Our research combines the fields of evolutionary ecology, molecular microbiology, and genomics to address fundamental questions on how antagonistic (parasitic) and beneficial (mutualistic) microbial symbionts shape host ecology and evolution, how partners complement each other metabolically, and how host-symbiont associations defend themselves against exploitation. Although fundamental in nature, our work encompasses components of applied significance, such as the natural use of antibiotics, antibiotic resistance in parasites, and plant decomposition enzymes.

A fungus-farming termite colony consists of full siblings and each colony rears a single clone of fungus crop – conditions of high relatedness that are generally recognized to increase vulnerability to infections. However, this mutualism has an astounding ability to remain free from infections diseases. The association is highly successful and sustainable: it evolved ca. 30MYA and has radiated into more than 330 extant termite species that often dominate terrestrial ecosystems in the Old World (sub)tropics. Virulent diseases affect other advanced eusocial insects, such as honeybees, bumblebees, and the independently evolved Neotropical fungus-farming ants. In this programme, we are characterising the presence and importance of a key set of - likely complementary - lines of defence that collective appear to allow the termites to avoid diseases.

Fungus-farming termites are a paramount example of symbiotic association between an insect host, a basidiomycete fungus (genus Termitomyces) maintained as a crop in external gardens, and co-diversified gut microbial communities. Efficient biomass decomposition involves intricate steps across space (different locations within colonies) and time (different stages of biomass break down), including complementary enzyme contributions from all partners in the symbiosis. We investigate what enzymes are expressed and what plant components are decomposed through time and space to shed light on how the symbiosis has optimally secured complete biomass decomposition through natural selection and coevolution over millions of years of associations between insect hosts and microbial communities.

The application of antimicrobial compounds produced by hosts or defensive symbionts to counter the effects of diseases has been identified in a number of organisms, but despite extensive studies on their presence, we know essentially nothing about why these antimicrobials do not always trigger the rampant evolution of resistance in target parasites. Fungus-farming termites have evolved a sophisticated agricultural symbiosis that pre-dates human farming by 30 million years and, in stark contrast to virtually any other organism, does not suffer from specialised diseases. To explore how this is possible, we are developing this farming symbiosis as a model to test concepts that may account for the evasion of resistance evolution.

Adaptations to abiotic and biotic conditions through natural selection is a cornerstone in the evolution of life, but our understanding of adaptations to harsh conditions in fungi remains sparse. This is especially so for the basidiomycetes, despite their importance in natural ecosystems and for humans. The genus Podaxis is a promising model to elucidate basidiomycete adaptations to harsh environments, because species in this genus have evolved solutions to extreme abiotic and biotic conditions: desert species survive extreme drought and species growing from termite nests avoid severe antagonism from the insects during exploitation of termite resources. We are a complementary international group that propose comparative genomics, characterisations of genes of adaptive importance, and identification of putative insecticides in Podaxis. Our findings will be of fundamental importance to understand fungal adaptations and carry potential to uncover novel antibiotic compounds.

This program started in 2008 with a special grant from the Danish National Research Foundation to Koos Boomsma to initiate evolution-inspired public health research. Research focuses on questions emanating from evolutionary insights in male-female and parent-offspring conflict and uses the national public health data bases of Denmark to test hypothesis on pregnancy induced hypertension, birth size variation predicting later risks of mental disease, the impact of in vitro fertilisation on later-in-life health, and long-term effects of antibiotics prescriptions.

Our understanding of the role and impact of gut microbes in associations with hosts have seen an incredible surge with the advent of high-throughput sequencing analyses. Nevertheless, despite knowing that gut bacteria are essential for the breakdown of dietary components and for supplementing sub-optimal diets of hosts, our understanding of the link between gut microbiota composition and diet is lacking for many organisms. We apply state-of-the-art approaches to shed light on gut microbial assemblies associated with shifts in dietary regimes in cockroaches, termites, Passerine birds and some mammals. In doing so, our work contributes to providing insights into associations between gut microbial communities and diets in generally understudied animal groups, of fundamental general importance for our understanding of the factors that drive gut community assemblies.

• Professor Duur Aanen, Wageningen University, Wageningen, Holland.
• Professor Jacobus J. Boomsma, University of Copenhagen, Copenhagen, Denmark.
• Professor Andreas Brune, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.
• Assistant Professor Christine Beemelmanns, International Leibniz Research School for Microbial and Biomolecular Interactions, Jena, Germany.
• Professor Jon Clardy, Harvard Medical School, Boston, MA, USA.
• Professor Cameron Currie, University of Wisconsin-Madison, Madison, WI, USA.
• Associate Professor Z. Wilhelm de Beer, University of Pretoria, Pretoria, South Africa.
• Dr. N’golo Kone, Abidjan University, Ivory Coast.
• Professor Judith Korb, University of Freiburg, Freiburg, Germany.
• Professor Lene Lange, Aalborg University, Copenhagen, Denmark.
• Professor Dino McMahon, Freie Universität Berlin, Berlin, Germany.
• Associate Professor Dong-Chan Oh, Seoul National University, Seoul, Republic of Korea.
• Professor Søren J. Sørensen, University of Copenhagen, Copenhagen, Denmark.
• Associate Professor Garret Suen, University of Wisconsin-Madison, Madison, WI, USA.
• Professor Stephanus Venter, University of Pretoria, Pretoria, South Africa.
• Professor Mike Wingfield, University of Pretoria, Pretoria, South Africa.
• Professor Guojie Zhang, BGI Shenzhen, China and University of Copenhagen, Copenhagen, Denmark.