Cross-talk between redox, metabolic and hormonal retrograde chloroplast signals in the expressional regulation of nuclear encoded plastid proteins

• Applicant: Professor Dr. Karl-Josef Dietz
• Subject Area: Plant Physiology
• Term: from 2007 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 29017492

Based on the results on regulatory dynamics and involved transcription factors, and also on methods established in the first funding period, the work plan for the second period focuses on characterizing early events in retrograde signaling for metabolic adjustment, particularly during light shift. (i) Time-resolved transcriptional responses in wild type and defined mutants with defects in hormonal, redox and metabolite processes will be used to address components of the signaling and metabolic network. (ii) Retrograde signaling relies on combinatorial signal integration as seen e.g. for several transcription factor transcript level in dependence on light, CO2 and abscisic acid. Thus, the project will investigate the combinatorial effect of photosynthesis-related redox, abscisic acid and metabolite signals in order to define the signaling hierarchy and integration. (iii) The function of identified very fast responding transcriptional regulators of the AP2/EREBP family and a NAC transcription factor will be studied in vitro and in vivo. (iv) Discrepancies between transcript accumulation and protein amounts indicate posttranscriptional regulation being most likely under control of retrograde signals that will be addressed using FLAG-epitope tagged ribosomal protein L18 Arabidopsis lines to compare total and ribosome-bound mRNA. This will complement our attempt to decipher the combinatorial effect of redox, abscisic acid and metabolite cues in retrograde signaling at the posttranscriptional level.

• DFG Programme: Research Units
• Subproject of: FOR 804: Retrograde Signalling in Plants