Microbes are shaped by their evolutionary history, which provides them the genomic framework to cause disease. Experimental, analytical and technological innovation enables today genomic reconstruction at unprecedented detail. The Key lab aims to uncover the genetic mechanisms and phenotypic variation that underlay emergence, transmission and adaptation of pathogens. We use a systems approach...
Metabolic complementarity is hypothesized to underpin beneficial interactions between
symbiotic organisms, allowing the partners to potentially expand their combined metabolic capabilities by offsetting metabolic deficiencies. While genome-based metabolic models offer a promising avenue to predict such complementarity in silico, empirical evidence validating these predictions remains scarce....
In animal-microbe interactions, symbiont lifestyles in the host can range from intimate intracellular environments to looser extracellular associations. For each of these lifestyles, symbiont acquisition and maintenance will likely require specific sets of adaptations and interactions between both partners. Deep-sea mussels harbor their symbiotic bacteria in or on specialized gill cells called...
The growth of Drosophila melanogaster larvae depend on nutrient-providing and pathogen-suppressing microbial symbionts; these symbionts are transferred through faecal matter deposition by egg-laying females. In different plant substrates, larvae exhibit higher developmental success in the presence of autochthonous versus allochthonous symbionts. This suggests that the capacity of symbiont...
The Mediterranean Sea, known for its high biodiversity and endemic species, has experienced significant geological events that shaped its current biological landscape. This study focuses on gutless oligochaetes, which rely entirely on symbiotic bacteria for nutrition, and explores their evolutionary path and population structure across the Mediterranean. Gutless oligochaetes and other marine...
Insects developing on ephemeral patches are always pressed by resource depletion. Host- associated microbial communities (microbiota) may alleviate this stress by interacting with the substrate and temporarily stabilizing the developmental environment. Drosophila melanogaster is breeding on patches of different rotting fruits. Due to the variability of patches, microbial symbionts need to be...
Chemosynthesis is the basis for symbioses between bacteria and animals forming rich ecosystems in the dark of the deep sea. However, chemosynthesis also fuels symbioses in shallow-water sediments. One group of such coastal chemosymbionts is a diverse genus of sulfur-oxidizing gammaproteobacteria called "Candidatus Thiosymbion". The symbiotic lifestyles of ‘Ca. Thiosymbion’ differ...
Mosquito-borne viruses have emerged as global health threats due to their rapid spread and high disease burden. These viruses share a common feature: the virus is inoculated in the host skin tissue, a tissue colonized by a complex microbial community. The early events at the skin interface are critical for virus replication, yet the role of host skin bacteria remains unclear. In this work, we...
Symbiotic relationships are an inevitable part of the existence of all living organisms. Where one may be more beneficial, the other may be very harmful, and in the life of an organism these types of interactions never occur in only one form. As sessile organisms, plants are constantly exposed to mutualistic, commensal, and parasitic interactions, often at the same time. Sweet potato (Ipomoea...
Flavobacteriales endosymbionts are well described as obligate endosymbionts of cockroaches (Blattabacterium sp.) and sveral Auchhenorhyncha (Karelsulcia muelleri). In the last years we discovered them also in several beetle families, mostly specialized to provision precursors of tryrosine. Tyrosine is a central building block of the insect cuticle and elimination or inhibition of these...
All mouthless catenulid flatworms of the genus Paracatenula are in a symbiotic relationship with the chemosynthetic bacteria Candidatus Riegeria. This ancient symbiosis has been established more than 400 MYA, the endosymbionts are strictly transmitted vertically and, based on a single symbiont genome, the symbionts still harbour all genes essential for the complete nutrition of their animal...
Spiroplasma is a gram-positive, cell wall-less, motile bacteria found in plants and animals. In Drosophila, these maternally inheritable bacteria were first found in neotropical willistoni-group samples in the 1960s with low prevalence as a sex-ratio disorder agent. Unfortunately, these strains were lost before being studied by molecular methods. Later, Spiroplasma has been found in different...
Biotrophic fungal plant pathogens co-evolve with their hosts often leading to narrow host ranges. New host specificities resulting in the emergence of novel plant diseases can arise after so-called host jumps. Resulting from a recent host jump, the biotrophic smut fungus Sporisorium reilianum exists in two distinct formae speciales, S. reilianum f.sp. reilianum (SRS) and S. reilianum f.sp....
Insect-microbe relationships are widespread, traversing a broad spectrum of reciprocal dependency, intimacy, duration, and cooperation. Many insects are only able to establish in their ecological niche because of bacterial partners. The false click beetles (Coleoptera, Throscidae) are a small, but globally distributed family that live in leaf litter and decaying wood and were previously...
