Multidrug resistance in Mycosphaerella graminicola involves the novel major facilitator superfamily (MFS) transporter gene MgMfs1

Screening of EST libraries from the wheat pathogen Mycosphaerella graminicola led to the identification of MgMfs1, a full length Major Facilitator Superfamily (MFS) gene with high homology to putative toxin transporters involved in virulence. Complementation of a Saccharomyces cerevisiae strain carrying multiple non-functional drug transporter genes, with MgMfs1 resulted in an impressive decrease in sensitivity of S. cerevisiae to a broad range of synthetic and natural toxic compounds. MgMfs1 disruptants of M. graminicola generated by Agrobacterium tumefaciens-mediated transformation showed an increased sensitivity to strobilurin fungicides and to the mycotoxin cercosporin, whereas no reduction in virulence on wheat seedlings could be observed. The results indicate that the encoded protein MgMfs1 is a true multidrug transporter that can function as a determinant of the pathogen in sensitivity and resistance to fungicides, and that might play a role in secretion of mycotoxins.