Genome sequences of evolved Prochlorococcus strains resistant to phages. Prochlorococcus marinus subsp. pastoris str. CCMP1986

Prochlorococcus coexists with many cyanophages in the oceans, likely aided by resistance to numerous co-occurring phages. Spontaneous resistance occurs frequently in Prochlorococcus and is often accompanied by a pleiotropic fitness cost manifested as either a reduced growth rate or enhanced infection by other phages. Here we assessed the fate of a number of phage-resistant Prochlorococcus strains, focusing on those with a high fitness cost.