Molecular characterization of MyD88 as a potential biomarker for pesticide-induced stress in Bombyx mori

The widespread use of pesticides hampers the immune system of non-target organisms, however, there is a lack of common biomarkers to detect such effects. Myeloid differentiation primary response factor 88 (MyD88) is a crucial junction protein in the Toll-like receptor signaling pathway , which plays an important role in the inflammatory response. In this study, we investigated MyD88 as a potential biomarker for pesticide-induced stress. Phylogenetic analysis revealed that MyD88 was a conserved protein in the evolution of vertebrates and invertebrates. MyD88s usually have death domain (DD) and Toll/interleukin-1 receptor (TIR) domain. Bombyx mori ( B. mori ) is an important economic insect that is sensitive to toxic substances. We found microbial pesticides enhanced the expression level of MyD88 in B. mori . Transcriptome analysis demonstrated that MyD88 expression level was increased in the fatbody after dinotefuran exposure, a third-generation neonicotinoid pesticide. Moreover, the expression of MyD88 was upregulated in fatbody and midgut by imidacloprid , a first-generation neonicotinoid pesticide. Additionally, insect growth regulator (IGR) pesticides, such as methoprene and fenoxycarb , could induce MyD88 expression in the fatbody of B. mori . These results indicated that MyD88 is a potential biomarker for pesticide-induced stress in B. mori . This study provides novel insights into screening common biomarkers for multiple pesticide stresses and important implications for the development of more sustainable pest management strategies.