Fas-associated death domain protein (FADD) functions as an apoptotic adapter in mammals, recruiting caspases for death-inducing signaling complexes, while in lower animals, it interacts with IMD and DREDD to initiate antimicrobial responses. In this study, we examined the T. molitor FADD sequence (TmFADD) using molecular informatics methods to understand its involvement in the host's immune response against microorganisms. Knocking down TmFADD transcripts resulted in increased susceptibility of T. molitor larvae to E. coli, underscoring the significance of FADD in insect defense mechanisms and providing valuable insights into insect immunity.

Pellino, a highly conserved E3 ubiquitin ligase, is known to mediate ubiquitination of phosphorylated Interleukin-1 receptor-related kinase (IRAK) homologs in Toll signaling pathway. To understand the immunological function of TmPellino, we screened the knockdown efficiency of TmPellino by injecting TmPellino-specific dsRNA into T. molitor larvae. Subsequently, we investigated the larval mortality and the tissue-specific expression patterns of antimicrobial peptide (AMP) genes against microbial challenges. Interestingly, the results indicate that the expression of many AMP genes was upregulated in the Malpighian tubules of TmPellino-silenced T. molitor larvae. This study may provide basic information to understand how Tmpellino regulates AMPs production in T. molitor.