A bonanza of spuds (Image: Arne Thaysen/iStock)

A genetically modified (GM) potato has been created that makes up to 60 per cent more protein per gram than ordinary potatoes. But even with that help spuds don’t contain much protein, so that’s not the most interesting part: in a surprise result, the GM crop also yielded more potato per hectare. This is the first time that a simple genetic modification has increased yield.

Potatoes are an increasingly popular way to increase food production in India, China and other developing countries. The tubers are mainly carbohydrate, but they also contain a little protein: a medium (150-gram) spud contains 3 grams of protein, about 6 per cent of the US recommended daily allowance. The GM variety’s extra 60 per cent raises that to 4.8 grams – nearly 10 per cent of the recommended amount.

Subra Chakraborty and colleagues at India’s Central Potato Research Institute in Shimla created the high-protein “protato” in 2003 by giving potatoes a gene from the grain amaranth, a South American plant widely eaten across the tropics, including India. The gene codes for a “storage” protein in amaranth seeds, but in the protato it was linked to a DNA code that turns on production of the storage protein in tubers.


The team has now spliced this gene into seven commercial potato varieties, and field-tested them for several seasons. This is crucial, as GM crops often behave differently in the lab and the field.

Some tubers contained almost twice as much extra protein as the prototype, with increases in several essential amino acids. Tests in rats and rabbits revealed no toxic or allergic effects. However, the plants also photosynthesised more, and produced 15 to 25 per cent more potatoes per hectare by weight – the only time this has ever been reported for a plant with just one extra gene.

Hungry millions

The UN Food and Agriculture Organization reports that 925 million people will suffer chronic hunger this year. “Despite promises that GM crops could make a significant contribution to achieving global food security,” Chakraborty and colleagues write, such crops have so far mostly been used for industry or fodder, not for boosting human nutrition. The researchers hope their potatoes will change that.

Merideth Bonierbale, head of crop improvement at the International Potato Center in Lima, Peru, says her organisation has chosen to develop potatoes with high levels of iron and zinc, because their lack is a severe problem in many countries and just a little more in potatoes could make a big difference in people’s diets. The International Potato Center’s potatoes are made without genetic modification.

Chakraborty says the team is applying to Indian regulators for permission to sell the potato. As to whether the GM spud tastes different, he says: “Our data suggests better cooking, processing quality and palatability.”

Journal reference: Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1006265107