Strawberry genome-sequence will lead to better fruit for consumers

December 26, 2010

GAINESVILLE, Fla. — An international team of scientists led by the University of Florida and Virginia Tech is the first to publish the DNA sequence for the strawberry — a development expected to yield tastier, hardier varieties of the berry and other crops in its family.

The genome sequence, obtained by a team of 75 researchers from 38 institutions around the globe, will be published Dec. 26 in the online version of the journal Nature Genetics.

“We’ve created the strawberry parts list,” said researcher Kevin Folta, an associate professor with UF’s Institute of Food and Agricultural Sciences. “For every organism on the planet, if you’re going to try any advanced research, such as molecular-assisted breeding, a parts list is really helpful. In the old days, we had to go out and figure out what the parts were. Now we know the molecular nuts and bolts that make up the strawberry plant.”

Having that “parts list” in hand will enable strawberry breeders to bring new varieties to market faster, creating plants that can be grown with less environmental impact, better nutritional profiles and larger yields.

“All of those dividends are probably at least a decade off, but they are definitely realities on the horticultural radar screen,” said Folta, a member of the UF Genetics Institute.

Vladimir Shulaev, a University of North Texas biological sciences professor who led the project while a faculty member of the Virginia Bioinformatics Institute at Virginia Tech, said having the genome sequence means strawberry breeders can unravel — and improve upon — even a complex trait, such as fruit quality or aroma. It will also help to create fruits containing higher levels of phytochemicals with health benefits.

Janet Slovin, a plant molecular biologist with the U.S. Department of Agriculture’s Agricultural Research Service in Beltsville, Md., who was part of the research team, said scientists may be able to help growers create berries that mature earlier or later than existing varieties so that they can get their product to market when no one else can.

“That means if you’re a grower, you can extend your growing season, get a better price per flat, and use your land more—and that’s exactly what growers want,” she said.

The consortium sequenced the woodland strawberry, a wild relative of today’s cultivated strawberry varieties. From a genetic standpoint, the woodland strawberry is similar to the cultivated strawberry but less complex, making it easier for scientists to use in research.

The strawberry is part of the Rosaceae family of flowering plants that includes important agricultural and ornamental crops, such as apples, peaches, cherries, raspberries, plums, almonds and roses. Plants in the Rosaceae family share many important traits, so unveiling the woodland strawberry’s genome should mean quicker breeding advances for those crops, as well.

The research was distinctive in several ways, Folta said.

First, it had no central funding source, unlike some similar genome-sequencing projects. Scientists donated time and used parts of smaller grants, to cover costs.

Second, the consortium was open access — meaning any scientist who had an interest in the project was allowed to play a role, even those who were not experts in genome sequencing or computational biology, Folta said.

And finally, the woodland strawberry is the first plant to have its genome sequenced exclusively by a method called short-read sequencing, he said. Such advances have only been recently reported in deriving the genome sequence of animal species, such as the panda.

In short-read sequencing, small pieces of DNA are sequenced separately. Those pieces are then strung together using computer software. Folta explained it like this:

“If you had the alphabet from A to Z, and someone gave you a piece that was A-B-C, and another piece was C-D-E-F, and another piece that was E-F-G-H, you could align all those using the common letters, and eventually develop the whole alphabet.”

Strawberry is an excellent crop for scientists to use in genetic and physiological studies, Folta said, because it takes so little space to grow and is a quick-turnaround crop, unlike some others in the Rosaceae family, such as peach, which can take several years to bear fruit.

Ted Campbell, executive director of the Florida Strawberry Growers Association, called the genome-sequencing a “very significant milestone” for growers around the world — including those in Florida, where strawberries are a $338 million-a-year commodity.

Todd Mockler, an Oregon State University associate professor and member of the genome-sequencing team, said it may be a few years before the discovery is noticeable to consumers — but positive changes will come.

“For fruit crops, and strawberry in particular, it will matter to farmers and ultimately, to consumers,” he said. “It may mean better yields or pest resistance, improvements in shelf life and things like flavor, fragrance, taste and appearance. Having the genome sequence will enable all of that.”