Molecular Screening of Behaviorally Active Compounds with CmedOBP14 from the Rice Leaf Folder Cnaphalocrocis medinalis
Odorant binding proteins (OBPs) play a key role in chemoreception in insects. In an earlier study, we identified CmedOBP14 from the rice leaf folder, Cnaphalocrocis medinalis, with potential physiological functions in olfaction. Here, we performed a competitive binding assay under different pH conditions as well as knockdown via RNA interference to determine the specific role of CmedOBP14 in C. medinalis. CmedOBP14 displayed broad binding affinities to many host-related compounds, with higher affinities at pH 7.4 compared with pH 5.0. After treatment with CmedOBP14-dsRNA, the transcript level of OBP14 was significantly decreased at 72 h compared with controls, and the electroantennogram response evoked by nerolidol, L-limonene and beta-ionone was reduced. Furthermore, behavioral assays revealed consistent patterns among these compounds, especially for nerolidol, with adults could no longer able to differentiate 0.1% nerolidol from controls. RNAi experiments suggest that at least in part, CmedOBP14 mediates the ability to smell nerolidol and beta-ionone.
KeywordsOdorant binding proteins RNA interference EAG response Reverse chemical ecology Plant volatiles Behaviorally active compounds
This study was supported and funded by the National Key Research and Development Program of China (2017YFD0200400) and the Special Technical Innovation of Hubei Province (2017ABA146).
Compliance with Ethical Standards
Conflict of Interest
The authors declare no conflict of interest.
- Chang SS, Li GZ (1980) Studies on the migration of rice leaf roller Cnaphalocrocis medinalis Guenee. Acta Entomol Sin 2:130–140Google Scholar
- Kröber T, Koussis K, Bourquin M, Tsitoura P, Konstantopoulou M, Awolola TS, Dani FR, Qiao H, Pelosi P, Latrou K, Guerin PM (2018) Odorant-binding protein-based identification of natural spatial repellents for the African malaria mosquito Anopheles gambiae. Insect Biochem Mol 96:36–50CrossRefGoogle Scholar
- Livak KJ, Schmittgen TD (2001) Analysis of relative gene expression data using real-time quantitative PCR and the 2(-Delta Delta C (T)) method. Methods 25: 402-408Google Scholar
- Obata T, Kim M, Koh H, Hukami H (1981) Planthopper attractants in the rice plant [Oryza sativa]. Jpn J Appl Entomol Zool 25:47–51Google Scholar
- Qin JD, Wang CZ (2001) The relation of interaction between insects and plants to evolution. Acta Entomol Sin:360–365Google Scholar
- Rodriguez-Saona C, Crafts-Brandner SJ, Williams L, Paré P (2002) Lygus hesperus Feeding and salivary gland extracts induce volatile emissions in plants. J Chem Ecol 28: 1733-1747Google Scholar
- Wang Q (2012) Study on effect of Daoteng on Chilo suppressatis, Cnaphalocrocis medinalis and rice stem borer. Sichuan Agricultural UniversityGoogle Scholar
- Zeng FF, Zhao ZF, Yan MJ, Zhou W, Zhang Z, Zhang A, Lu ZX, Wang MQ (2015) Identification and comparative expression profiles of chemoreception genes revealed from major chemoreception organs of the rice leaf folder, Cnaphalocrocis medinalis (Lepidoptera: Pyralidae), PLOS One: e0144267Google Scholar