The role of specialized metabolites in plant‒insect interactions: A review.

Plants have evolved sophisticated defense mechanisms against phytophagous insects through long-term coevolution, while insects have developed diverse adaptive strategies to overcome plant defenses. Plant specialized metabolites (SMs), also known as secondary metabolites, comprise a diverse group of chemical compounds, many of which function as chemical defenses against insect herbivores. A better understanding of the roles of plant SMs in plant-insect interactions should facilitate development of novel biopesticides, the exploitation of pest-resistance traits for crops, and the development of sustainable strategies of insecticide resistance managements. In this review, we summarize the regulation mechanisms underlying the biosynthesis and accumulation of plant SMs in response to insect herbivory, discuss the multiple effects of plant SMs on insect behavior, physiology, and development, and describe the adaptive mechanisms that enable insects to cope with plant chemical defenses. Finally, we highlight future research directions and discuss the potential applications of plant SMs in sustainable pest management. This review provides a comprehensive overview of plant‒insect interactions mediated by plant SMs and offers perspectives for developing environmentally friendly pest management strategies.