L. pneumophila deploys a self-active inhibitor for inter-Legionella competition

摘要: The bacterial pathogen Legionella pneumophila alternates between intracellular replication within host eukaryotes and extracellular residence in multi-species biofilms. To persist the state, L. must withstand competition from neighboring bacteria, including other Legionella. Here, we find that can exclude species its local environment using a secreted inhibitor: HGA (homogentisic acid), unstable, redox-active precursor molecule to pneumophila's brown-black pigment. Unexpectedly, is itself inhibited by isogenic strains. This sensitivity density-dependent secretion linked growth phase, suggesting production of - resistance this inhibitor are functionally linked. Our genetic approaches further identify lpg1681 as gene modulates susceptibility HGA. We propose behaves an unusual public good, allowing established communities locally protect against invasion low-density competitors.