From Conserved Roles to Novel Cross-kingdom Communication: A Story of Hydra

Host–microbiome interactions are increasingly recognised as one of the fundamental drivers of animal development and physiology. My research investigates the functional and compositional dynamics of host-associated microbiomes using Hydra as a powerful model system. I examine how abiotic environmental factors shape microbial community structure through field-based sampling and dissect mechanistic host–microbe interactions by experimentally simplifying the Hydra microbiome under laboratory conditions. This reductionist approach revealed that a bacterial quorum-sensing molecule strongly influence host pattern formation by modulating epithelial stem cell fate decisions. These effects are mediated by a novel Hydra protein that integrates into the highly conserved Wnt signalling pathway. Additionally, by leveraging Hydra as a basal metazoan, I explore the evolutionary origins of conserved genes such as progesterone receptor membrane component 1 (PGRMC1). Our findings suggest that PGRMC1 originally evolved to confer protection under hypoxic conditions, a function later co-opted to support tumour survival in higher organisms.