苏云金芽胞杆菌（Bt）中绝大多数杀虫晶体蛋白（ICPs）的表达依赖于芽胞形成，为了从细胞水平研究晶体与芽胞形成之间的关系，本文选用Bt 4.0718与工程菌Bt ΔleuB为研究对象，利用FM464对不同生长阶段的菌体细胞染色，并用激光共聚焦扫描显微镜进行了对比观察和分析。结果显示,Bt 4.0718芽胞的发育依次经历了不对称隔膜和内吞形态学阶段后，能顺利进入下一个发育阶段，直至完成芽胞发育过程后母细胞凋亡裂解；而Bt ΔleuB细胞进入不对称隔膜期的时间明显延迟，且芽胞发育被阻滞于内吞阶段，伴胞晶体形成最早于不对称隔膜期可见，并且晶体体积继续增大直至细胞死亡。qRTPCR结果显示，σE、
spoIIR和spoIIGA的高水平转录是维持Bt ΔleuB细胞中ICPs正常表达的关键因素。本研究结果对进一步揭示晶体与芽胞形成之间的关系及构建性状优良Bt工程菌具有一定的参考价值。

The expression of most insecticidal crystal proteins (ICPs) in Bacillus thuringiensis (Bt) is dependent on spore formation. In order to study the relationship between ICPs expression and spore formation at the cellular level, a pair of strains Bt 4.0718 and Bt ΔleuB were selected and subjected to FM464 staining at different growth stages for a laser confocal microscope observation. Results showed that the Bt 4.0718 strain underwent the asymmetric septum and forespore engulfment stages successively, and could enter into the next stage and successfully complete the entire process of spore development before the mother cell apoptosis. The asymmetric septum stage of Bt ΔleuB was significantly delayed, and the spore development was arrested in forespore engulfment. The crystals were visible since the asymmetric cell division stage, and the volume continued to increase until the mother cell died. qRTPCR result revealed that the high transcriptional level of σE, spoIIR and spoIIGA is a key factor to maintain the normal expression of ICPs in Bt ΔleuB cells. These results possessed a certain reference value for further revealing the relationship between sporulation and ICPs expression, and construction of engineering strains with better behavior.