UV328 Promotes Plastisphere Formation on Microplastics through Quorum-Sensing-Associated Signaling Interference

Abstract Microplastics have created an expanding anthropogenic microbial niche known as the plastisphere, yet the mechanisms by which plastic additives influence these microbial assemblies remain poorly understood. Here, we show that UV328, a ubiquitous benzotriazole stabilizer recently listed in the Stockholm Convention, may be associated with quorum sensing signaling that accelerates plastisphere formation, biomass accumulation, and extracellular polymeric substance production on microplastics. In UV328-exposed polystyrene and polylactic acid plastisphere, the total expression levels of biofilm formation genes are upregulated by 1.38- to 2.94-fold compared to the control and quorum quenching manipulations. Molecular dynamics simulations predict that UV328 structurally mimics N-acyl-homoserine lactone (AHL) and may plausibly occupy ligand-binding domains of the quorum sensing receptor SdiA and CciR with favorable energetics. UV328 exposure was further associated with the upregulation of genes involved in bacterial chemotaxis, flagellar assembly, and central carbon metabolism. This physiological reprogramming alters community assembly trajectories and leads to a protein-rich plastisphere phenotype that was reversible by enzymatic quorum quenching, potentially supporting the involvement of AHL-sensitive processes. Our findings suggest that UV328 can alter plastisphere development through signaling-associated ecological processes, raising the possibility that microplastics may function as chemically active interfaces and highlighting microbial signaling interference as an overlooked dimension of the ecological risks associated with plastic additives in aquatic ecosystems.