Joanna Summers

My research more broadly is interested in the use of a bacterial model organism and genetic tools to gain insight into evolution and the origins of life. Specifically, the work we do uses the collective-level behaviour of the plant-colonising bacterium Pseudomonas fluorescens SBW25 as a model for the major transition from unicellular to multicellular life and the evolution of Darwinian individuality. Through experimental evolution we recreate a primitive multicellular life cycle in SBW25 that transitions between a collective ‘somatic body’ and individual cell ‘germ-line’ phenotypic state, with selection for this transition to come under developmental regulation. My research focus has been to characterise the genetic underpinnings of such a developmental switch, and understand how this ties in with the ability to respond to environmental cues. I am also interested in disentangling the functional effect of mutation and the environment on the complex cyclic-di-GMP signalling network that underpins this collective phenotype, and how this is all relevant to the behaviour of SBW25 in its natural environment.