title: Fgk3 glycogen synthase kinase is important for development, pathogenesis, and stress responses in Fusarium graminearum.
abstract: Wheat scab caused by Fusarium graminearum is an important disease. In a previous study, the FGK3 glycogen synthase kinase gene orthologous to mammalian GSK3 was identified as an important virulence factor. Although GSK3 orthologs are well-conserved, none of them have been functionally characterized in fungal pathogens. In this study, we further characterized the roles of FGK3 gene. The Δfgk3 mutant had pleiotropic defects in growth rate, conidium morphology, germination, and perithecium formation. It was non-pathogenic in infection assays and blocked in DON production. Glycogen accumulation was increased in the Δfgk3 mutant, confirming the inhibitory role of Fgk3 on glycogen synthase. In FGK3-GFP transformants, GFP signals mainly localized to the cytoplasm in conidia but to the cytoplasm and nucleus in hyphae. Moreover, the expression level of FGK3 increased in response to cold, H2O2, and SDS stresses. In the Δfgk3 mutant, cold, heat, and salt stresses failed to induce the expression of the stress response-related genes FgGRE2, FgGPD1, FgCTT1, and FgMSN2. In the presence of 80 mM LiCl, a GSK3 kinase inhibitor, the wild type displayed similar defects to the Δfgk3 mutant. Overall, our results indicate that FGK3 is important for growth, conidiogenesis, DON production, pathogenicity, and stress responses in F. graminearum.
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Qin
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China.
authors.forename: Guanghui
authors.initials: G
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China.
authors.forename: Cong
authors.initials: C
authors.lastname: Jiang
authors.affiliation: Department of Botany and Plant Pathology, Purdue University, USA.
authors.forename: Jin-Rong
authors.initials: JR
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China.
authors.forename: Chenfang
authors.initials: C
authors.lastname: Wang
mesh_terms: D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D005656:Fungal Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D005670:Fusarium / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000633:toxicity; D025301:Hyphae / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D018021:Lithium Chloride / Q000633:toxicity; D009154:Mutation; D010935:Plant Diseases / Q000382:microbiology; D012492:Salts / Q000494:pharmacology; D013172:Spores, Fungal / Q000187:drug effects; D013696:Temperature; D014255:Trichothecenes / Q000378:metabolism; D014908:Triticum / Q000382:microbiology
chemical_list: D005656:Fungal Proteins; D012492:Salts; D014255:Trichothecenes; D006861:Hydrogen Peroxide; D038362:Glycogen Synthase Kinase 3; D018021:Lithium Chloride; C007262:deoxynivalenol