31 Jul 2011

Potato project aims to create spuds you’ll like

An international project based in Peru hopes that by decoding the potato’s entire genetic code, it will allow future breeders to create pest-resistant spuds.

In Peru they have been cultivating potatoes for at least 7,000 years. The Spanish first brought the spud to Europe in the 1560s and now, after rice and wheat, it has become man’s third most important source of food worldwide, writes Channel 4 News Science Correspondent Tom Clarke.

So it is fitting, then, that in times of anxiety about future food supplies, Peru is also home to the International Potato Centre. Just outside the capital Lima, CIP now holds the world’s most complete collection of wild and cultivated potatoes.

The earthquake-proof building contains vast rooms, kept at the same temperature as a household fridge, to store nearly every variety of potato, wild and cultivated.

Just outside Lima, the International Potato Centre holds the worlds most complete collection of potatoes.

There are potatoes from the high Bolivian Andes, varieties that climb like vines from the tropical forests of Mexico, and a type of desert potato that grows as far north as Arizona.

Tiny potato plants are held in suspended animation, with their roots in a test-tube of growth medium. Every two years or so they are allowed to flourish, then part of the plant is returned to the vaults in a cycle of preservation.

As a back-up, a team led by Dr David Tay, director of the International Potato Centre, freeze tissue from each potato variety in liquid nitrogen.

International collaboration

But that is not all they do. Shipping their precious potatoes worldwide, this facility has been at the heart of an international collaboration that has just revolutionized our understanding of potatoes.

Having an entire genetic map of the potato is a boon for plant breeders.

Based on their collection, researchers at CIP assembled a DNA profile of a “typical” potato. This was then sent 6,000 miles to the centre of potato research in the UK, the James Hutton Institute in Dundee. Along with 13 other research groups worldwide, the Dundee team then sequenced the entire genome of the potato.

It turns out the spud has a total of 39,000 genes – far more than a human’s 23,000, but about average for a plant. Crucially, more than 800 of those genes are linked to resistance to diseases like late blight, the devastating fungal disease that contributed to the Irish potato famine.

Others genes identified confer tolerance to frost or drought. Having an entire genetic map of the potato is a boon for plant breeders.

Complicated sex life

Potatoes have a complicated sex life. They can breed sexually by pollinating each others flowers, but also asexually, by allowing their tubers to sprout. As a result, very few spuds breed “true”. On average, it takes about 10-12 years to breed a new variety of potato.

But by combining the new genome data with the accumulated ancestry, researchers hope it could soon take as little as two years.

Having a genetic guide to improving potatoes could not come at a better time. New strains of devastating blight are on the rise in Europe, and drought possibly linked to a changing climate is ruining harvests.

With nine billion mouths needing food by the end of the century, our staple crops will have to cope with everything the future throws at them.