The Effects of swnK Gene Function of Endophytic Fungi Alternaria oxytropis OW 7.8 on its Swainsonine Biosynthesis

Genomic sequencing of Alternaria oxytropis OW 7.8 isolated from Oxytropis glabra was performed, the swnK gene was cloned and knocked out firstly. The colony morphology of ΔswnK-ACP differed from that of A. oxytropis OW 7.8, appearing milky white or pale yellow, with irregular shapes and a slower growth rate. SW was not detected in ΔswnK-ACP, indicating that the swnK gene promotes SW synthesis in A. oxytropis OW 7.8. 8 differentially expressed genes (DEGs) and 7 differentially expressed metabolites (DEMs) closely associated with SW biosynthesis were identified in the transcriptome and metabolome analysis of A. oxytropis OW 7.8 and ΔswnK-ACP. The SW biosynthesis pathway in A. oxytropis OW 7.8 was predicted and refined. These results may lay foundation of in-depth analysis of the molecular mechanisms and metabolic pathway of SW synthesis in fungi, and provide reference for future control of SW in locoweed, which would benefit the development of grassland animal husbandry and the sustainable use of grassland ecosystem.