The Molecular and Functional Characterization of Sensory Neuron Membrane Protein 1b (SNMP1b) from Cyrtotrachelus buqueti (Coleoptera: Curculionidae)

Simple SummaryThe bamboo weevil beetle,Cyrtotrachelus buqueti(Coleoptera: Curculionidae) is the primary bamboo pest and seriously influences the development of the bamboo industry. Sensory neuron membrane proteins (SNMPs) play important roles in insect pheromone communication. However, SNMPs ofC. buquetiare still uncharacterized. With the aim of developing control techniques to control this pest, one novelSNMPfromC. buqueti,CbuqSNMP1b, was functionally characterized in this study. The results indicated thatCbuqSNMP1bwas predominantly expressed in the antennae of both sexes and showed significantly higher transcription levels in the adult stage, suggesting thatCbuqSNMP1bis involved in the process of olfaction. Fluorescence binding assays revealed that CbuqSNMP1b could bind to three out of fourteen volatile compounds emitted fromC. buquetiand showed the strongest binding affinity to dibutyl phthalate, demonstrating the role of SNMP1 in detecting odorants. Molecular docking was performed to further understand the binding mode between CbuqSNMP1b and these three ligands, and the results showed that hydrophobic interactions were the prevailing forces within the binding cavities of CbuqSNMP1b. The results of this study will be helpful to understand the function of SNMP1 inC. buquetiand lay a foundation for developing new methods to control this pest.AbstractSensory neuron membrane proteins (SNMPs) play important roles in insect chemoreception and SNMP1s have been reported to be essential in detecting sex pheromones inDrosophilaand some lepidopteran species. However, SNMPs forCyrtotrachelus buqueti(Coleoptera: Curculionidae), a major insect pest of bamboo plantations, remain uncharacterized. In this study, a novelSNMPgene,CbuqSNMP1b, fromC. buquetiwas functionally characterized. The expression ofCbuqSNMP1bwas significantly higher in antennae than in other tissues of both sexes and the expression level was significantly male-biased. Additionally,CbuqSNMP1bshowed significantly higher transcription levels in the adult stage and very low transcription levels in other stages, suggesting thatCbuqSNMP1bis involved in the process of olfaction. Fluorescence binding assays indicated that CbuqSNMP1b displayed the strongest binding affinity to dibutyl phthalate (Ki= 9.03 μM) followed by benzothiazole (Ki= 11.59 μM) and phenol (Ki= 20.95 μM) among fourteenC. buquetivolatiles. Furthermore, molecular docking revealed key residues in CbuqSNMP1b that interact with dibutyl phthalate, benzothiazole, and phenol. In conclusion, these findings will lay a foundation to further understand the olfactory mechanisms ofC. buquetiand promote the development of novel methods for controlling this pest.Keywords:Cyrtotrachelus buqueti;sensory neuron membrane protein;expression pattern;binding assay;molecular docking