Jena. The bacterium Pseudomonas tolaasii triggers brown spot disease in cultivated mushrooms and thus causes considerable harvest losses. The active compound Tolaasin, which is produced by the pathogen, damages the cell membrane of the fungus and the cells die. But with some support the fungus can resist: Bacteria of the genus Mycetocola inactivate both the toxic Tolaasin as well as another active compound that makes the pathogen mobile and enables its spread. A team of researchers from Jena took a closer look at the molecular mechanism of the microbial triangle. The protective principle discovered in the process could serve as a model for applications in agriculture or medicine.