N-dodecanoyl-L-homoserine lactone (C12-HSL) drives biofilm formation in Pseudomonas aeruginosa by binding and activating the quorum-sensing regulator RhlR, which then induces transcription of the psl operon—encoding glycosyltransferases (e.g., PslI, PslJ) and other poorly characterized proteins (PslA, PslB, PslD-PslO) that synthesize and export the sticky Psl polysaccharide, a critical biofilm scaffold that binds cells to surfaces and each other. Simultaneously, RhlR-C12-HSL upregulates the rhlAB operon, producing rhamnolipids that structure the biofilm by creating nutrient channels and reducing surface tension for microcolony expansion. This dual regulation—Psl for matrix integrity and rhamnolipids for architectural dynamics—ensures robust biofilm development, with C12-HSL acting as the central signal coordinating these processes through RhlR-mediated gene activation.

Quorum sensing: N-dodecanoyl-L-homoserine lactone (C12-HSL) Biofilm Regulation References