Potato, Interrupted: Genetic Engineering for Disease Resistance

Almost every cultivated variety of potato is susceptible to late blight, except a genetically engineered variety developed in the late 2000s.


| Summer 2017



Potatoes

Late blight, caused by Phytophthora infestans, can attack nearly all commercially grown potatoes.

Photo by Flickr/johnnyjet

Americans love their potatoes. We enjoy them baked and mashed, and as chips and fries, to the tune of 140 pounds per person per year. Potatoes anchor our holiday meals, our summer picnics, and our fast food indulgences. They are savory perfection.

In most ways, at least.

The potato has an Achilles’ heel. Most of our commercial varieties need help standing up to pests and pathogens, including late blight, the fungal disease that caused Ireland’s potato famine in the mid-1800s.

“Every variety in this country, almost every one of them, is susceptible [to late blight],” explains Jiming Jiang, a UW–Madison professor of horticulture. This includes Atlantic, Red Norland, Yukon Gold, and Russet Burbank of McDonald’s french fry fame.

To protect their crops from late blight, U.S. farmers spray around $77 million worth of fungicides each year. Even so, the disease takes a toll, causing some $210 million worth of crop losses annually. What if there was a better way? Globally, hardier potatoes could prevent thousands of tons of chemicals from being applied to the earth each year.

As it turns out, a hardier potato does exist. Back in the mid-2000s, Jiang and colleagues developed a series of potatoes that could survive late blight without sprays. But the improved plants never made it to the commercial market  —  they were made using genetic
engineering (GE), and at that point, no GE vegetables had yet been approved. And public opinion wasn’t favorable. It still isn’t.