Isolation of an orally active insecticidal toxin from the venom of an Australian tarantula

Hardy, Margaret C., Daly, Norelle L., Mobli, Mehdi, Morales, Rodrigo A. V. and King, Glenn F. (2013) Isolation of an orally active insecticidal toxin from the venom of an Australian tarantula. PLoS ONE, 8 9: e73136.1-e73136.12. doi:10.1371/journal.pone.0073136


 
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Author Hardy, Margaret C.
Daly, Norelle L.
Mobli, Mehdi
Morales, Rodrigo A. V.
King, Glenn F.
Title Isolation of an orally active insecticidal toxin from the venom of an Australian tarantula
Journal name PLoS ONE   Check publisher's open access policy
ISSN 1932-6203
Publication date 2013-09-11
Sub-type Article (original research)
DOI 10.1371/journal.pone.0073136
Open Access Status DOI
Volume 8
Issue 9
Start page e73136.1
End page e73136.12
Total pages 12
Place of publication San Francisco, CA, United States
Publisher Public Library of Science
Collection year 2014
Language eng
Formatted abstract
Many insect pests have developed resistance to existing chemical insecticides and consequently there is much interest in the development of new insecticidal compounds with novel modes of action. Although spiders have deployed insecticidal toxins in their venoms for over 250 million years, there is no evolutionary selection pressure on these toxins to possess oral activity since they are injected into prey and predators via a hypodermic needle-like fang. Thus, it has been assumed that spider-venom peptides are not orally active and are therefore unlikely to be useful insecticides. Contrary to this dogma, we show that it is possible to isolate spider-venom peptides with high levels of oral insecticidal activity by directly screening for per os toxicity. Using this approach, we isolated a 34-residue orally active insecticidal peptide (OAIP-1) from venom of the Australian tarantula Selenotypus plumipes. The oral LD50 for OAIP-1 in the agronomically important cotton bollworm Helicoverpa armigera was 104.2±0.6 pmol/g, which is the highest per os activity reported to date for an insecticidal venom peptide. OAIP-1 is equipotent with synthetic pyrethroids and it acts synergistically with neonicotinoid insecticides. The three-dimensional structure of OAIP-1 determined using NMR spectroscopy revealed that the three disulfide bonds form an inhibitor cystine knot motif; this structural motif provides the peptide with a high level of biological stability that probably contributes to its oral activity. OAIP-1 is likely to be synergized by the gut-lytic activity of the Bacillus thuringiensis Cry toxin (Bt) expressed in insect-resistant transgenic crops, and consequently it might be a good candidate for trait stacking with Bt.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes ARC Discovery Grant DP0774245

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2014 Collection
Institute for Molecular Bioscience - Publications
 
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Created: Tue, 24 Sep 2013, 09:08:54 EST by Maggie Hardy on behalf of Institute for Molecular Bioscience