Abstract：
The abuse of chemical insecticides has led to strong resistance in cockroaches, and biopesticides with active ingredients based on insect pathogens have good development prospects; however, their slow effect has limited their practical application, and improving their effectiveness has become an urgent problem. In this study, the interaction between Serratia marcescens and Metarhizium anisopliae enhanced their virulence against Blattella germanica and exhibited a synergistic effect. The combination of S. marcescens and M. anisopliae caused more severe tissue damage and accelerated the proliferation of the insect pathogen. The results of high-throughput sequencing demonstrated that the gut microbiota was dysbiotic, the abundance of the opportunistic pathogen Weissella cibaria increased, and entry into the hemocoel accelerated the death of the German cockroaches. In addition, the combination of these two agents strongly downregulated the expression of Imd and Akirin in the IMD pathway and ultimately inhibited the expression of antimicrobial peptides (AMPs). S. marcescens released prodigiosin to disrupted the gut homeostasis and structure, M. anisopliae released destruxin to damaged crucial organs, opportunistic pathogen Weissella cibaria overproliferated, broke the gut epithelium and entered the hemocoel, leading to the death of pests. These findings will allow us to optimize the use of insect pathogens for the management of pests and produce more effective biopesticides.
摘要：
滥用化学杀虫剂导致蟑螂产生强烈的抗药性,和以昆虫病原体为活性成分的生物农药具有良好的发展前景；然而，它们的缓慢效果限制了它们的实际应用，提高其有效性已成为一个紧迫的问题。在这项研究中,粘质沙雷氏菌和绿僵菌之间的相互作用增强了它们对德国小球菌的毒力，并表现出协同作用。粘质沙菌和金丝虫的组合引起更严重的组织损伤并加速昆虫病原体的增殖。高通量测序结果表明，肠道微生物群是生态失调的，机会性病原体Weissellacibaria的丰度增加，进入血液中加速了德国蟑螂的死亡。此外,这两种药物的组合强烈下调IMD途径中Imd和Akirin的表达,并最终抑制抗微生物肽(AMPs)的表达。S.marcescens释放prodigiosin破坏肠道稳态和结构，马尾松菌向受损的关键器官释放destruxin，机会性病原体CibbariaWeissella过度增殖，破坏了肠道上皮并进入血液中，导致害虫死亡。这些发现将使我们能够优化使用昆虫病原体来管理害虫，并生产更有效的生物农药。
