The Effects of Gene Function of Endophytic Fungus OW 7.8 on Its Swainsonine Biosynthesis.

The gene in the endophytic fungus OW 7.8 isolated from was identified, and the gene knockout mutant Δ was first constructed in this study. Compared with OW 7.8, the Δ mutant exhibited altered colony and mycelia morphology, slower growth rate, and no swainsonine (SW) in mycelia. SW was detected in the gene function complementation strain Δ/, indicating that the function of the gene promoted SW biosynthesis. Six differentially expressed genes (DEGs) closely associated with SW synthesis were identified by transcriptomic analysis of OW 7.8 and Δ, with , , , , and down-regulating, and up-regulating. The expression levels of the six genes were consistent with the transcriptomic analysis results. Five differential metabolites (DEMs) closely associated with SW synthesis were identified by metabolomic analysis, with -glutamate, α-ketoglutaric acid, and -proline up-regulating, and phosphatidic acid (PA) and 2-aminoadipic acid down-regulating. The SW biosynthetic pathways in OW 7.8 were predicted and refined. The results lay the foundation for in-depth elucidation of molecular mechanisms and the SW synthesis pathway in fungi. They are also of importance for the prevention of locoism in livestock, the control and utilization of locoweeds, and the protection and sustainable development of grassland ecosystems.