Fungal Spores

We're all inhaling a far greater amount and diversity of fungi floating in the air than previously thought, according to new research conducted by the Max Planck Institute for Chemistry and the University of Mainz.

The study shows that we breathe in between one and 10 fungal spores every time we inhale.

"Throughout the day, we inhale seven nanograms of fungal DNA," said Janine Froehlich from the University of Mainz. "That is the equivalent of 10,000 times the amount of information contained in the human genome."

Extensive data

"Today, we have identified over 100,000 types of fungi," she added. "According to estimates, there are probably over 1.5 million types."

Froehlich and Viviane Despres spent one year working on the project, filtering air and examining the particles. DNA analysis allowed the scientists to identify the fungal species present in the samples.

"In order to fish the different species out of the genetic soup of our samples, we used a kind of genetic fishhook," Froehlich said. "In contrast to earlier studies, we used several baits for different fungal species. By doing this, we were able to identify a significantly larger proportion of the species present."

Relevant information

Scientists are interested in the number of fungal spores in their air for three reasons, according to Ulrich Poeschel, who headed up the study at the Max Planck Institute for Chemistry.

"Firstly, we can use the spores to investigate whether ecosystems are being altered by climate change," he said. "Secondly, fungal spores play an important role as an allergy trigger, a cause of plant damage and a disease trigger in people, plants and animals."

But even more interesting is the role played by fungal spores in rainfall.

"Fungal spores and other biological particles can serve as condensation and crystallization nuclei for water drops and ice crystals, and so contribute to the creation of clouds, fog and precipitation," Poeschel said.

Closer investigation of the number and the properties of airborne fungal spores could, moreover, boost understanding of these processes in climate change.

"The interactions are so complex that we are always finding new processes and factors that we have to take into account," said Poeschl of the link between fungi, the biosphere and the climate.

Environmental implications

Fungal spores occur in great numbers in outdoor air, depending on geographic, meteorological and human factors. Generally, there are lower airborne concentrations in large towns and cities, when compared to rural and semi-rural sites.

But until now, the abundance and diversity of airborne fungi has never been fully explored, despite the obvious usefulness of the information. Fungal spores account for large proportions of air particulate matter, and influence the hydrological cycle and climate as nuclei for water droplets and ice crystals in clouds, fog and precipitation.

Moreover, some fungi are major pathogens and allergens: Many induce allergic responses in susceptible individuals, while allergens from fungal spores can be potent inducers of asthma and other respiratory conditions.

Comprehensive information on the diversity of these fungi is relevant to many areas of research such as bio-geosciences, climate and ecology, human and veterinary medicine, industrial and human hygiene, agriculture, bioengineering and security.

JP/UW/Ht/IDW

Editor: Sean Sinico