Bioscience Methods 2024, Vol.15, No.6, 302-314 http://bioscipublisher.com/index.php/bm 306 the RISC that mediates the cleavage of viral RNA. Additionally, other small RNA pathways, such as those involving microRNAs (miRNAs), may also contribute to the antiviral response. Viruses, in turn, have evolved various strategies to evade RNAi, including the production of RNAi suppressors that inhibit the host's RNAi machinery. Understanding the molecular regulation of RNAi in earwigs can provide insights into the coevolutionary arms race between hosts and pathogens and highlight potential targets for enhancing antiviral defenses (Nakad et al., 2016; Berkhout, 2018; Lazzaro, 2018). 5 Response to Fungal, Bacterial, and Viral Infections 5.1 Immune responses to fungal pathogens Earwigs, like other insects, possess a robust innate immune system that provides the first line of defense against fungal pathogens. The immune response to fungal infections involves several key components, including pattern recognition receptors (PRRs) that detect fungal cell wall components such as beta-glucan and chitin. These PRRs trigger signaling pathways that lead to the production of antimicrobial peptides and other immune effectors (Silipo et al., 2010). Additionally, the immune response includes the activation of cellular mechanisms such as phagocytosis by hemocytes, which engulf and destroy fungal cells. Recent studies have highlighted the role of regulated cell death (RCD) in fungal defense. RCD is a genetically controlled process that eliminates infected cells, thereby preventing the spread of the pathogen. This mechanism is similar to the hypersensitive response observed in plants and involves several distinct pathways characterized by different biochemical and morphological features (Gaspar and Pawlowska, 2022). Furthermore, the immune response to fungal pathogens can vary depending on the virulence of the fungal strain, with different genes being expressed in response to high- and low-virulence strains (Wang et al., 2020). 5.2 Defense mechanisms against bacterial infections Earwigs employ multiple strategies to defend against bacterial infections. One of the primary mechanisms involves the recognition of bacterial microbe-associated molecular patterns (MAMPs) such as lipopolysaccharides (LPS) and peptidoglycan (PGN) by PRRs. This recognition triggers a cascade of immune responses, including the production of antimicrobial peptides that target and kill bacteria. The innate immune system also involves the activation of signaling pathways such as the Toll and Imd pathways, which regulate the expression of immune-related genes and coordinate the overall immune response (Yu et al., 2022). In addition to these molecular mechanisms, earwigs utilize physical barriers such as the cuticle to prevent bacterial entry. Hemocytes play a crucial role in the immune response by phagocytosing bacteria and releasing reactive oxygen species (ROS) to kill the pathogens. The interplay between immune cells and non-immune cells, such as epithelial cells, further enhances the defense against bacterial infections (Netea et al., 2015). 5.3 Viral immune suppression and molecular pathways The immune response to viral infections in earwigs involves both RNA silencing and innate immunity. RNA silencing is a sequence-specific mechanism that targets viral RNA for degradation, thereby preventing viral replication. This process is mediated by small RNAs such as microRNAs (miRNAs) and short interfering RNAs (siRNAs), which are produced by Dicer-like proteins. In addition to RNA silencing, earwigs utilize innate immune pathways to combat viral infections. Viruses have evolved various strategies to suppress the host immune response, including the production of viral suppressors that inhibit RNA silencing and other immune pathways. These viral effectors can interfere with the recognition of viral components by PRRs and inhibit the signaling pathways that lead to the production of antiviral molecules (Zvereva and Pooggin, 2012). The interplay between viral suppression mechanisms and the host immune response is a critical area of research, as it provides insights into the molecular pathways involved in viral defense and the evolution of host-pathogen interactions. In summary, earwigs employ a combination of RNA silencing and innate immune responses to defend against viral infections. The ability of viruses to suppress these immune mechanisms highlights the ongoing evolutionary
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