| Title: | RNAi-based demonstration of direct link between specific odorant receptors and mosquito oviposition behavior |
| Author(s): | Zhu F; Xu P; Barbosa RM; Choo YM; Leal WS; |
| Address: | "Department of Molecular and Cellular Biology, University of California - Davis, Davis, CA 95616, USA" |
| DOI: | 10.1016/j.ibmb.2013.07.008 |
| ISSN/ISBN: | 1879-0240 (Electronic) 0965-1748 (Print) 0965-1748 (Linking) |
| Abstract: | "The Southern house mosquito, Culex quinquefasciatus--a vector of West Nile virus--is equipped with 130 odorant receptors (ORs), which enable young females to locate plants and blood-meal sources and older females to find suitable sites for oviposition. In our attempts to de-orphanize ORs expressed in female antennae, we identified CquiOR37 and CquiOR99, which were narrowly tuned to two phenolic compounds, 4-methylphenol and 4-ethylphenol. When tested in the Xenopus oocyte recording system the observed EC50s for 4-methylphenol and 4-ethylphenol were 6.4 and 18.2 muM for CquiOR37 and 14.4 and 0.74 muM for CquiOR99 (goodness of fit, R(2) = 0.88-0.99), respectively. Indoor behavioral assays demonstrated that gravid female mosquitoes laid significantly more eggs in water trays spiked with these compounds than in control water trays. Field studies with gravid traps corroborated that 4-ethylphenol is active in a wide range of doses from 0.1 to 10 mug/l, as required for practical applications. A dsRNA construct based on the two genes, CquiOR37/99-dsRNA was stable in pupa hemolymph for up to 3 h. Pupae injected with CquiOR37/99-dsRNA, beta-galactosidase-dsRNA or water had more than 40% survival rate at the peak of oviposition (day-9). qPCR analysis showed individual variation, but significant mean reduction in CquiOR37 and CquiOR99 transcript levels in CquiOR37/99-dsRNA-treated mosquitoes. Water-injected females and those treated with the control gene laid significantly more eggs in trays containing 4-ethylphenol than in water trays, whereas CquiOR37/99-dsRNA-treated mosquitoes laid normal number of eggs, but could not discriminate treatment from control. This study linked for the first time specific receptors for 4-ethylphenol with increased oviposition in the important vector Cx. quinquefasciatus" |
| Keywords: | "Animals Behavior, Animal Cloning, Molecular Cresols/*metabolism Culex/*metabolism Female Insect Vectors/metabolism Mosquito Control *Oviposition Phenols/*metabolism Pheromones/metabolism RNA Interference Receptors, Odorant/*metabolism 4-Ethylphenol 4-Meth;" |
| Notes: | "MedlineZhu, Fen Xu, Pingxi Barbosa, Rosangela M R Choo, Young-Moo Leal, Walter S eng R01 AI095514/AI/NIAID NIH HHS/ R01AI095514/AI/NIAID NIH HHS/ Research Support, N.I.H., Extramural Research Support, Non-U.S. Gov't England 2013/08/06 Insect Biochem Mol Biol. 2013 Oct; 43(10):916-23. doi: 10.1016/j.ibmb.2013.07.008. Epub 2013 Aug 2" |
