Bacterial solutions to multicellularity: a tale of biofilms, filaments and fruiting bodies

Bacterial multicellularity takes several phenotypically diverse forms and has independently evolved in different species.Simple bacterial multicellularity can rapidly evolve as a result of mutations that prevent cells from separating after division or that cause independent cells to co-aggregate.Hallmark features of bacterial multicellularity include morphological differentiation, programmed cell death and a well-defined and reproducible multicellular shape (known as patterning).The benefits of bacterial multicellularity include predation- and stress-resistance and improved resource acquisition and dispersal.Bacterial multicellular structures that arise via aggregation — for example, in Myxobacteria spp. — are susceptible to the emergence of cheater cells that exploit other cooperative cells.Experimental evolution offers exciting possibilities for understanding the mechanisms and dynamics of the de novo evolution of bacterial multicellularity under defined laboratory conditions.