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July 10, 2011

Scientists Unravel Potato's Genetic Blueprint

by Steve Baragona

Genome sequence will help speed process of making new varieties

Scientists have decoded the genetic blueprint of the world's third most important food crop: the potato.

Researchers from 26 institutions around the world worked on the project to sequence, or map, the potato genome.

"I personally think it's a pretty exciting project," says biologist Robin Buell at Michigan State University, who worked on the project. "People...I guess they take potato for granted, right? Most people would be surprised to know it's the third most important crop, and the number one vegetable."

More than a billion people worldwide eat potatoes, and Buell says that number is growing as the demand for food increases. That's because potatoes provide a lot of nutritious food on less land than other staple crops, and they grow under lots of different conditions.

But they also fall victim to plenty of pests and diseases. It currently takes 15 to 20 years to create a new variety less susceptible to these problems, or with some other helpful trait. But Buell expects that time will now get shorter.

"Getting access to the genome sequence is going to help breeders go through the process of making new varieties a lot quicker. Trying to find genes that are important for disease resistance or nutrition content, it will make that process go a lot faster."

The researchers have already located thousands of potential resistance genes to study further.

They also uncovered a few clues about the plant's evolution. Potatoes are related to a number of important plants, including tomatoes, eggplants, peppers and tobacco. But Buell notes that the potato has something none of the others have.

"What we're eating is the below-ground part of the potato. It's actually a modified stem. And so the question is, how did nature come about developing an organ like this, a storage organ, essentially, for the plant."

Nature may have developed that edible storage organ, called a tuber, by modifying genes known to be present in other members of the potato family. Researchers have already mapped the full genome of one member of the family, the tomato.

"Now you can do these comparative studies," Buell says. "So, one thing that we did was, we could ask, what genes are present in potato and tomato, and then, which ones are either novel or expressed differently in potato, and is that what's responsible for the tuber?"

She says they don’t know for sure yet, but they have found several candidates, and researchers are busy studying them.