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The MAPKK FgMkk1 of F usarium graminearum regulates vegetative differentiation, multiple stress response, and virulence via the cell wall integrity and high‐osmolarity glycerol signaling pathways
Author(s) -
Yun Yingzi,
Liu Zunyong,
Zhang Jingze,
Shim WonBo,
Chen Yun,
Ma Zhonghua
Publication year - 2014
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.12334
Subject(s) - biology , conidiation , virulence , mutant , kinase , microbiology and biotechnology , fungal protein , biochemistry , gene
Summary 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 F usarium 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, T richoderma 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 .