Interspecies interactions between fungi and bacteria are highly prevalent in nature and play critical roles in agriculture, biotechnology, and medicine. Studying such bacterial-fungal interactions offers crucial insights into fungal pathogenesis that can be leveraged in understanding and treating serious fungal diseases. The Rhizopus-Mycetohabitans endosymbiosis offers a unique model to study how endosymbionts contribute to fungal pathogenicity. Notably, the fungal host's sporulation depends entirely on the bacterial endosymbionts, which are translocated into the spores. However, the molecular details of how R. microsporus mediates endosymbiont-dependent sporulation, and subsequent symbiosis maintenance, remain unknown. HITCHHIKE aims to close this knowledge gap by utilizing a combination of genetic, biochemical, and infection biology technologies. We will focus on elucidating: (i) the means of intra-hyphal transport of non-motile endosymbionts; (ii) the molecular mechanisms of endosymbiont-dependent sporulation; and (iii) how endosymbionts contribute to fungal pathogenicity. This will not only elucidate the nature of host control in this clinically relevant bacterial-fungal alliance but also has the potential to serve as a roadmap to understanding how prokaryotic pathogens and symbionts interact with more complex eukaryotic hosts. In addition, HITCHHIKE will provide a foundation to better understand how asexual sporulation is regulated in the greater Mucoromycota phylum. These ecologically diverse fungi are utilized in biotechnology and industry, with applications spanning from food production to drug development. Dr Richter, an expert in bacterial endosymbionts of fungi, will conduct HITCHHIKE under the supervision of Prof Victoriano Garre, a pioneer in the molecular biology of Mucoromycota. The MSCA fellowship will qualify her as a leading expert in fungal-bacterial-host interactions, thus laying the foundation for establishing her independent research group.