非典型Bt伴胞晶体蛋白鉴定及功能研究

苏云金芽孢杆菌（Bt）区别其它芽孢杆菌最重要的特征是芽孢期能够产生杀虫伴胞晶体蛋白(Cry和Cyt毒素)。然而，申请人对从海南岛热带雨林分离的400多株Bt菌株进行了全基因组测序，发现扫描电镜能够明显观察到伴胞晶体存在的Bt菌株，基因组序列并不能鉴定到传统的Cry和Cyt伴胞晶体蛋白基因序列及同源序列。蛋白质质谱分析进一步证明伴胞晶体也非surface layer protein (SLP)组成。其原因可能是Bt“伴胞晶体蛋白”不仅仅限于Cry、Cyt和 SLP蛋白组成。本项目将运用基因异源表达、基因突变和蛋白互作等技术手段探究这种非典型伴胞晶体蛋白的组成结构和生物学功能。

Bacillus thuringiensis(Bt) produces unique proteinaceous parasporal crystalline inclusions (also known as δ-endotoxins: Cry and Cyt) during sporulation, which is the most important character that discriminates among the taxonomically closely related species such as B. cereus, B. anthracis, etc. However, the recent studies based on more than 400 Bt strain genome sequencing data showed that a number of Bt strain with the clear morphology of crystalline inclusion failed to identify the homologues of the known cry, cyt, or slp genes. Mass spectrometry was carried out to further confirmed that the composition of the parasporal protein were also not composed of the surface layer protein (SLP). Therefore, we concluded that these atypical parasporal crystalline inclusions (APCI) were present originally which differ from the traditional insecticidal crystal protein composed of the Cry, Cyt or SLP protein. In this study, the techniques such as heterologous expression, gene mutation and protein interaction(pull down, Co-Immunoprecipitation etc.), would be used to explore the composition and biological functions of atypical parasporal crystalline inclusions