Background: Chemoreception is critical for insect behaviors such as foraging, host searching and oviposition, and finding mating partners. The process of chemoreception is mediated by a series of proteins, including odorant-binding proteins (OBPs), gustatory receptors (GRs), odorant receptors (ORs), ionotropic receptors (IRs), chemosensory proteins (CSPs) and sensory neuron membrane proteins (SNMPs). The tephritid stem gall fly, Procecidochares utilis Stone, is a type of egg parasitic insect, which is an effective biological control reagent for the invasive weed Ageratina adenophora in many countries. However, the study of molecular components related to the olfactory system of P. utilis has not been investigated. Here, we report the developmental transcriptome (egg, first-third instar larvae, pupae, fame and male adult) of P. utilis using next-generation sequencing technology and identified the major chemosensory related genes. Results: In this study, a total of 133 chemosensory genes in P. utilis transcriptomes were identified by bioinformatics analysis, including 40 OBPs, 29 GRs, 24 ORs, 28 IRs, 6 CSPs, and 6 SNMPs in P. utilis. The sequences of these candidate chemosensory genes were confirmed by BLAST, and phylogenetic analysis was performed. The expression profiles of all candidate genes at different developmental stages were analyzed by differentially expressed genes (DEGs) analysis and then the expression profiles of the OBPs in the seven developmental stages were confirmed by real-time quantitative RT-PCR (qPCR). The results showed that the expression of candidate OBP genes across different developmental stages was consistent with the differentially expressed genes (DEGs) analysis using the fragments per kilobase per million fragments (FPKM) value. Conclusions: A large number of chemosensory genes were identified. This study will provide a significant contribution to the molecular mechanism of chemoreception and help advance the use of P. utilis as biological control agents. Introduction: The chemosensory system is essential for the survival and reproduction of insects. Insects rely on the chemosensory system to identify and analyze volatiles, as well as to distinguish unique chemical signals in their living environment, which play vital roles in their ecological adaptations, host plant location, mate selection, reproductive behavior and other important physiological processes [1, 2]. The system is mediated by several important chemosensory proteins, including odorant-binding proteins (OBPs), chemosensory proteins (CSPs), olfactory receptors (ORs), ionotropic receptors (IRs), and sensory neuron membrane proteins (SNMPs) [2]. OBPs are small, globular, and water-soluble proteins that are recognized as playing an important role in the first step of olfactory recognition [3-5]. Insect OBPs bind and transport hydrophobic odorant molecules through the aqueous lymph within its sensilla to the olfactory receptors (ORs) and activate ORs in the dendritic membranes of the olfactory neurons [6, 7]. Generally, insect...

Background: Chemoreception is critical for insect behaviors such as foraging, host searching and oviposition, and finding mating partners. The process of chemoreception is mediated by a series of proteins, including odorant-binding proteins (OBPs), gustatory receptors (GRs), odorant receptors (ORs), ionotropic receptors (IRs), chemosensory proteins (CSPs) and sensory neuron membrane proteins (SNMPs). The tephritid stem gall fly, Procecidochares utilis Stone, is a type of egg parasitic insect, which is an effective biological control reagent for the invasive weed Ageratina adenophora in many countries. However, the study of molecular components related to the olfactory system of P. utilis has not been investigated. Here, we report the developmental transcriptome (egg, first-third instar larvae, pupae, fame and male adult) of P. utilis using next-generation sequencing technology and identified the major chemosensory related genes.Results: In this study, a total of 133 chemosensory genes in P. utilis transcriptomes were identified by bioinformatics analysis, including 40 OBPs, 29 GRs, 24 ORs, 28 IRs, 6 CSPs, and 6 SNMPs in P. utilis. The sequences of these candidate chemosensory genes were confirmed by BLAST, and phylogenetic analysis was performed. The expression profiles of all candidate genes at different developmental stages were analyzed by differentially expressed genes (DEGs) analysis and then the expression profiles of the OBPs in the seven developmental stages were confirmed by real-time quantitative RT-PCR (qPCR). The results showed that the expression of candidate OBP genes across different developmental stages was consistent with the differentially expressed genes (DEGs) analysis using the fragments per kilobase per million fragments (FPKM) value.Conclusions: A large number of chemosensory genes were identified. This study will provide a significant contribution to the molecular mechanism of chemoreception and help advance the use of P. utilis as biological control agents.