Switching on cyclic di-GMP heterogeneity in Pseudomonas aeruginosa biofilms

Abstract

Pseudomonas aeruginosa drives heterogeneity of cyclic di-GMP signalling in biofilms as a division-of-labour strategy to maximize colonization and dispersal using the protein HecE.

Fig. 1 |. The HecRE molecular switch regulates P. aeruginosa biofilm development and heterogeneity through c-di-GMP.

On surface encounter, P. aeruginosa attaches and undergoes asymmetric cell division. A motile, spreader cell with low c-di-GMP that colonizes new environments is generated, as well as a second, attached, striker cell with increased intracellular c-di-GMP, which initiates biofilm formation. As the biofilm develops, environmental signals and autoregulation upregulate HecR, which induces high HecE expression in a subpopulation of cells. HecE activates the c-di-GMP synthase, WspR, and inhibits the phosphodiesterase, BifA, increasing intracellular c-di-GMP and biofilm development. Some biofilm bacteria do not induce HecE and are low in c-di-GMP. As the biofilm matures, this bacterial subpopulation disperses to colonize new areas.