A tale of two genes: The role of transcription factors ftf1 and ftf2 in fungal growth and pathogenicity

SCAN Seminar

Title: A tale of two genes: The role of transcription factors ftf1 and ftf2 in fungal growth and pathogenicity

Speaker: José J. de Vega-Bartol

Affiliation: Laboratory Forest Biotech

Abstract:

The gene ftf2, that encodes a transcription factor with a Zn(II)2-Cys6 binuclear cluster DNA-binding motif, is found in pathogenic and non-pathogenic fungi. In order to clarify its function, silencing of ftf2 was induced in non-pathogenic strains of F. oxysporum as well as in virulent strains of F. oxysporum f.sp. phaseoli by Agrobacterium tumefaciens mediated transfer of a hairpin-expression vector carrying fragments of the target gene. Next, the expression of ftf2 was analyzed in non-pathogenic and pathogenic wild-type strains, both in planta and in culture. Finally, the ftf2-regulated genes were identified by SSH and their expression analysed. Results showed ftf2 is a constitutive gene apparently involved in nutritional metabolism. Remarkably, a multicopy gene highly homologous to ftf2, called ftf1, was found only in highly virulent strains and, by contrast to ftf2, a dramatic upregulation during early stages of infection of the host plant was observed. Gene ftf1 is a virulence gene like demonstrated by ftf1 RNAi silencing followed by infection assays on tomato and bean plants, and the probed relation between virulence and ftf1 expression in wild-type strains. The high homology between ftf1 and ftf2 but their different role poses questions on gene evolution that may be of interest in unraveling how pathogenic strains have evolved from non pathogenic ones and on the origin of pathogens specialization.