A bacterial battleground

Abstract

Symbiosis The white button mushrooms that many of us enjoy eating are subject to brown blotch disease caused by the bacterium Pseudomonas tolaasii . These bacteria are spread by means of biosurfactants, and damage is caused by a family of pore-forming cyclic lipopeptides called tolaasins. However, protective bacteria are also found on button mushrooms, and Hermenau et al. show how helper bacteria of the genus Mycetocola protect their host. Metabolic profiling, mass spectroscopy, structural characterization, and infection assays show that tolaasin is linearized by the helper bacteria. The authors also identify the enzyme responsible and show that a biosurfactant involved in pathogen spreading is also a cyclic lipopeptide that is neutralized by linearization. Understanding these protective mechanisms could allow the development of biocontrol strategies to stop spoilage. Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.2006109117 (2020).