Analysis of Chemosensory Genes in Full and Hungry Adults of Arma chinensis (Pentatomidae) Through Antennal Transcriptome

Abstract

The predatory insect Arma chinensis (Hemiptera: Pentatomidae) is widely distributed in China, where it is also used to control many agricultural and forest pests. The chemosensory genes expressed in its antennae play crucial roles in food-seeking and mating behaviors. To better understand the olfaction of A. chinensis antennae, we identified the genes related to food-seeking and mating. Sequencing of the antennal transcriptomes of full and hungry male and female A. chinensis revealed 38 odorantbinding proteins (OBPs), 1 chemosensory protein (CSP), 1 Niemann-Pick C2 protein (NPC2), 3 odorant receptors (ORs), 12 ionotropic receptors (IRs), 2 gustatory receptors (GRs), and 3 sensory neuron membrane proteins (SNMPs). These results were used to construct phylogenetic trees. A quantitative real-time PCR (qRT-PCR) analysis showed that the relative transcript levels of AchiGR1, AchiGR2, and AchiOBP28 were higher in female than in male antennae in both full and hungry insects, but that the expression of AchiOBP13 and AchiOBP16 was higher only in full A. chinensis females. Thus, the latter genes may encode proteins involved in oviposition selection behavior. AchiGRs (1 and 2), AchiIR6, and AchiOBPs (6-8, 12, 20-22, 28, and 34) were highly expressed only in the antennae of full males, indicating the participation of these genes in mate-searching or male pheromone recognition. The expression of AchiOBP31 in the antennae of starved males, AchiOBPs (15, 18, and 29) in the antennae of starved females, and AchiOBPs (3, 4, and 24) in the antennae of starved males and females suggested that these genes encode food-seeking functions. Our identification of chemosensory genes in A. chinensis antennae and their differential expression in full and hungry insects provides the basis for further functional studies on the chemoreception system of A. chinensis and the sex hormones of predatory insects.

Comparative transcriptome analysis of the antenna and proboscis reveals feeding state-dependent chemosensory genes in Eupeodes corollae

“…The expression levels of 10 differentially expressed EcorOBPs were upregulated in the feeding treatment group. Similar observations were made in other studies, such as with a study of the predator Arma chinensis, which showed that two and nine AchiOBPs were upregulated in the female and male antennae, respectively, after feeding [69]. Only EcorCSP7 was downregulated in the feeding treatment group in our study, consistent with findings in Glossina morsitans where the expression levels of GmorCSP2 increased in females after starvation for 48 h [70,71].…”

Antennal Transcriptome Analysis and Identification of Candidate Chemosensory Genes of the Harlequin Ladybird Beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae)

“…However, antennal transcriptomes from other predatory insects exhibited variable numbers of ORs. For instance, only 15 ORs could be identified in the antennal transcriptome of Cyrtorhinus lividipennis Reuter (Hemiptera: Miridae) [ 17 ], 14 ORs in Chrysopa pallens (Rambur) [ 14 ] and 37 ORs in Chrysoperla sinica (Neuroptera: Chrysopidae) [ 15 ], 51 ORs in Episyrphus balteatus DeGeer and 42 ORs in Eupeodes corollae Fabricius (Diptera: Syrphidae) [ 18 ], and 38 ORs in Arma chinensis (Fallou) (Hemiptera: Pentatomidae) [ 92 ]. Hopefully, further identification of OR genes in other predatory insect antennae will permit to increase coverage of probable unknown putative OR genes in these insects.…”

Antennal transcriptome analysis and identification of candidate chemosensory genes of the harlequin ladybird beetle,Harmonia axyridis(Pallas) (Coleoptera: Coccinellidae)

“…However, antennal transcriptomes from other predatory insects exhibited variable numbers of ORs. For instance, only 15 ORs could be identified in the antennal transcriptome of Cyrtorhinus lividipennis Reuter (Hemiptera: Miridae) [17], 14 ORs in Chrysopa pallens (Rambur) [14] and 37 ORs in Chrysoperla sinica (Neuroptera: Chrysopidae) [15], 51 ORs in Episyrphus balteatus DeGeer and 42 ORs in Eupeodes corollae Fabricius (Diptera: Syrphidae) [18], and 38 ORs in Arma chinensis (Fallou) (Hemiptera: Pentatomidae) [92]. Hopefully, further identification of OR genes in other predatory insect antennae will permit to increase coverage of probable unknown putative OR genes in these insects.…”