Enhancing the oral and topical insecticidal efficacy of a commercialized spider venom peptide biopesticide via fusion to the carrier snowdrop lectin (Galanthus nivalis agglutinin)

Abstract

BACKGROUND: Spear®-T sold as a contact foliar spray for the control of glasshouse pests such as aphids, thrips, spider mites and whiteflies, contains the recombinant spider venom peptide GS-ω/κ-HxTx-Hv1h (named as GS-ω/κ-HxTx-Hv1a by Vestaron) as the active ingredient. Here we investigate whether fusion of the peptide to snowdrop lectin, (Galanthus nivalis agglutinin; GNA) enhances the efficacy of this venom peptide towards aphid pests.Results: Recombinant GS-ω/κ-HxTx-Hv1h (HxTx-Hv1h) and an HxTx-Hv1h/GNA fusion protein were produced using the yeast Pichia pastoris. Purified proteins showed comparable toxicity when injected into lepidopteran (Mamestra brassicae) larvae, but significant differences in oral and contact activity towards aphids. HxTx-Hv1h had comparable acute oral toxicity to pea (Acyrthosiphon pisum) and peach potato (Myzus persicae) aphids with respective Day (2) median lethal concentration (LC 50 ) values of 111 and 108 ∼M derived from diet assays. The fusion protein also showed comparable oral toxicity to both species but D2 LC 50 values were >3-fold lower (35 and 33 ∼M for pea and peach potato aphids, respectively) as compared to HxTx-Hv1h. Topically applied toxin and fusion protein, but not GNA, caused significant reductions in pea aphid survival. Contact effects on mortality were significantly greater for aphids exposed to fusion protein as compared to toxin alone. Whole aphid fluorescence microscopy and immunoblotting suggest that improved efficacy is due to enhanced persistence of HxTx-Hv1h when fused to GNA following internalisation of ingested or topically applied proteins.Conclusions: This is the first study to report on the insecticidal activity of HxTx-Hv1h towards aphids and results suggest that a fusion protein-based approach offers opportunities to significantly enhance oral and contact efficacy of naturally derived toxins, such as HxTx-Hv1h, towards crop pests.

Slowly Making Sense: A Review of the Two-Step Venom System within Slow (Nycticebus spp.) and Pygmy Lorises (Xanthonycticebus spp.)

“…Treatments to mitigate snakebite have dominated venom research: between 81,000 and 138,000 people die each year due to snakebite envenomation, resulting in the World Health Organization listing snakebite as a high-priority neglected tropical disease in June 2017 [ 12 ]. Toxins isolated from venom have been used to develop numerous novel products such as pharmaceuticals (i.e., Captopril, developed from jaraca snake venom ( Bothrops jaracaca ) [ 13 ]), pesticides (i.e., Spear-T by Vestaron, developed from Blue Mountains funnel web spider ( Hadronyche versuta ) [ 14 ]) and even cosmetics (i.e., SensAmone P5 by Mibelle Biochemistry developed from sebae anaemone ( Heteractis crispa ) [ 15 ]).…”

Drosophila X virus‐like particles as delivery carriers for improved oral insecticidal efficacy of scorpion Androctonus australis peptide against the invasive fruit fly, Drosophila suzukii

“…However, because they enter naturally into the blood/hemolymph of other species via a bite or sting (Warrell, 2019), most neurotoxins have not evolved the ability to transverse the gut barriers into the hemolymph, thereby resulting in lower oral insecticidal efficacy (Bonning & Chougule, 2014). In addition, oral ingestion is considered an efficient way for insects to take up neurotoxins from the environment, despite the possibility that a few neurotoxic peptides may be toxic when applied topically (Sukiran et al, 2023). Therefore, developing an efficient delivery system that permits access of neurotoxic peptides to the nervous system is crucial to improve their oral insecticidal efficacy.…”

“…In addition, oral ingestion is considered an efficient way for insects to take up neurotoxins from the environment, despite the possibility that a few neurotoxic peptides may be toxic when applied topically (Sukiran et al. , 2023). Therefore, developing an efficient delivery system that permits access of neurotoxic peptides to the nervous system is crucial to improve their oral insecticidal efficacy.…”