Deletion of FgSRE1 Impairs Reproduction and Virulence of Fusarium graminearum and Alters Metabolic and Membrane-Transport Gene Expression

Abstract

Fusarium graminearum, the major pathogen causing maize ear rot, severely threatens food security. Targeted gene deletion was used to characterize physiological functions of FgSRE1 in this pathogen. Transcriptomic profiling was conducted on axenic wild-type and ΔFgSRE1 cultures, plus maize ear tissues colonized by both strains. Nine core DEGs functionally annotated to transmembrane transport, membrane homeostasis and oxidative stress pathways were selected for qRT-PCR validation, including four upregulated genes encoding putative transferases and five downregulated transporter genes. Phenotypic assays revealed that the ΔFgSRE1 mutant displayed severe defects in conidial and ascospore production, along with drastically weakened pathogenicity on maize ears and leaves versus wild-type and complemented strains. qRT-PCR analysis confirmed consistent expression trends with the RNA-seq data: four putative transferase-encoding genes were up-regulated, whereas five genes related to membrane and redox transport were repressed. Together, the genetic and phenotypic results demonstrate that FgSRE1 contributes to reproductive development and virulence in F. graminearum, whereas the transcriptomic data suggest potential associations with metabolic, redox, and membrane-transport-related pathways. Our findings provide a basis for investigating the FgSRE1-associated virulence network and developing eco-friendly maize ear rot control strategies.