A ShK-like domain from Steinernema carpocapsae with bioinsecticidal potential

• Autor(a) principal: Frias, Jorge
• Data de Publicação: 2022
• Outros Autores: Toubarro, Duarte, Bjerga, Gro Elin Kjæreng, Puntervoll, Pål, Vicente, João B., Reis, R. L., Simões, Nelson
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: https://hdl.handle.net/1822/81210
• topic: Entomopathogenic nematodes; Excretory/secretory products; Disulfide-rich peptide; ShK; Insecticidal toxins; Fruit fly; Toxicity assay; Locomotor activity; excretory; secretory products; Science & Technology

Entomopathogenic nematodes are used as biological control agents against a broad range of insect pests. We ascribed the pathogenicity of these organisms to the excretory/secretory products (ESP) released by the infective nematode. Our group characterized different virulence factors produced by <i>Steinernema carpocapsae</i> that underlie its success as an insect pathogen. A novel ShK-like peptide (ScK1) from this nematode that presents high sequence similarity with the ShK peptide from a sea anemone was successfully produced recombinantly in <i>Escherichia coli</i>. The secondary structure of ScK1 appeared redox-sensitive, exhibiting a far-UV circular dichroism spectrum consistent with an alpha-helical secondary structure. Thermal denaturation of the ScK1 allowed estimating the melting temperature to 59.2 ± 0.1 °C. The results from toxicity assays using <i>Drosophila melanogaster</i> as a model show that injection of this peptide can kill insects in a dose-dependent manner with an LD₅₀ of 16.9 µM per adult within 24 h. Oral administration of the fusion protein significantly reduced the locomotor activity of insects after 48 h (<i>p</i> < 0.05, Tukey’s test). These data show that this nematode expresses insecticidal peptides with potential as next-generation insecticides.