The Independent Biological Activity of Bacillus thuringiensis Cry23Aa Protein Against Cylas puncticollis

Patricia Hernández-Martínez; Ayda Khorramnejad; Katterine Prentice; Ascensión Andrés-Garrido; Natalia Mara Vera-Velasco; Guy Smagghe; Baltasar Escriche

doi:10.3389/fmicb.2020.01734

The Independent Biological Activity of Bacillus thuringiensis Cry23Aa Protein Against Cylas puncticollis

Front Microbiol. 2020 Jul 22:11:1734. doi: 10.3389/fmicb.2020.01734. eCollection 2020.

Authors

Patricia Hernández-Martínez¹, Ayda Khorramnejad^{1

2}, Katterine Prentice³, Ascensión Andrés-Garrido¹, Natalia Mara Vera-Velasco⁴, Guy Smagghe³, Baltasar Escriche¹

Affiliations

¹ Laboratory of Biotechnological Control of Pest, ERI de Biotecnología y Biomedicina, Department of Genetics, Universitat de València, Burjassot, Spain.
² Laboratory of Biological Control of Pest, Department of Plant Protection, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran.
³ Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.
⁴ Laboratory Membrane Proteins, ERI de Biotecnología y Biomedicina, Department of Biochemistry and Molecular Biology, Universitat de València, Burjassot, Spain.

Abstract

The Cry23Aa/Cry37Aa proteins from Bacillus thuringiensis (Bt) have been described toxic to Cylas puncticollis larvae. In general, it is believed that Cry23Aa and Cry37Aa act jointly to exert the insecticidal activity, while there is no evidence of their toxicity individually. Therefore, in the present study, the contribution of each protein in the insecticidal activity toward C. puncticollis larvae has been assessed. The results showed that both proteins were toxic for C. puncticollis larvae when tested individually. Contrary to what was claimed previously, our results suggest that the presence of both proteins is not necessary to exert toxicity against C. puncticollis larvae. Also, the binding behavior of Cry23Aa protein to midgut receptors of C. puncticollis larvae has been determined. According to our results, Cry23Aa binds to C. puncticollis brush border membrane vesicles (BBMV) specifically and independently of Cry37Aa. Due to the lack of common binding sites, Cry23Aa can be pyramided with Cry3Aa protein for better management of C. puncticollis.

Keywords: Cry37Aa; binary toxin; binding assay; bioassay; insecticidal proteins; mode of action; sweet potato weevils.