Development of PCR primers for a new Fusarium oxysporum pathogenic on Paris daisy (Argyranthemum frutescens L.)

The inverse PCR technique was applied to clone genomic DNA flanking insertion sites of sequences homologous to the transposable element Fot1 in the genome of a new pathogenic isolate of Fusarium oxysporum obtained from wilted Argyranthemum frutescens (Paris daisy). Based on the genomic flanking regions, a primer was designed which when paired to a second primer matching the Fot1 sequence allowed detection of this pathogen by PCR. The primer pair Mg5/Mg6 could specifically identify nine tested isolates of F. oxysporum from A. frutescens, when fungal genomic DNA was used as template. Moreover, the primer pair Mg5/Mg6 allowed successful detection of the pathogen in stem and root tissue from asymptomatic plants that were artificially inoculated with a representative isolate of F. oxysporum from A. frutescens.