They reveal the origin of the beefsteak tomatoes.

The secret has to do with the number of stem cells in the culture of the tip of the plant, called meristem.

A team of scientists at Cold Spring Harbor Laboratory (CSHL) It has identified a set of genes that control the production of stem cells in tomato. Mutations in these genes explain the origin of the mammoth beefsteak tomatoes.

Most important yet, It is that research suggests how farmers can adjust the size of the fruit of any fruit crop. The research appears in Nature Genetics.

The Associate Professor Zachary Lippman and colleagues show the secret of tomato, and it features that it has to do with the number of stem cells in the culture of the tip of the plant, called the meristem.

In particular, team drew up an abnormal proliferation of stem cells to a natural mutation that arose for hundreds of years in a gene called CLAVATA3. The selection for this rare mutant by the growers of the plant is the reason why we have today's beefsteak tomatoes.

In plants, as animals, stem cells give rise to the diversity of types of specialized cells that form all the tissues and organs. But too many stem cells may be a problem.

In people, too many stem cells can lead to cancer. In the same way, When the stem cell production is controlled in plants, the growth becomes unbalanced and irregular, mortal survival.

The finely tuned balance of cells mother plants is controlled by genes that have opposite activities. Specifically, a gene known as wuschel promotes the formation of stem cells, While clavata genes inhibit the production of stem cells.

It is no surprise that when they mutate genes clavata, the plant produces too many stem cells in the meristem. However, in the recently enunciated experiments, the team of Lippman never before studied mutant tomato plants of which contained defective genes that encode enzymes that add sugar molecules to proteins.

How was this relevant to the plant stem cell discovery? Lippman experiments revealed that the enzymes, calls arabinosyltransfersases (ATS), Add sugar molecules called arabinoses to CLAVATA3, one of the key clavata.

The important discovery of the team lies in the change of the number of sugars attached to CLAVATA3 can change the number of stem cells. Three sugars is normal, and produces normal growth. But when one or more sugars in the CLAVATA3 key missing, the key already does not fit properly in the lock.

Then the wuschel gene sends its signal to make new cells mother. There is an abnormal growth; the fruit of the plant becomes extremely large.

Checking the range of the original beefsteak tomato, Lippman and his collaborator at the Ohio State University, they found that the secret of the beefsteak is made in the meristem.

Research shows that there is a continuum of possibilities for tomato plant growth and, in other plants, the clavata is highly conserved in evolution and exists in all plants.

By adjusting the amount of sugars in the keys clavata, and through other mutations affecting the trackwork components, Lippman and colleagues show that it is possible to put together the growth in ways that would allow breeders to customize the size of the fruit.