The spontaneous mutation frequencies of Prochlorococcus strains are commensurate with those of other bacteria
Article first published online: 27 SEP 2011
© 2011 Society for Applied Microbiology and Blackwell Publishing Ltd
Environmental Microbiology Reports
Volume 3, Issue 6, pages 744–749, December 2011
How to Cite
Osburne, M. S., Holmbeck, B. M., Coe, A. and Chisholm, S. W. (2011), The spontaneous mutation frequencies of Prochlorococcus strains are commensurate with those of other bacteria. Environmental Microbiology Reports, 3: 744–749. doi: 10.1111/j.1758-2229.2011.00293.x
- Issue published online: 14 NOV 2011
- Article first published online: 27 SEP 2011
- Received 19 May, 2011; accepted 2 September, 2011.
The marine cyanobacterium Prochlorococcus, the smallest and most abundant oxygenic phototroph, has an extremely streamlined genome and a high rate of protein evolution. High-light adapted strains of Prochlorococcus in particular have seemingly inadequate DNA repair systems, raising the possibility that inadequate repair may lead to high mutation rates. Prochlorococcus mutation rates have been difficult to determine, in part because traditional methods involving quantifying colonies on solid selective media are not straightforward for this organism. Here we used a liquid dilution method to measure the approximate number of antibiotic-resistant mutants in liquid cultures of Prochlorococcus strains previously unexposed to antibiotic selection. Several antibiotics for which resistance in other bacteria is known to result from a single base pair change were used. The resulting frequencies of antibiotic resistance in Prochlorococcus cultures allowed us to then estimate maximum spontaneous mutation rates, which were similar to those in organisms such as E. coli (∼5.4 × 10−7 per gene per generation). Therefore, despite the lack of some DNA repair genes, it appears unlikely that the Prochlorcoccus genomes studied here are currently being shaped by unusually high mutation rates.