Spider venom neurotoxin based bioinsecticides: A novel bioactive for the control of the Asian citrus psyllid Diaphorina citri (Hemiptera)

Miranda, Marcelo P; Fitches, Elaine C; Sukiran, Nur Afiqah; Eduardo, Wellington I; Garcia, Rafael B; Jaciani, Fabrício J; Readshaw, Jennifer J; Bell, Jack; Peña, Leandro

Abstract

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is a key vector of the phloem-limited bacteria Candidatus Liberibacter asiaticus (CLas) associated with huanglongbing (HLB), the most serious and currently incurable disease of citrus worldwide. Here we report the first investigation into the potential use of a spider venom-derived recombinant neurotoxin, ω/κ-HxTx-Hv1h (hereafter HxTx-Hv1h) when delivered alone or when fused to snowdrop lectin (Galanthus nivalis agglutinin; GNA) to control D. citri. Proteins, including GNA alone, were purified from fermented transformed yeast Pichia pastoris cultures. Recombinant HxTx-Hv1h, HxTx-Hv1h/GNA and GNA were all orally toxic to D. citri, with Day 5 median lethal concentrations (LC50) derived from dose-response artificial diet assays of 27, 20 and 52μM, respectively. Western analysis of whole insect protein extracts confirmed that psyllid mortality was attributable to protein ingestion and that the fusion protein was stable to cleavage by D. citri proteases. When applied topically (either via droplet or spray) HxTx-Hv1h/GNA was the most effective of the proteins causing >70 % mortality 5 days post treatment, some 2 to 3-fold higher levels of mortality as compared to the toxin alone. By contrast, no significant mortality or phenotypic effects were observed for bumble bees (Bombus terrestris L.) fed on the recombinant proteins in acute toxicity assays. This suggests that HxTx-Hv1h/GNA has potential as a novel bioinsecticide for the management of D. citri offering both enhanced target specificity as compared to chemical pesticides and compatibility with integrated pest management (IPM) strategies.

Citation

Miranda, M. P., Fitches, E. C., Sukiran, N. A., Eduardo, W. I., Garcia, R. B., Jaciani, F. J., …Peña, L. (2024). Spider venom neurotoxin based bioinsecticides: A novel bioactive for the control of the Asian citrus psyllid Diaphorina citri (Hemiptera). Toxicon: An Interdisciplinary Journal on the Toxins Derived from Animals, Plants and Microorganisms, 239, Article 107616. https://doi.org/10.1016/j.toxicon.2024.107616

• Journal Article Type: Article
• Acceptance Date: Jan 10, 2024
• Online Publication Date: Jan 12, 2024
• Publication Date: Feb 23, 2024
• Deposit Date: Jan 19, 2024
• Publicly Available Date: Jan 19, 2024
• Journal: Toxicon
• Print ISSN: 0041-0101
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 239
• Article Number: 107616
• DOI: https://doi.org/10.1016/j.toxicon.2024.107616
• Keywords: Toxicology
• Public URL: https://durham-repository.worktribe.com/output/2148772