摘  要  【目的】 作为20E诱导产生的一个关键转录因子，E74在昆虫变态发育过程中起重要调控作用，但该转录因子在螨类中的研究较少。本文旨在探究转录因子E74在柑桔全爪螨Panonychus citri 后若螨到成螨阶段的功能，为害螨提供潜在的防控靶点。【方法】 利用RT-qPCR，明确了E74（PcE74）在柑桔全爪螨后若螨到成螨阶段的表达模式。进一步利用RNA干扰（RNA interference，RNAi）技术，通过人工装置饲喂法，以3种不同的处理（dsRNA，siRNA和dsRNA+siRNA）沉默PcE74，分析沉默效率以确定最佳处理方式，并探究了PcE74在柑桔全爪螨后若螨发育为成螨过程中的作用。【结果】 PcE74在柑桔全爪螨后若螨到成螨各阶段均有表达，后若螨2 h至后若螨16 h表达量上升，后若螨16 h至发育为3日龄成螨表达量递减，成螨阶段表达量相对较低。RNAi表明，与单独饲喂dsPcE74（14%）或siPcE74（24%）相比，饲喂dsPcE74+siPcE74干扰效率显著提高（54%）（P < 0.05），且成螨羽化率显著下降（P < 0.05），异常表型表现为静伏期的后若螨不能产生旧表皮而死亡。dsRNA+siRNA的RNAi效率优于单独使用dsRNA或siRNA。【结论】 PcE74参与调控柑桔全爪螨后若螨到成螨的发育过程，与E74互作的基因调控机制有待进一步研究。

Abstract  [Aim]  E74 is a key transcription factor induced by 20E in insects that plays an important regulatory role in insect metamorphosis and development. However, few studies have been conducted on the role of E74 in mites. This study aims to investigate the function of the transcription factor E74 from Panonychus citri deutonymph to adult and provide potential targets for mite control. [Methods]  RT-qPCR was used to analyze the expression characteristics of E74 during the different developmental stages of P. citri from deutonymph to adult. Three different treatments (dsRNA, siRNA, dsRNA+siRNA) were used to interfere with PcE74 through the leaf-mimicking method using RNAi technology. The silencing efficiency was analyzed to determine the optimal interference mode, and the role of PcE74 was explored during the deutonymph-adult transition. [Results]  PcE74 was expressed during all developmental stages from deutonymph to adult. The expression of PcE74 increased between the 2-hour deutonymph stage to the 16-hour deutonymph stage, before declining during the third instar adult stage where the expression level remained low. The RNAi experiment showed that the interference efficiency of dsPcE74+siPcE74 (54%) was significantly higher than dsPcE74 (14%) and siPcE74 (24%), and the molting percentage was significantly lower than the control (P < 0.05). An abnormal phenotype identified was characterized by the inability of the stationary phase of the deutonymph to produce old epidermis, which resulted in death. siRNA can enhance RNAi efficiency at the phenotypic level, and the RNAi efficiency of dsRNA+siRNA is superior to dsRNA or siRNA. [Conclusion]  PcE74 is involved in the regulation of the developmental process from deutonymph to adult in P. citri. Further investigation is needed on genes that interact with E74 in the molecular regulatory pathway.