Molecular diversity and evolutionary trends of cysteine-rich peptides from the venom glands of Chinese spider Heteropoda venatoria

Abstract

Background: The huntsman spider ( Heteropoda venatoria Carl Linnaeus, 1767) in family Sparassidae, is highly valued in tropical and subtropical countries because the species capture and feed on cockroaches and other domestic insect pests. Unlike most other species of Araneomorphae, the huntsman spiders do not use webs to capture prey. Their great speed and strong chelicerae (mouthparts) with toxin glands are used to capture the insects.Results: We identified 154 novel putative cysteine-rich peptide toxin precursors by analyzing expressed sequence tags of the spider H. venatoria venom gland. The sequences of cysteine-rich peptide precursor revealed 24 families based on the phylogenetics analyses of signal peptide and cysteine framework in mature region, including 8 families of classic Inhibitory cystine knot toxins, 2 families of novel 6-cys motifs, 13 families of long cysteine-rich peptides with 8, 10 and 12-cys, and one family of 2-cys peptides. Intriguingly, four kinds of motifs are first described in spider venom. Furthermore, combining the diverse cysteine-rich peptide sequences of H. venatoria with the sequences from represent spiders explored previously, the dynamic evolutionary trends of venom cysteine-rich peptides were investigated based on the analysis of the structures of precursors and the patterns of cysteine scaffolds in the phylogenetic framework.Conclusion: H. venatoria is an appropriate intermediate species for the evolutionary analysis of spider peptide toxins from Mygalomorphae to Araneomorphae with a holistic view. This work revealed the dynamic evolutionary trends of venom cysteine-rich peptides of spider: the mature peptides have been developed longer with more cysteines; and the propeptides between the signal and mature peptides have been diminished and even vanished. With respect to potential insecticidal applications, the work provides promising new templates and gene clones for further exploration.