Social bees, including honey bees and bumble bees, harbour a highly specialized and conserved gut microbial community. This microbiota has been implicated in beneficial roles in nutrient digestion and pathogen resistance. We are studying mechanisms by which these bacteria interact with each other, and with the host, to form a stable symbiotic community. We are using genomic, transcriptomic,...
Over ten thousand years ago, Drosophila melanogaster expanded from its sub-Saharan ancestral range to temperate regions, relying on thermotolerance mechanisms to adapt to new abiotic conditions. These mechanisms enable the fruit fly to survive fluctuating temperatures and recover from cold-induced injuries, with their effectiveness closely linked to the insect’s diet and nutritional status....
Members of the Roseobacter group (class Alphaproteobacteria) can account for up to 25% of the bacterial community in marine ecosystems. They are physiologically versatile, which can be regarded as prerequisite for an adaptation to different ecological niches. Members of the group are morphologically heterogeneous and either form rod- shaped single cells of variable length or multicellular...
The arbuscular mycorrhizal symbiosis (AMS) is a crucial partnership that enabled plants to colonize land. However, some plant lineages have evolved to abandon this symbiosis. We explored how these non-mycorrhizal plants obtain phosphorus,a nutrient typically provided by AMS. Our research discovered that these plants have formed new relationships with diverse fungi, especially those belonging...
Beneficial associations between insects and microbes are widespread, however our understanding of complex microbial communities with intricate interactions between the members and their influence on composition and functionality of symbiosis remains limited. We address symbiont-symbiont interactions in the context of a multipartite defensive symbiosis. Lagria villosa (Coleoptera:...
Microbial communities associated with plants play a crucial role in their host’s health and can influence essential physiological pathways. So far, the dynamic of microbiomes in plant populations from natural ecosystems is poorly described beyond studies in the model plant Arabidopsis thaliana. Through the study of the grass species Agrostis capillaris, we aim to explore the dynamic of...
Fungi of the subphylum Mortierellamycotina occur ubiquitously in soils where they play pivotal roles in carbon cycling, xenobiont degradation, and promoting plant growth. These important fungi are, however, threatened by micropredators such as fungivorous nematodes, and yet little is known about their protective tactics. We have found that Podila verticillata shields itself from fungivorous...
The recent advancements in metabolomics and genomic sequencing technologies have sparked a resurgence in natural product exploration, especially in ecological contexts. Analysing the intricate chemistry of symbiotic systems has become increasingly important given the significance of diverse microbial metabolites in regulating such interactions. Our recent findings highlight that symbiotic...
Symbiotic relationships between unicellular eukaryotes (protists) and endosymbiotic bacteria are widespread, unexpectedly diverse, dynamic and have been established independently many times. We explore the interactions between intracellular rickettsiae, chlamydiae, and holosporacea and diplonemids, which are extremely diverse, abundant yet understudied free- living marine flagellates. While...
The Common Symbiosis Signalling Pathway (CSSP) plays a pivotal role in orchestrating symbiotic relationships between plants and arbuscular mycorrhiza fungi, as well as between leguminuos plants and nitrogen-fixing bacteria. These symbioses are vital for optimal plant nutrient acquisition, particularly nitrogen and phosphorous. While the functions of CSSP genes in arbuscular mycorrhizal...
Host-microbe associations are essential for the health of seagrass meadows. While the seagrasses themselves host specific and benefical ‘microbiomes’, also symbionts of co-occurring animals can benefit the seagrass ecosystem, such as the sulfur-oxidizing Thiodiazotropha endosymbionts of lucinid clams that ‘detoxify’ seagrass sediments. Molecular surveys are revealing members of the genus...
Even though exact ecology and trophic mode of Umbelopsis (Mucoromycota) representatives remain elusive, these fungi are considered soil saprotrophes, often associated with plant matter. Umbelopsis fungi interact frequently with bacteria, and Paraburkholderia are among the most common symbionts. This relationship is facultative, unlike previously described Mucoromycota- Burkholderiaceae...
Reproductive synchronization between hosts and guests is a defining feature of obligatory endosymbioses. However, the evolutionary stability of synchronization remains unclear when hosts and guests battle to control resource allocation to maximize their own fitness. Here, we examine how control exerted by the host over the guest (or vice versa) affects the evolution of synchronization. We...
Leaf bacteria are critical for plant health, but little is known about how plant traits control their recruitment. Aliphatic glucosinolates (GLSs) are metabolites usually associated with defense that are present in leaves of Brassicaceae plants in genotypically-defined mixtures. Upon plant cell damage, they break down into products that deter herbivory and inhibit pathogens. We studied natural...
