Immunotranscriptomic Profiling of Spodoptera frugiperda Challenged by Different Pathogenic Microorganisms

<i>Spodoptera frugiperda</i> is a globally significant migratory agricultural pest that requires proactive monitoring. Understanding the molecular mechanisms underlying the interactions between pathogenic microorganisms and <i>S. frugiperda</i> is crucial for enhancing the effectiveness of microbial control agents against this pest. This study used transcriptome sequencing and molecular biology techniques on <i>S. frugiperda</i> larvae infected by bacteria and fungi to investigate the composition and molecular regulatory mechanisms of its immune system. A total of 598 immune-related genes were identified. Upon microbial infection, most immune-related genes showed an upregulated expression trend. Phylogenetic analysis revealed that the immune gene repertoire of <i>S. frugiperda</i> is relatively conserved. The expression of the genes of <i>peptidoglycan recognition proteins</i> in different tissues of <i>S. frugiperda</i> induced by microorganisms at different times was verified using qPCR, and the results confirmed that these genes were significantly upregulated under specific pathogenic infections. This study elucidates the immune transcriptome of <i>S. frugiperda</i> in response to various pathogenic microorganisms, providing valuable insights for improving the effectiveness of existing microbial agents and developing new, highly efficient, and specific biopesticides.