Meeting Abstract
Annelida is a diverse phylum that includes earthworms, leeches, and many marine worms, and currently comprises approximately 20,000 species described with a variety of different lifestyles. Within annelids, some groups are known to produce toxins as a defense mechanism against predators and parasites or for prey capture. Although previous studies have focused only in a few groups because of pharmaceutical or insecticides uses (for example hematophagous leeches, and nereis toxin for insecticides), some recent studies in glycerids, amphinomids, and phyllodocids have shown that our understanding of toxin diversity and evolution in annelids is largely unknown. To study toxin diversity, 296 annelid transcriptomes from 91 families were analyzed (66 were retrieved from SRA) by sequence similarity using BLASTp against the SWISSPROT database. To identify putative toxin genes, BLAST reports were manually searched for hits to sequences previously identified by SWISSPROT as toxins or venoms. Preliminary analyses recovered 363 toxin-like genes for 288 out of the 296 transcriptomes, with most of the transcriptomes without toxin hits belonging to sipunculan species. The resulting hits were grouped into gene classes based on the SWISSPROT annotation of toxin genes with the most common including metalloproteinase M12, kunitz, peptidase S1, phospolypase B (PLB), and fibrinogen C terminal domain-like classes. PLB transcripts have been previously reported in amphinomid and glycerid annelid, but are best known from hymenopterans and snakes. Interestingly, homologs of PLB were present in 80% of the transcriptomes, thus our results suggest that genes associated with PLB are common among annelids. Additionally, homology searches using HMMER and Pfam databases are being conducted for cross validation of current results. Individual toxin families will be selected for phylogenetic analyses.
