PARENT SESSION
Posters P6B Photosynthetic acclimation: Mechanisms and gene expression. Abstracts (531-578)

Retrograde plastid redox signals in the expression of nuclear genes for chloroplast proteins of Arabidopsis thaliana. Vidal Fey¹, Raik Wagner¹, Katharina Bräutigam¹, Thomas Pfannschmidt^*,1, ¹ Friedrich-Schiller-University Jena, Department for Plant Physiology, Dornburger Str. 159, Jena, Germany

ABSTRACT- Excitation imbalances between photosystem I and II generate redox signals in the thylakoid membrane of higher plants which induce acclimatory changes in the structure of the photosynthetic apparatus. They affect the accumulation of reaction centre and light harvesting proteins, chlorophylls a and b and transcripts for chloroplast reaction centre genes. Since chloroplast protein complexes are comprised of of plastid and nuclear encoded components we analysed the impact of these redox signals on nuclear gene expression. Studies of mutants with lesions in cytosolic photoreceptors or in chloroplast-to-nucleus communication indicate that the defective components are not essential for the perception or transduction of light-quality induced redox signals. Light quality shift experiments combined with application of the electron transport inhibitor DCMU have been performed to identify redox-regulated nuclear genes using DNA macroarrays. Our data point to a distinct role of photosynthetic redox signals in the regulation of plant gene expression which act independently and/or above of cytosolic photoreceptor or known chloroplast-to-nucleus communication avenues.

KEY WORDS: gene expression, photosynthesis, redox control, retrograde signalling