MAPKK FgMkk1 of Fusarium graminearum regulates vegetative differentiation, multiple stress response, and virulence via the cell wall integrity and high‐osmolarity glycerol signaling pathways

• Published in: Environmental microbiology Vol. 16; no. 7; pp. 2023 - 2037
• Main Authors: Yun, Yingzi, Liu, Zunyong, Zhang, Jingze, Shim, Won‐Bo, Chen, Yun, Ma, Zhonghua
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Science 01.07.2014; Blackwell Publishing Ltd; Blackwell; Wiley Subscription Services, Inc
• Subjects: Animal, plant and microbial ecology; Biological and medical sciences; Biological control; Biological Control Agents; Biosynthesis; Cell Wall; Cell Wall - genetics; Cell Wall - metabolism; cell walls; conidiation; Crop diseases; deficiency; deoxynivalenol; drug effects; fludioxonil; Fundamental and applied biological sciences. Psychology; Fungal Proteins; Fungal Proteins - genetics; Fungal Proteins - metabolism; Fungicides; Fungicides, Industrial; Fusarium; Fusarium - drug effects; Fusarium - genetics; Fusarium - metabolism; Fusarium - pathogenicity; Fusarium graminearum; Gene Deletion; Gene Expression Regulation, Fungal; General aspects; genetics; Gibberella zeae; Glycerol; Glycerol - metabolism; head blight; hyphae; Hyphae - drug effects; Hyphae - genetics; Hyphae - metabolism; Hyphae - pathogenicity; Hypocrea atroviride; iprodione; Kinases; metabolism; Microbial ecology; Microbiology; Miscellaneous; mitogen-activated protein kinase; mitogen-activated protein kinase kinase; Mitogen-Activated Protein Kinase Kinases; Mitogen-Activated Protein Kinase Kinases - deficiency; Mitogen-Activated Protein Kinase Kinases - genetics; mutants; Mycology; Osmolar Concentration; Osmotic Pressure; Oxidative stress; pathogenicity; Pathogens; Phosphorylation; Pigmentation; Plant Diseases; Plant Diseases - microbiology; Signal Transduction; Stress response; transcription factors; Trichoderma; Trichoderma - pathogenicity; Trichoderma atroviride; Triticum; Triticum - microbiology; Triticum aestivum; Virulence; Western blotting; wheat; Yeasts; Fungi; Regulation(control); Fusarium graminearum; Virulence; Glycerol; Fungi Imperfecti; Differentiation; Cell wall; Stress
• ISSN: 1462-2912; 1462-2920; 1462-2920
• DOI: 10.1111/1462-2920.12334

Mitogen‐activated protein (MAP) kinases play crucial roles in regulating fungal development, growth and pathogenicity, and in responses to the environment. In this study, we characterized a MAP kinase kinase FgMkk1 in Fusarium graminearum, the causal agent of wheat head blight. Phenotypic analyses of the FgMKK1 mutant (ΔFgMKK1) showed that FgMkk1 is involved in the regulation of hyphal growth, pigmentation, conidiation, deoxynivalenol biosynthesis and virulence of F. graminearum. ΔFgMKK1 also showed increased sensitivity to cell wall‐damaging agents, and to osmotic and oxidative stresses, but exhibited decreased sensitivity to the fungicides iprodione and fludioxonil. In addition, the mutant revealed increased sensitivity to a biocontrol agent, Trichoderma atroviride. Western blot assays revealed that FgMkk1 positively regulates phosphorylation of the MAP kinases Mgv1 and FgOs‐2, the key component in the cell wall integrity (CWI) and high‐osmolarity glycerol (HOG) signalling pathway respectively. Yeast two‐hybrid assay indicated that Mgv1 interacts with a transcription factor FgRlm1. The FgRLM1 mutant (ΔFgRLM1) showed increased sensitivity to cell wall‐damaging agents and exhibited decreased virulence. Taken together, our data indicated that FgMkk1 is an upstream component of Mgv1, and regulates vegetative differentiation, multiple stress response and virulence via the CWI and HOG signalling pathways. FgRlm1 may be a downstream component of Mgv1 in the CWI pathway in F. graminearum.