Liu Jisheng, Chen Weijian, Situ Jinrong, Li Jiaxuan, Chen Jiahua, Lai Minchun, Huang Fengyi, Li Baoqi
School of Life Sciences, Guangzhou University, Guangzhou 510006, China.
Insects. 2024 Aug 27;15(9):643. doi: 10.3390/insects15090643.
Toll receptors are involved in the development and innate immunity of insects. BmToll9-1 is an important immune receptor in the Toll pathway. Previous studies have focused on its role as a receptor in immune response. In this study, we aimed to investigate the role of BmToll9-1 as a regulator in the immune response. The expression profiles demonstrated that was predominantly expressed in the midgut. RNA interference (RNAi) of was found to be effective in the midgut via the injection of dsRNA, which resulted in smaller and lighter larvae and cocoons. Most signaling genes in the Toll pathway and downstream effector genes were downregulated after the RNAi of . The hemolymph from -silenced larvae showed decreased antibacterial activity against , either in growth curve or inhibition zone experiments. The above results indicate that BmToll9-1 might be positively involved in the immune pathway of silkworm. As a positive regulator, BmToll9-1 might function mainly in the gut to maintain microbial homeostasis to regulate the growth of silkworms. Silencing of downregulates the signaling genes in the Toll pathway and antimicrobial peptide (AMP) production, resulting in decreased antibacterial activity in the hemolymph.
Toll受体参与昆虫的发育和先天免疫。BmToll9-1是Toll通路中的一种重要免疫受体。以往的研究主要集中在其作为免疫反应受体的作用。在本研究中，我们旨在探究BmToll9-1作为免疫反应调节因子的作用。表达谱显示其主要在中肠表达。通过注射dsRNA发现，对其进行RNA干扰在中肠有效，这导致幼虫和茧更小、更轻。在对其进行RNA干扰后，Toll通路中的大多数信号基因和下游效应基因表达下调。在生长曲线或抑菌圈实验中，来自BmToll9-1沉默幼虫的血淋巴对（此处原文缺失相关细菌名称）的抗菌活性降低。上述结果表明，BmToll9-1可能正向参与家蚕的免疫途径。作为一种正向调节因子，BmToll9-1可能主要在肠道发挥作用，以维持微生物稳态来调节家蚕的生长。BmToll9-1的沉默会下调Toll通路中的信号基因和抗菌肽（AMP）的产生，导致血淋巴中的抗菌活性降低。
