PCR-based identification of MAT-1 and MAT-2 in the Gibberella fujikuroi species complex

All sexually fertile strains in the Gibberella fujikuroi species complex ar e heterothallic, with individual mating types conferred by the broadly cons erved ascomycete idiomorphs MAT-I and MAT-2, We sequenced both alleles from all eight mating populations, developed a multiplex PCR technique to disti nguish these idiomorphs, and tested it with representative strains from all eight biological species and 22 additional species or phylogenetic lineage s from this species complex. In most cases, either an similar to 800-bp fra gment from MAT-2 or an similar to 200-bp fragment from MAT-I is amplified. The amplified fragments cosegregate with mating type, as defined by sexual cross-fertility, in a cross of Fusarium moniliforme (Fusarium verticillioid es). Neither of the primer pairs amplify fragments from Fusarium species su ch as Fusarium graminearum, Fusarium pseudograminearum, and Fusarium culmor um, which have, or are expected to have, Gibberella sexual stages but are t hought to be relatively distant from the species in the G. fujikuroi specie s complex. Our results suggest that MAT allele sequences are useful indicat ors of phylogenetic relatedness in these and other Fusarium species.