The ornamental plant market prospers in all seasons. Geraniums and petunias are the best sellers in spring and summer, while nurseries mainly sell red-flowered poinsettias (Euphorbia pulcherima) in the winter. In Germany, more than 30 million poinsettias are sold every year, making it a lucrative business. However, the Central American plant of the spurge family is very sensitive to cold. In autumn, the young plants need to be grown in greenhouses at a temperature of 20° C. However, when the ambient temperatures start to get close to freezing point already as early as October, plant breeders face massive additional costs, not least because of constantly increasing energy prices.

Although classical breeding methods have successfully produced a few plant species that can be grown at slightly lower temperatures, these methods come to their natural limits in the case of poinsettias. Poinsettias are tropical plants and consequently completely lack genes that provide  effective protection against the cold. Therefore, all attempts to cross the plants are doomed to failure right from the start. "Using genetic engineering, we now hope to create plants that are able to grow and prosper at temperatures as low as 12° C," said Dr. Robert Boehm, head of research at Ornamental Bioscience GmbH based in Stuttgart. "This would make poinsettia production far more cost-effective for breeders."

In order to achieve this, certain thale cress (Arabidopsis thaliana) genes, which confer a far better resistance to the cold, are integrated into the genome of the popular poinsettia. “These genes encode transcription factors, regulatory elements that ensure that different metabolic pathways of the plant are upregulated,” explained Boehm.

The site where the new genes are inserted into the plant genome cannot be predicted; therefore, the integration of the genes happens more or less according to chance. This means that not all genetically modified plants demonstrate the sought-after properties. "Sometimes, the new genes lead to the destruction or silencing of important genetic traits, which in turn might have negative effects on the appearance or the general growth of the plant," said the biologist.

Boehm and his team of researchers therefore need to generate a large number of transgenic plants in the laboratory in order to be able to select and cross the best lines. "This process is the same as normal breeding procedures," said the botanist, adding that "the only difference being that the process is started with genetic engineering methods through the insertion of a new gene into the plant genome that might lead to the sought-after characteristics." Boehm is convinced that green genetic engineering will never displace classical plant breeding, but rather complement it in a meaningful way: "It enables us to realise goals in ornamental plant breeding that can only be achieved, if at all, with conventional methods over a much longer time, such as is the case of poinsettias."

The poinsettias’ reduced sensitivity to cold is only one of many activities the plant geneticist has been working on for the last two years or so. The joint-venture company, which also involves the German Selecta Klemm Group (a plant breeding organisation based in Stuttgart-Mühlhausen) and the American Mendel Biotechnology Incorporation, now plans to make a broader range of plants more resistant to heat and drought.

Boehm can now report huge progress in the breeding of petunias, which are popular balcony plants. “We believe that we will be able to sell a genetically modified plant in about two to three years’ time, and this plant will require up to 40 per cent less water than an unmodified one.” The researcher envisages that there will be huge demand for the plant in regions that are already facing reduced amounts of precipitation, “such as southern Europe and the Far East, but also California”. However, the new transgenic petunias would also appear to have concrete advantages for consumers in more moderate climates. “Such plants can go without being watered for a week or so,” said Boehm. “And the plants still look quite attractive.”

However, before the plant can be sold across the counter, quite a few regulatory hurdles need to be overcome. “As far as the authorities are concerned, our work is real virgin territory,” said Boehm. Although the genetically modified blue carnation variety developed by the Australian company Florigene has been been imported and sold in the EU for the last few years, “it is very likely that, in contrast to cut flowers which are put into vases for a few days and then thrown away, other criteria will apply to classical pot plants due to their longevity,” assumes Boehm.

Ornamental Bioscience’s genetically modified petunias will therefore have to prove in field trials that they are as ecologically harmless as their conventionally bred relatives. “It goes without saying that we want to be sure that our transgenic plants do not carry any risks, either for the environment or for people,” said Boehm who says at the same time that he is not worried about this particular issue, given the positive results achieved by scientists in the field of agricultural crops. “In the USA, genetically modified maize has been extensively grown for about 10 years, and all the initial reservations have proven to be unfounded.” In fact, the biologist is hoping that his unpretentious though colourful plants will help him to positively promote green genetic engineering.

Further information:

Ornamental Bioscience GmbH
Dr. Robert Boehm
Hanfäcker 10
70378 Stuttgart
E-mail: R.Boehm[at]ornamental-bioscience.com