Researchers are developing pollen-free allergy geranium

Two introduced genes make balcony flower infertile and long lasting

One of more than 200 varieties of geraniums distributed today © Forest & Kim Starr / CC-by-sa 3.0
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Spanish researchers have created an optimal balcony flower for allergy sufferers: a variety of geranium without pollen. The variant developed by genetic engineering is also particularly durable. Their leaves and flowers are closer together than in the normal varieties and are said to have particularly intense colors. The new species of geranium owes these features to two genes that the scientists use to infect a bacterium into the plant cells, as reported in the journal "BMC Plant Biology".

One of these genes causes the geranium to produce more of the growth hormone cytokinin - a kind of "antiaging hormone" of the plants. This delayed the geranium's aging process and kept the leaves green longer, the researchers say. The second gene ensures that the tissues that normally produce the geranium pollen do not develop properly. Without pollen, the new geranium can not trigger allergies. But it also prevents that this genetically modified variety itself look or be spread on pollinator insects, state Vicente Moreno from the Institute of Molecular Biology and Plant Research (IBMCP) in Valencia and his colleagues.

"The geranium is one of the most popular ornamental plants worldwide, " explain the researchers. Already there are more than 200 different species. Many are bred for certain flower colors and shapes, others are also bred for their fragrance, as geraniums are also used in the perfume industry as a fragrance raw material. But breeders are looking for more ways to make these and other ornamental plants even more colorful, flowering, durable and resistant. In the opinion of Moreno and his colleagues, genetic engineering opens up valuable new opportunities here.

"The method of gene transfer makes it possible to deliberately introduce new traits into the varieties and thus promote geranium breeding, " say the scientists.

Tumor bacterium as a gene ferry

To produce the new variety of geranium, the researchers used the microorganism Agrobacterium tumefaciens as a geneva. In nature, this bacterium infects wounds and injuries to plants and causes ulcers and growths in these areas. These arise because the bacterium transfers parts of its genome to the plant cells and thereby influences the metabolism of the plants. This feature was exploited by the scientists: they incorporated two previously modified genes from other plants into the genome of the bacterium and had them introduced into a culture of geranium cells. From the thus genetically modified cells, the researchers then bred the new geranium plants. display

"The new variety has more branches and shorter stems, making them denser and more compact, " the researchers report. The leaves are a bit smaller and the flowers are compact, but very colorful. Compared with normal geraniums, the leaves also remained longer green, the plant was overall more durable. "This appearance, combined with longevity and pollen-lessness make this variety of geraniums interesting for both growers and flower buyers, " say the scientists. Whether and when the new variety comes on the market, the researchers do not provide information.

(BMC Plant Biology, 03.09.2012 - NPO)