Evolution of parasitism and mutualism between filamentous phage M13 andEscherichia coli

• DOI: 10.7717/peerj.2060
• Publication Date: 2016-05-24T08:23:23Z
• Authors: Jason W. Shapiro; Elizabeth S.C.P. ...; Paul E. Turner
• Keywords: Mutualism

Background. How host-symbiont interactions coevolve between mutualism and parasitism depends on the ecology of system genetic physiological constraints organisms involved. Theory often predicts that greater reliance horizontal transmission favors increased costs infection may result in more virulent parasites or less beneficial mutualists. We set out to understand transitions by evolving filamentous bacteriophage M13 its host Escherichia coli . Results. The effect phage bacterial fitness growth environment, initial assays revealed infected bacteria reproduce faster higher density than uninfected 96-well microplates. These data suggested is, fact, a facultative mutualist E. then allowed evolve replicated environments, which varied relative opportunity for vertical order assess evolutionary stability this mutualism. After 20 experimental passages, from treatments with both had evolved fastest rates. At same time, these no longer benefited ancestral bacteria. Conclusions. suggest positive correlation effects hosts culture negative toward genotype. results also expose flaws applying concepts virulence-transmission tradeoff hypothesis evolution. discuss context recent theory how affects mutualisms explore influence phages encoding virulence factors pathogenic