Exploring quorum sensing in extremophiles: biological roles and phytochemical-based inhibition

Abstract

Quorum sensing (QS) is a cell-density-dependent communication system exhibited by microorganisms that coordinates the expression of genes and collective behavior within a colony through the production and detection of autoinducer molecules. While QS is well researched in mesophiles, its mechanisms and regulation in extremophiles, organisms thriving in conditions like extreme temperature, salinity, and acidity, remain comparatively underexplored, and the strategies in place to inhibit QS in these organisms are narrow, isolate-specific, and often cytotoxic. This review examines QS mechanisms and current inhibition strategies across four extremophilic groups - thermophiles, psychrophiles, halophiles, and acidophiles- and critically evaluates the limitations of existing approaches. Given that phytochemicals, including cinnamaldehyde, curcumin, berberine, resveratrol, etc., have demonstrated significant multitarget QS inhibition efficacy against LuxI/LuxR-type systems in mesophiles, and these pathways are homologously conserved across extremophilic lineages as well. This review proposes phytochemical-based inhibition as a scientifically supported yet largely unexplored avenue to address QS inhibition in extremophilic microorganisms.