ABSTRACT
Quorum sensing (QS) is a microbial communication mechanism that regulates diverse cellular processes and functions. With increasing population density, autoinducers accumulate in the extracellular environment, and once their concentration reaches a threshold, many genes are expressed or repressed. QS systems allow microorganisms to communicate with members of their species. A diversity of QS signaling molecules and specific detection machinery have been described. QS is involved in the regulation of not only virulence but also beneficial traits. However, the need to find novel ways to combat pathogens has prompted the research of the quorum quenching (QQ) phenomenon as an alternative to antibiotics. Beyond the diverse biotechnological applications of the interruption of QS signaling, the QQ phenomenon has ecological implications due to the modulations of microbial interactions in virtually any niche. Multiple studies exemplified AHL degradation activities demonstrating that QQ enzymes are widespread in the natural environment. However, there are few reports on the “natural” relevance of the QQ phenomenon. In this chapter, the ecological relevance of QQ is analyzed from four main points of view: as an alternative for obtaining nutrients in which the AHL degradation products can serve as a source of nutrients and as an energy reserve, as a strategy for the colonization of niches, as protection from toxic compounds, and a regulatory mechanism.
