Venom-gland transcriptomics and venom proteomics of the Hentz striped scorpion (Centruroides hentzi; Buthidae) reveal high toxin diversity in a harmless member of a lethal family.

Of the 14 extant scorpion families, Buthidae has the most thoroughly characterized venoms. Most of this characterization, however, has been limited to species with medically significant stings, including members of the Centruroides genus, which have caused human deaths (e.g., Centruroides sculpturatus). To understand the origin and evolution of highly toxic venoms, we should also characterize the more harmless venoms of close relatives. We used Illumina sequencing to separately characterize the venom-gland transcriptomes of a male and female Hentz striped scorpion (Centruroides hentzi) and performed independent quantitative mass-spectrometry analysis of the venom from each individual, providing the first full venom characterization of a Centruroides species that poses no serious threat to humans. We identified 59 venom proteins that were proteomically confirmed, 63 additional transcripts that were identified on the basis of homology to known toxins, and 355 nontoxins expressed in the venom-glands. The most abundant toxins belonged to the Na+ and K+-channel toxin classes. Antimicrobial peptides and peptidases were also identified, along with a large group of venom proteins that could not be classified based on homology, suggesting C. hentzi is a source of previously untapped toxin diversity.