Insecticidal effects of Receptor-i isolated bioactive peptides on field collected fire ant colonies

Authors: CHINTA, SATYA - Foresight Science & Technology; Vander Meer, Robert - Bob; Choi, Man-Yeon; O'Reilly, Erin

Submitted to: International Journal of Molecular Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/8/2023
Publication Date: 9/12/2023
Citation: Chinta, S., Vander Meer, R.K., Choi, M.Y., O'Reilly, E.E. 2023. Insecticidal effects of Receptor-i isolated bioactive peptides on field collected fire ant colonies. International Journal of Molecular Sciences. 24(18). https://doi.org/10.3390/ijms241813978.
DOI: https://doi.org/10.3390/ijms241813978

Interpretive Summary: A patented method (Receptor-i technology) for isolating biologically active small peptides (7 amino acids) that act as antagonists to key insect neurophysiological precesses was applied to the red imported fire ant. Ten bioactive peptides were isolated. Feeding/mortality studies narrowed the candidate peptides to four and then to two. Large field collected fully functional fire ant colonies were set up in the laboratory. Each of the two peptides were then continuously fed to the fire ant colonies for 14 weeks. Both bioactive peptides caused significant worker mortality and 5 of 8 queens died. Those surviving queens were very low weight and likely no longer functional. This is the first report that demonstrates the effectiveness of Receptor-i technology generated small peptides for control of imported fire ants, an annual 8.85 billion dollar problem affecting multiple economic sectors.

Technical Abstract: Receptor-i technology uses an insect cell line that in this case, expresses the Pheromone Biosynthesis Activating Neuropeptide receptor (PBAN-R). All fire ant life stages express the PBAN-R. The receptor cell line is challenged with a phage library of millions of randomly synthesized 7 amino acid peptides and through a series of repetitive procedures strong binding 7 amino acid peptides were isolated. These peptides are expected to interfere with the normal functioning of PBAN-R as antagonists or agonists causing disfunction in immatures, workers and the colony queen. Screening the peptides in fire ant acceptance and mortality bioassays identified four promising peptides that were fed to fire ant workers. Two of these, IQQGSHF and MARYMSA gave significantly better worker control. Large fully functional fire ant field colonies (queen, brood, up to 8,000 workers) were set up in the laboratory and were fed 0.1% IQQGSHF or MARYMSA in 10% sucrose solution. Significant worker mortality, queen weight loss and death were observed. These results bring the Receptor-i technology closer to field evaluations and commercial interest.