蜡样芽孢杆菌是自然界广泛存在的一类具有多种功能的微生物。在医学领域有些蜡样芽孢杆菌是致病菌，其分泌产生的肠毒素可引起呕吐和腹泻等症状。但是在农业及环境科学领域，有些蜡样芽孢杆菌属于益生菌，可以促进植物生长、提高植物的抗病性，还可以用于治理环境污染等。本课题组从小麦根部分离的内生细菌中得到一株对小麦纹枯病具有良好生防效果的蜡样芽孢杆菌，构建了该菌株的转座子插入突变体库，并从该库中筛选得到一批生物薄膜形成能力显著下降的突变体菌株。经反向PCR及序列比对发现其中一株是蜡样芽孢杆菌磷酸转移酶系统组成成分EI蛋白编码基因被转座子插入突变所导致的，该菌株的定殖能力也有显著下降。基于上述前期研究基础，本项目拟对蜡样芽孢杆菌磷酸转移酶系统的结构、功能、各组分之间的互作等进行深入的研究，同时也将对蜡样芽孢杆菌磷酸转移酶系统与该菌发挥生防作用之间的相关性进行初步的探讨，从一定角度揭示蜡样芽孢杆菌的生防机理。

Bacillus cereus is a multifunctional microbe existed widely in the nature. In the medicine area, some Bacillus cereus strains are pathogenic bacteria that can secrete enterotoxin cause symptoms such as vomiting and diarrhea. While in the agricultural and environmental sciences, some Bacillus cereus strains belong to the probiotics that can promote the plant growth and plant disease resistance and also used for the environmental pollution controlling. Our group obtained an entophytic Bacillus cereus strain from the wheat root with good biocontrol effect on wheat sharp eyespot and constructed a transposon random insertional mutant library. From this mutant library, we screen out 10 mutant strains that have a reduced ability of biofilm formation. By inverse PCR and sequence comparison, we found a mutant strain that its EI coding gene sequence was inserted with a TnYLB-1 transposon and has a significant reduction in the ability of colonization. The phosphoenolpyruvate-dependent phosphotransferase system (PTS) is a highly conserved carbohydrate transport system in bacteria and the EI enzyme is a component of the phosphotransferase system. Based on the basis of the preliminary study, this project intends to study the structure, function and component interaction of the phosphotransferase system. At the same time, the correlation between the phosphotransferase system and biocontrol effect of Bacillus cereus will discussed in order to reveal the biocontrol mechanism of this bacteria.