RNA interference of odorant receptor CquiOR114/117 affects blood-feeding behavior in Culex quinquefasciatus

The odorant receptors (ORs) play a critical role for mosquitoes in the identification of blood-feeding hosts and other physiological processes. The OR8 subfamily in mosquitoes has been shown to be strongly involved in the detection the mammalian host associated odor, 1-octen-3-ol. CquiOR114/117 has been shown to be an orthologous OR8 in Culex quinquefasciatus Say. In this study, the expression of CquiOR114/117 in the different developmental stages of Cx. quinquefasciatus was detected by the amplification of CquiOR114/117 with real-time fluorescence quantitative polymerase chain reaction (PCR). RNA interference (RNAi) technology was used to interfere with the expression of CquiOR114/117 in females to observe the blood-feeding behavior change. The results showed that the expression level of CquiOR114/117 in the egg-to-pupa stage was significantly lower than that in the adult stage and that the expression level of the female mosquitoes peaked on the third day after emergence. The expression of CquiOR114/117 was significantly decreased in the 2-6 days after the injection of dsRNA compared with the control groups. The analysis of the blood-feeding behavior showed a significant positive correlation between CquiOR114/117 expression and the engorgement rate of the mosquitoes. CquiOR114/117 is speculated to have an effect on the blood-feeding behavior of Cx. quinquefasciatus.