Small RNAs regulating biofilm formation and outer membrane homeostasis.

Nowadays, the identification of small non-coding RNAs takes a prominent role in deciphering complex bacterial phenotypes. Evidences are given that the post-transcriptional layer of regulation mediated by sRNAs plays an important role in the formation of bacterial biofilms. These sRNAs exert their activity on various targets, be it directly or indirectly linked to biofilm formation. First, and best described, are the sRNAs that act in core regulatory pathways of biofilm formation, such as those regulating motility and matrix production. Second, overlaps between the regulation of biofilm formation and the outer membrane (OM) are becoming obvious. Additionally, different studies indicate that defects in the OM itself affect biofilm formation through this shared cascade, thereby forming a feedback mechanism. Interestingly, it is known that the OM itself is extensively regulated by different sRNAs. Third, biofilms are also linked to global metabolic changes. There is also evidence that metabolic pathways and the process of biofilm formation share sRNAs.