Research advances in the herbivore induced plant volatiles through feeding and oviposition

Herbivore-induced plant volatiles (HIPVs), elicited by insect feeding and oviposition, represent evolutionary adaptations in plants that mediate ecological defenses against insects. Here, we systematically review the components, production, induction mechanism, and application prospects of HIPVs. HIPVs comprise a wide variety of compounds, including terpenoids, green leaf volatiles, and aromatic compounds, which are synthesized via unique biosynthetic pathways. The mechanisms by which insects trigger plants to release HIPVs are varied, such as elicitors or microbes in feeding and oviposition secretions, as well as the related leaf damage and egg deposition. Plants recognize invasions through cell membrane receptors, activate early defense signals and phytohormone transmission, upregulate defense-related genes, and ultimately synthesize HIPVs. These volatiles act as toxins against pests in direct defense, while recruit natural enemies and prime defense responses in neighboring plants in indirect defense. Collectively, while significant progress has been made in basic research related to induced defense mechanisms of plant volatiles, future studies should take advantage of biotechnologies like gene-editing technologies to promote insect-resistant plant breeding, and integrate other green control measures for field applications.