Adaptation of Dinoroseobacter shibae to oxidative stress and the specific role of RirA

PLoS One. 2021 Mar 29;16(3):e0248865. doi: 10.1371/journal.pone.0248865. eCollection 2021.

Abstract

Dinoroseobacter shibae living in the photic zone of marine ecosystems is frequently exposed to oxygen that forms highly reactive species. Here, we analysed the adaptation of D. shibae to different kinds of oxidative stress using a GeLC-MS/MS approach. D. shibae was grown in artificial seawater medium in the dark with succinate as sole carbon source and exposed to hydrogen peroxide, paraquat or diamide. We quantified 2580 D. shibae proteins. 75 proteins changed significantly in response to peroxide stress, while 220 and 207 proteins were differently regulated by superoxide stress and thiol stress. As expected, proteins like thioredoxin and peroxiredoxin were among these proteins. In addition, proteins involved in bacteriochlophyll biosynthesis were repressed under disulfide and superoxide stress but not under peroxide stress. In contrast, proteins associated with iron transport accumulated in response to peroxide and superoxide stress. Interestingly, the iron-responsive regulator RirA in D. shibae was downregulated by all stressors. A rirA deletion mutant showed an improved adaptation to peroxide stress suggesting that RirA dependent proteins are associated with oxidative stress resistance. Altogether, 139 proteins were upregulated in the mutant strain. Among them are proteins associated with protection and repair of DNA and proteins (e. g. ClpB, Hsp20, RecA, and a thioredoxin like protein). Strikingly, most of the proteins involved in iron metabolism such as iron binding proteins and transporters were not part of the upregulated proteins. In fact, rirA deficient cells were lacking a peroxide dependent induction of these proteins that may also contribute to a higher cell viability under these conditions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological*
  • Adenosine Triphosphate / metabolism
  • Bacterial Proteins / metabolism*
  • DNA Damage
  • DNA Replication / drug effects
  • Energy Metabolism / drug effects
  • Homeostasis
  • Iron / metabolism
  • Oxidants / toxicity
  • Oxidative Stress*
  • Peroxides / metabolism
  • Rhodobacteraceae / growth & development
  • Rhodobacteraceae / physiology*
  • Sulfhydryl Compounds / metabolism
  • Superoxides / metabolism

Substances

  • Bacterial Proteins
  • Oxidants
  • Peroxides
  • Sulfhydryl Compounds
  • Superoxides
  • Adenosine Triphosphate
  • Iron

Supplementary concepts

  • Dinoroseobacter shibae

Grants and funding

This work was supported by grants of the Deutsche Forschungsgemeinschaft TRR51 to S.E. and D.J. and INST 188/365-1 FUGG to S.E. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.