The function of the alternative oxidase gene in the tolerance of Fusarium graminearum to azoxystrobin

Fusarium graminearum is responsible for Fusarium head blight in wheat, resulting in considerable economic losses in grain production. Controlling F. graminearum requires elucidating the biological functions of key genes associated with growth and mycotoxin biosynthesis. In this study, the alternative oxidase inhibitor propyl gallate (PG) was found to markedly reduce the tolerance of F. graminearum PH-1 to azoxystrobin (AZ), indicating that alternative oxidase (AOX) is essential for AZ resistance in F. graminearum. The biological functions of FgAOX were further investigated by comparing biochemical and transcriptomic changes between the FgAOX deletion mutant and wild-type F. graminearum PH-1. Compared to the PH-1, the FgAOX deletion mutant showed reduced conidial production, thickened septa, and increased deoxynivalenol accumulation, and enhanced the sensitivity to AZ. Transcriptomic analysis revealed that FgAOX is involved in regulating energy metabolism, oxidative stress response, and secondary metabolite biosynthesis. Deletion of FgAOX triggered a reprogramming of energy metabolism, affecting the TCA cycle, glycolysis/gluconeogenesis, and lipid metabolism, ultimately leading to enhanced ATP synthesis. Consequently, Reactive Oxygen Species levels increased, and the expression of genes related to antioxidant Enzymes and redox processes was significantly altered, disrupting cellular redox homeostasis. These findings highlight the important role of FgAOX in the AZ resistance as well as vegetative growth, toxin production, oxidative stress response, and energy metabolism of F. graminearum, providing insights for potential disease management strategies.

Alternative oxidase; Azoxystrobin; Drug resistance; Fusarium graminearum; Transcriptome analysis.