BdorOBP32 Perceiving β-Caryophyllene: A Molecular Target for Female Attractant Development in <i>Bactrocera dorsalis</i>

<i>Bactrocera dorsalis</i> is a destructive agricultural pest that attacks over 600 plant species. β-Caryophyllene is considered a potential compound for developing novel female attractants due to its attraction to <i>B. dorsalis</i> females. However, the unknown perception mechanism of β-caryophyllene has been the bottleneck of this process. Odorant binding proteins (OBPs) function to bind odorants and transport them to olfactory receptors. Here, behavioral assays revealed that β-caryophyllene strongly attracted mated, instead of virgin females. RT-qPCR confirmed <i>BdorOBP32</i> up-regulation out of five <i>OBPs</i> in mated females compared to virgin females. Microscale thermophoresis (MST) results showed BdorOBP32 bind β-caryophyllene with relatively high affinity. Subsequently, CRISPR/Cas9 knockout of <i>BdorOBP32</i> reduced electroantennograms responses and behavioral preferences to β-caryophyllene in mutants. Moreover, molecular docking and behavioral analysis identified a novel female attractant (α-angelica lactone) targeting BdorOBP32. These findings highlight BdorOBP32 plays critical roles in β-caryophyllene perception and offer new insights for developing novel olfactory behavior modulators.