Bacillus thuringiensis Crystal Protein Cry6Aa Triggers Caenorhabditis elegans Necrosis Pathway Mediated by Aspartic Protease (ASP-1)

PLoS Pathogens

Donghai Peng¹  Yaoyao Deng²  Fengjuan Zhang²  Jianwei Shi²  Fenshan Wang²  Ziquan Yu²  Chunsheng Cheng²  Zhenfei Hu²  Lifang Ruan²  Shouyong Ju²  Wei Zhou²  Jian Lin²  Danfeng Wan²  Ming Sun²  Xiaobo Ye² 

[1] Haikou Experimental Station, Chinese Academy of Tropical Agricultural Sciences, Haikou, China;State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China

关键词: Necrosis;    Caenorhabditis elegans;    Crystals;    Lysosomes;    Necrotic cell death;    Gastrointestinal tract;    Toxins;    Fluorescence microscopy;   

DOI  :  10.1371/journal.ppat.1005389

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Cell death plays an important role in host-pathogen interactions. Crystal proteins (toxins) are essential components of Bacillus thuringiensis (Bt) biological pesticides because of their specific toxicity against insects and nematodes. However, the mode of action by which crystal toxins to induce cell death is not completely understood. Here we show that crystal toxin triggers cell death by necrosis signaling pathway using crystal toxin Cry6Aa-Caenorhabditis elegans toxin-host interaction system, which involves an increase in concentrations of cytoplasmic calcium, lysosomal lyses, uptake of propidium iodide, and burst of death fluorescence. We find that a deficiency in the necrosis pathway confers tolerance to Cry6Aa toxin. Intriguingly, the necrosis pathway is specifically triggered by Cry6Aa, not by Cry5Ba, whose amino acid sequence is different from that of Cry6Aa. Furthermore, Cry6Aa-induced necrosis pathway requires aspartic protease (ASP-1). In addition, ASP-1 protects Cry6Aa from over-degradation in C. elegans. This is the first demonstration that deficiency in necrosis pathway confers tolerance to Bt crystal protein, and that Cry6A triggers necrosis represents a newly added necrosis paradigm in the C. elegans. Understanding this model could lead to new strategies for nematode control.

【 授权许可】

CC BY