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The impact of growth rate and environmental factors on mutation rates and spectra in Escherichia coli
Author(s) -
Maharjan Ram P.,
Ferenci Thomas
Publication year - 2018
Publication title -
environmental microbiology reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.229
H-Index - 69
ISSN - 1758-2229
DOI - 10.1111/1758-2229.12661
Subject(s) - escherichia coli , mutation rate , mutation , growth rate , biology , genetics , microbiology and biotechnology , chemistry , gene , mathematics , geometry
Summary Genetic variation in bacterial populations is remarkably sensitive to environmental influences, including simple, nutritional differences. Not only the rate but also the kind of mutational changes is biased by the nutritional state of bacteria. Here we investigate the mutational consequences of a universal variable for free‐living bacteria, namely the growth rate. By controlling growth in chemostats, the rate and mix of mutations was investigated for populations of Escherichia coli subject to different specific growth rates. Both aerobic and anaerobic cultures were compared with see if growth rate is a factor in the commonest respiratory conditions for E. coli . We find mutation rates are raised markedly with decreasing growth rate. Base pair substitutions and 1‐bp insertions and deletions increase with reduced growth rate, but less so in anaerobic cultures. Insertion sequence movements are particularly sensitive to growth rate, with IS 2 being optimal at intermediate growth rates whereas IS 1 and IS 150 movements are highest at the slowest tested growth rate. A comprehensive comparison of growth rate effects, as well as six other environmental factors, provides the most complete picture yet of the range of mutational signatures in bacterial genetic variation.