苏云金芽胞杆菌(简称Bt)是世界上应用最成功、最安全的活菌类杀虫剂。其主要杀虫成分是杀虫晶体蛋白Cry和营养期杀虫蛋白Vip等。目前Cry蛋白的表达调控机制已清楚，但Vip类杀虫蛋白表达调控机制还未知，导致其在Bt制剂中的作用无法发挥。申请人在Bt中发现了一类新型全局性调控因子InpR，并证明InpR是Vip3A杀虫蛋白的主效调控因子，且显著影响Bt的杀虫活性，但其功能和调控机制还未报道。因此本项目拟以高毒力野生型Bt菌株为模型，揭示InpR调控Bt杀虫活性的机制，包括：明确InpR作为新型全局性转录调控因子的特性和功能；鉴定InpR调控Bt杀虫相关的关键靶标和调控网络；最后重点解析InpR调控Vip3A的遗传和生化机制。InpR的功能和机制的揭示可为细菌全局性调控因子研究增加新的成员，并可为通过表达调控提高Vip3A表达量提供理论依据，将为更高效Bt制剂开发提供新的思路。

Bacillus thuringiensis (Bt) is the most successful and safest live microbial insecticide in the world. Its main insecticidal factors are insecticidal crystal protein (Cry) and vegetative insecticidal protein (Vip). By far, the expression regulation mechanism of Cry protein is clear. However, the expression regulation mechanism of Vip-like insecticidal protein is unknown, which resulted in the role of Vip proteins cannot be exerted in existing Bt preparation. Recently, we found a new class of global regulatory factor named as InpR in Bt. We proved that the InpR is the major regulator of Vip3A, and plays important role in the insecticidal activity of Bt. However, the function and regulation mechanism of InpR have not been reported. Therefore, this project intends to reveal the mechanism of how InpR regulating Bt insecticidal activity, including: clarifying the characteristics and functions of InpR as a novel global transcriptional regulator; identifying the key targets for InpR regulation the insecticidal activity of Bt; and explaining the genetic and biochemical mechanisms by which InpR regulates Vip3A insecticidal proteins. The function and mechanism research of InpR will add new models to the study of bacterial global regulatory factors. It will also provide new ideas for the development of more efficient Bt preparations by improving the expression of Vip3A in Bt.