title: Bacillus thuringiensis Crystal Protein Cry6Aa Triggers Caenorhabditis elegans Necrosis Pathway Mediated by Aspartic Protease (ASP-1).
abstract: 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.
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.|Haikou Experimental Station, Chinese Academy of Tropical Agricultural Sciences, Haikou, China.
authors.forename: Fengjuan
authors.initials: F
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
authors.forename: Donghai
authors.initials: D
authors.lastname: Peng
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
authors.forename: Chunsheng
authors.initials: C
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
authors.forename: Shouyong
authors.initials: S
authors.lastname: Ju
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
authors.forename: Danfeng
authors.initials: D
authors.lastname: Wan
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
authors.forename: Ziquan
authors.initials: Z
authors.lastname: Yu
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
authors.forename: Jianwei
authors.initials: J
authors.lastname: Shi
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
authors.forename: Yaoyao
authors.initials: Y
authors.lastname: Deng
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
authors.forename: Fenshan
authors.initials: F
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
authors.forename: Xiaobo
authors.initials: X
authors.lastname: Ye
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
authors.forename: Zhenfei
authors.initials: Z
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Lin
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
authors.forename: Lifang
authors.initials: L
authors.lastname: Ruan
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Sun
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D057055:Aspartic Acid Proteases / Q000737:chemistry / Q000378:metabolism*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000378:metabolism*; D017173:Caenorhabditis elegans / Q000201:enzymology*; D002151:Calorimetry; D015180:Electrophoresis, Gel, Two-Dimensional; D004731:Endotoxins / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D006460:Hemolysin Proteins / Q000378:metabolism*; D054884:Host-Pathogen Interactions; D015151:Immunoblotting; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009336:Necrosis; D010572:Pest Control, Biological / Q000379:methods
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D057055:Aspartic Acid Proteases