Piperacillin triggers virulence factor biosynthesis via the oxidative stress response in . Author Anran Li, Bethany Okada, Paul Rosen, Mohammad Seyedsayamdost Publication Year 2021 Type Journal Article Abstract Natural products have been an important source of therapeutic agents and chemical tools. The recent realization that many natural product biosynthetic genes are silent or sparingly expressed during standard laboratory growth has prompted efforts to investigate their regulation and develop methods to induce their expression. Because it is difficult to intuit signals that induce a given biosynthetic locus, we recently implemented a forward chemical-genetic approach to identify such inducers. In the current work, we applied this approach to nine silent biosynthetic loci in the model bacterium to systematically screen for elicitors from a library of Food and Drug Administration-approved drugs. We find that β-lactams, fluoroquinolones, antifungals, and, surprisingly, calcimimetics, phenothiazine antipsychotics, and polyaromatic antidepressants are the most effective global inducers of biosynthetic genes. Investigations into the mechanism of stimulation of the silent virulence factor malleicyprol by the β-lactam piperacillin allowed us to elucidate the underlying regulatory circuits. Low-dose piperacillin causes oxidative stress, thereby inducing redox-sensing transcriptional regulators, which activate , a pathway-specific positive regulator of the malleicyprol gene cluster. Malleicyprol is thus part of the OxyR and SoxR regulons in , allowing the bacterium to initiate virulence in response to oxidative stress. Our work catalogs a diverse array of elicitors and a previously unknown regulatory input for secondary metabolism in . Keywords Gene Expression Regulation, Bacterial, Transcription, Genetic, Models, Biological, Virulence Factors, Oxidation-Reduction, Antibiosis, Biosynthetic Pathways, Burkholderia, beta-Lactams, Reactive Oxygen Species, Oxidative Stress, Secondary Metabolism, Piperacillin Journal Proc Natl Acad Sci U S A Volume 118 Issue 26 Date Published 2021 Jun 29 ISSN Number 1091-6490 DOI 10.1073/pnas.2021483118 Alternate Journal Proc Natl Acad Sci U S A PMCID PMC8256049 PMID 34172579 PubMedPubMed CentralGoogle ScholarBibTeXEndNote X3 XML