WASHINGTON (AFP) - US scientists have
discovered and cloned a gene that controls the shape of tomatoes, a find
which could help unravel the morphological mysteries of the plant
world, a study released Thursday said.
The gene known as SUN, the second ever
found to play a key role in the formation of elongated tomato varieties,
could provide vital new insight into how edible plants develop, said
Esther van der Knaap, lead researcher of the study published in the
journal Science.
Tomatoes, among the most varied crops in
terms of size and shape, evolved from a small, round ancestral wild
fruit to the many varieties grown today. But little is known about the
genetic principles for such transformations in tomatoes or other fruits
and vegetables.
“Tomatoes are the model in this emerging
field of fruit morphology studies,” said van der Knaap, an assistant
professor of horticulture and crop science at Ohio State University.
“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,” she added.
“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.”
She also said that SUN, which takes its
name from the oval shaped and pointy “SUN 1642″ tomato variety in which
the gene was found, does not show exactly how the fruit-shape phenotype
gets changed.
“But what we do know is that turning the gene on is very critical to result in elongated fruit,” she said.
The objective now, van ker Knaap said, is
to determine whether the same gene, or one closely related, controls
morphology in other fruit and vegetable crops.
The SUN gene affects fruit shape after
pollination and fertilization, whereas the only other fruit-shape gene
previously identified — known as OVATE — affects the shape of fruit
before flowering, the report said.
