Knockdown of a Nicotinic Acetylcholine Receptor Subunit Gene Bdorβ1Decreases Susceptibility to Oxa-Bridged trans- instead of cis-Nitromethylene Neonicotinoid Insecticides in Bactrocera dorsalis

Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels that mediate the fast action of acetylcholine in synaptic cholinergic transmissions. Insect nAChRs are the target of several classes of insecticides. Here, the full-length cDNA encoding a nAChR beta1 subunit (Bdorβ1) was identified and characterized from a destructive pest, Bactrocera dorsalis. The amino acid sequence of Bdorβ1 shows high identities to other insect nAChRs β1 subunits. Double injection of dsBdorβ1reduced the expression of Bdorβ1and in turn significantly decreased susceptibility to oxa-bridged trans- instead of cis-nitromethylene neonicotinoids. Our results support the involvement of Bdorβ1in the susceptibility of B. dorsalisto oxa-bridged trans- instead of cis-nitromethylene neonicotinoids and imply that these two classes of neonicotinoids might be acting at different nAChR subtypes.