Niemann–Pick C2 proteins play crucial role in perception of plant volatiles in Tetranychus cinnabarinus

Abstract BACKGROUND Herbivorous mites perceive odorants through olfactory mechanisms, though the molecular basis of olfaction in these species remains poorly understood. Recent studies have identified Niemann–Pick C2 (NPC2) proteins as odorant carriers in the peripheral olfactory systems of insects. Multiple NPC2 genes have been discovered in spider mite genomes, yet their specific roles in olfactory function have not been fully explored. RESULTS Behavioral assays showed that 8 of the 12 tested plant volatiles elicited either repellent or attractive responses in Tetranychus cinnabarinus . Two NPC2 genes were identified as responsive to odorant stimulation. Recombinant NPC2 proteins were produced, and microscale thermophoresis (MST) assays revealed specific binding: TcinNPC2‐2 bound to geranylacetone [dissociation constant (Kd) = 3.32 μ m ], and TcinNPC2‐3 bound to farnesol (Kd = 9.55 μ m ). Knockdown of NPC2 genes via RNA interference abolished mite responses to these odorants in behavioral assays. CONCLUSIONS Mite olfactory responses to a number of odorants were widely documented. NPC2‐2 and NPC2‐3 proteins play critical roles in the olfactory detection of geranylacetone and farnesol, respectively. This study enhances our understanding of the peripheral olfactory processes in herbivorous mites, offering insights for the development of behavior‐targeting agents for mite control. © 2025 Society of Chemical Industry.