title: Functional analyses of individual mating-type transcripts at MAT loci in Fusarium graminearum and Fusarium asiaticum.
abstract: Members of the Fusarium graminearum species (Fg) complex, which are homothallic ascomycetous species, carry two opposite mating-type (MAT) loci in a single nucleus for controlling sexual development. We investigated the roles of three (MAT1-1-1, MAT1-1-2, and MAT1-1-3) and two (MAT1-2-1 and MAT1-2-3) transcripts located at both loci in representative Fg complex species (F. graminearum and Fusarium asiaticum). In self-fertile F. graminearum strains, the transcript levels of MAT1-1-1, MAT1-2-1, and MAT1-2-3 peaked 2 days after sexual induction (dai) and then remained high until 12 dai, whereas MAT1-1-2 and MAT1-1-3 transcripts reached peak levels between 4 and 8 dai. In contrast, all of the MAT transcripts in self-sterile F. asiaticum strains accumulated at much lower levels than those in F. graminearum during the entire time. Targeted gene deletions confirmed that MAT1-1-1, MAT1-1-2, MAT1-1-3, and MAT1-2-1 were essential for self-fertility in F. graminearum, but MAT1-2-3 was not. All MAT-deleted strains (except ΔMAT1-2-3) produced recombinant perithecia when outcrossed to a self-fertile strain. These results indicate that developmental up-regulation of the individual MAT genes in both a proper fashion and quantity is critical for sexual development, and that alterations in the gene expression could be attributed to the variation in self-sterility among the Fg complex.
authors.affiliation: Department of Medical Biotechnology, Soonchunhyang University, Asan, South Korea.
authors.forename: Hee-Kyoung
authors.initials: HK
authors.lastname: Kim
authors.forename: Eun Ji
authors.initials: EJ
authors.lastname: Cho
authors.forename: Seunghoon
authors.initials: S
authors.lastname: Lee
authors.forename: Young-Sang
authors.initials: YS
authors.lastname: Lee
authors.forename: Sung-Hwan
authors.initials: SH
authors.lastname: Yun
mesh_terms: D005670:Fusarium / Q000235:genetics* / Q000254:growth & development*; D017353:Gene Deletion; D020869:Gene Expression Profiling; D005800:Genes, Fungal; D049770:Genes, Mating Type, Fungal; D013997:Time Factors; D014158:Transcription, Genetic