scholarly journals The Mitogen-Activated Protein Kinase CgMK1 Governs Appressorium Formation, Melanin Synthesis, and Plant Infection of Colletotrichum gloeosporioides

2017 ◽  
Vol 8 ◽  
Author(s):  
Puhuizhong He ◽  
Yonglin Wang ◽  
Xiaolian Wang ◽  
Xiaolin Zhang ◽  
Chengming Tian
Keyword(s):  
Protein Kinase ◽  
Colletotrichum Gloeosporioides ◽  
Mitogen Activated Protein Kinase ◽  
Melanin Synthesis ◽  
Appressorium Formation ◽  
Plant Infection ◽  
Mitogen Activated Protein

scholarly journals Requirement of a Mitogen-Activated Protein Kinase for Appressorium Formation and Penetration of Insect Cuticle by the Entomopathogenic Fungus Beauveria bassiana

2010 ◽  
Vol 76 (7) ◽  
pp. 2262-2270 ◽  
Author(s):  
Yongjun Zhang ◽  
Jianqing Zhang ◽  
Xiaodong Jiang ◽  
Guijiang Wang ◽  
Zhibing Luo ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Beauveria Bassiana ◽  
Molecular Mechanisms ◽  
Cell Surface Hydrophobicity ◽  
Mitogen Activated Protein Kinase ◽  
Insect Cuticle ◽  
Wild Type ◽  
Appressorium Formation ◽  
Mitogen Activated Protein ◽  
Ssh Library

ABSTRACT Beauveria bassiana is an important insect-pathogenic fungus that invades insects by direct penetration of the host cuticle. To delineate the molecular mechanisms involved in fungal infection, a mitogen-activated protein kinase (MAPK) gene, Bbmpk1, which encodes a YERK1 family MAPK was isolated and characterized. Targeted gene disruption of Bbmpk1 resulted in a complete loss of virulence when applied topically to host insects but did not affect growth of the fungus when conidia were injected directly into the hemocoel. Hyphae of the mutant strain growing in the insect hemocoel were unable to penetrate the cuticle growing outwards and consequently failed to sporulate on the cadaver surface. These data suggest that BbMPK1 is essential for penetration of the insect cuticle both from the outside and from the inside-out in order to escape and disperse from the host. Inactivation of BbMPK1 also caused a significant decrease in fungal adhesion to insect cuticles and eliminated their ability to form appressoria. In order to identify downstream genes regulated by BbMPK1, a suppressive subtractive hybridization (SSH) library was generated comparing mutant and wild-type transcripts isolated during appressorium formation. Thirty-one genes screened from the SSH library were determined to be expressed in the wild-type strain but either significantly reduced or not expressed in the mutant. Ten genes showed high or medium similarity to known protein encoding genes, including proteins involved in cell surface hydrophobicity, lipid metabolism, microtubule dynamics, mitochondrial electron transport, chromatin remodeling, transcription, rRNA processing, small nucleolar RNA accumulation, oxidation of aldehydes, translation, and likely other cellular processes.

scholarly journals The Mitogen-Activated Protein Kinase Gene MAF1 Is Essential for the Early Differentiation Phase of Appressorium Formation in Colletotrichum lagenarium

2002 ◽  
Vol 15 (12) ◽  
pp. 1268-1276 ◽  
Author(s):  
Kaihei Kojima ◽  
Taisei Kikuchi ◽  
Yoshitaka Takano ◽  
Eriko Oshiro ◽  
Tetsuro Okuno
Keyword(s):  
Protein Kinase ◽  
Mitogen Activated Protein Kinase ◽  
Nutrient Agar ◽  
Wild Type ◽  
Appressorium Formation ◽  
Colletotrichum Lagenarium ◽  
Early Differentiation ◽  
Mitogen Activated Protein ◽  
Germ Tubes ◽  
Mapk Gene

Colletotrichum lagenarium, the causal agent of cucumber anthracnose, invades host plants by forming a specialized infection structure called an appressorium. In this fungus, the mitogen-activated protein kinase (MAPK) gene CMK1 is involved in several steps of the infection process, including appressorium formation. In this study, the goal was to investigate roles of other MAPKs in C. lagenarium. The MAPK gene MAF1, related to Saccharomyces cerevisiae MPK1 and Magnaporthe grisea MPS1, was isolated and functionally characterized. The maf1 gene replacement mutants grew normally, but there was a significant reduction in conidiation and fungal pathogenicity. The M. grisea mps1 mutant forms appressoria, but conidia of the C. lagenarium maf1 mutants produced elongated germ tubes without appressoria on both host plant and glass, on which the wild type forms appressoria, suggesting that MAF1 has an essential role in appressorium formation on inductive surfaces. On a nutrient agar, wild-type conidia produced elongated germ tubes without appressoria. The morphological phenotype of the wild type on the nutrient agar was similar to that of the maf1 mutants on inductive surfaces, suggesting repression of the MAF1-mediated appressorium differentiation on the nutrient agar. The cmk1 mutants failed to form normal appressoria but produced swollen, appressorium-like structures on inductive surfaces, which is morphologically different from the maf1 mutants. These findings suggest that MAF1 is required for the early differentiation phase of appressorium formation, whereas CMK1 is involved in the maturation of appressoria.

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