title: A trade-off between oxidative stress resistance and DNA repair plays a role in the evolution of elevated mutation rates in bacteria.
abstract: The dominant paradigm for the evolution of mutator alleles in bacterial populations is that they spread by indirect selection for linked beneficial mutations when bacteria are poorly adapted. In this paper, we challenge the ubiquity of this paradigm by demonstrating that a clinically important stressor, hydrogen peroxide, generates direct selection for an elevated mutation rate in the pathogenic bacterium Pseudomonas aeruginosa as a consequence of a trade-off between the fidelity of DNA repair and hydrogen peroxide resistance. We demonstrate that the biochemical mechanism underlying this trade-off in the case of mutS is the elevated secretion of catalase by the mutator strain. Our results provide, to our knowledge, the first experimental evidence that direct selection can favour mutator alleles in bacterial populations, and pave the way for future studies to understand how mutation and DNA repair are linked to stress responses and how this affects the evolution of bacterial mutation rates.
authors: Department of Zoology, University of Oxford, Oxford, UK. clara.torresbarcelo@zoo.ox.ac.uk
authors: Clara
authors: C
authors: Torres-Barceló
authors: Gabriel
authors: G
authors: Cabot
authors: Antonio
authors: A
authors: Oliver
authors: Angus
authors: A
authors: Buckling
authors: R Craig
authors: RC
authors: Maclean
mesh_terms: D004260:DNA Repair; D004269:DNA, Bacterial / Q000737:chemistry / Q000378:metabolism; D024881:Drug Resistance, Bacterial; D019143:Evolution, Molecular; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D009154:Mutation; D059645:Mutation Rate; D018384:Oxidative Stress; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D006861:Hydrogen Peroxide