Comparation of pheromone-binding proteins 1 and 2 of Spodoptera frugiperda in perceiving the three sex pheromone components Z9-14:Ac, Z7-12: Ac and Z11-16: Ac

Pheromone-binding proteins (PBPs) are mainly responsible for binding and transporting hydrophobic pheromone molecules across the aqueous sensilla lymph to the receptor proteins. The preference of each PBP is believed to be different for each pheromone component within a single species. Significantly higher expression level of PBP1 and PBP2 in the male antennae of Spodoptera frugiperda suggesting that SfruPBP1 and SfruPBP2 might play important roles in pheromone perception. However, the preference of these two PBP to the three main pheromone components Z9-14: Ac, Z7-12: Ac and Z11-16: Ac have not been determined. In this study, a fluorescence competitive binding assay revealed that the binding intensities of SfruPBP1 and SfruPBP2 to Z9-14: Ac or Z7-12: Ac was comparable. We then used the CRISPR/Cas9 system to individually or simultaneously knock out PBP1 and PBP2 in S.frugiperda. The result of courtship behavior indicated that SfruPBP1 and SfruPBP2 were indispensable and played equal roles in perceiving the pheromones Z9-14: Ac and Z7-12: Ac for orientation, wing vibration, and hair-pencil display. Compared with Z9-14:Ac and Z7-12: Ac, Z11-16: Ac showed higher or medium binding intensities with SfruPBP1 and SfruPBP2 but played a minor role in inducing the wing vibration behavior. The results of this study are valuable for elucidating the mechanisms involved in sex pheromone perception and may facilitate the development of PBP-targeted pest control techniques.