FoG4MAT Is a New Virulence Factor in Fusarium oxysporum also Involved in Growth, Differentiation, and Sporulation

The gene Bcin04g03490 has been shown to control development and pathogenicity in the plant necrotroph Botrytis cinerea. We have identified the orthologous gene in two formae speciales of the Fusarium oxysporum species complex; it maps to chromosome 7 in the core genome of the lycopersici forma specialis. It encodes a protein with two distinct domains, a GAL4-like Zn(II)2Cys6 binuclear cluster DNA-binding domain and an acetyltransferase domain, as previously shown in B. cinerea. Null mutants were generated in both formae speciales (phaseoli and lycopersici), and the phenotypes exhibited during in culture growth and plant colonization were analyzed. The results obtained demonstrate that this virulence factor is required for complete colonization of the plant host stem vascular tissue and full virulence in F. oxysporum but not for the initial stages of root colonization. In addition, null mutants showed a severe alteration in the formation of aerial mycelia and a drastic reduction of sporulation. These observations are consistent with a master role of FoG4MAT in the gene regulation of different processes crucial for normal development and full disease induction in the plant host.