JVATiTD - Articles

Official publication of CEVAP/UNESP

Identification and recombinant expression of an antimicrobial peptide (cecropin B-like) from soybean pest Anticarsia gemmatalis

Luís Felipe Costa Ramos1, João Henrique de Oliveira Rangel1, Guilherme Caldas Andrade1, Carolina Lixa1, Livia Vieira Araujo de Castilho1,2, Fábio César Sousa Nogueira1, Anderson S. Pinheiro1, Fabio Mendonça Gomes3, Cristiane Dinis AnoBom1, Rodrigo Volcan Almeida1, Danielle Maria Perpétua de Oliveira1 [ + show more ]

J Venom Anim Toxins incl Trop Dis, 2021, 27:e20200127
Received: 24 August 2020 | Accepted: 11 January 2021 | Published online: 12 March 2021
Collection: Arthropods: venoms and biology


Background: Insects can be found in numerous diverse environments, being exposed to pathogenic organisms like fungi and bacteria. Once these pathogens cross insect physical barriers, the innate immune system operates through cellular and humoral responses. Antimicrobial peptides are small molecules produced by immune signaling cascades that develop an important and generalist role in insect defenses against a variety of microorganisms. In the present work, a cecropin B-like peptide (AgCecropB) sequence was identified in the velvetbean caterpillar Anticarsia gemmatalis and cloned in a bacterial plasmid vector for further heterologous expression and antimicrobial tests. Methods: AgCecropB sequence (without the signal peptide) was cloned in the plasmid vector pET-M30-MBP and expressed in the Escherichia coli BL21(DE3) expression host. Expression was induced with IPTG and a recombinant peptide was purified using two affinity chromatography steps with Histrap column. The purified peptide was submitted to high-resolution mass spectrometry (HRMS) and structural analyses. Antimicrobial tests were performed using gram-positive (Bacillus thuringiensis) and gram-negative (Burkholderia kururiensis and E. coli) bacteria. Results: AgCecropB was expressed in E. coli BL21 (DE3) at 28°C with IPTG 0.5 mM. The recombinant peptide was purified and enriched after purification steps. HRMS confirmed AgCrecropB molecular mass (4.6 kDa) and circular dichroism assay showed α-helix structure in the presence of SDS. AgCrecropB inhibited almost 50% of gram-positive B. thuringiensis bacteria growth. Conclusions: The first cecropin B-like peptide was described in A. gemmatalis and a recombinant peptide was expressed using a bacterial platform. Data confirmed tertiary structure as predicted for the cecropin peptide family. AgCecropB was capable to inhibit B. thuringiensis growth in vitro.


Keywords: Antimicrobial peptides; Cecropin B; Heterologous expression; Anticarsia gemmatalis; Agricultural pest.

Full Article PDF