Venomics Reveals Venom Complexity of the Piscivorous Cone Snail, Conus tulipa

The piscivorous cone snail Conus tulipa has evolved a net-hunting strategy, akin to the deadly Conus geographus, and is considered the second most dangerous cone snail to humans. Here, we present the first venomics study of C. tulipa venom using integrated transcriptomic and proteomic approaches. Parallel transcriptomic analysis of two C. tulipa specimens revealed striking differences in conopeptide expression levels (2.5-fold) between individuals, identifying 522 and 328 conotoxin precursors from 18 known gene superfamilies. Despite broad overlap at the superfamily level, only 86 precursors (11%) were common to both specimens. Conantokins (NMDA antagonists) from the superfamily B1 dominated the transcriptome and proteome of C. tulipa venom, along with superfamilies B2, A, O1, O3, con-ikot-ikot and conopressins, plus novel putative conotoxins precursors T1.3, T6.2, T6.3, T6.4 and T8.1. Thus, C. tulipa venom comprised both paralytic (putative ion channel modulating α-, ω-, μ-, δ-) and non-paralytic (conantokins, con-ikot-ikots, conopressins) conotoxins. This venomic study confirms the potential for non-paralytic conotoxins to contribute to the net-hunting strategy of C. tulipa.

The complete mitochondrial genome of Conus tulipa (Neogastropoda: Conidae)

The complete mitogenome sequence of the cone snail Conus tulipa (Linnaeus, 1758) has been sequenced by next-generation sequencing method. The assembled mitogenome is 16,599 bp in length, including 13 protein-coding genes, 22 transfer RNA genes and 2 ribosomal RNA genes. The overall base composition of C. tulipa is 28.7% A, 15.2% C, 18.4% G and 37.7% T. It shows 81.1% identity to the cone snail C. consors, 78.5% to C. borgesi and 77.5% to C. textile. Using the 13 protein-coding genes and 2 ribosomal RNA genes of C. tulipa in this study, together with 18 other closely species, we constructed the species phylogenetic tree to verify the accuracy and utility of new determined mitogenome sequence. The complete mitogenome of the C. tulipa provides an essential and important DNA molecular data for further phylogeography and evolutionary analysis for cone snail phylogeny.