Transcriptomic Screening and Functional Characterization of Immune-Related Genes in Tetranychus urticae Responding to Isaria cateniannulata Infection

Abstract

Simple Summary Tetranychus urticae is a destructive agricultural pest, and Isaria cateniannulata is an important entomopathogenic fungus used for its biological control. To better understand the immune response of Tetranychus urticae to fungal infection, we identified immune-related genes using transcriptome sequencing and investigated the functions of key genes through qRT-PCR, bioinformatics analysis, and RNA interference (RNAi). A total of 342 differentially expressed genes were identified after fungal infection, with many involved in immune-related pathways. Silencing TuAPOD and TuPLA2 significantly increased mite mortality and reduced oviposition when combined with Isaria cateniannulata treatment. These results improve our understanding of the antifungal immune response in Tetranychus urticae and provide a theoretical basis for developing more effective and environmentally friendly biological control strategies.