Legacy effects of drought and forest fires on energy metabolism and defence mechanisms

Background

Plant stress response will be assessed according to a triphasic stress model (Kranner et al. 2010): an "alarm phase" (stress perception via the signalling network) activates stress response systems, followed by "resistance" (functional protection and repair systems) and then "exhaustion" (failure of protection and repair mechanisms). As yet, the molecular mechanisms that cause a switch from neutral or beneficial "eustress" to detrimental "distress" are poorly understood. Generally, there is a lack of field studies, and this project will provide deep insights into plant response to drought and fire, far beyond the Arabidopsis and crops models available so far.

Hypothesis

Recurrent droughts and sub-lethal fire damage have legacy effects on the signalling network of hormones and redox-active compounds, with downstream effects on energy metabolism and molecular protection mechanisms (e.g., antioxidants, pathogen defence), enabling acclimation (eustress) or leading to deteriorating plant health (distress).

Approach and methods

In evergreen and deciduous tree species (see Dissertation Project 1-1) responses to a) a one-off drought, b) a subsequent drought event, c) multiple recurrent droughts and d) fire damage will be analyzed using a powerful combination of targeted analyses (UHPLC-MS/MS, UHPLC) with an untargeted GC-MS-based metabolomics approach. The project is expected to provide deep insights into the effects of a) to d) on energy metabolism (untargeted metabolite profiling and photosynthetic pigments), and signaling and protective compounds (antioxidants, hormones, phenolic compounds), also benefitting from knowledge on fungal associations generated in project 1-4.

Time frame