Microbial Chemical Sensing of Microplastic-Derived Compounds in Insect Gut Ecosystems

Microplastic (MP) pollution threatens terrestrial and aquatic ecosystems worldwide. Insects, essential for pollination, decomposition, and nutrient cycling, ingest MPs through feeding and contact. Despite growing evidence of MP-caused gut microbe imbalance, how insect gut microbiomes detect and react to MP leachates, mainly organic additives like phthalates and bisphenol A, is still unclear, limiting our understanding of adaptive resilience against toxicity. This perspective reviews microbial sensing pathways, including two-component systems, ligand-responsive transcriptional regulators, and quorum sensing, which differentiate responses to soluble leachates from inert polymers and orchestrate either enzymatic biodegradation in plastivorous species like Tenebrio molitor or detrimental shifts toward oxidative stress, immune activation via Toll and Imd pathways, and epithelial disruption. These host-microbiota feedbacks influence metabolic homeostasis, vector competence, and ecological processes including trophic transfer and biodiversity. By linking these molecular interactions to ecological processes, we propose the utilization of insect-associated symbionts in bioremediation, guided by omics-based approaches, to develop targeted interventions that mitigate plastic pollution while maintaining ecosystem functionality.