Why Tomatoes with Color Splotches are Tastier
Scientists have found that the mutations to produce tomatoes with uniform color throughout the surface usually disturb the production of a protein responsible for the development of sugar in the fruit.
Tomatoes, which are produced on commercial scale, are usually light green throughout the surface before they ripen and the tomatoes without the mutation have dark-green surface on the top. These two types are also very different in their taste. Now scientists have found that the same protein is responsible for both of the characteristics.
Scientists worked on the mutations and considered two genes in their study i.e. GLK1 and GLK2. These genes are thought to be important for producing energy from sunlight in plant leaves. GLK2 is usually active in fruit as well as in leaves but in the uniformly colored tomatoes, it is inactivated.
When scientists added GLK2 to the commercial style tomatoes, they found the same dark-green color that was due to huge amount of chloroplasts used to produce energy from sunlight. This energy gets stored as starches, which is converted to sugar upon ripening of tomatoes. This sugar accounts for the 20-30% of the sugar in tomatoes but in commercial-style tomatoes, it gets lost.
According to Ann Powell, study coauthor and a biochemist at UC Davis, this is not the only cause for the reduced flavor of the tomatoes but it contributes definitely.
Scientists have found that sugar levels were 40% higher in the engineered fruits. Moreover, certain chemicals such as carotenoids also increased significantly.
“This information about the gene responsible for the trait in wild and traditional varieties provides a strategy to recapture quality characteristics that had been unknowingly bred out of modern cultivated tomatoes,” said Powell.
“Now that we know that some of the qualities that people value in heirloom tomatoes can be made available in other types of tomatoes, farmers can have access to more varieties of tomatoes that produce well and also have desirable color and flavor traits,” she said.
This research has been published online in the journal Science this week.
Image: Left side tomatoes are tastier than the right side tomatoes due to color splotches. Image Credit: C. Nguyen and J. Giovannoni / June 29, 2012