Diallyl trisulfide causes male infertility with oligoasthenoteratospermia in Sitotroga cerealella through the ubiquitin proteasome pathway

Essential oil extracted from plant sources along with their biologically active components may have negative effects on insect. Diallyl trisulfide (DAT) is an active component of garlic essential oil, and it exhibits multi-targeted activity against many organisms. It has been observed that DAT induces male infertility and leads to dimorphic sperm disruption in Sitotroga cerealella . In this study, we conducted an analysis of testis-specific RNA-Seq data and identified 449 downregulated genes and 60 upregulated genes in the DAT group compared to the control group. The downregulated genes were significantly enriched in the ubiquitin-proteasome pathway. Furthermore, DAT caused a significant reduction in mRNA expression of proteasome regulatory subunit particles required for ATP-dependent degradation of ubiquitinated proteins as well as decreased the expression profile of proteasome core particles, including β1, β2, and β5. Sperm physiological analysis showed that DAT potently inhibited the chymotrypsin-like activity of the 20S proteasome and formed aggresomes in spermatozoa. Computational docking analysis revealed that DAT bound to the active sites of proteasome β1, β2, and β5 subunits, resulting in reversible inhibition. Overall, our findings demonstrate that DAT functions as an inhibitor of the testis-specific proteasome, ultimately causing male infertility characterized by oligoasthenoteratospermia due to disruption in sperm proteasome assembly in S. cerealella.