We have previously reported the isolation of ftf1 (Fopta1a) and ftf2 (Fopta1b), two genes coding for highly homologous transcription factors differentially involved in pathogenicity in F. oxysporum f. sp. phaseoli (Kendrick & Snyder). Both transcription factors contain a Zn(II)-Cys6 binuclear cluster DNA-binding motif and a fungal transcription factor domain. The structural region of both genes share a 80-85% of homology at the nucleotide level; this homology falls to a 70% in the promoter region. The ftf1 gene is present only in highly virulent strains and show a dramatic peak of expression 24 to 48 h after infection of common bean plants (Phaseolus vulgaris L.). On the contrary, ftf2 is present in all tested strains (pathogenic and non-pathogenic) and shows a very low level of expression in vivo and in vitro. We have detected up to four copies of ftf1 in highly virulent strains, while ftf2 is a single copy gene in all the strains tested. Genomic architecture is also different in both genes. Some of the copies of ftf1 show some restriction fragment length polymorphisms, but all of them are closely linked to the only copies of transposon marsu detected in F. oxysporum f.sp. phaseoli. The single copy of ftf2 is located downstream of an homologue of bimB3, a gene involved in coupling DNA replication with mitosis in Aspergillus nidulans.
Full conference title:
23rd Fungal Genetics Conference
- Fungal Genetics Conference 23rd (2002)