Archives of Microbiology

, Volume 197, Issue 6, pp 761–772 | Cite as

Role of the cell envelope stress regulators BaeR and CpxR in control of RND-type multidrug efflux pumps and transcriptional cross talk with exopolysaccharide synthesis in Erwinia amylovora

  • Daniel Pletzer
  • Antje Stahl
  • Anna Elisabeth Oja
  • Helge WeingartEmail author
Original Paper


The purpose of this study was to identify the role of the cell envelope stress-sensing systems BaeSR and CpxARP in regulation of multidrug efflux and exopolysaccharide synthesis in Erwinia amylovora. We have previously reported that BaeR activates transcription of the RND-type efflux pumps AcrD and MdtABC. In this study, we found that a cpxR-deficient mutant was highly susceptible to β-lactams, aminoglycosides and lincomycin, whereas a baeR mutant showed no change in antimicrobial sensitivity. However, overexpression of BaeR in a mutant lacking the major RND pump AcrB increased resistance of E. amylovora to several compounds that are not substrates of AcrD or MdtABC. Furthermore, we observed that overexpression of BaeR significantly increased amylovoran production. Moreover, the expression of RND-type efflux pumps was changed in regulatory mutants of exopolysaccharide production. Our data suggest that BaeSR and CpxARP regulate additional mechanisms, beside efflux, which are responsible for antimicrobial resistance of E. amylovora.


Fire blight Transcriptional regulation Two-component system Amylovoran Levan AcrD MdtABC 



This study was supported by Jacobs University Bremen and by the MOLIFE Research Center, Jacobs University Bremen. Furthermore, we acknowledge Yvonne Braun for critical reading of the manuscript.

Supplementary material

203_2015_1109_MOESM1_ESM.pdf (72 kb)
Supplementary material 1 (PDF 71 kb)


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Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  • Daniel Pletzer
    • 1
  • Antje Stahl
    • 1
  • Anna Elisabeth Oja
    • 1
  • Helge Weingart
    • 1
    Email author
  1. 1.Department of Life Sciences and ChemistryJacobs University BremenBremenGermany

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