Scientists unravel secret of pink tomato

Diners in the Far East are quite partial to a variety of sweet, pink-skinned tomatoes. Now, a researcher has revealed the secret behind this pink vegetable.

Asaph Aharoni of the Weizmann Institute's Plant Sciences department in Israel says that a mutated gene, SIMYB12, is responsible for producing these pink tomatoes.

This gene acts as a 'master switch' that regulates the activities of a whole network of other genes, controlling the amounts of yellow pigments as well as a host of other substances in the tomato.

Aharoni's research focuses on plants' thin, protective outer layers, called cuticles, which are mainly composed of fatty, wax-like substances.

In the familiar red tomato, this layer also contains large amounts of antioxidants called flavonoids forming the tomatoes' first line of defence.

Some of these flavonoids also give the tomato cuticles a bright yellow cast - the colour component that is missing in the translucent pink skins of the mutants.

Using a lab system that's unique in Israel, and one of only a few in the world, Aharoni and his team are able to rapidly and efficiently identify hundreds of active plant substances called metabolites.

A multidisciplinary approach developed over the past decade, known as metabolomics, enables them to create a comprehensive profile of all these substances in mutant plants and compare it with that of normal ones.

The research showed that the differences between pink and red tomatoes go much deeper than skin colour, says a Weizmann release.

The pink tomato also has less lycopene, a red pigment known to be a strong antioxidant that's been shown to be associated with reduced risk of cancer, heart disease and diabetes.

These findings were published in the Friday issue of Science.