Phospholipid homeostasis plays an important role in fungal development, fungicide resistance and virulence in Fusarium graminearum

Phospholipids are major structural components of all cell membranes and participate in energy storage, signal transduction and environmental adaptability in eukaryotes. To date, the enzymes involved in phospholipid biosynthesis have been well characterized in budding yeast. However, their functions in filamentous fungi are largely unclear, especially their contribution to the interaction between phytopathogenic filamentous fungi and plants. In this study, we identified 10 phospholipid biosynthesis-related genes and genetically analyzed their functions in the Fusarium head blight pathogen Fusarium graminearum. The results of this study indicate that phosphatidylethanolamine (PE) and phosphatidylcholine (PC) are critical for fungal vegetative growth. The biosynthesis of PE and PC is largely dependent on FgPsd2, FgCho2 and FgOpi3 in the de novo pathway of phospholipid biosynthesis in F. graminearum. Phospholipid biosynthetic gene mutants showed abnormal conidiation, increased sensitivity to fungicides and the oxidative stress agent H2O2, and defective endocytosis, especially the Delta Fgpsd2, Delta Fgcho2 and Delta Fgopi3 mutants. Importantly, this study shows for the first time that the de novo pathway of phospholipid biosynthesis is required for mycotoxin production and full virulence in plant pathogenic fungi.