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Custom-scented flowers may be on the way

Scientists have identified genes that determine a flower's smell. Now they can create flowers with never-before-smelled scents, including roses that smell like root beer or petunias that smell like wintergreen.
Image: Tyler Jones
University of Florida horticulturist David Clark examines genetically manipulated roses in a greenhouse on the university's Gainesville campus.Tyler Jones / UF / IFAS file photo
/ Source: Discovery Channel

Root beer-scented roses could soon be available at your local florist, according to scientists from Florida who are developing newly fragrant flowers.

The research could lead to custom-designed flower fragrances and even to better-smelling, and better-tasting, fruits and vegetables.

"We are very excited about the idea of putting these flowers in front of consumers and figuring out which fragrance excites people the most," said David Clark, a scientist at the University of Florida in Gainesville developing the new flowers. "Then we can use that information to assist breeders in developing flowers that people want to smell more, or even breed fruits that smell and taste better."

The key to a flower's aroma is in its genes. Over the past 50 years plant breeders consciously selected for bigger and prettier flowers and fruits. Along the way the genes that make flowers smell nicer have been lost. Clark and his colleagues have discovered those genes, albeit by accident.

The scientists were studying petunias, trying to increase the lifespan of petals. The researchers had no particular interest in petunias as objects of beauty or symbols of desire; petunias are a model system for tomatoes, as well as potatoes, tobacco and other edible crops. One way to get more tomatoes is by pollinating more flowers.

This is not as easy as it sounds. A pollinated flower releases ethylene gas. Ethylene makes the petals fall off unpollinated flowers. If the scientists could find a gene that stopped ethylene production or ethylene detection, then the likelihood of an unpollinated flower becoming pollinated, and becoming a tomato, increases.

To find genes linked with ethylene, the Florida scientists sequenced the petunia's genome. They found the ethylene genes, but they also found an unexpected blank spot on the petunia's genetic map; 12 to 13 new genes that encoded for molecules of unknown use.

Through a variety of genetic techniques, the scientists knocked out, amplified, and otherwise tweaked each of these genes until they found their function. Those 12 to 13 genes tell the plant to produce rose oil, clove oil, wintergreen, the smell of root beer, and other chemicals that, when whiffed together, give a petunia its distinctive aroma.

These genes identified, scientists can now create flowers with never-before- smelled scents, including roses that smell like root beer or petunias that smell like wintergreen.

On Monday, the Florida scientists planted the first petunia seeds designed to smell like roses. When the flowers ripen this summer, Clark and his colleagues will hold them under the blind-folded noses of potential consumers and see if they can correctly identify the smell as petunia or rose. Other combinations of flowers and smells will be coming soon.

The research isn't just about making new and unusual fragrance combinations, say Clark and other scientists. It's about restoring flavors and smells that have been lost over the last 50 years.

"We've selected for size, shape, and color but not for more subtle but equally important things like smell and nutritional value, which is why people complain about tasteless tomatoes," said Jim Gionannoni, a scientist at the U.S. Department of Agriculture. "The volatiles that contribute to aroma are often derived from necessary nutrients. Aroma is a way to signal the nutritional value of the plant."

"It's great that we can ship a strawberry from California to the Midwest, but the flavor and fragrance of that strawberry are drastically reduced," said Ryan Warner, a scientist at Michigan State University. "People are starting to look for fruit that not only looks like a strawberry, but also tastes and smells like one."

Don't expect to start looking for superfragrant flowers and fruits in your grocery store anytime soon, however. Clark says the research is proof of concept. Years, and perhaps Food and Drug Administration approval in the case of any genetically engineered plants, are required before these blooms open their petals.

And when they do, you can expect to pay a premium for nature's fragrance; Clark estimates an extra fragrant flower will cost an extra 10 cents.

"We solved the quantity issue with the baby boomers," said Clark. "Now people are going back and asking, what about the quality?"