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Signaling by the pathogenicity-related MAP kinase of Cochliobolus heterostrophus correlates with its local

Sophie Lev1, Hila Tal, Mark S Rose

  • 1Department of Biology, Technion-Israel Institute of Technology, Haifa Israel.

Molecular Plant-Microbe Interactions : MPMI
|August 7, 2009
PubMed

Insights

In Cochliobolus heterostrophus, the pathogenicity mitogen-activated protein kinase (MAPK) Chk1 accumulates in appressoria, but its phosphorylation level doesn't significantly change during this key developmental process.

Area of Science:

  • Fungal Pathogenesis
  • Molecular Biology
  • Signal Transduction

Background:

  • Mitogen-activated protein kinases (MAPKs) are crucial signaling molecules.
  • MAPK activity is regulated by phosphorylation, concentration, and localization.
  • The fungal MAPK Chk1 is essential for virulence and development in Cochliobolus heterostrophus.

Purpose of the Study:

  • To investigate the regulation and localization of the pathogenicity MAPK Chk1 in Cochliobolus heterostrophus.
  • To determine how Chk1 activation correlates with developmental processes like appressoria formation.

Main Methods:

  • Tracking CHK1 transcript and protein levels using Chk1-GFP fusion.
  • Analyzing protein localization via fluorescence microscopy.
  • Monitoring downstream gene expression.
  • Assessing Chk1 phosphorylation under various stress conditions.

Main Results:

  • Chk1-GFP localized to ungerminated conidia, maturating appressoria, and appressorial nuclei.
  • Chk1-dependent genes were upregulated during appressoria formation.
  • Chk1 protein quantity and phosphorylation showed minimal changes during appressoria development.
  • Temperature shifts and hyperosmotic stress altered Chk1 phosphorylation levels.

Conclusions:

  • Chk1 activation during appressoria formation in C. heterostrophus is primarily mediated by its accumulation in specific cellular compartments.
  • Significant changes in Chk1 phosphorylation are not the main mechanism for its activation during this developmental stage.
  • Environmental stresses can modulate Chk1 phosphorylation, suggesting a role in stress response pathways.

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