Plant Biochemistry and Physiology

External cues (light, heavy metals) and internal processes (photosynthesis) provide information that is used for appropriate regulation of plant metabolism and development. Retrograde signalling denotes signalling pathways originating in the organelles (mitochondrion, plastid) and controlling nuclear gene activity. Presently we focus on the timing of events following the sudden impact of a stress cue. The transfer of low light acclimated plants to 100-fold excess light allows the precise onset of stress. We investigate the molecular events in the order of their incidence and causal dependency, including e.g. metabolic changes, recruitment of mRNA to ribosomes, up-regulaton of transcription factors, transcriptome changes, de novo protein synthesis and metabolic adjustment. This involves the analysis of redox and reactive oxygen-derived signals, but also the crosstalk with calcium and posttranslational modifications such as thiol-/disulfide transitions and phosphorylation/ dephosphorylation cascades.