Prof. Dr. Michael Schroda

3. Dissection of the stress response in Chlamydomonas

Rationale

The insufficient adaptation of many crop plants to environmental stress has a significant impact on crop yield. This problem might be solved by transgenic approaches, given that the underlying mechanisms of protection to stress were understood. A large part of the plant’s stress response is mediated by heat shock transcription factors (HSFs). However, the high complexity of the HSF family in higher plants with at least 21 members has complicated the dissection of the stress response in plants. In contrast, the presence in Chlamydomonas of only one canonical HSF that exhibits all characteristic features of plant class A HSFs, made it attractive to use this alga for studying fundamental principles of the plant stress response.

Aim

To understand the fundamental principles of the heat shock factor dependent stress response in Chlamydomonas

Current state

We have combined pharmaceutical and antisense/RNAi approaches, which have enabled us to establish a working model for the regulation of the stress response in Chlamydomonas (see figure below). In collaboration with Alexander Skupin and Oliver Ebenhöh at the MPI this model has been translated into a mathematical model, which is able to reproduce our data from inhibitor feeding.

Currently addressed questions and approaches

• Is our model of the HSF1-dependent stress response correct?
  → Predictions by the mathematical model are tested experimentally using RNAi, qPCR, pharmaceutical, and quantitative mass spectrometry approaches
• Which genes are regulated by HSF1?
  → In collaboration with Wolfgang Hess at the University of Freiburg we analyse expression profiles of HSF1-RNAi and wild-type strains using Microarrays