Microbes and Molecules in Hidden Partnerships

A new study led at TU Graz in collaboration with partners in Uganda uncovers the root-associated microbes and chemical compounds of Mondia whitei, a plant highly valued in African traditional medicine for its therapeutic roots. To better understand the biology of this endagered species, we analyzed its microbiome (bacteria and fungi living in and around the roots) and how that microbiome is linked to the plant’s metabolites, by combining high-throughput sequencing with chemical analyses.

The study revealed that M. whitei roots host a diverse array of microbial species, ranging from bacterial groups such as Gammaproteobacteria and Actinobacteria to fungi including Sordariomycetes and Agaricomycetes. Importantly, these microbial communities did not assemble at random. Their composition was stongly shaped by geographic location, as well as by the presence of specific root metabolites.

Using advanced statistical modelling, we identified 86 compounds that showed significant positive and negative associations with root-associated microbes. These included well-known bioactive molecules such as scopoletin, fraxin, and benzaldehyde derivatives, recognized for their pharmacological properties.

The findings on this study highlight a broader principle: plants and their microbes communicate through chemistry. Root metabolites may act as signals, defenses, or resources that influence which microbes can establish, while microbial activity may, in turn, affect the chemical environment of the plant.

This study provides a strong foundation for future experimental work. Controlled assays introducing selected microbes or metabolites to M. whitei could provide mechanistic insights into these interactions, while genomic profiling of microbial isolates can further help identify pathways involved in metabolite biosynthesis.

For medicinal plants, such chemical–microbial dialogues are especially relevant. They may not only determine plant resilience but also influence the production of bioactive compounds that are key to their therapeutic value. Understanding these hidden partnerships has implications for the conservation of M. whitei and other medicinal species, ensuring that both their microbial and chemical contexts are preserved.

This reserach opens the door to microbiome-aware cultivation practices that combine plant chemistry and microbial partners to enhance both sustainability, resilience and medicinal quality.

Keywords: Bioactive compounds • Chemical ecology • Medicinal plants • Microbiome–metabolome interactions • Mondia whitei • Root-associated microbes

Read the research here