A novel cry2Ab gene from the indigenous isolate Bacillus thuringiensis subsp. kurstaki

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• Bacillus thuringiensis (Bt) is a soil bacterium producing insecticidal crystal proteins.
• Bt toxins are widely used as biopesticides in agriculture.
• Novel Bt genes are continuously sought for enhanced insecticidal properties.

Purpose of the Study:

• To clone, sequence, and characterize a novel cry2Ab gene from an indigenous Bt isolate.
• To express the cry2Ab25 gene in Escherichia coli and assess the protein's properties.
• To evaluate the insecticidal activity of the expressed Cry2Ab25 toxin against specific insect pests.

Main Methods:

• Gene cloning and sequencing of the cry2Ab25 gene.
• Bioinformatic analysis of the deduced amino acid sequence and phylogenetic comparison.
• Heterologous expression of the cry2Ab25 gene in E. coli BL21(DE3).
• Protein characterization using SDS-PAGE.
• Bioassays to determine insecticidal toxicity against Malacosoma neustria and Rhagoletis cerasi.

Main Results:

• A novel cry2Ab gene, designated cry2Ab25, was successfully cloned and sequenced.
• The cry2Ab25 gene encodes a 633 amino acid protein (70 kDa, pI 8.98) with 99% homology to known Cry2Ab toxins.
• Expressed Cry2Ab25 protein showed significant toxicity against Malacosoma neustria (73% mortality) and Rhagoletis cerasi (75% mortality) within 5 days.

Conclusions:

• The novel cry2Ab25 gene from Bacillus thuringiensis subsp. kurstaki represents a promising candidate for biopesticide development.
• The expressed Cry2Ab25 toxin exhibits potent insecticidal activity against key agricultural pests.
• Further research into the Cry2Ab25 toxin's mechanism and field efficacy is warranted.