Identification of Putative Carboxylesterase and GlutathioneS-transferase Genes from the Antennae of theChilo suppressalis(Lepidoptera: Pyralidae)

Abstract

In insects, rapid degradation of odorants in antennae is extremely important for the sensitivity of olfactory receptor neurons. Odorant degradation in insect antennae is mediated by multiple enzymes, especially the carboxylesterases (CXEs) and glutathione S-transferases (GSTs). The Asiatic rice borer, Chilo suppressalis, is an economically important lepidopteran pest which causes great economic damage to cultivated rice crops in many Asian countries. In this study, we identified 19 putative CXE and 16 GST genes by analyzing previously constructed antennal transcriptomes of C. suppressalis. BLASTX best hit results showed that these genes are most homologous to their respective orthologs in other lepidopteran species. Phylogenetic analyses revealed that these CXE and GST genes were clustered into various clades. Reverse-transcription quantitative polymerase chain reaction assays showed that three CXE genes (CsupCXE8, CsupCXE13, and CsupCXE18) are antennae-enriched. These genes are candidates for involvement in odorant degradation. Unexpectedly, none of the GST genes were found to be antennae-specific. Our results pave the way for future researches of the odorant degradation mechanism of C. suppressalis at the molecular level.

Glutathione-S-Transferases in the Olfactory Organ of the Noctuid Moth Spodoptera littoralis, Diversity and Conservation of Chemosensory Clades

“…To test whether this characteristic was shared with the other members of the subclade, we first searched for SP in the sequence of AtraGST (Leal et al, 2009), MsexGST-msolf (Robertson et al, 1999; Rogers et al, 1999), CsupGSTd1 (Liu et al, 2015a) and CmedGSTd1 (Liu et al, 2015b) and we indeed identified putative SPs for all them. We then completed by bioinformatics the N-terminus sequences for the 5 other genes from this clade ( SfruGSTd2, HarmGSTd02, BmGSTd1, EposGST11 , and PxylGSTd1 ) and we also identified predicted SP for each of them.…”

“…However, the expression of GSTs as well as their activities have been also highlighted in the olfactory organs of several insect species. Antennal expressed GSTs have been indeed identified in various moth species, such as Manduca sexta (Rogers et al, 1999), Helicoverpa armigera (Wang et al, 2004), Amyelois transitella (Leal et al, 2009), Bombyx mori (Tan et al, 2014), Chilo suppressalis (Liu et al, 2015a), Epiphyas postvittana (Corcoran et al, 2015), Cnaphalocris medinalis (Liu et al, 2015b), and Cydia pomonella (Huang et al, 2017), but also in the fruit fly Drosophila melanogaster (Younus et al, 2014) or in the beetles Agrilus planipennis (Mamidala et al, 2013), Dendroctonus valens (Gu et al, 2015), and Phyllotreta striolata (Wu et al, 2016). This particular localization led to the hypothesis of a possible dual function of GSTs in antennae where, besides their original implication in xenobiotic metabolism, they could play a role in the signal termination and in odorant clearance, as Odorant-Degrading Enzymes (ODEs, Vogt and Riddiford, 1981; Chertemps, 2017).…”

Degradation of sex pheromone and plant volatile components by an antennal glutathione S‐transferase in the oriental fruit moth,Grapholita molesta Busck (Lepidoptera: Tortricidae)

“…So far, a variety of antennal‐specific and abundant ODE genes of insects have been identified via transcriptome and sequencing. The ODE family genes usually consist of esterase (He et al, ; Vogt & Riddiford, ), aldehyde oxidase (Merlin et al, ; Pelletier et al, ; Y. X. Zhang, Wang, Li, Li, & Liu, ), alcohol dehydrogenase (ADHs; Huang, Liu, Su, & Feng, ), glutathione S ‐transferase (GST; S. Liu, Gong, Rao, Li, & Li, ; X. Tan et al, ), cytochrome P450 oxidoreductase (Hovemann, Sehlmeyer, & Malz, ), and carboxylesterase (CXEs; Chertemps et al, ). GST belong to a kind of important ODEs and play a vital role in phase II enzymic detoxification.…”

Molecular characterization of a typical 2‐Cys thioredoxin peroxidase from the Asiatic rice borer Chilo suppressalis and its role in oxidative stress

“…Chilo suppressalis individuals used in this study originated from a field population collected at an experimental farmland at Anhui Agricultural University, Hefei, Anhui, China (Liu, Gong, Rao, Li, & Li, ). Larvae were reared in our laboratory with rice seedlings, and adult moths were fed on a 10% (v/v) honey solution.…”