Get ready for designer tomatoes! Scientists have identified a gene which they claim can change the shape of the juicy fruit -- for example, it can turn a round tomato into a long and thin one.
According to the researchers at Ohio State University, the gene, known as SUN, plays a crucial role in the elongated shape of various tomato varieties.
"Tomatoes are the model in this emerging field of fruit morphology studies. We are trying to understand what kind of genes caused the enormous increase in fruit size and variation in fruit shape as tomatoes were domesticated.
"We identified one key candidate gene that was turned on at high levels in the tomato varieties carrying the elongated fruit type, while the gene was turned off in round fruit.
"SUN doesn't tell us exactly how the fruit-shape phenotype is altered, but what we do know is that turning the gene on is very critical to result in elongated fruit," lead researcher Esther van der Knaap said.
The researchers identified SUN, which takes its name from the Sun 1642 variety where it was found, after looking at the entire collection of tomato germplasm. They noticed there were some varieties that had very elongated fruit shape.
"By genetic analysis, we narrowed down the region of the genome that controls this very elongated fruit shape, and eventually narrowed down that region to a smaller section that we could sequence to find what kind of genes were present at that location," the 'ScienceDaily' quoted Knaap as saying.
Once SUN was identified, the next step involved proving whether this gene was actually responsible for causing changes in fruit shape. To do so, the researchers conducted several plant-transformation experiments.
When the SUN gene was introduced into wild, round fruit-bearing tomato plants, they ended up producing extremely elongated fruit. When the gene was knocked out of elongated fruit-bearing plants, they were found to produce round fruit similar to the wild tomatoes.
The results of the study have been published in the 'Science' journal.
The researchers now hope to examine whether this same gene, or a gene that is closely related in sequence, control fruit morphology in other vegetables and fruit crops.
"Once we know all the genes that were selected during that process, we will be able to piece together how domestication shaped the tomato fruit -- and gain a better understanding of what controls the shape of other very diverse crops, such as peppers, cucumbers and gourds," Knaap said.