Transcriptome analysis and molecular characterization of soluble chemical communication proteins in the parasitoid wasp (Hymenoptera: Mymaridae).

is an important egg parasitoid wasp of pests such as the rice planthopper. Based on the powerful olfactory system of sensing chemical information in nature, . shows complicated life activities and behaviors, such as feeding, mating, and hosting. We constructed a full-length transcriptome library and used this to identify the characteristics of soluble chemical communication proteins. Through full-length transcriptome sequencing, splicing, assembly, and data correction by Illumina, we obtained 163.59 Mb of transcriptome data and 501,179 items with annotation information. We then performed Gene Ontology (GO) functional classification of the transcriptome's unigenes. We analyzed the sequence characteristics of soluble chemical communication protein genes and identified eight genes: , , , , , , , and . After sequence alignment and conserved domain prediction, the eight proteins encoded by the eight genes above were found to be consistent with the typical characteristics of odorant-binding proteins (OBPs), chemosensory proteins (CSPs), and Niemann-pick type C2 proteins (NPC2s) in other insects. Phylogenetic tree analysis showed that the eight genes share low homology with other species of Hymenoptera. Quantitative real-time polymerase chain reaction (RT-qPCR) was used to analyze the expression responses of the eight genes in different sexes and upon stimulation by volatile organic compounds. The relative expression levels of , , , , and in males were significantly higher than those in females, while the relative expression level of was higher in females. The expression levels of and were significantly altered by the stimulation of β-caryophyllene, suggesting that these two genes may be related to host detection. This study provides the first data for . transcriptome and the molecular characteristics of soluble chemical communication proteins, as well as an opportunity for understanding how . behaviors are mediated via soluble chemical communication proteins.