柑橘黄龙病是柑橘生产上的毁灭性病害，近几年黄龙病毁园的果园高达数百万亩，柑橘木虱是传播柑橘黄龙病最重要的虫媒，防治柑橘木虱是防控柑橘黄龙病最经济有效的措施。前期研究中，申请人从罹病的柑橘木虱中分离获得粘质沙雷氏菌，该菌及其代谢产物灵菌红素均对柑橘木虱具有显著的杀虫活性。通过高通量测序和转录组学等前期研究结果表明，粘质沙雷氏菌和灵菌红素的杀虫活性是通过降低体内共生菌和抑制体内抗氧化系统所致。鉴于此，本项目拟研究H2O2、Vc处理柑橘木虱后体内共生菌和ROS的变化，采用qPCR检测和RNAi沉默抗氧化酶基因相互验证的方法，确定粘质沙雷氏菌、ROS和共生菌三者之间的相互关系，阐明粘质沙雷氏菌通过诱导ROS的积累调控共生菌的分子机制。结合荧光工程菌在肠道和血淋巴的定位及肠道上皮细胞的凋亡，进一步解析粘质沙雷氏菌的侵袭模型。通过本研究为柑橘木虱的绿色防控提供新的理论依据和防治策略。

Huanglongbing (HLB) is a devastating disease, which affects citrus production worldwide. In recent years, millions of acres of orange trees have been removed due to HLB. The Asian citrus psyllid, Diaphorina citri Kuwayama, is the major vector of HLB, therefore, the effective method of managing the spread of this pathogen is to suppress the vector populations. In our previous study, we have isolated a strain named as Serratia marcescens KH-001 from D. citri nymphs suffering from disease in citrus orchard, and the strain and its metabolite prodigiosin showed excellent toxic to D. citri; the results of high-throughput sequencing and transcriptomics indicated that the killing effects may be caused by reducing the number of symbiotic bacteria in D. citri and inhibiting antioxidants. Based on the results, the project intends to detect changes of symbiotic bacteria and ROS in citrus psylla treated with H2O2 and Vc, and evaluate relationships among S. marcescens, ROS and symbiotic bacteria with qPCR and RNAi for antioxidant enzyme genes, finally the molecular mechanism that S. marcescens regulates the symbiotic bacteria by inducing the accumulation of ROS will be elucidated. The localization of fluorescence engineering strain in intestine and hemolymph and intestinal epithelial apoptosis will further analyze the invasion model of S. marcescens. This study will provide a new theoretical basis and control strategy for the green control of citrus psyllid.