Bacteria of the family Cand. Midichloriaceae (Rickettsiales, Alphaproteobacteria) like Aquarickettsia spp. or Grellia spp. are common intracellular symbionts in a wide range of aquatic protists and animals, such as euglenozoans, placozoans or cnidarians. They have been detected in almost 10% of all aquatic microbiomes, but their pathogenic or beneficial roles in the associations remain...
Nutritional symbioses between chemosynthetic bacteria and animals form the base of the food web at hydrothermal vent ecosystems. Deep-sea mussels are among the most successful host groups in these ecosystems, and many species harbor sulfur-oxidizing (SOX) bacteria. We discovered that SOX symbionts in deep-sea mussels differ in their morphology: some mussels have endosymbionts, while others...
The flourishing of nutrient-providing and pathogen-suppressing microbiota is a prerequisite within the ontogenetic environment of Drosophila melanogaster fruit flies. In different plant substrates, larvae achieve higher developmental success with autochthonous vs. allochthonous microbial symbionts, vertically inherited through fecal matter deposition by egg-laying females. This indicates that...
Beetles have a hard cuticle that protects them against biotic and abiotic threats. Tyrosine is essential for cuticle synthesis but insects cannot synthesize it and must obtain it with their diet. Our study investigates the symbiotic relationship between Dinoderus porcellus and its two bacterial symbionts focusing on their contribution to the host’s cuticle development. The symbiont...
Insects frequently form symbioses with beneficial bacteria that are passed onto subsequent generations. While these heritable bacterial symbionts often play important roles in host biology, experimental approaches often are limited by an inability to independently cultivate such symbionts. Here, we demonstrate the independent cultivation of Fukatsuia symbiotica, a vertically transmitted...
The brown alga Ascophyllum nodosum and its microbiota form a dynamic functional entity named holobiont. The microbial partners play a role in seaweed health by producing bioactive compounds crucial for normal morphology and development. Ascophyllum is also an important raw material to produce plant biostimulants. However, we need more knowledge about the microbiome of Ascophyllum to understand...
Understanding symbiotic interactions between soil organisms is important to understand how edaphic ecosystems contribute to ecosystem functioning, as well as plant health and nutrition. Traditional techniques are limited in their ability to capture the spatial and temporal dynamics of these interactions. Microfluidic, or "on-a-chip", technology aims to fill this methodological gap through the...
Many insects have evolved in beneficial associations with microorganisms, among which is the supplementation of nutrients. Some grain pest beetles have successfully adapted to dry conditions due to their thick cuticles, which is attributed to their ancient endosymbiont. Among the grain pest beetles with tyrosine supplementing symbionts, Prostephanus truncatus harbors the ancient symbiont,...
Leaf-associated microbial communities are shaped by diverse factors including host species, environmental conditions, and heterogeneous microenvironments across leaf surfaces. This environmental heterogeneity results in each bacterial cell experiencing unique local conditions, driving individual behaviours that influence not only survival but also the broader community dynamics. By focusing on...
Chemical interactions enable bacteria to associate closely with organisms across all domains of life. Beyond mutualistic and pathogenic interactions, small molecules known as metabolites not only provide essential building blocks for cellular membranes but also facilitate interactions between microbes and their hosts. A major challenge in studying metabolites involved in host-microbe...
The astonishing diversity of eukaryotes results from a continuous evolution process and the emergence of functional traits. Such innovations allowed eukaryotes to adapt to all biomes and conditions on Earth and are regulated by complex genetic mechanisms. One of the key innovations that paved the way of eukaryotes diversity is their ability to establish mutualistic interactions with...
The Eurasian spruce bark beetle (Ips typographus) is currently the most economically relevant pest of Norway spruce (Picea abies). This insect associates with filamentous fungi that may help it overcome the tree’s chemical defenses. However, the involvement of other microbial partners in this pest’s ecological success is unclear. In past works, we have shown that the core fungal and bacterial...
Mosquito saliva was shown to play a key role in arbovirus transmission and pathogenesis. In this study, we explored the presence of microbiota (fungi and bacteria) in mosquito saliva and their effect on mosquito-borne virus infection in vitro. Culturable fungal and bacterial colonies were isolated and identified from saliva harvested from Aedes aegypti (lab strain mosquitoes) and Culex pipiens...
Endosymbioses can give rise to new combinations of biochemical capabilities that promote evolutionary innovation and diversification. But despite the many examples of known endosymbioses across the tree of life, their de novo emergence is rare and challenging to uncover in retrospect. Using fluidic force microscopy (FluidFM), we directly implant bacteria into the filamentous fungus Rhizopus...
