Bacillus thuringiensis Berliner 1915 (Bt) is an entomopathogenic bacterium used to control insect pest worldwide. During its life cycle, Bt produces different insecticidal proteins, among which Vegetative Insecticidal Proteins (Vip) and Crystal proteins (Cry) are the most commercially used. Although large number of Bt toxins have been reported, only few of them (such as Cry1Ca and Vip3Aa) showed toxicity to the cosmopolitan pest Spodoptera exigua (Hübner) (Lepidoptera:Noctuidae). Diverse strategies have been developed to enhance the toxicity of Bt toxins and to delay the onset of resistance, including the addition of synergistic agents. Several synergistic compounds are based on Cry receptors. Especially cadherin receptor is one of the most widely studied and characterised across-taxa. In this regard, the insect cadherin fragments can enhance the toxicity of Cry insecticidal toxins, although less is known about the interaction between cadherin fragments and Vip toxins. The purpose of this work is to study the synergistic effect on toxicity of two different cadherin fragments (from Tenebrio molitor (Linnaeus) (Coleoptera: Tenebrionidae) and S. exigua) with two Bt toxins (Cry1Ca and Vip3Aa) on the lepidopteran pests S. exigua and Grapholita molesta (Busck) (Lepidoptera:Tortricidae). In our methodology, single dose response assays at different Bt protein:cadherin fragment ratios were performed. Upon potential synergistic results, the selected mixture was accurately analysed by dose–response bioassays to verify toxicity enhancement. However, no robust synergistic effect was observed after testing all the combinations of insect species-toxin-cadherin fragment, confirming that synergistic effects of cadherin fragments may not be generalised for all combinations.

苏云金杆菌（Bacillus thuringiensis Berliner）1915（Bt）是一种致病性细菌，用于控制全世界的害虫。在其生命周期中，Bt产生不同的杀虫蛋白，其中最常用的是植物性杀虫蛋白（Vip）和晶体蛋白（Cry）。尽管已经报道了大量的Bt毒素，但只有少数（如Cry1Ca和Vip3Aa）对大都会害虫斜纹夜蛾有毒性。（Hübner）（鳞翅目：Noctuidae）。已经开发出多种策略来增强Bt毒素的毒性并延迟耐药性的发作，包括添加协同剂。几种协同化合物基于Cry受体。尤其是钙粘蛋白受体是跨类群研究最广泛和特征之一。在这方面，昆虫钙粘蛋白片段可以增强Cry杀虫毒素的毒性，尽管对钙粘蛋白片段和Vip毒素之间相互作用的了解还很少。这项工作的目的是研究两种钙粘蛋白片段（来自黄粉虫（Linnaeus）（鞘翅目：Tenebrionidae）和S. exigua）与两种Bt毒素（Cry1Ca和Vip3Aa）对鳞翅目害虫的协同作用。S. exigua和Grapholita molesta（Busck）（鳞翅目：T科）。在我们的方法中，以不同的Bt蛋白：钙黏着蛋白片段比例进行了单剂量反应测定。根据潜在的协同效果，通过剂量反应生物测定法准确分析所选混合物，以验证毒性增强作用。但是，在测试昆虫物种-毒素-钙黏着蛋白片段的所有组合后，未观察到强大的协同作用，这证实了钙黏着蛋白片段的协同作用可能未针对所有组合均被推广。