Zinc exerts antifungal activity against Fusarium pseudograminearum by interfering with ROS accumulation regulated by transcription factor FpYap1.

Fusarium pseudograminearum is the causative agent of Fusarium crown rot (FCR) in wheat and barley, a serious soil-borne disease worldwide. The main control method of FCR is the application of chemical fungicides. However, environmental risks are non-negligible. Zinc (Zn) is an important micronutrient in all organisms. Here, we proved that Zn is effective against FCR and its molecular mechanism of action was further explored. Zn can inhibit mycelial growth, conidial formation, and conidial germination of F. pseudograminearum. The effective concentration of Zn against the fungus did not affect wheat growth. Transcriptomic analysis identified 3387 differentially expressed genes (DEGs) under zinc sulfate (ZnSO4) treatment. ZnSO4 could damage the cell wall integrity and impair protein acetylation in F. pseudograminearum. Notably, ZnSO4 could promote superoxide ion (O2 ·-) formation, reduce superoxide dismutase (SOD) activity, which is regulated by the transcription factor FpYap1. FpYap1 is significantly up-regulated in response to ZnSO4, and deletion of FpYap1 leads to increased sensitivity to menadione and ZnSO4. The expression of target genes of FpYap1 including FpAhp1, FpGpx2, FpSod1, and FpSod2 were no longer promoted under ZnSO4 stress, although more reactive oxygen species (ROS) were accumulated. Our findings suggest that Zn is not only a necessary nutritional supplement for plants but also a promising candidate for FCR management. The use of Zn as an alternative to chemical fungicides could provide an environmentally friendly approach to controlling this serious disease.