Biosynthesis of the acetyl-CoA carboxylase-inhibiting antibiotic, andrimid in Serratia is regulated by Hfq and the LysR-type transcriptional regulator, AdmX

Environ Microbiol. 2016 Nov;18(11):3635-3650. doi: 10.1111/1462-2920.13241. Epub 2016 May 25.


Infections due to multidrug-resistant bacteria represent a major global health challenge. To combat this problem, new antibiotics are urgently needed and some plant-associated bacteria are a promising source. The rhizobacterium Serratia plymuthica A153 produces several bioactive secondary metabolites, including the anti-oomycete and antifungal haterumalide, oocydin A and the broad spectrum polyamine antibiotic, zeamine. In this study, we show that A153 produces a second broad spectrum antibiotic, andrimid. Using genome sequencing, comparative genomics and mutagenesis, we defined new genes involved in andrimid (adm) biosynthesis. Both the expression of the adm gene cluster and regulation of andrimid synthesis were investigated. The biosynthetic cluster is operonic and its expression is modulated by various environmental cues, including temperature and carbon source. Analysis of the genome context of the adm operon revealed a gene encoding a predicted LysR-type regulator, AdmX, apparently unique to Serratia strains. Mutagenesis and gene expression assays demonstrated that AdmX is a transcriptional activator of the adm gene cluster. At the post-transcriptional level, the expression of the adm cluster is positively regulated by the RNA chaperone, Hfq, in an RpoS-independent manner. Our results highlight the complexity of andrimid biosynthesis - an antibiotic with potential clinical and agricultural utility.

MeSH terms

  • Acetyl-CoA Carboxylase / antagonists & inhibitors*
  • Acetyl-CoA Carboxylase / genetics
  • Acetyl-CoA Carboxylase / metabolism
  • Anti-Bacterial Agents / metabolism*
  • Bacterial Proteins / antagonists & inhibitors
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Base Sequence
  • Gene Expression Regulation, Bacterial* / drug effects
  • Host Factor 1 Protein / genetics
  • Host Factor 1 Protein / metabolism*
  • Macrolides / metabolism
  • Multigene Family
  • Polyamines / metabolism
  • Polyenes / metabolism
  • Pyrroles / metabolism
  • Serratia / enzymology*
  • Serratia / genetics
  • Serratia / metabolism
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*


  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Host Factor 1 Protein
  • Macrolides
  • Polyamines
  • Polyenes
  • Pyrroles
  • Transcription Factors
  • zeamine
  • andrimid
  • Acetyl-CoA Carboxylase