Contribution of increased mutagenesis to the evolution of pollutants-degrading indigenous bacteria

PLoS One. 2017 Aug 4;12(8):e0182484. doi: 10.1371/journal.pone.0182484. eCollection 2017.

Abstract

Bacteria can rapidly evolve mechanisms allowing them to use toxic environmental pollutants as a carbon source. In the current study we examined whether the survival and evolution of indigenous bacteria with the capacity to degrade organic pollutants could be connected with increased mutation frequency. The presence of constitutive and transient mutators was monitored among 53 pollutants-degrading indigenous bacterial strains. Only two strains expressed a moderate mutator phenotype and six were hypomutators, which implies that constitutively increased mutability has not been prevalent in the evolution of pollutants degrading bacteria. At the same time, a large proportion of the studied indigenous strains exhibited UV-irradiation-induced mutagenesis, indicating that these strains possess error-prone DNA polymerases which could elevate mutation frequency transiently under the conditions of DNA damage. A closer inspection of two Pseudomonas fluorescens strains PC20 and PC24 revealed that they harbour genes for ImuC (DnaE2) and more than one copy of genes for Pol V. Our results also revealed that availability of other nutrients in addition to aromatic pollutants in the growth environment of bacteria affects mutagenic effects of aromatic compounds. These results also implied that mutagenicity might be affected by a factor of how long bacteria have evolved to use a particular pollutant as a carbon source.

MeSH terms

  • Biodegradation, Environmental
  • DNA Damage
  • DNA-Directed DNA Polymerase / metabolism
  • Drug Resistance, Bacterial
  • Environmental Pollutants / metabolism*
  • Evolution, Molecular*
  • Mutagenesis*
  • Mutation Rate
  • Mutation*
  • Organic Chemicals / metabolism*
  • Pseudomonas fluorescens / genetics*
  • Pseudomonas fluorescens / growth & development
  • Pseudomonas fluorescens / metabolism

Substances

  • Environmental Pollutants
  • Organic Chemicals
  • DNA-Directed DNA Polymerase

Grants and funding

This work was supported by Institutional Research Funding IUT20-19 from Eesti Teadusagentuur (Estonian Research Council) to MK. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.