The endless tale of endobacteria: a conversation with Paola Bonfante

January 1974: In the dark of the electron microscope room, Paola Bonfante started up and looked again at the greenish screen; she was indeed looking at a round body very similar to a bacterium. Unexpectedly, this faint body was inside the cytoplasm of a mycorrhizal symbiotic fungus, which was inside the root cells of a plant.