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

Abstract

Anagrus nilaparvatae 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, A . nilaparvatae 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: AnilOBP2 , AnilOBP9 , AnilOBP23 , AnilOBP56 , AnilOBP83 , AnilCSP5 , AnilCSP6 , and AnilNPC2 . 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 AnilOBP9 , AnilOBP26 , AnilOBP83 , AnilCSP5 , and AnilNPC2 in males were significantly higher than those in females, while the relative expression level of AnilCSP6 was higher in females. The expression levels of AnilOBP9 and AnilCSP6 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 A . nilaparvatae's transcriptome and the molecular characteristics of soluble chemical communication proteins, as well as an opportunity for understanding how A . nilaparvatae behaviors are mediated via soluble chemical communication proteins.

The genome of the rice planthopper egg parasitoid wasps Anagrus nilaparvatae casts light on the chemo- and mechanosensation in parasitism

“…Second, 93.26% of the Illumina clean reads were successfully mapped back to the assembly. Third, 98.83% of the reads of RNA sequencing provided by Ma et al were successfully mapped to the assembly [ 16 ].…”

“…For the ab initio gene prediction, Augustus (V2.5.5) [ 56 ] and GeneMark (V4.32) [ 57 ] were used. For the transcriptome-based prediction, the full-length transcriptomes of A. nilaparvatae [ 16 ] were mapped to the genome assembly using Tophat [ 58 ]. The transcripts were converted to gene models using Cufflinks v2.2.1 [ 59 ].…”

“…In dating the tree, the root age of the prior was set between 203 and 276 Mya [ 5 ]. The divergence between Chalcidoidea and all the other families was constrained at > 130 Mya and the divergence between A. nilaparvatae and other Chalcidoidea species was constrained at 99 ~ 130 Mya [ 5 , 16 ]. We used CAFE v 3.1 to infer the expansion and contraction of gene families along branches of the phylogeny.…”

Functional analysis of odorant-binding proteins for the parasitic host location to implicate convergent evolution between the grain aphid and its parasitoid Aphidius gifuensis

“…Here, EBF induction was performed to identify the OBP proteins that respond with upregulated expression in A. gifuensis. The protocol mainly followed previous studies [38,[55][56][57]. The mummies were separated individually and waited for emergence.…”

Transcriptome Analysis and Identification of Chemosensory Genes in Baryscapus dioryctriae (Hymenoptera: Eulophidae)

“…In Hymenoptera, an enormous number of chemosensory genes from various species have been reported, and most of them have been identified through antennal transcriptomes. According to our statistics from Insectbase 2.0 [18] and the NCBI (National Center for Biotechnology Information (nih.gov)) (accessed on 10 September 2022), chemosensory genes from approximately 4 superfamilies, 18 families and 89 species have been identified, such as Trichogramma pretiosum [19], Anagrus nilaparvatae [20,21], Aenasius bambawalei [22] and Diachasmimorpha longicaudata [23]. In the past five years, an increasing number of studies have investigated the function of chemosensory genes.…”