Ambrosia pollen become more aggressive due to exhaust fumes

Contact with exhaust gases changes the pollen of the Ambrosia plants
The spread of the Ambrosia plant in Germany is associated with extremely unpleasant side effects for allergy sufferers. The annual pollen season lengthens significantly and at the same time the pollen of Ambrosia have a particularly high allergenic potential. Scientists at the Helmholtz Zentrum München have now found out that exhaust fumes additionally increase the aggressiveness of ragweed pollen.

The "pollen of the ragweed (Ambrosia artemisiifolia) exhibit increased allergen levels when the plant is exposed to nitrogen dioxide-containing exhaust gases," reports the Helmholtz Zentrum München. "Ultimately, it can be expected that the already aggressive Ambrosia pollen will become even more allergenic in the future due to air pollution," explains study leader Dr. med. Ulrike Frank from the Institute of Biochemical Plant Pathology (BIOP) at the Helmholtz Zentrum München. The study results were published in the journal "Plant, Cell & Environment".

Contact with exhaust fumes makes the pollen of the ambrosia even more aggressive. (Picture: stadelpeter / fotolia.com)

Effects of exhaust gases on the protein composition
Together with researchers from the Technical University of Munich, the research network UNIKA-T and the Christine Kühne Center for Allergy Research and Education from Switzerland, BIOP scientists investigated the effects of nitrogen oxide contact on the pollen of the ambrosia plant. For this purpose, the plants were fumigated with different amounts of NO2, which is produced, for example, during the combustion of fuel. Subsequently, the researchers observed the molecular structure of the pollen. "Our data showed that the stress caused by NO2 on the plant alters the protein composition of the pollen," says lead author. Feng Zhao in the press release of Helmholtz Zentrum München. Thus, various forms of the known allergen Amb a 1 had been significantly increased. In addition, the researchers found that the pollen from the ambrosia plants under the influence of NO2 bound more strongly to specific so-called IgE antibodies from allergic persons. This is often the beginning of an allergic reaction.

Formation of a previously unknown in Ambrosia plants allergen
The scientists also noticed that the pollen fumigated plants form a previously unknown allergen. "In their investigations, the plant researchers discovered a protein, which occurred especially at elevated NO2 levels," reports the Helmholtz Zentrum München. To date, this has not been known as Ambrosia allergen and it is very similar to a protein from rubber trees, which occurs as allergen in molds and other plants. Further experiments to study the protein are currently being prepared.

Plants on highways with increased allergy potential
"After demonstrating that ambrosia growing on motorways is far more allergenic than their off-street relatives, we have now been able to provide a reason for that," concludes Ulrike Frank. So far, the situation has been unclear here because "hundreds of parameters could play a role in nature and on roads." However, the changes in the current investigations were clearly due to the contact with exhaust gases. The plant, which originally came from America, was probably introduced to Europe via bird food, and since then it has also spread increasingly as a result of climate change. "Their pollen is very aggressive and is already the leading cause of hay fever and allergies in America," the Helmholtz scientists report. Because the plant only flowers in late summer, releasing large quantities of pollen, its spread prolongs the annual suffering of many people suffering from allergies. The increased contact with exhaust gases also seems to significantly increase the allergenic potential of the ambrosia plants. (Fp)