Fphog1, a HOG-type MAP kinase gene, is involved in multistress response in Fusarium proliferatum

• Published in: Journal of basic microbiology Vol. 48; no. 3; pp. 151 - 159
• Main Authors: Ádám, Attila L, Kohut, Gábor, Hornok, László
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley-VCH Verlag 01.06.2008; WILEY-VCH Verlag; WILEY‐VCH Verlag
• Subjects: Apoptosis; conidia; DNA Fragmentation; DNA, Fungal - isolation & purification; Fusarium; Fusarium - enzymology; Fusarium - genetics; Fusarium - physiology; Fusarium proliferatum; Gene Expression Regulation, Fungal; gene targeting; genes; Genes, Fungal; germination; heat; HOG-type mitogen-activated protein kinase; Homeostasis; Hot Temperature; hydrogen peroxide; Hydrogen Peroxide - metabolism; Hyperosmotic stress; membrane permeability; mitochondrial membrane; Mitochondrial Membranes - physiology; mitogen-activated protein kinase; Mitogen-Activated Protein Kinases - genetics; Mitogen-Activated Protein Kinases - physiology; mortality; mutants; Osmotic Pressure; osmotic stress; Permeability; phenotype; Polymerase Chain Reaction; Programmed cell death; quantitative polymerase chain reaction; Reactive Oxygen Species - metabolism; Saccharomyces cerevisiae; Salt stress; Sodium Chloride - metabolism; sorbitol; Sorbitol - metabolism; Spores, Fungal - physiology; transcription (genetics); Transformation, Genetic; Ultraviolet Rays
• ISSN: 0233-111X; 1521-4028
• DOI: 10.1002/jobm.200700403

ΔFphog1 mutants of Fusarium proliferatum obtained by targeted gene disruption of Fphog1, an orthologue of the Saccharomyces cerevisiae hog1 MAPK gene showed increased sensitivity towards different abiotic stressors including UV-irradiation, heat, salt, osmotic and hydrogen peroxide treatments. Incubation of the ΔFphog1 mutants under hyperosmotic conditions was accompanied with prolonged growth arrest, inhibition of conidial germination, morphological abnormalities and time-dependent increase of the cell death rate. The wild type Fphog1 gene, under the control of its own promoter, was able to rescue the multistress sensitivity of the mutant strain. Real time qPCR data demonstrated that under salt and sorbitol stress conditions the Fphog1 gene is not subject of transcriptional regulation. Levels of reactive oxygen species (ROS), mitochondrial membrane permeability transition, nuclear disintegration and DNA fragmentation, indicators of programmed cell death (PCD) all showed significant increases under osmotic stress conditions in the ΔFphog1 mutant in comparison to the wild type strain. These results suggest that an important function of Fphog1 is attenuating apoptotic phenotypes under salt and sorbitol stressors. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)