title: FgFlbD regulates hyphal differentiation required for sexual and asexual reproduction in the ascomycete fungus Fusarium graminearum.
abstract: Fusarium graminearum is a filamentous fungal plant pathogen that infects major cereal crops. The fungus produces both sexual and asexual spores in order to endure unfavorable environmental conditions and increase their numbers and distribution across plants. In a model filamentous fungus, Aspergillus nidulans, early induction of conidiogenesis is orchestrated by the fluffy genes. The objectives of this study were to characterize fluffy gene homologs involved in conidiogenesis and their mechanism of action in F. graminearum. We characterized five fluffy gene homologs in F. graminearum and found that FlbD is the only conserved regulator for conidiogenesis in A. nidulans and F. graminearum. Deletion of fgflbD prevented hyphal differentiation and the formation of perithecia. Successful interspecies complementation using A. nidulans flbD demonstrated that the molecular mechanisms responsible for FlbD functions are conserved in F. graminearum. Moreover, abaA-wetA pathway is positively regulated by FgFlbD during conidiogenesis in F. graminearum. Deleting fgflbD abolished morphological effects of abaA overexpression, which suggests that additional factors for FgFlbD or an AbaA-independent pathway for conidiogenesis are required for F. graminearum conidiation. Importantly, this study led to the construction of a genetic pathway of F. graminearum conidiogenesis and provides new insights into the genetics of conidiogenesis in fungi.
authors.affiliation: Department of Agricultural Biotechnology and Center for Fungal Pathogenesis, Seoul National University, Seoul, 151-921, Republic of Korea.
authors.forename: Hokyoung
authors.initials: H
authors.lastname: Son
authors.forename: Myung-Gu
authors.initials: MG
authors.lastname: Kim
authors.forename: Suhn-Kee
authors.initials: SK
authors.lastname: Chae
authors.forename: Yin-Won
authors.initials: YW
authors.lastname: Lee
mesh_terms: D001233:Aspergillus nidulans / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D005670:Fusarium / Q000235:genetics* / Q000502:physiology; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D025301:Hyphae / Q000235:genetics / Q000254:growth & development*; D012100:Reproduction, Asexual; D013172:Spores, Fungal / Q000235:genetics / Q000254:growth & development*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D014157:Transcription Factors