Fss1 is involved in the regulation of an ENA5 homologue for sodium and lithium tolerance in Fusarium graminearum

Summary Sodium is an abundant cation required for protein function and maintenance of cellular osmotic homeostasis. High concentrations of sodium are toxic, and fungi have evolved efficient sodium efflux systems. In this study, we characterized a novel sodium tolerance mechanism in the plant pathogen F usarium graminearum . F usarium graminearum sodium sensitive 1 ( Fss1 ) is a nuclear transcription factor with a Zn(II) 2 Cys 6 fungal‐type DNA ‐binding domain required for sodium tolerance. RNA ‐seq and genetic studies revealed that a P ‐type ATPase pump, exitus natru ( L atin: exit sodium) 1 ( FgEna5 ), mediates the phenotypic defects of FSS1 mutants. A homologue of PACC ( PAC1 ) was required for FgEna5 ‐dependent sodium and lithium tolerance independent of Fss1 . The results of this study revealed that F . graminearum has a distinct and novel pathway for sodium tolerance not present in other model fungi.