title: Exploring complex pheromone biosynthetic processes in the bumblebee male labial gland by RNA sequencing.
abstract: Male marking pheromones (MPs) are used by the majority of bumblebee species (Hymenoptera: Apidae), including a commercially important greenhouse pollinator, the buff-tailed bumblebee (Bombus terrestris), to attract conspecific females. MP biosynthetic processes in the cephalic part of the bumblebee male labial gland (LG) are of extraordinary complexity, involving enzymes of fatty acid and isoprenoid biosynthesis, which jointly produce more than 50 compounds. We employed a differential transcriptomic approach to identify candidate genes involved in MP biosynthesis by sequencing Bombus terrestris LG and fat body (FB) transcriptomes. We identified 12 454 abundantly expressed gene products (reads per kilobase of exon model per million mapped reads value > 1) that had significant hits in the GenBank nonredundant database. Of these, 876 were upregulated in the LG (> 4-fold difference). We identified more than 140 candidate genes potentially involved in MP biosynthesis, including esterases, fatty acid reductases, lipases, enzymes involved in limited fatty acid chain shortening, neuropeptide receptors and enzymes involved in biosynthesis of triacylglycerols, isoprenoids and fatty acids. For selected candidates, we confirmed their abundant expression in LG using quantitative real-time reverse transcription-PCR (qRT-PCR). Our study shows that the Bombus terrestris LG transcriptome reflects both fatty acid and isoprenoid MP biosynthetic processes and identifies rational gene targets for future studies to disentangle the molecular basis of MP biosynthesis. Additionally, LG and FB transcriptomes enrich the available transcriptomic resources for Bombus terrestris.
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: A
authors.initials: A
authors.lastname: Buček
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: J
authors.initials: J
authors.lastname: Brabcová
authors.affiliation: Max Planck Institute for Chemical Ecology, Jena, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Vogel
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: D
authors.initials: D
authors.lastname: Prchalová
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: J
authors.initials: J
authors.lastname: Kindl
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: I
authors.initials: I
authors.lastname: Valterová
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: I
authors.initials: I
authors.lastname: Pichová
mesh_terms: D000445:Aldehyde Oxidoreductases / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D001516:Bees / Q000378:metabolism*; D005216:Fat Body / Q000378:metabolism; D044943:Fatty Acid Desaturases / Q000378:metabolism; D005227:Fatty Acids / Q000096:biosynthesis; D006868:Hydrolysis; D050356:Lipid Metabolism; D008297:Male; D008969:Molecular Sequence Data; D010675:Pheromones / Q000096:biosynthesis*; D016133:Polymerase Chain Reaction; D017423:Sequence Analysis, RNA; D013729:Terpenes / Q000378:metabolism; D059467:Transcriptome
chemical_list: D005227:Fatty Acids; D010675:Pheromones; D013729:Terpenes; D044943:Fatty Acid Desaturases; D000445:Aldehyde Oxidoreductases; C027902:fatty acid reductase
keywords: Bombus terrestris; RNA-seq; apoptosis; labial gland; marking pheromone biosynthesis; transcriptome