es9b00692_si_002.xlsx (23.52 kB)
Water Disinfection Byproducts Increase Natural Transformation Rates of Environmental DNA in Acinetobacter baylyi ADP1
dataset
posted on 2019-05-03, 00:00 authored by David Mantilla-Calderon, Michael J. Plewa, Grégoire Michoud, Stelios Fodelianakis, Daniele Daffonchio, Pei-Ying HongThe process of natural transformation
allows for the stable uptake, integration, and functional expression
of extracellular DNA. This mechanism of horizontal gene transfer has
been widely linked to the acquisition of antibiotic resistance and
virulence factors. Here, we demonstrate that bromoacetic acid (BAA)a
regulated drinking water disinfection byproduct (DBP)can stimulate
natural transformation rates in the model organism Acinetobacter baylyi ADP1. We demonstrate that transformation
stimulation in response to BAA is concentration-dependent and is linked
to the ability of this compound to generate DNA damage via oxidative
stress. In presence of BAA, transcription of recA was upregulated 20–40% compared to the nontreated controls,
indicating that this component of the DNA damage response could be
associated with the increase in transformation. Other genes associated
with DNA translocation across the cytoplasmic membrane (i.e., pilX, comA) did not exhibit increased transcription
in the presence of BAA, indicating that the enhancement of transformation
is not associated with increased translocation rates of environmental
DNA. Overall, these results lead us to speculate that elevated recA transcription levels could lead to increased integration
rates of foreign DNA within the recipient cell during DNA repair.
Lastly, we show that an artificial DBP cocktail simulating the environmental
concentrations of five water DBP classes stimulates natural transformation
by almost 2-fold. The results of this study suggest that mutagens
like DBPs may play an important role in enhancing the fixation rates
of extracellular DNA in the environmental metagenome.