Fenhexamid - an efficient and inexpensive fungicide for selection of Magnaporthe oryzae transformants

Abstract

Magnaporthe oryzae is one of the most economically important phytopathogenic fungi, and is used as a model organism to study plant-pathogen interactions. To unravel the infection process, forward and reverse genetic approaches are essential, but are often hindered by the lack of a straightforward selection procedure for transformants. Here we report on the use of fenhexamid, an inhibitor of ergosterol biosynthesis, for selection of M. oryzae transformants. An allele of the sterol 3-ketoreductase gene of Fusarium fujikuroi (FfERG27), known to confer resistance to fenhexamid, has already been used successfully with transformants of Botrytis cinerea. Our results demonstrate that expression of the FfERG27 allele in M. oryzae also enables highly efficient selection of transformants on fenhexamid-containing media. The use of fenhexamid is an inexpensive alternative for selection as compared to commonly used antibiotics like hygromycin. No impact on growth and infection phenotypes of fenhexamid resistant M. oryzae mutants was detected, which underpins its usefulness for selecting M. oryzae transformants.