# Identification of Candidate Olfactory Genes in the Antennal Transcriptome of Loxostege sticticalis Trapped by Three Different Sex Pheromone Blends

## TL;DR

Researchers identified candidate olfactory genes in the antennae of a destructive agricultural pest, Loxostege sticticalis, using transcriptome analysis of males trapped by different sex pheromone blends.

## Contribution

The study identifies 46 candidate olfactory genes in Loxostege sticticalis, providing a molecular foundation for understanding its chemical signal perception.

## Key findings

- 10,320 differentially expressed genes were identified in the antennal transcriptome of male L. sticticalis.
- Five key gene families related to olfaction were identified, including odorant receptors and chemosensory proteins.
- 46 candidate olfactory genes were selected for further analysis, offering insights into the pest's chemical signal perception.

## Abstract

Loxostege sticticalis is a highly destructive and migratory agriculture pest that feeds on key crops, such as soybeans, corn, and potatoes during its larval stage, causing significant damage to crops. Insects rely on antennal expression receptors to detect olfactory signals and perform essential tasks like finding hosts, attracting mates, and selecting oviposition sites. However, there are few reports on olfactory-related genes in L. sticticalis. The olfactory system plays a central role in the perception of the external environment and the detection of chemical signals released by females. This process involves the synergy of multiple proteins. In this study, the antennal transcriptomes of male L. sticticalis trapped by three different sex pheromone blends were sequenced and characterized. In total, 10,320 differentially expressed genes (DEGs) were identified through transcriptome sequencing and bioinformatics analysis. Furthermore, five gene families that are crucial to insect olfaction were identified among the DEGs, including odorant receptors (ORs), ionotropic receptors (IRs), gustatory receptors (GRs), odorant-binding proteins (OBPs), and chemosensory proteins (CSPs). These results provide a molecular foundation for the further study of the chemical acceptance mechanisms involved in host recognition, localization, and oviposition preference.

Insects sense intraspecific or interspecific information about the chemical substances in the habitat through the sensitive olfactory system to carry out foraging, mating, oviposition, and other activities. The antennae serve as the primary olfactory organs in insects. The olfactory process involves the participation of many proteins, such as odorant-binding proteins (OBPs) and odorant receptors (ORs), but ORs play a central role in olfactory specificity and sensitivity. The beet webworm, Loxostege sticticalis, is an omnivorous agricultural pest that endangers crops and poses a significant risk to the agricultural and animal husbandry production in northern China. In this study, Illumina sequencing was conducted on the antennal transcriptome of male L. sticticalis trapped by three different sex pheromone blends. A total of 10,320 DEGs were identified, from which 46 candidate olfactory genes were selected for further analysis. These candidate olfactory genes comprise 13 odorant receptors, 6 ionotropic receptors (IRs), 3 gustatory receptors (GRs), 12 odorant-binding proteins, and 13 chemosensory proteins (CSPs). In summary, we analyzed the antennal transcriptome of male L. sticticalis trapped by three different sex pheromone blends and identified several candidate olfactory genes. This discovery offers a foundation for further molecular-level investigations into the olfactory system of L. sticticalis.