ChrASO, the chromate efflux pump of Shewanella oneidensis, improves chromate survival and reduction

PLoS One. 2017 Nov 22;12(11):e0188516. doi: 10.1371/journal.pone.0188516. eCollection 2017.

Abstract

The chromate efflux pump encoding gene chrASO was identified on the chromosome of Shewanella oneidensis MR1. Although chrASO is expressed without chromate, its expression level increases when Cr(VI) is added. When deleted, the resulting mutant ΔchrASO exhibits a chromate sensitive phenotype compared to that of the wild-type strain. Interestingly, heterologous expression of chrASO in E. coli confers resistance to high chromate concentration. Moreover, expression of chrASO in S. oneidensis and E. coli significantly improves Cr(VI) reduction. This effect could result either from extracytoplasmic chromate reduction or from a better cell survival leading to enhanced Cr(VI) reduction.

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Chromates / pharmacology*
  • Chromosomes, Bacterial / metabolism
  • Escherichia coli
  • Gene Expression Regulation, Bacterial / drug effects
  • Genes, Bacterial
  • Microbial Viability / drug effects*
  • Oxidation-Reduction / drug effects
  • Phylogeny
  • Shewanella / drug effects
  • Shewanella / genetics
  • Shewanella / metabolism*

Substances

  • Bacterial Proteins
  • Chromates

Grants and funding

The authors acknowledge funding by the Centre National de la Recherche Scientifique (www.cnrs.fr), Aix-Marseille Université (www.univ-amu.fr) and HTS-BIO (www.htsbio.com, Grant N°152 660). H.B. was supported by Université de Constantine 1. A.B. was supported by a MESR fellowship. C.G. was supported by the Conseil Général PACA (www.regionpaca.fr). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.