Identification and characterization of cell wall integrity monitoring components in plants

• Applicant: Dr. Timo Engelsdorf
• Subject Area: Plant Physiology
• Term: from 2013 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 246277104

Functional integrity of plant cell walls has to be maintained enabling them to perform their functions during development and defence against biotic and abiotic stress. This functional integrity is influenced by cell wall composition, structure and cellular metabolism. Recent studies have shown that cell wall damage (CWD) impairing functional integrity is being detected in plants and specific compensatory reactions are initiated to maintain integrity. These reactions involve changes in cell wall composition and structure, in production of phytohormones and in carbohydrate metabolism. In particular the effects on carbohydrate metabolism are sensitive to manipulation by osmotica. The host lab has established an Arabidopsis seedling-based model system to study the mode of action of the CWD response mechanism. In the context of this fellowship I aim to execute two subprojects. First, I will characterize gene functions necessary for CWD-induced compensatory reactions. Based on transcriptional and preliminary phenotypic data collected in the host lab, several candidate genes have already been implicated in cell wall metabolism and the response to CWD. I will confirm these preliminary results and extend them specifically with respect to detailed cell wall analyses and the effect on resistance towards cell wall penetrating fungal pathogens in gene knockouts to determine biological functions of candidate genes. The second subproject will focus on the identification and characterization of early signalling components of the CWD response. It has already been shown that CWD induces post-translational protein modification. Furthermore, the putative stretch-activated Ca2+ channel MCA1 is required for the osmosensitive components of the CWD response. Therefore I will analyse the impact of CWD and osmotic support on the phosphoproteome of wild type and mca1 seedlings in order to identify proteins that are post-translationally modified in response to CWD in an osmosensitive way. I will then use knockout lines for the candidate genes to investigate their function in CWD response and particularly in carbohydrate partitioning. The aims of this project are locating it at the intersection between plant physiology, cell biology and phytopathology and therefore, novel insights regarding the cell wall integrity maintenance mechanism will be relevant for all three areas. New insights in turgor-dependent regulatory processes will also strengthen the link between biophysical and biochemical research.

• DFG Programme: Research Fellowships
• International Connection: Norway, USA
• Participating Institution: University of California, Berkeley ; Energy and Biosciences Institute
• Host: Professor Dr. Thorsten Hamann