FpGlr1 is essential for normal growth and redox homeostasis in F. pseudograminearum. Deletion of FpGlr1 disrupts DON biosynthesis and reduces fungal virulence. FpGlr1 coordinates oxidative stress response and host infection processes. Glutathione reductase plays a crucial role in maintaining redox homeostasis and coordinating growth, development, and secondary metabolism in pathogenic fungi. However, its function in the wheat crown rot pathogen Fusarium pseudograminearum remains unclear. In this study, the glutathione reductase gene FpGlr1 was functionally characterized through targeted gene deletion. Compared with the wild-type strain, the Δ FpGlr1 mutant exhibited significantly reduced vegetative growth and asexual reproduction, accompanied by abnormal increases in conidial septation. In addition, the mutant showed enhanced sensitivity to multiple fungicides, including fluazinam, carbendazim, tebuconazole, and pyraclostrobin. The Δ FpGlr1 mutant also displayed increased sensitivity to Fe 2+ and menadione, along with impaired antioxidant capacity, elevated lipid peroxidation, and accumulation of oxidized glutathione. Deletion of FpGlr1 markedly reduced virulence during host infection and completely abolished the ability to penetrate cellophane. Moreover, the mutant produced significantly lower levels of deoxynivalenol (DON) and exhibited defective toxisome formation, accompanied by downregulation of trichothecene biosynthetic ( TRI ) genes. Transcriptomic analysis revealed that differentially expressed genes in the Δ FpGlr1 mutant were significantly enriched in glutathione metabolism and carbohydrate metabolism related pathways. Consistently, metabolomic profiling demonstrated extensive metabolic reprogramming, particularly affecting carbohydrate, amino acid, energy, and purine metabolism, and revealed a decoupling between transcriptional activation and metabolite accumulation in key sugar metabolic pathways. Collectively, these findings demonstrate that FpGlr1 is essential for oxidative stress responses, secondary metabolism, and virulence in F. pseudograminearum , highlighting its importance in redox regulation and its potential as a target for controlling wheat crown rot.
Zhang et al. (Wed,) studied this question.