title: Costs and benefits of natural transformation in Acinetobacter baylyi.
abstract: BACKGROUND
  Natural transformation enables acquisition of adaptive traits and drives genome evolution in prokaryotes. Yet, the selective forces responsible for the evolution and maintenance of natural transformation remain elusive since taken-up DNA has also been hypothesized to provide benefits such as nutrients or templates for DNA repair to individual cells.
  
  
  RESULTS
  We investigated the immediate effects of DNA uptake and recombination on the naturally competent bacterium Acinetobacter baylyi in both benign and genotoxic conditions. In head-to-head competition experiments between DNA uptake-proficient and -deficient strains, we observed a fitness benefit of DNA uptake independent of UV stress. This benefit was found with both homologous and heterologous DNA and was independent of recombination. Recombination with taken-up DNA reduced survival of transformed cells with increasing levels of UV-stress through interference with nucleotide excision repair, suggesting that DNA strand breaks occur during recombination attempts with taken-up DNA. Consistent with this, we show that absence of RecBCD and RecFOR recombinational DNA repair pathways strongly decrease natural transformation.
  
  
  CONCLUSIONS
  Our data show a physiological benefit of DNA uptake unrelated to recombination. In contrast, recombination during transformation is a strand break inducing process that represents a previously unrecognized cost of natural transformation.
authors.affiliation: Genomic Microbiology, Institute of Microbiology, Christian-Albrechts-University Kiel, Am Botanischen Garten 11, 24118, Kiel, Germany.|Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, P.O. Box 6050 Langnes, Tromsø, Norway.
authors.forename: Nils
authors.initials: N
authors.lastname: Hülter
authors.affiliation: Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, P.O. Box 6050 Langnes, Tromsø, Norway.
authors.forename: Vidar
authors.identifier: http://orcid.org/0000-0001-7327-6751
authors.initials: V
authors.lastname: Sørum
authors.affiliation: Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, P.O. Box 8146 Dep, 0033, Oslo, Norway.
authors.forename: Kristina
authors.initials: K
authors.lastname: Borch-Pedersen
authors.affiliation: Centre for Ecolgical and Evolutionary Synthesis, Faculty of Mathematics and Natural Sciences, University of Oslo, P.O. Box 1066 Blindern, 0316, Oslo, Norway.
authors.forename: Mikkel M
authors.initials: MM
authors.lastname: Liljegren
authors.affiliation: Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, P.O. Box 6050 Langnes, Tromsø, Norway.
authors.forename: Ane L G
authors.initials: AL
authors.lastname: Utnes
authors.affiliation: Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, P.O. Box 6050 Langnes, Tromsø, Norway.
authors.forename: Raul
authors.initials: R
authors.lastname: Primicerio
authors.affiliation: Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, P.O. Box 6050 Langnes, Tromsø, Norway. klaus.harms@spdir.net.|Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, 1350, Copenhagen K, Denmark. klaus.harms@spdir.net.
authors.forename: Klaus
authors.initials: K
authors.lastname: Harms
authors.affiliation: Department of Pharmacy, Faculty of Health Sciences, UiT The Arctic University of Norway, P.O. Box 6050 Langnes, Tromsø, Norway. paal.johnsen@uit.no.
authors.forename: Pål J
authors.initials: PJ
authors.lastname: Johnsen
mesh_terms: D000150:Acinetobacter / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D005075:Biological Evolution; D003362:Cost-Benefit Analysis; D004249:DNA Damage / Q000528:radiation effects; D004260:DNA Repair / Q000502:physiology / Q000528:radiation effects; D004269:DNA, Bacterial / Q000235:genetics / Q000528:radiation effects; D043211:Exodeoxyribonuclease V / Q000378:metabolism / Q000528:radiation effects; D017353:Gene Deletion; D022761:Gene Transfer, Horizontal / Q000235:genetics / Q000528:radiation effects; D005798:Genes, Bacterial / Q000235:genetics / Q000528:radiation effects; D008565:Membrane Proteins / Q000235:genetics / Q000528:radiation effects; D009154:Mutation / Q000235:genetics / Q000528:radiation effects; D010641:Phenotype; D011995:Recombination, Genetic / Q000528:radiation effects; D013312:Stress, Physiological; D013534:Survival; D014169:Transformation, Bacterial / Q000235:genetics* / Q000528:radiation effects*; D014466:Ultraviolet Rays / Q000009:adverse effects
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; C093815:DprA protein, bacteria; D008565:Membrane Proteins; D043211:Exodeoxyribonuclease V
keywords: Bacterial evolution; Competence; DNA repair; DprA; Horizontal gene transfer; Natural transformation