Author(s)

Jun Zhu^1,2*, Zizhong Zhu^1*, Baoli Zhang¹, Xu Liu¹, Yiping Liu¹, Aiping Zheng^1,2, Shiquan Wang¹, Shuangcheng Li¹, Qiming Deng¹, Huainian Liu¹, Yueyang Liang¹, Ting Zou¹, Aijun Wang¹, Lingxia Wang¹, Ping Li^1,2#

¹Rice Research Institute of Sichuan Agricultural University, Chengdu, China.
²State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Chengdu, China.

Bacillus thuringiensis (Bt) produces two families of insecticidal crystal proteins, i.e., crystalline (Cry) and cytolytic (Cyt) toxins. Cyt3Aa1, the newest Cyt family member, is produced by Bt TD516. Bioassay results have shown that Cyt3Aa1 has weak hemolytic activity against human red blood cells and is not toxic to A. aegypti larvae, but causing a teratogenic effect. The three-dimensional structure of Cyt3Aa1 has a typical cytolysin fold containing a β-sheet held by two surrounding α-helical layers, resembling the previously reported Cyt1Aa and Cyt2Aa structures, which indicated that Cyt3Aa1 might be a membrane-perforation toxin and could induce synergism with Cry protein. This study provides a new source of insecticidal crystal proteins, and presents a foundation for understanding the biological characterization of it, which will aid in the development of strategies to cope with the potential problem of insect resistance.

TD516, Cyt3Aa1, Activity Assays, Three-Dimensional Structure

Zhu, J. , Zhu, Z. , Zhang, B. , Liu, X. , Liu, Y. , Zheng, A. , Wang, S. , Li, S. , Deng, Q. , Liu, H. , Liang, Y. , Zou, T. , Wang, A. , Wang, L. and Li, P. (2020) Characterization of the Novel Insecticidal Crystal Protein Cyt3Aa1 from Bacillus thuringiensis TD516. Advances in Microbiology, 10, 349-358. doi: 10.4236/aim.2020.107025.