In a paper published in Current Biology, Alberto Scarampi and his colleagues in Chris Howe's group show that cyanobacteria (photosynthetic bacteria) can rapidly develop resistance to a herbicide thanks to a pool of potentially beneficial mutations already existing at low frequencies in the bacterial population. This is a significant development in our understanding of how these ecologically important organisms, responsible for around a quarter of annual carbon dioxide fixation, can respond to environmental stresses.
The work also adds significantly to our understanding of bacterial evolution. Most studies have focused on bacteria having only one or two copies of their genome per cell. The cyanobacteria have many copies of their genome in each cell and this allows them to sustain the pool of potentially beneficial mutations.