A transcriptomic and proteomic atlas of expression in the Nezara viridula (Heteroptera: Pentatomidae) midgut suggests the compartmentalization of xenobiotic metabolism and nutrient digestion

Abstract

Background: Stink bugs are an emerging threat to crop security in many parts of the globe, but there are few genetic resources available to study their physiology at a molecular level. This is especially true for tissues such as the midgut, which forms the barrier between ingested material and the inside of the body. Results: Here, we focus on the midgut of the southern green stink bug Nezara viridula and use both transcriptomic and proteomic approaches to create an atlas of expression along the four compartments of the anterior-posterior axis. Estimates of the transcriptome completeness were high, which led us to compare our predicted gene set to other related stink bugs and Hemiptera, finding a high number of species-specific genes in N. viridula. To understand midgut function, gene ontology and gene family enrichment analyses were performed for the most highly expressed and specific genes in each midgut compartment. These data suggested a role for the anterior midgut (regions M1-M3) in digestion and xenobiotic metabolism, while the most posterior compartment (M4) was enriched in transmembrane proteins. A more detailed characterization of these findings was undertaken by identifying individual members of the cytochrome P450 superfamily and nutrient transporters thought to absorb amino acids or sugars. Conclusions: These findings represent an initial step to understand the compartmentalization and physiology of the N. viridula midgut at a genetic level. Future studies will be able to build on this work and explore the molecular physiology of the stink bug midgut.

A spatiotemporal atlas of the lepidopteran pest Helicoverpa armigera midgut provides insights into nutrient processing and pH regulation

“…GO term overrepresentation analysis (Table S6) showed that genes commonly overexpressed in the midgut of all larval stages are related to digestive functions such as lipid metabolism (GO:0006629) and proteolysis (GO:0006508). This finding was also observed in the stink bug N. viridula, and is commonplace among insects as it has been proven that they play an important role in the breakdown of proteins in the ingested food [17,30,31].…”

“…For L2, L3, and L4 midguts, dissected samples were sent to the Centre for Proteomics (Antwerp, Belgium) for gel-free analysis as was described previously [ 17 ]. For spatial compartment analysis of artificial diet fed L5 samples, a gel-based approach was used at the Proteomics Facility of the Institute of Molecular Biology and Biotechnology (Heraklion, Greece).…”

“…Tissue expression atlases that report gene transcription across tissues or life stages have proven useful for researchers investigating molecular physiology in including model insects such as Drosophila and broader databases like Genevestigator [ 15 , 16 ]. The falling cost of sequencing has also allowed this approach to be deployed in non-model organisms as was recently accomplished for the midgut of Nezara viridula [ 17 ]. The economic impact of Lepidoptera has generated substantial interest in these organisms and particularly the lepidopteran midgut since it is the target tissue of the widely used insecticidal Bt toxins.…”

Comparative and functional genomics of the ABC transporter superfamily across arthropods

“…To study the potential roles of hemipteran specific ABC-H transporters, we used RNAi to individually knock down the expression of several ABC-H genes in the stink bug N. viridula . Using previous transcriptomic information [ 47 ]⁠, it was observed that the ABC-H genes were expressed primarily in the M4 midgut region and non-gut tissue (Table S7 ). We selected 8 out of 14 genes for RNAi knockdown based on high expression levels.…”

Genome-Wide Identification and Characterization of Amino Acid Polyamine Organocation Transporter Family Genes Reveal Their Role in Fecundity Regulation in a Brown Planthopper Species (Nilaparvata lugens)

“…To explore the spatial-temporal expression pattern of each APC transporter in BPHs, the RNA-seq data at 15 developmental stages (egg-24 h, egg-48 h, egg-5 days, 1st-24 h, 1st-48 h, 2nd-24 h, 2nd-48 h, 3rd-24 h, 3rd-48 h, 4th-24 h, 4th-48 h, 5th-24 h, 5th-48 h, female adult-24 h, and female adult-72 h) and five tissues (head, salivary glands, integument, gut, and ovaries) were downloaded from the NCBI database (SRR13958477-SRR13958499) 11 . A pseudoalignment-based software, Kallisto v0.46.1, was used to quantify the transcript abundance in transcripts per million (TPM) counts for each identified gene ( Denecke et al, 2020 ; Sheng et al, 2021 ). After the expression data of all APC transporter genes were obtained, two heatmaps illustrating the expression profiles of each APC member at different developmental stages and different tissues of the BPH were generated using TBtools.…”