Functional characterization of a pheromone binding protein from rice leaf-folder cnaphalocrocis medinalis in detecting pheromones and host plant volatiles

Authors: SUN, XIAO - Hubei Academy Of Agricultural Sciences; ZHAO, ZHEN-FEI - Hubei Academy Of Agricultural Sciences; ZENG, FANG-FANG - Hubei Academy Of Agricultural Sciences; Zhang, Aijun; LV, ZHONG-XIAN - Hubei Academy Of Agricultural Sciences; WANG, MAN-QUN - Hubei Academy Of Agricultural Sciences

Submitted to: Bulletin of Entomological Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/11/2016
Publication Date: 7/7/2016
Citation: Sun, X., Zhao, Z., Zeng, F., Zhang, A., Lv, Z., Wang, M. 2016. Functional characterization of a pheromone binding protein from rice leaf-folder cnaphalocrocis medinalis in detecting pheromones and host plant volatiles. Bulletin of Entomological Research. 106(6):781-189.

Interpretive Summary: The rice leaf-folder (RLF) is a major leaf-feeding insect pest affecting rice. It is distributed throughout humid regions in tropical to temperate zones and, recently, has become widespread throughout the major rice growing regions in Asia. Feeding activity of RLF larvae on leaves causes significant yield loss in rice by reducing photosynthetic activity. Infestation detection tools for this pest are urgently needed for timely pest management interventions. In previous research, we identified a number of olfactory genes from RLF antennae that were involved in detection of sex attractant and host volatile signals. The current study was focused on a specific olfactory gene highly expressed in male antennae. Our results demonstrated that one type of sensilla on male RLF antennae is responsible for detection of both sex attractants and host plant odorants. Functional characterization of specific olfactory gene and sensilla for RLF sex attractant and host odorant reception could provide further evidence of chemical communication in RLF and help scientists and growers to develop new, environmentally-friendly, semiochemical based alternative pest control strategies for effectively managing RLF populations and reducing the usage of conventional insecticides in rice fields.

Technical Abstract: Pheromone-binding proteins (PBPs) are believed to be involved in the recognition of semiochemicals. In the present study, western blot analysis, fluorescence binding characteristics, and immunolocalization of the CmedPBP4 from rice leaf-folder, Cnaphalocrocis medinalis, were investigated. The western blot analysis revealed that CmedPBP4 showed obvious antenna-specific expression patterns in female and male antennae, with clearly different sex-biased expression. Immunocytochemical labeling revealed that CmedPBP4 exhibited the speci'c expression in the trichoid sensilla. The competitive fluorescence binding assays indicated that CmedPBP4 could selectively recognize three sex pheromone components (Z13-18:Ac, Z11-16:Al and Z13-18:OH) and eleven rice plant volatiles, including cyclohexanol, nerolidol, cedrol, dodecanal, ionone, (-)-a-cedrene, (Z)-farnesene, ß-myrcene, R-(+)-limonene, (-)-limonene, and (+)-3-carene. Meanwhile, the CmedPBP4 detections of sex pheromones and host odorants were pH-dependent. Our results, for the first time, provided further evidence that the trichoid sensilla played an important role in detecting both sex pheromones and host plant volatiles in the C. medinalis moth. Our systematic studies provided further detailed evidence regarding the function of trichoid sensilla in insect semiochemical perception.