# Transcriptome Analysis and Identification of Chemosensory Genes in Leguminivora glycinivorella

## TL;DR

Researchers identified genes in the soybean pod borer that help it detect chemical signals, which could lead to better pest control methods.

## Contribution

The study provides a comprehensive identification and expression analysis of chemosensory genes in Leguminivora glycinivorella.

## Key findings

- 183 candidate chemosensory genes were identified, including odorant, gustatory, and ionotropic receptors.
- Sex-specific gene expression patterns suggest roles in pheromone detection and host plant interaction.
- Absence of certain sensory gene groups may reflect adaptation to soybean feeding.

## Abstract

The soybean pod borer is a serious soybean pest because its larvae feed inside pods and damage developing seeds, making conventional insecticide control difficult. To support the development of safer and more effective management strategies, we investigated the genes that may help this insect detect chemical cues from host plants, mates, and its surroundings. By analyzing transcriptome data from multiple adult tissues, we identified 183 candidate genes related to chemical sensing. Many of these genes showed clear differences in expression among tissues and between females and males. In particular, genes associated with odor detection were mainly enriched in the antennae, the primary sensory organs for smelling. Male antennae showed high expression of several candidate genes that may be involved in pheromone detection, whereas some genes were more highly expressed in females and may contribute to host finding and egg-laying site selection. We also found that some expected sensory gene groups were absent from the dataset, which may be related to the insect’s close adaptation to soybean. These results provide a foundation for future functional studies and may help support environmentally friendly pest control based on chemical communication.

The soybean pod borer, Leguminivora glycinivorella, is a monophagous pest that threatens soybean production. Its larvae feed concealed within pods, which limits the efficacy of conventional insecticides. Elucidating its chemosensory system is therefore essential for developing green, behavior-based management strategies. Reference-based transcriptomics across multiple tissues of L. glycinivorella identified a comprehensive repertoire of chemosensory genes, including 76 odorant receptors (ORs), 15 gustatory receptors (GRs), 18 ionotropic receptors (IRs), 52 odorant-binding proteins (OBPs), 18 chemosensory proteins (CSPs), and 4 sensory neuron membrane proteins (SNMPs). Sequence and phylogenetic analyses characterized these candidates within the context of known insect chemosensory families. Notably, canonical bitter GRs and specific IR lineages (e.g., IR100/IR85a) were not detected in our dataset, potentially reflecting adaptation to the specialized soybean-feeding habit of this pest. Expression profiling further revealed pronounced sexual and tissue dimorphism: male antennae showed significant enrichment of putative pheromone receptors (PRs) and LglySNMP1, whereas several OBPs and ORs exhibited female-biased expression, suggesting roles in host location and oviposition. Additionally, the high expression of GR43a homologs points to fructose sensing, while the lack of detectable CO2 receptor components (except LglyGR2) suggests atypical carbon dioxide perception mechanisms. Collectively, this study provides a valuable expression atlas of chemosensory genes in L. glycinivorella and identifies sex-specific candidate genes for future functional validation and behavior-based pest management.