Fluorescence Assisted Selection of Transformants (FAST): Using flow cytometry to select fungal transformants

The availability of drug resistance markers for fungal transformation is often a limiting factor in both fungal genetics research and industrial applications. We describe a new technique using flow cytometry to select fungal transformants using well-known fluorescent proteins as markers for transformation. This new technique, Fluorescence-Assisted Selection of Transformants (FAST), was used for a transformation of Fusarium oxysporum with GFP as a marker targeted at a specific site on chromosome 14. The resulting strain was then transformed again with a gene replacement construct containing both RFP and a gene for drug resistance as markers. By directly comparing FAST with drug resistance selection we show that both methods yield comparable numbers of gene deletion mutants.