ABSTRACT 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.

中文翻译：

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鳞翅目和鞘翅目物种的钙粘蛋白片段不会增强 Cry1Ca 和 Vip3Aa 蛋白对甜菜夜蛾（Hübner）（鳞翅目：夜蛾科）的毒性

摘要 苏云金芽孢杆菌 Berliner 1915 (Bt) 是一种昆虫病原菌，用于防治世界范围内的害虫。Bt在其生命周期中产生不同的杀虫蛋白，其中植物杀虫蛋白（Vip）和水晶蛋白（Cry）是商业应用最多的。虽然已经报道了大量的 Bt 毒素，但只有少数（如 Cry1Ca 和 Vip3Aa）对世界性害虫甜菜夜蛾（Hübner）（鳞翅目：夜蛾科）表现出毒性。已经开发了多种策略来增强 Bt 毒素的毒性并延迟耐药性的出现，包括添加增效剂。几种协同化合物基于 Cry 受体。尤其是钙粘蛋白受体是跨分类群研究和表征最广泛的受体之一。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 毒素之间的相互作用知之甚少。这项工作的目的是研究两种不同钙粘蛋白片段（来自黄粉虫（Linnaeus）（鞘翅目：黄粉虫科）和甜菜蛾）与两种 Bt 毒素（Cry1Ca 和 Vip3Aa）对鳞翅目害虫 S. exigua 和Grapholitamoleta（Busck）（鳞翅目：Tortricidae）。在我们的方法中，进行了不同 Bt 蛋白：钙粘蛋白片段比例的单剂量反应测定。根据潜在的协同结果，通过剂量反应生物测定准确分析所选混合物，以验证毒性增强。然而，