoes and tomatoes costing the industry £5 to £6 billion ($8.0 to $9.6 billion) a year worldwide. Late blight of potatoes and tomatoes is caused by the fungus-like pathogen Phytophthora infestans (P. infestans), and was responsible for the Irish potato famine in the mid-19th century.

Paul Birch of the University of Dundee and his team at the Scottish Crop Research Institute used a genetic analysis to identify plants for breeding that are inherently resistant to late blight infection. When introduced into cultivated varieties, says Birch, such disease resistance should be far more durable.

The team studied interactions between P. infestans and potato plants, which helped identify proteins secreted by the invading pathogen and are essential for infection. This led to a better understanding of how P.infestans gets around the potato plant’s natural defenses and thus what it takes for the plant to resist infection.

“We can actually look at a potato plant’s genetic makeup and say whether it will be sustainably resistant to late blight,” says Birch, “which is a huge step forward.”

The research was funded by the Crop Science Initiative of the Biotechnology and Biological Sciences Research Council.

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