Bacillus thuringiensis (Bt), a naturally occurring entomopathogenic soil bacterium, has been the active ingredient of sprayable Bt biopesticides for over a century. Insecticidal Bt Cry proteins are particularly well suited for use as plant-incorporated protectants in transgenic crops (Bt crops) due to their specificity against insect pests and safety for non-target organisms. The sustainability of these Bt products, however, has been challenged by the development of resistance in the field. RNA interference (RNAi), a species-specific control alternative that has been deregulated and commercialized in the USA and Canada, provides a new mode of action to complement the existing Bt products. Based on our preliminary research, we hypothesized that pyramiding/integrating Bt with RNAi can address/manage resistance issues related to Bt traits. To examine this overarching hypothesis, we (1) cloned and characterized a serine/threonine kinase gene (fused) of the Hedgehog (Hh) signaling pathway in the diamondback moth, Plutella xylostella (L.), a global superpest; (2) profiled Pxfused expression in Bt-resistant P. xylostella strains; and (3) investigated the involvement of Pxfused in Bt Cry1Ac resistance in P. xylostella. Pxfused expression was elevated ubiquitously in all Bt-resistant strains, and silencing of Pxfused led to larval and pupal mortality in both Cry1Ac-susceptible and -resistant strains, suggesting that Pxfused is a potential target for RNAi-based resistance management. Taken together, our results not only identify a molecular target to control a devastating lepidopteran pest, but also shed light on a novel resistance management strategy through the integration of two biotechnological techniques with distinct modes of action.

苏云金芽孢杆菌（Bt）是一种天然的昆虫病原土壤细菌，在过去的一个多世纪以来一直是可喷Bt生物农药的活性成分。Bt Cry杀虫蛋白因其对害虫的特异性和对非目标生物的安全性，特别适合用作转基因作物（Bt作物）中植物掺入的保护剂。然而，这些Bt产品的可持续性已受到该领域抗药性发展的挑战。RNA干扰（RNAi）是一种特定于物种的控制替代品，已在美国和加拿大放松管制并商业化，它提供了一种新的作用方式来补充现有的Bt产品。根据我们的初步研究，我们假设将Bt与RNAi金字塔化/整合可以解决/管理与Bt性状相关的抗性问题。小菜蛾小菜蛾（Plutella xylostella（L.））中的刺猬（Hh）信号传导途径的融合）; （2）在抗Bt的小菜蛾菌株中分析了Pxfused表达；（3）研究了Pxfused与小菜蛾对Bt Cry1Ac的抗性有关。在所有对Bt耐药的菌株中，Pxfused的表达普遍提高，而对Cry1Ac敏感和耐药的菌株，Pxfused的沉默导致幼虫和p的死亡率，这表明Pxfused是基于RNAi的抗性管理的潜在目标。综上所述，我们的结果不仅确定了控制毁灭性鳞翅目害虫的分子靶标，而且通过将两种具有不同作用方式的生物技术相结合，揭示了一种新颖的抗药性管理策略。