Profiling the venom gland transcriptome of Tetramorium bicarinatum (Hymenoptera: Formicidae): The first transcriptome analysis of an ant species

Animal venoms are complex mixtures containing a range of bioactive elements with potential pharmacological and therapeutic use. Even though ants account among the most diverse zoological group, little information is available regarding their venom composition. To initiate the characterization of the transcriptomic venom gland expression of the ant species Tetramorium bicarinatum, 400 randomly selected clones from cDNA library were sequenced and a total of 364 high quality expressed sequence tags (ESTs) were generated. Based on the results of BLAST searches, these sequences were clustered and assembled into 83 contigs (22 multiple sequences) and 61 singletons. About 74% (267) of the contigs matched BLASTx hits with an interesting diversity together with an unusual abundance of cellular transcripts related to gene expression regulation (29% of the total library) reflecting the specialization of this tissue. About eighteen per cent of the ESTs were categorized as Hymenoptera venom compounds, the major part represented by allergens (62% of the total venom compounds). In addition, a high number of sequences (26%) had no similarity to any known sequences. This study provides a first insight of the gene expression scenario of the venom gland of T. bicarinatum which might contribute to acquiring a more comprehensive view on the origin and functional diversity of venom proteins among ants and more broadly among Hymenopteran insects.