May 17, 2007
Science of floral scents and colors blooming in Israel
Located at the Hebrew University's Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture in Rehovot, these greenhouses offer visitors both a delight to the senses and a trip to a futuristic world, where flowers emerge in different colors, with different scents and a whole new genetic makeup designed to enhance and improve the flower stock.
"You'll see types of flowers in our greenhouses that do not exist anywhere else in the world," said Vainstein, head of the institute. "People are stunned at what we are doing here. We have petunias, which traditionally don't have a smell, giving off such a strong perfume that it overpowers you as you walk through the greenhouse doors."
The greenhouses are only a small part of Vainstein's work, however. Back in the lab, he and other researchers on the agricultural, food and environmental quality sciences faculty have discovered how to insert the scent of flowers into different foods, how to intensify the smell of perfumes and creams and how to create a natural scent with nothing more than a petri dish.
The developments, which use the same genetic engineering techniques developed in the human genome project to enhance the shape, color and smell of flowers, have generated a great deal of interest from the chemical, food and flower industries, which are not only following developments but often actively funding the work.
Vainstein, a molecular biologist, began studying the molecular mechanism of scent compounds in flowers out of curiosity.
"Smell is a very volatile thing. he said. "Flowers smell differently at different times of the day, it depends if it's hot or cold, or whether the flower is young and old. Some plants give off strong scents, while others you have to crush before you can smell them."
Once the team isolated and deciphered the composition of genes and proteins operating in the petals of roses and carnations, they began to genetically engineer the plants to alter scent production. Roses, for example, give off a strong and lovely scent and have major volatile scent compounds, such as germacrene D. Vainstein took the gene responsible for this compound in roses and inserted it into different plant species, such as petunias and carnations.
"It's not that the petunias now smell of roses, but they do give off a much stronger scent than before," Vainstein said.
In another successful project, the researchers took a gene from a small aromatic plant that grows in California and introduced it to the carnation plant, which now produces the same aromatic compound as the California plant.
They've also discovered how to mute scent in flowers, such as gypsophlia (baby's breath) -- a flower often favored by florists in bouquets -- that have an unpleasant odor.
The possibilities for the plant breeding industry are exciting. The flower industry was worth $20.8 billion in 2006 in the United States alone, and more than $100 billion worldwide. Many flowers sold by florists today have lost their smell.
Vainstein's research promises to be able to not only regenerate the smell in flowers like roses but also to create entirely new scents in other flowers.
What interests the chemical and food industries, however, is that the researchers have also discovered a way to introduce these volatile scent compounds into other organisms, such as yeast -- which has many similarities to plants -- to create a bioreactor to product these natural compounds.
"In Bulgaria, the economy is built heavily on rose oil, which they produce from roses grown over large areas, but it's a very long and complicated process to create this oil," Vainstein said. "We can produce the same scent compounds using a yeast bioreactor, and we do it in a petri dish."
"We use a tiny amount of space," he continued. "A few shelves can hold row after row of petri dishes, and there is no disease, no worries about weather or pests and a drastic reduction in manpower costs. The value for the perfume industry is immense."
Using yeast bioreactors, flower scent compounds can also be introduced to foods, such as bread, or added to wine as it is prepared. Rose-flavored bread, perhaps, or a white wine with a hint of carnation could be possible.
Today food manufacturers often resort to using synthetic scent compounds in foods, but Vainstein's work, which has been patented, will enable them to create and use natural compounds.
"The food industry is very interested in the potential of this," Vainstein said. "Smell is not only what you smell with your nose but also what you taste. Through eating foods you also smell them. The aroma comes from inside your mouth to your nose passage."
Vainstein is working with a number of international companies based in the United States, the United Kingdom and Israel and has carried out commercial trials. He declines to give details, however, because of the competitive nature of the industries he works with.
"There are a number of experiments and pilot trials going on, and we are talking to many companies about many different possibilities, but much of this work is unpublished, and we are not allowed to talk about it," he stressed, adding that contracts are likely in the future.
Aside from scent, Vainstein's team of 14 professors and students is also making progress in color enhancement, introducing new colors to flowers that were traditionally white. The university has already developed a number of strains of carnations in colors such as cream and pale green, and work is progressing on color enhancement of roses and gypsophila.
These transgenic flowers are being developed in only three or four locations around the world, and the Hebrew University is the only research lab in the world that focuses on both scent and color. "Most labs work with only color or scent; we work with both," Vainstein said.