The cyanobacterium Synechococcus elongatus is a model organism for the study of
circadian rhythms. It is naturally competent for transformation—that is, it takes up DNA from
the environment, but the underlying mechanisms are unclear. Here, we use a genome-wide
screen to identify genes required for natural transformation in S. elongatus, including genes
encoding a conserved Type IV pilus, genes known to be associated with competence in
other bacteria, and others. Pilus biogenesis occurs daily in the morning, while natural …