Exploring complex pheromone biosynthetic processes in the bumblebee male labial gland by RNA sequencing

Area of Science:

• * Insect chemical ecology and molecular biology.
• * Focus on Hymenoptera, specifically Bombus terrestris.

Background:

• * Male marking pheromones (MPs) are crucial for reproduction in most bumblebee species.
• * The biosynthesis of MPs in the male buff-tailed bumblebee (Bombus terrestris) labial gland (LG) is complex, involving numerous enzymes.

Purpose of the Study:

• * To identify candidate genes responsible for MP biosynthesis in Bombus terrestris.
• * To analyze differential gene expression between the LG and fat body (FB) to pinpoint MP-related genes.

Main Methods:

• * Differential transcriptomic sequencing of Bombus terrestris LG and FB.
• * Analysis of gene expression levels (reads per kilobase of exon model per million mapped reads).
• * Validation of candidate gene expression using quantitative real-time reverse transcription-PCR (qRT-PCR).

Main Results:

• * Identified 12,454 abundantly expressed gene products with significant database hits.
• * Discovered 876 genes upregulated in the LG compared to the FB (>4-fold difference).
• * Pinpointed over 140 candidate genes potentially involved in fatty acid and isoprenoid-based MP biosynthesis.

Conclusions:

• * The Bombus terrestris LG transcriptome provides insights into MP biosynthetic pathways.
• * Identified key gene targets for future research into the molecular mechanisms of MP production.
• * Generated valuable transcriptomic data for Bombus terrestris LG and FB.