title: Involvement of the osmosensor histidine kinase and osmotic stress-activated protein kinases in the regulation of secondary metabolism in Fusarium graminearum.
abstract: Fusarium graminearum produces trichothecenes in aerial hyphae, a process which is markedly suppressed by NaCl without a significant effect on fungal growth. Here we report on the involvement of kinases of the two-component osmotic signal transduction pathway in the regulation of secondary metabolism in F. graminearum. While a deletion null mutant of FgOs1 (encoding the osmosensor histidine kinase) (deltaFgOs1) produced a reduced amount of the red pigment aurofusarin and was unaltered in its ability to produce trichothecenes, deletion null mutants of FgOs4 (encoding mitogen-activated protein kinase kinase kinase; MAPKKK), FgOs5 (MAPKK), and FgOs2 (MAPK) showed markedly enhanced pigmentation and failed to produce trichothecenes in aerial hyphae. Also, the transcript levels of PKS12 and GIP2 (aurofusarin biosynthetic pathway and regulatory genes, respectively) were significantly enhanced in the deltaFgOs4, deltaFgOs5, and deltaFgOs2 mutants and were reduced in the deltaFgOs1 mutant. In addition, expression of Tri4 and Tri6 (trichothecene biosynthetic pathway and regulatory genes) and production of trichothecenes in rice medium were markedly reduced in the former three protein kinase mutants. This is the first report demonstrating the involvement of a MAPK in the regulation of secondary metabolism.
authors: Plant & Microbial Metabolic Engineering Research Unit, Discovery Research Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors: Noriyuki
authors: N
authors: Ochiai
authors: Takeshi
authors: T
authors: Tokai
authors: Takumi
authors: T
authors: Nishiuchi
authors: Naoko
authors: N
authors: Takahashi-Ando
authors: Makoto
authors: M
authors: Fujimura
authors: Makoto
authors: M
authors: Kimura
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology; D015152:Blotting, Northern; D025141:Drug Resistance, Fungal; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005670:Fusarium / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D005838:Genotype; D000071677:Histidine Kinase; D020930:MAP Kinase Kinase Kinases / Q000235:genetics / Q000378:metabolism; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D009154:Mutation; D009183:Mycotoxins / Q000378:metabolism; D009285:Naphthoquinones / Q000378:metabolism; D009995:Osmosis; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D014255:Trichothecenes / Q000378:metabolism
chemical_list: D000935:Antifungal Agents; D005656:Fungal Proteins; D009183:Mycotoxins; D009285:Naphthoquinones; D014255:Trichothecenes; D011494:Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D020930:MAP Kinase Kinase Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; D000071677:Histidine Kinase; C083578:aurofusarin